Ultrasound-detected thyroid nodule prevalence and radiation dose from fallout.

Settlements near the Semipalatinsk Test Site (SNTS) in northeastern Kazakhstan were exposed to radioactive fallout during 1949-1962. Thyroid disease prevalence among 2994 residents of eight villages was ascertained by ultrasound screening. Malignancy was determined by cytopathology. Individual thyroid doses from external and internal radiation sources were reconstructed from fallout deposition patterns, residential histories and diet, including childhood milk consumption. Point estimates of individual external and internal dose averaged 0.04 Gy (range 0-0.65) and 0.31 Gy (0-9.6), respectively, with a Pearson correlation coefficient of 0.46. Ultrasound-detected thyroid nodule prevalence was 18% and 39% among males and females, respectively. It was significantly and independently associated with both external and internal dose, the main study finding. The estimated relative biological effectiveness of internal compared to external radiation dose was 0.33, with 95% confidence bounds of 0.09-3.11. Prevalence of papillary cancer was 0.9% and was not significantly associated with radiation dose. In terms of excess relative risk per unit dose, our dose-response findings for nodule prevalence are comparable to those from populations exposed to medical X rays and to acute radiation from the Hiroshima and Nagasaki atomic bombings.

[Characteristics and results of the determination of the doses of internal irradiation of the thyroid gland in the population of contaminated districts of the Byelorussian Republic]. / Osobennosti i rezul'taty opredeleniia doz vnutrennego oblucheniia shchitovidnoi zhelezy dlia naseleniia zagriaznennykh raionov Respubliki Belarus'.

The authors provide the results of studying the reconstruction of individual doses of thyroid radiation among the community living in polluted areas of the Byelorussian Republic according to radiation monitoring data and with regard to the nature of radioactive pollution of the land. Every individual result of estimating the degree of thyroid radiation was characterized by 3 magnitudes: the lower and upper limit of possible values and by the intermediate (basic) value. The authors hold that studies of the correlations between the values of individual doses of thyroid radiation and different parameters of the radiation situation in every region will promote further specification of individual doses of thyroid radiation.

[Characterization of irradiation levels of the population in the controlled areas 4 years after the Chernobyl AES accident]. / Kharakteristika urovnei oblucheniia naseleniia kontroliruemykh raionov za 4 goda posle avarii na Chernobyl'skoi AES.

Based on a summary of the radiation and hygienic control data, the authors suggest empiric mathematic models depicting the dynamics of the formation of external and internal radiation doses within the first 4 years after the Chernobyl NPP accident. It has been established that in the areas of rigid control, the mean radiation dose amounted, within the period indicated, to 3.5 kev, that due to external radiation to 2.67 kev; the collective dose for 273,00 population living in those areas constituted 9.6 kev.

[A radiation criterion of permissible living of the population in polluted areas]. / Radiatsionnyi kriterii dopustimogo prozhivaniia naseleniia na zagriaznennykh territoriiakh.

The authors review approaches to the basing of the "life dose" standardization as a criterion for "intervention" into the rehabilitation period after the disaster and the numerical value of that standard equal to 350 mev for 70 years. Relate principles that underlie the models of predicting estimated doses of external and internal radiation. The total estimated life dose is computed in accordance with the following formula: D(70)3 = 21 (4.5 x 10(-3) qm + 1) + 0.87 X 10(-4) sigma, mev, where qm is 90% quantile of the content of 137Cs in milk, Bq/l; sigma is density of area pollution, Bq/m2. The predicting model enables estimating the individual dose of the critical population group radiation. However, it cannot be employed for assessing the expected collective risk, the long-term somatic and genetic sequelae.