- : Nae bee uh a te, ce a . ; : cee he bee SReat ab BEBM ate wal ARMLEee eth GWAMOA entedAD, sReRe Feot oat 334 . . . STANNARD pelipliecai oload. Aii OF tne 5U Lhorotras: patients examined show‘ed abbe rations while none were seen in the control eases, Also a dose-cffect rete iaestig fi ta be nonlin car butin ams overt ring with body burden or calewigs see a? appear po:sable to deriive, Vhe aberrations were largely breaks ($-80 pee bur olen scored eclish and dicentiic chromosomes but not deletions or rings. The rat eo: ship between these findings and vancer incidenceis, of course, stili in the spec tative siace. It segras unlikely at the present junczure that the maramoth scien od technical problems in the :horotrast patients will be solved in time to meu 21s group a5 quantitatively sansfying as some of the others but ifs hop. d- Wak te effort will continue nevertheless. 1 va Plutasice.—There are no recorced incidents of cancer in mau frosts. oey tion of ay plutoniumisotope, although there have been some deros vers or the worker population (74, 75). This reflects largely the effectiveness of carina measures and perhapsalso the relatively short time during which these ‘pv burdens have been extant. Nevertheless, because of the importance ef pluto: to the nuclear energy industry, full-scale animal studies have been une. aay since the early 1940s and have expanded considerably since the early and mid1$50s. Also there are metabolic data in man extending over manvyears. These have been reviewed, recalculated, and reinterpreted (76). During the period of this review several milestones have been passed tn the animal verk. Dougherty & Mays (77) and Mays et al (4), repert that the chief cause of death in their large beagle colony exposed to one of several bene- seeking radionuclides, 7**Ra, 73°Pu, 7#8Ra (mesothorium), 72®Th, and ?°Sr is bone cancer. With 739Pu. death with osteosarcoma 8 vears afer injection of Ee plutonium appears to be about 6 times as likely (on an activity basis) as for 225a_ This high relative effectiveness is exceeded only by that for 77" Th. The most recent data (78, 79) reconfirm this finding, and all studies reiterate in the dog the earliest suggestion of such a difference in toxicity betucen nitonium and radium made onthe basis of work with rodents (80, 81). This erpirizal toxicity ratio has figured stronglyin the setting of maximum allowable exposures to plutonium (75, 82). hegrebi 7 cit oO The possible mechanismsfor this difference have now beenall but settled as Rerte ibrar cd sae : sys : + = FA residing in the modeof deposition of the nuclides in bone (4. 77, §1, 83, and maa. ben clpecath mage “rath“4 after a short period of surface attachment, exchanges with calcium and depo:+ more or less throughout bone mineral (although still not un/forrily> Tris has led manyto refer to plutonium as a“ surface seeker” and toradium as a" sc’ume seeker.” Tete ty a ae others). Plutonium deposits and remains on bone surraces. wherers radi nn Ch W , 4 There are other differences. Plutoniumde pusiis in soft lisste, wine sina hia 4 well _ oh sed oy gid ea nh iy trausiently, to a much ereaier extent than redhurm wand timers of sate te er liver, are nowappearing in animals carrying long-rcrm devasis oo citer ae : ” ~ sok (7). Bile duct and other lestuns nave also appeared. This nas led Mays (84) 53 calculate the relative risk to bone versus liver cancer with parenteralis iniected ad ak 74 4 re ¥t figh f nf ar . seo tere 1 rete + comity oe ayer “TET RPT ROCKETTe ee Ad Afreng-ah yee bahia.ceveabebige:ee yO} Ge ha ~ 710 ROR ef bevvlna papucentpe ra8 ys WEake eae Pee . hte eM tL atadea te the deena dah tp apepen tswh swatpy eteOatesaepaige Behee bs ie ehhnae ep ‘a -, Ale we tS as ; venye . “3 ver, s , wie tee Paw ge vee eget re. ppt Re doe eos ae A ped Hoot Gattiet a A eet pends wainis te8, veagsie in deen coteae wowa ates : os Ma te ah Fem even ge pea.Oe ay tee tae agua ‘me eg cante “ ee . Big oe ap ay swatsndetaped. “ee hebte Na sree