Characteristics of Temperature Sensitive Magnetic Powders for Soft Heating and Their Application to Hyperthermia

The basic characteristics of a soft heating method utilizing temperature-sensitive magnetic powders were examined. Soft heating has the following advantages: (1) objects for implantation can be formed in any desired shape, and (2) it should be easy to transfer the powder to deep tissue by magnetic induction. However, no magnetic powder has yet been developed which can produce sufficient heat to reach desired temperatures. In order to generate more heat, metal rings were imbedded in a powder, and eddy current losses within them were utilized. The maximum heat was obtained by using rings of optimum resistance and density.