1976, British Journal of Radiology, 49, 298 Correspondence should be borne in mind that the majority of skeletal metastases originate in the bone marrow. In patients with known primary malignancy, negative X rays, but skeletal localized pain, we have obtained a diagnostic accuracy for metastases in excess of 90 per cent by using a polyphosphate complex with a significant bone marrow uptake (PolyphosphateDiagnostic Isotopes Inc.). Many of these lesions are visualized six months and more before they are detectable by other means. Similarly by using a bone specific reagent (Pyrophosphate BYK-Mallinckrodt) it has been possible to quantitatively evaluate the rate of ectopic bone formation following trauma. Clearly there are many things still to be learned regarding the nature of these various complexes and their application to clinical situations, but it is our belief that the view stated above best fits the known facts and that on this basis optimal interpretation of clinical situations can be made. Yours, etc., P. H. Cox. Department of Nuclear Medicine, Rotterdamsch Radio-Therapeutisch Instituut, Groene Hilledijk 297, Rotterdam, The Netherlands.
cited heretofore should be reduced by 8 per cent to bring them into accord with current dosimetry. Confusion can sometimes arise because some centres quote only the dose due to neutrons and ignore the dose due to the accompanying y radiation (e.g. Hammersmith) while other centres quote the total dose obtained by a simple addition of the dose due to the two components. For the irradiation of biological materials neither approach is strictly correct, the effective dose probably lying between these two extremes, owing to the different biological properties of the two types of radiation. The best procedure is to record separately both components of the total dose. Yours, etc., C. J. PARNELL, D. K. BEWLEY.
MRC Cyclotron Unit, Hammersmith Hospital, Ducane Road, London Wl 2 OHS. REFERENCE BEWLEY, D. K., MCCULLOUGH, E. C , PAGE, B. C , and
SAKATA, S., 1974. Neutron dosimetry with a calorimeter, Physics in Medicine and Biology, 19, 831-842.
REFERENCES
ANGHILERI, L. J., and MILLER, E. S., 1971. 51Cr polyphos-
THE EDITOR—SIR,
phates, their general behaviour in normal and tumour THE "SELF-REPORTING RADIOGRAPH" bearing animals. Journal of Nuclear and Biological MediWith reference to the letter from Rubem Pochaczevsky cine, 15,42-49. in THE BRITISH JOURNAL OF RADIOLOGY, 48, 65,1 suggest the Cox, P. H., 1974. »9Tcm complexes for skeletal scintigraphy. writer and others requiring quick, easily made small prints Physico-chemical factors affecting bone and bone uptake. of radiographs try using a Polaroid camera. For many years I British Journal of Radiology, 47, 845-850. have been producing in a few minutes prints of quality MERRICK, M. V., 1975. Review article: bone scanning. good enough for reproduction in medical journals using a British Journal of Radiology, 48, 327-351. vintage Polaroid equipped with a close-up lens kit. The YEH, S. H., and KRISS, J. P., 1967. Distribution and scinti- ideal set-up is to have the camera mounted on a rail adphotography of a new complex pentavalent technetium justable for distance and always centred on the middle of 99m citrate: studies in the rodent. Journal of Nuclear the film illuminator, and mark the rail to show area of Medicine, 8, 666-677. coverage and camera focal settings. However the tape provided with the lens kit and a pile of Journals is a workable substitute. These old cameras can be picked up cheaply from photographic stores and, if the results should not be satisfactory, they will be welcomed by the children. I find THE EDITOR—SIR, the makers recommended 10-second processing time is DOSIMETRY OF THE FAST NEUTRON BEAM PRODUCED better lengthened to 45 seconds. Perhaps this is something BY THE MRC CYCLOTRON The fast neutron beam produced by the Medical Re- to do with being in the southern hemisphere. search Council's cyclotron at Hammersmith Hospital, Yours, etc., London, has been in use for radiotherapy since 1966 and G. L. HARDMAN. for radiobiology for several years previous to that date. 26 Spring Gully Road, Since the inception of the fast neutron beam at Hammer- Bendigo, Victoria 3550, smith we have been concerned particularly with maintain- Australia. ing reproducible and internally consistent dosimetry, with the knowledge that the absolute accuracy with which the accepted unit of absorbed dose, the rad, could be realized was poor. However, the increasing use of fast neutrons for THE EDITOR—SIR, radiotherapy demands that all centres should have a comSHOULD WE REPORT EVERY FILM? mon basis for neutron dosimetry. Since no standardizing You ask in your editoral whether the radiologist must laboratory currently offers a calibration service for fast report every film. It would be more pertinent to ask whether neutron beams, further efforts have been devoted to im- he is physically capable of reporting every film. The present proving the accuracy of fast neutron dosimetry both at shortage of radiologists is likely to continue because of Hammersmith (e.g. Bewley et al., 1974) and elsewhere, diminishing recruitment, emigration, increasing quantitawhile physicists from Glasgow, Manchester, Houston and tive demands, widening horizons and expanding adminisWashington, D.C., have visited Hammersmith to carry out trative duties. A desirable standard of radiology cannot be intercomparisons. These measurements have indicated that maintained with a workload in excess of 5-12,000 examinathe 'Hammersmith' rad of neutrons represented 108 ergs/ tions per year, depending on the type of practice concerned. g. Consequently, from January 1, 1975, fast neutron dosi- Most radiologists' workload is at least half as high again. metry at Hammersmith was revised by 8 per cent to obtain What is to be done ? The importance of efficient departbetter consistency between the various centres. The dose mental organization is obvious. It is tempting to delegate prescribed for radiotherapy is now typically 1,560 rads or ignore administrative work, but this is a shortsighted given in 12 treatments in 26 days instead of 1,440 rads as policy. Departmental administration must remain firmly in prescribed previously. It must, however, be emphasized the hands of radiologists. We are not likely to reduce the that this does not result in an increase in the amount of total number of examinations performed, though the anradiation received by the patient. Also, all values of RBE nual increase reported by many departments should not be
298
cited heretofore should be reduced by 8 per cent to bring them into accord with current dosimetry. Confusion can sometimes arise because some centres quote only the dose due to neutrons and ignore the dose due to the accompanying y radiation (e.g. Hammersmith) while other centres quote the total dose obtained by a simple addition of the dose due to the two components. For the irradiation of biological materials neither approach is strictly correct, the effective dose probably lying between these two extremes, owing to the different biological properties of the two types of radiation. The best procedure is to record separately both components of the total dose. Yours, etc., C. J. PARNELL, D. K. BEWLEY.
MRC Cyclotron Unit, Hammersmith Hospital, Ducane Road, London Wl 2 OHS. REFERENCE BEWLEY, D. K., MCCULLOUGH, E. C , PAGE, B. C , and
SAKATA, S., 1974. Neutron dosimetry with a calorimeter, Physics in Medicine and Biology, 19, 831-842.
REFERENCES
ANGHILERI, L. J., and MILLER, E. S., 1971. 51Cr polyphos-
THE EDITOR—SIR,
phates, their general behaviour in normal and tumour THE "SELF-REPORTING RADIOGRAPH" bearing animals. Journal of Nuclear and Biological MediWith reference to the letter from Rubem Pochaczevsky cine, 15,42-49. in THE BRITISH JOURNAL OF RADIOLOGY, 48, 65,1 suggest the Cox, P. H., 1974. »9Tcm complexes for skeletal scintigraphy. writer and others requiring quick, easily made small prints Physico-chemical factors affecting bone and bone uptake. of radiographs try using a Polaroid camera. For many years I British Journal of Radiology, 47, 845-850. have been producing in a few minutes prints of quality MERRICK, M. V., 1975. Review article: bone scanning. good enough for reproduction in medical journals using a British Journal of Radiology, 48, 327-351. vintage Polaroid equipped with a close-up lens kit. The YEH, S. H., and KRISS, J. P., 1967. Distribution and scinti- ideal set-up is to have the camera mounted on a rail adphotography of a new complex pentavalent technetium justable for distance and always centred on the middle of 99m citrate: studies in the rodent. Journal of Nuclear the film illuminator, and mark the rail to show area of Medicine, 8, 666-677. coverage and camera focal settings. However the tape provided with the lens kit and a pile of Journals is a workable substitute. These old cameras can be picked up cheaply from photographic stores and, if the results should not be satisfactory, they will be welcomed by the children. I find THE EDITOR—SIR, the makers recommended 10-second processing time is DOSIMETRY OF THE FAST NEUTRON BEAM PRODUCED better lengthened to 45 seconds. Perhaps this is something BY THE MRC CYCLOTRON The fast neutron beam produced by the Medical Re- to do with being in the southern hemisphere. search Council's cyclotron at Hammersmith Hospital, Yours, etc., London, has been in use for radiotherapy since 1966 and G. L. HARDMAN. for radiobiology for several years previous to that date. 26 Spring Gully Road, Since the inception of the fast neutron beam at Hammer- Bendigo, Victoria 3550, smith we have been concerned particularly with maintain- Australia. ing reproducible and internally consistent dosimetry, with the knowledge that the absolute accuracy with which the accepted unit of absorbed dose, the rad, could be realized was poor. However, the increasing use of fast neutrons for THE EDITOR—SIR, radiotherapy demands that all centres should have a comSHOULD WE REPORT EVERY FILM? mon basis for neutron dosimetry. Since no standardizing You ask in your editoral whether the radiologist must laboratory currently offers a calibration service for fast report every film. It would be more pertinent to ask whether neutron beams, further efforts have been devoted to im- he is physically capable of reporting every film. The present proving the accuracy of fast neutron dosimetry both at shortage of radiologists is likely to continue because of Hammersmith (e.g. Bewley et al., 1974) and elsewhere, diminishing recruitment, emigration, increasing quantitawhile physicists from Glasgow, Manchester, Houston and tive demands, widening horizons and expanding adminisWashington, D.C., have visited Hammersmith to carry out trative duties. A desirable standard of radiology cannot be intercomparisons. These measurements have indicated that maintained with a workload in excess of 5-12,000 examinathe 'Hammersmith' rad of neutrons represented 108 ergs/ tions per year, depending on the type of practice concerned. g. Consequently, from January 1, 1975, fast neutron dosi- Most radiologists' workload is at least half as high again. metry at Hammersmith was revised by 8 per cent to obtain What is to be done ? The importance of efficient departbetter consistency between the various centres. The dose mental organization is obvious. It is tempting to delegate prescribed for radiotherapy is now typically 1,560 rads or ignore administrative work, but this is a shortsighted given in 12 treatments in 26 days instead of 1,440 rads as policy. Departmental administration must remain firmly in prescribed previously. It must, however, be emphasized the hands of radiologists. We are not likely to reduce the that this does not result in an increase in the amount of total number of examinations performed, though the anradiation received by the patient. Also, all values of RBE nual increase reported by many departments should not be
298
