An inverse Monte-Carlo method for determining tissue optical properties

In this paper, a Monte Carlo based model of diffuse reflectance is introduced to retrieve the light absorption and scattering coefficients of multi-layered tissue. The model consists of a forward part and an inverse one. The forward refers to a multi-layered Monte Carlo simulation at a certain source-detector separation, which lead to a time-resolved profile. The inverse one is a fitting procedure based on Levenberg-Marquardt algorithm using forward model in iteration, and the intensity in time bins is fitted. The model was tested with independent Monte Carlo simulations and fiber-optic-based measurement in the deduced absorption and reduced scattering coefficients. Although a high amount of computation time is needed, this model is developed as a verification standard to these investigation methods using diffuse approximation to the transport equation. Furthermore, it is adaptable to the complex fiber-optic probe geometries.