科研之友
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摘要
Expanding our previously proposed "time segment analysis" for a two-layered turbid medium, this study attempted to selectively determine the absorption coefficient (mu(a)) of the bottom layer in a four-layered human head model with time-domain near-infrared measurements. The difference curve in the temporal profiles of the light attenuation between an object and a reference medium, which are obtained from Monte Carlo simulations, is divided into segments along the time axis, and a slope for each segment is calculated to obtain the depth-dependent mu(a) (mu(seg)(a)). The reduced scattering coefficient (mu'(s)) of the reference is determined by curve fitting with the temporal point spread function derived from the analytical solution of the diffusion equation to the time-resolved reflectance of the object. The deviation of mu(seg)(a) from the actual mu(a) is expressed by a function of the ratio of mu(seg)(a) in an earlier time segment to that in a later segment for mediums with different optical properties and thicknesses of the upper layers. Using this function, it is possible to determine the mu(a) of the bottom layer in a four-layered epoxy resin-based phantom. These results suggest that the method reported here has potential for determining the mu(a) of the cerebral tissue in humans. (C) The Authors. Published by SPIE under a Creative Commons Attribution 3.0 Unported License. Distribution or reproduction of this work in whole or in part requires full attribution of the original publication, including its DOI.
- 出版日期2013-9
- 单位河北医科大学
