Radiation Protection Dosimetry Advance Access published February 16, 2015 Radiation Protection Dosimetry (2015), pp. 1–4

doi:10.1093/rpd/ncv007

PATIENT RADIATION DOSES IN VARIOUS FLUOROSCOPICALLY GUIDED ORTHOPAEDIC PROCEDURES V. Tsapaki1,*, I. A. Tsalafoutas2, D. Fagkrezos1, I. Lazaretos3, V. S. Nikolaou3 and N. Efstathopoulos3 1 Radiology Department and Medical Physics Unit, Konstantopouleio General Hospital, Agias Olgas 3-5, Nea Ionia 14233, Greece 2 Medical Physics Department, Agios Savvas Hospital, 171 Alexandras Av, Athens 11522, Greece 3 2nd Department of Trauma and Orthopedics, National and Kapodistrian University of Athens, Athens, Greece

Received 7 August 2014; revised 16 January 2015; accepted 17 January 2015 All orthopaedic fluoroscopic procedures performed using C-arm guidance were monitored for 1 y. The type of procedure, fluoroscopy time (T ), kerma – area product (KAP) values and number of radiographs (F) were recorded. The two most often performed techniques were as follows: intramedullary nailing (IMN) of intertrochanteric/peritrochanteric (IP) fractures (101 cases, 49.3 %) and antergrade IMN of femur or tibia shaft (TS) fractures (28 cases, 13.7 %). For the remaining procedures, none accounted for >5 %, categorised as ‘various’ (76 cases, 37 %). Large variations in T, KAP and F were observed. For IMN of IP fractures, antergrade IMN of femur and TS fractures and for various procedures, respectively, median values were T—2.1, 2.2 and 0.6 min, KAP—6.3, 6.3 and 0.6 Gy cm22 and F—21, 2.2 and 6.7. The patient doses during fluoroscopically guided procedures are relatively low compared with other interventional procedures.

INTRODUCTION The use of mobile C-arm X-ray units in orthopaedic surgical operations has been expanded in the last years due to the introduction of new techniques, which require fluoroscopy for guidance of the surgeons’ manipulations(1). In this way, orthopaedic surgeries can be performed with greater ease, in less time and with the least possible traumatising of the patient tissues and with fewer complications. One of the most common applications of fluoroscopic guidance in orthopaedic surgeries is femoral and hip fractures whose incidence worldwide is steadily increasing(2). Although such fractures often occur in frail elderly individuals, young adults, adolescents and children may also sustain femoral or hip fractures(3 – 7). The treatment of choice for patients with fracture of the femur or hip is early surgical stabilisation. A variety of implants and methods for fracture fixation are available, which all require fluoroscopic guidance(8, 9). It must be also mentioned that, apart from guidance, fluoroscopic and radiographic images are also used to assure and document the outcome of these procedures, before the patient exits the surgery room. The steadily increasing use of fluoroscopy in modern orthopaedic trauma practice has raised some concerns regarding the potential risks from the radiation exposure of patients (stochastic and deterministic effects of radiation)(10 – 16). One of the main reasons for these concerns is that orthopaedic procedures are usually performed outside radiological

departments, without the presence of a radiologist and most often without the presence of a radiation technologist either, by orthopaedic surgeons with questionable knowledge and training on radiation protection and procedure optimisation(1, 16). Furthermore, C-arms are not always equipped with dosimetric equipment and even if they are, often the total dose and fluoroscopy time is not recorded. This probably explains why the literature concerning patient doses during fluoroscopically guided orthopaedic surgeries is currently limited. Taking into account the above-mentioned issues, the authors performed a retrospective study concerning patient doses in fluoroscopic guided orthopaedic procedures performed in a university hospital operating theatre equipped with a mobile C-arm unit. MATERIALS AND METHODS In the orthopaedic procedures performed under fluoroscopic guidance, a mobile fluoroscopic C-arm unit (Ziehm 8000, Instrumentarium imaging, Finland) with a 23-cm-diameter image intensifier and two magnification modes (15 and 10 cm, respectively) is used. This unit offers automatic adjustment of the fluoroscopic tube potential and current (automatic brightness control system), depending on the anatomical area examined and the size of the patient. Conventional radiographs can be acquired in a 24`  30 cm2 cassette positioned within a cassette holder (in front of the image intensifier). The C-arm is equipped

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*Corresponding author: [email protected]

V. TSAPAKI ET AL.

RESULTS Data for a total of 205 orthopaedic procedures were recorded. The two most often performed techniques were as follows: (1) intramedullary nailing (IMN) of intertrochanteric/peritrochanteric fractures (101 cases, 49.3 %) and (2) antergrade IMN of femur or TS fractures (28 cases, 13.7 %). For the rest of the recorded procedures, none accounted for .5 % of the studied sample, so they all categorised as ‘various’ (76 cases, 37 %), reducing the initial categories number from 8 to 3. The main results are shown in Table 1. It must be noted that large variations in T, KAP and the number of radiographs were observed among different patients that underwent the same procedure. Another finding of the study is that the highest age group undergoes the intramedullary nailing (IMN) of intertrochanteric/peritrochanteric fractures (mean

age: 81.6 y), whereas the youngest age group undergoes internal or external fixation (mean age: 55.7 y). There is high correlation between fluoroscopy time and patient dose. The highest correlation between patient dose (KAP) and fluoroscopy time (T ) was found in IMN of intertrochanteric/peritrochanteric fractures (r: 0.81), followed by IMN of femur or TS fractures (r ¼ 0.78). Although the study did not include any operator radiation dose measurements, it is interesting to note that the monthly badges that the TLD badges of all medical staff involved in these procedures reported zero (,0.1 mGy) radiation dose values. This fact does not mean that the staff is not exposed to any radiation dose at all. It can also mean that the staff does not regularly wear the badge while in the surgery room, as already underlined in the latest ICRP report (1). Another reason, specifically for staff assisting the operator, could also be that it moves away from the X-ray machine or stays behind protective shielding whenever possible. Operator lens of eye monitoring was also not included in this study but has been shown to be important (1, 20) but manageable in the orthopaedic suite(21). DISCUSSION From the dosimetric results of Table 1, it is evident that orthopaedic surgeries typically result in lower radiation dose and risk for patients compared with other interventional procedures such as cardiology or angiography techniques(1). The high correlation between fluoroscopy time and patient dose can be attributed to the difficulty of these procedures, which require long use of fluoroscopy. Generally, the literature is limited regarding KAP in these types of procedures. From all the types of orthopaedic procedures performed in the authors’ hospital, only for IMN of shaft of femur KAP data were found in the international literature(13, 14). Table 2 presents the results of this comparison. It seems that similar results are found among the three authors for the specific procedure. For the commonly performed procedures (IMN of peritrochanteric fractures, open reduction and internal fixation of malleolar fractures and intramedullary nailing of diaphyseal fractures of the femur), the

Table 1. Median values (and ranges) of fluoroscopy time (T ), KAP and radiographic acquisitions (F ). Category (1) IMN of IP fractures (2) IMN of shaft of femur/tibia fractures (3) Various

# (%)

T (min)

KAP (Gy cm22)

F

101 (49) 28 (14) 76 (37)

2.1 (0.1–7.0) 2.2 (0.2–16.4) 0.6 (0.5–1.4)

6.3 (0.4–25.8) 6.3 (0.3–35.8) 0.6 (0.5–2.1)

21 (10– 72) 22 (9–81) 6.7 (6–15)

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with a kerma–area product (KAP) meter, and the cumulative KAP reading is given with digital indications in the unit’s control panel along with the cumulative fluoroscopy time. During a whole year, all orthopaedic surgical procedures carried out under fluoroscopic guidance were monitored. For each procedure, procedure type, fluoroscopy time (T ) in minutes, patient dose in terms of KAP in Gray per centimetre and number of radiographic acquisitions (F) were recorded. An initial categorisation of the procedure was as follows: (1) intramedullary nailing (IMN) of intertrochanteric/peritrochanteric fractures, (2) antergrade IMN of femur or tibia shaft (TS) fractures, (3) tibial condyles fractures (internal fixation/external fixation), (4) colles fractures, (5) internal fixation with screws of femoral neck fracture, (6) retrograde IMN of femoral shaft fractures, (7) external fixation of fractures and (8) ‘others’ not included in none of the above-mentioned categories. It should be noted that the X-ray machine was under a complete quality-control program for consistency of performance, according to national and international standards(17, 18). Furthermore, the KAP meter was calibrated according to the UK National Protocol for Patient Dose Measurements in Diagnostic Radiology(19). The uncertainty in the reading of both instruments, as quoted by the manufacturer, was +4 % for tube potentials ranging from 50 to 100 kVp.

DOSES IN FLUOROSCOPY GUIDED ORTHOPAEDIC PROCEDURES Table 2. Comparison of KAP and fluoroscopy time (T ) in IMN of shaft of femur. Author This study Malek(13) Tsalafoutas(14)

t (min)

KAP (Gy cm22)

2.2 2.5 3.0

6.3 5.4 not available

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Maximise source-to-skin distance and minimise source to image receptor distance. Avoid steep gantry angulations when possible.

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Keep unnecessary body parts out of the X-ray beam. Use pulsed fluoroscopy at a low pulse rate. Use low fluoroscopy dose rate settings. Collimate the X-ray beam to limit the size of radiation field to the area of interest. Use magnification only when it is essential. Image acquisition should not be used as a substitute for fluoroscopy. Minimise fluoroscopy time. Monitor patient dose.

Currently, the trend among many orthopaedic surgeons is to strive for minimal invasiveness when performing surgery. Through the collective initiative of medicine and industry, new technologic advances have emerged, enabling orthopaedic surgeons to execute procedures with much less soft tissue damage and resultant morbidity for the patient. Unfortunately, operating in this manner creates a heightened dependence on indirect visualisation to view pertinent anatomy. Thus, radiation exposure of the patient and surgical team has increased commensurately with this pursuit. Although some surgeons conform to the philosophy of as low as reasonably achievable, others exhibit a much more cavalier attitude towards radiation safety(1). In many teaching institutions, this nonchalance is often passed along to trainees through the practice of careless habits and ignorance of basic radiation safety principles. The authors did not find any guidelines from professional orthopaedic societies related to the subject of radiation protection and training. All these reveal the great need, not only for continuous monitoring of radiation doses but also for close collaboration between medical physicists or radiation protection officers, who are responsible for radiation safety within the hospital, and orthopaedic surgeons for successful optimisation of these procedures and efficient promotion of radiation safety culture. The main limitations of the study are the low number of patients and the limited number of parameters investigated. The literature search revealed the limited data reported on radiation dose in the large variety of orthopaedic procedures. In the near future, a more detailed investigation that will also include parameters such as effective dose, entrance skin dose and entrance surface dose in a larger sample of patients is already planned. CONCLUSIONS Patient doses during fluoroscopically guided procedures measured in the authors’ orthopaedic theatre are relatively low compared with other interventional procedures (e.g. DSA angiography). However, since the patient dose is largely dependent on the proper use of fluoroscopy, all orthopaedic departments need to investigate their practices and the resulting patient exposures during such procedures.

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respective mean fluoroscopy times found in the literature were 3.2, 1.5 and 6.3 min whereas the estimated mean entrance skin doses were 183, 21 and 331 mGy, respectively(14). In this study, mean fluoroscopy time of IMN of intertrochanteric/peritrochanteric fractures was 2.3 min and median KAP was 6.3 Gy cm22. Generally, the patient doses recorded in this study (as represented by KAP) were well below the respective values reported for other interventional procedures. The effective dose to patients with femoral fracture treated surgically is within the 11.6 –21.7 mSv range(22). Effective dose to patients for nailing osteosynthesis of proximal peritrochanteric fractures has been reported to average 14 mSv, whereas the effective dose to patients for lower extremity fractures is on average 100 mSv(23). Orthopaedic trauma surgeons are often responsible for stabilising pelvic fractures. C-arm fluoroscopy is indispensable to the trauma surgeon for guiding bony reduction and implant placement adjacent to major neurovascular structures. Given the large crosssectional diameter of the pelvis, fluoroscopic pelvic imaging has the potential to produce increased exposure to the patient and surgeon. Exposure data have been collected during pelvic phantom imaging and have demonstrated considerably high dose rate within the primary beam at the patient’s entrance surface (40 mGy min21)(24). Other studies have found that, during femoral or tibial fracture nailing, entrance skin dose to the patient is 183 mGy for 3.2 min of mean fluoroscopy time(14). The same study has examined patient exposure during pedicle screw placement in both the lumbar and cervical spine. Surgical time for these cases averaged from less than a minute to 7.7 min, which produced average entrance surface dose of 46 and 173 mGy for the lumbar spine and for the cervical spine, respectively. Associated ranges are 18 – 118 and 5 –407 mGy(14). Despite the fact that radiation effects and skin injuries have not been reported as a result of procedures conducted by orthopaedic surgeons, it is vital that users ‘know’ their machines and be familiar with ways to optimise their techniques(1). Below a summary of these optimisation ways as reported in the latest ICRP report is shown(1):

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Patient radiation doses in various fluoroscopically guided orthopaedic procedures.

All orthopaedic fluoroscopic procedures performed using C-arm guidance were monitored for 1 y. The type of procedure, fluoroscopy time (T), kerma-area...
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