Effect of high blood flow on heat distribution and ablation zone during microwave ablation-numerical approach

Abstract

Microwave ablation has become a viable alternative for cancer treatment for patients who cannot undergo surgery. During this procedure, a single-slot coaxial antenna is employed to effectively deliver microwave energy to the targeted tissue. The success of the treatment was measured by the amount of ablation zone created during the ablation procedure. The significantly large blood vessel placed near the antenna causes heat dissipation by convection around the blood vessel. The heat sink effect could result in insufficient ablation, raising the risk of local tumor recurrence. In this study, we investigated the heat loss due to large blood vessels and the relationship between blood velocity and temperature distribution. The hepatic artery, with a diameter of 4 mm and a height of 50 mm and two branches, is considered in the computational domain. The temperature profile, localized tissue contraction, and ablation zones were simulated for initial blood velocities 0.05, 0.1, and 0.16 m/s using the 3D Pennes bio-heat equation, temperature–time dependent model, and cell death model, respectively. Temperature-dependent blood velocity is modeled using the Navier–Stokes equation, and the fluid–solid interaction boundary is treated as a convective boundary. For discretization, we utilized $H\left(\mathrm{curl},\Omega \right)$ elements for the wave propagation model, $H^1\left(\Omega \right)$ elements for the Pennes bio-heat model, and ${\left(H^1\left(\Omega \right)\right)}^3\times L_0^2\left(\Omega \right)$ elements for the Navier–Stokes equation, where $\Omega$ represents the computational domain. The simulated results show that blood vessels and blood velocity have a significant impact on temperature distribution, tissue contraction, and the volume of the ablation zone.