Studies on Cell-survival of Irradiated Ehrlich Ascites Tumour

Abstract
(1) Survival-curves were obtained for a tetraploid Ehrlich ascites tumour after irradiation with 200 kv x-rays and with fast neutrons in the presence or absence of oxygen. (2) The oxygen-enhancement ratio for 200 kv x-rays was found to be 3·1 and for fast neutrons 1·8. (3) The RBE of fast neutrons relative to 200 kv x-rays was found to be 2·1 in oxygen and 3·6 in nitrogen. (4) These results have been discussed with reference to similar results obtained on telophase abnormality studies in the same tumour.