Abstract
Anti-tumor effects of radiofrequency hyperthermia on experimental malignant glioma of rats were examined. Radiofrequency electromagnetic fields at 13.56 MHz were used to heat locally subcutaneously-transplanted Rous sarcoma virus-induced rat gliomas. Temperature profiles during radiofrequency treatment showed that the temperature in the tumor was constantly higher by 2 ?? 5°C than that in the surrounding subcutaneous tissue. The tumor temperature was maintained at a stable level throughout the treatment by adjusting the radiofrequency power.
Following results were obtained: 1) The critical temperature to bring about anti-tumor effects such as delay of tumor growth or extension of the survival of the animals was 43°C. 2) Longer or repeated heating enhanced the anti-tumor effects. 3) Combined therapy consisting of radiofrequency hyperthermia and 60Co-irradiation or an anticancer drug, ACNU, showed greater anti-tumor effects than hyperthermia only.
