Dose dependent of sister chromatid exchanges in humans lymphocytes induced by in vitro alpha-particle irradiation

Exposure of human G0 lymphocytes to high-LET particles under different conditions has been seen, unlike low-LET radiations, to be substantially effective in the induction of sister chromatid exchanges (SCE). However, whereas for fast neutrons a linear dose response of SCE has been determined, there is no sign of a dose-response relationship for alpha-particles. A likely reason for this lack of dose dependence may be the irradiation procedure. Therefore, a technique developed in our laboratory to ensure uniformity of irradiation with alpha-particles was used in the present study. Monolayers of 3 h-stimulated lymphocytes were exposed with alpha-particles from 241Am. Underdispersion was found for the cell-to-cell variance of the number of SCE. The dose response of SCE was linear, with a yield of 3.4 SCE per cell and per Gray.