UNCERTAINTIES IN RADIATION DOSES FOR A CASE-CONTROL STUDY OF THYROID CANCER AMONG PERSONS EXPOSED IN CHILDHOOD TO (131)I FROM CHERNOBYL FALLOUT

Uncertainties in thyroid doses due to iodine-131 ((131)I) intake were evaluated for 2,239 subjects of a case-control study of thyroid cancer following exposure to Chernobyl fallout during childhood and adolescence carried out in contaminated regions of Belarus and Russia. Using new methodological developments that became available recently, a Monte-Carlo simulation procedure was applied to calculate 1,000 alternative vectors of thyroid doses due to (131)I intake for the study population of 2,239 subjects accounting for sources of shared and unshared errors. An overall arithmetic mean of the stochastic thyroid doses in the study was estimated to be 0.43 Gy and median dose – 0.16 Gy. The arithmetic mean and median of deterministic doses estimated previously for 1,615 from 2,239 study subjects were 0.48 Gy and 0.20 Gy, respectively. The geometric standard deviation of individual stochastic doses varied from 1.59 to 3.61 with an arithmetic mean of 1.94 and a geometric mean of 1.89 over all subjects of the study. These multiple sets of thyroid doses will be used to update radiation-related thyroid cancer risks in the study population exposed to (131)I after the Chernobyl accident.