Results of a cytogenetic follow-up study 7.5 years after Cs-137 exposure at the Goiania (Brazil) radiological accident

Ten persons exposed to Cs-137 during the radiological accident in Goiania (Brazil) were re-examined for the frequency of unstable chromosomal aberrations (dicentric chromosomes, centric rings and acentric fragments) 7.5 years after the first examination. It was found that the frequencies fell to about 5% of the initial values, for those individuals who had been exposed to moderate to high doses. For the subjects exposed to low doses, of the order of 0.2 Gy or less, the observed frequencies of chromosomal aberrations fell much more slowly.