Vector Finite Element Method For Microwave Ablation

Abstract

ABSTRACT KEYWORDS: Microwave ablation; Liver cancer; Maxwell equation; Bioheat equation; newlineCell death model Microwave ablation (MWA) is a thermal cancer treatment method that utilizes electromagnetic waves to generate heat within the tissue. The primary objective of this treatment is to kill the tumor cells by inducing heat in the tissue while minimizing damage to healthy cells. During MWA, one or more antennas are directly inserted into the target tissue. MWA employs electromagnetic waves oscillating at around 1 GHz and higher,which are coupled to the tissue through an antenna. Heat is produced as polar molecules and ions in the tissue continuously realign with the alternating field. Conducting experiments on biological tissue is necessary to study input parameter analysis,antenna placement, and the effect of heat distribution on the ablation zone before treatment. However, experiments are both time-consuming and expensive. Therefore, our focus was on mathematical modeling and computational techniques for MWA to predict heat distribution before treatment without the need for experiments on living organisms. MWA is primarily defined by three physical phenomena: microwave absorption by tissue, heat distribution in the tissue, and thermal damage to the tissue. These phenomena are analyzed through wave propagation, bioheat, and cell death models, respectively. We have used solution space H(curl, and#937;) instead of (H1(and#937;))d (d=2,3) for the wave propagation model to enhance accuracy and reduce computation time in numerical simulations.To analyze microwave absorption by tissue,we developed both two-dimensional axisymmetric and three-dimensional vector finite element methods for the wave propagation model. Subsequently,we compared the accuracy and computation time of the vector finite element method with existing methods in the literature.Additionally,we investigated the effects of constant and pulsating power on the ablation zone. We enhanced the efficiency of microwave ablation by sequentially introducing antennas in a cell.