SurveLllanca 22 Facilizias and ites Deriaee Tieta: 13. Dose Reassessmenc for Posulations om Asngeiaad anc ViIirix Fallowing Hxsosure is Fallous GxedL-31L-52-+2- 2 Puolicaiions 14 Sgo0e: (a) 200 ‘word Summary: Incidences of thyroid nodules, benign and maliznant, in the exposed populacions of Utirik and Rongelap have indicsatec cricical differences in corvespondence vetween nodule incidence and tnyroic dose fs che two pogulations. The estimated external dose received from the size faliout began to the time of evacuation shows that tne Rongelap sepulatiscn received an external dose ( 175 rads) which was about thirteen times tnact for the Utirik populacion (14 rads), and the thyroid dose was about ten tines larger, whereas the incidence of thyroid nodules in the two sepulations were mot signiicancly diitferenc. A preliminary study nas indicated that the critical area ci investigation that could shed Lignt is the seriod during fallouc and evacuation iar dota the islands. In addition, the face thac the Vririk population vecurned within 120 days following evacuatisa, whereas che Rongelap scoulaction returned only aice " a ps eee ce none chree vears, recuiraes that we look closely ac the Usiscik sopsulacion in terms 32 a longer exposure period, both internal and external. Further studies would, therefore, have to concencrate on the re-examination of all available data in reports issued by varicus agencies during that seriod, consultacions with sci- encific sersonnel invelved ac shac cime, idencifving the areas of uncertainszy, and using appropriate computer srograms to analyze the data. The end ule will enabie us to look for correlacions between the incidence of cthyroiid nodules and the reassessed dose estimates, lz. Relationsnis 19 Other 2Prsieccs: (a) This study will help establish dose escimates irom che time of the incident to the present, and will complemenc the aerial susvev, ior external radiation neasuremencs, over chese islands, wnich is scheduled soon. Together they should present a reliabla sicture of doses received ov the sopulations and also enadle dose astimates co be srojected ince the fucure. (6) This study will be in close conjunction with the 3NL Radiologica! Satety Program in the Marshall Islands and with related orograms of the 2NL Mecical Department. Continued collaboration with the University of Wasning=ca, Laboratory of Radiation Ecology, in the area of anvironmental radioactivit; will be maintained. . L6. Tecnnical Brozress in FY 1973: Preliminary Literature search and consultations with Dr. C. a. Sonahaus, University of California, nave been completed, This nas resulted in ceiininz areas of uncertaincy in infcrmacion and establishing the procedural steps that should be carried suc cowards elucidating this proolem. Progress is being nade Ge- 1 >/ (See Continuation Sheers) ————— — + ee ee - ee ee ��a ee ee ee ee ee oe -