A heat-generating bioactive glass-ceramic for hyperthermia.

Glass plates of the chemical composition: CaO (29.0), SiO 2 (31.0), Fe 2O 3 (40.0), B 2O 3 (3.0), P 2O 5 (3.0) in weight ratio were heated to 1050 degrees C at a rate of 5 degrees C/min and then cooled to laboratory temperature. The resulting glass-ceramic containing magnetite and wollastonite crystals showed high-saturation magnetization. The bonding ability of this new glass-ceramic to bone tissue was evaluated using rabbit tibiae, and compared with glass of the same composition. This glass-ceramic formed a Ca, P-rich layer on its surface and bonded tightly with bone within 8 weeks of implantation. However, the glass did not form this Ca, P-rich layer, nor had it bonded with bone at 25 weeks. The bone-heating ability of this glass-ceramic was investigated by applying a max. 300-Oe, 100-kHz magnetic field. The granules of the glass-ceramic filled in the rabbit tibiae heated the whole surrounding bone to more than 42 degrees C and maintained this temperature for 30 min. Bioactive ceramics reinforce the mechanical strength of bone tissue. Furthermore, this heat-generating bioactive glass-ceramic can be used for hyperthermic treatment of bone tumors.