Numerical simulation of microwave ablation of lung tumor near the bronchus

This paper aims to investigate the key factors affecting the efficacy of microwave ablation (MWA) of lung tumors near the bronchus. A lung anatomical model with three-level bronchial branches was established and a finite element analysis was developed to determine the temperature distribution. The ablation effect under different antenna-bronchial outer wall spacing, air velocity, and tumor diameter was compared and evaluated. The results show that there is a heat sink effect significantly related to the distance of antenna-bronchial outer wall. When the distance increases from 5.0 mm to 12.5 mm, the ablation volume of lung tissue increases by 0.96 cm³, while the air velocity increases from 0.5 m/s to 1.0 m/s, the maximum ablation volume decreases by 0.11 cm³. Tumor size also has a significant effect on MWA. When a 1 cm-diameter tumor is close to the bronchial outer wall, even if we choose the ablation scheme with less energy, which is [40 W, 2 min], the ablation process still penetrates the bronchus. The increase in tumor size leads to the increase of incomplete ablation rate. For 2 cm-diameter tumor, it is necessary to choose the ablation combination with higher energy [50 W, 8 min] or [60 W, 5 min] to avoid inadequate ablation.