4 oe eevee erties Ae ge eg 25 first observed nine years after exposure among these people. By zen of Sixty-eignt, of the most heavily expcsed nad develcped nodules whi fficient concern to require exploration. Cne carcincma had been found. © of the survey early in 1969, five iscre individuals in this pepulation to have developec thyrcid masses Watch we felt should be explered. Far the more heavily expcsed group on Ponszelap atoll, i.e. several hundred 7 ancred rads estimated dose to the thyroid; and one on Utirik atoll who } sceived 30 rads. These were brought back to the U.S. for snecial study fen National Laboratory. Because of our interest in and labcratory studi 3 thyroids, the patients were brought to our institution in September, al exploration. Three of the five proved to heve lesions of the th, malignant (two Rongelap; one Utirik). One of these had extensive regi . A fourth patient possessed several nedules, one of which was very sm smpted serlous consideration that this might also be malignant. Autcorade Lavely prepared in additicn to a variety of observations commenly made m our animals (not 3H-thymidine). Several of these thyroids had many mh ilar hyperplastic lesicns, none of wnich took up significant anounts cf 2. Many of the lesions were papillary in structure and suggested papil uiticentric origin. All of these thyroids (except the woman from Uti large bizarre nuclear forms repeatedly observed under this contract in 1 humans that had received I. om was made in the past annual report cf a preliminary review of the Ma ssues for evidence of radiation effect based primarily on the bizarre n xtner subtle changes as observed in rats and human thyroid tissue. just been completed in a formal manner. Thi snellese lear 3st the validity of these criteria as evidence cf radiation effect, Dr. ard of Brockhaven National Laboratory assembled multiple sliijes of each the Marshallese, of some thyroids of Japanese atcmic bomb casualties, > the Utah-Nevada children who may have been exposed (mentioned elsewhe rort - from Dr. Marvin Rallison) and of miscellaneous unexposed nodular dliected from elsewhere in Utah. More than 100 individual slides, comp is to identity, were submitted to this writer for review and appraisal 7 radiation effect in them. All slides. were graded as to positive orn F radiation effect, and where positive, the evidence was further graded , t+, or +++; + being the slightest evidence and +++ being pronounced ey vidual slides were graded and reported to Dr. Conard, multiple slides t com the same thyroid were grouped together (still as unknowns) and 1. Although in most cases the ratings on several slides from the same were similar, it was appropriate to affix a single rating to each th was the rating changed more than one degree to arrive at a common rati 1 thyroid. The results show that all of the Marshallese except one we as having received radiation exposure. Among these was a Marshallese 2n exposed and several years later had died of other causes on Majuro a st mortem provided the tissue which was free of gross Acdularity. Sev cposed thyroids and a few of the Utah-Nevada group were graded as doubt mise of the correlation of the observations, Dr. Conard subsequently ob jual theoretical records of rad dose delivered to the thyroid (based on [body 2cmined scme days after the removal of the Marshallese people from Rong ef change attributed to radiation effect in the thyroids proved to co Most ingly precise fashion with the degree of exposure previously calculated} pldced have observers some as unese tissues were graded only + or G. Where le weight of evidence for radiation effect upon the presence of lymphocytes,