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Journal of Biomedical Optics • Open Access

Transmission versus reflectance spectroscopy for quantitation
Author(s): Craig M. Gardner

Paper Abstract

The objective of this work was to compare the accuracy of analyte concentration estimation when using transmission versus diffuse reflectance spectroscopy of a scattering medium. Monte Carlo ray tracing of light through the medium was used in conjunction with pure component absorption spectra and Beer–Lambert absorption along each ray’s pathlength to generate matched sets of pseudoabsorbance spectra, containing water and six analytes present in skin. PLS regression models revealed an improvement in accuracy when using transmission compared to reflectance for a range of medium thicknesses and instrument noise levels. An analytical expression revealed the source of the accuracy degradation with reflectance was due both to the reduced collection efficiency for a fixed instrument etendue and to the broad pathlength distribution that detected light travels in the medium before exiting from the incident side.

Paper Details

Date Published: 2 January 2018
PDF: 8 pages
J. Biomed. Opt. 23(1) 018001 doi: 10.1117/1.JBO.23.1.018001
Published in: Journal of Biomedical Optics Volume 23, Issue 1
Show Author Affiliations
Craig M. Gardner, Tru Touch Technologies Inc. (United States)

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