Fast photon-boundary intersection computation for Monte Carlo simulation of photon migration

Abstract

Monte Carlo (MC) method is generally used as a "gold standard" technique to simulate photon transport in biomedical optics. However, it is quite time-consuming since abundant photon propagations need to be simulated in order to achieve an accurate result. In the case of complicated geometry, the computation speed is bound up with the calculation of the intersection between the photon transmission path and media boundary. The ray-triangle-based method is often used to calculate the photon-boundary intersection in the shape-based MC simulation for light propagation, but it is still relatively time-consuming. We present a fast way to determine the photon-boundary intersection. Triangle meshes are used to describe the boundary structure. A line segment instead of a ray is used to check if there exists a photon-boundary intersection, as the next location of the photon in light transports is determined by the step size. Results suggest that by simply replacing the conventional ray-triangle-based method with the proposed line segment-triangle-based method, the MC simulation for light propagation in the mouse model can be speeded up by more than 35%.