(137)CESIUM-INDUCED CHROMOSOME-ABERRATIONS ANALYZED BY FLUORESCENCE-IN-SITU-HYBRIDIZATION - 8 YEARS FOLLOW-UP OF THE GOIANIA RADIATION ACCIDENT VICTIMS

The radiation accident in focus here occurred in a section of Goiania (Brazil) where more than a hundred individuals were contaminated with (137)Cesium on September 1987. In order to estimate the absorbed radia tion doses, initial frequencies of dicentrics and rings were determine d in 129 victims [A.T. Ramalho, PhD Thesis, Subsidies a tecnica de dos imetria citogenetica gerados a partir da analise de resultados obtidos com o acidente radiologico de Goiania, Universidade Federal do Rio de Janeiro, Rio de Janeiro, Brazil, 1992]. We have followed some of thes e victims cytogenetically over the years seeking for parameters that c ould be used as basis for retrospective radiation dosimetry. Our data on translocation frequencies obtained by fluorescence in situ hybridiz ation (FISH) could be directly compared to the baseline frequencies of dicentrics available for those same victims. Our results provided val uable information on how precise these estimates are. The frequencies of translocations observed years after the radiation exposure were two to three times lower than the initial dicentrics frequencies, the dif ferences being larger at higher doses (> 1 Gy). The accuracy of such d ose estimates might be increased by scoring sufficient amount of cells . However, factors such as the persistence of translocation carrying l ymphocytes, translocation levels not proportional to chromosome size, and inter-individual variation reduce the precision of these estimates . (C) 1998 Elsevier Science B.V. All rights reserved.