Cytogenetic analysis of peripheral blood lymphocytes of occupational workers exposed to low levels of ionising radiation

The incidence of chromosomal aberrations was analysed in peripheral blood l ymphocytes of occupationally exposed people having cumulative doses of 500 mSv. The exposed individuals showed higher frequencies of dicentrics as wel l as acentrics than normal controls. Absorbed radiation dose was calculated by using in vitro dose response curve established for Cobalt-60 gamma rays . In the control constituting 17 healthy individuals, two dicentrics were d etected among 3700 metaphases analysed. In the exposed group 27 dicentrics and one centric ring was detected among 8400 metaphases analysed. Due to sm all number of dicentrics scored in each individual, the dose estimate suffe rs from a large statistical uncertainty. The collective dose was found to b e 1.89 Gy. This is in good agreement with the corrected physical doses, ass uming a mean life of 10 years for the disappearance of lymphocytes. The phy sical doses accumulated during the last 10 years of occupation were also in good agreement with the biological dose estimate. (C) 1999 Elsevier Scienc e B.V. All rights reserved.