Directly extracting the optical transport coefficients of a turbid medium via time-resolved diffuse reflectance: a Monte Carlo study

摘要

An empirical approach to estimate the reduced scattering (μs’) and absorption (μa) coefficients of a turbid medium fromtime-resolved diffuse reflectance detected at multiple source-detector separations (SDS) is described. The dependence ofthe temporal point spread function (TPSF) on the medium’s optical properties has been previously well studied. Here, weexploit these findings by using the difference in photon arrival-times obtained from a pair of SDS at the (a) peak intensityand (b) longer-time trailing edge of the TPSF to estimate the transport coefficients. This difference may have littledependence on the instrument response functions (IRF). Consequently, real-time quantitation is possible since the methoddoes not depend on non-linear fitting of measured reflectance and/or deconvolving the IRF. The approach uses MonteCarlo simulations to directly translate the difference in arrival times of the temporal reflectance profiles at multiple SDSinto the medium’s optical properties. Here, we show that a small range in the optical properties could be defined using apair of time differences in the TPSF.