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Doses to Young Persons and Clean-Up Workers, Chernobyl

Scientists in the Radiation Epidemiology Branch (REB) have been involved in a multilateral collaboration for several years with researchers and scientists in Belarus, Ukraine, and Russia to conduct epidemiological studies of thyroid diseases and leukemia among the populations affected by the 1986 Chernobyl accident in Ukraine. The task of the REB dosimetrists is to estimate the radiation doses, and their uncertainties, for all individuals involved in these epidemiological studies. This includes:

  • About 25,000 Belarusian and Ukrainian individuals who were children at the time of the accident. A possible association between thyroid dose and thyroid cancer is investigated for those subjects. The thyroid dose results essentially from the consumption of cow’s milk contaminated with Iodine-131. Thyroid dose estimates are derived from thyroid scans, which were performed on all cohort members, and from answers to personal interviews to obtain information on their residential histories and dietary habits;
  • About 2,500 Ukrainians who were in utero at the time of the accident. Here again, thyroid cancer is the disease under investigation. The estimation of the thyroid doses for the subjects is based on the assessment of: (1) the intake of Iodine-131 by the mother, essentially via the consumption of cow’s milk; and (2) the transfer of the Iodine-131 to the embryo or fetus;
  • About 1,000 Ukrainian workers, who were involved in the mitigation of the accident at the Chernobyl site or in its vicinity and who were included in the case-control study of leukemia. The radiation exposures of these workers were mainly due to external irradiation from fallout deposited on the ground and building materials. Individual bone-marrow doses need to be estimated, as leukemia is the disease of interest. The bone-marrow doses are derived from the assessment of the whereabouts of the clean-up workers and of the radiation fields during their missions at the Chernobyl site or its vicinity. Red bone marrow doses for clean-up workers were calculated with the help of the RADRUE system (PDF, 358KB).

For more information, contact Steven Simon.