1975, British Journal of Radiology, 48, 1039
DECEMBER 1975
Correspondence Recurrent pyogenic cholangitis is a disease with characteristic radiological manifestations (Wastie and Cunningham, 1973) occurring in South East Asia and in emigrants from these countries to North America and Europe. Yours, etc., M. L. WASTIE.
Department of Diagnostic Radiology, King's College Hospital, Denmark Hill, London SE5 9RS.
I would like to thank both you and Dr. Wastie for his very interesting and provocative letter. Yours, etc., R.JACOBS.
Department of Radiology, University of California, San Francisco 94110.
REFERENCES
REFERENCES
Ho, C. S., and WESSON, D. E., 1974. Recurrent pyogenic
cholangitis in Chinese immigrants. American Journal of Roentgenology, 122, 368-374.
Ho, C. S., and WESSON, D. E., 1974. Recurrent pyogenic
cholangitis in Chinese immigrants. American Journal of Roentgenology, 122, 368-374.
JACOBS, R. P., and PALUBINSKAS, A. J., 1975. Angiographic
findings of a choledochal cyst. British Journal of Radiology, 48, 51-52.
JACOBS, R. P., and PALUBINSKAS, A. J., 1975. Angiographic
findings of choledochal cyst. British Journal of Radiology, 48, 51-52.
WASTIE, M. L., and CUNNINGHAM, I. G. E., 1973. Roent-
genologic findings in recurrent pyogenic cholangitis.
WASTIE, M. L., and CUNNINGHAM, I. G. E., 1973. Roent-
genologic findings in recurrent pyogenic cholangitis.
American Journal of Roentgenology, 119, 71—77.
American Journal of Roentgenology, 119, 71—77'.
Editor's note—We are reprinting the following letter from Dr. G. M. Owen, which was originally published in BRITISH JOURNAL OF RADIOLOGY, July 1975, pages 610-611. UnforTHE EDITOR—SIR, ANGIOGRAPHIC FINDINGS OF A CHOLEDOCHAL CYST
Referring to the case report on the angiographic findings of a choledochal cyst, I appreciate the opportunity to reply to Dr. Wastie's letter and to investigate a disease entity (recurrent pyogenic cholangitis) with which I was unfamiliar. We feel that the patient we described (Jacobs and Palubinskas, 1975) did not have pyogenic cholangitis and that her radiographic findings are explicable by her choledochal cyst. Unlike patients with recurrent pyogenic cholangitis (Wastie and Cunningham, 1973), our patient had neither recurrent fevers nor chills. Bile which was withdrawn from her gall bladder and her choledochal cyst at the time of surgery exhibited no cells or bacteria by microscopic examination. Bile samples cultured for bacteria exhibited no growth. The choledochal cyst in our patient was drained of two litres of liquid green bile which did not contain concretions. No strictures, stones or sediment of any kind were seen in her biliary tree despite careful palpation and multiple cholangiograms at the time of surgery. The biliary tree of patients with recurrent pyogenic cholangitis is said to ". . . contain soft pigment stones, biliary mud or pus" (Wastie and Cunningham, 1973). Of the five patients described by Ho and Wesson (1974) four had fevers, five had biliary stones or sludge, four had organisms cultured from blood or bile. Our patient satisfied none of these criteria. Drs. Ho and Wesson (1974) noted the "arrow-head sign" in only one of their five patients. Though they state that recurrent pyogenic cholangitis has a "characteristic" radiologic appearance, Caroli's disease, sclerosing cholangitis and extrahepatic biliary obstruction are all included in their radiologic differential diagnosis. Can a radiologist definitively diagnose recurrent pyogenic cholangitis by evaluating only the calibre and shape of the bile ducts ? I know of no study in which the cholangiographic specificity of these observations has been critically investigated. We feel that: (1) tapering of peripheral intrahepatic ducts with dilated central ducts is a non-pathognomonic observation which may be seen with extrahepatic biliary obstruction; (2) our patient has a surgically proven choledochal cyst—an entity known to cause recurrent episodes of extrahepatic biliary obstruction; (3) the diagnosis of recurrent pyogenic cholangitis in our patient is clinically and bacteriologically untenable.
tunately at the last stage of correcting proofs of the original version we were over enthusiastic and edited out the very anomalies which were the original stimulus to Dr. Owen's letter. We apologise to the author for being, on this occasion, too consistent in dealing with s's and z's. THE EDITOR—SIR, TERMINOLOGY IN RADIATION PROTECTION
It is widely known that there is a high probability that the Euratom Treaty will shortly affect radiological protection (otherwise known as health physics or radiation safety) in hospitals, research establishments and medical schools throughout the United Kingdom. It is hoped that the various organizations concerned, which include the British Institute of Radiology, will take advantage of the opportunity and adopt a more uniform terminology in place of the variations used at present in the two "Codes of Practice", one issued by the Department of Health and Social Security and the other by the Department of Employment, and also the Universities Handbook (Committee of Vice-Chancellors and Principals). Although the three publications advocate very similar administrative structures, most of the possible combinations of relevant words are used (Table I). Notwithstanding the connotations of the 1920s, to most readers of your Journal, "radiology" is the work undertaken in diagnostic X-ray departments and does not refer to saturation analysis, radiotherapy and the safe disposal of radioactive waste. The word "radiation" includes these topics and many others. It is more difficult to choose between "safety" and "protection": although the links of the latter with unsavoury illegal practices may be an argument for using the former. The exact difference between an officer and an adviser are not at all obvious especially when the titles seem interchangeable ; the Department of Health and Social Security has a Radiological Protection Adviser and a Supervisory Medical Officer but the Department of Employment has a Safety Officer and a Medical Adviser. The types of radiation to be included are of course another matter of debate. The BRITISH JOURNAL OF RADIOLOGY publishes papers on ultra-
sonic radiation. Recently the N.R.P.B. undertook some responsibilities regarding safety from microwaves and lasers. In one report {Nature, 1974) there was an implication that the "R" in N.R.P.B. now stood for "radiation" although this may have been a printing error. In one ICRP report (ICRP, 1964) radionuclides are separated according to their toxicity into "groups". For a similar purpose the Department of Employment uses
1039
1975, British Journal of Radiology, 48, 1040-1041 Correspondence THE EDITOR—SIR, THE RADIOGRAPHY OF POLYMETHYL METHACRYLATE (PERSPEX)
TABLE I ADMINISTRATIVE PERSONNEL
Department of Health and Social Security Institution
Many workers, including ourselves, have from time to time used Perspex (Lucite), polymethyl methacrylate, as a convenient phantom material. Rini et al. (1973) used a Lucite step-wedge in water as a phantom for part of a study into mammographic technique up to 40 kVp. For some of our studies we duplicated this procedure to cover the range from 20 to 120 kVp and observed that at low kVp the Perspex was relatively less radio-opaque than a similar thickness of water. With increasing kV the opacity, relative to water, increased until at about 50 kVp the opacities were identical and the Perspex could not be seen in the water. At 70 kVp the Perspex was more opaque than the same thickness of water (Fig. 1). Hemmingsson and Jung (1973) have calculated the absorption coefficients of a number of materials relative to water and demonstrated the reversal of absorption of methyl methacrylate at similar energy ranges. This phenomenon does not appear to be widely appreciated and may lead to erroneous conclusions when the material is used as a
Department Committee of of ViceEmployment Chancellors
Radiological Radiological Authoritative or Safety Safety Committee Management Committee Committee Radiological Radiological Radiation Protection Safety Protection Officer Adviser Officer
Department
Radiological Departmen- Departmental Safety tal Officer Radiological Radiation Supervisor Safety Officer
"classes" and the Department of Health and Social Security compromises by using "groups" and "classes". If "classes" were used for toxicity, then "groups" could be used for transport, laboratories could be "graded" and workers placed in "categories". Interested bodies, such as the N.R.P.B., the A.U.R.P.O., the H.P.A. and the B.R.P.A. might be asked by the British Institute of Radiology for their comments on these and other well-known terminological difficulties. From the covers of the two Codes we see that the Department of Employment protects against ionising radiations while the Department of Health and Social Security is concerned with ionising radiations. Inter-Departmental consistency would be appreciated in spelling as well as terminology. Yours, etc., G. M. OWEN.
Department of Medical Physics, University Hospital of Wales, Cardiff CF4 4XW. (N.R.P.B., A.U.R.P.O., H.P.A., B.R.P.A. and other relevant initialled bodies, including perhaps the Editorial Staff associated with H.M.S.O. please note! Editor.) REFERENCES Code of Practice for the Protection of Persons against Ionizing Radiations arising from Medical and Dental Use, 1972 FIG 1. (Department of Health and Social Security, H.M.S.O., London). Radiograph of a water-bath 6 cm deep containing a vertical Code of Practice for the Protection of Persons exposed to Ionis-Perspex rod 27-5 mm in diameter, 5 cm high. On top of the ing Radiations in Research and Teaching, 1971 (Department rod a ball-bearing was held in place by cellulose tape. At 24 of Employment, H.M.S.O., London). kVp the Perspex rod appears as a black circle with the ballCOMMITTEE OF VICE-CHANCELLORS AND PRINCIPALS OF THE bearing at the centre. At 40 kVp the rod appears relatively UNIVERSITIES OF THE UNITED KINGDOM, 1972. Radiologimore opaque and in the original radiograph two blacker cal Protections in Universities. (The Association of Com- air bubbles can be seen adjacent to the ball-bearing, the air monwealth Universities, London). being trapped under the cellulose tape holding it. At 55 Nature, 1974. "More Radiation Protection", 250, pp. 528- kVp the Perspex is virtually indistinguishable from the 529. water though the air bubbles can still be seen. At 70 kVp the INTERNATIONAL COMMISSION ON RADIOLOGICAL PROTECTION Perspex rod now appears to be of greater opacity than the 1964. Report of Committee 5 on the Handling and Disposal water. At 120 kVp trie opacity of the Perspex has increased; of Radioactive Materials in Hospitals and Medical Research the air bubble can still, be seen. Focus film distance was Establishments. ICRP Publication No. 5, p. 7 (Perga- 100 cm. The total nitration 0-62 mm Al equivalent, Kodak mon Press, Oxford). Kodirex Auto Process film, Tungsten target.
1040
DECEMBER 1975
Correspondence Recurrent pyogenic cholangitis is a disease with characteristic radiological manifestations (Wastie and Cunningham, 1973) occurring in South East Asia and in emigrants from these countries to North America and Europe. Yours, etc., M. L. WASTIE.
Department of Diagnostic Radiology, King's College Hospital, Denmark Hill, London SE5 9RS.
I would like to thank both you and Dr. Wastie for his very interesting and provocative letter. Yours, etc., R.JACOBS.
Department of Radiology, University of California, San Francisco 94110.
REFERENCES
REFERENCES
Ho, C. S., and WESSON, D. E., 1974. Recurrent pyogenic
cholangitis in Chinese immigrants. American Journal of Roentgenology, 122, 368-374.
Ho, C. S., and WESSON, D. E., 1974. Recurrent pyogenic
cholangitis in Chinese immigrants. American Journal of Roentgenology, 122, 368-374.
JACOBS, R. P., and PALUBINSKAS, A. J., 1975. Angiographic
findings of a choledochal cyst. British Journal of Radiology, 48, 51-52.
JACOBS, R. P., and PALUBINSKAS, A. J., 1975. Angiographic
findings of choledochal cyst. British Journal of Radiology, 48, 51-52.
WASTIE, M. L., and CUNNINGHAM, I. G. E., 1973. Roent-
genologic findings in recurrent pyogenic cholangitis.
WASTIE, M. L., and CUNNINGHAM, I. G. E., 1973. Roent-
genologic findings in recurrent pyogenic cholangitis.
American Journal of Roentgenology, 119, 71—77.
American Journal of Roentgenology, 119, 71—77'.
Editor's note—We are reprinting the following letter from Dr. G. M. Owen, which was originally published in BRITISH JOURNAL OF RADIOLOGY, July 1975, pages 610-611. UnforTHE EDITOR—SIR, ANGIOGRAPHIC FINDINGS OF A CHOLEDOCHAL CYST
Referring to the case report on the angiographic findings of a choledochal cyst, I appreciate the opportunity to reply to Dr. Wastie's letter and to investigate a disease entity (recurrent pyogenic cholangitis) with which I was unfamiliar. We feel that the patient we described (Jacobs and Palubinskas, 1975) did not have pyogenic cholangitis and that her radiographic findings are explicable by her choledochal cyst. Unlike patients with recurrent pyogenic cholangitis (Wastie and Cunningham, 1973), our patient had neither recurrent fevers nor chills. Bile which was withdrawn from her gall bladder and her choledochal cyst at the time of surgery exhibited no cells or bacteria by microscopic examination. Bile samples cultured for bacteria exhibited no growth. The choledochal cyst in our patient was drained of two litres of liquid green bile which did not contain concretions. No strictures, stones or sediment of any kind were seen in her biliary tree despite careful palpation and multiple cholangiograms at the time of surgery. The biliary tree of patients with recurrent pyogenic cholangitis is said to ". . . contain soft pigment stones, biliary mud or pus" (Wastie and Cunningham, 1973). Of the five patients described by Ho and Wesson (1974) four had fevers, five had biliary stones or sludge, four had organisms cultured from blood or bile. Our patient satisfied none of these criteria. Drs. Ho and Wesson (1974) noted the "arrow-head sign" in only one of their five patients. Though they state that recurrent pyogenic cholangitis has a "characteristic" radiologic appearance, Caroli's disease, sclerosing cholangitis and extrahepatic biliary obstruction are all included in their radiologic differential diagnosis. Can a radiologist definitively diagnose recurrent pyogenic cholangitis by evaluating only the calibre and shape of the bile ducts ? I know of no study in which the cholangiographic specificity of these observations has been critically investigated. We feel that: (1) tapering of peripheral intrahepatic ducts with dilated central ducts is a non-pathognomonic observation which may be seen with extrahepatic biliary obstruction; (2) our patient has a surgically proven choledochal cyst—an entity known to cause recurrent episodes of extrahepatic biliary obstruction; (3) the diagnosis of recurrent pyogenic cholangitis in our patient is clinically and bacteriologically untenable.
tunately at the last stage of correcting proofs of the original version we were over enthusiastic and edited out the very anomalies which were the original stimulus to Dr. Owen's letter. We apologise to the author for being, on this occasion, too consistent in dealing with s's and z's. THE EDITOR—SIR, TERMINOLOGY IN RADIATION PROTECTION
It is widely known that there is a high probability that the Euratom Treaty will shortly affect radiological protection (otherwise known as health physics or radiation safety) in hospitals, research establishments and medical schools throughout the United Kingdom. It is hoped that the various organizations concerned, which include the British Institute of Radiology, will take advantage of the opportunity and adopt a more uniform terminology in place of the variations used at present in the two "Codes of Practice", one issued by the Department of Health and Social Security and the other by the Department of Employment, and also the Universities Handbook (Committee of Vice-Chancellors and Principals). Although the three publications advocate very similar administrative structures, most of the possible combinations of relevant words are used (Table I). Notwithstanding the connotations of the 1920s, to most readers of your Journal, "radiology" is the work undertaken in diagnostic X-ray departments and does not refer to saturation analysis, radiotherapy and the safe disposal of radioactive waste. The word "radiation" includes these topics and many others. It is more difficult to choose between "safety" and "protection": although the links of the latter with unsavoury illegal practices may be an argument for using the former. The exact difference between an officer and an adviser are not at all obvious especially when the titles seem interchangeable ; the Department of Health and Social Security has a Radiological Protection Adviser and a Supervisory Medical Officer but the Department of Employment has a Safety Officer and a Medical Adviser. The types of radiation to be included are of course another matter of debate. The BRITISH JOURNAL OF RADIOLOGY publishes papers on ultra-
sonic radiation. Recently the N.R.P.B. undertook some responsibilities regarding safety from microwaves and lasers. In one report {Nature, 1974) there was an implication that the "R" in N.R.P.B. now stood for "radiation" although this may have been a printing error. In one ICRP report (ICRP, 1964) radionuclides are separated according to their toxicity into "groups". For a similar purpose the Department of Employment uses
1039
1975, British Journal of Radiology, 48, 1040-1041 Correspondence THE EDITOR—SIR, THE RADIOGRAPHY OF POLYMETHYL METHACRYLATE (PERSPEX)
TABLE I ADMINISTRATIVE PERSONNEL
Department of Health and Social Security Institution
Many workers, including ourselves, have from time to time used Perspex (Lucite), polymethyl methacrylate, as a convenient phantom material. Rini et al. (1973) used a Lucite step-wedge in water as a phantom for part of a study into mammographic technique up to 40 kVp. For some of our studies we duplicated this procedure to cover the range from 20 to 120 kVp and observed that at low kVp the Perspex was relatively less radio-opaque than a similar thickness of water. With increasing kV the opacity, relative to water, increased until at about 50 kVp the opacities were identical and the Perspex could not be seen in the water. At 70 kVp the Perspex was more opaque than the same thickness of water (Fig. 1). Hemmingsson and Jung (1973) have calculated the absorption coefficients of a number of materials relative to water and demonstrated the reversal of absorption of methyl methacrylate at similar energy ranges. This phenomenon does not appear to be widely appreciated and may lead to erroneous conclusions when the material is used as a
Department Committee of of ViceEmployment Chancellors
Radiological Radiological Authoritative or Safety Safety Committee Management Committee Committee Radiological Radiological Radiation Protection Safety Protection Officer Adviser Officer
Department
Radiological Departmen- Departmental Safety tal Officer Radiological Radiation Supervisor Safety Officer
"classes" and the Department of Health and Social Security compromises by using "groups" and "classes". If "classes" were used for toxicity, then "groups" could be used for transport, laboratories could be "graded" and workers placed in "categories". Interested bodies, such as the N.R.P.B., the A.U.R.P.O., the H.P.A. and the B.R.P.A. might be asked by the British Institute of Radiology for their comments on these and other well-known terminological difficulties. From the covers of the two Codes we see that the Department of Employment protects against ionising radiations while the Department of Health and Social Security is concerned with ionising radiations. Inter-Departmental consistency would be appreciated in spelling as well as terminology. Yours, etc., G. M. OWEN.
Department of Medical Physics, University Hospital of Wales, Cardiff CF4 4XW. (N.R.P.B., A.U.R.P.O., H.P.A., B.R.P.A. and other relevant initialled bodies, including perhaps the Editorial Staff associated with H.M.S.O. please note! Editor.) REFERENCES Code of Practice for the Protection of Persons against Ionizing Radiations arising from Medical and Dental Use, 1972 FIG 1. (Department of Health and Social Security, H.M.S.O., London). Radiograph of a water-bath 6 cm deep containing a vertical Code of Practice for the Protection of Persons exposed to Ionis-Perspex rod 27-5 mm in diameter, 5 cm high. On top of the ing Radiations in Research and Teaching, 1971 (Department rod a ball-bearing was held in place by cellulose tape. At 24 of Employment, H.M.S.O., London). kVp the Perspex rod appears as a black circle with the ballCOMMITTEE OF VICE-CHANCELLORS AND PRINCIPALS OF THE bearing at the centre. At 40 kVp the rod appears relatively UNIVERSITIES OF THE UNITED KINGDOM, 1972. Radiologimore opaque and in the original radiograph two blacker cal Protections in Universities. (The Association of Com- air bubbles can be seen adjacent to the ball-bearing, the air monwealth Universities, London). being trapped under the cellulose tape holding it. At 55 Nature, 1974. "More Radiation Protection", 250, pp. 528- kVp the Perspex is virtually indistinguishable from the 529. water though the air bubbles can still be seen. At 70 kVp the INTERNATIONAL COMMISSION ON RADIOLOGICAL PROTECTION Perspex rod now appears to be of greater opacity than the 1964. Report of Committee 5 on the Handling and Disposal water. At 120 kVp trie opacity of the Perspex has increased; of Radioactive Materials in Hospitals and Medical Research the air bubble can still, be seen. Focus film distance was Establishments. ICRP Publication No. 5, p. 7 (Perga- 100 cm. The total nitration 0-62 mm Al equivalent, Kodak mon Press, Oxford). Kodirex Auto Process film, Tungsten target.
1040
