Alternating Projections of Auxiliary Vector Fields for Electric Field Optimization in Temperature-guided Hyperthermia

We present an alternating projections algorithm (APA) for optimizing the excitations of an antenna array in hyperthermia treatment. The algorithm is based on auxiliary (artificial) complex-vectorial fields that can be derived from temperature or SAR (specific absorption rate) values. These values can be estimated in real-time with the help noninvasive thermometry, like Magnetic Resonance (MR) temperature estimation. The algorithm is tested on data from full-wave simulations of an Agar-gel phantom that is irradiated by a six-element annular array of dipoles. It is shown that, depending on the size and location of the region to be heated, the APA algorithm can outperform the usual eigenvalue optimization with respect to hotspot suppression.