Diffuse reflection spectra of biotissues in vivo and transmission and reflection coefficients for biotissues in vitro are measured over 300-800 nm. These data are used to determine the spectral absorption and scattering indices and the scattering anisotropy factor for stomach mucous membranes under normal and various pathological conditions (chronic atrophic and ulcerous defects, malignant neoplasms). The most important physiological (hemodynamic and oxygenation levels) and structural-morphological (scatterer size and density) parameters are also determined. The results of a morphofunctional study correlate well with the optical properties and are consistent with data from a histomorphological analysis of the corresponding tissues.Keywords: in vivo/in vitro tissues, pathology, spectrophotometry, diffuse reflection, absorption and scattering indices, scattering anisotropy factor, blood content, oxygenation, scatterer density and size.Introduction. In the development of new laser techniques in medicine, which require preliminary testing, exact information on the propagation of optical radiation in biological tissues is of primary importance. The propagation of light in tissue is determined by its optical parameters, specifically the absorption (μ a ) and scattering (μ s ) coefficients and the scattering anisotropy factor (g). Furthermore, these optical indices contain important information on the micro-and macrostructure of the medium being studied and its constituents, as well as on its physiological, morphological, and biochemical parameters, and are key factors in the solution of basic and applied problems in biotechnology [1][2][3][4][5].Determining the optical indices of biological tissues is an extremely time-consuming task because of the complicated structure of biotissues, themselves, and the variety of ways photons interact with them. Most biological objects, including plant and animal tissue, are optically turbid, randomly inhomogeneous media, for which the scattering index can be hundreds of times the absorption index [1-3]. Because of this, separating the contributions of absorption and scattering to the attenuation of the intensity of light becomes a very difficult problem.At present there are two approaches to studying the optical parameters of biological objects in steady-state spectroscopy: spatial probing and classical spectrophotometry. The first involves measuring the diffuse reflection coefficient with spatial resolution and analyzing the data in the approximation of a semi-infinite medium with a diffusion or P 3 -approximation for the radiative transfer equations [3,6]. The second approach involves measuring the optical transmission and reflection coefficients assuming media with finite thicknesses and solving the inverse problem for the radiative transfer equations in various numerical or analytical model approximations [1][2][3][4][5][6][7][8][9][10][11][12][13][14][15]. Although the experimental and theoretical approaches are well developed, these methods have a number of well-known and mutu...
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.
hi@scite.ai
10624 S. Eastern Ave., Ste. A-614
Henderson, NV 89052, USA
Copyright © 2024 scite LLC. All rights reserved.
Made with 💙 for researchers
Part of the Research Solutions Family.