Distribution pattern and dose-response-relationship of chromosome aberrations in human lymphocytes induced in vitro by 60Co gamma-rays and 110 kV X-rays.

Peripheral blood lymphocyte culture system was used to construct reference dose-response curves for 60Co gamma-rays and 110 kV X-ray-induced chromosome aberrations at 6 dose points ranging from 0.25 to 4.0 Gy. Qualitative and quantitative differences between these two types of radiation for the yield of induced aberrations and their distribution pattern were analysed. Experimental data of aberration yields were compared after fitting them to five different dose-response models. The yields of chromosome aberrations in particular dicentrics, gave a good fit to linear-quadratic besides linear and power models. In this model, single-track events predominated over double-track events for both the qualities of radiation used. The pattern of distribution was mainly Poisson for dicentrics but gave a conflicting result for acentrics which was in excess.