Computer simulation studies of spatially resolved speckle correlometry in application to tissue structure characterization

Abstract

Monte Carlo modeling of light transport in tissues with complex structure and dynamics using an original approach of speckle-correlometry based on ring-like apertures and localized source of probe light are presented. The dynamic long inclusions with different geometry and depth location in the static inhomogeneous layer imitated biotissue with different characteristics of microcirculation were chosen as a simulated medium. In the simulations, the refractive-index of static tissue – dynamic inclusion boundary is not match, thus the phenomenon of internal multiple reflection takes place. The backscattering coefficient of laser light scattered by the simulated medium evaluated as a ratio of the dynamic partial components of the backscattered field to the full backscattered field is obtained. At the same time the dynamic partial components of the backscattered field and the full backscattered field are detected by the ring detector with the set value of ring aperture radius. Also it was shown that the dependences of the backscattering coefficient on the ring detector radius calculated for all simulated medium has an asymptotic value. The ratio of the asymptotic values of backscattering coefficient is determined by the ratio of the dynamic inclusion diameters. The displacing of the dynamic object along the surface relative to the point of laser light incidence lead to reducing of the asymptotic value of the backscattering coefficient.