Cytogenetic research after accidental radiation exposure.

Currently, chromosome aberration analysis in peripheral lymphocytes is the most sensitive method to estimate individual doses in accidental radiation exposures. The assessment of dose is particularly reliable in cases with acute, uniform, whole-body exposure or after irradiation of large parts of the body. However, the scenarios of most radiation accidents largely result in partial-body exposures or a non-uniform dose distribution. This complicates dose estimation especially in cases with protracted or fractionated exposures. Problems exist also for the dose reconstruction of radiation exposures occurring a long time before sampling. To overcome these problems, the Qdr method or the "contaminated Poisson" method can be used to determine meaningful dose estimates from data based on conventional scoring of dicentrics. Scoring of so-called stable translocations by the newly developed technique of chromosome painting should be particularly useful for estimating doses of past exposures or of dose accumulation. After incorporation of radionuclides with largely localized depositions in certain organs or tissues, realistic individual dose estimates cannot be achieved. Exemplified by incidents involving larger groups of the population such as in Chernobyl and Goiania and by single cases with serious overexposures, chromosome dosimetry is evaluated in the present article.