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Journal of Biomedical Optics

Influence of shear rate on the optical properties of human blood in the spectral range 250 to 1100 nm
Author(s): Moritz Friebel; Jürgen Helfmann; Gerhard J. Müller; Martina C. Meinke
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Paper Abstract

The intrinsic optical parameters—absorption coefficient µa, scattering coefficient μa, anisotropy factor g, and effective scattering coefficient μs—are determined for human red blood cells of hematocrit 42.1% dependent on the shear rate in the wavelength range 250 to 1100 nm. Integrating sphere measurements of light transmittance and reflectance in combination with inverse Monte-Carlo simulation are carried out for different wall shear rates between 0 and 1000 s-1. Randomly oriented cells show maximal μa, μs, and μs values. Cell alignment and elongation, as well as the Fahraeus effect at increasing shear rates, lead to an asymptotical decrease of these values. The anisotropy factor shows this behavior only below 600 nm, dependent on absorption; above 600 nm, g is almost independent of shear rate. The decrease of μs is inversely correlated with the hemoglobin absorption. Compared to randomly oriented cells, aggregation reduces all parameters by a different degree, depending on the hemoglobin absorption. It is possible to evaluate the influence of collective scattering phenomena, the absorption within the cell, and the cell shape.

Paper Details

Date Published: 1 September 2007
PDF: 8 pages
J. Biomed. Opt. 12(5) 054005 doi: 10.1117/1.2799154
Published in: Journal of Biomedical Optics Volume 12, Issue 5
Show Author Affiliations
Moritz Friebel, Laser- und Medizin-Technologie GmbH, Berlin (Germany)
Jürgen Helfmann, Laser- und Medizin-Technologie GmbH, Berlin (Germany)
Gerhard J. Müller, Charité Universitätsmedizin Berlin (Germany)
Martina C. Meinke, Charité Universitätsmedizin Berlin (Germany)

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