Distribution of childhood thyroid dose among cohort members for epidemiological health study in the Bryansk region

摘要

With the aim of carrying out a long-term medical follow-up with radiation dose reconstruction, a cohort of subjects was selected among inhabitants of the most contaminated area in Russia following the Chernobyl accident (the western districts of Bryansk region). The cohort is comprised of 1065 subjects who were under 10 years old at the time of the accident, Most of them were examined on health status in the Chernobyl Sasakawa Health and Medical Cooperation Project, Since the main findings of studies in the project were thyroid abnormalities, selection of subjects was conducted on the basis of the plausible estimates of radiation dose to the thyroid, To estimate thyroid doses, the data from direct measurements of ~(131)I in the thyroid and questionnaire data on individual dietary habits in May 1986 were used. Reasonable approximations were applied to reconstruct individual doses from available data, including doses for those persons who had not been measured for thyroidal radioiodine. The distribution ofinternal radiation dose to the thyroid among cohort members was obtained. The individual doses to particular subjects are estimated with inevitably essential degree of uncertainty, However, the distribution of subjects into wide dose intervals, from under 200 mGy to over 2 Gy, seems to be an acceptable approach for cohort study in radiation epidemiology.