Evaluating antenna configurations for improved microwave therapy outcomes in liver tumors enhanced with magnetic nanoparticles

Abstract

The effects of geometric parameters on microwave thermal therapy, enhanced with magnetic nanoparticles, for liver cancer are investigated. Using finite element analysis and considering various tumor diameters ranging from 20 to 40 mm, the number and placement of antenna slots, antenna positioning, and slot spacing were evaluated to improve treatment efficacy. Numerical results indicate that three-slot antennas provide superior performance by generating uniform electromagnetic field that reduces collateral damage, whereas five-slot configurations increased healthy tissue necrosis by up to 124 % for smaller tumors. Moreover, slot spacing has a negligible effect in nanoparticle-enhanced treatments, as the nanoparticles dominated heat distribution. Positioning the antenna tip at the tumor's edge can reduce treatment times and side effects, limiting healthy tissue damage by 21–79 %, depending on tumor size and offset. For tumors of diameters larger than 35 mm, positioning effects diminish, as necrosis volume stabilized across different placements. Compared to a 25 mm tumor, the 20 mm tumor showed that 67 % of the increase in necrosis volume was due to healthy tissue damage, even though the treated tumor volume was 95 % larger. This efficiency can be improved with tumor size; for a 40 mm tumor, the increase in healthy tissue necrosis was only 27 %, despite the tumor being 49 % larger. The location of gap also played a role, smaller gaps near the antenna tip improve tumor coverage and reduce side effects, but variations in gap location had minimal impact on healthy tissue necrosis. These results demonstrate that appropriate geometric configurations in microwave thermal therapy can enhance tumor ablation while minimizing collateral damage, particularly for larger tumors. © 2025 Elsevier Ltd.