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Proceedings Paper

Time-resolved reflectance measurements on layered tissues with strongly varying optical properties
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Paper Abstract

Most biological tissues consist of layers with different optical properties. A few examples are the skin, the esophagus, the stomach and the wall of arteries. An understanding of how the light propagates in such layered systems is a prerequisite for any light based therapy or diagnostic scheme. In this study we investigate the influence of different kinds of layers on time resolved reflectance measurements. Experiments were performed on layered gel phantoms and the results compared to Monte Carlo simulations and diffusion theory. It is shown that when a low absorbing medium is situated on top of a high absorbing medium, the absorption coefficient of the lower layer is accessible if the differences in the absorption coefficient are only small. In the case of large difference the optical properties of the upper layer dominate the signal and shield information on the lowest layer. The degree of this shielding effect depends on layer thickness as well as optical properties. In the case of an almost absorption and scattering free layer in between two normal tissues, an overall increase of the signal is visible. However, the overall shape of the curve is about preserved. The apparent scattering coefficient is slightly decreased, while the apparent absorption coefficient is unaltered.

Paper Details

Date Published: 18 January 1995
PDF: 9 pages
Proc. SPIE 2323, Laser Interaction with Hard and Soft Tissue II, (18 January 1995); doi: 10.1117/12.199216
Show Author Affiliations
Andreas H. Hielscher, Rice Univ. and Univ. of Texas M.D. Ancerson Cancer Ctr. (United States)
Hanli Liu, Univ. of Pennsylvania (United States)
Lihong V. Wang, Univ. of Texas M.D. Anderson Cancer Ctr. (United States)
Frank K. Tittel, Rice Univ. (United States)
Britton Chance, Univ. of Pennsylvania (United States)
Steven L. Jacques, Univ. of Texas M.D. Anderson Cancer Ctr. (United States)

Published in SPIE Proceedings Vol. 2323:
Laser Interaction with Hard and Soft Tissue II
Hans Joerg Albrecht; Guy P. Delacretaz; Thomas H. Meier; Rudolf W. Steiner; Lars Othar Svaasand; Martin J. C. van Gemert, Editor(s)

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