Simulation of the OCT-depth signal of homogeneous turbid media using a modified Monte-Carlo model

Optical coherence tomography (OCT) is widely used for imaging of biological tissue. The extraction of quantitative information such as the scattering coefficient μ_s is straight forward only for weakly scattering media where ballistic photon scattering can be assumed. For strongly scattering media multiple scattering has to be considered. Photons, which are scattered more than once, but are still within the coherence length of the OCT, also contribute to the signal and change the slope. Also, a cluster of equal scatterers can appear as one single scatterer with different optical properties. These effects lead to concentration dependent scattering. We present a simple model to simulate OCT depth signals in weakly and strongly scattering media. In our extended MCML implementation photons are collected in bins representing the number of undergone scattering events. A weighting function rescales the photon signal according to its bin. Based on a parameter study of this weighting function we are able to implicitly predict the influence of dependent scattering without modeling the process explicitly. In future, our quantitative approach could improve biological imaging.