Microwave hyperthermia as an adjuvant to radiotherapy and chemotherapy has shown
promising results in the overall survival of cancer patients. In our previous work, we developed
a microwave phased array (PA) applicator for hyperthermia treatment (HT) of locally advanced
breast cancer (LABC) with very good healthy tissue hotspot control and targeted heating of the
tumor. In this work, we report the design optimization of our existing applicator for developing
a compact clinical device for HT delivery. Several PA applicator designs of varying shapes and
antenna configurations were investigated using cavity-backed 434 MHz patch antennas. Three
dimensional (3D) layered homogeneous breast models of varying volumes and tumor locations,
and time reversal algorithm were used to assess the ability of PA designs to steer and selectively
deposit power at the tumor. The best performing PA design was assesed on patient derived 3D
heterogeneous breast models using multi-objective genetic algorithm for determining
excitation magnitude and phase for the PA. The performance of the optimized PA applicator
was compared with our existing PA applicator in patient derived heterogeneous and layered
homogeneous 3D breast models. A seven fold increase in mean specific absorption rate in
tumor was osberved for the optimized PA applicator with healthy tissue hotspot to target ratio
comparable to the existing applicator. Up to three fold decrease in the maximum power
requirement was also observed for the optimized applicator when compared to our existing
applicator. The proposed PA applicator is integrated in a treatment table to realize a clinical
device for HT of LABC.
KEYWORDS: Breast cancer, Hyperthermia treatment, Microwave, Multi-objective Genetic
Algorithm, Phased array applicator