New magnetic implant material for interstitial hyperthermia

Magnetic properties and heat generation characteristics of a bio-compatible ceramic Mg1+xFe2–2xTixO4 system have been investigated as an implant material for the magnetic induction hyperthermia. Curie temperature (Tc) of the ceramic decreases with increasing x; and become Tc, 350 K at x ç0:35 and, 315 K at x ç 0:38; which is suitable Curie temperature for implant material. The temperature of ceramic as a function of time under the high frequency alternating magnetic field is self-controlled at Tc.The surface temperature of a powder injection sphere cancer model, which was a mixture of the agar phantom and the ceramic powder implant, and the temperature distribution around the sphere set in the pure agar phantom matrix have been measured. The result is in good agreement with calculation using a finite element method (FEM). It was found that the temperature distribution inside of the sphere and the minimum quantity of Mg1+xFe2–2xTixO4 necessary for hyperthermia could be estimated by the FEM calculation.