ee 4 lu? ‘ae LARSEN ct al. TAEA SM 224/007 ouly two subjects, both about one year ol age af exposuie, have beew lound to have prunary hy polhytutdion Phe wcccnt avadlabitity of suphisticaled tmiaaunoussay dechamgues bor thytoame (14) aod thyrotropin (TSH) has allowed more thorough Gayton evaluation of the eaposcd population who do not Nave knowa ihyroid abnodmalitics (43 Roigelap people) 103 superficial wad healed wethin several weeks wilh nodal regrowth of lai Shehet scaling fenilaed mi sume cases but tho development of shin malignancy las been voted a subsequent years Another source of exposure ib ddl the istan liitially, prophylecta Ty was dacantinued tur two months ina sample group of exposed Eroups came (rom udcrnab absorption of rudignuchdes from mbadatan and, subjects and VU U ot bovine TSH were given intranmuaculaly. Plasues 14 wos ascusuicd beluse ligestiun vi conlanvnaled food aad water Radtodeaucal winalyses fun during did 24 tours adder PSE the tis few weeks showed the following estimated body burdests (ui) ol the dhe mean increment in Ty was 2 4021.2 pg/di (racan £ SI) in the caposed group, sigiulic antly less than the value of 4 2200.3 py/dbia conmbiols. ‘Thus suggested a decieuae wn (hyduid teserve in capuscd subjects Accordingly, prophylacte 14 tieatinent was dincoutiiued Jos two tmunths, and basal plasma Sy and TSE, as well as the memeat in ‘ESI altea Shysutiupin Releasing Husmene CT RID) was measured Phe upper hit of the moral plincipal padionuchdes i the Rongelop population af one day post exposure mS bo 22) ba O $4 27, care cutth group Ob 2) "44 Gin thyroid gland) 04 112, Ru GOLA, PCO OOFS, and tissile aistemal O 0 O16 (uy) Lusaf plasma PSH was 3 U/ml aod of the TREH-induced TSH response was 22 pUsaal an No acule syanptoms were dotcd tron this iiterdab absor plow of rddignuchiues, control Marshallese subjects, Four of 43 Rongelapese had abnormally bigh basal TSU and and by six months urmalyses indicated they were vitally completely climinated PROB induced (SH iclease on two such tests as opposed to only two of 214 contrals Nevertheless, the cadly exposure lo radtotodines resullcd io seqious myury do the ‘Ty concentrations were low, of low normalin these uidividuals tas Phese resulis indicate the presence of cutly thyroid dyslunction. Several other subjects have shown al least vac abnomal finding Dut have wut had the sequued suuvbes of fests tu ince! the estabilisiied CHigéia fo dhied quasicds of these sulyects (he estimated Eyrond exposure dose was ~ 400 rads Hypothyroid has been previously noted wfter therapeutic duses uf '9't for hyperthysuadiom, but nut io individuals exposed Jo the relatively low levels of thyronlad radiation (< 400 rads} collimated for these indaviduals, (hyroid glands with date clfecds to be descnibed below. The thyroid dase was estimaicd to be considerably ligter ie the childsen becuuse of the smaller stze ul the thyruid glands. In the Rongelap peuple the thyroid dose tious Baim radiavien and radtoiodies €pracipally 2b, 71, 4b and 8) was estunated to be about 335 cads ia tie adults whereas mn sinall childien the doses cunged up to 700 1400cads Phe thyroid doses mi the Aifingnac and Utiikh groups were extrapolated trom the Rongelap estanates assuming the ralia ob whole badly ganna and todine doses were the same as i the Rongelap people Following the initial studies, anual examinations and, wore recently, BACKGROUND quarterly exumingtions of the exposed people, a wellus an unexposed coutial This tepoil concerns late radiation elfeets on the Uhyroid ina population in Whe Marshall Islands tnadvertently expused to fallboul. The accident occured on 1 March 1954, during the United States atumic testing programaie when an unexpected shift ol wieds, following detonation of a thermonuclear device al Bikint, caused radioactive Lallhoud do be deposited on several inhabited islands fo the cast Evacuation of exposed persons was accomplished by two days. The hollowing were cslimaled whole body ganna duses im the Marshallese on three alolis. Rongelap (64 people), 175 rads, Ailingnae (18 people), 69 rads, and Utuik (158 people), 14 cads (Phere were also 28 American servicemen on the island of Rongesth who received abuul the sane exposure as Ue Ailiagiae group.) Acule cllects of gamuna exposure were noted io the Kongelap and Aulingnae gioups, but notin the Ulirtk group “These consisted of eaily, dransient anorexia, hatieca dead vomntinag ina number of peaple follawed by depression of white bioud cells and platelets to about half nuemal levels Fortunately the hacmatoulogical depression Was Nol great cnough to pesult in delectable cluwtcal signs of infechou or bleeding No specitic Uierapy was necessary and no dealtis occurred, and bloud cells rebated ty uea normal levels by one year. Un addition, on the Rongelup and Aibngnae groups, beginning about two weeks post expusure, hadiation bars CbcGe butts) aid spotty epilation of the tead developed where Fallot nioteidab dad bee deposited on the sha hese burs weie hitgely Marshallese population, have been carted out, and tesults of these exaniinalions have been pubhisticd [1 4] Inthe Host ten years alter Che accident lew tidings were noted that could be related tu radiation exposure. An increase Wi dniscai pages and stulbittis the exposed Rongeclap women was bought to be possibly related to exposure During the second decade, however, serious late effects develuped related pranasily to the thyroid gland fn addition a Rongelap man who had been exposed at one year of age, died of acute myelogenous leukacniia which was likely iedated to padiation exposure [3] Betore thyroid abourmalities became apparent, was aoted that about five clhuktien exposed al fess than five yours of age showed some degree ol growth Telasdation (4) in dwo boys growth aetardation was murked and frank ay xocdema developed. “Vhyrord hy poluoction iclated (ou thyroid mjury later became apparent with imore sophisticated techniques tor deleomiiuig thyruxine levels. Tt was nul detected caly ui the childien By PRE determinations because of masking of tue ihyroatme levels by wuusuaidly hugh devels of dodoprutein, later tound do be characteristic of the Marshallese peopte [5] Nodules of the thytoid gland begun to appear Rongelap children and to 4 tesser exiend in adulls beginning about wine years post caposue These nudules lave comtinued to appear over the subsequent )5 years, aud vitually allot these