A PRECLINICAL SYSTEM FOR ENHANCING THE EFFICIENCY OF MICROWAVE BREAST CANCER HYPERTHERMIA THERAPY USING DIELECTRIC MATCHED LAYER AND CONVEX LENSES

Convex lenses can be used in adjuvant with microwave sources to produce appropriate focus spots for breast cancer hyperthermia therapy. A preclinical system was assessed using a horn antenna together with a convex lens. The horn antenna was built to accommodate the lens size so as to minimize wave spillover. Here, a modified hyperthermia system was tested on a hemisphere phantom of scattered fibro glandular breast tissue with cancer stages I & II. The focus spots were at different locations and depths (up to 2.7 cm) under the skin layer. Transmission and reflection coefficients at the air-breast phantom interface were calculated to determine the best operating frequency (2.45 GHz) for efficient power absorption. Based on these computations, an external dielectric matched layer was added onto the skin of the breast phantom to decrease reflection that would occur between water and skin. This arrangement increased wave transmission inside the breast without increasing applicator input feed. The system could heat regions of tumor at various locations independently using only one applicator. The whole system was fabricated, and measurements were taken to validate the simulated and analytical results.