Hybrid Simplified Spherical Harmonics with Diffusion Equation for X-Ray Luminescence Computed Tomography

摘要

X-ray luminescence computed tomography (XLCT) combines the high sensitivity of optical imaging with the high spatial resolution of X-ray imaging, and has a more extensive application prospect. An efficient and accurate optical transmission model is very important for XLCT. In optical molecular imaging, the light transmission models we often use are diffusion equation (DE) and simplified spherical harmonic (SP_N). DE has high efficiency but relatively low accuracy, while SP_N has high accuracy but low efficiency. Therefore, the hybrid simplified spherical harmonics with diffusion equation (HSDE) model is proposed. By coupling the DE and SP_N with boundary conditions, the HSDE obtained has both high accuracy and high efficiency. First, each tissue is simulated to determine the best model for it. Then the accuracy and the efficiency of HSDE are verified by forward simulation and inverse simulation for the whole digital mouse model. The results show that the accuracy of HSDE is better than SP_N and the efficiency is higher than DE.