Penetration depth of diffused photons re-emitted from layered tissue and its application to near infrared spectroscopy

摘要

Concept of penetration depth of diffused photons migrating in turbid medium is introduced, and subsequently, distribution of penetration depth and mean penetration depth in three-layered media are investigated by using of Monte Carlo simulation technique. An optimal source-detector separation is derived from the mean penetration depth referring to monitoring the change of chromophore concentration of the sandwiched layer. In order to verify the separation, we perform Monte Carlo simulations 80 times with varied absorption coefficient of the sandwiched layer. All these diffuse reflectance of 80 times of Monte Carlo simulations are used to construct a calibration model with the method of PLS. High correlation coefficients and low RMSEP at the optimal separation have conformed correctness of the selection.