Transmission versus reflectance spectroscopy for quantitation

Craig M. Gardner

doi:10.1117/1.JBO.23.1.018001

2 January 2018 Transmission versus reflectance spectroscopy for quantitation

Craig M. Gardner

Author Affiliations +

Journal of Biomedical Optics, Vol. 23, Issue 1, 018001 (January 2018). https://doi.org/10.1117/1.JBO.23.1.018001

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.

CC BY: © The Authors. Published by SPIE under a Creative Commons Attribution 4.0 Unported License. Distribution or reproduction of this work in whole or in part requires full attribution of the original publication, including its DOI.

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Craig M. Gardner "Transmission versus reflectance spectroscopy for quantitation," Journal of Biomedical Optics 23(1), 018001 (2 January 2018). https://doi.org/10.1117/1.JBO.23.1.018001

Received: 8 November 2017; Accepted: 8 December 2017; Published: 2 January 2018

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