Total body hyperthermia induced by a computerized microwave technique: studies in normal rats and in rats with liver tumors.

A computerized system for inducing total body hyperthermia by microwave irradiation was tested in rats. The tolerance to hyperthermia at different temperatures and fractions was studied as well as its effect on the growth of transplanted adenocarcinomas in the liver. Survival results indicated that 41.5 degrees C was maximum tolerated temperature both after single and repeated one hour exposures. Besides the high mortality with a greater temperature (42 degrees C) there was a significant rise in S-aspartate-amino-transferase (S-ASAT) and S-beta-hexosaminidase (beta-nagas) indicating damage of normal cells. No significant reduction of tumor volume could be registered after treatment with total body hyperthermia (41.5 degrees C) for one hour three times during a 24 hour period.