HUMAN POSTMORTEM THYROID I-131 CONTENT AND RISK ESTIMATES IN BRATISLAVA, CZECHOSLOVAKIA FOLLOWING THE CHERNOBYL ACCIDENT

From 3 May to 4 August 1986, thyroids of 416 postmortem subjects in Bratislava (population: approximately 400,000) were measured for I-131. Subsequently, dose rates in this organ for the day of exitus were calculated. Mean dose commitments were estimated by integrating linear or quadratic-periodic regression lines drawn through scatterplots of logarithmically transformed daily dose rates. The mean dose-commitment estimates in thyroids of adults were 0.74 and 0.58 mGy for linear and quadratic-periodic regression, respectively. The same for thyroids obtained from donors of fetal to 18 y of age were 1.67 and 1.77 mGy for linear and quadratic-periodic regression, respectively. A comparison of the actual thyroid radiation burden with its theoretical values calculated in the first days of contamination of the environment showed that the models used were safe enough to protect the population. Estimates of absolute risk for thyroid cancer showed that excess incidence that could be expected as a result of the Chernobyl accident shall remain obscured by the "spontaneous" incidence of this disease at geographic localization.