INFLUENCE OF GAMMA-IRRADIATION ON THE DEVELOPMENT OF NEOPLASTIC DISEASE IN MICE .2. SOLID TUMORS

The influence of 137Cs γ irradiation on the development of solid tumors was investigated using male and female RFM/Un mice. In females the tumor types for which data were sufficient to allow analysis of the form of the dose-response relationship were ovarian, pituitary, and Harderian gland tumors. In males analysis of the dose response was only possible for Harderian gland tumors. The data suggest that a threshold estimated to be 11 to 12 rad may exist for the induction of ovarian tumors. Above this threshold the incidence increased with the square of the dose. A linear-dose-squared model described the dose-response relationship for pituitary tumors in females and Harderian gland tumors in both males and females. The incidences of other tumors were individually too low to allow analysis. The need for understanding the biological basis for the form of the dose response is discussed.