Multi-Frequency Constrained SAR Focusing for Patient Specific Hyperthermia Treatment

In hyperthermia treatments, the possibility of generating a specific absorption rate distribution peaked into the tumor and bounded elsewhere represents the main clinical need. As multi-frequency applicators can be exploited to reduce the occurrence of undesired hot-spots, an optimal multi-frequency approach is proposed and discussed. Being formulated in terms of a convex programming problem, the globally optimal solution can be determined (only for very special cases). The procedure, presented for the case of scalar fields, can be extended both to the case of vector fields and to the more interesting problem of shaping (rather than just focusing) the specific absorption rate distribution.