The determination ofin vivohuman tissue optical properties and absolute chromophore concentrations using spatially resolved steady-state diffuse reflectance spectroscopy

Abstract

A method is described for measuring optical properties and deriving chromophore concentrations from diffuse reflection measurements at the surface of a turbid medium. The method uses a diffusion approximation model for the diffuse reflectance, in combination with models for the absorption and scattering coefficients. An optical fibre-based set-up, capable of measuring nine spectra from 400 to 1050 nm simultaneously, is used to test the method experimentally. Results of the analyses of phantom and in vivo measurements are presented. These demonstrate that in the wavelength range from 600 to 900 nm, tissue scattering can be described as a simple power dependence of the wavelength and that the tissue absorption can be accurately described by the addition of water, oxy- and deoxyhaemoglobin absorption.

Near-Infrared Spectroscopy

“…NIRS is unable to differentiate between the signal attenuation from hemoglobin and myoglobin; the absorbency signals of these two chromophores overlap in the NIR range. Myoglobin is much less sensitive to tissue oxygenation than hemoglobin; therefore oxygen delivery must be greatly reduced before the myoglobin spectrum is affected (Doornbos et al, 1999;Ferrari et al, 2004).…”

A wireless handheld probe with spectrally constrained evolution strategies for diffuse optical imaging of tissue

“…(1) [23][24][25][26][27] Although the slope-based approach is widely used, it is highly sensitive to noise. Small errors in the measurement can lead to a large error in the slope obtained through a least squares fitting procedure.…”

Mapping the myoglobin concentration, oxygenation, and optical pathlength in heart ex vivo using near-infrared imaging

“…A light-scattering component, s xy ( ), at each pixel (x,y) may be described by a power function [32], [33] and [34], where n 1 according to Refs. [34], [35], [36] and [37]. Using a Taylor series, a first approximation of the may be represented by a linear function of wavelength:…”