Chromosome Aberrations Induced in Human Lymphocytes by In Vitro Acute X and Gamma Radiation

Abstract

In vitro dose-response curves are presented for unstable chromosome aberrations in human lymphocytes exposed to acute 250 kVp X rays and cobalt-60 gamma radiation. The data, fitted to the linear quadratic model, were obtained from guaranteed first division metaphases by using the FPG staining technique. The results are compared with previously published curves obtained using conventional orcein staining. Similar yield coefficients were found indicating that the earlier data had not suffered from the presence of excessive numbers of second division cells. The new data at high doses show a distribution of dicentrics slightly underdispersed when compared with Poisson. This may be explained by the distortion hypothesis. The ratios of the linear yield coefficients confirm that at low doses X rays are 2-3 times more effective than gamma rays in inducing damage in this system.