A Diathermy Applicator for the Irradiation of Rat Brain

A direct contact microwave applicator, constructed of dielectric-loaded J-band waveguide, was designed for local irradiation of the rat head with 2450 MHz CW microwaves. A stereotaxic method was used to achieve precise and reproducible orientation of the Applicator with the animal's head. Calorimetric measurements of specific bsorption rate, watts/kg, for the whole head indicated that approximately 62 percent of the net power applied to the applicator is absorbed in the head, and that a reproducible exposure condition could be achieved from one animal to the next. Thermographic pictures were taken of the bisected rat head immediately after exposure, and showed that the maximum rate of energy absorption took place within the brain, in the thalamus and mesencephalon.