Cytogenetic investigation of occupationally irradiated persons a long timeafter exposure

Chromosomal analyses were performed in blood lymphocytes of 33 persons prev iously occupationally exposed to ionizing radiation. An increased frequency of chromosome aberrations, mainly dicentrics, a long time, up to 47 years after exposure, suggests that it is possible to use the method of unstable aberration analysis for assessment of previous radiation exposure. The enha nced yield of dicentrics was observed in persons who may have received irra diations above permitted limits. The aberrations represent a residue from a higher initially induced incidence. They can not be used reliably for retr ospective dosimetry but do provide a marker for old exposure. (C) 2000 Else vier Science Ltd. All rights reserved.