Local hyperthermia based on soft heating method utilizing temperature-sensitive ferrite rod

A description is given of soft heating, an induction heating method which uses an implantable heater consisting of temperature-sensitive magnetic materials and a metal ring. Local hyperthermia based on soft heating is experimentally shown to be effective. A phantom test reveals that a piece of heater supplies sufficient heat to surrounding tissues whose volume is 1 cm/sup 3/. Wister rats and Walker Carcinosarcoma 256 were used in an animal experiment. Tumors in five rats vanished almost completely after four heating treatments. The accuracy of the regulation is +or-0.2 degrees C near the Curie temperature, which can be readily varied.>