Development of inductive regional heating system for breast hyperthermia

In response to demand for clinical use, a simple noninvasive regional heati ng applicator system for breast hyperthermia has been developed using ferri te cores. Since the breast is positioned between a pair of ferrite cores, i t is possible to regionally heat it without considering the dimension of th e breast. To find a method of controlling the heating position horizontally and vertically, magnetic-held distributions are analyzed using the three-d imensional finite-element method. Theoretical analyses suggest that a condu ctive thin plate and a novel eddy current absorber are effective for contro lling the maximum heating position. A new applicator system operates at a f requency of 4 MHz and a maximum output power of 600 W, Heating tests using an agar phantom and rabbits show a temperature rise of more than 8 degreesC at a depth of 8 cm after heating for 10 min without heating fatty tissue.