MILD TEMPERATURE HYPERTHERMIA COMBINED WITH CARBOGEN BREATHING INCREASES TUMOR PARTIAL-PRESSURE OF OXYGEN (PO(2)) AND RADIOSENSITIVITY

The partial pressure of oxygen (pO(2)) of FSaII tumors grown in the le g of C3H mice significantly improved when the tumors were heated hy im mersing the tumor-bearing legs in a water bath at 41.5 degrees C for 6 0 min. The tumor pO(2) also substantially increased when the tumor-bea ring mice breathed carbogen (95% O-2:5% CO2). Additionally, mild hyper thermia followed by carbogen breathing further increased the tumor pO( 2) and increased radiation cytotoxicity as assessed by the in vivolin vitro excision assay for surviving FSaII cells. It was concluded that mild hyperthermia in combination with carbogen breathing is potentiall y useful to reoxygenate radioresistant hypoxic cells and improve the r adiotherapy of human tumors.