Scatter Correction of Transmission Near-Infrared Spectra by Photon Migration Data: Quantitative Analysis of Solids

Abstract

The scope of this work is a new methodology to correct conventional near-infrared (NIR) data for scattering effects. The technique aims at measuring the absorption coefficient of the samples rather than the total attenuation measured in conventional NIR spectroscopy. The main advantage of this is that the absorption coefficient is independent of the path length of the light inside the sample and therefore independent of the scattering effects. The method is based on time-resolved spectroscopy and modeling of light transport by diffusion theory. This provides an independent measure of the scattering properties of the samples and therefore of the path length of light. This yields a clear advantage over other preprocessing techniques, where scattering effects are estimated and corrected for by using the shape of the measured spectrum only. Partial least squares (PLS) calibration models show that, by using the proposed evaluation scheme, the predictive ability is improved by 50% as compared to a model based on conventional NIR data alone. The method also makes it possible to predict the concentration of active substance in samples with other physical properties than the samples included in the calibration model.

Application of Monte Carlo Simulation-Based Photon Migration for Enhanced Understanding of Near-Infrared (NIR) Diffuse Reflectance. Part II: Photon Radial Diffusion in NIR Chemical Images

“…(1) and (2) in Part I. 12 Second, due to the similarity between the predicted reduced scattering coefficients in the current study and reported results, 17,18 it was anticipated that the value of anisotropy factor used in the simulation was biased from its true value. According to Eqs.…”

In vivo optical characterization of human prostate tissue using near-infrared time-resolved spectroscopy

“…The technique has previously been used in various areas of biomedical optics. [35][36][37][38][39] The aim of the paper is to provide information on parameters of dosimetric importance, as well as to introduce timeresolved spectroscopy as a tool in PDT research. In particular, the aim is to achieve separate information on a and s Ј, as well as quantitative information on hemoglobin parameters.…”

Near-infrared photon time-of-flight spectroscopy of turbid materials up to 1400 nm

“…Prominent examples of these two related techniques include in vivo blood monitoring, 5,14,15 breast cancer diagnostics via detection of intrinsic tumor biomarkers, 7 studies of brain hemodynamics and cerebral oxygenation, 16,17 and diffuse optical tomography. 18 Emerging applications include calibration-free and quantitative analysis of pharmaceutical solids, 19 scatter correction of NIRS of pharmaceutical solids, 20 analysis, 21 as well as optical porosimetry ͑PTOFS in combination with gas sensing͒. 22 Until now, PTOFS has been limited to the spectral range below 1100 nm ͑i.e., above ϳ9100 cm −1 ͒.…”