A challenge to diffuse optical tomography using the radiative transport equation

Diffuse optical tomography (DOT) reconstructs the spatial distribution of optical properties such as an absorption coefficient and a scattering coefficient of the tissues using near-infrared light. Light propagation in a scattering medium is governed by the radiative transfer equation (RTE). However, most studies rely on the diffusion approximation of the RTE because it is difficult and challenging to solve numerically. We have developed the effective numerical calculation algorithms for the RTE forward problem and compared these results with those by the actual phantom experiments, which revealed the limits of the diffusion approximation and the validity of the RTE for describing light propagation in a scattering medium.