The influence of anoxia or oxygenation on the induction of chromosome aberrations in human lymphocytes by 15-MeV neutrons.

Dicentric and total aberration yields induced in human lymphocytes by 15-MeV neutrons under conditions of oxygenation and of anoxia have been fitted to a dose-response curve using the function Y = alpha D + beta D2. An oxygen-enhancement ration (OER) ranging from 3.7 at low yields to 1.6 at high yields was calculated from the coefficients of the dicentric yield curves and evidence is presented which suggests that oxygen does not act as a dose-modifying agent in this system. High dose RBE values of 1.2 and 2.1 with respect to 250 kVp X-rays for oxygenated and anoxic conditions were also obtained. Coefficients for total aberration yield gave similar values to dicentrics for both OER and RBE.