FERROMAGNETIC HYPERTHERMIA IN RABBIT EYES USING A NEW GLASS-CERAMIC THERMOSEED

Hyperthermia is a new treatment modality to increase the tumoricidal e ffect of radiotherapy for choroidal melanoma. We have produced a ferro magnetic glass-ceramic composed of magnetite and wollastonite as a the rmoseed for interstitial hyperthermia. The stable oxidized ceramic pro duced sufficient heat by hysteresis loss upon exposure to an alternati ng magnetic field. We studied its heat-generating properties and evalu ated its possible application to ocular hyperthermia. Agar model and r abbit eye studies showed that the heat generated by the ceramic was le ss affected by its orientation in the magnetic field than metal alloy thermoseeds and that the retinal surface was heated to 43.5-degrees-C in less than 7 min without heating the surrounding tissue. Additionall y, this heating system showed a good temperature stability of +/-0.1-d egrees-C under steady-state conditions without using a controller. The new glass-ceramic shows promise as a thermoseed in ocular hyperthermi a.