Photon Migration Model for Turbid Biological Medium Having Various Shapes

Abstract
Fundamental, yet novel, formulas representing diffuse re-emission of short-light-pulse incidence on turbid media independent of their shapes are deduced from a simple photon migration model in which the survival probability of a photon is determined by the zigzag photon path length and the absorption coefficient within the medium. The results can be applied to derive the absolute concentration of the absorptive constituent in variously shaped media. The coincidence between our model and the diffusion equation is seen if we adopt a new diffusion coefficient independent of the absorption coefficient.