DICENTRIC AND TRANSLOCATION ANALYSIS FOR RETROSPECTIVE DOSE ESTIMATION IN HUMANS EXPOSED TO IONIZING-RADIATION DURING THE CHERNOBYL NUCLEAR-POWER-PLANT ACCIDENT

Chromosome analyses were carried out in peripheral blood lymphocytes obtained between September 1991 and March 1992 from 15 persons exposed to ionising radiation during the Chernobyl nuclear power plant accident. At present, an are being treated for symptoms of the delayed stage of the cutaneous radiation syndrome. Biological dose-equivalent estimates were determined, either by measuring the frequency of dicentric and ring chromosomes in first division unstable cells from conventional preparations (Qdr method), or by measuring the frequency of stable translocations using two-colour fluorescence in situ hybridisation (FISH) with composite whole chromosome-specific DNA libraries for human chromosomes 1, 4 and 12 (chromosome painting) and a degenerate alpha-satellite pancentromeric DNA probe. With both methods fairly comparable individual estimates between 1.1 and 5.8 Gy were obtained for 12 of 15 individuals. Three individuals exhibited no elevated aberration frequencies. Perspectives and limitations of chromosome painting for dose reconstruction of past radiation exposures are discussed.