Chromosome Aberrations in Persons Accidentally Exposed to 192Ir Gamma-Rays

Chromosome examinations were made both in cultured peripheral lyniphocytes and in freshly aspirated bone marrow cells of 6 persons accidentally exposed to gamma rays from /sup 192/Ir. Samples of peripheral blood for the chromosome analysis were repeated mostly at weekly intervals during the hospitalization beginning 10 to 11 days after the initial exposure, and at more prolonged intervals after that period. The average yield of dicentrics plus rings in peripheral lymphocytes ranged from 0.0015 to 0.1367 per cell. The chromosome abnormalities, mostly of the stable-type rearrangements of chromosomes, were observed in bone marrow from two of the 6 cases. Based on the aberration yield in peripheral lymphocytes, the average total body absorbed dose was estimated to be equivalent to 9.8 to 124 rad of /sup 60/Co gamma rays and 15.6 to 152 rad oi high energy x-rays. When the dose estimate was made with the Q/sub dr/ value, the average total body absorbed doses were higher than those obtained by direct extrapolation of the aberration yield. This seemed to resuit from non-uniformity of the exposure. (auth)