Visualization of the photothermal effect of mouse brain based on Monte Carlo and finite element method

Abstract

Photothermal imaging plays an important role in brain structural and functional imaging. However, the skull has a strong scattering effect on photons, it is necessary to study the propagation behavior and thermal effect of photons in brain. In this study, MCmatlab, an open source program in MATLAB, which combines the Monte Carlo method with finite element method, was used to build a photothermal model of mouse brain to simulate the movement of photons in mouse brain. Monte Carlo method is commonly used to solve the distribution of light in biological tissues, and FEM (Finite Element Method) can effectively solve the distribution of optical parameters in biological tissues, and helps to obtain an approximate solution of the radiation transfer equation (RTE). By constructing a 3D model to observe the structure of each layer of the brain more intuitively, the laser pulse propagation in the mouse brain and the temperature distribution of each layer of brain tissue were obtained by the RTE solver and the finite element thermal diffusion solver included in MCmatlab.