Experimental results using a three-layer skin model for diffuse reflectance spectroscopy
2013 (English)In: Optical Tomography and Spectroscopy of Tissue X / [ed] Bruce J. Tromberg, Arjun G. Yodh, Eva M. Sevick-Muraca, SPIE - International Society for Optical Engineering, 2013, 857834-1-857834-8 p.Conference paper (Other academic)
We have previously presented an inverse Monte Carlo algorithm based on a three-layer semi-infinite skin model for analyzing diffuse reflectance spectroscopy (DRS) data. The algorithm includes pre-simulated Monte Carlo data for a range of physiologically relevant epidermal thicknesses and tissue scattering levels. The simulated photon pathlength distributions in each layer are stored and the absorption effect from tissue chromophores added in the post-processing. Recorded DRS spectra at source-detector distances of 0.4 and 1.2 mm were calibrated for the relative intensity between the two distances and matched to simulated spectra in a non-linear optimization algorithm. This study evaluates the DRS spectral fitting accuracy and presents data on the main output parameters; the tissue fraction of red blood cells and local oxygenation (SO2). As a reference, the microcirculatory perfusion (Perf) was measured simultaneously in the same probe using laser Doppler Flowmetry. Data were recorded on the volar forearm of three healthy subjects in a protocol involving a 5 min systolic occlusion. The DRS spectra were modeled with an rms-error < 2%. In two subjects, SO2 decreased during occlusion to <10%, and increased to above baseline after hyperemia, while Perf increased >7 times compared to baseline. In the third subject the SO2 decreased less during occlusion and increased to baseline values at hyperemia with only a 2-fold increase in Perf. The observed difference could be due to different microvascular beds being probed. It is concluded that integrating DRS and LDF enables new possibilities to deduce microcirculation status.
Place, publisher, year, edition, pages
SPIE - International Society for Optical Engineering, 2013. 857834-1-857834-8 p.
, Proceedings of SPIE, ISSN 0277-786X, EISSN 1996-756X ; 8578
Microcirculation, diffuse reflectance spectra, Monte Carlo simulations, skin modeling, laser Doppler flowmetry
Medical Laboratory and Measurements Technologies
IdentifiersURN: urn:nbn:se:liu:diva-97046DOI: 10.1117/12.2014323ISBN: 9780819493477OAI: oai:DiVA.org:liu-97046DiVA: diva2:645355
Optical Tomography and Spectroscopy of Tissue X, 2 February 2013, San Francisco, California, USA