Applicability expansion of diffusion approximation to high-absorption medium for scattering measurement: - For noninvasive evaluation of blood turbidity using backscattered light -

A technique to estimate the reduced scattering coefficient from spatially resolved backscattered light was developed using the solution of diffusion approximation. However, the diffusion approximation is valid in a scattering-dominant case. An exact solution for the reduced scattering coefficient was newly obtained using the special modification factor, which expands the applicability of the diffusion approximation to the case of absorption media such as the human blood. The validity of the simulation and the applicability of the proposed technique were verified with measurements using tissue and blood-simulating turbid media.