Hyperthermia of mouse lungs: technique and control of critical parameters.

A microwave heating technique which combines essential life support, monitoring and heating systems has been developed, and is in use for the investigation of pathophysiological responses of the murine lung to hyperthermia alone and in combination with other therapeutic modalities. The technique enables heating of most of the lung volume to within 1 to 1.5 degrees C of the target temperature. To ensure reproducibility and develop a programmed heating regimen, we have controlled microwave power, coupling of microwave power into the animal and surface temperature as well as respiration frequency, volume and temperature of inspired air and central core temperature. Cardiac function is also monitored via EKG and heart rate. With these controls, and a thermal probe in contact with the lung, we can achieve a given target temperature at a specified microwave power level and maintain that temperature within +/- 0.5 degree C for the desired heating time without surface burns and little or no procedure-related acute lethality.