THYROID NODULARITY AMONG CHERNOBYL CLEAN-UP WORKERS FROM LITHUANIA A.Z. KESMINIENE, J. RIMDEDCA, Z.VILKELIENE XA9745455 Lithuanian Chernobyl Medical Centre, Vilnius, Lithuania

The accident at the Chernobyl NPP on 26 April 1986 was the worst in the history of nuclear power. This catastrophe resulted in massive contamination of the area necessitating evacuation of the population, an extensive clean-up and construction of sarcophagus. This clean-up and construction activity was accomplished by approximately 600000 workers from former Soviet Union. Exposures were from rapidly-decaying radioactive iodines, as well as from Cs and other long-lived radioisotopes [1]. Because the thyroid gland is highly susceptible to the carcinogenic actions of radiation, especially when exposure occurs at a young age, a clinical examination survey was conducted to determine the prevalence of thyroid abnormalities among former clean-up workers [2]. Nodules are considered a sensitive for evidence of low-dose radiation effects [3]. Presence of benign tumors has been linked with development of thyroid cancer [4]. A remakable increase in thyroid cancer has been reported among children living in contaminated areas around Chernobyl [5]. The objective of this study is to evaluate the dose effects of chronic radiation exposure (mainly from external gamma radiation, but residual I 31 might also have been contributed to the thyroid dose among those sent to Chernobyl within one month after the accident), prolongation of time in zone and length of time after expdsure role in developing thyroid tumors within a study population.