Abstracts from the 2014 Combined Scientific Meeting: Imaging and Radiation in Personalised Medicine. 4-7 September 2014, Melbourne Convention and Exhibition Centre, Melbourne, Australia. This supplement is a joint publication with the Journal of Medical Imaging & Radiation Oncology: Vol. 58, Suppl. 1, September 2014, Pages 1-352.

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Journal of Medical Imaging and Radiation Oncology (2014) 58, 184–343 Journal of Medical Radiation Sciences (2014) 61, 184–343

2014 Combined Scientific Meeting Imaging and Radiation in Personalised Medicine

Volumetric modulation arc therapy compared with intensity-modulated radiation therapy for malignant pleural mesothelioma C Albiez, D Papworth, A Kaminski and J Frantzis Genesis Cancer Care, Queensland, Australia

4–7 September 2014 Melbourne Convention and Exhibition Centre Scientific Exhibits Adjuvant external beam radiotherapy after therapeutic groin lymphadenectomy for patients at risk of nodal relapse: a dosimetric comparison of three-dimensional conformal and intensity modulated techniques G Adams,1 M Foote,2 S Brown,2 E Burmeister2 and B Burmeister2 1

Oceania Oncology Bundaberg, Queensland, Australia,

2

Princess Alexandra Hospital Brisbane, Queensland,

Australia Aim: To assess whether intensity modulated radiotherapy (IMRT) offers any advantages compared to three-dimensional conformal radiotherapy (3DCRT) when treating the ilio-inguinal lymph-node basin after therapeutic lymphadenectomy for melanoma. Method: 15 consecutive patients receiving adjuvant radiotherapy (48 Gy in 20 fractions) were selected for the study. Simulation, volume generation and goals for target volume coverage and organ at risk (OAR) avoidance followed departmental protocols. For each patient optimised 3DCRT and IMRT plans were generated with prescriptions in accordance with International Commission on Radiation Unit 50 and 62 (3DCRT) and 83 (IMRT) guidelines. Dose volume histograms were produced for each plan in order to allow direct comparisons of 3DCRT and IMRT plans for each patient. The Wilcoxon signed-rank test was used to compare dose received to both target and OARs from each plan for individual patients. Results: Conformality index was improved by the use of IMRT; median 0.649 (range 0.476–0.808) vs 0.442 (0.288–0.605); W = 2, p ≤ 0.05 for IMRT and 3DCRT respectively. No difference was seen in the homogeneity index; median 10.92 (7.65–28.67) vs 11.17 (8.96–26.69); W = 31, p > 0.05. Median dose to the bowel closest to the target volume was significantly less for IMRT. D1 cc, 10 cc and 40 cc were 48.5 Gy vs 49.7 Gy; 47.8 Gy vs 49.0 Gy and 45.8 Gy vs 48.2 Gy for IMRT and 3DCRT respectively. W values 14, 2 and 10; p ≤ 0.05 for all. Also reduced with IMRT was dose to the ipsilateral femoral neck; median V43.2 Gy, 3.9% (0.1–22.0%) vs 43.2% (12.4–68.5%), W = 0, p ≤ 0.05; and median V36 Gy, 29.5% (14.8–42.3%) vs 61.1% (40.4– 100%), W = 0, p ≤ 0.05 for IMRT and 3DCRT respectively. Conclusion: A homogenous coverage of the target volume can be achieved with both IMRT and 3DCRT (homogeneity index 1 cm. Conclusion: SpaceOAR Hydrogel was successfully injected in 29/30 patients with minimal side effects. Dosimetric benefits were greater at the higher rectal doses (V65 to V80), although lower range rectal doses (V30–V40) were also improved but to a lesser extent. MRI should be used for planning purposes as the gel is not well visualised on CT.

Aim: We aim to audit the findings of unenhanced multi-detector CT (CT KUB) for the assessment of acute presentations of renal colic for obstructive urinary calculi versus other findings or no findings in a regional Australian centre and compare this to published primary literature values. Methods: Data were collected retrospectively of 100 consecutive patients who underwent CT KUB for the investigation of obstructive urinary calculi and renal colic. The findings were audited and classified as (1) obstructive urinary calculus found, (2) alternative explanation of pain found in the absence of (1), (3) no cause found. Clinically significant and insignificant incidental findings were also noted separately. Patients with known urinary calculi including progression studies and stent follow-up or placement were excluded. Results: Of the CT KUB scans audited, 58% demonstrated obstructive urinary calculi (a positive scan). Gender analysis found an equal rate of positive scans; however, there were differences in the aetiologies of explained pain in negative scans that are gender specific such as ruptured penile implant in a male and uterine/ovarian pathology in a female. An alternative possible cause of the pain was found in 38% of negative scans. In positive scans, clinically significant incidental findings were discovered in 7% while clinically insignificant findings were discovered in 28% of cases. Negative scans meanwhile found only 1% of clinically significant, and 21% clinically insignificant findings. Conclusion: CT KUB is the mainstay technique in the assessment of obstructive urinary calculi as it is able to detect calculi not visible plain film x-ray1. X-ray has a high specificity but low sensitivity (45–58%) for detection of urinary calculi, while CT KUB also demonstrates a high specificity but with a high sensitivity of 96%2. The published literature values for positive scan rates are between 44% and 67%, and this audit is consistent with these findings3,4. References 1. Patatas K, Panditaratne N, Wah TM, Weston MJ, Irving HC. Emergency department imaging protocol for suspected acute renal colic: re-evaluating our service. The British Journal of Radiology 2012; 85: 1118–22. 2. Chen MY, Zagoria RJ, Saunders HS et al. Trends in the use of unenhanced helical CT for acute urinary colid. AJR Am. J. Roentgenol. 1999; 173: 1447–50. 3. Chowdhury FU, Kotwal S, Raghunathan G et al. Unenhanced multidetector CT (CT KUB) in the initial imaging of suspected acute renal colic: evaluating a new service. Clinical Radiology 2007; 62: 970–77. 4. Jo H and Buckley BT. Assessment of referral patterns for CT KUB in a tertiary setting. Journal of Medical Imaging and Radiation Oncology 2009; 53: 516–21.

Journal of Medical Imaging and Radiation Oncology and Journal of Medical Radiation Sciences © 2014 Combined Scientific Meeting

Scientific Exhibits Effect of abdominal CT in the assessment of non-traumatic acute abdominal pain in a regional emergency department A Al-Hindawi, M Seleem and J Van den Bogaerde

187 Bleaching of OSLDs in the ACDS level one audit A Alves, L Dunn, J Lye, A Cole, J Kenny, J Lehmann and I Williams ACDS/ARPANSA, Melbourne, Victoria, Australia

Nambour General Hospital, Queensland, Australia Aim: To evaluate the utility of abdominal CT scans requested from the Nambour General Hospital emergency department (Nambour ED) in the diagnosis of non-traumatic acute presentations of abdominal pain. Method: A retrospective analysis of 100 consecutive abdominal CT scans requested from the Nambour ED was conducted. Request forms were audited against the findings of the corresponding radiology reports. The findings of these were categorised as (1) possible cause confirmed, (2) alternative possible cause of symptoms identified in the absence of (1), and (3) no cause found. CT reports that noted poor quality of scans were excluded. Results: From 100 patients, 67 were found to have a possible cause of symptoms. 43 of these 67 positive findings (64%) were the queried cause found as per the request form. 24 of the 67 positive results (36%) found a cause other than that requested. Gender analysis found that females were more likely not only to have a cause found (46% vs. males 37%), but also more likely to have the queried cause found (25% vs. males 21%). The most common single pathological diagnosis was diverticulitis (18%). Further chart review demonstrated a close relationship between the diagnosis at discharge to the diagnosis from the CT scan. Conclusion: Abdominal CT is one of the most useful tools in the assessment of non-traumatic acute abdominal pain in emergency departments and is being utilised at increasing rates1,2. There is a strong correlation between the CT diagnosis and the final discharge diagnosis of a patient while a normal scan resulted in a low likelihood for ward admission3,4. Furthermore, a normal scan facilitated discharge from the emergency department. Whether a CT scan was required or whether the cause of abdominal pain could be assessed clinically without the need for CT scanning is difficult to ascertain retrospectively.

Aim: Until now optically stimulated luminescence dosimeters (OSLD) used in the Australian Clinical Dosimetry Service (ACDS) level one postal audit have been used once. Our aim is to find the conditions required to effectively bleach the OLDS to remove the dose recorded in past audits and to determine if the previously characterised element correction factor (ECF) needs to be re-measured for every audit batch. Method: A sub batch of 20 OSLDs was processed through three level one audit cycles, with reference dose exposure performed on the Australian Radiation Protection and Nuclear Safety Authority (ARPANSA) linac and with bleaching under 50 W white light for 24 hours between audit cycles. The element correction factor – found through a CO-60 exposure – was measured in the first two audit cycles but left out in the third audit cycle. Results: After bleaching the recorded dose on the OLSD has been reduced to 0.02% of the dose from 1 Gy of radiation from C0-60. The differences in audit dose measurements from one audit cycle to another were found to be within the measurement uncertainty; therefore the bleaching has not affected the audit outcome. However we have found that the average sensitivity of OSLDs can vary from batch to batch, therefore if a new batch of OSLDs is constructed from a random group of OSLDs, post bleaching, the ECF must be re-measured in the new batch. Conclusions: Bleaching has been employed as method to erase recorded dose on OSLDs in the ACDS level one audit. The procedure of performing an ECF measurement for each audit batch has been maintained.

References 1. Nagurney JT, Brown DFM, Chang Y et al. Use of diagnostic testing in the emergency department for patients presenting with nontraumatic abdominal pain. The Journal of Emergency Medicine 2003; 25: 363–71. 2. Larson DB, Johnson LW, Schnell BM et al. National trends in CT USE in the emergency department: 1995–2007. Radiology 2011; 258: 164–73. 3. Rosen MP, Sands DZ, Longmaid HE et al. Impact of Abdominal CT on the Management of Patients Presenting to the Emergency Department with Acute Abdominal Pain. American Journal of Roentgenology 2000; 174: 1391–6. 4. Esses D, Bimbaum A, Bijur P et al. Ability of CT to alter decision making in elderly patients with acute abdominal pain. American Journal of Emergency Medicine 2004; 22: 270–2.


188

Scientific Exhibits

Dynamic assessment of the accuracy of the ACDS level one audit A Alves, L Dunn, J Lye, J Lehmann, J Kenny, A Cole and

Evaluation of different Wintson-Lutz analyses S Alzaidi, J Morales and S Gill

I Williams

Australia

Chris O’Brien Lifehouse, Camperdown, New South Wales,

ACDS/ARPANSA, Melbourne, Victoria, Australia Aim: The Australian Clinical Dosimetry Service (ACDS) has been performing a level one optically stimulated luminescence dosimeter (OSLD) postal audit since December 2011. During a commissioning period the ACDS developed the uncertainty budget and found a relative standard uncertainty of 1.3%. Our aim is to analyse 3 years of audit data since commissioning to monitor shifts in the uncertainty of the audit. Method: ACDS level one audits are performed in quarterly batches. Three uncertainties have been monitored here: (1) Read out uncertainty – by measuring the standard deviation in multiple OSLD read outs. (2) Calibration uncertainty – by irradiating two subsets of OSLDs under reference conditions on the Australian Radiation protection and Nuclear Safety Authority (ARPANSA) linac and monitoring uncertainty in calibrating the OSLD reader. (3) Internal reader correction uncertainty – by monitoring the uncertainty in the measurement of the internal reader check. Results: In the level one audit we have observed minor shifts in the uncertainties which we have attributed to procedural development and equipment ware. The observed shifts have not thus far been significant enough to affect audit score thresholds. However, we have demonstrated that our characterisation of uncertainties is sensitive to process variations. A variation in process caused by faulty equipment can potentially increase audit uncertainties beyond acceptable limits. On the other hand procedural developments can potentially decrease audit uncertainties thus improving the audit’s effectiveness. Conclusions: Audit data processing must not only process audit results but also dynamically evaluate the uncertainty budget and flag any increase in the uncertainty which would affect the audit score thresholds. Further, this type of analysis applies downward pressure on uncertainties and new technology or processes designed to decrease uncertainty can be quickly evaluated and appointed.

Aim: The Winston-Lutz Test (WLT) [1] is a quality assurance technique used to evaluate the linear accelerator radiation isocentre for stereotactic radiosurgery treatments. The WLT is based on taking EPID (Electronic Portal Imaging Device) images of a pointer with a radioopaque ball aligned to the isocentre using small x-ray fields at various gantry, couch and/or collimator angles. The aim of this study is to evaluate the different algorithms used at various radiotherapy centres in calculating the radiation isocentre for a Novalis Tx linear accelerator. Method: The WLT analysis used at Chris O’Brien Lifehouse is based on the PipsPro V4.0 analysis software. This has been reviewed and compared to the analyses used by other radiotherapy centres that also provide SRS treatments. These other analyses are based on in-house generated algorithms using EPID images [2]. The different WLT analyses algorithm require different sets of gantry, couch and collimator combinations and also use different sized fields. In the comparison, the same set of WLT images were used to ensure true comparisons between the analyses. The RIT analysis software is also included in the evaluation. Results: The results show that the analyses are very similar in essence; however, different combinations of gantry, couch and collimator sets can shed light into issues that can go undetected if no additional cone mount concentricity QA tests are being carried out on the linear accelerator. Conclusion: Results from different WLT analyses have assisted in understanding and confirmed the consistency of the radiation isocentre of the linear accelerator. References 1. Winston KR, Lutz W. Linear accelerator as a neurosurgical tool for stereotactic radiosurgery. Neurosurgery 1988 April; 22 (No 3): 454–64. 2. Chojnowski J, Gajewski R. An automatic method of the isocentre position verification for micromultileaf collimator based radiosurgery system. APESM 2010 December 24; 34 (No 1): 15–21.


Scientific Exhibits

189

Implementing a left-sided breast deep inspiration breath hold technique using ABC by Elekta. The POW experience J Ambat, D Au, M Gurram, S Corde and R Martin Prince of Wales Hospital, New South Wales, Australia

Oral cavity dose drives dysphagia in definitive (Chemo) IMRT for head and neck cancer N Anderson,1 J Jackson,1 V Khoo,1,2 M Schneider,3 M Fahandej,1 M Rolfo,1 H Gan,4 K Kaegi,1 F Sneyd,1 D Lim Joon1 and M Wada1 1

Aim: To implement a Deep Inspiration Breath-Hold (DIBH) technique at the Prince of Wales Hospital, Randwick, using the Active Breathing Coordinator (ABC) device by Elekta, for the treatment of left-sided Breast cancers, in order to reduce dose to the heart in patients treated on a Siemens Linear Accelerator. Method: In December 2013, we implemented a DIBH technique for patients with left-sided breast cancer who are under the age of 55 years old, and have a volume of irradiated heart of greater than or equal to 28 cm3, if treated using a conventional tangent technique. The 53-year-old female patient presenting with a left sided T1bN0M0, hormone receptor positive HER-2 negative breast cancer. We compared three plans – conventional free-breathing (FB) plan, breast-cup free-breathing plan, and a breast-cup breath-hold plan to evaluate the benefit of receiving treatment using a breath-hold technique. The patient was planned in Xio using a 6 MV EBRT tangent technique, prescribed a hypo-fractionated regime (42.4 Gy/16 fractions). This was followed by a hypo-fractionated boost (10 Gy in 4 fractions), using a direct electron beam. The radiation oncologist and radiotherapists selected the breast-cupDIBH plan and the patient completed RT using the DIBH technique. Results: The mean DVH doses for the organs at risk (OAR):

OAR

Left lung Heart

Standard setup (FB)

Breast cup (FB)

Breast cup (DIBH)

798 cGy 726 cGy

644 cGy 514 cGy

580 cGy 251 cGy

Conclusion: The DIBH technique was implemented successfully. This technique may be further improved with gating technique to be used, particularly for 3/4-field breast treatments using IMRT. With the increase in women under the age of 50 being treated for breast cancers due to earlier detection and increased awareness, heart dose is a factor that needs to be considered for these patients as they have a greater life expectancy1. DIBH is a technique that will reduce the risk in late heart toxicity (i.e. pericarditis, pancarditis). Reference 1. Zurl B, Stranzl H, Winkler P, Kapp KS. Quantification of contralateral breast dose and risk estimate of radiation-induced contralateral breast cancer among young women using tangential fields and different modes of breathing. Int J Radiat Oncol Biol Phys 2013 Feb 1; 85(2): 500–5. doi: 10.1016/j.ijrobp.2012.04.016. Epub 2012 May 26.

Olivia Newton John Cancer and Wellness Centre, Austin

Health, Victoria, Australia, 2Department of Clinical Oncology, Royal Marsden NHS, Chelsea, United Kingdom, 3

Department of Medical Imaging and Medical Radiations

Sciences, Monash University, Melbourne, Australia, 4Ludwig Institute for Cancer Research, Austin Health, Melbourne, Australia Purpose/Objectives: Patients with cancers of the head and neck undergoing definitive intensity modulated radiotherapy (IMRT) invariably experience some degree of dysphagia. Enteral feeding tubes (FTs) are often employed in the setting of severe dysphagia, to maintain patient nutritional requirements. Persistent use of FT is a surrogate for severe dysphagia. This study examined the association between swallowing organs at risk (SWOAR) dosimetry and the duration of heavy FT (see below) use. The aim of this study was to identify dosimetric factors prognostic for dysphagia to assist in the streamlining or omission of FT insertion. Methods/Materials: This study identified 106 patients treated with definitive IMRT between 2007 and 2012. Gross disease was treated to 70 Gy in 35 fractions (7 weeks) with bilateral neck irradiation to 56 Gy. FT duration and intensity was gleaned from a prospective nutritional database to identify heavy feeding patients – defined by FT use for ≥75% of nutritional requirements for >6 weeks. SWOAR were delineated retrospectively, and included superior, middle and inferior pharyngeal constrictors (PCM), base of tongue (BOT), oesophageal inlet muscle (EIM), cervical esophagus (CE), glottis (GL), supraglottis (SGL) and cricopharyngeus muscle (CPM) – based on UMCG delineation guidelines. Oral cavity (OC) was also defined. Differences in frequency distributions of dose mean (Dmean) above and below 50 Gy were analysed for all SWOAR and OC. Results: OC Dmean 95%) in 8 out of 10 cases; the prostate-PTV margin served its intended purpose. In 3 cases a shift of only 2 mm pushed the urethral dose outside the clinical constraint (D10% < 17.5 Gy). In no cases was the rectal constraint D2 cc < 11.8 Gy exceeded, although a simulated needle shift inferiorly increased the rectal dose due to the inferior aspect of the rectum extending anteriorly. Conclusion: Small systematic shifts in needle position can lead to loss in target coverage and urethral doses exceeding clinical tolerance levels. Care should be taken when reporting free needle lengths.

Aim: To present the radiologic findings of an unusual presentation of pericardial cyst with pathologic correlation. Case Study: A 33-year-old female presented with a 3 day history of pleuritic central and right sided chest pain. There was no history of preceding trauma. Chest X-ray on admission demonstrated a very subtle density at the right cardiophrenic angle. CT pulmonary angiogram (CTPA) was performed and showed no evidence of pulmonary embolism. A thickwalled low density, peripherally enhancing lesion was detected at the right cardiophrenic recess. An MRI scan was then performed and the patient underwent surgical resection of the lesion with pathological confirmation of a benign pericardial cyst complicated by haemorrhage and traumatic fat necrosis. Discussion: Pericardial cysts are usually benign, asymptomatic, mediastinal lesions. Symptomatic presentation of pericardial cysts is uncommon. Chest pain has been reported with torsion of the cyst or inflammation. Haemorrhage into pericardial cysts is unusual and can occur spontaneously, but has also been reported after blunt chest trauma. Our case illustrates an uncommon presentation of pericardial cyst with spontaneous haemorrhage. No evidence of infective cause was identified on pathology or microbiology examinations.


192 A rapid learning infrastructure for implementing a laryngeal carcinoma survival prediction model T Lustberg,1,3,4, M Bailey,1,5,8 M Carolan,1,5,8 A Miller,1,5,9 L Holloway,2,3,5,6,7 G Delaney,2,6,7 D Thwaites3 and A Dekker1,2,3,4 1

Illawarra and Shoalhaven Cancer Care Centres, New South

Wales, Australia, 2Liverpool and Macarthur Cancer Therapy Centres, New South Wales, Australia, 3Institute of Medical Physics, School of Physics, University of Sydney, New South Wales, Australia, 4Maastricht Radiation Oncology (MAASTRO), Maastricht, The Netherlands, 5Centre for Medical Radiation Physics, University of Wollongong, New

Scientific Exhibits

can be used in future to personalise treatment, improve treatment quality and evaluate these practice changes. The model does not work well for the biased patient population in the RTOG dataset. References 1. Egelmeer AGTM, Velazquez ER, de Jong JMA et al. Development and validation of a nomogram for prediction of survival and local control in laryngeal carcinoma patients treated with radiotherapy alone: a cohort study based on 994 patients. Radiother Oncol 2011 Jul; 100(1): 108–15. 2. Weber RS, Berkey BA, Forastiere A et al. Outcome of salvage total laryngectomy following organ preservation therapy: the radiation therapy oncology group trial 91-11. Arch Otolaryngol Neck Surg 2003 Jan 1; 129(1): 44–9.

South Wales, Australia, 6South Western Clinical School, University of New South Wales, New South Wales, Australia, 7Ingham Health Research Institute, New South Wales, Australia, 8Illawarra Health and Medical Research Institute, New South Wales, Australia, 9Center of Oncology Informatics, University of Wollongong, New South Wales, Australia Aim: Data quality of routine patients is of vital importance when creating an infrastructure for rapid learning. The aim of this work is to provide a platform that enables rapid learning for laryngeal carcinoma patients and prove the clinical relevance of the survival prediction model (1) as a first step to multi institutional rapid learning. Method: Data extraction and mining tools were used to collect the input parameters from Illawarra Cancer Care Center’s (ICCC) OIS system (MosaiQ). The MAASTRO dataset (1) was used to determine the prognosis range for good, medium and poor prognosis patients so it could be applied to the ICCC dataset and to validate the new implementation of the model. To evaluate the model performance the Area Under the Curve (AUC) spread for each dataset was calculated using bootstrapping. A similar approach was applied to the radiotherapy only arm of the RTOG-91-11 trial dataset (2). Results: Data mining identified 125 laryngeal carcinoma patients, resulting in 109 that were eligible to be evaluated by the model to predict 2 year survival. Bootstrapping resulted in a normally distributed AUC reliability interval (+/–2SD) of 0.61 to 0.84, 0.47 to 0.67 and 0.74 to 0.82 for the ICCC, RTOG-9111 and MAASTRO datasets respectively. The model classified poor and medium prognosis patients in the ICCC set but the good prognosis patient group was very small, as the ICCC patient population was older, had more advanced cancers, more nodal spread and more non-glottic cancers which are unfavourable for the survival prognosis.

Fig. 1. Kaplan–Meier survival curves for MAASTRO (A), ICCC (B) and RTOG-9111 (C). Conclusion: The technical infrastructure and model is able to support the prognosis prediction of laryngeal carcinoma patients in ICCC which


Scientific Exhibits

193

A comparison of Intensity Modulated Radiation Therapy (IMRT) and HybridArc (TM) treatment plans for spinal tumours N Bailey

A comparative study of Monte Carlo and Pinnacle3 dose distributions for stereotactic treatment fields in lung and lung-based lesions J Baines, S Zawlodzka, M Chan and T Markwell

Epworth Radiation Oncology, Richmond, Victoria, Australia

Radiation Oncology Mater Centre, South Brisbane, Queensland, Australia

Aim: HybridArc™ (Brainlab, AG) is a treatment technique blending aperture-enhanced dynamic conformal arc therapy with discrete IMRT beams. This study dosimetrically compares HybridArc with IMRT in Stereotactic Body Radiotherapy (SBRT) for spinal tumours. Method: In a retrospective study of 10 patients with metastatic thoracic or lumbar spinal disease, the dosimetric results of a 7 field IMRT distribution were compared against a single 320–340 degree HybridArc™ distribution containing three to four fixed-port IMRT fields. Planning was performed using the Brainlab iPlan RT Dose 4.5.3 platform. Treatment plans were designed to deliver a homogeneous dose of 40 Gy to Planning Target Volume (PTV) Spine with a simultaneousintegrated-boost to the tumour to a total dose of 50 Gy. Planning objectives were 90% of prescribed dose to cover 100% of PTVs, while minimising the maximum spinal cord point dose to 34 Gy. A comparison of target and Organ At Risk dose volume histograms, maximum and minimum target dose, and conformity index was used to evaluate each planning technique. Planning time, mean beam-on time and Monitor Units were also analysed. Results: Both IMRT and HybridArc™ produced clinically acceptable treatment plans; HybridArc™ incorporating 4 IMRT beams generally produced superior results when compared to HybridArc™ incorporating 3 IMRT beams. Superior PTV coverage and lower maximum dose was achieved more often with IMRT plans compared with HybridArc™. The conformity index for the IMRT distributions was generally lower, correlating to improve sparing of normal tissues. Planning times were less for IMRT plans due to the time taken to optimise both aperture and IMRT beams for HybridArc™. Conclusion: Epworth Radiation Oncology will continue to use IMRT as its modality of choice for SBRT of spinal tumours as the dosimetric qualities are generally superior to HybridArc™, and efficiencies are achieved in the planning process.

Aim: The goal of this study is to assess the accuracy of Pinnacle3 treatment planning system in calculating the dose to the lung-based lesions in a presence of stereotactic treatment beams. Method: Monte Carlo (MC) codes BEAMnrc and DOSXYZnrc (National Research Council of Canada, Ottawa, ON) were used to calculate dose profiles for a 6 MV Varian Clinac 21iX beam normally incident on a surface of a phantom consisting of a 20 × 20 × 10 cm3 lung layer (density 0.1–0.35 g/cm3) positioned between two 20 × 20 × 5 cm3 layers of water. Lung lesions of sizes ranging from 1 cm3 to 3 cm3 and density of 1 g/cm3 were located on the beam axis at distances 2 cm, 5 cm and 7 cm from the upstream water–lung interface. Simulated MLC defined radiation fields, sizes 2 × 2 cm2 to 8 × 8 cm2, were used with 10 × 10 cm2 jaw setting. Using an equivalent beam arrangement and phantom model the Pinnacle3 Collapsed Cone Convolution (CCC) algorithm was used to calculate dose distributions for comparison with corresponding MC simulations. Results: As the lung density is decreased from 0.35 to 0.1 g/cm3 significant differences between Pinnacle3 TPS and MC were apparent for small fields both upstream and downstream from the lesion location and generally the TPS underestimates the lung dose (absolute difference up to ∼7%). However, immediately distal to a water–lung interface the TPS overestimates dose. Furthermore at lung–lesion and lesion– lung interfaces MC predicts larger and smaller doses, respectively, relative to the TPS. There is also evidence to suggest that the TPS underestimates the dose coverage across the lesion region. Conclusion: In Stereotactic Body Radiation Therapy (SBRT) dose protocols prescribe to an isodose line typically 70–80% covering the PTV surface. For a lung density approaching 0.1 g/cm3 the findings of this study suggests that the dose prescription based on the isodose at the upstream lung–lesion interface is likely to underestimate the maximum dose within the ITV.


194

Scientific Exhibits

Abdominal endovascular aortic repair (EVAR): comparison of image fusion (IF3D) angiography versus conventional (2D) angiography with respect to intravenous contrast dose, radiation dose and total fluoroscopy time N Bajic,1 T Kurmis,2, K Doan,1 R Sebben,3 R Fitridge,1

Computed tomography (CT) imaging following Whipple procedure: a pictorial essay of normal postoperative findings and complications A Bangaragiri, N Venkatanarasimha and H Salahudeen

and J Dawson2

Aim: CT plays a pivotal role in detecting post surgical complications following pancreaticoduodenectomy, also referred to as Whipple procedure. The purpose of this pictorial review is to present the normal post operative findings and complications seen on CT. Methods: CT images of patients who underwent Whipple procedure in our institution, in the immediate post operative period and on follow up, demonstrating normal features and complications were included in this pictorial essay. Results: The two common indications for pancreaticodudenectomy are periampullary tumours and chronic pancreatitis. The surgical procedure is complex comprising of resection of the pancreatic head, the duodenum, a short segment of the jejunum, and the gastric antrum. This is followed by pancreaticojejunostomy, hepaticojejunostomy, and gastrojejunostomy or duodenojejunostomy anastomoses. CT is vital in detecting complications following surgery; these are broadly divided in to 1) those that are related to the procedure such as delayed gastric emptying, anastomotic leak, infections and vascular complications, and 2) those that are related to the disease such as local recurrence and metastasis. Conclusion: Complications following Whipple procedure are not uncommon. Radiologists should be familiar with the normal appearances to avoid misinterpretation, and be able to recognise the complications, which are crucial for further appropriate management.

1

Queen Elizabeth Hospital, South Australia, Australia, 2Royal

Adelaide Hospital, South Australia, Australia, 3SA Health, South Australia, Australia Aim: Evaluate the introduction of image fusion (IF) of preprocedural computed tomography arterial phase images with real-time procedural fluoroscopy (3D angiography) as a roadmap in abdominal endovascular repairs (EVARS) compared with conventional DSA intraprocedural roadmaps (2D angiography). This study aimed to compare parameters between 2D and IF3D groups including intravenous contrast dose (mL); total radiation dose (dose area product [DAP])(Gy/cm2); total skin dose (mGy) and total fluoroscopy time during examination (minutes). Method: 46 consecutive patients with abdominal aortic aneurysms (AAA) treated with conventional fluoroscopy (2D) techniques in an angiography suite without IF capabilities (2D) was compared with 50 consecutive patients with AAAs treated after the introduction of an IF capable angiography suite (IF3D) were retrospectively reviewed. All procedures performed at the same institution with the same operators, either with the non-IF or IF capable angiography suites. Parameters compared between the 2D and IF3D groups include intravenous contrast dose (mL); total radiation dose (dose area product [DAP])(Gy/ cm2); total skin dose (mGy) and total fluoroscopy time during examination (minutes). Data distribution was non-parametric according to visual analysis and formal normality testing (D’Agostino & Pearson, Shapiro–Wilk and Kolmogorov–Smirnov test) and therefore a Mann– Whitney test was utilised for all continuous data. Results: No significant difference in procedure success rates between the two groups. IF3D group displayed a significant reduction in IV contrast volume administered (IF3D 115 mL (95–140) vs 163 mL (110– 225), p = 0.0002). IF3D group tended towards lower radiation dose (mGy); however, this was not statistically significant. IF3D was associated with significant reduction in overall fluoroscopy time per procedure (20.4 minutes (18.0–28.2) vs 31.6 minutes (25.8–44.1), p < 0.0001). Conclusion: Image fusion roadmaps have shown to successfully reduce IV contrast volume and decrease total fluoroscopy time for abdominal EVAR procedures. In addition, there tends to be a (nonsignificant) decrease in the total radiation exposure with IF angiography.

Singapore General Hospital, Singapore


Scientific Exhibits

195

Comparing four-dimensional cone beam CT ventilation imaging with Technegas SPECT in lung SBRT: first results from a new imaging study J Kipritidis,1 F Hegi-Johnson,1,2,3 J Barber,3 K West,3

The current status of lung and spine Stereotactic Ablative Body Radiotherapy techniques in Australasia: a report from a 2014 SABR workshop J Sykes,1,2,3 S Yau,1,2 K Van Tilburg,1 S White,1 J Barber1 and

K Unicomb,3 C Bui,4 R Yeghiaian-Alvandi3 and P Keall1

D Thwaites3

1

1

Radiation Physics Laboratory, University of Sydney,

Nepean Cancer Care Centre, Kingswood, New South

Camperdown, New South Wales, Australia, 2Central Coast

Wales, Australia, 2Princess Mary Cancer Care Westmead,

Cancer Care Centre, Gosford Hospital, Gosford, New South

Australia, 3Institute of Medical Physics, School of Physics,

3

Wales, Australia, Nepean Cancer Care Centre, Radiation

Sydney University, Australia

Oncology Network, Penrith, New South Wales, Australia, 4

Department of Nuclear Medicine, Nepean Hospital, Penrith,

New South Wales, Australia Aim: Four-dimensional cone beam CT ventilation imaging (4D-CBCT VI) could enable functional lung imaging in the radiotherapy treatment room for the first time, but requires validation. We are performing the first quantitative correlation study between 4D-CBCT VI and Technegas ventilation SPECT (V-SPECT). We hypothesise that 4D-CBCT VI can act as a surrogate for V-SPECT. Method: Three early stage lung cancer patients received 3–6 prefraction 4D-CBCT scans for lung SBRT. Patients also received a pretreatment V-SPECT scan in the treatment planning position. 4D-CBCT VIs were generated by applying B-spline deformable image registration to obtain the Jacobian determinant of deformation between the end-exhale and end-inhale phases. All 4D-CBCT VIs were manually aligned to the corresponding V-SPECT image and cropped to the side of the lung ipsilateral to the primary tumour (Figure 1). We assessed the agreement of 4D-CBCT VI and V-SPECT by computing the Spearman correlation r across all ventilation voxel pairs, and the Dice similarity d_high and d_low for high and low functioning lung respectively. The cutoff was set at the 20th percentile value in each 4D-CBCT or SPECT ventilation image.

Aim: In January 2014, Nepean Cancer Care Centre hosted a workshop for SABR lung and spine techniques. The workshop brought together delegates from across Australia and New Zealand, from the three main radiation therapy professions. Method: All Radiation Oncology centres with delegates attending the workshop were asked to complete a pre-workshop questionnaire covering technical and process aspects of SABR treatments. They were also invited to complete lung and spine SABR contouring exercises. Discussion during the workshop was encouraged and extended with an online discussion forum. Results: 151 delegates attended the workshop, representing 35 RO centres. Of the 25 responding centres to the pre-workshop questionnaire, lung/spine SABR was treated routinely in 8/2 centres, 8/7 had just started and 3/2 were commissioning and 5/14 had not started. The majority of centres have treated less than 5/5 to date although 6/0 centres have treated in excess of 20. Patient numbers were projected to increase rapidly. The lung/spine SABR contouring exercises were completed by 5/3 centres. Apart from one result, the lung ITV volumes were consistent (Mean ± Standard deviation = 35.7 ± 3.7 cm3; Outlier = 86.7). The agreement measured using the Dice Similarity Coefficient was 0.90 ± 0.02. Greater variance was seen in spine; CTV volumes (30.7 ± 5.7 cm3 with Dice 0.81 ± 0.12). The two most discussed points were a) should all centres be treating with SABR techniques and b) who should be present at delivery to ensure the patient is correctly positioned. Conclusion: While SABR is a relatively new technique across Australasia, experience is growing rapidly with the number of centres treating SABR lung and spine increasing. The workshop was successful in providing education and a forum for discussion amongst the SABR community. There is a need for further similar workshops to meet the growing demand.

Fig. 1. Comparing coronal views of 4D-CBCT VI (left) and V-SPECT (right).

Results: Averaged across all 3 patients, correlations were poor-tomoderate, with r = (0.16 ± 0.30), d_high = (0.77 ± 0.30) and d_low = (0.25 ± 0.10). However, one patient exhibited significantly better correlations with less variation; with r in the range (0.35–0.47), d_high in the range (0.75–0.78) and d_low in the range (0.27–0.40) across four 4D-CBCT VIs. Conclusion: These are the first results in an ongoing correlation study between 4D-CBCT VI and Technegas V-SPECT. We have shown that moderate correlation is possible; our full study will expand this analysis to 30 patients and consider possible clinical applications for 4D-CBCT VI.


196

Scientific Exhibits

What are the real benefits of electronic magnification for soft copy mammography? J Barclay

Quantifying volume of intracerebral, subdural and extradural haemorrhage: as easy as ABC/2 CDJ Barras, BM Tress and PM Desmond

Wesley Breast Clinic, Hendra, Queensland, Australia

Department of Radiology, Royal Melbourne Hospital, The University of Melbourne, Victoria, Australia

A review of using current electronic magnification techniques in softcopy mammography. Australia has been one of the last of the developed world to move to soft copy reporting of digital mammography. With the transition to soft copy reporting, a number of questions have surfaced surrounding best practice regarding digital viewing techniques, with recent incidents in the South Australian Breast Screening Program also bringing this to attention(1). Digital magnification of images is one of the leading features soft copy mammography reading (2), however with only recent use in Australia there has been little clarity on the benefits of its use. There is currently limited research available in this new field, however international investigations have pointed toward no significant trend for a specific “magnification” factor performing better than others. Furthermore, there is some evidence that digital zoom may be as useful as a magnification mammography view in some cases, with benefits including reduction in radiation dose to the patient.

Aim: Intracerebral haemorrhage (ICH) is the most fatal form of stroke. ICH volume is a powerful predictor of morbidity and mortality and also correlates with outcome in subdural and extradural haemorrhage. Radiology reporting of these forms of intracranial haemorrhage has usually been limited to axial imaging size assessment. A simple method for rapid calculation of intracranial haemorrhage volume from multiplanar imaging in the emergency radiology setting is required, with direct prognostic significance for patients. Method: A simplified ellipsoid formula ABC/2 has been used for ICH volume calculation since the 1980s. In this technical presentation, a methodology for application of the formula using multiplanar reformats is presented, adapted for the different morphologies of intracerebral, subdural and extradural haemorrhage. Results: Mathematical derivation of the ellipsoid formula is described. The technique of ICH volume calculation from multiplanar reformats is described for ICH, subdural and extradural haemorrhage. Limitations, clinical and research implications are described. Conclusion: Rapid calculation of ICH, subdural and extradural haemorrhage volume is possible using the simplified ellipsoid formula ABC/2. The reporting of these intracranial haemorrhage volumes has direct implications for patient prognosis in the emergency radiology setting.


Scientific Exhibits An audit of provisional versus final reports of on-call CT imaging L Barrett, R Barrett and C Hacking The Royal Brisbane and Women’s Hospital, Queensland, Australia

197 External beam radiotherapy with high dose rate brachytherapy boost with two fractions and two implants: early results using our contemporary technique A Bece,1,2 N Patanjali1 and G Hruby1 1

Chris O’Brien Lifehouse, Camperdown, New South Wales,

Australia, 2Royal Prince Alfred Hospital, New South Wales, Aim: The goal is to improve reporting accuracy of registrar on-call CT reporting, to help target supervision and training. There is no defined standard of discrepancy rates for CT or for other imaging modalities. The literature from other centres report discrepancy rates of between 2.6% and 5.4%. Method: Excel programs were written to analyse and graphically display the proprietary data available for each CT examination. In this way the study investigated correlations between the discrepancy rate and specific factors which were: time of shift (e.g. evening or night shift), workload of shift and type of scan (e.g. body region scanned, trauma vs non-trauma). Results: Evening shift (1700–2200) invariably had the most examinations, with highest discrepancy rates at 2100–2200, coinciding with registrar handover. A second peak was identified at 0200–0400. “Non-contrast CT head” was the most frequent on-call examination type, but with the lowest discrepancy rate. Yet, the infrequently performed “CT Head Perfusion”, had a high discrepancy rate. “Abdomen”, “Head and C-Spine” and “CTPA” were the next most common examinations. Of these only “abdomen” had a relatively high discrepancy rate. Other examinations with relatively high error rates were “Trauma”, “Head and Neck (angiogram)” and “Neck (angiogram)”. Conclusion: Our findings suggest that registrar fatigue and unfamiliarity with the examination are associated with higher discrepancy rates of on-call CT reporting. Interestingly, of the more common examinations, the abdominal and trauma scans still incur relatively high discrepancy rates. We postulate this is due to increased complexity of the scans. The audit also highlighted technical problems in implementing research tools with the proprietary database. Reports are stored as unstructured data, and as such not designed for statistical analysis, as automated query cannot be performed. Further work, to classify the discrepancy types (e.g. missed findings vs interpretative, major vs minor), may require a prospective type study.

Australia Aim: Dose escalation with high dose rate (HDR) brachytherapy boost has demonstrated excellent long term disease control in men with localised prostate cancer. There exists a strong radiobiological rationale for large fraction sizes for prostate cancer (low α/β) and our own patient-reported outcomes studies suggest a preference for outpatient treatment. Consequently we have adopted a two fraction, two implant outpatient regimen. We present our early results with this technique and report on disease outcomes and toxicity. Method: Between May 2006 and July 2010, 80 patients received two fraction HDR brachytherapy boost followed by external beam radiation (46 Gy in 23 fractions). Brachytherapy was delivered with two separate implants over two weeks. During the study period, the dose was progressively increased from 8.5 Gy x 2 (40 patients) to 9.0 Gy x 2 (37 patients) and more recently 9.5 Gy x 2 (3 patients). There were 55 intermediate risk and 25 high risk patients in our cohort. 72 patients (90%) received androgen deprivation for 6 months or more. Results: At a median follow up of 4.2 years, 6 patients (7.5%) developed patients developed biochemical (3 patients) or clinical (3 patients) disease recurrence. 4-year actuarial disease free survival was 98.0% (intermediate risk) and 83.3% (high risk). No patients failed locally. 10 (12.5%) patients had grade 2 urinary toxicity requiring endoscopic intervention and 1 patient had a grade 3 urethral stricture. Median time to development of significant urinary toxicity was 2.2 years (0.8–3.4 years). The cumulative rate of grade ≥2 urinary toxicity rate at 4 years was XX. There were 2 (2.5%) patients with grade 2 and none with grade 3 rectal toxicity. Conclusion: The two fractions, two implant HDR boost technique is well-tolerated and offers encouraging disease control. Toxicities are comparable to our previous three fraction protocol and other published series.

References 1. The Royal College of Radiologists. Standards for Radiology Discrepancy Meetings. London: The Royal College of Radiologists; [updated August 2007, cited August 2013]. Available from URL: http://www.rcr.ac.uk/publications.aspx?pageid=310&publicationid =258 2. Ruchman RB, Jaegerz J, Wiggins EF et al. Preliminary radiology resident interpretations versus attending radiologist interpretations and the impact on patient care in a community hospital. AJR 2007; 189: 523–6. 3. Terreblanche OD, Andronikou S, Hlabangana LT, Brown T, Boshoff PE. Should registrars be reporting after hours CT scans? A calculation of error rate and the influencing factors in South Africa. Acta Radiol 2012; 53(1): 61–8.

Fig. 1. Kaplan–Meier disease free survival for intermediate and high risk patients.


198

Scientific Exhibits Open biomedical image analysis toolbox in the clouds T Bednarz and Y Arzhaeva CSIRO, Victoria, Australia

Fig. 2. Cumulative incidence of late urinary toxicity (grade ≥2).

This work demonstrates a novel way of carrying out image analysis, reconstruction and image processing tasks using cloud based service provided on the Australian National eResearch Collaboration Tools and Resources (NeCTAR, http://www.nectar.org.au) infrastructure. The toolbox allows free users access to a wide range of useful biomedical imaging functions that can be connected together in workflows allowing creation of even more complex algorithms that can be re-run on different data sets, shared with others or additionally adjusted. The functions given are in the area of cellular imaging, advanced X-ray image analysis, computed tomography and 3D medical imaging and visualisation. The service is currently available on the website http:// www.cloudimaging.net.au. Aim: The primary goal of this work was to provide improved access to biomedical image processing and analysis software packages developed by CSIRO to nationwide research communities via remotely accessible user-interfaces. Method: The toolbox provides many biomedical image analysis functions, that can be executed through web interfaces and combined together build up complex imaging workflows. Results: At the conference live demos will be presented, showcasing the toolbox’ capabilities. The project is free for research community and free accounts will be offered also to those who have no Australia Access Federation compatible accounts. Reference http://www.cloudimaging.net.au


Scientific Exhibits

199

Quantitative assessment of an interobserver delineation margin for breast radiotherapy treatment planning L Bell,1,2 E Pogson,1,2 P Metcalfe1,2 and L Holloway1,2,3,4 1

Centre for Medical Radiation Physics, University of

Wollongong, Wollongong, New South Wales, Australia, 2

Liverpool and Macarthur Cancer Therapy Centres and the

Ingham Institute, Liverpool, New South Wales, Australia, 3

SWSCS, University of New South Wales, Sydney, Australia,

4

Institute of Medical Physics, University of Sydney, Sydney,

Australia Aim: Interobserver delineation uncertainty has been shown to have a large impact on dose distribution and as such, should be accounted for in treatment planning.1,2 This study investigated the application of an anisotropic whole breast delineation margin to quantify the encompassment of the CTVs it was derived from. Method: 10 CT datasets were used in which the clinical target volumes (CTVs) were delineated by 8 observers. The standard deviation (SD) of the contours from the mean was determined at angular increments, on all slices. The margin was defined as 3.92 times the average SD of all patients, such that a 95% confidence interval of encompassing the contours would be achieved. For each patient, the margin was applied to each CTV and the volume overlap with each of the remaining CTVs was determined, with 100% representing complete overlap. The margin was applied to all contours in turn and the process was repeated. Results: An overlap of 90% or greater was arbitrarily considered successful accounting for some inaccuracy in the contour interpolation process when the origin of the coordinate system lay outside the contour. The range of percentage overlap values when the margin is applied to the smallest and largest contour for a selection of patients is presented in the table. The margin was ineffective when applied to the smallest CTV in all patients, as only 6 patients had all CTVs successfully overlapped. The effectiveness of the margin increased with CTV volume. When applied to the largest contour, 100% of patients CTVs were successfully encompassed.

Patient Smallest CTV (%range) Largest CTV (%range)

1 (Smallest)

5 (Median)

9 (Largest)

85.2–92.4 97.5–99.2

94.0–97.4 98.9–99.8

90.3–93.1 97.7–97.9

Fig. 1. Margin (pink) with respect to observer CTVs (green) for patient 1.

Conclusion: This whole breast anisotropic delineation margin is effective in accounting for interobserver uncertainty when applied to median and large volume CTVs. It is less effective when applied to small volumes. An investigation into delineation margins dependent on CTV volume would be appropriate. References 1. Stroom JC, Heijmen BJM. Geometrical uncertainties, radiotherapy planning margins, and the ICRU-62 report. Radiotherapy and Oncology 2002; 64: 75–83. 2. van Herk M, Remeijer P, Rasch C, Lebesque JV. The probability of correct target dosage: dose-population histograms for deriving treatment margins in radiotherapy. International Journal of Radiation Oncology*Biology*Physics 2000; 47: 1121–35.


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Scientific Exhibits

Commissioning of Elekta 6MV FFF Versa HD and Pinnacle L Bendall,1 I Patel,2 N McGrath2 and C Rowbottom2 1

Institute of Medical Physics, School of Physics, University

Patient QA for SABR using VMAT assessed in the transverse plane with radiochromic film N Bennie1,2 1

of Sydney and The Christie NHS Foundation Trust,

North Coast Cancer Institute, Lismore, New South Wales,

Manchester, United Kingdom, The Christie NHS Foundation

Australia, 2Centre for Medical Radiation Physics, University

Trust, Manchester, United Kingdom

of Wollongong, New South Wales, Australia

Aim: To commission the first 6 MV FFF beam within Pinnacle version 9.6 at the centre. Method: The linac was matched to Elekta “golden” data set and commissioning data collected, including open field profiles, PDDs, output factors, tissue standard ratios (TSRs) and cGy-MU factors. The data collected were reasonably similar to other Agility machines in the department, so a previous model was used as a starting point and tweaked to improve agreement between model and measurements. Changes required included the spectrum of the beam, the arbitrary profile, the off-axis softening factor and the electron contamination parameters. Model validation included: • MLC test fields delivered to Kodak EDR2 film and point doses measured in the water phantom • TSR calculation vs. measured • Clinical plan verification ∘ 4 field brick dose measurements (off-axis, various depths etc) ∘ IMRT plans – fluences and point dose comparisons ∘ VMAT plans – fluences and point dose comparisons. Results: The results of the model validation measurements showed a good agreement between the model and delivery (see Figure 1). Profiles were acquired at 6 MV_FFF with 90 cm FSD, at a depth of 10 cm. These profiles show that the magnitude and shape of the peaks and troughs in the bar test are a close match between Pinnacle and measured values. This confirms that the tongue & groove parameter (although the Agility leaves do not have an actual T&G), the MLC transmission (trough) and the additional interleaf leakage transmission (trough) are set appropriately to provide an accurate model of the machine.

Introduction: This paper presents a method for pre treatment Patient QA using radiochromic film in the transverse plane. The treatments being assessed are Stereotactic Ablative Radiotherapy (SABR) by Volumetric modulated arc radiotherapy (VMAT) delivery. This procedure forms part of a comprehensive QA assessment including both Patient and Beam QA. The other QA methods that are included in the assessment are point dose measurement (PDM) (ion chambers, diode), and dosimeter arrays including the SNC MapCheckTM and ArcCheckTM devices. Portal imaging devices are also employed with the inclusion of SNC EPIDoseTM analysis software. Assessment in the Transverse plane forms a key part in visualisation of the dose distribution discrepancies between plan and delivery and hence significantly increases user confidence in the validity of a particular treatment.

2

Bar Test (90cm SSD, 10cm Deep, 6MV FFF)

80

Pinnacle

70

Film Chamber

Absolute dose (cGy)

60 50 40 30 20 10 0 -10

-5

0 Distance oﬀ-axis (cm)

5

10

Methods and Materials: Radiochromic film GAF EBT2TM or EBT3TM was placed in the transverse plane of an IBA ImRTTM phantom. Radiotherapy VMAT treatment plans were generated on an Elekta MonacoTM TPS. The treatment delivery system was an Elekta SynergyTM. The ion chambers used for PDM were IBA cc04, used in either the IBA ImRTTM phantom or the ArcCheckTM device. The diode device for PDM was the central diode of the SNC MapCheckTM device. The Portal imaging device was the Elekta iViewTM. For all arrays of data, the final comparison of the measured data with the calculated data from TPS was achieved using the SNC PatientTM application. Results: The method presented is demonstrated to achieve an accuracy of 4%/2 mm. This is validated in comparison with other independent methods, PDM, array device measurement and Portal device measurement. We present results for Pre-treatment SBRT VMAT dosimetry. The dose range is 10–30 Gy. Conclusion: This method provides a practical and convenient method for the use of Radiochromic film in Pre-treatment QA of SABR treatments using VMAT.

Fig. 1. Bar test results for 6MV at 10 cm deep showing film measurements and Pinnacle calculations. The maximum difference between calculated (Pinnacle) and measured TSRs over a range of areas (16–900 cm2) and depths (1.6–20 cm) was found to be 5%) weight loss in patients receiving chemotherapy-RT for non-small cell lung cancer (NSCLC). Methods: Inclusion criteria for patient data included pathological NSCLC, concurrent chemotherapy and radical or high dose palliative RT between 03/04 and 08/07 and patient weight data (RT commencement day 0–90). Exclusion criteria included previous thoracic RT, RT alone and hyper-fractionated RT. The outer muscular oesophagus was delineated from the cricoid to the gastro-oesophageal junction (Focal, Computerized Medical Systems CMS, St Louis, MO, USA). Xio (CMS) dosimetric data were derived from 3DCRT plans, including oesophageal length and volume, maximum and mean doses. Chi-squared tests, Pearson correlation and individual logistic regression were used to examine associations. Results: Data of 50 patients were eligible for inclusion. The prevalence of clinically significant weight loss was 22% (median weight loss 9.1%, range 5.9–22.1). Dosimetric factors associated with >5% weight loss included maximum oesophagus dose (r = .33, p = .02), relative oesophageal volume receiving 40 Gy (r = .29, p = .04) and 60 Gy (r = .32, p = .03), absolute oesophageal length receiving 40 Gy (r = .32, p = .03), 50 Gy (r = .36, p = .01) and 60 Gy (r = .45, p = .001) and relative oesophageal length receiving 50 Gy (r = .32, p = .02) and 60 Gy (r = .44, p = .001). The odds ratio of >5% weight loss were 1.18 (95%CI 1.01,1.37, p = .04), 1.20 (95%CI 1.03,1.41, p = .02) and 1.32 (95%CI 1.09,1.60, p = .005) greater for patients receiving 40 Gy, 50 Gy or 60 Gy, respectively to the partial circumference (median length 10.6 cm, 10.2 cm, 7.2 cm, respectively). Conclusion: The strongest association was absolute oesophageal length receiving 60 Gy to the partial circumference. These data will be used, with data from a similar study investigating patient and clinical factors associated with weight loss, to develop and validate a model to predict lung cancer radiotherapy patients at high nutritional risk.

Aim: Current imaging protocol utilised for treatment verification of radical lung patients involves Radiation Therapists (RT), Advanced Practice Radiation Therapists (AP-RT) and Radiation Oncologists (RO). The aim of this survey was to formally review the understanding all RTs have of this soft-tissue imaging protocol, and to assess workflow efficiency within this practice. Method: Following ethics approval, a prospective audit of 250 RTs across five sites of Peter MacCallum Cancer Centre was conducted using anonymous online survey platform, Survey monkey©. Eligibility to complete the survey included fully qualified RTs who had at least three months experience with the imaging technique within the last five years. Results: 61 (24%) RTs were eligible to participate and responded to the survey. 45 (74%) were qualified more than five years, and all grade classifications were represented. 23 (38%) participants rated themselves as having a confidence level greater than eight (out of ten) in performing the soft-tissue match. Significant factors contributing to lack of confidence were uncertainties concerning the complexity of the match (29 RTs, 48%), and lack of experience (20 RTs, 33%). 32 (52%) respondents identified the primary issue concerning workflow was delayed review of images by the ROs. Of the 10 (16%) RTs who indicated hesitancy regarding performing the soft-tissue image match, seven indicated that the treating RTs role was to notify the AP-RT that the soft-tissue image was available for review. Conclusion: This audit identified that measures are required to improve the efficiency of workflow surrounding the radical lung imaging protocol. The dissemination of results will guide the definition of role responsibilities, and the development of documentation and training to help equip staff to confidently perform the soft-tissue image matching process. Review is also to be conducted of the communication tools utilised between stakeholders, to expedite workflow and create consistency across sites.


Scientific Exhibits The use of Varian Delta Couch Shift functionality during treatment set-up: A radiation therapists’ perspective K Faulkner Central Coast Cancer Centre, New South Wales, Australia

227 Can the compact economical Nano-X linear accelerator system be a solution for improving access to radiotherapy globally? P Lazarakis, E Eslick, I Feain and P Keall Radiation Physics Laboratory, The University of Sydney,

Aim: To determine the radiation therapists’ perspective on using the Varian Delta Couch Shift functionality for automatic isocentre positioning during a patient’s radiation therapy treatment set-up. Method: From April 2013 the Central Coast Cancer Centre (CCCC) introduced the Delta Couch Shift functionality for all treatment sites excluding breast, extremity, electrons and fixed techniques. In August 2013, in an attempt to reduce isocentre set-up documentation discrepancies, all brain patients were trialled without isocentre instructions written in the set-up notes. The treatment isocentre position was located solely by using the Delta Couch Shift from the reference marks placed on the mask at CT. In October 2013 a survey of five questions was given to all radiation therapists at CCCC relating to their experience with the delta couch shift functionality. Results: A total of 17 out of 21 responses were returned. Overall the CCCC radiation therapists were comfortable with the delta only isocentre shifts for brain patients with 14 staff moderately or extremely comfortable with the technique. Eleven responses reported a reduction in errors or near misses for patients on this trial; however 5 therapists reported errors or inaccuracies with the Delta Couch Shift functionality including the couch not moving to isocentre or user error resulting in the Delta Couch Shift not being performed correctly. Ten therapists reported that in their opinion compliance with the timeout procedure had been affected for patients on this trial, and 11 were concerned about introducing delta only information for other sites. Conclusion: Overall radiation therapists were satisfied with the Delta Couch Shift functionality for automatic isocentre shift for patients undergoing brain radiation treatment at CCCC. This technique is being continued for brain patients, but has not yet been introduced for other sites until concerns over errors and inaccuracies are addressed. Training on appropriate timeout procedures has been provided for staff.

New South Wales, Australia Aim: 650,000 lives are lost every year due to the global shortage of 10,000 radiotherapy systems[1]. The situation is dire in the developing world, where 70% of the radiotherapy systems in use still rely on Cobalt therapy[2] and a further estimated 7000 systems are needed[2]. To address the global cancer radiotherapy shortage, we have invented the Nano-X, which utilises patient (not gantry) rotation to deliver a compact, economical linear accelerator. We have previously published[3] cost comparisons between NanoX and conventional linear accelerators, which is a valid comparison for the developed world where linear accelerators makeup 85% of radiotherapy machines. In this paper, we present a straightforward cost comparison between NanoX and Cobalt therapy systems, the latter that comprises 70% of radiotherapy machines in the developing world. Method: We compare machine and bunker costs for a Cobalt system to NanoX using the published cost of a Cobalt machine[2]. Bunker costs for Cobalt are calculated assuming similar shielding requirements to a conventional 4 MV linac system[3]. The NanoX bunker has been costed by [3]. The company building the NanoX prototype has provided us with an estimated cost to build a production version NanoX. Results: The NanoX machine and bunker is estimated to cost approximately half that of a Cobalt system. In 2014 dollars, the approximate cost of a Cobalt machine and bunker (830 k + 500 k) is about double that estimated for a mass produced NanoX (500 k + 150 k). Conclusion: There is an urgent need for more cancer radiotherapy systems. The NanoX is a compact, economical cancer radiotherapy device to address global inequities in access to treatment. NanoX retains all the sophisticated imaging and tracking modalities of conventional and modern linear accelerators. We have shown that its expected cost (machine and bunker) will be approximately half that of a Cobalt therapy system. References [1] Varian Medical Systems, Year End Review 2011. [2] WHO World Cancer Report 2003. [3] Eslick E, Keall PJ. 2014. The Nano-X linear accelerator: a compact and economical cancer radiotherapy system incorporating patient rotation. Technol Cancer Res Treat, in press.


228 Iodine distribution maps for evaluation of suspected pulmonary embolism in patients undergoing dual-energy CT pulmonary angiography: a pictorial review S Figar, A Gisik, J Pratap and J Coucher Princess Alexandra Hospital, Queensland, Australia

Scientific Exhibits Inter- and intra-fraction motion in stereotactic body radiotherapy for spinal and paraspinal tumours using cone beam computed tomography and positional correction in six degrees of freedom R Finnigan,1 B Lamprecht,1 K Jones,2 T Barry,1 J Boyd,1 B Burmeister3 and M Foote3

Aim: We present the range of appearances encountered in a large cohort of patients undergoing dual-energy computer tomography (DECT) pulmonary angiography (CTPA) with iodine distribution mapping for investigation of suspected pulmonary embolism (PE) at our institution. Method: A retrospective review was performed of all patients who underwent second-generation dual-source dual-energy CTPA at a major teaching hospital in Brisbane. All patients were undergoing clinically-indicated CTPA for diagnosis or exclusion of PE. Patients who were acutely short of breath at the time of scanning were excluded, given the slightly longer acquisition time of the dual energy protocol. Scans were acquired with tube voltages of 100- and 140-kVp. Images were reconstructed as pulmonary iodine distribution maps (as a surrogate measure of pulmonary perfusion) and weighted fused images (resembling the usual 120 kVp CTPA image) using proprietary algorithms supplied by the CT system manufacturer. Results: We present a range of paired images (iodine distribution maps and weighted fused images) of acute and chronic PE, consolidation, atelectasis, interstitial lung disease, normal anatomical variants, and common artefacts. Conclusion: DECT with iodine distribution mapping provides functional as well as morphological information. This has clinical utility in the investigation of suspected PE by improving ease of detection and reader confidence.

1

Princess Alexandra Hospital, 2Translational Research

Institute, 3University of Queensland School of Medicine, Princess Alexandra Hospital, Queensland, Australia Aim: Stereotactic body radiotherapy (SBRT) for spinal and paraspinal tumours involves the delivery of high biological equivalent doses in a small number of fractions to targets in close proximity to the spinal cord or cauda equina. With high doses per fraction and steep dose gradients, small changes in patient position can confer significant dosimetric impact on adjacent structures.1 This study analyses target positioning error in consecutively treated patients on a strict image-guidance protocol with on-line correction in 6 degrees of freedom (6-DOF). Method: Set-up error, residual error after image-guided correction, and intra-fraction motion for 30 courses of spinal SBRT in 27 patients were assessed using cone beam computed tomography (CBCT). Positional error was corrected in 6-DOF (x, y and z translational planes and rotational axes) using a robotic couch, applying 2 mm and 2° action levels. A linear mixed-effects model was used to assess whether positional error was influenced by factors such as vertebral level, immobilisation device, and treatment duration. Results: Sixty-two fractions were delivered with 225 image registrations. Method of immobilisation varied according to level of spinal involvement. Median duration of treatment was significantly longer for patients treated with static field intensity modulated radiotherapy compared to volumetric arc treatment – 40 min versus 28 min respectively (p = 0.0045). Across all fractions, the median residual positional error after initial correction was greatest in the x translational plane (0.5 mm; 95% CI 0.3–0.6) and y rotational axis (0.25°; 95% CI 0.1–0.3). Median intra-fraction error was also greatest in the x-plane (0.7 mm; 95% CI 0.5–1.0) and y-axis (0.4°; 95% CI 0.2–0.5). Excluding one outlying patient with inadequate pain control, the mean intra-fraction motion (±SD) was up to 0.9 mm (±0.6) and 0.5° (±0.7). Conclusion: Even with strict immobilisation, image-guidance and 6-DOF correction, our results caution against reduction of planning margins for target volumes and critical structures to below 3 mm. Reference 1. Wang H et al. Dosimetric effect of translational and rotational errors for patients undergoing image-guided stereotactic body radiotherapy for spinal metastases. Int J Radiat Oncol Biol Phys 2008; 71(4): 1261–71.


Scientific Exhibits

229

Technique and early clinical outcomes for spinal and paraspinal tumours treated with stereotactic body radiotherapy R Finnigan,1 B Burmeister,2 T Barry,1 K Jones,3 J Boyd,1 1

2

Head and neck squamous cell cancer: imaging game-changers in staging and management V Francis,1 C Liu2,3 and E Lau1,3 1

Cancer Imaging Department, Peter MacCallum Cancer

R Williams and M Foote

Centre, 2Radiation Oncology Department, Peter MacCallum

1

Cancer Centre, 3University of Melbourne, Victoria, Australia

Princess Alexandra Hospital, 2University of Queensland

School of Medicine, Princess Alexandra Hospital, 3

Translational Research Institute, Queensland, Australia

Aim: Stereotactic body radiotherapy (SBRT) involves the precise delivery of highly conformal and image-guided hypofractionated external beam radiotherapy. Large doses per fraction result in high biologic equivalent dose to the tumour, whilst steep dose gradients and accurate target localisation minimise surrounding normal tissue toxicity. SBRT is increasingly being applied in the management of spinal tumours.1,2 Local technique and early clinical results are reported. Method: Patient characteristics, plan dosimetry and clinical outcomes for all patients treated with SBRT for spinal/paraspinal disease at this institution were reviewed. Mann–Whitney and two-tailed Fischer’s exact tests were used to compare clinical/dosimetric parameters with outcomes of survival, local relapse and pathological compression fracture (CF). Results: Thirty-six courses of spine SBRT in 34 adult patients were delivered between May 2010 and December 2013. Mean patient age was 58 years. Treatment was predominantly for metastatic disease (commonly melanoma, prostate and breast). SBRT was applied in de-novo, re-treatment and post-operative settings. Prescribed doses included 20 Gy/1#, 24 Gy/2-3#, and 28 Gy/2-3#. Technique evolved during the study period, from static intensity modulated radiotherapy prescribed to a reference point, to volumetric arc radiotherapy prescribed to a covering isodose. Planning goals, dose constraints, and target coverage are described. No CTCAEv3.0 grades III-IV acute toxicity were observed. At median follow-up of 7.4 months (range 1.7–22.2), no late radiation myelopathy was observed. Risk of new/ worsening CF was 22% (n = 8), which was significantly associated with SINS score (p = 0.0002). In-field control was 86%, with relapse occurring at a median of 2.8 months post-treatment. Local failure was accompanied by distant relapse in most cases. Thirteen (36%) patients have died and median overall survival for the group has not yet been reached. Conclusion: SBRT is an evolving technology with promising early efficacy and safety results. Our outcomes are comparable with international literature, with longer follow-up awaited.

Purpose: Head and neck squamous cell carcinoma (HNSCC) imaging poses several challenges as the anatomy is complex, the tumours are at times difficult to identify and tumour staging is site specific. Correctly identifying imaging ‘game-changers’ can fundamentally alter clinical decision making with regard to the modality of treatment (surgery, radiotherapy or chemotherapy) or the treatment intent (curative vs. non curative). This educational exhibit will review the American Joint Committee on Cancer (AJCC) 7th edition staging system for head and neck squamous cell carcinoma and highlight game-changing imaging features in their staging and clinical management. Content: • Outline the AJCC 7th edition TNM staging system for HNSCC • Describe the concept of imaging ‘Game-changers’ in the context of staging and management of HNSCC • Specific imaging ‘Game-changers’: Ë Size matters Ë T4 tumour features Ë Primary tumour lateralisation-well lateralised vs. crossing the midline Ë Perineural spread patterns Ë Nodal disease – unilateral vs. bilateral and extra-capsular extension Ë Where to look for ‘unknown primary’ lesions Ë Distant metastatic disease and the role of whole body PET/CT Conclusion: Imaging plays a key role in the staging and clinical management of head and neck squamous cell carcinoma. This exhibit will emphasise the ‘game changing’ imaging features that have a major impact on tumour staging and management decisions.

References 1. Sahgal A, Larson D, Chang E. Stereotactic body radiosurgery for spinal metastases: a critical review. Int J Radiat Oncol Biol Phys 2008; 71(3): 652–65. 2. Yamada Y, Lovelock DM, Bilsky MH. A review of image guided intensity-modulated radiotherapy for spinal tumors. Neurosurgery 2007; 61: 226–35.


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Scientific Exhibits

Acute cervical extradural haematoma: diagnosis as an unexpected finding on CT J Freebody,1 D Markan,1 J Evans,2 R Lee,1 B O’Brien,2

Seven-year diagnostic radiology audit results at a principle referral and regional trauma centre J Freebody, K Marripudi, D Markan and M Baillie

D Crimmins2 and J Hanson1

Medical Imaging Department, Gosford Hospital, New South

1

Medical Imaging Department, Gosford Hospital, 2Neurology

Wales, Australia

Department, Gosford Hospital, New South Wales, Australia Aim: Spontaneous acute cervical extradural haematoma (ACEH) is a rare emergent condition which may mimic more common clinical syndromes.1,2 Although more readily appreciated on MRI, ACEH can be diagnosed on CT/CTA if relevant imaging features are sought.3 We aim to present three cases where CT showed the clinically unexpected finding of ACEH, and to review the spectrum of imaging findings. Method: Case studies: Patient 1: 82-year-old man (therapeutically anticoagulated) presented with neck pain and rapidly progressive, asymmetrical incomplete quadriparesis. Patient 2: 67-year-old man (therapeutically anticoagulated) presented with acute neck and interscapular pain followed by right limb weakness. Patient 3: 63-year-old man (receiving clopidogrel) presented with acute neck and interscapular pain followed by subjective right limb heaviness. Results: Patient 1: CTA aorta/carotid circulation showed no major arterial abnormality. There was high-density posterolateral extradural collection from C3-C7, consistent with ACEH. A small focus of iv contrast enhancement (“spot sign”) was identified representing active haemorrhage. MRI confirmed ACEH. Laminectomy and haematoma evacuation was performed. Following a complicated recovery he was discharged for rehabilitation. Patient 2: CTA aorta/carotid circulation showed no dissection. Spinal extradural haematoma was present from C2-C5. MRI confirmed ACEH. The patient underwent laminectomy and haematoma evacuation, with improvement of neurological deficit and subsequent discharge for rehabilitation. Patient 3: CTA aorta demonstrated a high-density extradural collection, with thecal effacement and cervical cord compression. MRI confirmed ACEH. The patient was managed conservatively and discharged without neurological deficit. The presence of ACEH was initially unexpected in each of these cases, and early diagnosis was facilitated by systematic review of CT/CTA images. A review of the imaging findings in this condition will be presented. Conclusion: The differential diagnosis of acute neck or chest pain with neurological features should include ACEH, which may be identified early by CT/CTA.

Aim: Retrospectively assess diagnostic errors and associated modalities that were presented for discussion at regular Gosford Hospital radiology audit meetings over a seven-year period. Method: Gosford Hospital is a 484-bed institute which serves a population of over 320,000 residents.1 It provides medical care for all specialties apart from cardiothoracic and neurosurgery, and comprehensive imaging services apart from nuclear medicine. As a quality assurance initiative within the Gosford Hospital radiology department regular audit meetings are held and a selection of diagnostic errors discussed. Referrals are made voluntarily by radiologists or clinicians who recognise errors during their daily work or through discussion at multidisciplinary meetings. Prior to the meeting each radiologist involved with an individual case is notified, a report addendum made and the referring clinician contacted where appropriate. These meetings aim to encourage open reporting and the discussion of errors, and to promote cultural change and quality improvement. A retrospective review of data prospectively collected from June 2006 to March 2014 was undertaken. Sufficient data for assessment was available for 262 cases. Collected information included the specific error involved, imaging modality and error type (perceptual or interpretative). Results: Of 262 diagnostic errors, 201 (77%) were perceptual and 61 (23%) were interpretative. CT was the most frequently involved modality, comprising 202 (77%) of all errors. Of these, 155 (77%) involved scans of the abdomen and pelvis, with missed gastrointestinal masses, significant bone lesions and free intraperitoneal air being the most common perceptual errors. Plain radiography was the next most frequent modality and comprised 34 (16%) of all referrals. 19 (56%) of these involved missed lung nodules. Conclusion: In keeping with published reports,2,3 most errors presented at our audit meetings were perceptual. False negative errors during CT-AP interpretation accounted for most error referrals. References 1. NSW Ministry of Health. NSW Health Annual Report 2012–2013; [cited 2014 March 19]. Available from: http://www.health.nsw.gov .au/publications/publications/annualreport13/annualreport13.pdf 2. Donald JJ, Barnard SA. Common patterns in 558 diagnostic radiology errors. J Med Imaging Radiat Oncol 2012; 56: 173–8. 3. McCreadie G, Oliver TB. Eight CT lessons that we learned the hard way: an analysis of current patterns of radiological error and discrepancy with particular emphasis on CT. Clin Radiol 2009; 64: 491–9.

References 1. Adamson DC, Bulsara K, Bronec PR. Spontaneous cervical epidural hematoma: case report and literature review. Surg Neurol 2004; 62: 156–60. 2. Shin JJ, Kuh SU, Cho YE. Surgical management of spontaneous spinal epidural hematoma. Eur Spine J 2006; 15: 998–1004. 3. Lobitz B, Grate I. Acute epidural hematoma of the cervical spine: an unusual cause of neck pain. South Med J 1995; 88: 580–2.


Scientific Exhibits An overview of Electronic tissue Compensation (ECOMP) for breast radiotherapy M Friend William Buckland Radiotherapy Centre Gippsland

231 Assessing the activity of Crohn’s disease G Noe,1 A Galvin,2 M Goodwin1 and S Esler1 1

Austin Hospital, Melbourne, Victoria, Australia, 2St Vincent’s

Hospital, Melbourne, Victoria, Australia

(Traralgon), Victoria, Australia Aim: To provide an overview of Electronic tissue Compensation, (ECOMP), by exploring current literature as well as clinical perspectives from William Buckland Radiation Oncology (WBRO). Method/Background: Breast cancer is the most common occurring cancer and leading cause of cancer death in Australian women, with approximately 13,000 women diagnosed annually1. Standard treatments include conservative surgery, chemotherapy and whole breast irradiation. Conventional radiotherapy is administered with two tangential beams using wedges and segments to improve dose homogeneity. However, due to the steep contour changes in breast tissue dose homogeneity can be difficult to achieve, especially in women with a large separation. Results: Literature has demonstrated how Intensity Modulated Radiation Therapy, (IMRT), can improve dose homogeneity and have the added benefit of reducing dose to the lung and heart2. An IMRT technique, utilised at both the WBRO centre’s (The Alfred and Traralgon), is Electronic tissue Compensation (ECOMP). This is a forward planning process which is efficient, improves dose homogeneity to the breast and reduces both planning and treatment times3. Conclusion: ECOMP is a viable and clinically beneficial solution to dosimetric difficulties that can arise in breast radiotherapy. ECOMP it utilised at both WBRO campuses to improve dose homogeneity and reduce planning and treatment times. ECOMP is not widely employed and literature citations are limited. However, clinical experiences with the technique are positive and point toward an exciting future. WBRO has begun expanding the use of ECOMP to other sites of the body such as axilla and as a substitute for lead blocking in the mantle technique. References 1. Cancel Council Australia. Breast Cancer [homepage on the internet]. [updated 2013 July; cited 2013 Nov 20]. Available from: http://www.cancer.org.au/about-cancer/types-of-cancer/breast -cancer.html 2. 1.Peulen H, Hanbeukers B, Boersma L et al. Forward intensitymodulated radiotherapy planning in breast cancer to improve dose homogeneity: feasibility of class solutions. Int J Radiation Oncology Biol Phys 2012; 82(1): 394–400. Available from: http://www.ncbi .nlm.nih.gov/pubmed/21036489 3. Caudell JJ, De Los Santos JF, Keene KS et al. A dosimetric comparison of electronic compensation, conventional intensity modulated radiotherapy, and tomotherapy in patients with early-state carcinoma of the left breast. Int J Radiation Oncology Biol Phys 2007; 68(5): 1505–11. Available from: http://www.ncbi.nlm.nih.gov/ pubmed/17674981

Aim/Learning Objectives: We aim to demonstrate to the reader the importance of accurate assessment of disease activity of Crohn’s disease and the premier role MRI plays in the assessment of disease activity. 1,2 We also aim to enable the reader to perform an assessment of disease activity on MRI by using key MRI signs of active and inactive disease. Background: Assessing disease activity in patients with Crohn’s disease is a complex task, but is vital for treatment planning by the clinician and to guide them in their use of immune-modulating, biologic and surgical therapies. Imaging and in particular MRI plays an increasing role in the assessment of disease activity. Method/Imaging Findings: In a stepwise approach with examples from MRI small bowel studies performed at our institution we aim to demonstrate and discuss common and validated key signs seen in the different stages of disease activity. Some of these signs are stratified enhancement, comb sign, bowel wall oedema, restricted diffusion and fibrotic strictures. 3,4 By using these key signs we have subdivided the disease activity in 2 groups: active and inactive disease and we have outlined a simplified and structured approach to assessing disease activity in small bowel MRI studies in patients with Crohn’s disease. Results: Not applicable. Conclusion: In this stepwise pictorial review, referenced to the literature, we have demonstrated that MRI is the premier tool in assessing disease activity in patients with Crohn’s disease. Assessing disease activity is complex and there is a lot of overlap between active and inactive disease, but when a simplified and structured approach is applied using key MRI findings this can be a much easier task. References 1. Yacoub JH, Obara P, Oto A. Evolving role of MRI in Crohn’s disease. J Magn Reson Imaging 2013; Jun; 37(6): 1277–89. 2. Griffin N, Grant LA, Anderson S et al. Small bowel MR enterography: problem solving in Crohn’s disease. Insights Imaging 2012 Jun; 3(3): 251–63. 3. Neubauer H, Pabst T, Dick A et al. Small-bowel MRI in children and young adults with Crohn disease: retrospective head-to-head comparison of contrast-enhanced and diffusion-weighted MRI. Pediatr Radiol 2013 Jan; 43(1): 103–14. 4. Punwani S, Rodriguez-Justo M, Bainbridge A et al. Mural inflammation in Crohn disease: location-matched histologic validation of MR imaging features. Radiology 2009 Sep; 252(3): 712–20.


232 The complications of Crohn’s disease part one: The complications of acute and chronic intestinal disease A Galvin,1 G Noe,2 M Seale1 and Sutherland1 1

St Vincent’s Hospital, 2Austin Health, Victoria, Australia

Aim: Crohn’s disease is an idiopathic inflammatory disorder, which can affect any part of the gastrointestinal tract. The aim is to illustrate the manifestations and complications of active transmural inflammation and ulceration as well as the complications of chronic, relapsing disease. To describe the spectrum of complications related to perianal Crohn’s disease and finally to outline the post-operative complications of Crohn’s patients and the morbidity related to recurrent bowel resections. Method: A review of the literature supplemented with case examples from the author’s institution, to illustrate the spectrum of complications related to Crohn’s enteritis and perianal disease. Results: The initial presentation and acute flares of active Crohn’s disease manifest predominantly with small bowel obstruction as well as complications of transmural disease such as perforation, intraperitoneal and retroperitoneal abscess formation, sinus and fistula formation. In chronic relapsing Crohn’s disease, the predominant patterns are fistulising disease and fibrostenotic disease. Perianal Crohn’s disease is associated with significant morbidity and is difficult to treat. Associated complications include ischioanal and pelvic sepsis, genitourinary fistulas, as well as pelvic osteomyelitis. Post operative complications are also an important feature of Crohn’s disease, as close to 50% of patients will have undergone an operation within 5 years of diagnosis. In addition to the usual risks of abdominal surgery, such as anastomotic leak, postoperative collections and hernia formation, Crohn’s disease can also be complicated by anastomotic recurrence and short gut syndrome related to excessive bowel resection. Conclusion: The complications related to transmural inflammation and ulceration in Crohn’s disease are varied and a significant cause of morbidity. Knowledge of these complications is important for all Abdominal and General Radiologists to aid the planning of medical and surgical therapies.

Scientific Exhibits The complications of Crohn’s disease part two: Extra-intestinal manifestations and associations A Galvin,1 G Noe,2 M Seale1 and T Sutherland1 1

St Vincent’s Hospital, 2Austin Health, Victoria, Australia

Aim: The extra-intestinal associations of Crohn’s disease are extensive, with involvement of many body systems. The aim is to illustrate the spectrum of extra-intestinal associations, with particular emphasis on the hepatobiliary and genitourinary systems. This poster also aims to provide examples of rare extra-intestinal manifestations of Crohn’s disease, and finally to highlight the increased risk of malignancies in Crohn’s patients. Method: A review of the literature as well as cases from the author’s institution, to provide a pictorial review of the extra-intestinal associations of Crohn’s disease. Results: The most common extra-intestinal association of Crohn’s disease is enteropathic arthropathy, which tends to precede the onset of gastrointestinal disease and progresses independently. Cholelithiasis and nephrolithiasis are also common and relate to different pathways of malabsorption. Other extra-intestinal associations include dermatological and respiratory disease as well as mental health disorders. Rare extra-intestinal manifestations are that of cutaneous Crohn’s disease and mass forming Crohn’s disease in organs such as the kidney, liver and pancreas. Crohn’s disease is associated with increased risk malignancy, with statistically significant increased rates of small bowel adenocarcinoma, colorectal carcinoma and extraintestinal lymphoma. The final extra-intestinal association of Crohn’s disease is immunosuppression and the subsequent complications that can arise, particularly with the use of biologic agents. Conclusion: The spectrum of extra-intestinal manifestations and associations of Crohn’s disease is vast and varied. It is important to be aware of these associations and document any relevant findings when reporting abdominal imaging studies, as they can have important implications for treatment and prognosis.


Scientific Exhibits

233

Point spread dose kernel distortion by in-line and perpendicularly aligned magnetic fields typical of MRI-linacs M Gargett,1 B Oborn,1,2 P Metcalfe1,3 and A Rosenfeld1

Intensity Modulated Radiation Therapy (IMRT) for patients with primary endometrial cancer: using volumetric imaging to cover what counts P Gautam

1

Epworth Radiation Oncology, Victoria, Australia


Wollongong, 2Illawarra Cancer Care Centre, Wollongong Hospital, 3Ingham Institute of Applied Medical Research, Liverpool Hospital, New South Wales, Australia Aim: To observe the perturbation of dose kernels in different density media due to the presence of in-line and perpendicularly aligned magnetic fields, for consideration in MRI-linac dose planning and verification. Method: Point spread dose kernels were produced using the Monte Carlo simulation toolkit, GEANT4 version 9.6.p02. Kernels were generated from a unidirectional pencil beam with photon spectrum based on a 6 MV beam model from a Varian 2100C linear accelerator (model verified previously).[1] Only particles originating from a 1 mm3 voxel were tracked. Dose kernels were generated in silicon (ρ = 2.33 g/cm3), water (ρ = 1 g/cm3) and low-density lung (ρ = 0.3 g/cm3) to cover a range of typically encountered densities. The effect of uniform magnetic fields of strength 0.5 T, 1 T, 1.5 T and 3 T were investigated for both in-line and perpendicularly aligned field orientations (w.r.t. photon beam). The 0 T case was also simulated for comparison. Results: The spread of dose from the point source in silicon has been plotted in figure 1, normalised to maximum dose (note the logarithmic scale). The kernels demonstrate a clear shift in dose, corresponding to the change in trajectory of dose depositing secondary electrons in the direction of the associated Lorentz force. By comparison, the perturbation is exacerbated in the lower density materials, water and lung.

% of max. dose

(a) B = 0T

(b) B|| = 1T

(c) B = 1T

(d) B|| = 3T

(e) B = 3T

Aim: The clinical uptake of bladder and bowel preparation guidelines in conjunction with volumetric imaging for patients receiving IMRT for gynaecological cancers is relatively low when compared with prostate cancer practices. This paper will analyse a unique online image matching process using daily pre-treatment Cone Beam CT (CBCT) to assess critical structure and target volume displacement for patients with primary endometrial cancer undergoing radical IMRT. Method: Patients are instructed for simulation and treatment to fill their bladder by drinking 500–750 mls of fluid and empty their rectum to minimise target volume displacement and reduce small bowel dose. The influence of the critical structure size and position in relation to primary and nodal target volumes are assessed in real time – overlaying the structure outlines derived from the planning CT scan with the daily CBCT and making online corrections accordingly. Results: Comparison of planning CT and CBCT images showed the effects of bowel and bladder motion on target volumes are extremely variable. To account for these variations, it is justifiable to primarily base daily treatment matching upon zero tolerance, assessing bony anatomical structures in conjunction with soft tissue placement ensuring primary disease is covered. In our experience, it has been observed that the validity of planned treatment volumes depends on the consistency of rectum and bladder preparation guidelines. Noticeable trends in filling have also been observed at various time points throughout the course of radiotherapy. Conclusion: A unique daily online image matching process for primary endometrial cancer patients undergoing radical IMRT allows therapists to assess the placement of target volumes relative to rectum and bladder filling. Daily CBCT assessment is done to apply online corrections based on bony anatomical matching in conjunction with soft tissue position. The daily variation in bowel and bladder preparation is thus accounted for in treatment delivery.

Fig. 1. Dose kernels in silicon for in-line and perpendicular magnetic field alignments. Conclusion: Dose kernel distortion should be taken into account in treatment planning systems that use convolution methods when implementing MRI-guided radiation therapy for both in-line and perpendicularly aligned magnetic fields. Results for silicon are helpful when considering the use of solid state detectors, e.g. EPID, for which magnetic fields above 1 T have an influence on the trajectory of dose depositing electrons; albeit small compared to that of lower density media. Reference 1. Oborn BM, Metcalfe PE, Butson MJ, Rosenfeld AB. High resolution entry and exit Monte Carlo dose calculations from a linear accelerator 6 MV beam under influence of transverse magnetic fields. Medical Physics 2009 July 2; 36(No 8): 3549–59.


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Scientific Exhibits

The implementation of PEARL 3D visualisation software to augment radiation therapy patient education sessions J Gilshenan,1 K Williams,1 M Ind1 and D Willis1,2

Educational modules for appropriate imaging referrals: Point of care tools for the emergency department S Goergen1,2,3 and J Grimm3

1

1

North West Cancer Centre Tamworth, New South Wales, 2

Australia, Beam Kids Melbourne, Victoria, Australia

Department of Diagnostic Imaging, Monash Health, Victoria,

Australia, 2Monash University, Department of Surgery, Southern Clinical School, Clayton, Victoria, Australia, 3The

Aim: Misconceptions or a lack of knowledge about Radiation Therapy processes can compound the anxiety patients experience at the commencement of treatment. This paper describes the implementation of 3D visualisation software to augment pre-planning patient education sessions. Method: The PEARL (VERTUAL, Hull UK) visualisation software displays radiation therapy datasets in an interactive 3D representation of a treatment bunker. Reference datasets or the patient’s own data can be displayed and incorporated into patient education delivery. Use of PEARL for demonstration of the patient’s own treatment delivery was reserved for specialised cases such as non-coplanar brain. Patient education videos were produced that incorporated both actual footage and PEARL simulations to demonstrate generic treatment processes. Video content was based on published needs and existing patient education materials. Patient review was undertaken prior to clinical use. Videos were incorporated into pre-planning education sessions. Patient surveys were conducted to ensure that video content remains appropriate. The surveys included questions as to whether the PEARL visualisation was useful in describing the processes. Results: The process of exporting a patient’s dataset from the planning system to PEARL can be completed in less than 10 minutes. Displays of the patient’s own anatomy, particularly surface anatomy can be confronting. Generic information videos were more commonly utilised than patient specific datasets. Evaluation of the effectiveness of PEARL visualisation within the videos is ongoing. Conclusion: It is feasible to incorporate aspects of 3D visualisation software into patient education delivery. The effectiveness of using this delivery tool is still being analysed.

Royal Australian and New Zealand College of Radiologists, New South Wales, Australia Aim: To demonstrate point of care tools for evidence based decision making about imaging of emergency patients. Methods: The Educational Modules for Appropriate Imaging Referrals Project was funded by a grant from the Australian Government Department of Health. A detailed summary of the methods employed in the project are provided in this electronic exhibit including: 1. Systematic search of the medical literature for decision tools/risk assessment strategies • Appraisal of resulting scientific material • Production of summary tables for each clinical condition 2. Development of educational modules (EMs) content by multidisciplinary writing groups for each topic • Content includes:

∘ Performance of individual CDRs ∘ Application of CDRs to practice using algorithmic approaches ∘ Clinical scenarios that test application of the EM content by the student to real life situations 3. Multidisciplinary writing groups applied the outcomes of the literature reviews to the clinical setting. This has resulted in the development of 10 EMs • Introduction to CDRs • Acute head trauma (adult and paediatric) • Acute cervical spine trauma (adult and paediatric) • Acute ankle and foot trauma (adult and paediatric) • Suspected pulmonary embolism (pregnant and non pregnant) • Suspected lower limb deep venous thrombosis • Acute low back pain Results: As well as web based electronic modules, an important output of this project are the one page, point of care tools that summarise the more detailed information within the modules to enable efficient use of the information at the point of care. The imaging algorithms for each of the conditions above are provided in this exhibit along with detailed description of the project methodology that resulted in these algorithms. Conclusion: Brief point of care tools that meet the needs of the end user increase the likelihood that more detailed clinical decision support information will be used in practice.


Scientific Exhibits

235

Evaluating the impact of the 2013 radiation oncology trainee survey on education initiatives P Gorayski,1 M Lehman,1 A Windsor,2 B Heggelund3 and

The 3 Rs of mitigating burnout in radiation oncology trainees: rest, recovery, relaxation and support P Gorayski and M Poulsen

S Turner4

Mater Radiation Oncology Centre, Queensland, Australia

1

Princess Alexandra Hospital, Queensland, Australia,

2

Central Coast Cancer Centre Gosford Hospital, New South

Wales, Australia, 3The Royal Australian and New Zealand College of Radiologists, New South Wales, Australia, 4Crown Princess Mary Cancer Centre Westmead, New South Wales, Australia Aim: To evaluate the efficacy of the first Radiation Oncology Trainee Committee (ROTC) survey on influencing education initiatives proposed by the Trainee Resource Executive (TRE) of the Royal Australian and New Zealand College of Radiologists (RANZCR). Method: One hundred and fifty two radiation oncology trainees were surveyed in June 2013 in the first combined ROTC and TRE online survey. Opinion was sought regarding ROTC awareness, collaboration between RANZCR and the European Society for Therapeutic Radiology and Oncology (ESTRO), the utility of the RANZCR learning management system (LMS), and interest in a proposed live education course. Results: One hundred and eighteen responses were received (74% response rate). By January 2014, the results of the survey were used in multiple RANZCR committee meetings. The ROTC had adopted a policy of regular correspondence amongst its constituents to improve awareness and representation. One hundred and four (88%) trainees were aware of the resources afforded to them by the ESTRO-RANZCR affiliate membership and 44/118 (37%) had participated in Fellowship in Anatomic Delineation and Contouring (FALCON) or live courses. One hundred and three (87%) trainees said they were interested in participating in online interactive ‘tutored’ FALCON in the future and all supported further ESTRO teaching courses coming to Australia and New Zealand. As a result, ESTRO-RANZCR collaboration was formally strengthened for enhanced cross-organisational cooperation with educational resources. LMS use had increased from 40/118 (34%) surveyed trainees to 76/148 (51%) registered trainees as of January 2014, and a working party was established to improve its utility. A working party was also established to develop a proposed live course on the basis of high interest regarding its usefulness. Conclusion: RO trainee surveys significantly impact on decision making regarding RANZCR education initiatives. Periodic surveys conducted by ROTC are recommended to assess trainee opinion on issues relating to vocational training.

Aim: Radiation Oncology (RO) trainees are required to juggle the emotional burden of looking after cancer patients as well as the demands of study. Recovery experience (RE) and social support (SS) are measurable and negatively associated with burnout. We applied the findings from a large cross-sectional study of cancer workers to current RO trainee demographics and ask how these findings might relate to trainees. Method: A cross-sectional survey of 573 cancer workers in Queensland was conducted with a response rate of 56%. 53% of the workforce was aged >35 years and 80% were female. RE and SS were measured using a validated questionnaires and multiple regression analyses (MRA) were performed to examine explanatory variables independently associated with SS. Results: As of December 2013, 147 trainees were enrolled in the RANZCR RO training program (mean age 32.2 years), and 68/147 (46%) female. 79.8% were undertaking training in an RA1 (major city) training centre, 13.5% in a RA2 (inner regional) centre, and 6.7% in an RA3 (outer regional) centre, using the ASGC-RA classification. There was a negative correlation between the RE score and burnout (p = 0.002), psychological distress (p < 0.0001) and age above 25. Participating in strenuous exercise was associated with high RE Scores (p = 0.015). Exhaustion (a component of burnout) was inversely associated with SS on MRA (p < 0.001). Working in a regional cancer centre was correlated with better support. Workers older than 25 years were more likely to report a lack of their superiors talking about their work than their younger counterparts. Conclusion: RE and SS are negatively associated with burnout in cancer workers. Trainees need to factor in recovery and SS strategies into their lives to diminish risks of burnout. To optimise performance, trainees are encouraged to build support networks at work and at home and consciously incorporate recovery strategies such as exercise into their daily routines.


236

Scientific Exhibits

The ‘A Career in Radiation Oncology’ project: Process, resources and outcomes M Grand,1 S Cronjé,1 C Dempsey,2 A Dry,3 R Hill,4

CT guided thermal ablation of recurrent lung cancer in patients post radiotherapy. A case series review S Gray

L McGhee,5 M Najim,6 J Page4 and P Taylor1

Royal Brisbane and Womens’ Hospital, Queensland,

1

Australia

The Royal Australian and New Zealand College of

Radiologists (RANZCR), Sydney, New South Wales, Australia, 2Department of Radiation Oncology, Calvary Mater Hospital Newcastle, Newcastle, New South Wales, Australia, 3

Department of Radiation Oncology, Royal Brisbane and

Women’s Hospital, Brisbane, Queensland, Australia, 4

Department of Radiation Oncology, Lifehouse, Royal Prince

Alfred Hospital, Camperdown, New South Wales, Australia, 5

Liz Plummer Cancer Care Centre, Cairns Base Hospital,

Cairns, Queensland, Australia, 6Department of Radiation Oncology, Princess Margaret Cancer Carer Centre, Westmead Hospital, Westmead, New South Wales, Australia Aim: The ‘A Career in Radiation Oncology’ (ACIRO) Project aimed to promote radiation oncology (RO) as a career option, focusing on all three specialties of RO including radiation oncologists, radiation therapists and radiation oncology medical physicists. The aim was to develop a set of resources to be used for career promotion, to attend career events throughout Australia and distribute these resources. The objectives were to build an awareness of RO and the disciplines that provide RO services, increase the number of suitably qualified RO professionals and influence career planning decision-making at an early age. Method: Funding was secured from the Australian Government Department of Health. The ACIRO project was overseen by a Steering Committee whose membership included representatives from all three associations of the Tripartite. The target audience for career promotion was careers advisors, high school and university students. The careers resources used to promote ACIRO included a brochure, five videos, website, Facebook page, Twitter page, posters, advertisements, and presentation. Members of the profession attend careers events in major capital cities and regional locations to promote RO careers. A student seminar program was developed in conjunction with scientific meetings as well as being held in regional RO departments. Results: 59 career events were attended in 2013 and 50 events were attended or are being attended in 2014. Student seminars were held three times in conjunction with scientific meetings and in three regional RO departments and were attended by high school and university students, careers advisors and parents. Careers resources were used to promote the profession and the website and YouTube videos have experienced regular traffic. Conclusion: These events have generated positive feedback from both attendees and RO professionals. The RO community is being encouraged to utilise the resources produced as a strategy to continue promote a career in RO.

Objectives: Lung cancer is the most common cause of cancer related mortality in the western world. For local disease, the standard treatment is surgical resection; however, at least 20% of patients are unable to have surgery due to medical comorbidities. Current practice for non operable, early stage, non-small cell lung cancer involves external beam radiotherapy. A significant number of patients who undergo radiotherapy develop tumour recurrence and have relatively low 5 yr survival rates of 10–30%. Traditionally, patients who had tumour recurrence had limited treatment options consisting of chemotherapy or other methods of palliation. The aim of this study is to retrospectively evaluate survival, local tumour regression and complication rates for percutaneous CT guided thermal ablation (radiofrequency or microwave ablation) performed on patients for tumour recurrence post external beam radiotherapy at a tertiary cancer hospital. Materials & Methods: Between 2008 and 2012, seven patients were selected for thermal ablation who had previously been diagnosed with non-small cell lung cancer and which was initially treated with external beam radiotherapy. At the time of presentation for thermal ablation they had local tumour recurrence or new limited intra-pulmonary metastatic disease and were not deemed suitable for further radiotherapy or surgery after discussion at the pulmonary malignancy MDT meeting. Clinical outcomes were determined on the basis of review of medical records, follow up imaging and any biopsy proved residual or recurrent disease (if available). The primary outcomes of survival and time to tumour recurrence post ablation were analysed using the Kaplan– Meier method, which enabled construction of survival and disease recurrence curves. Results: The overall 1, 2 and 3 year survival rates [ ], [ ] and [ ]%. Four out of seven patients developed tumour recurrence following the initial ablation necessitating a second ablation. Of the four lesions that received a second ablation, no recurrence was seen. The local tumour progression free rates at 1 and 2 years were [ ] % and [ ]% respectively. The overall pneumothorax rate was [ ]% ( three out of eleven ablation sessions), chest tube insertion rate was [ ] % (one out of eleven ablation sessions). Conclusions: Both radiofrequency and microwave ablation yield encouraging results in patients with medically inoperable early stage lung cancer who have undergone external beam radiotherapy and who subsequently develop local tumour recurrence or limited metastatic disease.


Scientific Exhibits MITIE C-Arm – advanced innovation in education C Berry, V Braithwaite, G Mahoney, T Gunn, P Bridge, P Rowntree, D Starkey and K Wilson-Stewart Queensland University of Technology, Queensland, Australia

237 Optimal reconstruction phase of ECG-gated CT angiography in the diagnosis of acute thoracic aortic pathology (work-in-progress) D Hocking and A Gupta Fremantle Hospital, Western Australia, Australia

Aim: In 2013 QUT introduced the Medical Imaging Training Immersive Environment (MITIE) as a virtual reality (VR) platform that allowed students to practice general radiography. The system software has been expanded to now include C-Arm. The aim of this project was to investigate the use of this technology in the pedagogy of undergraduate medical imaging students who have limited to no experience in the use of the C-Arm clinically. Method: The Medical Imaging Training Immersive Environment (MITIE) application provides students with realistic and fully interactive 3D models of C-Arm equipment. As with VR initiatives in other health disciplines (1–2) the software mimics clinical practice as much as possible and uses 3D technology to enhance 3D spatial awareness and realism. The application allows students to set up and expose a virtual patient in a 3D environment as well as creating the resultant “image” for comparison with a gold standard. Automated feedback highlights ways for the student to improve their patient positioning, equipment setup or exposure factors. The students’ equipment knowledge was tested using an on line assessment quiz and surveys provided information on the students’ pre-clinical confidence scale, with post-clinical data comparisons. Ethical approval for the project was provided by the university ethics panel. Results: This study is currently under way and this paper will present analysis of initial student feedback relating to the perceived value of the application for confidence in a high risk environment (i.e. operating theatre) and related clinical skills development. Further in-depth evaluation is ongoing with full results to be presented. Conclusion: MITIE C-Arm has a development role to play in the pre-clinical skills training for Medical Radiation Science students. It will augment their theoretical understanding prior to their clinical experience. References 1. Bridge P, Appleyard R, Ward J, Phillips R, Beavis A. The development and evaluation of a virtual radiotherapy treatment machine using an immersive visualisation environment. Computers and Education 2007; 49(2): 481–94. 2. Gunn T, Berry C, Bridge P et al. 3D Virtual Radiography: Development and Initial Feedback. Paper presented at the 10th Annual Scientific Meeting of Medical Imaging and Radiation Therapy, March 2013 Hobart, Tasmania.

Aim: Helical multi-detector row computed tomography (MDCT) has an established role in the diagnosis of acute aortic pathology. Motion-free visualisation of the aortic root and ascending aorta allows the radiologists to make a confident diagnosis and can aide with surgical planning. Retrospectively ECG-gated scans acquire complete data throughout the cardiac cycle and are reconstructed at a specified point in the R-R interval, significantly reducing motion artefact.1 Optimal reconstruction phase varies depending on the structure being evaluated and the patient’s heart rate. Current protocol at our institution is to reconstruct a 75% phase when the heart rate is less than 80 beats per minute (bpm) and a 40% phase for heart rates greater than 80 bpm; a practice which is based on operator experience. This project aims to evaluate the image quality of various reconstruction phases to develop a standardised, evidence-based protocol for departmental use. Method: All studies are performed on a single, 64-slice multi-detector row CT scanner. Consecutive, prospective studies performed on patients receiving retrospectively ECG-gated CT angiography of the thoracic aorta are included in the study. CT data are reconstructed at 10% increments between 20% and 80%, with additional phases at 35%, 45% and 75%. Subjective visual comparison of each phase is performed independently by the two investigators to determine the phase with the least motion artefact. A third party consensus is made on dis-concordant scores. Tabulated data comparing heart rate and optimal phase will be assessed. Results: Preliminary results on 14 patients suggests a 75–80% optimal phase at low heart rates (n = 7; HR < 60), while at high heart rates a 40–45% phase appears preferable (n = 7; HR > 60). Data collection is ongoing. Conclusion: Early data support a correlation between heart rate and optimal phase of reconstruction. Lower heart rates appear to be optimally reconstructed at later phases in the cardiac cycle, while faster rates may require earlier phase reconstruction. Reference 1. Roos JE, Willmann JK, Weishaupt D, Lachat M, Marincek B, Hilfiker PR. Thoracic aorta: motion artifact reduction with retrospective and prospective electrocardiography-assisted multi-detector row CT. Radiology 2002 Jan; 222(1): 271–7.

This project was possible due to funding made available by Health Workforce Australia.


238 CT imaging of complications associated with percutaneous non-vascular renal interventions S Halagatti Venkatesh and N Karaddi Singapore General Hospital, Singapore

Scientific Exhibits

5. Dominguez Bravo C, Soler Fernandez JM et al. Renal arterioveneous fistula, up-dated presentation of a new case. Actas Urol Espb 1991; 15(1): 46. 6. Moskowitz GW, Lee WJ, Pochaczywsky R. Diagnosis and management of complications of percutaneous nephrolithotomy.Crit Rev Diag Imaging 1989; 29(1).

Aim: 1. To identify the various complications associated with percutaneous non-vascular renal intervention and differentiate them. 2. To provide information which helps in deciding either conservative management or active intervention. 3. To provide accurate roadmap if active intervention is needed. Method: Patients referred for suspected complications associated with percutaneous non-vascular renal intervention and having various CT presentations have been included in this pictorial essay. Results: The various nonvascular percutaneous renal intervention include non-focal renal biopsy for nephropathies or transplant rejection, focal renal biopsies for tumours, cyst aspiration, tumour ablation and percutaneous nephrostomy for obstructed uropathy. Although relatively safe, complications are known to be associated with percutaneous intervention. Complications include bleeding, infection, and injuries to adjacent organ and injuries to pelvicalcyceal system or ureter. Bleeding may be due to injury to renal vessels, bleeding from vascular mass, arteriovenous malformation (AVM) or arteriovenous fistula (AVF). Patient may present either with haematuria or shock. Massive haematuria is usually as a result of renal AVF or AVM. In less severe cases it may be from venous source or necrotic kidney tissue. Mild perinephric haematoma is very common and selflimiting. Massive perinephric haematomas can also occur compressing renal parenchyma. The peripheral lumbar or intramuscular arteries may also be injured leading to bleeding. Injury to the pelvicalcyceal system may lead to leakage of urine resulting in urinoma formation. CT being non-invasive and faster with MPR in various vascular phases can easily identify the above complications. Associated adjacent visceral injury can also be assessed. It also helps in accurate interventional planning and further treatment. By providing quick diagnosis and with early treatment patient morbidity and mortality can be reduced. We will attempt to provide pictorial essay of various complications and help to differentiate various lesions on CT including perinephric haematoma, AVF, AVM, bleeding from peripheral lumbar or intramuscular arteries, urinoma, bleeding into pelvicalcyceal system, infections such as pyelonephritis and renal abscess. Conclusion: Various life threating complications may occur with percutaneous renal intervention and CT plays a vital role in identifying and helping in further management. References 1. Sivanandam SE, Mathew G, Bhat SH. Emerging role of multidetector computed tomography in the diagnosis of hematuria, following percutaneous nephrolithotomy: a case scenario. Indian J Urol 2009 Jul; 25(3): 392–4. 2. Mousavi-Bahar SH, Mehrabi S, Moslemi MK. Percutaneous nephrolithotomy complications in 671 consecutive patients. A single-center experience. Urol J 2011; 8: 271–6. 3. Mandal S, Sankhwar SN, Goel A. Is there a role of post percutaneous nephrolithotomy routine computer tomography scan to anticipate complication? Indian J Urol 2011; 27: 433–4. 4. Boschiero LB, Saggin P, Galante O et al. Renal needle biopsy of the transplant kidney: vascular and urologic complications. Urol Int 1992; 48(2): 130.


Scientific Exhibits

239

Development of benchmarking cases to assist early users commissioning of model based dosimetry calculation algorithms in brachytherapy treatment planning systems A Haworth,1,2 R Smith,3,4 F Siebert5 and L Beaulieu6,7 1

2

Peter MacCallum Cancer Centre, Sir Peter Mac

Real-time surveillance of eye position and gating for stereotactic radiotherapy of choroidal melanoma A Haworth,1,2 M Kenny,1 E Ungureanu,1 S Todd,1 M Wright,1 B Chesson,1 M Portillo,1 C Fox1 and C Phillips1 1

Peter MacCallum Cancer Centre, 2Sir Peter Mac

Department of Oncology, University of Melbourne,

Department of Oncology, University of Melbourne,

Melbourne, Victoria, Australia, 3William Buckland

Melbourne, Victoria, Australia

Radiotherapy Centre, The Alfred Hospital, Victoria, Australia, 4

Applied Physics, School of Applied Sciences, RMIT

University, Victoria, Australia, 5University Hospital of Schleswig-Holstein, Campus Kiel, Kiel 24105, Germany, 6

Cancérologie de l’Université Laval, Centre hospitalier

universitaire de Québec, Québec, Québec G1R 2J6, Canada, 7et d’Optique, Université Laval, Québec, Québec G1R 2J6, Canada Aim: Following the publication of recommendations for early users of model based dose calculation algorithms for brachytherapy (MBDCA)(1), the AAPM-ESTRO-ABG Working Group (WG) was commissioned to develop of a set of well-defined test case plans to assist clinical end-users of MBDCAs in the software commissioning process. We present the role of the Australasian Brachytherapy Group (ABG) in the development of these test cases and provide preliminary results of comparisons of test cases and a clinical case with conventional dose calculation methods(2). Method: Virtual, vendor independent, generic Ir-192 HDR source and shielded applicator models were designed by the WG with specifications for use with Monte Carlo codes and the two commercial treatment planning systems that offer MBDCAs. The ABG produced the defined test case plans using the collapsed cone (CC) kernel superposition algorithm from one of the commercial systems. In addition, clinical test cases including a prostate with gas in the rectum, was investigated. Results: Test cases that incorporated simple geometry demonstrated little difference in dose distribution between conventional and the CC algorithms (less than 1% in a plane perpendicular to the source up to a distance of 30 mm from the source). In contrast, the test case that incorporated a shielded applicator demonstrated significant differences around the edges of the shielding. The clinical case demonstrated minimal differences in the dose to the prostate, with variations in dose of less than 1% in the region between the posterior prostate and rectum. Conclusion: Dose distributions using the CC algorithm and the virtual source have been created for three test cases. The AAPM-ESTROABG WG will compare results from calculations of the test cases using a range of calculation methods to produce benchmarking data sets to assist local users in the commissioning of MBDCAs.

Aim: Develop a prototype system for stabilising and monitoring eye movements for simulation and treatment using a non-invasive technique for linac-based stereotactic radiotherapy (SRT) of choroidal melanoma. Method: A prototype system incorporating an LED diode for eye fixation and a mirror/camera system for monitoring was constructed based on the design of Petersch et al. (1) The system is used in conjunction with a head and neck mask system for immobilisation and uses infrared tracking technology for patient positioning prior to treatment (ExacTrac, BrainLAB AG, Feldkirchen, Germany). Use of the system within the 3T MRI required extensive shielding of metal components and replacement of the LED system for eye positioning using light transmitted from the in-room lighting system through a red filter. The system was used during CT and MR image acquisition as well as during all 2 Gy treatment fractions (6 MeV, 70 Gy to 80% isodose) to guarantee consistent patient setup and eye rotation. Results: High resolution MR images were acquired using a loop coil positioned over the affected eye. These images were fused with 1 mm CT axial slices using a field of view limited to the eye structures. The camera system displays live video images of the treated eye so that manual beam interruption can occur in the event of prolonged systematic deviation from the planned position, or unacceptable large random motion of the affected eye. Software is currently under development to automatically record and track the eye position during simulation and treatment enabling patient specific CTV-PTV margins to be created. Conclusion: The eye tracking and immobilisation system allows for accurate co-registration of the MRI and CT images for precise delineation of the target volume, with the potential to improve accuracy of treatment delivery compared with conventional treatment set-ups. Reference 1. Petersch B, Bogner J, Dieckmann K, Potter R, Georg D. Automatic real-time surveillance of eye position and gating for stereotactic radiotherapy of uveal melanoma. Med Phys 2004 Dec; 31(12): 3521–7.

References 1. Beaulieu L et al. Report of the Task Group 186 on model-based dose calculation methods in brachytherapy beyond the TG-43 formalism: current status and recommendations for clinical implementation. Med Phys 2012 Oct; 39(10): 6208–36. 2. Perez-Calatayud J et al. Dose calculation for photon-emitting brachytherapy sources with average energy higher than 50 keV: report of the AAPM and ESTRO. Med Phys 2012 May; 39(5): 2904–29.


240

Scientific Exhibits

Is extra corporeal shockwave lithotripsy (ESWL) more effective when conducted under general anaesthetic compared with conscious sedation?: a retrospective review J Hayes,1 C Grobler,2 C Frampton3 and S English4

Under-exposed: Bringing the request form into focus C Younger, D Buckley, B Charlton, J Frankel, S Frankel and

1

Aim: The medical imaging request form is part of the essential communication chain between medical practitioners, radiographers and other allied health professionals. Method: Thorough research and analysis of literary articles was conducted with the aim of addressing the issues associated with the medical imaging request. Results: From this research it was found that the inadequate completion of the medical request form can have a detrimental impact on patient care. Through the identification of common errors associated with the written request it becomes apparent that a comprehensive completion can fundamentally improve patient care by minimising radiation dose, reducing unnecessary examinations, and by narrowing the possible hypotheses for the radiological report. It is evident that the inclusion of a relevant, yet detailed clinical history will reduce confusion and miscommunication between medical departments, and hence allow for appropriate examination planning. This in turn, increases the likelihood of a correct diagnosis. It has been further concluded that a systematic and comprehensive request form design is essential. Conclusion: Recommendations have been made to address a range of short falls associated with the design of the imaging request and its completion. Optimally completed request forms have the capacity to increase efficiency among the different medical departments, to support a better use of resources and to reduce the occurrence of radiology associated medico-legal claims. This can dramatically improve the patient service, consequently improving patient care.

CPIT, 2Urology dept, Nelson Hospital, Nelson, New

Zealand, 3School of Medicine, University of Otago, New Zealand, 4Urology Dept, Christchurch Hospital, Christchurch, New Zealand Aim: To assess the efficiency of ESWL when it is conducted under general anaesthetic and conscious sedation. Success was no remaining fragment greater than 4 mm. Method: Data were collected from 6266 patients with a single primary non-staghorn calculi who were treated with a Dornier S1 or Dornier S2 lithotripter between June 1995 and December 2013. Stone size was analysed radiologically (KUB, CTU, or ultrasound) prior and post ESWL. Categories for treatment result were: No change, complete fragmentation, stone fragments remaining ≥4 mm, stone fragments remaining ≤4 mm. Two assessors were used for all analyses, a Radiologist report and an ESWL specialist Radiographer. Where disagreements arose a Urologist and additional Radiographer were called upon to help. SPSS v19 was used for these simulations and calculations. Results: The overall success rate for ESWL in this review was 68%. Success was no remaining fragment greater than 4 mm. The success rate for treatment under general anaesthesia was 70.2%, compared with 65.6% for treatment under conscious sedation, (p < 0.001) 60.8%(n = 3411) of patients received general anaesthesia during ESWL. Of those with a stone larger than 10 mm 59.6%(n = 1140) received general anaesthesia. Patients with stones 30 (p = 0.038) and higher ISS (p = 0.032). Conclusion: A significant percentage of cervical spine fractures identified on subsequent cervical spine CT are not visible on plain radiographs. There is also a high rate of technical inadequacy of cervical spine plain radiography in the modern Australian trauma population. These findings lend support to the use of cervical spine CT as the primary imaging modality in cervical spine clearance.


250 The dependence of CT-RED conversion on phantom geometry and its impact on patient dose E Inness,1 V Moutrie1 and P Charles1,2 1

Scientific Exhibits Breast screening – is mammography the answer? C Younger, E Inskip, J Pattie, P Oliver, D Hunt and C White University of Newcastle, New South Wales, Australia

Princess Alexandra Hospital, Woolloongabba, 2School of

Chemistry, Physics, and Mechanical Engineering, Queensland University of Technology, Queensland, Australia Aim: To test the influence of phantom geometry and scatter conditions on the CT to RED calibration, and to quantify how any differences affect the dose planned to the patient. Method: The CIRS Model 002LFC, CIRS Model 062, Gammex RMI467, Gammex tissue equivalent slabs, and inserts from the Gammex RMI-467 phantom (as standalone objects in air), were all scanned using a Toshiba Aquilion 16 LB CT scanner. A CT-RED calibration was obtained for each phantom, and the results were compared to the anthropomorphic CIRS Model 002LFC phantom. The effect of each calibration on planned dose to a patient was quantified using a commercially available treatment planning system. Results: Cortical bone gave a maximum CT number difference of 1110 when a cylindrical insert of diameter 28 mm scanned free in air was compared to that in the form of a 30 cm × 30 cm slab. The largest percentage dose difference was 8.3% which occurred when the CT-RED calibration curve was acquired with heterogeneity inserts scanned free in air. The maximum dose difference observed between two commercially available CT-RED phantoms was ±2.1%. Conclusion: The CT number of a material was found to depend strongly on the amount and type of scattering material surrounding the volume of interest, with the largest variation observed for the highest density material tested, cortical bone. A phantom that is to be used for CT-RED calibrations must have sufficient water equivalent scattering material surrounding the heterogeneous objects that are to be used for calibration.

Aim: Explore current breast screening initiatives and other potential modalities including Magnetic Resonance Imaging and Ultrasound, to investigate the benefit versus risk associated with each of these.1, 2 The role of the Radiographer was also examined to ascertain their involvement in successful imaging of the breast.3, 4 Method: An extensive data collection of relevant information and statistics from journals, research articles, imaging and modality reports as well as benefit and risk assessments. A critical appraisal of literature was performed on information sources to ensure its validity and its usefulness to this research. Analysis of data was then conducted in order to investigate the benefit versus risk associated with current breast screening initiatives. Results: While mammograms carry a potential risk of induced cancer, it operates within an acceptable benefit risk ration.1 The effectiveness of each modality is largely reliant on patient presentation and the ability of the radiographer to provide optimal diagnostic images in order to form correct diagnosis.5, 6 Conclusion: Mammography, Breast MRI and Ultrasound each have their own set of benefits and disadvantages, but when used in conjunction with each other, they provide the most accurate results.4, 7 References 1. Cancerscreening.gov [homepage on the Internet]. Breast Screen Australia Program [cited: 24 Aug 2013]. About the program. Available from: http://www.cancerscreening.gov.au/internet/screening/ publishing.nsf/Content/breastscreen-about) 2. Beckett J, Kotre C, Michaelson J. Analysis of benefit: risk ratio and mortality reduction for the UK breast screening programme. British Journal of Radiology 2003, May; 76(No 905): 309–20. 3. Kuhl CK. The current status of breast MR imaging part I. Choice of Technique, Image Interpretation, Diagnostic Accuracy, and Transfer to Clinical Practice Radiology 2007 Mar; 244 (No 2): 356–78. 4. Teh W, Wilson A. The role of ultrasound in breast cancer screening. A consensus statement by the European Group for Breast Cancer Screening. European Journal of Cancer 1998 May; 34 (No 4): 449-–50. 5. Mitka M. Researchers seek mammography alternatives. The Journal of American Medical Association 2003 July 23; 290(No 4): 450–1. 6. Cancerscreening.gov [homepage on the Internet]. BreastScreen Australia Program. [cited: 24 Aug 2013]. Screening – how do I arrange a mammogram? Available from: http://www .cancerscreening.gov.au/internet/screening/publishing.nsf/Content/ how 7. Shiwan K, Shah B, Greatrex KV. Current role of magnetic resonance imaging in breast imaging: a primer for the primary care physician. The Journal of the American Board of Family Practice 2005 Nov; 18(No 6): 478–90.


Scientific Exhibits

251

Accuracy of system-displayed radiation dose metrics used for patient dosimetry and/or radiation dose surveys M Irvine and T Ireland

Metal artefact reduction in head and neck imaging using dual-energy computed tomography and Metal Artifact Reduction Software A Jahangiri,1 J Coucher2 and J Pratap2

Queensland Health, Brisbane, Australia

1

Prince Charles Hospital, 2Princess Alexandra Hospital,

Queensland, Australia Aim: To investigate the accuracy of system-displayed radiation dose metrics that may be used for patient dosimetry or for conducting radiation dose surveys, across a number of Queensland Health (QH) sites. Computed tomography (CT), radiographic and fluoroscopic systems were investigated. Method: The volumetric computed tomography dose index (CTDIvol) was measured, using a polymethyl methacrylate CTDI body phantom and calibrated Unfors Xi CT dose meter, for an axial body scan on 16 CT systems, of various model, installed at QH hospitals. In each case, the measured CTDIvol was compared to the post-scan, systemdisplayed CTDIvol. The dose-area-product (DAP) was calculated from measurement of air kerma (X-ray tube side of the table, if applicable) with a calibrated Unfors Xi dose meter and area at the same plane, for 22 radiographic systems and 9 fluoroscopic systems, of various model, installed at QH hospitals. The measurements were made over a range of operating conditions (tube voltage, added filtration and field size) and compared to the displayed values. Results: The range in error of displayed CTDIvol varied considerably, between −22% and 15% (mean −1%, SD 10%). The range in error of displayed DAP also varied considerably, between −17% and 76% (mean 5%, SD 19%). Conclusion: The accuracy of system-displayed CTDIvol and DAP can’t necessarily be relied upon and should be checked as part of a routine quality assurance program. Calibration should be requested where limits are exceeded. If, following a routine dose-survey, a system appears to near or exceed the relevant local, national or international DRL, the accuracy of the displayed dose metric should be verified. Knowledge of errors in system-displayed dose metrics may also allow correction prior to use as inputs into dose surveys or patient dose calculations.

Aim: The aim of this study was to evaluate the usefulness of dualenergy computed tomography with Metal Artifact Reduction Software in reducing the artefacts in patients with metallic dental fillings while assessing the head and neck images. Method: 6 patients with metallic dental fillings who underwent dual source Computed Tomography (DECT) of head and neck selected from image database. Images were reconstructed with Metal Artifact Reduction Software (MARS) and axial images of the area of their metallic dental fillings were evaluated and the images were reviewed in terms of quality and diagnostic value and severity of beam hardening artefacts and they were scored subjectively by use of a 10 point scale. Results: Use of Dual Energy Computed Tomography with MARS can significantly reduce the artefacts in head and neck images and increase the diagnostic value and quality of the images. Conclusion: Dual Energy CT with MAR can reduce the metal-related artefacts from the dental fillings and provides better view and delineation of the surroundings and the area of study while evaluating the head and neck DECT images.

80%

20% 10% 0% -10% -20% -30%

60% 40% 20% 0% -20% Error in Reported CTDIvol (%)

Error in Reported DAP (%)


252 Prostate gold seed fiducial implantation by radiation oncologists: A report on feasibility C Jayaratne, A Brown and A Tan The Townsville Hospital, Queensland, Australia

Scientific Exhibits The use of CCD cameras in plastic scintillation dosimetry systems within radiation therapy treatment rooms: Managing exposure to transient radiation M Jennings1,2 and T Rutten1 1

Aim: The Townsville Cancer Centre is a regional centre treating about 150 prostate cancer patients per year. Without a Urologist or Radiologist able to perform prostatic fiducial marker implantation, our Radiation Oncologists were trained in the procedure in order to allow us to commence delivering image guided radiotherapy. We report on our experience in terms of complications and toxicities. Method: 127 patients were given questionnaires regarding their experience of the fiducial marker implantation, which asked about complications and pain experienced. 101 returned the questionnaire and were analysed. We compared our results with the literature and examined for factors influencing the rate of complication or the quality of the implant. Results: 5.9% of patients lost at least one fiducial between implantation and commencement of treatment. Men with history of prior transurethral resection of the prostate were more likely to lose a fiducial marker (27.8% vs 1.2%, p < 0.001). The incidence of haematuria (19.8%), rectal bleeding (7.9%), infection (0%) and urinary retention (0%) were consistent with published data. There was no difference in quality of implant or incidence of complications between the two implanting oncologists. Conclusion: Fiducial marker implantation by oncologists is safe and feasible, allowing image guided radiotherapy to be adopted in centres where there is limited availability of other specialists trained in such procedures.

Royal Adelaide Hospital, 2The University of Adelaide,

South Australia, Australia Background: The application of CCD cameras within treatment rooms for scintillation detection poses logistical advantages over alternative detection methods1. However, their utility is limited by their sensitivity to stray radiation, which manifests as noise ‘spikes’ in the recorded images. Aim: To categorise the effect of transient radiation noise on the image quality of CCD cameras operating in treatment rooms and to mitigate image degradation via lead shielding. Method: Experiments were undertaken to determine suitable lead thicknesses for each direction and to investigate spectral variations of the scattered radiation with direction and shielding. To investigate the overall shielding effects, a CCD camera was placed on the treatment couch approximately 1 metre from the isocentre, with a large slab of solid water placed in the beam to provide adequate scatter (see Figure 1). Dark images were taken for various shielding configurations. For each configuration, the spike density, height and radius were analysed in order to encompass the overall improvement in image quality.

Fig. 1. Experimental setup.

Results: Relatively small thicknesses of lead substantially improve image quality. A marked 71% decrease in the affected pixel density was observed for 2 mm of lead shielding. Smaller improvements in image quality of 27–36% per additional 2 mm increment were observed (see Figure 2). The spikes’ heights and radii were also observed to moderately decrease with increasing thickness of lead shielding, however this is highly sensitive to the choice of threshold pixel value for the analysis.


Distorted pixels (× 103)

Scientific Exhibits

253

15

Civco Universal couchtop template script for the Pinnacle TPS C Jones, S Liu and B Harris

10

Princess Alexandra Hospital, Queensland, Australia

5 0 0

2 mm 4 mm 6 mm 8 mm No Rad

Thickness of lead shielding Fig. 2. Image quality vs. degree of shielding.

Conclusion: A conservative lead shielding thickness of 2 mm serves to considerably improve the image quality for CCD cameras exposed to stray radiation within a treatment room. The use of impractical amounts of lead is not necessary to obtain a satisfactory outcome. The energy spectrum of the scattered radiation is also a considerable factor. The combined use of image processing techniques may further improve image quality. Reference 1. Archambault L, Briere TM, Beddar S. Transient noise characterization and filtration in CCD cameras exposed to stray radiation from a medical linear accelerator. Med Phys 2008 September 20; 35(No 10): 4342.

Aim: The purpose of this work is to enable Pinnacle3 (v9.4) to accurately calculate transmission through the Civco Elekta Universal Couchtop. This is achieved by importing a model of the couchtop onto the primary data set in the TPS via a Pinnacle script. Method: The script was based on existing couch template code1. Modifications to the original script were the points defining the contour of a transverse slice of the couchtop, and the technique used to copy the contour of one slice onto the entire primary data set. The points defining the couchtop’s contour were located by displaying a transverse slice of a CT image of the couchtop on a computer screen, then defining the contour via the mouse. This method of generating the contour points was implemented in Matlab. The override density of the couchtop was selected by comparing measured and TPS calculated attenuation through the couchtop (keeping the density of the interior air at the original value of 0.02 g/cm2), then adjusting the override density to improve agreement. Transmission measurements were performed with an ion chamber in an IBA IMRT Phantom. Results: The table below compares measured and Pinnacle calculated transmission through the Civco couchtop (density override = 0.61, couch shell thickness = 4 mm).

Field size (cm x cm)

10 × 10

Gantry angle

180 150 130 110

6 MV transmission factor

10 MV transmission factor

Meas.

Calc.

Diff. (%)

Meas.

Calc.

Diff. (%)

0.979 0.971 0.956 0.952

0.975 0.972 0.956 0.951

–0.43 0.02 –0.01 –0.19

0.984 0.980 0.966 0.967

0.980 0.978 0.965 0.959

–0.42 –0.25 –0.11 –0.75

Conclusion: The resulting novel couch template script enables TPS transmission calculation within an accuracy of 0.5%. References 1. MedPhys Files; [updated 2008 May 19; cited 2014 March 24]. Patient Table in Pinnacle TPS. Available from: http://medphysfiles.com/ index.php?name=Downloads&file=details&id=33


254

Scientific Exhibits

Qfix Access Prone™ breast devices commissioning S Liu, C Jones, V Moutrie and T Barry

To determine optimum calibration method of EBT3 film C Jones and K Biggerstaff



Aim: Large-breasted patients are difficult to set up consistently in the traditional supine position because the breast may lie in different positions daily. With the prone breast setup, it may be possible to reduce the dose to nearby normal tissues for patients undergoing whole breast radiotherapy, and setup can be more reproducible. The Qfix Access ProneTM breast devices were commissioned for these treatments. Method: The treatment beam transmission and surface dose for 6 MV and 10 MV photon energies were measured and compared to Pinnacle planning system values. Two prone breast boards were CT scanned to check the uniformity of the material. Two test plans were generated and exported to the in-house independent MU check program for TPS dose verification. To have uniform dose across the whole breast, a simple two field step and shoot forward plan was planned with the breast device and dose verification was done. Results: Breast device transmission for 6 MV and 10 MV were 98.0% and 98.5%, respectively. The skin dose beyond the breast device was 91.6% and 81.8% of the maximum dose for 6 MV and 10 MV, respectively. The devices were uniform and did not cause any image artefacts. The breast devices tested were found to be identical. Dose verification was within 3% tolerance for all prone breast plans. Conclusion: The Qfix Access ProneTM Breast Devices were successfully commissioned for prone breast treatments. The Qfix Access ProneTM breast device causes negligible attenuation and is closely modelled by Pinnacle with the outside-patient air threshold of 0.6. Also, typical beam arrangements would mostly avoid passing through the structure. If a posterior field transits the board, an escalation of dose at the body surface will occur due to the build up. If uniform dose distribution is required, a simple two field forward step and shoot prone breast plan can be used.

Aim: The purpose of the work is to determine the optimum channel (red, green, blue, or a combination thereof) for calibration of EBT3 film for dose verification of radiotherapy plans. Method: EBT3 film calibration squares irradiated during QA of VMAT and stereotactic plans were analysed. Five forms of raw data from digitised (72 dpi, EPSON EXPRESSION 10000 XL) EBT3 film were compared: the individual red (R), green (G) and blue (B) channels; the average of the red and green (R+G) channels; and the average of the red, green and blue (R+G+B) channels. The sensitivity was defined as the change in pixel value per unit change in dose. Using the assumption that the signal-to-noise ratio (SNR) of calibration data is proportional to the square root of the number of combined channels, the measured sensitivity of the R+G channel was scaled by sqrt(2) and the R+G+B channel by sqrt(3). Results: For single channel data, the R channel was most sensitive for absorbed dose below 4–5 Gy, while the G channel was optimum for irradiation above this value. Combining channels increases sensitivity over all dose ranges with the R+G channel being most sensitive in the lower dose range (below 4–5 Gy), and R+G+B for higher doses. Conclusion: Combining data from R, G and B channels increases the sensitivity of the EBT3 dose versus pixel value calibration curves. It is recommended to use the combined R+G channel for typical IMRT/ VMAT treatments of approximately 2 Gy per fraction, and to use the combined R+G+B channel for hypofractionated and stereotactic treatments.


Scientific Exhibits

255

Implementing Australia’s first MRI simulator E Juresic,1 G Liney,1,2,4 L Cassapi,1 L Holloway1–5 and A Xing1 1

Liverpool Cancer Therapy Centre, 2Ingham Institute, 3

Liverpool Hospital, New South Wales, Australia, Institute of

Evaluating the sensitivity of common IGRT systems to intra-fraction motion of the vertebrae T Kairn,1,2 B Sutherland1 and N Middlebrook1 1

Genesis Cancer Care Queensland, Australia, 2Queensland

University of Technology, Queensland, Australia

Medical Physics, School of Physics, University of Sydney, New South Wales, Australia, 4Centre for Medical Radiation Physics, University of Wollongong, Wollongong, New South Wales, Australia, 5South Western Sydney Clinical School, University of New South Wales, Sydney, New South Wales, Australia Aim: Traditionally, radiation therapy patients have a CT Simulation prior to starting their treatment. If the Radiation Oncologist required more soft tissue information, the patient would be required to have an MRI done in radiology or at an external location. If the patient had already had an MRI completed at the beginning of their diagnosis, they would not be able to have another scan free of charge. If the patient had a prior MRI scan, these were often performed in a different position to that achieved for their treatment making fusion difficult. Method: Liverpool Cancer Therapy Centre had a 3T Siemens Skyra installed in June 2013. This is Australia’s 1st Radiation Therapy MRI Simulator. It is the first 3T MRI Simulator in the world. Coils and sequences were tested and commissioned to determine baseline levels and accuracy of each coil and sequence. Coils commissioned include: • 32 channel spine coil, • 20 channel brain coil, • 18 channel body array and • Small and medium flex coils. It was important to determine which sequences would need to be run on the various anatomical sites in order to give our radiation oncologists the best images possible while keeping our patients’ in their treatment position. Standard sites for MRI Simulation sites include: • Prostates, • Head and neck, • Brain, • Gynae and • Rectum. Lung and breast patients are also scanned for research purposes. Many challenges were faced and dealt with during this process, which will all be discussed in the presentation. Conclusion: A small group of radiation therapy staff received training in MRI Simulation for the Siemens Applications specialist. Sequences and coils were correctly tested and implemented. A large portion of our radical patients that have a CT Simulation the a MRI Simulation, where they are safely scanned. Staff and patients are screened prior to entering the room.

Aim: In order to accurately deliver modulated radiotherapy treatments to spinal metastases, while strictly limiting the doses to the spinal cord, a high degree of patient positioning accuracy and precision is required. This study evaluated the ability of three common radiotherapy imaging and fusion systems to detect and reproducibly measure small shifts in vertebral bony anatomy. Method: An MV EPID-based orthogonal imaging system (Varian, Palo Alto, USA), a kV EPID-based orthogonal imaging system (Varian) and a non-orthogonal kV x-ray system designed for stereotactic radiosurgery (Brainlab, Feldkirchen, Germany) were each used to repeatedly acquire images of a pelvis phantom containing sacrum and lumbar vertebra. The images were auto-matched with planning DRRs, with and without small orthogonal displacements in the phantom’s position. Results: The orthogonal MV and kV images showed precipitous gradients in pixel values at the superior and inferior edges of individual vertebrae, causing the orthogonal imaging systems to be very sensitive to longitudinal shifts in the phantom position. The standard deviations in the kV EPID system’s measurement of 1 mm lateral and longitudinal shifts were, respectively, 0.5 mm and 0.3 mm. The MV EPID system was consistently able to detect longitudinal shifts as small as 1 mm, but identified 2 mm lateral shifts only when no other simultaneous shifts were applied. The non-orthogonal stereotactic imaging system was more sensitive and produced more reproducible results, measuring 0.5 mm vertical, lateral and longitudinal shifts accurately, to within 0.1 mm, even when those shifts were applied simultaneously. Conclusion: This study suggests that high-precision modulated spinal treatments may be accurately deliverable without the use of implanted fiducial markers, if a kV imaging system, preferably a non-orthogonal system designed for stereotactic-level precision, is utilised. This work should be extended to evaluate the precision with which automated couch movements can account for the anatomical shifts detected by radiological imaging.


256

Scientific Exhibits

Experienced-based management of IMRT quality assurance T Kairn,1,2 S Crowe,2 B Sutherland,1 N Middlebrook,1 B Hill1 and J Trapp2 1

Genesis Cancer Care Queensland, Australia, 2Queensland

Current usage and diagnostic value of ultrasound as a first line investigation compared with serum biochemistry in the assessment of pyloric stenosis in a tertiary paediatric hospital J Karpewycz and L Fender

University of Technology, Queensland, Australia

Princess Margaret Hospital, Western Australia, Australia

Aim: This study uses the detailed, bulk analyses of a set of treatment planning and quality assurance data from one radiotherapy centre to provide an illuminating example of the provision evidence-based advice on the management, and potential reduction, of an IMRT quality assurance workload. Method: Crowe et al.’s TADA code1 was used to evaluate metrics describing plan accuracy and beam deliverability2, from DICOM RT PLAN data, for the IMRT treatments detailed below.

Aim: To determine the efficacy of ultrasound as a first line investigation for pyloric stenosis and its value in the context of normal serum biochemistry. Method: All abdominal ultrasounds performed between 2010 and 2012 on children aged less than 26 weeks with clinical suspicion of pyloric stenosis at our institution were evaluated. Each report was categorised as normal, pyloric stenosis, pylorospasm or inconclusive. Presentation biochemistry was assessed on those patients with pyloric stenosis. Medical records were assessed to determine outcome. Results: The current usage and outcomes of ultrasound are outlined in table one.

Site

No. of plans No. of beams

Prostate Brain Anus/ Head/ Endometrium Total rectum neck 30 210

10 56

6 79

3 22

3 35

52 402

The treatments were planned using the Varian Eclipse treatment planning system and verified using the EpiQA system3. Correlations between the accuracy and deliverability metrics and the quality assurance results (gamma pass rates) for these treatments were investigated, with a view to providing a set of conditions under which the quality assurance testing of future treatment plans could be reduced. Results: Generally, the anus, rectum, head and neck treatment beams were found to be more complex, with modulated fluences produced by combining larger numbers of small field apertures, than the prostate, endometrium and brain treatment beams. Statistically significant trends were identified in the data, with gamma pass rates decreasing with increasing beam modulation, increasing aperture variability, increasing proportions of MLC leaves crossing the central axis (increasing aperture asymmetry) and increasing proportions of small apertures in the beams. For example, all beams in which fewer than 20% of MLCs were open by less than 10 mm achieved high gamma pass rates and were approved for use in patient treatments. Conclusion: The results of this study suggest that, in this instance, comprehensive quality assurance testing of prostate and brain treatments comprised of beams with low modulation and with few MLC apertures narrower than 10 mm may be unproductive and that a re-examination of the local requirement to complete such testing would be advisable. References 1. Crowe SB, Kairn T, Middlebrook N et al. Retrospective evaluation of dosimetric quality for prostate carcinomas treated with 3D conformal, intensity-modulated and volumetric-modulated arc radiotherapy. Journal of Medical Radiation Sciences 2013 Nov 19; 60(4): 131–8. 2. Kairn T, Crowe S B, Kenny J, Knight R T, Trapp J V. Predicting the likelihood of QA failure using treatment plan accuracy metrics. Journal of Physics: Conference Series 2014 Mar 24; 489: 012051. 3. Nicolini G, Fogliata A, Vanetti E, Clivio A, Cozzi L. GLAaS: an absolute dose calibration algorithm for an amorphous silicon portal imager. Applications to IMRT verifications. Medical Physics 2006; 33(8): 2839–51.

Table 1. Number of ultrasound studies performed by year, n (% of year and total) Year

Normal

Pyloric stenosis

Pylorospasm

Inconclusive

Total

2010 2011 2012 Total

75 (67.6) 84 (70.6) 80 (65.6) 239 (67.9)

29 (26.1) 29 (24.3) 29 (23.8) 87 (24.7)

4 (3.6) 5 (4.2) 12 (9.8) 21 (6.0)

2 (1.8) 2 (1.7) 1 (0.8) 5 (1.4)

111 119 122 352

No patient with a normal pylorus developed pyloric stenosis on subsequent imaging. All patients with pyloric stenosis underwent pyloromyotomy. In eighteen patients with pylorospasm, seven had a normal pylorus demonstrated on subsequent imaging. Five had pyloric stenosis on repeat imaging. No pyloromyotomy was performed unless a study confirmed stenosis. Seventy-four patients with pyloric stenosis had biochemistry performed at presentation. Forty-five (61.6%) patients had elevated bicarbonate. Twenty-eight patients (37.8%) were alkalotic. Twenty-six of the 28 also had elevated bicarbonate. Nine patients (12.3%) had hypokalaemia. All nine were alkalotic with elevated bicarbonate. 27 (36.5%) patients had normal serum biochemistry and a positive diagnosis of pyloric stenosis on ultrasound subsequently confirmed at surgery. Conclusion: Ultrasound demonstrated pyloric stenosis in approximately 25% of patients with clinical suspicion. Ultrasound diagnosed pyloric stenosis in more than one third of patients prior to the development of biochemical abnormalities secondary to persistent vomiting and dehydration. Ultrasound is a useful, non-invasive first line investigation for pyloric stenosis and can detect clinically significant stenosis prior to biochemical abnormalities. The early detection of pyloric stenosis before the onset of electrolyte imbalance reduces patient morbidity, and potentially expedite time to surgery and reduce hospital stay.


Scientific Exhibits

257

Yield of biliary brushings in biliary strictures during Percutaneous Transhepatic Cholangiography (PTC) B Khoo, J Chong and J Tibballs

A radiation therapist perspective on the Australian Clinical Dosimetry Service [ACDS] level III audit C Knipe

Sir Charles Gairdner Hospital, Western Australia, Australia

Royal Hobart Hospital, Tasmania, Australia

Aim: To assess the percentage yield of biliary brushings in biliary strictures based on sensitivity and specificity in a single centre study. Method: The study was conducted as a retrospective cohort study. From November 2007 to June 2013, a total of 45 patients, who had brush cytology performed at Percutaneous Transhepatic Cholangiography (PTC) with the Rx Cytology Brush BILIARY (Boston Scientific – Spencer) in Sir Charles Gairdner Hospital, were included in this study. Patients were searched via the Qdoc database and final histopathology of the brushings were reviewed on the ICM Manager software, then analysed for specificity and sensitivity. Results:

Aim: To describe the radiation therapy process undertaken and the impact on the radiation therapist [RT] involved in the ACDS level III audit of the Royal Hobart Hospital Radiation Oncology Department. Method: The ACDS conducted level III audits of linear accelerators across Australia in the final phase of a three year pilot study that was a joint initiative of the Australian Government (Department of Health [DoH]) and the Australian Radiation Protection and Nuclear Safety Agency [ARPANSA]. In 2013 the Royal Hobart Hospital Radiation [RHH] Oncology Department participated in this audit. The level III audit involved the staff normally associated with the patient’s radiation oncology journey through the facility. At each step of the audit the radiation therapists undertook their routine role such as the CT simulation, planning on the facility’s treatment planning system, quality assurance processes and finally the treatment. Results: While the focus for the ACDS was on the dosimetric outcome of the audit based on the planning computer accuracy in predicting the dose they measured, the effect on the Radiation Oncology Department was broad. The audit raised both the confidence of the staff in the clinical work that they were engaged in and reinforced the importance of the radiation therapist role in auditing. The audit protocol included feedback to the ACDS which enabled the RT staff to comment and advise on the protocol, this was appreciated by the RT staff. Conclusion: The ACDS level III audit involved numerous members of the radiation oncology department who are frequently at the receiving rather than participating end of such programs. As such, the audit has raised the awareness of quality assurance within the department through participation. This involvement was appreciated by the RHH radiation therapists as a potential quantifiable improvement to patient safety.

Table 1. Analysis of biliary brushings during PTC Variable Brushed during PTC Total malignant based on final brushing histology 1. In-room cytology atypical/negative 2. In-room cytology positive 3. No in-room cytology, but histology sent Total equivocal based on final brushing histology 1. Follow-up with further imaging and subsequent histology positive 2. Follow-up with further imaging and subsequent histology negative Total negative based on final brushing histology 1. Follow-up with further imaging and subsequent histology positive 2. Follow-up with further imaging and subsequent histology negative Sensitivity of biliary brushings Specificity of biliary brushings

Number (%) 45 24 (53%) 6 (13%) 8 (18%) 10 (22%) 9 (20%) 4 (9%) 5 (11%) 12 (27%) 4 (9%) 8 (18%) 75% 100%

Conclusion: Our data show a 100% specificity and relatively high sensitivity of biliary brushings for malignancy in biliary strictures. Biliary brushing at time of PTC correctly identified 75% of malignant strictures. Subsequent imaging and histological techniques identified the remaining 25% malignant lesions. This suggests in-room brush cytology has a high predicting value for diagnosing malignant strictures and can be used to direct metal stent insertion.


258

Scientific Exhibits

Teaching radiology key conditions: new e-learning tutorials with local and international feedback H Knipe,1 J Runciman,1 M Paks,2 Y Ren,2 P Phal1,2 and

The introduction of e-learning into post-graduate radiology training in Fiji H Knipe,1 I Rouse2 and P Scally3,4

Gaillard1

1

1

Radiology Department, The Royal Melbourne Hospital,

Victoria, Australia, 2Fiji National University, Fiji, 3University of

2

Department of Radiology, University of Melbourne, Victoria,

Queensland, Queensland, Australia, 4Royal Brisbane and

Radiology Department, The Royal Melbourne Hospital,

Australia

Women’s Hospital, Queensland, Australia

Aim: To develop, distribute and receive feedback on an online platform for first-year Key Condition tutorials and assess current teaching methods. Method: Twenty-two sets of pre-learning modules and tutorials were developed, which fulfill RANZCR’s Key Condition curriculum, using an e-learning platform developed by Radiopaedia.org. Participants were given access to a pilot module and results were assessed via two surveys addressing current Key Condition teaching methods, the pilot module and existing online resources. Results: A survey was distributed to accredited radiology registrars in Australia and New Zealand (n = 387) with 79 responses recorded. Of Australian and New Zealand respondents, 82% received key condition teaching prior to on-call, with strong criticism of the current e-learning platform (R-ITI), with only 14% of respondents agreeing/strongly agreeing that R-ITI delivers quality and relevant educational material in an easy-to-use and access format. In contrast, there was a positive response to our pilot with 64% agreeing/strongly agreeing they would use this resource for preparing for Key Condition tutorials; 75% and 69% agreeing/strongly agreeing they would recommend this resource to first-year registrars and their departments respectively. A separate survey was distributed internationally via social media with 1450 responses, 444 being from radiology trainees. Of trainees surveyed worldwide, 35% of respondents stated they received teaching in emergency radiology core conditions prior to on-call. Again, a positive response was recorded with 75% agreeing/strongly agreeing they would use this resource for preparing for tutorials and 77% agreeing/ strongly agreeing they would recommend this resource to first-year registrars and their departments. Conclusion: We have successfully developed an online resource of pre-reading modules with cases and tutorials to be used for delivery of Key Condition teaching. Our pilot has received a positive response and demonstrates demand for this teaching resource in Australia and New Zealand but also worldwide.

Aim: To assess the introduction and use of e-learning into postgraduate radiology training in Fiji. Method: The e-learning platform Radiology Integrated Training Initiative (R-ITI) has been available to all radiology registrars in Fiji from May 2011 until present. A survey of registrars’ attitudes towards this e-learning platform as well as a usage analysis for a two-year period (from January 2012 to December 2013) was performed. Results: Between two and six registrars completed e-learning modules each month. Mean completion rate was 9.4 modules per month per registrar and each registrar had completed a mean total of 227 module. Radiology registrars in Fiji responded well to the introduction of e-learning with 100% strongly agreeing that the use of e-learning had improved their radiological knowledge and diagnostic skills. 100% of registrars either agreed or strongly agreed that they preferred e-learning to traditional resources but were either neutral or disagreed that they preferred this e-learning platform to face-to-face teaching. Barriers to implementation include protected time for completion and improved access to computers and high-speed internet. There is a strong desire from trainees for a formal training program or certification of their training. Conclusion: e-Learning has been successfully introduced as an adjunct to established teaching methods in post-graduate radiology training in Fiji. It has been positively received by trainees with sustained completion rates of modules. There is both demand and need to further develop post-graduate radiology training in Fiji.


Scientific Exhibits

259

An audit of CT head imaging in paediatric patients presenting to the Department of Emergency Department (DEM) at Nambour General Hospital (NGH) & Caloundra Hospital M Kreltszheim, C Maskiell, T Stapleton and M Kreltszheim

An audit of radiation dose of 4D CT in a radiotherapy department T Hubbard, J Callahan, J Cramb, R Budd and T Kron

Nambour General Hospital, Queensland, Australia

Aim: To review the dose delivered to patients in 4D CT used for radiotherapy treatment planning. Method: Time resolved 4D CT is used at Peter MacCallum Cancer Centre since July 2007 for radiotherapy treatment planning using a Philips Brilliance Wide More CT scanner (16 slice, helical 4D CT acquisition, all scans performed at 140 kVp and reconstructed in 10 datasets for different phases of the breathing cycle). Dose records (CT Dose Index, Dose Length Product) were analysed retrospectively for 387 patients who underwent 4D CT procedures between 2007 and 2013. Results: A total of 444 4D CT scans were acquired with the majority of them (342) being for lung cancer radiotherapy. CTDI Vol as recorded over this period was fairly constant at approximately 20 mGy for adults. The CTDI for 4DCT for radiotherapy treatment planning of lung cancers of 19.6 +/− 9.3 mGy (n = 168, mean +/− 1SD) is about 50% higher than CTDIs for conventional CT scans that were acquired in the same period with a CTDIVol 12 +/− 4 mGy (sample of n = 25). CTDI and DLP increased with increasing field of view; however, no significant difference between DLPs for different indications (breast, kidney, liver and lung) could be found. Breathing parameters such as breathing rate (range 7 to 29 breaths per minute) did not affect dose nor did the shape of the breathing pattern with helical 4D-CT. The data were also compared to 4D CT scans acquired for 4D PET (GE Discovery 690, 64 slice, Cine CT, 120 kV, fixed 10 mA). The CTDIvol in these scans that are used for attenuation correction and anatomic correlation was 6.4 +/− 2.2 mGy (n = 25). Conclusion: 4D CT scans can be acquired for radiotherapy treatment planning with a dose less than twice the one required for conventional CT scanning.

Aim: To compare indications for CT head studies in paediatric patients ( 0.05). Conclusion: MRI has been shown to be a valuable tool in the diagnosis of acoustic neuromas as confirmed by our detection rate, which exceeds those suggested in other literature (2,3). This further supports the funding of MRI as an important imaging tool for symptomatic patients. Yet debate is ongoing regarding the optimal interval for surveillance. Greater accessibility may prolong the window for conservative management and provide further information about tumour growth. MRI follow up of newly diagnosed cases is vital for selecting patients that can be stratified for serial imaging and confirming those who will not require surgery. References [1] Marx S, Langman A, Crane R. Accuracy of fast spin echo magnetic resonance imaging in the diagnosis of vestibular schwannoma. American Journal of Otolaryngology 1999 Jul-Aug; 20(4): 211–6. [2] Newton JR, Shakeel M, Flatman S, Beattie C, Ram B. Magnetic resonance imaging screening in acoustic neuroma. American Journal of Otolaryngology–Head and Neck Medicine and Surgery 2010 Jul–Aug; 31(4): 217–220. [3] Sheppard IJ, Milford CA, Anslow P. MRI in the detection of acoustic neuromas – a suggested protocol for screening. Clinical Otolaryngology 1996 Aug; 21(4): 301–4.

Children Hospital, Queensland, Australia Aim: To discuss the imaging features of various types of vascular rings in infant/children using a multi-modality imaging approach. Vascular rings and pulmonary slings are congenital malformations of the aortic arch and pulmonary vessels that encircle and cause extrinsic compression of the trachea and oesophagus resulting in respiratory and feeding difficulties in the paediatric population. Well-chosen imaging investigations with familiarity with the variations in aortic arch embryological development are important to accurately depict the abnormalities and shed insight into patient management. Method: Relevant cases were identified from our institute’s database and categorised into groups based on the Edwards classification system [1]. Six cases with differing aortic arch anomalies were selected to be included in this review. All radiological evaluations obtained from these cases including chest x-rays, oesophagrams, CT and MRI are used for discussion. Results: The following cases are discussed with reference to their corresponding imaging studies: Case 1: Double aortic arch Case 2: Right aortic arch with aberrant left subclavian artery Case 3: Left aortic arch with aberrant right subclavian artery Case 4: Right aortic arch with mirror-image branching Case 5: Pulmonary artery sling Case 6: Truncus with IAA and Aberrant LSCA Conclusion: Vascular rings are rare but important causes of persistent respiratory distress and feeding difficulties in the paediatric population. Plain chest x-rays and oesophagrams have long been used as screening tools for such congenital anomalies and to raise clinical suspicion for the diagnosis. Cross sectional imaging including CT angiography and MRI are useful to further delineate relationships between the aortic malformations and the adjacent structures and to assist in surgical planning. Reference 1. Hernanz-Schulman M. Vascular rings: a practical approach to imaging diagnosis. Paediatric Radiology 2005 July 29; 35: 961–79.


272 Stress, satisfaction and burnout amongst Australian and New Zealand radiation oncologists J Leung,1 P Rioesco1 and P Munro2 1

Adelaide Radiotherapy Centre, Adelaide, Australia, 2Royal

Scientific Exhibits Systematic review of SABR for oligometastatic breast cancer M Li, F Foroudi, S Siva, B Chua, C Phillips, T Kron and S David

Australian and New Zealand College of Radiologists,

Department of Radiation Oncology, Peter MacCallum

Sydney, Australia

Cancer Centre, Melbourne, Australia

Aim: The aims of this study were to determine the self-reported prevalence of sources of stress, job satisfaction and burnout amongst radiation oncologists in Australia and New Zealand. Methods: An anonymous online survey was distributed to all radiation oncologists listed on the Australian and New Zealand database in 2013. There were 37 Likert Scale questions on stress, 18 Likert Scale questions on job satisfaction and burnout was assessed by the Maslach Burnout Inventory – Human Services Survey (MBI-HSS). Results: There were 220 responses out of 348 eligible respondents (63.2% response rate). The most prevalent sources of stress were conflicting demands on time, too great a volume of work, interruptions, and disruption to home life. Respondents found dealing well with patients, relatives, the technical aspects of radiation oncology and being perceived by their colleagues to be doing a good job, as the most highly rated sources of job satisfaction. Three percent of respondents were high risk in all sections of burnout, whilst 14% were low risk in all sections. At least 19% were rated as high risk in one section. There were differences according to geographical location, age, sector of work and between specialist and generalist radiation oncologists. Conclusions: This first study of stress, satisfaction and burnout amongst radiation oncologists in Australia and New Zealand had a reasonable response rate and revealed specific sources and moderate levels of stress, reasonable job satisfaction and moderate levels of burnout.

Aim: This systematic review examines the evidence regarding stereotactic ablative body radiotherapy (SABR) for oligometastatic breast cancer. Method: A literature search was performed using PubMed Search for the period from February 1964 to February 2014. The search employed the following terms: “breast neoplasms”[MeSH Terms] AND (radiosurgery[Title] OR stereotactic[Title]) NOT brain[Title] NOT cerebral[Title] NOT biopsy[Title]”. Results: The search yielded a total of 109 publications of which 105 publications were not specifically related to breast cancer and SABR. Two of the remaining four studies reported the use of SABR in breast cancer and the other studies evaluated Cyberknife™ radiosurgery for spinal metastases from breast cancer. All four studies differed in radiation techniques, doses and fractionation schedules. In a phase 1 dose-escalation study of SABR delivered concomitantly with neoadjuvant chemotherapy for non-metastatic breast cancer, the highest pathologic complete response rate was achieved with a radiation dose of 25.5 Gy in 3 fractions.1 The largest study had 40 participants treated with radical intent and 11 with palliative intent.2 Eleven of the patients had prior loco-regional treatment to the disease sites. At two years of follow-up, all palliative patients died, and one patient had local disease progression. At four years of follow-up, of the patients treated radically, the overall survival was 59%, progression free survival 38% and local control 89%. In the studies that evaluated Cyberknife™ radiosurgery for spinal metastases, one study showed insignificant improvements in survival and number of complications.3 The other study reported improvement in long-term local pain, and a local control rate of 100% for previously untreated lesions.4 Conclusion: This review supports the potential of SABR as a treatment option for selected oligometastatic breast cancer patients, with local control rates approaching 100%. Prospective studies are required to investigate its toxicity and efficacy in terms of local disease control and impact on survival. References 1. Bondiau PY, Courdi A, Bahadoran P et al. Phase 1 clinical trial of stereotactic body radiation therapy concomitant with neoadjuvant chemotherapy for breast cancer. International Journal of Radiation Oncology, Biology, Physics 2013; 85(5): 1193–9. 2. Milano MT, Zhang H, Metcalfe SK, Muhs AG, Okunieff P. Oligometastatic breast cancer treated with curative-intent stereotactic body radiation therapy. Breast Cancer Research and Treatment 2009; 115(3): 601–8. 3. Gagnon GJ, Henderson FC, Gehan EA et al. Cyberknife radiosurgery for breast cancer spine metastases. Cancer 2007; 110(8): 1796–802. 4. Gerszten PC, Burton SA, Welch WC et al. Single-fraction radiosurgery for the treatment of spinal breast metastases. Cancer 2005; 104(10): 2244–54.


Scientific Exhibits Multidisciplinary and mixed modality radiotherapy solutions for complex cutaneous recurrent breast cancer – a case study S Li, P Bowden, M Enge and C Everitt 1


273 Multi detector (64+) CT angiography of the lower limb in symptomatic peripheral arterial disease – preliminary assessment of accuracy and inter-observer agreement in an Australian tertiary care setting J Lim,1 D Ranatunga,1 A Owen,1 T Spelman,3 T Mulcahy,1 J Chuen2 and R Lim1

Aim: Cutaneous dermal relapse (or metastasis) is a relatively rare phenomenon, with an overall occurrence rate of up to 10% (1) for patients with noncutaneous primary cancer, and can have variable clinical appearances. This case study presents with widely metastatic invasive ductal carcinoma of the breast (status postpalliative bilateral mastectomy and axillary clearance), describing the challenging and complex planning and treatment approaches adopted to achieve local control of their extensive dermal disease. Method: A 69 year old lady, who has had double mastectomy, with adjuvant chemo-radiotherapy in 2008, presented with history of severe and progressive cutaneous breast cancer recurrence involving bilateral anterior chest wall area overlapping and proximal to previous treatment areas, with new disease involving the back, left shoulder, left arm and upper abdominal area and referred for external beam radiotherapy. Results: Over 8 months, each symptomatic area was treated, separated into three consecutive courses, which included (i) left and right anterior chest wall (ii) posterior chest wall and (iii) anterior and lateral left flank and left shoulder and arm. A combination of conformal photon, Intensity Modulated RT and electron junctional fields was used to best suit the patient contour across the torso and upper limb dermal relapse region. A treatment regime of 60 Gy in 40 fractions using twice daily fractionation and concurrent Carboplatin and Taxol was prescribed for all courses. Previous treatment areas and volumes were assessed to ensure minimum overlap. The patient had an excellent clinical response to radiotherapy for her subcutaneous breast cancer with her skin healing well and most lesions completely resolving besides a few asymptomatic nodules outside her radiotherapy fields. Conclusion: This patient’s clinical course illustrates how mixed modality pathway of localised radiotherapy in conjunction with chemotherapy can be particularly effective in controlling severe progressive metastatic breast cancer. Reference 1. Lehman JS, Benacci JC. Cutaneous metastasis of invasive ductal carcinoma of the breast to an infusaport site. Cutis 2008; 81: 223–6.

1

Austin Health – Radiology, 2Austin Health – Vascular

Surgery, 3Burnet Institute, Victoria, Australia Aim: To evaluate accuracy and inter-observer agreement of current generation (64+ detector) multi-detector CT angiography (MDCTA) for detection of haemodynamically significant stenosis in patients with symptomatic peripheral arterial disease (PAD) in an Australian tertiary care hospital using digital subtraction angiography (DSA) as the reference standard. Method: A retrospective cross-sectional study was performed in a preliminary group of 10 patients (mean 64 yrs, 8 male) with symptomatic PAD (5 claudicants, 3 rest pain, 1 tissue loss, 1 acutely ischaemic) who underwent lower limb MDCTA (64- or 80-detector) and DSA. Arterial stenosis was independently graded as not significant (38). PETRA images produced more artefacts especially below 50 μs.

Fig. 1. (left to right) 0.8 mm UTE images with TE = 40 μs, 4.9 ms and the subtraction. Note signal from the normally MR-invisible cushion.

References 1. Biko D, Anupindi S. Childhood Burkitt lymphoma: abdominal and pelvic imagings. AJR 2009; 192(5): 1304–15. 2. Sandlund JT, Downing JR. Non-Hodgkin’s lymphoma in childhood. N Engl J Med 1996; 334: 1238–48. 3. Dunnick NR, Reaman GH. Radiographic manifestations of Burkitt’s lymphoma in American patients. AJR 1979; 132: 1–6.

Conclusion: Initial results demonstrate the feasibility of using ultrashort TEs to visualise cortical bone. This has potential application in radiotherapy planning and further in vivo studies are planned.


Scientific Exhibits A tertiary hospital audit of the use of medical imaging in the 24 hours preceding death D Liu, J Weil, M Boughey and T Sutherland St Vincent’s Hospital, Melbourne, Australia Aim: Radiology is easily accessible and used frequently in hospitals all around the world. Sometimes clinicians do not properly consider whether patients actually need investigations such as imaging. This study aims to investigate the number, modality and reason of imaging studies performed for patients within the 24 hour window prior to their death. Method: Retrospective analysis of 1855 deceased patients from a tertiary hospital (St. Vincent’s Hospital, Melbourne) within a two year period (0/1/11/2011 to 01/11/2013). Information obtained from medical records online (MRO) and picture archiving and communication systems (PACS). Patients categorised into emergency department patients, inpatients (non-intensive care unit) and intensive care unit (ICU) inpatients. Imaging modality and reason for imaging also recorded. Results: 1855 patients died between 01/11/2011 to 01/11/2013 at St. Vincent’s Hospital, Melbourne. 378 patients received imaging within the last 24 hour window prior to their death of which 364 were inpatients (187 ICU patients and 167 non ICU patients) and 14 emergency department (ED) patients. 458 xrays, 97 computer tomography (CT), 36 ultrasound scans (USS), 2 magnetic resonance imaging (MRI), 5 nuclear medicine (NM) and 3 interventional radiology (IR) were performed in total. Reasons for imaging were 69 scans for tube/line position confirmation, 378 scans for investigation of symptoms/pathology, 118 scans for monitoring of disease and 36 other including unstated reason for imaging, IR or post mortem examination for organ donation. Conclusion: Medical imaging carries with it certain discomfort and morbidity that can be avoided if clinicians think carefully about the overall clinical picture and viable treatment plans prior to requesting imaging. Also, ICU patients may not require as many regular daily chest xrays as currently performed with little overall effect on patient management potentially having a negative impact on patient morbidity.

275 Epidermal growth factor receptor (EGFR) mutation analysis in advanced non-small cell lung cancer (NSCLC): impact on radiotherapy practices at a regional tertiary institution H Liu,1 A Joshi2 and A Tan1 1

Department of Radiation Oncology – Townsville Cancer

Centre, 2Department of Medical Oncology – Townsville Cancer Centre, Queensland, Australia Aim: In patients with advanced NSCLC that are EGFR mutation positive, EGFR tyrosine kinase inhibitor (TKI) therapy has improved progression free survival (PFS) compared to chemotherapy.1–3 Palliative radiotherapy is utilised for symptom control in these patients. We examined the impact of EGFR mutation analysis on radiotherapy practices at our regional tertiary institution. Method: Between June 2011 and June 2013, 55 consecutive patients diagnosed with advanced NSCLC (stage IIIB and IV) who had EGFR mutation analysis performed on biopsy specimens were retrospectively evaluated. Comparisons were made between EGFR mutation positive and negative patients on the number receiving palliative radiotherapy, time from diagnosis to first radiation treatment and number of sites treated with radiotherapy. One sided statistical analyses were performed utilising Fisher’s Exact Test and Independent-Samples T-test. Results: EGFR mutation was detected in eight patients and not detected in 47. Four of eight (50%) patients with the EGFR mutation received radiotherapy and 26/47 (55%) patients without EGFR mutation underwent radiotherapy (p-value = 0.54). For patients that had radiotherapy, mean time to first radiation treatment was 209 days in the EGFR mutation positive group and 99 days in the negative group (p-value = 0.11). Mean number of sites treated with radiotherapy was 1.25 in the mutation positive group and 2.04 in the mutation negative group (p-value = 0.03). Sites of radiation treatment were illustrated in Figure 1.

40%

EGFR mutation +ve

30%

EGFR mutation -ve

20%

Appendicular skeleton

Brain

0%

Spine

10% Chest

Proportion to total sites treated

50%

Treatment sites

Fig. 1. Sites of radiation therapy.

Conclusion: EGFR mutation positive patients with advanced NSCLC appear to have fewer sites treated with radiotherapy than EGFR mutation negative patients. There was no significant impact of EGFR mutation analysis on proportion of patients receiving radiotherapy and time to first radiotherapy course. Despite improvements in PFS with EGFR TKI therapy, these findings suggest there is ongoing need for palliative radiotherapy for symptom control in advanced NSCLC patients.


276

References 1. Lee CK, Brown C, Gralla RJ et al. Impact of EGFR inhibitor in non-small cell lung cancer on progression-free and overall survival: a meta-analysis. J Natl Cancer Inst 2013 May 1; 105(9): 595–605. 2. Fukuoka M, Wu Y-L, Thongprasert S et al. Biomarker analyses and final overall survival results from a phase III, randomized, openlabel, first-line study of gefitinib versus carboplatin/paclitaxel in clinically selected patients with advanced non-small-cell lung cancer in Asia (IPASS). J Clin Oncol 2011 Jul 20; 29(21): 2866–74. 3. Rosell R, Carcereny E, Gervais R et al. Erlotinib versus standard chemotherapy as first-line treatment for European patients with advanced EGFR mutation-positive non-small-cell lung cancer (EURTAC): a multicentre, open-label, randomised phase 3 trial. Lancet Oncol 2012 Mar; 13(3): 239–46.

Scientific Exhibits Shielding effects of the primary collimator: Assessment of the accuracy of treatment planning system dose calculations out-of-field P Lonski,1,2 R Franich,2 M Taylor,2,3 W Hackworth1 and T Kron1,2 1

Physical Sciences, Peter MacCallum Cancer Centre,

2

School of Applied Sciences, RMIT University, Melbourne,

Australia, 3Technical and Forensic Intelligence, Australian Federal Police, Victoria, Australia Aim: To assess the effect of primary collimator shielding for out of field dosimetry and the ability of a commercial treatment planning system to predict this. Method: The primary collimator of a linear accelerator provides shielding beyond the maximum useful treatment field which is not explicitly modelled in most treatment planning systems. High-sensitivity thermoluminescence dosimeter (LiF:Mg, Cu P TLD) chips were placed at 2.0 cm depth with 7.0 cm backscatter in a 1.5 m long stack of solid water slabs at increasing distance from the beam central axis on a Varian 21iX linear accelerator. Scatter material (solid water) was provided in the primary beam. Measurements were conducted for various field sizes. TLD data were compared to calculations in the Eclipse (Varian Medical Systems) treatment planning system using Pencil Beam Convolution (PBC), Anisotropic Analytical Algorithm (AAA) and Acuros XB (XB). Results: Dose profiles were measured out-of-field at 1 cm intervals using TLD chips. Results are shown in the figure. A sharp decrease in dose occurs between 22 and 25 cm for the 3 × 3 cm2 field which is not modelled by any of the dose calculation algorithms in the planning system. This effect was not detectable at larger field sizes (ie 30 × 30 cm2) due to the relative dominance of phantom scatter from the primary beam, although can still be seen in the case of a 10 × 10 cm2 field. Conclusion: Leakage dose is not explicitly modelled by treatment planning systems. Corrections for leakage dose may require an additional component within regions affected by shielding from the primary collimator, particularly for smaller fields.


Scientific Exhibits Pre-treatment verification in HDR brachytherapy at the Chris O’Brien Lifehouse: Radiation therapy experience A Lovett,1 M Whitaker,1 G Hruby,1,2 J Toohey1 and N Patanjali 1

1

277 Hip hip but no hooray: Paediatric ultrasound in hip pain T Nguyen,1 L Lukic2 and A Taranath2 1

Flinders Medical Center, Adelaide, Australia, 2Womens and

Childrens Hospital, Adelaide, South Australia, Australia

Chris O’Brien Lifehouse, 2University of Sydney, Sydney,

New South Wales, Australia Aim: To update the pre-treatment verification procedures in use for HDR Brachytherapy at the Chris O’Brien Lifehouse. Method: Following the introduction of new staff members into the multidisciplinary brachytherapy team, critical points in the treatment process were identified at which additional checking would reduce the possibility of error. The brachytherapy advisory group assessed and evaluated these points during the HDR brachytherapy procedures at which errors could occur. Assessment was undertaken in a multidisciplinary environment with the various staff groups involved (Radiation Therapists, Physicists, Radiation Oncologists and Radiation Oncology Nurses) taking responsibility for the particular quality aspects most relevant to their specialty. Identified radiation therapist responsibilities (in addition to existing correct patient, correct site, correct procedure checks and treatment plan checks) include formalising the checking procedure for confirmation of applicator size, transfer tube connection, pre-treatment imaging, pre-treatment imaging review and use of ancillary equipment. Results: Following the assessment of brachytherapy processes, existing protocols and procedures were expanded and enhanced to address the identified weaknesses. As brachytherapy treatment of different sites (gynaecological vs genito-urinary vs gastro-intestinal) requires differing equipment and staff, specific changes were made to the procedural documentation for each of the sites treated at this facility. A brachytherapy specific timeout protocol was also developed in order to formalise generic brachytherapy pre-treatment requirements. Conclusion: Comprehensive pre-treatment verification is essential for the quality and safety of any patient procedure treatment. Pretreatment verification processes and procedures have been updated and implemented for all sites treated with brachytherapy at the Chris O’Brien Lifehouse.

Background: Paediatric hip pain and limp are common presentations to the emergency department and the family practitioner. Ultrasonography is an ideal modality in assessing these patients, particularly given the lack of ionising radiation (1, 2). Sonography can readily detect a joint effusion which can be seen in the setting of transient synovitis, septic arthritis and less commonly, haemarthrosis (1). Hip pain however can be a non-specific or referred symptom and may arise from pathology related to: • Intra- and extra-articular osseous structures (pelvic osteomyelitis, pelvic avulsion fractures, toddler fractures, slipped capital femoral epiphyses) • Peri-articular soft tissues (myositis, intramuscular abscess, neoplastic lesions) • Intra-abdominal viscera (acute appendicitis, Crohn’s disease) • Retroperitoneal structures (psoas abscess, neuroblastoma, vertebral osteomyelitis/discitis) (1–3) At our institution, if no primary hip pathology is found we routinely extend the ultrasound examination. In our experience the ultrasound examination is highly capable of identifying conditions masquerading as hip joint pain and directing further focussed investigations, thereby avoiding a delay in diagnoses. Aim/Method: We present a pictorial review of various pathologies diagnosed on ultrasound in paediatric patients presenting to our institution with hip pain or limp. Through this visual kaleidoscope, we aim to reinforce less common but important differential diagnoses that need consideration in the evaluation of a child with hip pain. Conclusion: Ultrasound is a useful imaging modality in the imaging the child with hip pain. A high index of suspicion is required to detect extra-articular pathologies which may be the cause of the presentation. References 1. Crow A, Cheung A, Lam A, Ho E. Sonography for the investigation of a child with a limp. Australian Journal of Ultrasound Medicine 2010; 13(3): 23–30. 2. Sawyer J, Kapoor M. The limping child: a systematic approach to diagnosis. American Family Physician 2009; 79(3): 215–24. 3. Harcke H, Grissom L. Pediatric hip sonography: diagnosis and differential diagnosis. Radiologic Clinics of North America 1999; 37(4): 787–96.


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Scientific Exhibits

Benefits of delivering an instrumentation course online: Student perspective J MacDonald-Hill and H Warren-Forward

Factors influencing radiology specialty choice amongst junior doctors N Maggacis,1 A Pearce2 and D McMenamin3

University of Newcastle, New South Wales, Australia

1

Princess Alexandra Hospital, Brisbane, Queensland,

Australia, 2Queen Elizabeth Hospital, South Australia, Aim: In 2013, a previously face-face formatted instrumentation course was taught fully online. A study was conducted to assess the thoughts and experiences of the students who completed the course and to identify ways to improve the educational experience based on their feedback. Method: An anonymous online survey was distributed to all 86 students who completed the course. It consisted of questions relating to their engagement with the teaching materials and learning resources made available as well as gathering ideas and direction for future course developments. A comparative results analysis was also conducted, assessing both the 2013 and 2012 results to assess if there were any differences in outcomes between teaching formats. Results: The survey was completed by 36 (42%) students. The comparative results analysis showed that there was no significant difference (p = 0.74) between the median results of students who completed the face-face format (73%) to the online format (73%). As most of the students (83%) undertake paid employment, it was not surprising that they preferred new learning content such as lectures to be delivered online (71%) but still had preference for face-face tutorials (85%). Participants indicated that they thought that the use of integrated quizzes (94%) and activities (88%) and the use of multiple images (63%) would be most and very useful to their learning. Conclusion: With consideration to both students’ perception and comparative results analysis, it is indicated that a positive outcome was achieved and future development and implementation of this concept is well justified.

Australia, 3Noosa Radiology, Queensland, Australia Aim: To identify factors that influence radiology as a specialty choice amongst junior doctors. Method: A survey-based questionnaire was administered to 58 junior doctors at a radiology education seminar. The data obtained included demographic details, factors favourably influencing choice of specialisation in radiology and reasons for non-consideration of radiology. Data were analysed using descriptive and statistical analysis. Results: Forty-nine percent (49%) of respondents were male and fifty-one percent (51%) were female. The majority of survey participants (69%) were in their second postgraduate year. Factors positively associated with selecting a career in radiology included: lifestyle (50%), lack of patient contact (23%), attitudes of radiologist in their workplace (12%) and technical advancements (9%). Only 5% of respondents reported an interest in radiology from a diagnostic point of view. The main reasons for non-consideration of radiology included: lack of patient contact (58%), attitudes of radiologists in the workplace (40%) and lifestyle (4%). Conclusion: Lack of patient contact, attitudes of radiologists in the workplace and lifestyle were significant factors favourably influencing junior doctors’ career choice in radiology. Comparatively, diagnostic decision making had minimal influence on radiology specialty choice. Attitudes of radiologists were also, surprisingly, a significant factor deterring junior doctors from a career in radiology. An understanding of the determinants influencing junior doctors’ selection of radiology specialisation may assist educators to attract and maintain interest in radiology as a career.


Scientific Exhibits A quality audit and clinical correlation of CTPAs on a 64 Slice CT scanner in a regional teaching hospital in Australia G Mander and N Tosh Queensland Health, Queensland, Australia

279 A comparison of radial and femoral arterial access with radiation dose in percutaneous coronary procedures M Mansfield,1 D Brieger2 and W Abhayaratna3 1

Australian National University, Australian Capital Territory,

Australia, 2Concord General Repatriation Hospital, University of Sydney, New South Wales, Australia, 3The Canberra

Introduction: A quality audit of current practice in performing CT scans of the pulmonary arteries (CTPA) was conducted at Toowoomba Hospital (TH). Successful CTPAs have been defined in the literature by having a contrast enhanced Hounsfield Unit (HU) of 200 or over in the pulmonary trunk (PT). Aim: This study investigated the success or rate of CTPAs at TH. A follow up investigation provided correlation with the HU and the radiologist’s reports. Methods: The HU for all CTPAs performed at TH over the previous year were measured in four regions – the superior vena cava, the pulmonary trunk and venous return in the pulmonary veins. These data were correlated with radiology reports of the scans. Results: Of the investigated CTPAs 19% did not have HUs over 200 in the measured regions indicating sub-optimal imaging. The scans that had sub-optimal imaging were largely described in the radiologists report as sub-optimal. Discussion: The number of CTPAs with sub-optimal contrast enhancement in the PT was high. 1 in 5 scans audited was considered to be a ‘failed’ scan. These findings were corroborated with the radiologist’s clinical description of sub-optimal in the report. Conclusion: A high number of failed CTPA scans suggest that CTPA imaging needs to be improved. Results from this study are suggestive that breath holding, timing of contrast bolus and cannula placement are areas that could be investigated further to understand the reasons behind the high failure rate of CTPA investigations.

Hospital, Australian National University, Australian Capital Territory, Australia Aim: To determine if radial artery access is associated with a difference in ionising radiation dose compared to femoral artery access when performing diagnostic coronary angiography in a tertiary referral catheter laboratory in Australia. Method: This study was a clinical audit of a tertiary referral hospital cardiac catheterisation laboratory specifically of patients undergoing diagnostic coronary angiograms. Data were collected on patient demographics (age, gender) and procedural aspects (screening time, radiation dose, angiographic runs and arterial approach). Patients were grouped by arterial access (radial or femoral access) and technical factors were compared. Results: Radiation dose was significantly higher for the radial arterial access group as measured by air kerma (953 +/− 696 vs. 828 +/− 531, p = 0.011) with age having no significant effect. After multivariable analysis adjusting for age and gender the difference in radiation dose between the groups was still statistically significant. Conclusion: Radiation dose received by patients for coronary procedures performed by the radial route are higher when compared to the same procedures performed by the femoral route. This study was limited by the lack of information available on body habitus and operator experience and further studies are required to address the effect of these confounders.


280 NSAID-associated enteropathy (“diaphragm disease”): Presentation of four cases and review of clinical/imaging spectrum J Freebody,1 K Marripudi,1 A Kheir,2 D Markan,1 J Fiatarone,2 G Hawken,2 M Veysey,2 S Singh,2 D Gilbert2 and J Hanson1 1

Medical Imaging Department, Gosford Hospital,

2

Gastroenterology Department, Gosford Hospital, New South

Wales, Australia

Scientific Exhibits

3. Levi S, de Lacey G, Price AB, Gumpel MJ. Levi AJ, Bjarnason I. “Diaphragm-like” strictures of the small bowel in patients with nonsteroidal anti-inflammatory drugs. British Journal of Radiology 1990; 63: 186–9. 4. Zalev AH, Gardiner GW, Warren RE. NSAID injury to the small intestine. Abdominal Imaging 1998; 23: 40–44. 5. Flicek KT, Hara AK, de Petris G, Pasha SF, Yadav AD, Johnson CD. Diaphragm disease of the small bowel: a retrospective review of CT findings. American Journal of Radiology 2014; 202: W140–5.

Aim: Non-steroidal anti-inflammatory drug (NSAID)-associated enteropathy (“diaphragm disease”) is characterised by excessive NSAID intake, small bowel inflammation/ulceration, and short (“diaphragmlike”) strictures.1,2 There are few reports describing the imaging findings.3–5 The condition may mimic other small bowel disorders. We aim to describe four patients with NSAID-associated enteropathy and to review the disease spectrum. Method: Patient 1: 30-year-old female (background chronic back pain and heavy NSAID consumption) represented three days following endoscopic dilatation of stenosed pylorus with abdominal pain and vomiting. Patient 2: 62-year-old female (background long-term NSAID use and suspected Crohn’s disease) presented with exacerbation of abdominal pain and obstructive symptoms. Patient 3: 32-year-old male (background recurrent pancreatitis/ excessive NSAID use) presented with acute abdominal pain, vomiting and anaemia. Patient 4: 38-year-old female (chronic back pain, depression, endometriosis and excessive NSAID intake) presented with weight loss, anaemia and lower abdominal pain. Results: Patient 1: CT showed distal small bowel obstruction without cause. Ileal resection showed three stenosed lesions and histologic features of NSAID-associated diaphragm disease. After prolonged postoperative course, intestinal symptoms improved. Patient 2: CT showed narrowing/thickening of 25–30 cm terminal ileum, prominent fat-wrapping and upstream dilatation. Ileo-caecal resection showed diaphragm disease. There was slow resolution of abdominal symptoms. Patient 3: CT showed several dilated mid small bowel segments and intervening short narrowings. He required laparotomy, stricturoplasty (4 strictures) and resection (3 clustered strictures). Histopathology showed moderate serositis. Anaemia and obstructive symptoms resolved following surgery and NSAID cessation. Patient 4: Ultrasound and CT showed several dilated mid small bowel segments with intervening thick-walled strictures, and minor mesenteric lymphadenopathy. Anaemia improved with cessation of NSAID intake, but intermittent obstructive symptoms progressed. Conclusion: NSAID-associated enteropathy (“diaphragm-disease”) should be considered in the differential diagnosis of small bowel thickening/strictures, particularly subacute obstructive presentations in patients with excessive NSAID intake. References 1. Lang J, Price AB, Levi AJ, Burke M, Gumpel JM, Bjarnason I. Diaphragm disease: pathology of disease of the small intestine induced by non-steroidal anti-inflammatory drugs. Journal of Clinical Pathology 1988; 41: 516–26. 2. Slesser AA, Wharton R, Smith GV, Buchanan GN. Systematic review of small bowel diaphragm disease requiring surgery. Colorectal Disease 2012; 14: 804–13.


Scientific Exhibits Hemiplegic migraine: Presentation of two cases and review of clinical and imaging findings K Marripudi,1 J Freebody,1 J Evans,2 R Lee,1 D Crimmins,2 E Reyneke2 and J Hanson1 1

Medical Imaging Department, Gosford Hospital, 2Neurology

Department, Gosford Hospital, New South Wales, Australia Aim: To describe the clinical and radiologic features in two patients with hemiplegic migraine (combination of migraine-type headache with aura and short-term neurological signs). To review the spectrum of imaging findings and relevant differentials. Method: Patient 1: 24-year-old female with long history of common migraine presented with two-day history of occipital headache, left sided hemiplegia and paraesthesia, dysarthria and confusion. Laboratory tests (including LP) were unremarkable. She was initially treated with acyclovir and prednisone, subsequently with antiepileptics and supportive measures. Symptoms completely resolved over 2–3 weeks. Patient 2: 75-year-old female, with history of similar previous episodes, presented with headache, right sided weakness, dysphasia, and seizure. She was treated with continuing anti-epileptic medication and supportive measures. Symptoms gradually resolved over 4 weeks, with no residual deficit. Results: Patient 1: Non contrast CT brain was normal. MRI (day 5) showed cortical swelling and increased signal throughout the right hemisphere on T2/FLAIR sequences. Diffusion-weighted imaging showed minor cortical hyperintensity without restricted diffusion. TOF MRA showed normal intracranial arteries. There was mild increased vascularity on post iv gadolinium T1 sequences. Repeat MRI (day 14) showed progressive right hemisphere swelling, left sided shift of midline structures and uncal herniation. Repeat MRI (6 weeks) showed subtle residual cortical signal abnormalities, and no infarction. Patient 2: Non contrast CT brain was normal. Repeat CT (day 7) showed left cerebral swelling. MRI (day 10) showed cortical swelling and increased signal involving most of the left hemisphere on T2/FLAIR sequences. There was minor cortical hyperintensity on diffusion-weighted imaging, without restricted diffusion. The spectrum of clinical and imaging findings in hemiplegic migraine will be presented. Conclusion: Diagnosis of hemiplegic migraine is based on clinical features. The role imaging is to rule out conditions which may mimic the diagnosis, and to distinguish between persistent aura and migrainous infarction.

281 Outcomes of definitive intensity modulated radiotherapy with simultaneous boost for oropharyngeal squamous cell carcinoma in a regional Australian cancer centre from 2010 to 2014 R Masoud Rahbari,1 L Winkley,1,4 J Hill,1,4 R Tahir,1,3 T Shakespeare1,3 and P Dwyer1,2 1

North Coast Cancer Institute, Queensland, Australia,

2

Lismore Base Hospital, New South Wales, Australia, 3Coffs

Harbour Hospital, New South Wales, Australia, 4Port Macquarie Hospital, New South Wales, Australia Introduction: The incidence of oropharyngeal SCC has increased over the last 2 decades, largely because of an increase in HPV associated oropharyngeal cancer. We aim to report the outcomes of definitive treatment for mucosal oropharyngeal SCC with IMRT and simultaneous integrated boost in a regional Australian cancer centre. The North Coast Cancer Institute (NCCI) includes 3 sites with established and consistent process for vigorous QA checks prior to IMRT treatments based on NCCI and Cancer Institute NSW (eviQ) protocols. Patients have access to allied health support during all stages of their treatment and follow up. Methods: We retrospectively reviewed electronic medical records of all patients treated with IMRT for head and neck cancer. Those patients who were treated with curative intent definitive IMRT for oropharyngeal cancer were included. 48 patients were eligible for analysis based on the inclusion criteria. We then analysed patient, tumour and treatment characteristics and tumour control outcomes and toxicities. Results: From 48 patients, 83% were male and median age was 57 years. 44 patients (92%) were stage III/IV and received concurrent systemic therapy. 4 patients (8%) were stage I/II and received single modality radiotherapy. 66% (32 patients) were p16 positive. The median radiotherapy dose received was 70 Gy in 35 fractions (range, 63.9–70 Gy). At a median follow-up of 10 months (range, 1–40 months), the loco-regional control rate was 96% and overall survival was 90%. No grade 4 toxicity recorded. Recorded acute grade3 toxicities were dysphagia (30%) followed by mucositis (16%), pain (12%), xerostomia (6%), dysgeusia (4%), dermatitis (4%), nausea and fatigue (2%). Only 3 patients recorded as having grade3 late toxicity in the form of dysphagia. Conclusion: We believe that our results of treating oropharyngeal SCC patients with definitive IMRT according to departmental and eviQ guidelines are very encouraging. We acknowledge the need for longer term follow up in relation to treatment outcomes and toxicity.


282 ProSPER-82: A prospective phase II trial investigating SpaceOAR® hydrogel in patients with prostate cancer receiving dose escalated radiotherapy to 82Gy trial – a radiotherapy planning perspective of clinical implementation B Mastroianni

Scientific Exhibits Effectiveness of gonad shields: A Monte Carlo evaluation Y Matyagin,1 P Collins,1 S Ruwoldt,2 S Chew2 and J West2 1

Department of Nuclear Medicine, Royal Adelaide Hospital,

2

Radiology Department, Royal Adelaide Hospital, South

Australia, Australia

Epworth Radiation Oncology, Victoria, Australia Aim: This paper will describe initial planning experiences with implementing the ProSPER-82 trial for patients undergoing radical radiotherapy for clinically localised prostate cancer. Method: The trial involves the insertion of SpaceOAR® hydrogel into the retro prostatic space to introduce a physical gap between the prostate and rectum, in theory allowing for dose escalation to the prostate, without increasing rectal side effects. The trial aims to primarily assess treatment toxicity, quality of life and survival endpoints. The trial introduced new challenges and changes to work processes for the radiotherapy planning team. These include modification of standard Intensity Modulated Radiotherapy (IMRT) dose constraints and plan acceptability guidelines along with calculating the Normal Tissue Complication Probabilities comparing dose escalated and nondose escalated IMRT plans. Results: From a dosimetric perspective, significant decrease in rectal wall doses were observed in the majority of the first 10 cases. It was however more difficult to meet dose constraints in specific circumstances attributed to patient characteristics and SpaceOAR® hydrogel placement. Conclusion: Our experience with the ProSPER-82 study to date has demonstrated promising results in the move towards dose escalation, without increasing dose to the rectal wall.

Aim: Gonad shields are often used on patients during chest X-ray procedures. Their use complicates, and possibly compromises, the procedure while their role in reducing patient dose is controversial. In this analysis Monte Carlo radiation transport code (EGSnrc) was used to simulate a gonad shield (0.5 mm lead) used for a chest X-ray. Method: The “patient” phantom was a tissue equivalent 80(×) 34(y) 24(z) cm rectangular parallelepiped in air. The following parameters for a typical chest X-ray were simulated: tube voltage = 100 kV, Dose Area Product = 70 mGy·cm2, source to skin distance = 152 cm, source to image distance = 180 cm, X-ray image field size = 43 × 35 cm. Depth dose (z) measurements were made in 2(×) 32(y) 2(z) cm voxels in the phantom (behind the “shield”) and expressed as dose difference (μGy) from the unshielded values. Separate simulations with dose estimates in 0.002 cm deep voxels evaluated the effect of dose build-up from electrons ejected from the lead on the “patient” side. (A thin plastic film (0.2 mm) simulated the cover.) Results: The effectiveness of the shield at varying depths and distances from the edge of the X-ray beam is illustrated below. X-ray/ electron radiation scattered from the lead caused a small dose increase in top 0.2 cm layer of voxels only – and less than 9 cm from edge of X-ray field. Dose build-up from ejected electrons did not extend more than 0.006 cm beyond the lead (removed by plastic). Conclusion: (i) Abdominal shields provide negligible dose reduction to organs at depth. (ii) Radiation scattered from gonad shields results in a small (but negligible) increase in skin dose.


Scientific Exhibits Hyperacute ischaemic changes on non-contrast CT brain B McAllister and L Lam Liverpool Hospital, New South Wales, Australia

283 From traumatic haemothorax to empyema: The thick and thin of it M McGuiness, M Handy and P Cleland Royal Brisbane and Women’s Hospital, Queensland,

Aim: Current literature defines the early signs of acute ischaemia on non-contrast CT brain to include the following findings: (i) hypoattenuating brain tissue; (ii) obscuration of lentiform nucleus; (iii) dense MCA sign; (iv) “insular ribbon sign”; (v) sulcal effacement 1,2. Proposed limitations with findings ii, iii and iv is that they define specific anatomic regions. The aim of this case review was to assess for any further subtle changes in the hyperacute stage of infarction that indicate cerebral ischaemia which may subsequently lead to earlier intervention or further diagnostic imaging. Methods: Retrospective review of non contrast CT brains in cases of confirmed acute stroke at Liverpool Hospital over a 12 month period. Cases with excessive motion artefact and obvious acute ischaemic changes were excluded. Initial CT brain with no definable features of ischaemia was reviewed to assess for a possible hyperacute sign of infarction. Results: A feature of hyperacute infarction not previously described was identified. In some cases this feature was evident before the more acute findings of sulcal effacement and hypoattenuation of the brain tissue. The feature is loss of distinctness, or blurring, of the cortical surface. Conclusion: Hyperacute ischaemia may be detected on non-contrast CT brain by the loss of distinctness of the cortical surface. References 1. R von Kummer et al. Acute stroke: usefulness of early CT findings before thrombolytic threapy. Radiology 1997; 205: 327–33. 2. N Tomura et al. Early CT findings in cerebral infarction: obscuration of the lentiform nucleus. Radiology 1988; 168: 463–7.

Australia Aim: Haemothorax is a common finding in trauma patients, with up to 10% of patients requiring surgical management for retained haemothorax or empyema. The project aim is to review the imaging finding to help determine if imaging can aid in detection of complications and selecting patients who will benefit from conservative treatment without tube thoracotomy. Method: All trauma patients presenting to the Royal Brisbane and Women’s hospital in a two year period with the imaging finding of haemothorax were included. Data collected included: patient demographics, CT findings (including size and density of the haemothorax, and presence of rib fractures, pneumothorax, contusions and extra thoracic injuries), management, follow up imaging and subsequent complications (retained haemothorax and empyema in particular). Results: Of the 95 patient presenting with traumatic haemothorax, all except three were diagnosed on CT. Associated thoracic injuries included pneumothorax (50%), pulmonary contusion/laceration (60%) and rib fractures (86%). Of the patients without rib fractures over half had diaphragmatic rupture or aortic injury. Complications included retained haemothorax (5%), empyema (3%) and iatrogenic liver laceration (1%). Nine patients proceeded to video-assisted thorascopic surgery (VATS). Loculated effusion was a common finding in all patients with either retained haemothorax or empyema. Of the 35 patients treated conservatively, only three required subsequent thoracostomy. Conclusion: Detection of a loculated effusion in a patient with traumatic haemothorax is a strong predictor for requiring further intervention for either retained haemothorax or empyema, presence of residual effusion was not.


284

Scientific Exhibits

Radiologic-pathologic correlation of intracranial neoplasms with standard MRI sequences – A pilot study H McKay and P Brotchie

Integrating C-arm CT: Are more arms really that helpful? R Arumugasamy, L Ricardo, F Margery, S Perring,

St. Vincent’s Hospital – Department of Medical Imaging,

University of Newcastle, New South Wales, Australia

A Stonham and S McKiernan

Victoria, Australia Aim: The primary aim was to assess the sensitivity and specificity of cranial MRI in the diagnosis of intracranial neoplasms by assessing the correlation between imaging and tissue diagnosis. This allowed the identification of mismatches which can be used to elucidate any systematic diagnostic errors, the reason for these, and what may be done to improve diagnostic accuracy. Method: Retrospective single centre audit devised of patients sourced primarily via the pathological specimen coding for neurologic tissue biopsies. WHO diagnostic criteria defined the study parameters which included all intracranial primary or metastatic malignant neoplasms (1). The population data included all adult patients from 2012 that had both cranial MRI imaging and histopathology performed at St. Vincent’s Melbourne Public or Private Hospitals. This totalled 114 unique and previously uncharacterised intracranial neoplasms. Analysis of the corresponding patient MRI report was compared with that obtained histologically. Results: The results demonstrate a high level of accuracy from diagnostic MRI in the gross diagnosis and grading of previously uncharacterised intracranial neoplasms at our tertiary institution. Discordance between histological diagnosis and the radiological diagnosis was identified in less than 10% of cases overall. There was however a relative lack of further subtyping of intracranial neoplasms ventured radiologically, and where a more specific diagnosis was reported this often did not correspond with the histological typing. Conclusion: Discrepancies primarily occurred with less common tumour entities or with atypical presentations of more common tumours. This pilot study allowed our tertiary institution to review our sensitivity and specificity in the diagnosis of intracranial neoplasms. The long term aim is to consider ongoing quality assurance projects to further refine radiodiagnosis, allow ongoing education, and ultimately help to discern prospectively the imaging characteristics that will enable better diagnostic accuracy.

Aim: This technology is a new and stimulating area of investigation within radiology and the aim of this poster is to investigate the C-arm cone beam CT systems common uses in both theatre and interventional radiology and gain knowledge on its function and features. Method: The literature has been explored in terms of C-arm cone beam CT within radiology along with a comprehensive assessment of both the limitations and benefits of its use. The advantages of this technology will be compared with other imaging modalities such as conventional CT and fluoroscopy in terms of image quality, dose, costs and use within procedures. Results: C-arm cone beam CT is a hybrid imaging CT system which has been developed for the purpose of acquiring CT images within surgical and interventional procedures. Overall, C-arm cone beam CT is unique in its design and operation. Its unique advantages include: significant manoeuvrability and mobility, ease of operation and processing, production of precise images and 3D reconstructions within the operating suite, high diagnostic image quality and a comparable reduction of dose from conventional CT. It possesses many potential uses within medical procedures, particularly lending itself to neurovascular, cardiac, spinal, visceral, and oncological procedures. Conclusion: C-arm cone-beam CT is a fascinating new technology for the field of radiology and provides many benefits for both surgical and interventional procedures. The use of this technology has so far proven to increase certain procedural success and patient outcome.

Reference 1. International Classification of Diseases (ICD). World Health Organisation (WHO); 1994.


Scientific Exhibits Radiography abroad: A firsthand experience of Nepalese healthcare J Mahon and S McKiernan

285 X-rays as art S McKiernan and A Bottaro University of Newcastle, New South Wales, Australia

University of Newcastle, New South Wales, Australia Aim: Having volunteered in university holidays, as part of a student medical team, I experienced healthcare in Nepal first hand and gained a different perspective on radiology practices. This poster explores my journey. Method: As part of the volunteering organisation Antipodeans Abroad, I spent five weeks in Pokhara, Nepal gaining clinical experience in Manipal hospital and its outreach clinics. Being a radiography student my main interest was in their radiography facilities and practices however I was also introduced to their emergency, obstetric and theatre settings assisting the local staff in their daily routines. Results: I could only describe the healthcare in this Nepalese hospital as an eye opener. Not only did I consider their hygiene levels to be poor but their radiation safety was non-existent. I experienced everything from trauma x-rays to childbirth, to the amputation of a hand and its dissection on the spot in theatre for the anatomical education of the interns. Conclusion: Volunteering as a student radiographer in Nepal has been an amazing experience and I have learnt so much in terms of medical procedures, health standards and safety within third world countries. I have gained an alternative perspective on medicine and healthcare, and the importance of basic standards and hygiene. I highly recommend volunteering to other students, not only did I learn so much but I gained a great respect for the health professionals working there and an insight into what it means to be a radiographer in a third world country.

Aim: After being approached by a University art and design student to investigate the possibility of x-raying some objects for an assignment, I became curious, could x-rays be defined as art? This poster explores my findings. Method: The literature has been explored in terms of the definition of art and cases where x-rays have been used as art. Results: The Aborigines have used x-ray rock art for thousands of years. The art is mostly of humans, animals and mythical beings. The Aborigines use the x-ray rock art to bond with sites and tap into the powers of the being depicted in the art. Everything from the pigments used, the internal structural detail and the multi layered form, have symbolic meaning.1 Conclusion: X-Rays are a form of art and x-ray rock art has been used by Aborigines for thousands of years. So what did the student and I x-ray for the assignment? Reference 1. Tacon PSC. The power of stone: symbolic aspects of stone use and tool development in Western Arnhem Land, Australia. Antiquity 1991; 65: 192–207.


286 Missed transient lateral patellar dislocation A McNamee and C Buchan Gold Coast University Hospital, Queensland, Australia

Scientific Exhibits Doctor, what’s the risk? Is our knowledge of radiation keeping up with technology? C Younger, S Bayliss, A McWilliam, C Ong and F Oh University of Newcastle, New South Wales, Australia

Aim: Transient lateral patellar dislocation (TLPD) is often missed on plain radiograph. Patients will often undergo further imaging, usually with MRI, following a period of time of knee pain and subsequent referral to an orthopaedic surgeon. In retrospect on review of the acute presentation radiograph the features of TLPD have not been recognised. The aim of this study is to recognise the features of TLPD on plain film resulting in earlier diagnosis and referral. Method: We retrospectively reviewed the initial knee radiographs of 29 patients diagnosed with TLPD by MRI between 01/01/12 and 10/02/14. The following data were collected: joint effusion and size, presence of an intra-articular body, fracture, lateral patellar translation, BlackburnePeel (B-P) index, Insall-Salvatti index and trochlear appearance if available. Results: 29 patients in total were diagnosed with TLPD on MRI during the time period. 18 males and 11 females aged between 13 and 58 with a mean age of 25. In 15 of these patients the diagnosis of patellar dislocation was missed. The number of days between radiograph and MRI ranged from 1 day to 210 days. 93% had large joint effusions (>10 mm) and 89% had patellar alta utilising the Insall-Salvatti index and 39% had patellar alta utilising the Blackburne-Peel index with the remainder of patients being normal. There were 57% fractures with 28% intra-articular bodies. 32% had radiographic evidence of patellar translation. In the group of patients in which TLPD was missed 87% had a large joint effusion and 93% had patella alta. Conclusion: 53% of patients with TLPD were not recognised on radiography. TLPD should be suspected if there is a large joint effusion and patellar alta present utilising the Insall-Salvatti index. Other secondary radiographic features of TLPD include an intra-articular body, fracture and patellar translation.

Aim: The purpose of this study was to investigate clinician and patient knowledge of radiation dose and the consequences of radiation. Subsequently the purpose was to determine whether this can be thought to be in line with the current level of utilisation of radiological procedures for diagnostic purposes. Method: A literature search was performed using online databases and search engines for articles reporting on referrers or patients radiation knowledge. Results: There is a lack of understanding of radiation dose and risks among clinicians and patients where the majority of clinicians greatly underestimate the dose for common imaging procedures. Furthermore, there is a lack of communication between referring clinicians and patients regarding the risks of radiation. Conclusion: An increase in ongoing education on radiation for clinicians and referrers should be introduced and complimented by automated pop-up systems that aim to increase a referrer’s awareness of either individual patient accumulated dose or general risk of high dose imaging procedures. This would provide clinicians with continued learning and reminders so that they may accurately educate patients about their examination and thus ensure that the patient is being given the right to make an informed decision on their health care. In addition, information pamphlets could be given to all patients receiving certain high dose x-ray procedures at referral appointments, so that they have time to assimilate and discuss the information before their examination. It is emphasised that a discussion prior to the examination, is essential to support the pamphlet and ensure that patients have a clear understanding of the radiation risks against the benefits of their examination.


Scientific Exhibits

287

CT brain perfusion: A phantom based study of image quality and dose S Midgley, D Stella, B Campbell, F Langenberg and

Dual energy X-ray analysis using synchrotron computed tomography at 35–60 keV S Midgley1 and N Schleich2

P Einsiedel

1

School of Physics, Monash University, Melbourne, Australia,

Melbourne Health, Victoria, Australia

2

Dept of Radiation Therapy, University of Otago, New

Zealand Aim: Image quality and radiation dose were measured using a phantom, Iohexol contrast agent, the CT perfusion (CTP) protocol and clinically relevant range of scan parameters. Methods: The CTDI head phantom [1] is a cylinder of perspex with 16 cm diameter and 10 mm holes at the centre and 3, 6, 9, and 12 o’clock positions. These were loaded with vials of Iohexol contrast agent diluted to 1–10% by weight which is typical following IV injection after dilution in the heart and lungs [2]. The study was conducted with a Siemens flash 128 scanner, the CTP protocol involving helical CT over 10 cm axial length at 70–120 kVp, 150–285 mAs and used imagej [3, 4] for analysis. Results: A skull attenuation correction produced a strong cupping artefact that thwarted quantitative analysis of all but the central region. This was eliminated by wrapping the phantom with a suitable attenuator. Image quality measurements used Hounsfield numbers (HN) as a measure of contrast produced by iodine relative to soft tissue, and noise as the standard deviation for regions in perspex. Results were presented as the contrast to noise ratio (CNR) versus CTDIvol representing the average dose per slice. Conclusion: For each iodine concentration, CNR is best at higher kVp where the CTDIvol is largest. These findings are explained with reference to the energy dependence of the mass attenuation coefficient [5]. Maximum contrast is conveyed above the absorption edge for iodine, or photon energies 33–50 keV. When considering the spectrum of transmitted photons [6] over the same energy range, the number of photons per unit CTDIvol decreases with kVp, so must be accommodated by increasing dose. Comparison between 70 and 80 kVp operation found lower kVp achieves the same CNR with less dose, or improved CNR at the same dose. References [1] IMPACT. Type testing of CT scanners: methods and methodology for assessing imaging performance and dosimetry – evaluation report MDA/98/25, Medical devices Agency, London 1998, p15–46. [2] AAPM report 15, Performance evaluation and quality assurance in digital subtraction angiography, American Association of Physicists in Medicine, American Institute of Physics, New York 1985, p19– 20. [3] Rasband WS. Imagej (US National Institute of Health, Bethesda, MD, USA 1997–2012). [updated 07 March 2014; cited 26 March 2014] Available from: http://imagej.nih.gov/ij [4] Schneider CA, Rasband WS, Eliceiri KW. NIH to imageJ: 25 years of image analysis. Nature Methods 2012; 9: 671–5. [5] Hubbell JH, Seltzer SM. Tables of x-ray mass attenuation coefficients 1 keV to 20 MeV for elements Z = 1 to 92 and 48 additional substances of dosimetric interest, NISTIR 5632 (National Institute of Standards and Technology, Gaithersburg, MD 1995) p1–79. [updated 9 December 2011; cited 26 march 2014]. Available from: http://www.nist.gov/pml/data/xraycoef [6] Boone JM, Siebert JA. An accurate method for computer generating tungsten anode X-ray spectra from 30 keV to 140 keV. Med Phys 1997; 24: 1661–70.

Aim: Dual energy X-ray analysis (DEXA) uses measurements of the X-ray linear attenuation coefficient at two photon energies to determine parameters that characterise the density and composition of materials. We used synchrotron radiation to gather mono-energetic CT data against which to validate a novel DEXA technique [1–5]. Method: Phantoms were prepared as liquid samples of known density and composition including ethanol-water mixtures and salt solutions (NaCl, NaH2PO4, MgCl2, MgSO4, KCl, KH2PO4 and CaCl2). The phantoms and an ex-vivo laboratory animal underwent mono-energetic CT at 35–60 keV using the Australian Synchrotron Imaging and Medical beamline and CCD camera optically coupled to a luminescent screen. Results: The CT data for the phantoms provided coefficients that describe attenuation as measured by the beamline, and expressed as elemental cross-sections. The latter were below the expected values for a narrow beam due to the detection of forward scattered radiation. The phantom data underwent DEXA, and the accuracy was quantified as a function of mean beam energy, dual energy separation, and elemental composition. The CT data for ex-vivo samples was spatially co-registered, subjected to DEXA, and the results were used to create volumetric maps representing the X-ray linear attenuation coefficients and energy absorption coefficients for photon energies of 10 keV to 10 MeV. Conclusion: At diagnostic energies, photon attenuation is controlled by the electron density and a statistical measure of elemental composition. The latter is derived from the fourth statistical moment (given as R4), which is related to the concept of effective atomic number. A novel DEXA technique was successfully demonstrated using samples of known density and composition, and factors that affect accuracy were identified [4, 5]. An important application, the prediction of photon interaction coefficients at other beam energies, was demonstrated for a biological specimen. References [1] Jackson DF, Hawkes DJ. X-ray attenuation coefficients of elements and mixtures. Phys Rep 1981; 70: 169–233. [2] Midgley SM. A parameterisation scheme for the X-ray linear attenuation coefficient and energy absorption coefficient. Phys Med Biol 2004; 49: 307–25. [3] Midgley SM. A model for multi-energy x-ray analysis. Phys Med Biol 2011; 56: 2943–62. [4] Midgley SM. Feasibility study for a novel method of dual energy x-ray analysis. Phys Med Biol 2011; 56: 5599–619. [5] Midgley SM. Feasibility study for DEXA using synchrotron CT at 20–35 keV. Phys Med Biol 2013; 58: 1085–205.


288 Evolving role of Magnetic Resonance Imaging (MRI) in the diagnosis, radiotherapy simulation and management of Mucosal Primary Head and Neck Cancer (MPHNC) M Min,1 M Lee,1 A Fowler,1 D Forstner,1 L Holloway2 and

Scientific Exhibits Work the World – Dar Es Salaam L Murray Royal Brisbane and Women’s Hospital, Queensland, Australia

G Liney2 1

Liverpool Hospital, Liverpool, New South Wales, Australia,

2

Ingham Institute of Applied Medical Research, Liverpool,

New South Wales, Australia Background: Following radiotherapy of MPHNC, locoregional recurrence is the predominant site of failure while response to therapy depends on microenvironment characteristics especially hypoxia. Functional imaging with Positron Emission Tomography (PET) is reported as a potential predictive and prognostic imaging biomarker for radiotherapy but there are still some limitations particularly with false positive results due to inflammation from radiotherapy. DiffusionWeighted MRI (DW-MRI) and Dynamic Contrast-Enhanced MRI (DCEMRI) are non invasive techniques assessing the response and changes in the microenvironment for tumours. Literature discussing the role of combined DW-MRI and DCE-MRI is scarce. More accurate models determining tumour response will help in future adaptive radiotherapy studies, particularly with respects to treatment escalation or de-escalation. To optimise therapeutic ratio in MPHNC, a dedicated MRI simulation is likely to improve target volume and organ-at-risk delineations of such a region with anatomically complex structures. Description of Our Study: The aim of our study is to determine the correlation of changes in DW-MRI and DCE-MRI with 18F-FDG PET and loco-regional tumour control of MPHNC receiving definitive radiotherapy. Imaging with FDG-PET and MRI will be obtained before, during and following radiotherapy. Imaging is being performed on an 80 cm wide-bore Siemens MRI on a flat bed couch with thermoplastic mask immobilisation and use of an 8 channel flex coil. Outcomes assessed will include tumour response at 3 months with FDG-PET and 12 month loco-regional control rates. Discussion: Since the acquisition of the first state-of-the-art MRI simulator in Australia, planning MRI simulations are being performed routinely for MPHNC radiotherapy and specific equipments including a 32 channel coil in the table and an 18 channel anterior coil have been purchased to improve radiotherapy planning processes. At the meeting, details of our project and our experience in the implementation of MRI in the radiotherapy simulation for MPHNC will be discussed.

Work the World is an organisation providing elective placements and projects abroad for student doctors, nurses, midwives, dentists, pharmacists, radiographers and physiotherapists. Staff work closely with numerous organisations and charities to allow programs to be tailored for each individual. In 2013 I undertook a 4-week placement with Work the World in Dar Es Salaam, Tanzania. I completed three weeks of my placement at the Muhimbili National Hospital, and one week in the Healthcare Centre in Melela village. The Muhimbili National Hospital Radiology department deals with around 100 patients per day, referred from the general wards, casualty, the specialist Orthopaedic Institute and other smaller hospitals in Dar Es Salaam. They provide results to assist in diagnosis and treatment for fractures, trauma, road traffic accidents and various chest infections, including tuberculosis and HIV related cases. As a student radiographer I was still developing my own set of radiographic techniques and values with respect to patient care. My placement at Muhimbili National Hospital was a very eye opening experience and allowed me to expand on these techniques and values. The five weeks of my trip were both the most challenging and the most rewarding weeks of my life. I am so grateful to the staff in the hospital and Work the World for providing me with this opportunity that I can now share.


Scientific Exhibits

289

A review of the QA history for five Varian linear accelerators R Murry

A radiobiological optimisation approach in VMAT prostate planning using RayStation B Mzenda1 and J Quach

Radiation Oncology Queensland, Queensland, Australia

1

Auckland Radiation Oncology, 2University of Auckland,

New Zealand Aim: To review the quality assurance history of five linear accelerators and provide evidence to inform changes to the QA process based on a risk management approach. Method: Quality assurance data for five Varian 2100 iX linear accelerators (linacs) have been collected over a their lifetimes (median = 4 years). A consistent set of routine QA measurements has been made over this time. Each linac has been tested with the same ion chambers, electrometers, build-up caps and phantoms. The data history were reviewed to identify any information or trends that might assist in predicting breakdowns, allow for pro-active linac adjustments or justify a reduction or re-scheduling of routine QA tasks. Results: The output varies significantly between energies and modalities within a single linac, and also varies between linacs. One linac had its monitor chamber replaced after 1735 days. The rate of increase of photon output for the 2nd chamber is higher (and significantly different, p = 0.00079) than for the original monitor chamber whereas the rate of increase of electron outputs is lower than for the original monitor chamber. Off-axis ratios for this linac (indicative of photon energy) started trending away from the baseline value post monitor chamber change; however this finding wasn’t supported by water tank measurements. Sliding window output factors for all tested linacs have been decreasing over time. They have not exceeded the tolerance but a universal trend appears evident that warrants further investigation. Conclusion: Reviewing quality assurance records for linear accelerators is a worthwhile activity. The implementation of the findings from this review on local physics practice is in progress and has highlighted the benefits of having electronic QA records that facilitate continual monitoring.

Aim: This study aims to compare prostate cancer treatment plans optimised by way of radiobiological objectives to corresponding plans generated using dose-volume based parameters for VMAT based treatments. Method: A total of thirty plans initially planned based on conventional physical parameters were retrospectively replanned based on radiobiological parameters using the RayStation treatment planning system (TPS). Radiobiological end-points based on tumour control probability (TCP) and normal tissue complication probability (NTCP) as well as dose-volume based metrics for target coverage and organ at risk sparing were used for assessing plan quality. In addition treatment plans generated in this study were used to investigate the biological effects of missed treatment fractions as well as strategies currently employed to correct for missed fractions. Results: Equivalent treatment plans have been attained in RayStation based on optimisations using radiobiological parameters to those optimised based on conventional parameters. Statistical analysis has been used to assess the significance of any differences observed whilst TCP and NTCP end-points as well as PTV (D98%, D50%, D2%) and rectum (V74, V70, V65, V60, V50) metric variations have been used to assess the plan quality equivalence. Conclusion: Radiobiological parameters can be applied to aid optimisations in prostate planning and directly related to expected clinical outcomes. In addition recommendations can be inferred from the radiobiological plan quality assessments to inform the efficacy of correction strategies for missed fractions.


290 The abdominal x ray, even less useful than previously thought V Navani1 and G Kamalasena2 1

John Hunter Health Network, 2Ryde Hospital, New South

Wales, Australia

Scientific Exhibits Changes in CT number of high atomic number materials with field of view when using an extended CT number to electron density curve and a metal artefact reduction reconstruction algorithm V Nelson and A Gray Macarthur and Liverpool Cancer Therapy Centres,

Aim: The abdominal x ray (AXR) has long been regarded as overused, with a low diagnostic yield (1). The emergency department (ED) at our facility was concerned regarding the perceived increased use of this imaging method amongst junior staff, when faced with a history of abdominal pain. Method: To evaluate this, a retrospective case history analysis was undertaken of all presentations to the ED that received a plain abdominal radiograph, for the last 3 calendar months of 2013. For each patient the: appropriateness of the scan (whether it met RANZCR endorsed indications from the Royal Perth Hospital), correlation of AXR report to primary discharge diagnosis and undertaking of further imaging was assessed. Results: Of the 120 patient records identified, all were available for analysis. Only 50 (42%) met the indication criteria. 22 (18%) of all the AXRs had a report diagnosis that correlated with the discharge diagnosis. 17 (14%) patients had AXRs that were then followed by CT scans. Of the AXRs that met the indication criteria, 12 (24%) had a report that correlated with the discharge diagnosis, leaving 12 (17%) AXRs that did not meet the indication criteria having a report that correlated with the discharge diagnosis. Conclusion: Though small, with relatively crude measurements of AXR worth, this study shows that few AXRs are performed appropriately, with even those that are indicated often not adding to the discharge diagnosis. Furthermore a reasonable proportion of patients undergoing AXR were then exposed to further radiation with a CT scan. The low diagnostic yield, relatively high likelihood of further imaging and often inappropriate use of AXRs makes them an increasingly less useful tool in the 21st century ED.

New South Wales, Australia Aim: Algorithms such as O-MAR (Orthopedic Metal Artifact Reduction1) aid contouring and 16-bit images increase the range of CT number and may allow more accurate estimation of dose in tissues surrounding high Z materials, however the CT number of high Z materials change when these are applied2,3. This study investigated the impact of field of view (FOV) on CT numbers of high Z materials when using these algorithms. Method: CT scans were performed at 120 kV on a CT number to electron density (ED) phantom (Gammex RMI) with titanium and steel inserts for two scanning protocols with different FOV (brain and pelvis). 12-bit and 16-bit reconstructions were performed, with and without O-MAR. CT-ED curves obtained were compared. A planning study was also performed. Results: The average difference in CT numbers for tissue equivalent materials between the brain and pelvis protocols was −8 ± 17 (1 SD). CT-ED curves differed beyond EDs of 1.695 (cortical bone), due to the saturation of the CT numbers for the metal inserts in 12-bit images, Fig. 1. For 16-bit images larger differences were observed. For O-MAR images, CT numbers for the pelvis protocol were lower than the brain protocol by 476 for titanium and 2028 for steel. Comparing between standard and O-MAR pelvis reconstructions, the difference was −94 for titanium and 345 for steel. A change in CT number from ∼12500 to ∼14500 for a 1 cm diameter insert produced a 4% dose difference at points beyond the insert.

Reference 1. Lee PW. The plain X-ray in the acute abdomen: a surgeon’s evaluation. Br J Surg 1976 Oct; 63(10): 763–6.

Fig. 1. CT number to ED curves.

Conclusion: The CT-ED curve for the 16-bit images can be applied for images with or without the O-MAR correction where beams pass through tissue. Further investigation is required to assess the accuracy of the dose calculation when beams pass through metal and the reason for the difference in CT numbers observed between the brain and pelvis protocols.


Scientific Exhibits

References 1. Philips Health Care Metal Artifact Reduction for Orthopedic Implants (O-MAR). USA. Philips CT Clinical Science. Available from: http://clinical.netforum.healthcare.philips.com/us_en/Explore/ White-Papers/CT/Metal-Artifact-Reduction-for-OrthopedicImplants-%28O-MAR%29. 2. Glide-Hurst C, Chen D, Zhong H, Chetty IJ. Changes realized from extended bit-depth and metal artifact reduction in CT. Med Phys 2013; 40(No 6): p061711. 3. Spadea MF, Verburg J, Baroni G, Seco J. Dosimetric assessment of a novel metal artefact reduction method in CT images. J Appl Clin Med Phys 2013; 14(No 1): p 299.

291 Synchronous prostate and rectal adenocarcinomas irradiation utilising volumetric modulated arc therapy (VMAT) S Ng,1,2 C Sale,2 T Tran,2 P Moloney2 and R Lynch2 1

Peter MacCallum Cancer Centre, Melbourne, Australia,

2

Department of Radiation Oncology, Andrew Love Cancer

Centre, Barwon Health, Geelong, Australia Aim: To demonstrate the advantages and outcome benefits of Volumetric Modulated Arc Therapy (VMAT) for a synchronous prostate and rectal adenocarcinoma case. Method: A 69-year-old man was initially diagnosed with cT2bN0M0 intermediate risk prostate cancer and was referred for definitive radiation therapy. He had fiducial markers inserted; however, post-insertion he developed rectal bleeding and on further investigation was diagnosed with a T3N1M0 rectal adenocarcinoma. He required radiotherapy treatment for both his prostate and rectal primaries. He was treated for his rectal primary with combined radiotherapy and continuous 5-fluorouracil and for his prostate cancer with six months of neoadjuvant hormones and radiotherapy. Radical radiotherapy was prescribed to 50.4 Gy in 28 fractions to both the prostate and rectum, followed by a further 24.0 Gy in 12 fractions to the prostate only. A VMAT technique was utilised to make this complex treatment plan possible (Figure 1). Treatment-related toxicities and follow up were documented using the National Cancer Institute (NCI) Common Terminology Criteria for Adverse Events (CTCAE) criteria.

Figure 1 Dose distribution for the VMAT plan for the synchronous prostate and rectal adenocarcinoma case.

Results: Final histopathology from abdomino-perineal resection for rectal cancer confirmed complete response to neo-adjuvant treatment. At 12 months, the patient achieved complete response for both rectal and prostate cancers without significant treatment-related toxicities. His Prostate Specific Antigen (PSA) and Carcino-Embryonic Antigen (CEA) levels remained within normal limits to date and staging scans demonstrated no signs of disease recurrence. This patient reported satisfactory bladder and bowel function at 12 months post-irradiation. Conclusion: This case demonstrates the possible role of VMAT technique in synchronous prostate and rectal cancers treatment with positive outcomes for the patient.


292

Scientific Exhibits

Strengthening brachytherapy programs with ultrasound (US) quality assurance (QA) T Nguyen, Y Tran and V Seshadri

Evaluation of patient specific quality assurance techniques with Oncentra Masterplan and Varian iX S Nilsson, Z Moutrie and N Yu


Cancer Care Service, Royal Brisbane and Women’s Hospital, Queensland, Australia

Aim: US QA testing in Brachytherapy is not mandatory in Australia, however, to strengthen the Brachytherapy service quality, an US QA program following the AAPM Task Group (TG) 1281 recommendations using the CIRS© 045 Brachytherapy QA Phantom (CIRS 045) was critiqued. The AAPM TG 128 recommendations were also performed in tap water and saline (0.9% w/v sodium chloride) phantoms with different acoustic properties compared to soft tissue, to test which recommendations can be validated and compared to the performance of CIRS 045. Method: AAPM TG 128 recommendations were tested using a BK Medical© FlexFocus 800 ultrasound scanner, BK Medical Endocavity Biplane 8848 transducer attached to a CIVCO EX3™ Stepper, the CIRS 045 and ultrasound gel for coupling. Tests were repeated using 5 × 18 gauge needles inserted through 2 × Template Grids for stabilisation submerged in the tap water and saline phantoms. Results: The CIRS 045 made of Zerdine®, with matching acoustic velocity to soft tissue, performed all test recommendations with sub millimetre accuracy. The liquid phantoms only performed 3 recommendations and could not match the CIRS 045 performance. With a greater acoustic velocity1, the saline phantom gave more accurate results than the tap water phantom, which failed baseline action level. When a purpose built phantom is not available, a saline phantom is more reliable option than a tap water phantom in performing US QA, however neither option meets all AAPM TG 128 recommendations. Conclusion: While US QA is not mandatory in Australia, following the AAPM TG 128 recommendations adds to the robustness to a brachytherapy quality program. The paper has determined that the CIRS 045 Brachytherapy QA Phantom meets all AAPM TG 128 recommendations, and now forms part of the regular QA program in the brachytherapy service.

Aim: To develop patient specific quality assurance technique that is efficient and effective for step-and shoot approach IMRT as per TG 119(1). Method: Dose measurement was taken with two 2D detector arrays with different spatial resolution to see what role they can have in patient specific quality assurance with Oncentra MasterPlan and Varian iX. EDR2 film and point dose measurements with an ion chamber were used as benchmarks. Gamma analyse tools were used to quantitatively compare dose distribution. Different match criteria were compared to determined appropriate settings to identify the 2D arrays limitations to detect relevant clinical errors. Clinical performance of the 2D arrays for relative and absolute dosimetry was demonstrated with five beams 6 MV prostate and head and neck IMRT plans with varying level of complexity. Results: In all patient plans investigated, the film measurements were found to have a higher sensitivity compared to the detector arrays. One detector array demonstrated to be more sensitive then the other. Conclusion: Both 2D detector arrays offer a possibility for both performing relative and absolute dose measurements. One detector array showed to be more suitable to detect errors in plans with higher complexity. Reference 1. Ezzell GA, Burmeister JW, Dogan N et al. IMRT commissioning: Multiple institution planning and dosimetry comparisons, a report from AAPM Task Group 119. Medical Physics 2009; 36(11): 5359– 73.

Reference 1. Pfeiffer D, Sutlief S, Feng W, Pierce H, Kofler J. American Association of Physics in Medicine Task Group 128: quality assurance tests for prostate brachytherapy ultrasound systems. Medical Physics 2008; 35: 5471–89.


Scientific Exhibits Breast cancer Axillary ultrasound – are we doing it right? K Okawa1 and P Dixon2 1

Wellington Hosptial, 2Palmerston North Hospital,

New Zealand

293 Transforming curriculum through technology – reflecting on a decade of flexible delivery in a radiation therapy program C Osborne, C Wright and K Knight Monash University, Victoria, Australia

Aim: To measure the accuracy of Axillary ultrasound in the detection of abnormal lymph nodes in patients with breast cancer. Method: A retrospective analysis was performed on 194 consecutive patients diagnosed with primary breast cancer that underwent mastectomy or Wide local excision between 1/1/2010 to 31/12/2011 in Palmerston North. For each patient we collected the Ultrasound report and images, Biopsy histology result if performed and type of lymphadenectomy surgery. Patients were excluded if they had neoadjuvant chemotherapy prior to surgery, if they had previously treated breast cancer in the same breast or if they had multiple cancers or cancer over 3 cm in size and only underwent SLNB without ALND. (There are limited trial results to support the use of SLNB in cancers over 3 cm in diameter and in multicentric/multifocal tumours [1]. Therefore currently SLNB cannot be assumed gold standard for these tumours.) Results: Out of the 120 cases that had axilla scanning, 100 (83.3%) were reported as normal or were normal on the reviewed images. 67 of these cases were true negatives with a negative predictive value of 67%. Abnormal lymph nodes were reported in 20 (16.7%) cases, 18 of which were true positives resulting in a positive predictive value of 90%. Of the 157 total cases, 60 (38.2%) were found to have lymph node metastases after SLNB and/or ALND. Of these, 51 (85.0%) had had their axilla scanned preoperatively. The metastases were detected on Ultrasound in 18 of the 51 case with sensitivity of 35.3% and a specificity of 97.1%. Conclusion: In our department, the sensitivity for detection of abnormal lymph nodes is below international standards of 48.8–87.1% [2]. There is a need to review the morphological criteria of abnormal lymph nodes with less emphasis on size. References 1. Spillane A, Brennan M. Accuracy of sentinel lymph node biopsy in large and multifocal/multicentric breast carcinoma: a systematic review. EJSO 2011; 37: 371–85. 2. Alvarez S, Anorbe E, Alcorta P, Lopez F, Alonso I, Cortes J. Role of sonography in the diagnosis of axillary lymph node metastases in breast cancer: a systematic review. AJR 2006; 186:1342–8.

Background: The Master of Medical Radiations in Radiation Therapy (MMRRT) is a unique graduate entry program, which was the first of its kind in Australia. It is delivered by distance education, over two calendar years, incorporating 63 weeks of clinical placement. This flexible mode of delivery makes it ideal for clinical centres in regional and remote areas of Australia that find recruitment and retention of students and staff a challenge. However, with this model they can recruit local students and retain them in the workforce post-graduation. The program commenced in 2003 with the majority of theoretical content being delivered as hard copy material, supported with an on-line learning platform for discussion and reflection. Over the past decade, there have been significant advances in curriculum delivery, including use of the VERT simulated learning environment and a greater emphasis on the use of electronic learning systems and resources, such as on-line assessment and ‘real-time’ on-line support sessions. This paper describes how the curriculum has evolved to embrace these innovations and new electronic technologies. It discusses how we have adapted technology to provide a flexible and positive learning environment for distance education students, whilst continuing to provide a quality program. Method: This paper is a commentary and critical reflection with respect to current literature on how curriculum delivery has evolved in the electronic era. A review of the literature was undertaken on electronic databases to support the authors’ reflections. Results/Conclusion: New educational technologies have had a significant impact on curriculum delivery for our distance education program. Implementation of these technologies is resource intensive in the first instance, however student support has been strengthened. As there continues to be an increase in the rural and regional radiation therapy service across Australia, our innovative program will continue to adapt to provide a flexible but robust model of radiation therapy education.


294 Case report of a fractured dental root in the maxillary ostium M Osman,1 A Mohamed,2 B Robertson,3 G Chu3 and W Law2 1

Logan Hospital, Brisbane, Australia, 2Department of

Scientific Exhibits Wrong place, wrong time: Imaging and embryological features of congenital renal anomalies M Osman,1 M Skalski,2 I Bickle,3 H Knipe4 and F Gaillard4 1

Logan Hospital, Brisbane, Australia, 2Southern California

Radiology, Princess Alexandra Hospital, Brisbane, Australia,

University of Health Sciences, Los Angeles, California,

3

United States of America, 3RIPAS Hospital, Bandar Seri

Department of Maxillofacial Surgery, Princess Alexandra

Hospital, Brisbane, Australia

Begawan, Brunei, 4The Royal Melbourne Hospital, Melbourne, Australia

Aim: To report a rare case of maxillary sinus obstruction due to a displaced dental root fracture fragment within the ostium. A brief review of the clinical presentation, imaging findings, potential complications and management of displaced maxillary dental root fragments is presented. Method: We present the case of a young man who underwent dental extraction of the 26 molar during which the tooth root was fractured and the fracture fragment expulsed into the left maxillary sinus. Subsequent migration of the fragment to the ostium resulted in obstruction of mucus drainage and assessed with facial computed tomography. The root fragment was removed surgically without complication. Results: The clinical presentation, imaging findings, potential complications and management of dental root fragments in the maxillary sinuses are discussed. Conclusion: The expulsion of fractured dental roots into the maxillary sinuses is a potential complication of dental extraction. In most cases the root fragment is situated within the body of, or on the floor of the maxillary sinus. In rare cases the fragment may migrate superiorly toward the ostium which can obstruct the drainage of mucus. This may lead to complications such as infection or mucocoele formation. Surgical removal is usually necessary even in asymptomatic patients due to the risk of infection or other complications.

Aim: To recognise the imaging appearances of a variety of congenital renal anomalies resulting from abnormal renal migration and fusion, and to better understand the causative error in embryological development. Method: In this pictorial review, high quality original medical illustrations will be presented together with multi-modality imaging, to demonstrate the abnormal embryological development that gives rise to the typical appearances of several congenital renal dysmorphisms, focusing on fusion anomalies and ectopia. Results: During embryogenesis, failure of migration and fusion of the kidneys results in a spectrum of congenital anomalies characterised by abnormal renal location, fusion or both. Recognition of these anomalies and an understanding of the embryological development that gives rise to these conditions is challenging but essential in making a correct diagnosis. Conclusion: The array of congenital renal anomalies is vast. Correct diagnosis relies on understanding the abnormal embryological development of the kidneys and the recognition of such anomalies.


Scientific Exhibits

295

A single-centre retrospective analysis of the incidence of seromas post-lumpectomy in patients requiring radiation therapy for the management of breast cancer S Oultram1,2 and S Dempsey2

M Foote1

1

1

Calvary Mater Newcastle, Department of Radiation 2

Sensorineural hearing loss: Who is most at risk and what can we do about it? P Shorter,1 F Harden,2 R Owen,3 B Burmeister1 and Department of Radiation Oncology, Princess Alexandra

Oncology, University of Newcastle, Faculty of Health and

Hospital, 2Queensland University of Technology,

Medicine, School of Health Sciences, New South Wales,

3

Australia

Mater Centre, Queensland, Australia

Aim: This project forms part of a larger research higher degree study investigating the utility of the Clarity™ 3D Ultrasound (US) system in detecting post-lumpectomy breast seromas, and its use in the simulation and treatment of electron boost radiation therapy for early stage breast cancer. A post-lumpectomy breast seroma is a collection of serous fluid that can be used as a proxy for the primary breast cancer tumour site.(1, 2) This study specifically seeks to analyse the CT-simulation data to quantify the incidence of, and describe the presence of, seromas detectable on CT. Method: A retrospective clinical audit was undertaken on the CT data sets of early stage breast cancer patients treated in 2013 at the Calvary Mater Newcastle to identify the presence of seromas. Saturation sampling was used to identify a sample of CT data sets that represented all patients with Stage 1 and 2 breast cancers. Demographic data collected included: Age; weight, height or BMI; bra size; referring surgeon; tumour characteristics, tumour size on diagnostic US post-excision, and seroma volume as contoured by the Radiation Oncologist at planning, as part of the standard voluming procedure. A Radiation Therapist (RT) reviewed all seroma volumes and determined a level of difficulty in the detection based on visual appearance. Results: A seroma was identified on the CT data in a large proportion of patients. Although the presence of a seroma was obvious in the majority of cases, the detection was problematic in several cases with the RT requiring additional training to differentiate between the seroma and surrounding tissues. Conclusion: This research confirms that a seroma can be detected on CT data by RTs. The next phase of this research is a prospective study which will attempt to correlate the detection of seroma using nonionising US with that of CT. The results from this next study may substantiate the use of US in the localisation of breast seromas in planning and delivery of boost radiation therapy.

Background: Patients with virally mediated head and neck cancer (HNC) are often long term cancer survivors. Therefore, research is being directed towards minimising side effects and improving patient quality of life (QOL). Ototoxicity is a known complication for patients with HNC receiving Cisplatin-based chemoradiation (CbCRT). This study sought to identify potential risk profiles for patients most at risk of developing sensorineural hearing loss (SNHL). Methodology: One hundred and fifty patients with HNC who received CbCRT, with curative intent, were retrospectively reviewed. The impact of diagnosis, chemotherapy regimen, radiation dose, accuracy of inner ear delineation and dose to critical inner ear structures, were evaluated. Sensorineural hearing function was assessed using pure tone audiometry. SNHL was diagnosed if a clinical significant change of >10 dB was present in the patient’s bone conduction threshold test, across any of the key human speech frequencies. Results: Of the one hundred and fifty patients reviewed, fifty-two (34.7%) patients received baseline and follow up audiograms during their treatment. Seven (13.5%) patients had pre-existing SNHL. Following CbCRT, forty-two (80.8%) of these patients were diagnosed with or had worsening SNHL, four (7.7%) patients were diagnosed with mixed hearing loss and six (11.5%) patients results indicated that hearing was within normal limits. Diagnosis in patients with SNHL included disease involving the: oropharynx (61.9%); larynx (14.3%), hypopharynx (9.5%); oral cavity (7.1%), nasopharynx (4.8%) and paranasal sinus (2.4%). Chemotherapy regimen, radiation dose to inner ear structures and nodal involvement were all correlated with SNHL diagnosis. There was high variation in the accuracy of inner ear delineation between patients, including average volume, position and structures contoured. Conclusions: In this study, a significant proportion of patients developed SNHL following CbCRT for HNC. The proportion of patients with SNHL may be under reported without routine audiometry. These findings will be considered in a future prospective radiotherapy study.

Department of Radiation Oncology, Radiation Oncology

References 1. Agrawal A, Ayantunde AA, Cheung KL. Concepts of seroma formation and prevention in breast cancer surgery. ANZ Journal of Surgery 2006; 76(12): 1088–95. 2. Reitsamer R, Peintinger F, Kopp M, Menzel C, Kogelnik HD, Sedlmayer F. Local recurrence rates in breast cancer patients treated with intraoperative electron-boost radiotherapy versus postoperative external-beam electron-boost irradiation. A sequential intervention study. Strahlentherapie und Onkologie 2004; 180(1): 38–44.


296

Scientific Exhibits

Evaluation of prostate oedema following permanent fiducial marker insertion in prostate cancer patients treated at the Townsville Cancer Centre (TCC) D Patel and A Tan

Alfred Health’s CT quality control program A Perdomo, Z Brady, N Tran, L Hudson and K Provis

Townsville Cancer Centre, Queensland, Australia

Aim: Alfred Health operates five multi-detector computed tomography (MDCT) scanners of various models across two campuses for diagnostic imaging. A multi-faceted, multi-disciplinary approach has been established to optimise radiation dose and image quality. Method: Radiographers perform routine quality control (QC) in the form of daily noise and uniformity checks which are acted upon immediately if the results are out of tolerance. Alfred Health also participates in the Australian Radiation Protection and Nuclear Safety Agency (ARPANSA) Australian National Diagnostic Reference Level (NDRL) survey and the Royal Australian and New Zealand College of Radiologists (RANZCR) CT Image Review Self Audit. The Australian NDRL survey is completed annually by the radiographers and coordinated by the physicists while the Image Review Self Audit is completed every three years by the radiographers and radiologists and coordinated by the physicists. The findings of these QC activities are discussed at the multi-disciplinary CT Round Table which meets quarterly and includes radiographers, radiologists and physicists. Results: Daily noise and uniformity checks provide a method of predicting the need for an unscheduled service and ensuring that the systems remain within manufacturer specifications. The Australian NDRL survey allows comparison with the current Australian NDRLs as well as tracking doses over time to identify any changes and areas of concern. The Image Review Self Audit allows image quality to be tracked over time and indentify any areas of concern. Conclusion: A multi-faceted, multi-disciplinary approach is required to ensure a successful CT QC program.

Aim: To demonstrate that prostate oedema following fiducial marker (FM) insertion in prostate cancer patients is not of sufficient magnitude to require a one-week interval between insertion and treatment simulation. Method: Currently at TCC, prostate patients have three FM inserted into the prostate gland by a radiation oncologist who has undergone training in the procedure. Immediately after insertion, a verification CT scan (VCT) is performed in the treatment position to ensure correct FM placement. Formal planning CT (PCT) is delayed by one week to allow for traumatic oedema to subside. The datasets from 20 patients were examined to determine how well the prostate volume seen on VCT correlated with PCT. Volumes were delineated by a single radiation oncologist, blinded to whether each scan was VCT or PCT; planning target volumes were created and named PTVv and PTVp accordingly. PTVv and PTVp were compared. If no more than 5% of the PTVp was outside PTVv, the PTVv was considered to be adequate for clinical use. Results: Interim analysis shows no significant difference in the PTV volumes, with final analysis underway. This presentation will detail final results and the recommendation to come from this study. Conclusion: Preliminary results suggest there is no significant difference in PTVv and PTVp, final results will be presented at the meeting. If it can be demonstrated that the PTV derived from VCT is not significantly different from the PCT, it may be possible to use the VCT for radiotherapy planning and calculations. This would be significantly more convenient and cost-effective for patients and reduce the workload on our department.

Alfred Health, Victoria, Australia


Scientific Exhibits

297

TROG 10.01 bladder online adaptive radiotherapy: feasibility of bladder volume variance to predict plan-of-the-day suitability in daily online adaptive radiotherapy treatment D Pham,1 T Kron,2,3 M Bressel4 and F Foroudi3,5

A case study: The treatment of a solitary melanoma metastase of the frontal lobe using flattening filter free beams L Pham,1 T Moodie,3 R Beldham-Collins,1,2 R Chelvarajah,1

1

1

L D’Souza,1 J Harris,1 W Wang,1,2 R Gajewski1 and W Smith1

Department of Radiotherapy Services, Peter MacCallum 2

Crown Princess Mary Cancer Centre Westmead, 2Nepean

Cancer Centre, Melbourne, Australia, Department of

Cancer Care Centre, 3Westmead Cancer Care Centre

Physical Sciences, Peter MacCallum Cancer Centre,

Hospital, New South Wales, Australia

Melbourne, Australia, 3Sir Peter MacCallum Department of Oncology, University of Melbourne, Melbourne, Australia, 4

Department of Biostatistics, Peter MacCallum Cancer

Centre, Melbourne Australia, 5Division of Cancer Imaging and Radiation Oncology, Peter MacCallum Cancer Centre, Melbourne, Australia Aim: The aim of this study was to investigate whether a high level of variation in bladder volume from the first week of radiation treatment can predict whether a patient is suitable for adaptive radiotherapy for bladder cancer. Methods: Patients recruited into a Trans-Tasman Radiation Oncology Group trial of bladder online adaptive radiotherapy (1) were used for analysis. The planning CT and the bladder volume from the first five fractions were used to calculate the average bladder volume. The % standard deviation (SD) volume of the average bladder volume was calculated. The occasions whereby a patient had an adaptive plan unsuitable for treatment or a PTV margin insufficiently covered was recorded. Results: From August 2010 to December 2012, four-nine patients were recruited into the trial for analysis. Preliminary analysis of the first 38 (of 49) patients revealed that the average bladder volume was 100.1 cc. The mean % SD of bladder volume within the first six imaging was 17.9% (4.32–43.2). Across the whole group the conventional plan was used 2.5% of fractions due to the adaptive plan not being suitable. In the same group post-treatment imaging showed inadequate margin coverage on 14 of 253 occasions. Preliminary data show no correlation between the degree of variation within the first six imaged bladder volumes and unsuitability of an adaptive plan (r = 0.1, p = 0.632) or insufficient PTV margin (r = 0.1, p = 0.61). Conclusion: Analysis of the preliminary data suggests that the variation of the first six bladder volumes used to create a plan library for adaptive radiotherapy treatment is unable to predict occasions where an adaptive technique cannot be used or when reduced planning margins is insufficient.

Introduction: A 75 year old male with a history of metastatic melanoma with extra cranial disease only, presented with declining mobility after two cycles of Ipilimumab, a scan showing a single solitary brain metastases. Due to the multiple co-morbidities of this patient, he was not a suitable candidate for surgery and was referred for Stereotactic Radiosurgery of the brain. Method: The patient was to receive a single fraction Stereotactic conformal non coplanar radiosurgery treatment using a 6X flat beam and dose rate of 600 Mu’s/min. Due to the patient’s size the department’s Brain lab CT Localiser Frame was unable to be used and a different approach needed to be sought. The desired approach needed to be able to accurately deliver a 15 Gy single fraction in a short amount of time with imaging capabilities available to confirm treatment setup. The patient was immobilised using an IMRT Reinforced Thermoplastic Mask and Mould care cushion. A plan was created utilising the departments newly commissioned Flattening Filter Free Beams. Two 10X coplanar partial VMAT arcs were planned to deliver 15 Gy/1 fraction. Results: The patient’s treatment was completed in twenty minutes, with three minutes in total used to treat the two partial arcs with a dose rate of 1200 Mu’s/min. Kilovoltage images were taken, matched and shifts applied. A pre-treatment CBCT was then taken and auto matched showing a deviation of less than or equal to 1 mm in all three directions. Conclusion: Flattening Filter Free Beams are ideal for treatment of solitary brain tumours that require a large single fraction dose in a short amount of time with the additional benefit of a reduced integral dose to the patient outside of the treatment volume.

9 7mm PTV Margin Failure

8

ART Plan Not Sufficient

7

Frequency

6 5 4 3 2 1 0 0.00

5.00

10.00

15.00

20.00

25.00

30.00

35.00

40.00

45.00

50.00

Bladder Volume Standard Deviation (%)

Reference 1. Foroudi F, Pham D, Rolfo D et al. The outcome of a multi-centre feasibility study of Online Adaptive Radiotherapy for Muscle Invasive Bladder Cancer TROG 10.01 BOLART. Radiotherapy and Oncology (Accepted 6th March 2014).


298

Scientific Exhibits

A phase II pilot study of dose-reduced and fully fractionated stereotactic radiotherapy (FSRT) for juxtapapillary choroidal melanoma (JPCM). An open prospective clinical trial C Phillips,1 J McKenzie,2 W Campbell,2 O Martin,1 1

2,3

Assessing the intra-fraction motion for patients undergoing radical radiation therapy to the prostate with gold fiducials P Pichler,1 J Simpson,1,2 J Lehmann1,3 and P Greer1,2 1

Calvary Mater Hospital, Newcastle, 2University of

M Bressel and A Haworth

Newcastle, 3University of Sydney, New South Wales,

1

Australia

Peter MacCallum Cancer Centre, St Andrew’s Place, East

Melbourne, 2Royal Victorian Eye and Ear Hospital, Victoria Parade, East Melbourne, 3Sir Peter MacCallum Department of Oncology, University of Melbourne, Melbourne, Victoria, Australia Aim: We describe our preliminary experience using 70 Gy in 35 fractions photon radiotherapy to treat six patients with juxtapapillary choroidal melanoma (JPCM) and outline a currently open clinical trial in which we aim to determine if reduced-dose radiotherapy delivered in 2 Gy fractions can improve the therapeutic ratio of FSRT for JPCM without compromising distant metastasis free survival. Method: Six patients were treated with 70 Gy in 35 fractions from 2004 to 2010, a 3-D conformal technique1 (3D CRT) was used for three and stereotactic radiotherapy (FSRT) for the latter three. For the prospective phase II pilot study, 20 patients will be accrued. Eligible patients have primary JPCM, ECOG 0-2, are aged up to 70 and have visual acuity better than 6/60 (0.1). Important exclusion criteria are previous treatment for choroidal melanoma, metastatic disease, type II diabetes mellitus and non-malignant disease of the eye that may affect vision. All patients will be treated to 60 Gy in 30 fractions with FSRT using a frameless stereotactic system and a specialised light and camera eye-immobilisation system.2 The primary endpoint of the trial is 5 year distant metastasis-free survival. Secondary endpoints are freedom from progression in the treated eye, enucleation rate, visual acuity and late radiation toxicity. An exploratory substudy of tumour radiation sensitivity, using tissue obtained at optional tumour biopsy, will be undertaken using the γ-H2AX assay.3 Results: 5 of the 6 tumours are controlled after fully fractionated radiotherapy. No patients have metastases. Details of treatment, tumours and vision outcomes will be presented. A detailed explanation of the trial rationale, FSRT technique and an update of trial progress will be provided for the annual meeting. Conclusion: This approach represents a radical shift from the current standard treatment of CM, which uses radioablative doses of 50 Gy to 70 Gy in five fractions of 10 to 14 Gy over 1 to 2 weeks. This trial will open for accrual in mid-2014. It is funded by an RANZCR grant. References 1. Phillips C, Pope K, Hornby C, Chesson B, Cramb J, Bressel M. Novel 3D conformal technique for treatment of choroidal melanom with external beam radiotherapy. J Medical Imaging Radiat Oncol 2013; 57: 230–6. 2. Bogner J, Petersch B, Georg D, Dieckmann K, Zehetmayer M, Potter R. A non-invasive eye fixation and computer-aided eye monitoring system for linear accelerator-based stereotactic radiotherapy of uveal melanoma. Int J Radiat Biol Oncol Biol Phys 2003; 56: 1128–36. 3. Ivashkevic A, Redon CE, Nakamura AJ, Martin RF, Martin OA. Use of the γ-H2AX assay to monitor DNA damage and repair in translational cancer research. Cancer Lett 2012; 327(1–2): 123–33. doi: 10.1016/j.canlet.2011.12.025

Aim: (1) To quantify the intra-fraction motion of the prostate for the population treated at our clinic, (2) To assess the suitability of the current margin model and further develop a protocol based on our own institutional data. Method: One-hundred patients at the Newcastle Calvary Mater Hospital undergoing radical radiation therapy to the prostate with implanted gold fiducials had a set of pre and post treatment kV images using the Varian OBI system to identify intra-fraction prostate movement at each of their treatment fractions. Of the patients, 20 had treatment using 3DCRT, 79 with IMRT and one with VMAT. Results: The mean (and standard deviation) anterior-posterior, leftright and superior-inferior intra-fraction errors in cm were −0.07 (0.11), −0.01 (0.06) and 0.07 (0.10), respectively. Applying our data to a standard population based margin recipe1 suggests a uniform PTV expansion of 4 mm, however our data also reveal intra-fraction motion exceeding 4 mm for >30% of the whole treatment course in 25 patients and >50% of the whole course in 7 patients. No significant difference was detected between the 3DCRT, IMRT or VMAT treatment groups. Conclusion: Our intra-fraction motion for radical prostate therapy treatment with implanted gold fiducials is similar to that described in the literature. Previous studies of a similar nature2 have stated that appropriate CTV – PTV margins can be estimated from the results of the first five fractions of treatment. However, analysing the difference in intrafraction motion during the first five fractions and subsequent fractions we found cases in which this would have led to a severe under-dosing of the CTV. We also found that for a significant subgroup of patients, strict adherence to a population based margin would be inappropriate and thus patient specific intra-fraction motion management would be beneficial for these patients. References 1. Van Herk M, Remeijer P, Rasch C, Lebesque JV. The probability of correct target dosage: dose-population histograms for deriving treatment margins in radiotherapy. Int J Radiation Oncology Biol Phys 2000; 47(No.4): 1121–35. 2. Kron T, Thomas J, Fox C et al. Intra-fraction prostate displacement in radiotherapy estimated from pre- and post-treatment imaging of patients with implanted fiducial markers. Radiotherapy and Oncology 2010; 95: 191–7.


Scientific Exhibits

299

The AVIATOR trial: A multicentre phase II randomised trial of audio-visual investigation advancing thoracic radiotherapy S Pollock,1 K Makhija,1 R O’Brien,1 V Gebski,2

MRI protocols for the screening of manifestations of von Hippel Lindau disease in the at risk and/or genetically proven population D Rabinowitz,1 S Morris,1 J Kelly1 and K Tucker2

F Hegi-Johnson,3 J Ludbrook,4 A Rezo,5 R Tse,6 T Eade,7 8,9

5

1 4

Prince of Wales Hospital, Medical Imaging, 2Prince of

R Yeghiaian-Alvandi, , E Seymour, K Francis, P Greer,

Wales Hospital, Medical Imaging, 3St George Hospital,

S Roderick7 and P Keall1

Hereditary Cancer Clinic, New South Wales, Australia

1

3

2

University of Sydney, Sydney Medical School, University of

Sydney, 3Central Coast Cancer Centre, Gosford Hospital, 4

Department of Radiation Oncology, Calvary Mater

Newcastle Hospital, 5Capital Region Cancer Service, The Canberra Hospital, 6Chris O’Brien Lifehouse, Radiation Oncology, 7Northern Sydney Cancer Centre, Royal North Shore Hospital, 8The Crown Princess Mary Cancer Centre, Westmead Hospital, 9Nepean Cancer Care Centre, Nepean Hospital, New South Wales, Australia Purpose: Irregular breathing can exacerbate errors in medical imaging and radiotherapy. The audiovisual (AV) biofeedback system is an advanced form of breathing training that has been proposed to facilitate regular patient respiration. The purpose of the AVIATOR trial is to test the hypothesis that AV biofeedback will improve breathing regularity and reduce imaging errors for lung cancer patients’ radiotherapy. Methods: AVIATOR will accrue 75 lung cancer patients in seven radiation oncology sites; the goals of the AVIATOR trial are to assess patient & clinician experience with AV biofeedback, patient benefits, impact on image quality, treatment margins, and clinical workflow. Approximately 40% of patients experience regular breathing; an increase from 40% to 60% using the AV biofeedback system would be clinically worthwhile. A sample size of 50 patients receiving the AV biofeedback system will have at least 80% power with 95% confidence to rule out a regular rate of 40% in favour of a 60% rate; with 25 patients receiving standard care (control group). The study design will be a randomised phase II trial stratified by treatment intent and oncology site. Results: The AVIATOR NEAF has been approved. Site-specific agreements are being finalised with the radiation oncology sites. On-site AV biofeedback training has commenced with several dry-runs being completed with the participation of hospital staff. A brief information video has been made with the intent of clearly describing to patients the role of AV biofeedback.

Background and Aim: Von Hippel Lindau (VHL) disease is an autosomal dominant, inherited, neurocutaneous dysplasia. The intracranial, spinal and abdominal manifestations of VHL and their imaging appearance at MRI are well documented in the literature. While there are recognised clinical, pathological and multi-modality imaging components to VHL screening, there are no established protocols for MRI screening in the literature. The aim of this study is to present a standard protocol for MRI screening, including the rationale for particular sequences and case examples from several institutions. Method and Results: A PubMed search was performed to retrieve studies relating to VHL imaging manifestations, MRI features, and screening methods and protocols. An existing MRI screening protocol, developed in collaboration between the Medical Imaging Department of Prince of Wales Hospital and the Prince of Wales and St. George Hereditary Cancer Clinic, was examined against the literature. Case examples from these centres were collected and their outcomes relating to screening, examined. In addition, the benefits and limitations of MRI screening were explored and compared with other imaging modalities, in particular MDCT. Conclusion: The MRI features of the manifestations of VHL are well established and MRI is a sensitive and specific screening tool. Compared to MDCT, MRI has the additional benefit of reducing the radiation burden on a population for whom 1–2 years screening of the central and autonomic nervous systems and retroperitoneal viscera is required from the time of diagnosis. The MRI screening protocol presented in this study is offered for consideration by clinicians and medical imaging specialists as an alternative to existing screening methods.

Fig. 1. Schematic of the AV biofeedback system in both imaging and treatment rooms. Real-time breathing motion in the form of a marker moving up and down with a personalised guiding-wave.

Conclusions: This clinical trial is the culmination of ten years of research into respiratory guidance technology and will be the largest and first randomised multicentre AV biofeedback trial to date.


300 Differentiating renal masses as cystic or solid using dual energy computed tomography (DECT) scanning D Rai, J Pratnap and J Coucher

Scientific Exhibits Perimesencephalic subarachnoid haemorrhage M Ratnayake Royal Perth Hospital, Western Australia, Australia

Princess Alexandra Hospital, Department of Radiology, Queensland, Australia Aim: The incidental detection rate of renal cysts has been reported to be as high as 48–66%.1 Homogeneous solid renal masses are more difficult to differentiate from renal cysts compared to heterogeneous solid masses on traditional CT.2, 3 DECT scanning enables the differentiation of cystic and solid masses using iodinated maps due to increased iodine uptake in solid masses.4 Despite the high incidental renal cyst detection rate, patients are not routinely scanned using DECT with iodine maps at the Princess Alexandra Hospital, Queensland. The aim of this pilot study was to assess the benefit of DECT in differentiating cystic from solid renal masses. Method: In this pilot study, patients requiring CT-abdomen at the Princess Alexandra Hospital during March 2014 were scanned using a 140 kV/100 kV DECT scanner. Iodine overlay maps were generated to differentiate incidental renal cysts from solid renal masses. Results: Ten patients (n = 10) were scanned using DECT during March 2013. A consultant radiologist reported on the imaging. Incidental Renal masses were detected in 30% (n = 3) of patients. All three patients with renal masses had cystic masses defined on both plain CT and DECT with iodine overlay maps. There were no patients with solid renal masses. Conclusion: Three patients were diagnosed with incidental cystic renal masses. There were no solid renal masses diagnosed on DECT in our pilot study. A larger sample size would provide a better indication for the role of DECT in differentiating homogenous solid renal masses from incidental renal cysts. As this is an ongoing pilot study, a larger data set will be presented at the upcoming ‘Combined Scientific Meeting’. References 1. Volpe A, Panzarella T, Rendon RA, Haider MA, Kondylis FI, Jewett MA. The natural history of incidentally detected small renal masses. Cancer 2004; 1004: 738–45. 2. Suh M, Coakley FV, Qayyum A et al. Distinction of renal cell carcinomas from high-attenuation renal cysts at portal venous phase contrast enhanced CT. Radiology 2003; 228: 330. 3. Jonisch AI, Rubinowitz AN, Mutalik PG et al. Can high-attenuation renal cysts be differentiated from renal cell carcinoma at unenhanced CT? Radiology 2007; 243: 445. 4. Neville AM, Gupta RT, Miller CM et al. Detection of renal lesion enhancement with dual-energy multidetector CT. Radiology 2011; 259: 173.

Aim/Learning Objectives: To recognise the distinct clinical entity known as the Perimesencephalic Haemorrhage. Background: Recognising the clinically distinct neuroradiological finding of Perimesencephalic (PM) Haemorrhage is of paramount importance given that in the majority of cases the cause is nonaneurysmal in nature and additionally that prognostically clinical outcomes are excellent (1). First described in 1985 (2) Perimesencephalic Haemorrhage is part of a diverse group of conditions known to cause nonaneurysmal SAH (NASAH). For the majority of PM-NASAH the etiology is not well defined and various hypothesis are present ranging from rupture of perforating arteries (3) to Basilar artery wall haematoma (4). The clinical presentation of those with PM-NASAH generally is less severe when compared to that of aneurysmal SAH and will account for 10 percent of patients with subarachnoid haemorrhage. Method/Imaging Findings: CT is the initial modality of choice to investigate SAH. In relation to Perimesencephalic Haemorrhage a distinct pattern identities a patient as having PM-NASAH. Generally speaking blood will be localised to the perimesencephalic cisterns anterior to the brainstem, blood may also traverse into basal sylvian fissures or the ambient cisterns of the sylvian fissures. Patients with perimesencephalic SAH patterning on CT should proceed to angiography of some sort with the generally accepted techniques being CT Angiography (CTA), Magnetic Resonance Angiography (MRA) and Digital Subtraction Angiography (DSA). Images to follow. Conclusion: Given the prognostic differences between aneurysmal and nonaneurysmal SAH it is crucial to establish the diagnosis of Perimesencephalic Haemorrhage. Following on from this intracranial aneurysm must always be as conclusively excluded as possible with a variety of angiographic techniques available. References 1. Velthuis BK, Rinkel GJ, Ramos LM, Witkamp TD, van Leeuwen MS. Perimesencephalic hemorrhage. Exclusion of vertebrobasilar aneurysms with CT angiography. Stroke; A Journal of Cerebral Circulation 1999 May; 30(5): 1103–9. PubMed PMID: 10229751. Epub 1999/05/07. eng. 2. van Gijn J, van Dongen KJ, Vermeulen M, Hijdra A. Perimesencephalic hemorrhage: a nonaneurysmal and benign form of subarachnoid hemorrhage. Neurology 1985 Apr; 35(4): 493–7. PubMed PMID: 3982634. Epub 1985/04/01. eng. 3. Alexander MS, Dias PS, Uttley D. Spontaneous subarachnoid hemorrhage and negative cerebral panangiography. Review of 140 cases. Journal of Neurosurgery 1986 Apr; 64(4): 537–42. PubMed PMID: 3950737. Epub 1986/04/01. eng. 4. Schievink WI, Wijdicks EF. Origin of pretruncal nonaneurysmal subarachnoid hemorrhage: ruptured vein, perforating artery, or intramural hematoma? Mayo Clinic Proceedings 2000 Nov; 75(11): 1169–73. PubMed PMID: 11075747. Epub 2000/11/15. eng.


Scientific Exhibits

301

Institutional imaging guidelines for the management of small bowel Crohn’s disease S Raza and J Rowe

Retrospective analysis of CT guided bone biopsy outcomes using a battery-powered intraosseous device A Reeve, B Pearch, M Gandhi and J Coucher

Dalhousie University, Halifax, Canada

Department of Medical Imaging, Princess Alexandra Hospital, Queensland, Australia

Aim: Our objective was to develop evidence based, institution specific guidelines, for the management of small bowel Crohn’s disease. Method: We reviewed the available literature and guidelines available for imaging of Crohn’s disease. We compared those to our institutional practices and devised our guidelines based on the available resources. Imaging Findings or Procedure Details: There is no consensus regarding the imaging of inflammatory bowel disease. The imaging modality chosen depends on the clinical presentation. The choice is impacted by the resources available and expertise of performing physicians. The effect of radiation is also a major consideration due to frequent imaging requirements. We came up with the imaging guidelines for small bowel evaluation in Crohn’s disease in different clinical situations. CT enterography has the advantage of being non invasive and rapid and found to have similar diagnostic accuracy as CT enteroclysis. We favour its use for initial evaluation of disease. It can also be used for the evaluation of acute flare ups and complications. Magnetic resonance enterography (MRE) enjoys the benefit of being free of ionising radiation and delivers similar information regarding disease activity and complications. We recommend the use of MRE particularly in younger population. The utility for other modalities is also discussed. Conclusion: It is essential to standardise institutional guidelines for the imaging of Crohn’s disease so that the disease could be diagnosed reliably and to reduce the number of imaging tests with low diagnostic yield.

Aim: To compare a novel battery-powered intraosseous device with the current gold standard manual technique used to perform core bone biopsy under CT guidance. Method: A retrospective analysis of outcomes in 12 patients from the Princess Alexandra Hospital (Brisbane, Qld, Australia) in whom the OnControl bone marrow biopsy system (OBM, Vidacare, Shavano Park, TX, USA) was used was compared to an age- and gendermatched sample of patients who underwent a manual procedure (Cook trephine). Outcome measures compared were intervention time (min), needle localisation (successful/unsuccessful), interpretability of the histologic sample (evaluable/non-evaluable), radiation exposure (mean DLP) and complication rate (SIR B or higher). Results: No significant differences between outcome measures were found when biopsies obtained using the powered drill were compared to those performed with the current gold standard manual technique (p > 0.05 for all measures). These Australian hospital cohort data corroborate results recently published internationally (Schnapauff, 2013). Table 1. Outcome measures Field

Mean intervention time Mean total DLP Complication rate Needle localisation Histologic interpretability

Units

min:s mGy·cm +/− SD % % successful % evaluable

Powered drill

Cook trephine

17:42 17:31 555 +/− 452 573 +/− 361 0 0 100 100 100 100

Conclusion: Minimal data have been hitherto published on batterypowered intraosseous devices for core bone biopsy. Preliminary findings suggest these may be as effective as the current gold standard manual technique. Reference Schnapauff D, Marnitz T et al. CT guided bone biopsy using a battery powered intraosseous device. Cardiovascular and Interventional Radiology 2013 Oct; 36(5): 1405–10.


302

Scientific Exhibits

Measuring cell density in prostate cancer imaging as an input for radiotherapy treatment planning H Reynolds,1,2 S Williams,3,4 A Zhang,5,6 C Ong,5,6

MRI guided breast intervention, imaging and histological correlation S Rezai and C Grobbelaar

D Rawlinson,5,6 R Chakravorty,5,6 C Mitchell7 and

QLD XRAY, Queensland, Australia

A Haworth1,2 1

Dept Physical Sciences, Peter MacCallum Cancer Centre,

2

Sir Peter MacCallum Dept Oncology, University of

Melbourne, 3Dept of Pathology, University of Melbourne, 4

Division of Radiation Oncology and Cancer Imaging, Peter

MacCallum Cancer Centre, 5NICTA, Victorian Research Laboratory, Melbourne, 6Electrical and Electronic Engineering, University of Melbourne, 7Dept Pathology, Peter MacCallum Cancer Centre, Victoria, Australia Aim: The purpose of this study was to compute cell density in high resolution prostate histopathology images for registration with multiparametric MRI (mpMRI) to parameterise our prostate radiobiological model (1). With this model, future patients will have dose distributions tailored to tumour location and tumour characteristics, including cell density, shown on in-vivo mpMRI. Method: Histopathology data were obtained from five patients treated by radical prostatectomy at the Peter MacCallum Cancer Centre, Melbourne. Specimens were processed using the standard clinical protocol, with whole-mount microscopic slices cut, stained with haemotoxylin-eosin (H&E) and scanned at 20x magnification. A tilebased method was applied to count cell nuclei using colour deconvolution and a radial symmetry transform (2). Results: Cell density maps were computed for 22 slides, containing tumours with Gleason Scores from 6 to 9. Kolmogorov Smirnov tests confirmed cell density in tumour was significantly different than in benign regions of tissue, using ground truth annotations from an expert pathologist (p < 0.05). Preliminary analysis indicates cell density correlates with decreased signal intensity on T2-weighted and ADC maps from diffusion weighted MRI. Conclusion: We have successfully developed an automatic method to measure cell density in histopathology images. Future studies will demonstrate a correlation of cell density with co-registered mpMRI to provide parameters for our radiobiological model.

Aim: This retrospective study was performed to review MRI guided breast interventions performed in our centre, to correlate the imaging and histopathology results and to detect the positive predictive value. Method: From January 2010 to April 2012, 61 MRI guided breast intervention were performed on 57 women. Retrospective review of these cases was performed to identify patient age, indication for MRI examination, lesion characterisation including size, morphology, enhancement and histological finding. Results: The indications for the initial contrast enhanced breast MRI examination were categorised as screening of high-risk patients, metastatic disease to axillary lymph node with no known primary and in problem solving cases where conventional breast imaging was noncontributory. There were 20 (28.2%) malignant lesions including 7 mass and 13 non-mass lesions. There were 8 (11.3%) high-risk lesions for which excision was required. The sensitivity of MRI in detecting malignant lesions was 88.1% and the specificity was 46%. The low specificity was attributed to known high false positive rate of breast MRI and selected study population with the majority being high-risk patients. For mass lesions, morphological features such as irregular shape and spiculated margin as well as heterogeneous enhancement had higher positive predictive value (0.75) for malignancy. For nonmass lesions, the lesion descriptors were found less specific with relative low positive predictive value for morphology (0.21). The clumped enhancement and rapid wash out were the strongest predictors of malignancy (positive predictive value of 0.41 and 0.75, respectively). Conclusion: Breast MRI is a valuable tool in detection and management planning of breast cancer particularly in high-risk population, cases with axillary lymph node metastasis with unknown primary and in problem solving group. MRI can also be used for histological assessment of suspicious lesions when other imaging modalities are not helpful.

References 1. Haworth A, Williams S, Reynolds H et al. Validation of a radiobiological model for low-dose-rate prostate boost focal therapy treatment planning. Brachytherapy 2013 Jul 18; 12(6): 628–36. Elsevier Inc. 2. Reynolds HM, Williams S, Zhang AM et al. Cell density in prostate histopathology images as a measure of tumour distribution. SPIE Med Imaging Conference. San Diego; 2014.


Scientific Exhibits Pre-treatment information needs and preferences of radiotherapy patients P Ripoli,1,2 C Goodwin,2 A Myers,2 C Kirpichnikov,2

303

S Everitt,2,3,4 L Sparks2 and R Oates2,5

Two methods of calculating alpha angle in computed tomography assessment of femoroacetabular impingement D Robinson,1 S Lee,1 P Marks2 and M Schneider3

1

1

Healthcare Imaging Services, 2Imaging Associates,

3

Monash University, Victoria, Australia

Sunshine Hospital Radiation Therapy Centre, St Albans, 2

Victoria, Australia, Radiation Therapy, Peter MacCallum Cancer Centre, East Melbourne, Victoria, Australia, 3

Department of Medical Imaging and Radiation Sciences,

Faculty of Medicine, Nursing and Health Sciences, Monash University, Clayton, Victoria, Australia, 4Sir Peter MacCallum Department of Oncology, University of Melbourne, Victoria, Australia, 5Bendigo Radiotherapy Centre, Bendigo, Victoria, Australia Aim: When patients commence radiotherapy (RT) it is vital they have a good understanding of their treatment and access to relevant information. This project aimed to determine whether the information given to patients prior to commencing RT at Peter MacCallum Cancer Centre in East Melbourne and Sunshine Hopsital Radiation Therapy Centre is appropriate and sufficient. We aimed to conclude how patients would prefer to be provided with this information and plan to utilise the results to further develop our information processes. Method: Following ethics approval, 100 patients commencing RT were invited to complete a paper-based survey. Exclusion criteria included patients who did not speak English, were under the age of 18, and who had completed previous treatment. The survey comprised 15 multiple choice questions. 3 questions also allowed the patient to elaborate with a written response. Results: Between Oct 2013 and Jan 2014, 85 patients completed the survey. 40(47%) patients reported they had a very good understanding of RT prior to commencing treatment, and 27 (31.7%) of patients reported a good understanding. 48 (53%) patients strongly agreed that their information needs were met by the RT in the pre-treatment information session, with 44 of the 48 patients stating they felt prepared for their treatment. A further 38 (44.7%) agreed that their information needs were fulfilled by the RT. 19 (22%) patients felt they would benefit from further written information, 20 (23.5%) the use of multimedia in their pre-treatment information session, and 19 (22%) patients would welcome the introduction of a group information session and department tour. Conclusion: Almost every patient reported they felt prepared for RT and were satisfied with the information provided. While this reflects positively on the current information processes there is potential for further development, including the introduction of multimedia packages.

Aim: Two different methods for calculating femoral head-neck alpha angles have been widely described, but to date have not been compared. The alpha angle calculated using a femoral axis line parallel to the anterior femoral neck is more clinically relevant than a measurement taken using the centre of the narrowest point of the neck. We sought to compare the two published methods using axial images of patients having a three-dimensional CT (3DCT) hip scanning procedure at our institution. Method: Alpha angles were calculated following the departmental protocol using the method for 3D CT first described by Beaule et al (2005) [1]. Raw axial images were then analysed again using the original method for calculating the femoral head-neck alpha angle first described by Notzli et al (2002) [2]. Measurements calculated using the two different methods were analysed using the non-parametric Wilcoxon matched pairs signed rank test. Results: There were 34 hips for analysis. Ages ranged from 19 years to 74 years (average 38.9 years (±14.5) years). The mean alpha angle calculated using the method described by Beaule was 61.59 (±14.3) degrees (range 37.7–90.9). The mean calculated alpha angle when the same hips were analysed using the method described by Notzli was 54.01 (±13.1) degrees (range 37.6–79.2). The mean difference between the two measurements was 7.6 degrees (95%CI 4.9–10.2) (p < 0.0001). Conclusion: There is a statistically significant difference in calculated alpha angle between the two different methods. Alpha angles reported as abnormal may result in unnecessary surgical intervention. We believe that the alpha angle should be calculated using a femoral neck baseline parallel to the anterior femoral neck. The threshold of normal for the alpha angle should be raised above 55 degrees. Radiology reports should consider factors other than alpha angles before reporting tests as positive for FAI.

References 1. Beaule PE et al. Three-dimensional computed tomography of the hip in the assessment of femoroacetabular impingement. J Orthop Res 2005; 23: 1286–92.


304

2. Notzli HP et al. The contour of the femoral head-neck junction as a predictor for the risk of anterior impingement. The Journal of Bone and Joint Surgery (BR) 2002; 84-B: 556–60.

Scientific Exhibits Improving dosimetry for synchrotron Microbeam Radiation Therapy P Fournier,1 I Cornelius,1,4 J Crosbie,2 P Berkvens,3 A Dipuglia,1 N Roberts,1 H Requardt,3 A Stevenson,4,5 C Hall,4 M Petasecca,1 A Rozenfeld,1 E Bräuer-Krisch3 and M Lerch1 1


Wollongong, New South Wales, Australia, 2University of Melbourne, Department of Obstetrics and Gynaecology Royal Women’s Hospital, Victoria, Australia, 3European Synchrotron Radiation Facility, Grenoble, France, 4Imaging and Medical Beam Line, Australian Synchrotron, Victoria, Australia, 5CSIRO Materials Science and Engineering, Clayton, Victoria, Australia Aim: Microbeam Radiation Therapy (MRT) is a promising cancer treatment modality currently under development at several synchrotron facilities around the world. MRT is based on the dose-volume effect that leads to non-cancerous tissue sparing while being toxic to tumour tissue by using spatially fractionated synchrotron generated X-ray beams(1). This study focuses on the efforts carried out in the improvement of the dosimetry in MRT. Method: Absolute dosimetry is performed with a small volume ionisation chamber (IC) under homogeneous beam conditions. Due to the high dose rate from the synchrotron X-ray source, a dedicated method is required in order to determine the ion recombination correction factor (Ks) to apply to the IC readings. This method is based on the linear relationship between Ks and the dose rate. For peak (in the microbeam) and valley (between the microbeams) dosimetry, the X-Tream quality assurance system that incorporates a silicon Single Strip Detector (SSD) has been developed to measure the peak to valley dose ratio (PVDR) in water equivalent phantoms in real-time(2). Measurements have been carried out at both the European Synchrotron Radiation Facility (ESRF) at the biomedical beamline (ID17) and at the Imaging and Medical Beam Line of the Australian Synchrotron. Results: By extrapolating the IC readings to the very low dose rates, one can determine the value for a 100% detection efficiency and thus Ks (FIG. 1). FIG. 2 shows the microbeam array obtained at the ESRF (vertical microbeams each 0.520 mm high and 50 μm wide) at 2 cm depth in a water phantom with the X-Tream system and SSD.


Scientific Exhibits

305 An efficient EPID-based method for linac collimator spoke shot test P Rowshanfarzad,1 M Sabet2 and M Ebert1,2 1

School of Physics, University of Western Australia,

2

Department of Radiation Oncology, Sir Charles Gairdner

Hospital, Western Australia, Australia

Fig. 1. Experimental determination of Ks.

Aim: The purpose of this study is to develop an automated EPIDbased technique for quick, easy, and accurate performance of jaw and MLC spoke shot tests. This method can replace current film-based techniques [1]. Method: Measurements were performed on a Varian linac. The spoke shot tests were carried out with X-jaw, Y-jaw and MLC-defined 0.5 x 18 cm2 fields with the EPID at 150 cm distance from the source. To determine the optimum number of spokes for accurate results, measurements were made with 3 to 10 spokes defined at equal steps over 180 degree collimator angles. An algorithm was developed to find the points of intersection of spokes on EPID images and seek the largest circle inscribed in all of the formed triangles. The work was performed at cardinal angles to investigate the gravity effect. Results: It was shown that having 6 spokes is required for optimum results. Therefore, collimator angles of 0, 30, 60, 90, 120 and 150 degrees were used. Results for jaw-defined and MLC-defined spokes, in addition to their reproducibility are shown in the table. All values are in mm.

X-Jaw Y-Jaw MLC

Fig. 2. ESRF MRT field measured using X-Tream.

Conclusion: The Ks correction factor can be determined thanks to a dedicated method which contributes to the improvement of the MRT reference dosimetry. The SSD showed its ability to perform qualitative measurement of the microbeam intensity profile and to estimate the PVDR.

Gantry 0

Gantry 90

Gantry 180

Gantry 270

Reproducibility

0.08 0.09 0.20

0.05 0.07 0.17

0.11 0.14 0.13

0.10 0.21 0.20

0.01 0.00 0.08

Conclusion: An accurate, user-friendly, reproducible and automated EPID-based method was developed for film-free assessment of the central axis beam variation due to collimator rotation. Using this method saves plenty of time and the program takes only 2.6 seconds to run. Reference 1. Depuydt T, Penne R, Verellen D et al. Computer-aided analysis of star shot films for high-accuracy radiation therapy treatment units. Phys Med Biol 2012; 57: 2997–3011.

References 1. Dilmanian FA, Button TM, Le Duc G et al. Response of rat intracranial 9L gliosarcoma to microbeam radiation therapy. Neuro Oncol [Internet] 2002 [cited 2013 Sep 4]; 26–38. Available from: http:// proceedings.spiedigitallibrary.org/data/Conferences/SPIEP/54705/ 38_1.pdf 2. Petasecca M, Cullen A, Fuduli I et al. X-Tream: a novel dosimetry system for Synchrotron Microbeam Radiation Therapy. J Instrum [Internet] 2012 Jul 31 [cited 2013 Sep 1]; 7(07): P07022–P07022. Available from: http://stacks.iop.org/1748-0221/7/i=07/a=P07022 ?key=crossref.8d1255d7745abc72cb917ba74e51af5f


306

Scientific Exhibits

An automated method for assessment of MLC leaf positioning accuracy for stereotactic radiotherapy M Sabet,1 P Rowshanfarzad,2 S Somangili1 and M Ebert1,2

Pre-operative assessment of the axillary lymph nodes in patients with breast cancer and literature review B Saffar, M Bennett, C Metcalf and F Burrows

1

Royal Perth Hospital, Western Australia, Australia

Department of Radiation Oncology, Sir Charles Gairdner

Hospital, 2School of Physics, University of Western Australia, Western Australia, Australia Aim: The aim of this study was to develop and assess an automated EPID-based technique to investigate the accuracy of leaf positioning for stereotactic radiotherapy treatments. Method: A Varian linac equipped with MillenniumTM 120-leaf MLC and an aS500 EPID was used for measurements. A 2-cm radius circle was formed by the MLC Shaper software. EPID images were acquired at cardinal gantry angles. To define the radiation centre and use it as reference for assessments, two MLC-defined 10 x 10 cm2 fields at 90 and 270 degree collimator angles were also imaged at each gantry angle [1]. An algorithm was developed to automatically determine the position of each individual leaf forming the circle relative to the reference (beam centre), and compare them with planned positions. Results for each leaf were automatically saved in a spreadsheet with the test date, and plotted on graphs. The method was evaluated by insertion of intentional errors in some leaves. The reproducibility of the method was tested on the same day and on different dates. Results: The average deviations detected for leaves forming the circle in left and right banks are given in the Table.

Left bank

Right bank

Gantry angle 0 90 180 270 0 90 180 270 (degrees) Average –0.95 –0.57 –0.79 –0.81 0.01 –0.13 0.05 0.11 offset (mm) 1SD (mm) 0.05 0.04 0.05 0.05 0.02 0.05 0.05 0.07 Average –0.78±0.15 0.08±0.07 offset (mm)

The method reproducibility was found to be 0.01 mm. The intentional errors were detected with an accuracy of 0.03 mm. Conclusion: A simple and accurate automated EPID-based method was developed for quick assessment of leaf positioning accuracy for stereotactic treatments. This method is valid for other test shapes provided that it is formed with the central leaves. It can be a useful tool to determine if MLC calibration is required. Reference 1. Clews L, Greer PB. An EPID based method for efficient and precise asymmetric jaw alignment quality assurance. Med Phys 2009; 36(12): 5488–96.

Aim: In 2010, a protocol was introduced at Royal Perth Hospital. Patients with a Tabar 4 or 5 lesion had the axilla evaluated. A 3 mm cortical thickness was used as threshold to prompt fine needle aspiration biopsy (FNAB) of the lymph node (LN.) The aim of our audit is to evaluate the accuracy of this protocol in our population, and to compare it with published data. We were interested to see whether there is any subgroup of women at low risk for axillary nodal involvement. Methods: 893 patients were diagnosed with breast cancer between 2010 and 2012. 100 women had axillary LN with cortical thickness of more than 3 mm and underwent US guided FNAB. Data were collected for the index breast lesion, as well as cortical thickness of the lymph node. Results: 57 patients out of 100 had malignant FNA. The average cortical thickness was 6.9 mm. High-grade breast cancers were identified in 30 patients (52%). The average size of the breast lesions was 37.3 mm. 33 patients had benign cytology. Average cortical thickness in this group was 3.9 mm. 21% had high-grade cancers. Average size of the breast lesions was 22.5 mm. 42% of patients were screen detected compared to 29.8% in the first group. 10 patients had 10 mm or less breast cancer, axillary LN metastases demonstrated in 40%. 6 patients had DCIS, cortical thickness was 3.3–5 mm but none of the LN showed metastases. Hiroyuki et al concluded the cortical thickening had high sensitivity (79%) in predicting metastases (1). Lernevall considered eccentric enlargement is a strong indicator of malignancy (2). Conclusion: The likelihood of axillary LN metastases increases with the increase cortical thickness, this concurs with the literatures. The size of the breast cancer is not a good predictor for axillary LN involvement. In the low risk subgroups (DCIS), preoperative assessment of axilla did not alter management. References 1. Hiroyuki A et al. Axillary lymph nodes suspicious for breast cancer metastasis: sampling with US- guided 14-gauge core-needle biopsy – clinical experience in 100 patients. Radiology 2009 January; 250(No 1): 41–9. 2. Lernevall A. Imaging of axillary lymph nodes. Acta Oncologica 2000 May 10; 39(No 3): 277–81.


Scientific Exhibits Coronary artery dosimetry for adjuvant left-sided breast radiotherapy: changes in reported dosimetry when the left anterior descending artery (LAD) contour is shifted from its true position S Sampaio and P Graham St George Hospital Radiation Oncology Department, New South Wales, Australia Aim: As coronary arteries can be difficult to contour, errors in can contouring occur.1 By simulating potential shifts in coronary artery contours that can arise through errors in contouring, we aimed to determine to what extent the LAD can be misplaced (in medial, lateral, superior and inferior directions) before one sees significant change in reported dose. Method: 10 patients from the STARS study who had received leftsided breast or chest wall radiotherapy were selected.2 Identical vessel contours were created that were 5, 10 and 15 mm medial and lateral to the existing LAD contour. Contours simulating superior and inferior LAD shifts in 6, 12 and 18 mm increments were created. Comparisons in reported dose were made between original and simulated contour positions. Results: Shifts in the whole LAD ≤10 mm resulted in differences in reported mean dose 5 fractions were excluded. Treatment related toxicities, survival, and progression outcomes were analysed and compared for patients treated for primary versus metastatic disease. A projection for caseload in 2014 was estimated based on SABR program accrual rates. Results: From Feb 2010 until September 2013, 100 consecutive patients were treated, with 59% enrolled into prospective clinical trials. Preliminary data from 90 patients and 110 treated targets were included. The median(range) F/U was 11 months (range 1–47 months). Target sites were lung in 70(64%), kidney in 20(18%), spine/bone in 11(10%), and adrenal in 5(5%) of treatments. The commonest histology was non-small cell lung cancer (n = 31, 34%), followed by renal cell carcinoma (n = 25, 28%). Single fraction SABR was used in 91(83%) of cases, with 3 fractions in 12(11%) and 4 fractions in 7(6%) of cases. No grade 3+ toxicities were recorded. The incidence of grade 1–2 toxicities was 42%(95%CI [32–52]), with no difference between single and multi-fraction approaches (p = 0.33). The 1 and 2 year actuarial overall survival estimates were 95% (95%CIs [90–100%]) and 87% (95%CIs [76–100%]), respectively (Figure 1), with no difference detected for primary versus metastatic disease (p = 0.09). The 1 and 2 year actuarial local control estimates were 89% (95%CIs [82– 98%]) and 86% (95%CIs [76–97%]), respectively. Based on caseload trends, by September 2014 a linear (low) projection of total cases is 180, whilst a quadratic (high) projection is 231, Figure 2.

Fig. 2. Patient caseload and projections, using linear fit (low estimate) and quadratic fit (high estimate) projections.

Conclusion: We describe promising survival and local control outcomes in patients treated within a predominantly single fraction SABR program founded on prospective clinical trials. The utilisation of SABR is rapidly expanding in our institution.

Fig. 1. Kaplan–Meier curve for overall survival (all patients). Dashed lines represent the 95% confidence interval.


318 Impact of stereotactic ablative body radiotherapy on renal function after treatment of primary renal cell carcinoma S Siva, D Pham, P Jackson, T Kron, A Lim, S Grills,

Scientific Exhibits A phantom for ultrasound guided low dose rate brachytherapy seed implant training R Franich,1 S Keehan,1 C Beaufort,2 A Haworth1,3 and R Smith1,2

N Brooks, J Goad, D Moon, S Gill, M Shaw, K Tai and

1

RMIT University, School of Applied Sciences, Melbourne,

F Foroudi

2

William Buckland Radiotherapy Centre, The Alfred Hospital,

Peter MacCallum Cancer Centre, Victoria, Australia

Melbourne, 3Dept Physical Sciences, Peter MacCallum Cancer Centre, Melbourne, Victoria, Australia

Aim: Stereotactic ablative body radiotherapy (SABR) is an emerging non-invasive treatment modality for inoperable primary renal cell carcinoma (RCC)1. The purpose of this study is to assess the impact of SABR on renal function using nuclear medicine scintigraphy and serum biochemistry. Method: As part of a prospective ethics board approved clinical trial, patients with primary RCC received single fraction SABR of 26 Gy (tumours 5 cm). Prior to treatment, 14 days post treatment, and 70 days post-therapy, glomerular filtration rate (GFR) was measured by 51Cr-EDTA clearance and renal perfusion was recorded by 99mTc-DMSA SPECT/CT. Serum creatinine (Cr) was measured 3 monthly post-SABR. Results: From July 2012 to November 2013, 22 patients received SABR on trial, with 11 receiving single fraction and 11 receiving multifraction SABR. The mean (range) tumour size was 49 mm (20– 75 mm). In 9/22 patients, referral was precipitated by the likely need for post-surgery dialysis. At a mean (range) follow-up of 10.2 months (2.7–18.0 months), there was no statistically significant variation in the median 51Cr-EDTA-GFR at baseline (49 mls/min), post therapy at 14 days (50 mls/min) or 70 days (49 mls/min), ANOVA F = 0.61, p = 0.52. Mean serum Cr declined from 131 μmol/l from pre-treatment to 153 μmol/l at last recorded follow-up (paired t-test, p = 0.013). The change from pre-treatment serum Cr to last recorded Cr was not correlated to time, Pearson r2 = 0.146, p = 0.089. No patient has required dialysis to date, nor medical intervention for renal dysfunction. Conclusion: In this patient cohort, despite having pre-treatment kidney dysfunction, SABR does not cause early post-treatment renal dysfunction. Mild deterioration of kidney function is observed in the medium-term without the need for either significant medical interventions or dialysis.

Aim: To design a simple cost effective phantom for the purpose of practical training in low dose rate (LDR) brachytherapy seed implantation under ultrasound guidance. Method: Due to the high cost of commercial products, a simple, low cost solution was proposed, consisting of a transparent plastic container of gelatine (7% wt.). The phantom was penetrable by a LDR brachytherapy needle and to facilitate seed deposition using the usual manual technique of retracting the hollow needle while displacing the seeds with the stillette. During the gel setting phase, a cylindrical void was created in the gel to accommodate a trans-rectal ultrasound (TRUS) probe to guide needle insertion and confirmation of seed placement. A target region was created by filling a second void with a lower concentration gel mixture (3.5% wt.) to provide visible contrast under ultrasound. Results: The phantom is shown in figure 1 with the TRUS inserted in the cavity and a brachytherapy needle being inserted through the template. The transparent phantom allowed other observers to see the seed deposition occurring. The target region is visible in the US image (figure 2).

Fig. 1. Phantom, TRUS and brachytherapy needle.

Fig. 1. Tc99 DMSA SPECT/CT demonstrating mid-pole RCC with surrounding cortical perfusion. Reference 1. Siva S, Pham D, Gill S et al. A systematic review of stereotactic radiotherapy ablation for primary renal cell carcinoma. BJU Int 2012; 110: E737–43.


Scientific Exhibits

319 Demonstration of the quality assurance benefits of a new in vivo source position verification system for high dose-rate prostate brachytherapy J Millar,1,2 R Smith,1,2 B Matheson,1 B Hindson,1 A Haworth,2,3 M Taylor,1,2,3 L McDermott2 and R Franich1,2 1

William Buckland Radiation Oncology, Alfred Health,

Melbourne, Australia, 2School of Applied Sciences and Health Innovations Research Institute, RMIT University, Melbourne, 3Physical Sciences, Peter MacCallum Cancer Centre, East Melbourne, Victoria, Australia

Fig. 2. US guidance showing visible low density target region.

Conclusion: The phantom design met the requirements of the teaching activity and was easy to produce at low cost.

Aim: HDR brachytherapy techniques deliver high doses very quickly, typically in hypo-fractionated schedules. Potential mistakes could cause serious adverse clinical effects that cannot be remediated in further fractions. ICRP–97 reviewed brachytherapy accidents. They identified human error as the prime cause in the more than 500 reported accidents. In external beam radiotherapy, independent dose recording and verification systems are standard. There is no independent routine treatment delivery verification system to identify potential errors and ensure patient safety in HDR brachytherapy treatment. We report a demonstration of how a novel position-sensitive sourcetracking system based on a flat-panel imager for prostate HDR brachytherapy could detect and prevent or ameliorate many potential errors in HDR treatment. Method: We mounted a flat-panel imaging device within a theatre couch, to study four prostate cancer patients with implanted gold markers. We acquired an image of three x-ray dwell position markers in the implanted catheters in each patient, and then delivered the HDR source treatment dwells, acquiring and processing images to determine the source positions. These positions measured by the imaging device were compared to the treatment plan to verify planned treatment delivery. Results: The total setup, treatment, and disconnection time was not materially increased. We captured images of the source position in patients for both fractions. The measured dwell positions and total dwell time in each measured catheter allowed the rapid identification of potential errors. Conclusion: Our method allows immediate in vivo visualisation of HDR dwell positions and, in principle, the ability to measure and verify dose and dose distribution from an HDR brachytherapy implant. This evaluation, during a treatment, of what the patient is actually receiving has the potential for detecting the vast majority of potential treatment errors, and verify that the patient is actually receiving the treatment we planned. Reference ICRP. Prevention of high-dose rate brachytherapy accidents ICRP 97. Annals of the ICRP 2009; 27: 1–54.


320 A comparison of evaluation methods for comparing contours of swallowing organs in the head and neck S Smith, L Gholamrezaei, J Benson, L McLean, G Whittington and K Foo Chris O’Brien Lifehouse, New South Wales, Australia

Scientific Exhibits The dosimetric benefits of Deep Inspiration Breath-Hold (DIBH) in left breast radiation therapy: A systematic review L Smyth,1 Y Aarons,1 J Wasiak2 and K Knight2 1

Epworth Radiation Oncology, 2Monash University, Victoria,

Australia Aim: There are several methods traditionally used for contour comparison. Our aim is to evaluate methods of comparison of organs used for swallowing in the head and neck region in a clinical setting and determine the difference between comparing contours to clinically significant PRVs and more conventional methods of contour comparison. Method: A retrospective study comprising five patients who received radical radiation treatment to the head and neck region was investigated by six study participants; two Radiation Oncology Specialists and four Radiation Therapists. Each of the six participants used an anatomical atlas to contoure nine swallowing organs in the head and neck. A gold standard was established as the structures outlined by one Radiation Oncologist and was qualitatively deemed acceptable by the second Radiation Oncologist. The structures created by the five other observers were compared using absolute volume, conformity index and percentage of volume encompassed by the PRV gold standard (ie 3 mm expansion). Results: The average conformity index per structure across the 5 patients revealed a range from 0.62 (cricopharyngeal muscle) to 0.92 (cervical oesophagus). When analysing the absolute volume of structures in comparison to the relative gold standard the range was 30.3% (middle pharyngeal constrictor muscle) to 172.7% (cervical oesophagus). Assessment using the PRV method indicated at least 95% of the volume for each structure was encompassed by the corresponding PRV. Qualitative assessment of the PRVs and structures also suggested clinically acceptable volumes. Conclusion: The nature of the organs in the head and neck outlined in this study highlights the restrictive nature of conventional methods of contour comparison. The PRV method of comparison did not find the same discordance as was evident when using the conventional methods. The re-entrant shape, size and location of some of these structures necessitates the development of more novel measures.

Aim: A review of current literature was undertaken to estimate the reduction of late radiation-induced cardiac mortality and morbidity when employing deep inspiration breath-hold (DIBH) for left breast cancer patients undergoing radiotherapy. Stability and reproducibility of employing DIBH techniques in a clinical setting was also examined. Method: The PubMed database was searched for studies reporting on DIBH using the key-terms ‘breath hold’, ‘breathing control’, gating, breast, and ‘radiation therapy’. Studies with at least 10 patients and involving the use of DIBH for the tangential irradiation of the left-breast or left chest-wall, with or without treating the axillary, supra-clavicular, or internal mammary chain lymph nodes were considered for inclusion in this review. Results: Nine dosimetric studies were reviewed in order to analyse the benefits of DIBH during left breast irradiation. Based on these studies, DIBH reduces the mean heart dose by up to 3.4 Gy when compared to a free breathing approach. According to current estimates of the excess cardiac toxicity associated with radiation therapy1, this is equivalent to 13.6% reduction in the projected increase in heart disease risk and a 25.2% reduction in the projected increase in the rate of major coronary events. Four studies assessed the stability and reproducibility of DIBH, reporting modest inter-fraction and intrafraction variations in patient position regardless of the imaging verification and monitoring protocol used. Conclusion: DIBH is a reproducible and stable technique for left breast irradiation that shows significant promise in reducing the late cardiac toxicities associated with radiation therapy. Future clinical trials with extended follow-up periods are required to confirm the estimated longterm cardiac sparing benefits associated with employing DIBH for left breast irradiation, as well as to determine the most appropriate imaging protocol to confer optimal treatment stability and reproducibility. Reference 1. Darby SC, Ewertz M, McGale P et al. Risk of ischemic heart disease in women after radiotherapy for breast cancer. N Engl J Med 2013 Mar; 368(11): 987–98.


Scientific Exhibits

321

Comparison of the use of a robotic needle positioning system to freehand technique in CT guided facet joint injections – illustrative cases T So, H Kavnoudias, N Tran, R Thmoas and K Thomson

A case report: Venous infarction of the spleen. A rare and unexpected sequelae of Portal vein thrombosis. An incidental finding and treatment dilemma A Sokolowsky1 and B Tan2

Alfred Hospital, Victoria, Australia

1

John Hunter Hospital, 2Armidale Hospital, New South

Wales, Australia Aim: Medical robotic positioning systems have the potential to revolutionalise image guided interventional procedures for both the clinician and patient, by potentially improving accuracy of needle placement, and consequently reducing the number of attempts required to complete a procedure. A key challenge in image guided minimally invasive procedures, as opposed to open surgical procedures, is the ability to access a specified point on an organ or tissue accurately, and the accuracy of needle placement is critical especially when accessing small locations or those located near other critical organs or structures. Lesser attempts are clinically beneficial and decreases risk to the patient and the time taken for the procedure to be completed. Radiation exposure is also dramatically reduced in proportion to the number of attempts, as the need for repeated intraprocedure verification scans are reduced. The Alfred Hospital has recently installed a Robotic Positioning System for use in interventional procedures such as facet joint injections, fine needle aspiration, and tumour ablation. Method: To date, no randomised trial has examined the use of the Robotic Positioning System in comparison to conventional freehand methods for CT guided interventional procedures. We present our preliminary work in use of the Robotic Positioning System in facet injections through select illustrative cases. Outcome/comparison measures include the following: 1. Time to Needle Placement • Time taken for needle placement, defined as the time from commencement of initial preliminary CT scan to time of accurate needle placement 2. Accuracy of Needle Placement • The distance between needle tip and target location on first needle placement attempt, as measured in millimetres on the CT workstation, and • The total number of check scans/passes required to successfully complete the procedure. 3. Procedural Radiation Dose • Total dose delivered to the patient measured in mSv, recorded at the end of the procedure. 4. Procedure Related Complications 5. Patient Satisfaction Results: Illustrative cases are presented. Conclusion: Early work with the Robotic Positioning System in facet joint injections has been promising. It has the potential advantage to deliver accurate needle placement, reduce the number of attempts and need for manual manipulation, and consequently reduce associated patient discomfort.

We present a case of a 75-year-old female who presented to a rural emergency department following a four day history of left upper quadrant abdominal pain. There was no history of recent trauma, only a background of diverticulosis and bronchiectasis. Computed tomography (CT) initially showed multiple hypodense wedge shaped splenic lesions consistent with a mixed age splenic infarct and a peri-splenic collection. There was no evidence of splenic arterial disease or aneurysm. A thrombus within the splenic vein was incidentally seen. The patient was extensively investigated for underlying haematological conditions, collagen vascular disease, occult malignancy and infective endocarditis. None could be found. A diagnosis of venous infarction of the spleen was therefore made, an exceedingly rare, but not unheard of entity. The patient was treated with therapeutic anticoagulation, but subsequently had a turbulent clinical course, necessitating multiple admissions and further radiological investigations. The patient is currently on ongoing outpatient management.


322 RT led treatment reviews: where to from here? M Newton,1 J Cox2,3 A Davies,1 M Rinks1 and J Atyeo2

Scientific Exhibits

of Sydney, 3Northern Sydney Cancer Centre, New South

The right inferior pulmonary vein pericardial recess: tumour mimicker and potential surrogate marker for cardiorespiratory disease J Soon and A Gupta

Wales, Australia

Fremantle Hospital, Western Australia, Australia

Aim: The Shoalhaven & Illawarra Cancer Care Centres have recently undertaken the TORToiSe project in conjunction with the North Sydney Cancer Centre. The aim of TORToiSe is to compare radiation therapist (RT) and radiation oncologist (RO) grading of breast cancer treatment toxicities. The aim of this presentation is to give an overview of local results and discuss out experiences and observations. Method: A selected group of RTs and a RO assessed patients undergoing treatment for breast cancer at selected intervals during treatment. Six toxicities were assessed following the RTOG guidelines; skin, fatigue, nausea, oesophagitis, pain and lymphoedema. Psychosocial factors were assessed using a self-designed scale. All assessment results were recorded in Mosaiq (Impac Medical Systems Inc, Sunnyvale, CA). Patients were interviewed to collect their experiences with the review process. Results: There were 224 separate toxicities assessed over twelve patients. The data are under analysis as part of the multicentre study and will be presented by Dr J. Cox. Locally our data suggest comparable assessments between the RO and RTs. Identified differences between RO and RT assessments are under investigation for the purpose of adapting this study to routine practice. Patients identified that they were comfortable with the RTs conducting their reviews and felt the RTs were capable of identifying when the RO needed to be informed involved. Conclusion: TORToise has given us an opportunity to begging formally recording patient toxicities using an electronic medium and could be the basis for site specific treatment toxicity profiling. A major challenge of the project was ensuing consistency in toxicity scores, comparison of our numerical values and written observations reveal inconsistencies, this is an area that will have to be developed if RTs are to record toxicities on a regular basis. This project will hopefully be adapted into current practice where all breast patients will be assessed by RTs routinely for treatment toxicity.

Introduction: The right inferior pulmonary vein (RIPV) recess may accumulate fluid and mimic a mass. We aim to determine the annual incidence of the RIPV recess pseudotumour and explore the relationship between the pseudotumour and cardiorespiratory disease. Methods: RIPV pseudotumour presence (sign positive) or absence (sign negative) was retrospectively assessed in 673 CT pulmonary angiograms CTPA’s performed over 2 years. All records were evaluated for pulmonary embolism (PE), acute pulmonary oedema (APO) and main pulmonary arterial dilatation (MPAD). The pseudotumour was followed on any CT imaging occurring in the subsequent 6 years with size and morphology noted. The possible relationship between the pseudotumour and cardiorespiratory states was assessed using the Chi square test. Logistic regression was employed to assess the influence of age and gender on the pseudotumour. Results: 673 patients had a CTPA between January 2007 and December 2008. 112 (17%) patients had a RIPV pseudotumour (sign positive). Patients with PE were significantly more likely to have a RIPV pseudotumour than those without (p < 0.001). Patients with APO were less likely to have a pseudotumour sign (p value 0.0148, odds ratio 0.44), while there was no relationship between the pseudotumour and patients with MPAD. There was no relationship between pseudotumour presence and gender, however, the sign was seen less commonly in patients less than 50 years of age (p = 0.0082, odds ratio 0.46). Conclusions: The RIPV pseudotumour is commonly seen in CTPA’s and should not be mistaken for a pathological lymphadenopathy. Its presence is more commonly seen in patients with PE, and those over the age of 50 years. Care should be taken to call a pseudotumour sign in patients younger than 50 years, especially without a known history of malignancy or infection. The pseudotumour is less commonly seen in patients with APO than without, and no significant association is seen in relation to patients who had CT signs of PAH.

1

Shoalhaven and Illawarra Cancer Care Centre, 2University


Scientific Exhibits Mammography screening and participation in Papua New Guinea K Spuur1,2 and R Pape1 1

CQUniversity, 2Charles Sturt University, Queensland,

Australia Aim: Reports have shown that the incidence of breast cancer in Papua New Guinea (PNG), increased dramatically in the late 1900s. Since the introduction of Mammographic Breast Screening in late 2005, more than 3,000 women have participated in a nationwide free screening program sponsored by the PNG Motor Vehicle Insurance Limited (MVIL) at the Pacific International Hospital (PIH) in Port Moresby. There is however a lack of effective participation of women in mammography screening services in PNG. The aim of this paper is to describe the factors contributing to low participation of mammography screening service by PNG women. Method: A descriptive review of various factors contributing to the low participation of PNG women as described by women who have undergone mammography examination at PIH between August 2006 and July 2010. The review examined: environmental factors, political factors, social factors, financial factors, cultural factors and health factors. The other variables that were studied include: age, parity and the use of hormonal replacement therapy (HRT). Approval and permission to collect data was granted from the Medical Director and Chief Operating Officer of PIH Private Hospital. Results: Although the female population in PNG is more than 2,000,000 according to PNG census within the late 1900s, only a few (

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