[The retrospective cytogenetic dosimetry using the results of conventional chromosomal analysis in Chernobyl clean-up...

The paper presents the results of the cohortal biodosimetry carried out in 435 Chernobyl clean-up workers, who were surveyed with the conventional cytogenetic technique in terms from several days to 10 years after the end of their duties in the Chernobyl accident exclusive zone. An empirical model of the aberrant cell dynamics was utilized for the calculation of mean initial yields of dicentrics and centric rings in groups with different terms and duration of staying in the Chernobyl zone. Corresponding protracted irradiation doses estimated from aberration levels ranged from 79 to 670 mGy. The probabilistic distribution of the radiation doses was constructed by the applying the Bayesian analysis to initial individual chromosome exchange yields extrapolated to the exposure termination moment. This distribution was characterized by the mean dose about 460 mGy and maximum of probability density in the interval of 50-300 mGy. For the late somatic risk assessment in clean-up workers the probabilistic distribution of equivalentally-acute radiation doses was proposed; that had the mean value about 270 mGy, modal classes of 250-350 mGy and 99.8% of the probability density concentrated within the dose range from 0 to 1000 mGy.