Investigation of light piping through clear regions of scattering objects

摘要

Abstract: Near-infrared spectroscopy is increasingly being used for monitoring cerebral oxygenation and haemodynamics. One current concern is the effect of the cerebrospinal fluid upon the distribution of light in the head. There are difficulties in modeling clear layers in scattering systems. The Monte Carlo model should handle clear regions accurately, but is too slow to be used for realistic geometries. The diffusion equation can be solved quickly for realistic geometries, but is only valid in scattering regions. In this paper we describe experiments carried out on a solid slab phantom to investigate the effect of clear regions. These experiments were used to examine the accuracy with which the different models described propagation through a clear layer inside a scattering object. We found that the presence of a clear layer had a significant effect upon the light distribution, which was modeled correctly by Monto Carlo techniques, but not by diffusion theory. !19