Appendix 24, U.s. Tri-Partite Conference on Permissible Dose (March 30, 31 & April 1, 1953)

Page 1

Arden House, Harrimanm Nm York March 30,'31m and April 1. 1953 hr mls sib le Dosagrr from Ex tern1 Radlation Sources: A. General prlnclples o f drternlnlng pe mls tib l elin its 1. Units and deflnltions a. Mmsses of organs 3. W l fl cation r of pernisslble dose due t o b. Limited rrglons o f body 4. Relatlve blologlcal effect for various radlations and tls sues 5. Wi flu t lons of pemlssiblc dose due t o genetic considerations 6. Modi flu t lons of pe mls s lb lr dose due t o population consideratlons 6. Speclflc consideratlons and recanandations 1. Gallma radiation and X-ray 2. Neutrons o f varylng entrgler 3. Beta radfatlon and electron beams 4. Heavy part l cles Permissible Dosages from Internal Radiatlon Sources: Units and deflnitfons Special problems presented by internally originated radiatlon Factors i n tissue localizatlon o f radloactlvc materials Factors influencing elimination o f such materials Particulates i n respiratory tract

Page 2

7 . Pennissible ll m its for life fonns other than man 8. Specific consfderatlons and recumendations of penis sfb le dosages 3. Ac ti n l um 6. Other alpha emitters A. General Droblms o f dosimetry 6. Spedal technical conslderatfons I n radiation measursncnt 1. Accidental o r emergency. with special reference to cl vil defense

Page 3

Tri part lte Conference on Pennlssible Doses Arden House, Harriman. New York March 30. 31, and April 1, 1953 Giuscchino Fail la John F. Lout it Will lan G. Marley Dr. Bugher convened the first session of th Tri part lte Conference; wclcoated the delegates; oriented the assembly M the topics approved f o r discussion, the sccurlty methods under which the conference was t o p r o c c e the clearance of news releases, and other various Introductory topics; and then introduced thc chairnun for the first day - Or. Mitchel4. Dr. Mitchell accepted the chair. extended greetings. and proceeded wlth the items on the agenda. I. PERMISSIBLE DOSAGES FRW EXTERNAL RADIATION SOURCES A. General Prlnclples o f Determlnlng Pernisslble Limlts Dr. Fatlla presented a definition of "permissible dose" as king "a dose of ion l ring radlatlon that i n the light of present knowledge i s not expected t o cause appreciable bodlly injury to tha average person a t any tlme during his llfetiae". As used I n the definition, "appreciable bodily fnjury" means any bodily injury or effect which the average person would regard as being objectionable and/or canpctcnt medical authorities would regard as being deleterious t o the health and well-being o f tht The questlon arose as t o the use o f the tern "average person". and Dr.Fall la explained that It was used ln an effort to exclude persons who claim t o be extremely sensitive or susceptible tu however, decided in this regard that whatever def ln it lon was accepted by this group would be regarded as having the equlvrlent force t o law, and that any legal hassle which arose would be settled on thc basls o f what t s technically reasonable. A discussion also arose a t this point with respect t o the unit of measurement to k used. painted out that the International Congress o f Radlology recDannded the use o f "ergs per gram" I n expressing doses o f lonizlng radiation. Or.Fall la said he would prefer t o use the "rep" In this case, because It seem to better represent what i s being talked about and better connote lOn lZl ng number o f ergs per gram from 93 t o 100. The question here before the house, however, i s t o decide whether a special unlt should be used for all ionizing radiation o r whether the ergs per gram tern Another question arose as t o the possible medical o r legal reactions t o the deflnitlon. tie also stated that he was submitting f o r national congress consideration a Change f n the

Page 4

Dr. Lauriston Taylor then stated his understandlq of Or.Fall la ' s proposal as not suggesting the elimination d the con up t 'ergs per gram* but rather suggesting the use ofa multiple OF aunit of t h a t far the sake of COfIVenfeWk He suggested that the problm, therefore, wls t o agree on tha multiple or a lwly for lt...a rum for one erg per gram, perhaps the nmkr 100 because It I s close to a and that Or. Fail la ' s definition for pcrnissible dose was excellent. The CMsensUs Of opinlon o f the group was that the t e r n "average men" was clearly understandable, Mr. Binks, when asked t o dtscuss the new factor o f "W', said I t appeared t o have an enrrgy value dose" or 'pcm!rsible aose'. After a pro and con ciscussion. Or. Bugher said he believed there was impiied i n the det in it lon the ldea that it IS a inaxiimun value; also there was the impllcation that as f a r as w n a b l c and practical the actual exposure being maintained be as low as feasible. It was finally agreed that the tern t o be used w l dml t the word "mxlmum"and merely read 'pemissible As f o r a choice betwaen the use o f the term 'ergs p e r gram'' or "rep', there was considerable discussion as t o the dist ln ct lon between the two, so further discussion on the subject was deferred until a l l the delegates might road and informally discuss the recamendation. It was then suggested that when the alnutes of t h i s meting w r e produced, the over-all report should bear its appropriate class l fl crt ion and each individual section should also bear its OWI rrturlty classification in order that unclassified portions might be discussed with uncleared parsons. a. The f l r s t ttem under t h i s topic was "masses of organs*. Dr. WIrren made the ruggestlon that it afght k well to state as a general principle that ifa value i s conrnonly utilized ad then i s no very strong reason f o r changing It, i t would be best t o allow It t o rumin. Dr. Mitchell rqrrrd wlth Or. Mrren, and proposed that the discussion under this toplc be lim f ted to any proposed changes i n the previously accepted Chalk Rfver valuer. These organs for which changes were suggested were: (1) T roid: The first Item to arise dealt with the value t o be given the thyroid. The avrraga mss another. 20 gruns was the Cahlk River value, and the suggested new value 1s 15. The Brf tls h still use rrld he could not rely on his autopsy evidence; i t would be heruler because a der of patients had a mild degree o f endemic goiter. At this point, Or. Bugher coraunted that the standard man is a fic tl - tious entity MICh f s valuable as a constant basis of reference, and 8ny change trim the fi guns which have been used should be contemplated only w i t h considerable reluctance and on the barfs of m a l urgency because the constancy o f these figures f s where the value lies, It wls agreed, therefore, that there would be no change fran the 20 grams figure accepted a t Chalk Rlver for thyroid. (11) Adrenal$: The presently accepted value f o r the adrenals i s 20. The suggestion was nada that the figure m & dto 14. based on a review of literature at the Argonne National Laboratory and Investigators' values ranging fran 6to 12. Dr. WIrren pointed out that most of the flgures ob taf nd wtu based on a u t o p ~ ydeterninations - deteminatlonr that have k c n made on adrenal organs which hrve been depleted due t o an acute or wasting diserro and therefore are not truly representative o f thr norully larger sized adnnals. Ha therefore suggested the retentlon o f the Chalk River value of 20. (111) Blood: Dr. Warren suggested a change i n the t o t a l mass of the blood fra 5000 grams t o 5440 grams, based one fact that more accurate methods of detennining total blood vlune have been achieved since the Chalk River conference. Although It was believed that the figure of 5400 was good, it was agread t h a t the matter should be referred for further evidence t o be brought fomard a t the Copenhagen con- (iv) Gastro-intestinal tract: The flrst question t o be raised on this subject was whether or not the weight proposed Included content. Dr. Warren said i t was the substance of the walls and d i d not Include At this point the recarnmdrtion was again made that i f any of these items discussed at this conference were forwarded t o the Copenhagen conference they be coupled with are Cm nd atl On that as f a r as possible exlstlng values be retained unless there were strong medical evidence t o the contrary. o f thP-s organ varies considerably fran country t o country bs well as fra one part of a country to 25 I s the nom1 ffgure used i n the eastern seaboard regions o f the United States. Dr. Urren

Page 5

AS fm 8 proposed chrnge i n the figure for the G.I. tract frar 2000 grus to 2300 grim, Dr. Warren polntcrd out that then Isa great deal of varlatlon i n thc experinntal values obtrlned accordlng to the utlng and bowel hr b lts of the indlvidurl; also, thee wld be appreciable altarations I n tha wall thlcknrss and I n the mass of the connoctlve and supporting tissue. He w u l d hesitate making a charge I n the present figure becIUSI, although If one went Over several thousand autopsies OM might find a slight shift me wry or the other, wlthln the terms of the standard w n these s hlf tr would not be slgnlflcant. The value f o r the 6.1. tract, therefore, -ins unchanged. t h l s frun inc1ud.d o t h e tissues and oqans not seprrately defined. Dr. No an sald that the only occarIon for dtnga flgure far fat would be I n the de tr ral nrt lon @+ ,ewnlr ~ ble body burden far Carw a It t o Dr. Morgan far subnrssim to the Copenhagen conference. ( v i ) Red Marrow: Or. Ylrren sald he was tn pm lab on tory th t the gnat diff l cult y Is that even In relatively dense hanatopoietlc areas there Is a very apprrclable mixture of fat. It was ag red that the present value for fat would be retained, and that Or. Yarron would sumit new evldence on the subject at a later date. Allof the figures here discussed are based on aSt8ndird man wlth total body weight o f 70 kilob. Or. Worgan opened discusslon on the second ita under the topic 'The Strndrrd k n ' - c h n l c a l ca position - by st rtl ng that hlr values for the avenge cham l ul congoritlons mnly a listing of the Chalk RIvrr values, and that although efforts were belng made to g e t better data on the e l m t in v ov ldIn th ls problrn an (1) to get acceptable sverrge values for the tot81 body, and ?2) to get the but rvrrage value for each organ for use I n the calculation of the dirt rl but ion of radlolsotopes I n the body organs under eq ulli br lu conditlonr. unexposed subjects which gave a body radloactlvlty CorrospOndIng to a potasslrr content o f about 0.2S prallnlnary work resulted i n valuer o f around 0.2% for pot rrs lu content. It ws, therefore, suggested that 0.2% be adopted as a provisional value for pot as slu content untll such tlrw as better Info mt lon I s available, because it was felt that thls value i s Important from the point of view of detetmlnlng the natural background o f the body. Stnce allof the values are pf wis l mal and h8ve a posslble e m o f 25 t o 501, thr proposal agreed upon by the conference ms that the value be changed t o 0.2% Or. Marlnelll: then suggested a sodium value nfght be of importance In est imt lng exposure over a long tlme. Or. Morgan sald that a nunbcr o f values we nw Mbh to better calculatlon, and that hls subcannittee would welcaw any evldence. The present value for sodlun was unchanged. troll normal hmns, fraa which It appears there are important mounts o f boron I n the lens o f thr hunn eye. The Brit l sh doc uv nt on this work was handed over t o Or. Morgan, with the remark that further de tall s would be published. Fat: A value o f 3goO YIS proposed for fat; I n Chalk Rlver It uas defined as 8390 grams, but colpletely dlssatlsfled With the ur sur arn ts he has a t - Or. nltche11 then mentimed SOW work done by the British with pok sri u measurements on 20 or 30 O r . l4ltcholl then asked Or. Mor an t o speak on neutron activation analysls. O r , Mo an said th& neutron actlvatlon analysis was stil ? Ina prellmlnary Swge, but that they have found re7a t lv ely large Mounts o f alrninun In the llver, cadnim i n the kldney, sill con and copper I n the intestine, and copper, sllicon, nickel, aluninun, boron, etc., In the hrrrt. Hmever, there Is still insufficient evidence available t o k sure that t h l s represents the standard nun, and further evidence must be obtalnad before any r pec l fic recanandations can be made. 3, Modlflcatlon of Pc mirs lb le Dose a. The first portion of this discusslon dealt wlth the modlficatlon of permissible dose due Or. F a i l l a ' s subcamittee accepted the recannendatlon whlch distlnguished between two age t o the various factors o f age. groups - one under 45 and the other over 45. For the over-45 age group, the p a l r I s s l b l e dose was accepted as double the pennlsslble dose for the under-45 age group. Another recamendrtion Wls that the weekly dose rate for chlldren k 1/10 of tho pennltslble ll rn lt for occupational exposure. t h a t o f going back t o the orlglnal permissible dose level …