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Proceedings Paper

Effect of skin and fat layers on the spatial sensitivity profile of continuous wave diffuse reflectance near-infrared spectra
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Paper Abstract

In order to measure muscle physiological parameters such as pH and oxygen partial pressure (PO2) by continuous wave (CW) diffuse reflectance near-infrared spectroscopy (NIRS), light must penetrate through skin and subcutaneous fat layers overlying muscle. In this study, the effect of skin and subcutaneous fat layer and on the spatial sensitivity profile of CW diffuse reflectance near-infrared spectra is investigated through Monte Carlo simulations. The simulation model uses a semi-infinite medium consisting of skin, fat and muscle. The optical properties of each layer are taken from the reported optical data at 750 nm. The skin color is either Caucasian or Negroid and the fat thickness is varied from 0 ~ 20 mm. The spatial sensitivity profile, penetration depth, and sensitivity ratio as functions of optical fiber source-detector separation (SD, 2.5 mm, 5.0 mm, 10.0 mm, 20.0 mm, 30.0 mm and 40.0 mm), skin color and fat thicknesses are predicted by the simulations. It is shown that skin color only slightly influenced the spatial sensitivity profile, while the presence of the fat layer greatly decreased the detector sensitivity. It is also shown that probes with longer SD separations can detect light from deeper inside the medium. The simulation results are used to design a fiber optic probe which ensures that enough light is propagated inside the muscle in NIRS measurement on a leg with a fat layer of normal thickness.

Paper Details

Date Published: 11 November 2005
PDF: 9 pages
Proc. SPIE 6007, Smart Medical and Biomedical Sensor Technology III, 60070M (11 November 2005); doi: 10.1117/12.630683
Show Author Affiliations
Ye Yang, Univ. of Massachusetts Medical School (United States)
Michael A. Shear, Univ. of Massachusetts Medical School (United States)
Olusola O. Soyemi, Univ. of Massachusetts Medical School (United States)
Babs R. Soller, Univ. of Massachusetts Medical School (United States)


Published in SPIE Proceedings Vol. 6007:
Smart Medical and Biomedical Sensor Technology III
Brian M. Cullum; J. Chance Carter, Editor(s)

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