Microwave Ablation Trocar Operated At Dual Tine Dual-frequency: A Numerical Analysis

Microwave ablation (MWA) is a minimally invasive thermal ablation technique that has the advantages of obtaining high intratumoral temperatures, less treatment time and large ablation region as compared to other thermal ablation techniques. The ablation region obtained during MWA procedure mainly depends on the design and type of the trocar being used. The trocar plays an essential role in the MWA system by governing the energy distribution during tissue ablation. In this study, a novel MWA trocar design has been considered to achieve concentrated ablation region along the tumor's spatial distribution. A dual tine trocar with each tine supplied with energy at different frequencies (2.45 GHz and 6 GHz) has been considered for tumor ablation. Commercially available Finite Element based software has been used (COMSOL-Multiphysics) to analyze the extent of ablation zone. Coupled bioheat and electromagnetic physics interfaces have been utilized. Results showed that the proposed trocar with tines operating at 6 GHz on both the tines leads to a large ablation region (3 cm in diameter) with spherical in shape. Irregularly shaped ablation region can also be achieved by this trocar with tines operating at different frequencies. The minimum time required for complete tumor ablation by the trocar operated at 6 GHz is 4 minutes, followed by 6 minutes for the trocar operated at 2.45 GHz. The proposed trocar can become a part of a better treatment planning system (TPS) based on tumor shape, nearby blood vessel presence, and the trocar's precise insertion.