[Influence of the dose rate on the therapeutic effect of 60Co-gamma-irradiation in murine adenocarcinoma (author's transl)].

Transplantable adenocarcinomas of C3H-mice were irradiated with doses between 7 and 75 Gy, using a dose rate of 3.6 Gy/min, or with doses from 10 to 80 Gy using dose rates between 0.06 and 0.17 Gy/min from a 60Co-gamma source. A radiation-induced delay of growth or the local cure were recorded. The relative effectiveness of irradiation of the tumor using a low dose rate decreases at first down to a value of 0.66 at 25 to 30 Gy, if the doses are increased; then, if the doses delivered are further increased, it mounts again to 0.88 when the median curative radiation dose is reached.