Real-time method for fitting time-resolved reflectance and transmittance measurements with a Monte Carlo model

An efficient method is proposed for the evaluation of the absorption and the transport scattering coefficients from a time-resolved reflectance or transmittance distribution. The procedure is based on a library of Monte Carlo simulations and is fast enough to be used in a nonlinear fitting algorithm. Tests performed against both Monte Carlo simulations and experimental measurements on tissue phantoms show that the results are significantly better than those obtained by fitting the data with the diffusion approximation, especially for low values of the scattering coefficient. The method requires an a priori assumption on the value of the anisotropy factor g. Nonetheless, the transport scattering coefficient is rather independent of the exact knowledge of the g value within the range 0.7 < g < 0.9.