THE EFFECT OF MICROWAVES ON BONE AND BONE MARROW AND ON ADJACENT TISSUES
Joseph P. Engel et al. · 1950
Researchers exposed anesthetized and trained dogs to microwave diathermy at 2,450 megacycles per second and measured temperature changes in tibial cortex, marrow, muscle, and subcutaneous tissue. For subcutaneously located bone, 30 minutes at 65 watts raised tibial cortex temperature by 5.0 degrees (C.) and marrow by 3.4 degrees (C.). For submuscularly located bone, the same exposure raised cortex by 3.8 degrees (C.) and marrow by 3.0 degrees (C.). A rectangular director allowed higher temperatures in subcutaneously located bone without excessively heating adjacent soft tissue. An impedance-matching transformer increased tissue temperature rises by approximately 300 per cent.