Simulation of fan-beam-type optical computed-tomography imaging of strongly scattering and weakly absorbing media

Numerical simulations of the transmission of a light impulse through strongly scattering and weakly absorbing slab media and of fan-beam-type optical computed-tomography imaging for cylindrical media are presented. A hybrid calculation scheme of scattering by the Monte Carlo method is employed to obtain the temporal variation of transmittance of the light impulse through the media. A set of projection data is provided by temporally extrapolating the difference in the optical density between the absorbing object and the nonabsorbing reference to the shortest time of flight. For the case of identical scattering between the object and reference, the reconstructed image of the difference in the absorption coefficient has better accuracy and spatial resolution than those images by the time-gating method.