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Journal of Biomedical Optics

Measurement of dye diffusion in scattering tissue phantoms using dual-wavelength low-coherence interferometry
Author(s): Trude Støren; Arne Røyset; Lars Othar Svaasand; Tore Lindmo
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Paper Abstract

We demonstrate low-coherence interferometry (LCI) for dye diffusion measurements in scattering tissue phantoms. The diffusion coefficient of a phthalocyanine dye in 1.5% agar gel containing scattering Intralipid was measured using a dual-wavelength interfero-meter. One wavelength was matched to the absorption peak of the dye at 675 nm. The other, 805 nm, was not affected by the dye, and was used to correct for varying sample scattering as a function of depth, assuming a constant ratio between scattering at the two wavelengths. The same wavelength dependence of scattering is assumed for the entire sample, but no a priori knowledge about the amount of scattering is needed. The dye diffusion coefficient was estimated by fitting a mathematical model of the interferometer signal to the measured LCI envelope. We compare results obtained using both a constant-scattering and a depth-resolved-scattering approach to determine the sample scattering. The presented method provides robust estimation of the diffusion coefficient when spatial resolution in determining the depth-resolved scattering is varied. Results indicate that the method is valid for samples having continuous spatial variations in the scattering coefficient over lengths as short as the coherence length of the probing light. The method allows in situ characterization of diffusion in scattering media.

Paper Details

Date Published: 1 January 2006
PDF: 9 pages
J. Biomed. Opt. 11(1) 014017 doi: 10.1117/1.2159000
Published in: Journal of Biomedical Optics Volume 11, Issue 1
Show Author Affiliations
Trude Støren, Norwegian Univ. of Science and Technology (Norway)
Arne Røyset, SINTEF (Norway)
Lars Othar Svaasand, Norwegian Univ. of Science and Technology (Norway)
Tore Lindmo, Norwegian Univ. of Science and Technology (Norway)

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