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Proceedings Paper

A method to improve reconstruction of the distribution of hemoglobin, oxygenation, and MLu concentration in the human prostate before and after photodynamic therapy
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Paper Abstract

Explicit dosimetry of photodynamic therapy requires detailed knowledge of the light, drug, and oxygenation distributions within the target tissue. We present a method for the optical detection and three-dimensional reconstruction of hemoglobin concentration and oxygenation and sensitizer concentration within the human prostate. Spectrally resolved diffuse transmission measurements were made using a small isotropic fiber-based white light source and an isotropic detector inserted into the prostate via parallel closed transparent catheters. The spectra were modeled using the diffusion approximation appropriate for infinite media. The optical absorption of the prostate was assumed to be a linear combination of the absorption spectra of oxy- and deoxyhemoglobin and MLu, and the scattering was assumed to be of the form A(&lgr;/&lgr;0)-b. The separation of absorption and scattering coefficients was accomplished based on the spectral shape of the diffuse transmission, rather than the spatial variation in intensity. By making multiple measurements at various source-detector separations, we investigate the signal-to-noise sensitivity of our algorithm. In addition, the redundancy in our source-detector position matrix creates several positions in which the tissue parameters can be reconstructed from multiple independent measurements, allowing an assessment of the repeatability of the algorithm. We find significant heterogeneity in the reconstructed optical properties; however the recovery of spectrally consistent absorption and scattering spectra is improved compared to wavelength-wise reconstruction algorithms.

Paper Details

Date Published: 27 February 2007
PDF: 10 pages
Proc. SPIE 6427, Optical Methods for Tumor Treatment and Detection: Mechanisms and Techniques in Photodynamic Therapy XVI, 64270K (27 February 2007); doi: 10.1117/12.699545
Show Author Affiliations
Jarod C. Finlay, Univ. of Pennsylvania (United States)
Timothy C. Zhu, Univ. of Pennsylvania (United States)
Xiaodong Zhou, Univ. of Pennsylvania (United States)
Andreea Dimofte, Univ. of Pennsylvania (United States)
S. B. Malkowicz, Univ. of Pennsylvania (United States)
Stephen M. Hahn, Univ. of Pennsylvania (United States)

Published in SPIE Proceedings Vol. 6427:
Optical Methods for Tumor Treatment and Detection: Mechanisms and Techniques in Photodynamic Therapy XVI
David Kessel, Editor(s)

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