Analysis of absorbed doses by the thyroid gland  (TG) of residents of the regions of Belarus affected by the Chernobyl accident showed that the highest doses absorbed by this organ  (600-700 mGy) were received by infants and children, who in April 1986 were in the age from 0 to 4 years old. These doses did not differ much between men and women. The curve of  absorbed dose values ​​versus age is described well by the exponential dependence. The incidence of thyroid cancer (TC) in age groups of both sexes (from 0 to 19 years), depending on the absorbed dose by the TG, was characterized by a linear relationship with a coefficient of determination equal to 0.89. Persons from the younger age group (0-4 years), who received the highest absorbed doses, had a higher morbidity. Persons from the age group of 15-18 years old at the time of an accident received lower doses by their TG and demonstrated lower incidence of TC. Extrapolation of the direct dependence of the latent period of cancer on the received absorbed dose in those age groups suggests that the shortened latent period of this disease recorded in Belarus may be associated with the formation of very high doses absorbed by TG (more than 1.2 Gy) in some children from affected areas.

 

Keywords: I-131, Chernobyl accident, Thyroid cancer, Absorbed dose

 

Abreviations: TG – Thyroid gland, TC – Thyroid