An inexpensive variable‐frequency microwave system for hyperthermia

A microwave hyperthermia system is described which uses surplus communications equipment. The most costly components of the microwave system, the signal generator and amplifier, were obtained through the Federal Surplus Supply System. The cost of the entire system, including the 2450 MHz applicator and temperature monitoring system, is under $1200. Extensive testing has demonstrated the capability of heating several cm3 mouse tumors to a temperature of 42.5 °C. Depth of heating can be varied by adjusting the frequency of the oscillator or by adjusting the output attenuator.