Analytical prediction and numerical confirmation of deep focused microwave hyperthermia in a human head

By carefully selecting the electric field distribution around the entire surface of a human head, it is possible to generate a tightly-focused global power maximum at the deepest point within the brain. An analytic prediction of the optimum volume field distribution in a layered concentric head model is derived based on spherical harmonics, and a three-dimensional finite difference time domain (FDTD) computation using the corresponding source field for a discretized, MRI-based head model gives a very similar dissipated power distribution. This study demonstrates that microwave hyperthermia can be a feasible cancer treatment modality for tumors in the head, providing a well-resolved “hotspot” at depth without overheating any other healthy tissue