A Novel Multiphysics Optimization-Driven Methodology for the Design of Microwave Ablation Antennas

Microwave ablation is based on localized heating of biological tissues, enabled by an electromagnetic field. Ablation antennas are commonly designed in a forward approach, where the shape and type of antenna are manipulated to generate elevated temperatures in the target region. However, little attention has been dedicated to designing antennas in an inverse approach to allow controlled synthesis of temperature profiles customized for the application, in a reconfigurable way. Also, existing designs are based on generating a particular electric field or SAR profiles, not accounting for discontinuities in the thermal conductivity of tissue. We propose an inverse multiphysics strategy for source design that involves optimizing the current distribution on the antenna to synthesize a desired temperature profile, while accounting for temperature diffusion. We apply this optimization procedure to a simulated test case in human liver and study the associated fields and temperature profiles, as well as the optimized current distributions required. Our results indicate and quantify the clear advantage of this multiphysics approach compared to electric field focusing in terms of meeting objectives in the thermal domain. We show how the optimized current distributions can be easily implemented in a practical design and integrated into treatment planning in a clinical setting.