Muscle heating produced in hog specimens by microwaves at 915 and 433.92 Megahertz

It has been demonstrated in a plane layered specimen with thin and thick fat layers that the heating patterns produced by a 915 MHz contact applicator and the round field applicator operating at a frequency of 433.92 MHz are similar. Theoretically, an applicator operating at the frequency of 433.92 MHz showed deeper penetration than those operating at higher frequencies, however, the fact that the 915 MHz applicator was applied with superficial cooling tends to minimize the difference between the resultant temperature distribution. Also the frequency of 915 MHz is an approved diathermy frequency in the United States whereas the frequency of 433.92 MHz is not. The results obtained in this comparative study of the 915 MHz contact applicator concur with the previously published results that were obtained in evaluating this applicator in specimens. Further studies of the 433.92 MHz will now be undertaken in human subjects to determine what effects physiological changes produced by the heating will have on the heating patterns.