Effect of hypothermia and irradiation on transplantable animal tumors

Compared is a radiosensitizing effect of heating on two rat neoplasms, which are different in radiosensitivity and growth kinetics rate. The first is fibrosarcoma, the second - slowly growing rabdomyosarcoma. Radiosensitizing effect of hyperthermia was revealed to a more considerable extent in relation to slowly growing radioresistant neoplasm. Investigated were regularities of mitotic activity variation in rabdomyosarcoma, subjected to single exposure at 2000 rad dose rate, heating and combined effect of irradiation and heating. Separate applying of used factors has resulted in slight mitotic activity inhibition. Under combined effect of ionizing radiation and hyperthermia considerable oppression of mitotic tumour cell activity was being observed for the first four days. The experiments results testify to perspectives of application of hyperthermia effect to overcome significant radioresistance of slowly proliferating tumour cells