Finite Element Simulation of Pulsed Laser-induced Thermotherapy for Biological Liver Tissue

摘要

Laser-induced thermotherapy (LITT) predicts the effects of laser applications in LITT and optimizes the efficacy of irradiation plans, the light distribution in liver tissue, the optical tissue properties, and the changes caused by thermal denaturation. In this paper, COMSOL Multiphysics, a commercially available Finite Element (FE) simulation software package, was used to simulate the interaction between laser and liver tissue. A short-pulse laser point source, coagulated liver tissue and uniform soft tissue submerged in water were established. In this study, two sets of simulation models were used to describe the principles: 1) Diffusion equation was used to simulate light propagation; 2) Temperature changes were simulated using biothermal equations. The experimental results show that there are significant differences in penetration depth and light energy distribution of native and coagulated liver tissues under laser irradiation with different wavelengths. The penetration depth of the liver tissue after heat coagulation is significantly reduced. In addition, the simulation can present the temperature curve during the clinical hyperthermia of liver cancer and determine the effect by various treatment parameters. These results provide a better understanding of laser-tissue interactions and may be helpful to researchers in the fields of laser medical.