In this work, tritiated water (HTO) added to the medium was used to induce the oncological transformation of mouse C3H10T1/2 cells. At HTO concentrations of 37 and 3.7 MBq/ml the doses to the asynchronous, actively proliferating cultures were delivered at rates of about 10 and 1 cGy/h. Each dose rate was maintained at a constant level throughout the experiments and total doses of 35, 70, 105 and 140 cGy were varied by changing the duration of incubation with tritiated water.
The resulting transformation frequencies were similar when the same total dose was given at 10 and 1 cGy/h. Their values rose linearly with the dose without any evidence of a theresold or quadratic component.