Interview with John Thomas

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1 Dr. Eugene Pendergrass - Radiology at Penn Cyclotron-produced isotopes - the Delaware millicuries were different from the California millicuries! 2 . Discussion of where to discuss dosimetry in the book Who first calculated radiation dose from radioisotopes? Suggested talk to Reed Warren clinical medicine (now nuclear medicine) Most of the dosimetry has come from clinical medicine 4. YJRD - protection approach was not suited to clinical medicine - equilibrium situation so much used in protection, calculation seldom holds in clinical situations. 6. Re/Gaps in the internal emitter story 7 . Dose response relationships - radiation vs chemical toxicology 8. His career - he calls himself a physicist working in a In therapy situations need customized dosage calculation for

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~ I QI LR VIEW KITH JOHK THOMAS John? I ' d like to put on tape what you just told me. THOMAS: I n regard t o Chapter 6in your setting the stage for the cyclotron produced radioisotopes. When I first became active in the Radiation Protection business, w;iich was about 1951 o r 1952, Dr. Eugme P . Pendergrass was Chairman of the Department of Radiology atthe hospital a t the University of Pennsylvania. He was Chairman o f the Department 'of Radiology at the hospital a t the University of Pennsylvania, some thirty years. He was Chainnan i n the mid part of the 1930's atleast and remained active in tile department up until last year,when he re-located in Florida,and I think he still remains active with the department. radioisotopes and therapy, in particular,in the later 1930s and 1940s, and our sources o f supply were predominantly a cyclotron a t the Bio-chemical Research I can remember him talking about use o f cyclotron produced Foundation i n Newark, Delaware, and a cyclotron on the West Coast. STANNARD: The one a t Berkeley? THOMAS: Dr. Pendergrass observed that they had t o be careful in dczimetry t o be sure to use the Delaware milli curies or the California ' milli curies because their mi 11 i curi e rzti ngs were different enough to affect the therapy! one of my earliest rernernbrances. . STANNARD: That i s very interesting. THOMAS: Phosporous, and I believe 1-131. What were t h e isotopes, do you remember? section, and that ' s a good point,I haven ' t listed dosimetry as such. The primary re?san for not doing it is that the dosimetry i s somethin9 that has been discussed, As far as dosimetry goes, I thought I would put it in with the methodology

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want me t o do is try to fill in a lot of thing; that just haven't been dis - ? ;sed much. I am not going to try to say alot about methodology because really all you need t o do is refer to any standard textbook in Tracer about the reasons that methodology limited what people could do. On dosimetry, one thing 3 am anxious t o kncw, who really mad? the first calculation of a radiation dose from a radio n xli de ? ''Well, i t was Waldo Cohn during the early Manhattan Engineer District days", and there is a paper with that title in one o f the National Nuclear Energy series volumes that never got published. And Waldo told me on the What I do want t o do i s say something So far I'm a t the point where they say, phone that he had a copy ofit,but when he sent the material, i t wasn't wnat I was looking for. Nuclear medicine as such, o f course, didn ' t exist in those days. Just off hhnd,who would you select as the pioneer that calculated ' radiation doses from radionuclides first ? THOMAS: I couldn ' t select someone by name, Idon ' t believe,butI think i t would be the physicists working with the radiologist - therapists, probably estimate to pattern their dose. Tney would have t o do some kind of internal dosimetry !-lere radionuclides given i n what we now call nuclear medicine as THOMAS: (both talk f ng)... .memory of what other people have told ne. I believe probably by '38 o r '39 there was some medical use o f radionuclides, probably f o r maybe even leukemia treatment, I'm not sure. Iodine, o f course, large enough t o be called therapeutic. I hadn't realized that they had been used that early in doses I f so, you needed to calculate a dose, a radiation dose. THOMAS: Iwasn ' t active then. I would imagine Reed Warren may have had

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.contact,but1don ' t remember him ever talking about calculating internal C'TANNARD: That ' s a good poict. Well, Idon ' t know 2s i t ' s terribly important t o follow that up. on Discrete Source Therapy - radium dosimetry, in his earlier career. wouldn't be surprised but what he might not have been one o f the early cal - cula tors of some other kind cf internal nuclide dose. STANNARD: That ' s a good point. the man i n England. I ' d really rather know more about your interests I was coming into this ' through Parker (Herb) whose first definitive book I t was in the book that he wrote with STANNARD: I thought that was all external radiation calculations.That is external dose from radium, butI haven't seen the book yet. THOMAS: I t was external to the source, but sometimes the sources were internal I t was something like "Radium Dosimetry". have room to put in a great deal on that kind of therapy. referred to during those early days. The discrete source t o the field distribution calculations. I ' l l have t o give that area short shift because I just don ' t These were the people t o whom dosimetry questions might have been STANNARD: That book was late OS, ? ' m quite sure, because i t was before Parker went to Seattle (Thomas: Long before) THOMAS: I remember him from thyroid dosimetry with iodine and his concern over non-uniform distribution - khat it could do tothe dose. Ididn ' t even know who he was. STANMARD:. ....Idon ' t know whether this is a good question toask you , but the contrib ut jons of the old internal c:.i tter toxicology research, shift

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eo clinical medicine as itis now practiced, ssmething that must be fairly close to your background and interests. t!~t,WS:I may have a distorted view on that.I seem to feel that much o f the actual dosimetry has come from clinical medicine. STANNARD: That ' s a good poifit. i f you can determine where they arein the system as the absorbed fraction in the MIRD tables, which were started by a committee of the Society of Nuclear Medicine which fortunately attracted Walter Snyder's interest. Mzthodology i s now the simplest way t o ciilculate internal emitters t o be brought into existance? Was i t because the old business was mostly on continuous in take and occupational exposure? of the many new uses - we are trying to get a committee to bring together a s much information about many varied radionuclides and chemical forms and also to somewhat standardize the dose calculation procedures;- so my idea o f what the standard man geometrical distribution was and I ' v e always been a little puzzled asto why MIRD had t o be What was lacking i n what people had a t the time that MIR D had Partly,but wasn't Quimby's dated dose formula used i n the I think the MIRD tables came t o pass largely because someone else ' s idea wasn't the same. beautiful.....like Walter gotin and designed the computer base line. Now, of course, calculation of internal dose, zl t less tin organ avert ges,is relatively simple i f you can get the biological distribution and clearance data. Look it up in a computerized table. STANNARD: This is available from MIR D rather than from internal emitter toxi col ogy people. THOMAS: That ' s correct.It ' sthat the protection types of internal emitter dosimetry and limitations really weren't suited to a clinical situation where an individual was given a material - like technetium today with a six hour

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I think tb is is what was missing i n the literature from the prc tec tion side, ':o 'that medicine had t o continue on its previous calculation method, but to bring it together ina more standardized package. Frankly, what they call the Stables of the MIR D writers make internal dosimetry easy once I t ' s cut and dried that you don't have a n equilibrium situation. you have the parameters. s tan da r d woman. individual they were faced with. wouldn't have been indicated, I imagine they went with the standard reference man. I think the new reference man document, which Ican ' t afford, They had t o fuss with standard man numbers and stancard child and Ina therapy dose calculation, they pretty much fussed with the In diagnostics where such customized service Butit somewhat grew out of the.efforts to do internal dosimetry by MIRD tables with the older version of standard man that standard man and standard women had some dose differences in there that and finding out holes - where they arein our knowledge, and I think I will have some things to say topes, and yet they are very important for the story on uranium fuel cycle and the What I hope t o do inthe course of the book i s point out some glaring For example, there is so little work on higher specific activity uranium iso - like that.I think I can point out. I'm not so sure there is a lot I can say Many o f these aspects - big holes and things on what needs t o be done on current problems i n nuclear medicine. Th axis n ' t the purpose of the book, anyway. One o f the things 1,want very much iodo, and that didn ' tget explained in this outline as well as it r nio ht,is try to say things that need t o be done i n terms of chemical toxicolooy and ways i n

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i eh the i nternal mi ttei' toxicology e f f o r t can save the chemi cal toxi col ogi s ts alot of work. THOM9S: I think that ' s a very valuable book point because, for example, I have great difficulty finding the information I want about body clearance and deposition of a particular radionuclide. information on the chemical materials. form of miiterial . you do find some information,it was usually based on radioactive tracer exI t ' s evident because there isn ' t the Detoxication of that particular material or That was the best way t o do it. THOMAS: In that sense maybe we are ahead. a dose-response relationship, and Chemical Toxicology was a1 ways thresholdsigmoid until just very recently and now they are buying the linear and no-threshold business for carcinogenesis and mutagenesis; I think I think we were ahead i n many respects.Of course,you come t o rems o r the equivalent o f man-rem very .they are going to be into chemical STANNARD: Yes, I'm afraid SCI. Are they going to be pred THOMAS: ... .That's a useful exercise to try to help yourself balance a picture,but when it hits the headlines ofa newspaper with an evaluation o f an accident, i t ' s bad news. THOMAS: Sometimes the concentration times half - life was referred toas on internal dose. I guess Quimby really preceded Fail la in writing something They were so close i t ' shard to know who was doing John, your own career has been largely, would you call it,in radio-

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+ .Iu,bc(s : Actually, I ' d call it physics but predominately a t medically $, 'i, 1reactor fuel cycle or direct experience except a t nominal energy accelerators, cyclotron, betatrons, etc.,but with dental school, medica schools, veterinary school and several hospitals aboard the institution. I t ' s biological research institution work. Ifeel more a t home inthe1 science environment than i n any section on environmental monitoring. STANNARD: I think,ina way, I do too. I seem t o be, despite myself, getting involved i n environmental things,particularly through the NCRP work.