Methods for local photon path length and optical properties estimation, based on measured and simulated diffuse reflectance within 2 mm from the light source, are proposed and evaluated <i>in vivo</i> on Caucasian human skin. The accuracy of the methods was good (2%–7%) for path length and reduced scattering but poor for absorption estimation. Reduced scattering and absorption were systematically lower in the fingertip than in the forearm skin (633 nm). A maximum intrasite and interindividual variation of ~35% in an average photon path length was found. The methodology was applied in laser Doppler flowmetry, where path-length normalization of the estimated perfusion removed the optical property dependency.
© 2003 Optical Society of America
(000.4430) General : Numerical approximation and analysis
(160.4760) Materials : Optical properties
(170.3340) Medical optics and biotechnology : Laser Doppler velocimetry
(170.3660) Medical optics and biotechnology : Light propagation in tissues
(290.7050) Scattering : Turbid media
Marcus Larsson, Henrik Nilsson, and Tomas Strömberg, "In vivo Determination of Local Skin Optical Properties and Photon Path Length by Use of Spatially Resolved Diffuse Reflectance with Applications in Laser Doppler Flowmetry," Appl. Opt. 42, 124-134 (2003)