[Cell loss after combined thermo-radiotherapy. Determination in vivo of the cell-loss rate of euoxic and hypoxic cells of experimental tumors (author's transl)].

Solid Ehrlich cancers with a volume of one millilitre, situated on the necks of mice, were treated with X-rays (150 kV), a low dose of hyperthermia (high frequency), a high dose of hyperthermia and a combined therapy of mild hyperthermia and X-ray irradiation. As labeling method, the technique of 125-I-deoxyuridine was employed. At the time of the therapy, there uas either a majority of hypoxic tumor cells or a majority of euoxic tumor cells, both in labeled form. The loss of cells was measured externally as a decrease of activity between the 96th and the 192th hour after the injection of 125-I. Xray irradiation tends above all to destroy euoxic cells while hypoxic cells are preponderantly destroyed by high doses of hyperthermia. Mild hyperthermia does not influence the cell loss in a significant manner. Mild hyperthermia in combination with X-ray irradiation, however, increases the loss of hypoxic cells up to the rate of euoxic cells.