Cancer detection studies using a 4.7 Gigahertz radiometer.

Our laboratory has begun to evaluate the cancer detection capabilities of a microwave thermographic unit that employs a 4.7 GHz radiometer. The technique is passive and noninvasive. The temperature sensitivity of the unit is less than 0.1 degrees C. Malignant tumors are often about 1 degree C warmer than normal tissues. Microwave radiometry can provide information related to subsurface temperatures, whereas infrared thermography is limited to surface temperatures. Positive results were obtained in four of six biopsy-proved primary carcinomas of the breast, in four of four patients with lymphoma, and in nine of ten women with recurrent breast cancer. Negative results were obtained in patients with deeply seated tumors such as in lung, liver, esophagus, femur, and humerus. Microwave thermography is a promising new method of noninvasive cancer detection, and the choice of a 4.7 GHz frequency may represent an improvement over units operated at other frequencies.