Monte Carlo simulation of low-coherent light transport in highly scattering media: application to OCT diagnostics of blood and skin

摘要

In this paper, we numerically simulated the signals of an optical coherence tomography (OCT) setup from skin and diluted blood (Hct = 5%) layers in order to reveal the possibilities of OCT application to different biological objects at different wavelengths (820 nm for blood and 633 nm for skin), in particular, in relation to the problems of optical clearing of tissues and increasing of penetration depth of the OCT systems. The chosen model parameters coincide with the parameters of a real OCT setup. The optical parameters of simulated biological media coincide with those published in literature. For a blood layer it was shown that the rare borders of a glass cuvette with diluted blood for in vitro investigations can be clearly detected for layer thicknesses up to 1 photon transport pathlength (around 2.3 mm). To calculate the OCT signals from skin two models were used. The simplest model considers skin as a two-layered medium with optical properties of epidermis and dermis. The other model considers skin as a five-layered structure (epidermis, dermis, dermis with plexus superficialis, dermis, dermis with plexus superficialis). Different values of model optical parameters of the layers were used to take into consideration possible deviations of these parameters in biotissues. Dependences of the signal fringe pattern amplitudes from interlayer borders on optical properties of the media were analysed.