Optical Properties of Skin, Subcutaneous, and Muscle Tissues: A Review (original) (raw)
Related papers
Journal of Biomedical …, 1999
We investigated the impact of the scattering phase function approximation on the optical properties of whole human blood determined from integrating sphere measurements using an inverse Monte Carlo technique. The diffuse reflectance R d and the total transmittance T t (ϭ633 nm) of whole blood samples (Hctϭ38%) were measured with double-integrating sphere equipment. The scattering phase functions of highly diluted blood samples (Hctϭ0.1%) were measured using a goniophotometer. We approximated the experimentally determined scattering phase functions with either Henyey-Greenstein (HGPF), Gegenbauer kernel (GKPF), or Mie (MPF) phase functions to preset the anisotropy factor for the inverse problem. We have employed HGPF, GKPF, and MPF approximations in the inverse Monte Carlo procedure to derive the absorption coefficient a and the scattering coefficient s. To evaluate the obtained data, we calculated the angular distributions of scattered light for optically thick samples and compared the results with goniophotometric measurements. The data presented in this study demonstrate that the employed approximation of the scattering phase function can have a substantial impact on the derived values of s and , while a and the reduced scattering coefficient s Ј are much less sensitive to the exact form of the scattering phase function.
Study of Scattering and Polarization of Light in Biological Tissues
2013
INTRODUCTION 1.1 State of-the-art 1.2 Objectives of the dissertation 2 SELECTED METHODS OF INVESTIGATION 2.1 Modeling of photon transport in tissue 9 2.1.1 Radiative transfer equation 3 EXPERIMENTAL RESULTS 3.1 Stokes vector polarimeter 3.2 Monte Carlo analysis of multiscattered light 3.2.1 Intensity and degree of polarization 3.2 Ageing process 4 CONCLUSION 5 REFERENCES
Determination of reduced scattering coefficient of biological tissue from a needle-like probe
Optics Express, 2005
Detection of interactions between light and tissue can be used to characterize the optical properties of the tissue. The purpose of this paper is to develop an algorithm that determines the reduced scattering coefficient (μ s ') of tissues from a single optical reflectance spectrum measured with a small source-detector separation. A qualitative relationship between μ s ' and optical reflectance was developed using both Monte Carlo simulations and empirical tissue calibrations for each of two fiber optic probes with 400-μm and 100-μm fibers. Optical reflectance measurements, using a standard frequency-domain oximeter, were performed to validate the calculated μ s ' values. The algorithm was useful for determining μ s ' values of in vivo human fingers and rat brain tissues.
Characteristics of light scattering by normal and modified areas of skin tissue
Journal of Applied Spectroscopy, 2011
Results from numerical calculations and experimental studies of the optical backscattering coefficients and changes in the polarization characteristics of normal and modified (birthmark, scar) skin tissue structures are presented. It is shown that determining the Mueller matrix is an effective way of detecting changes in the structure of skin tissue in vivo which reflects changes in the depolarization of light by an object for different polarization parameters of the incident (probe) radiation. The depolarization of light is found to be symmetric for normal areas of skin and antisymmetric for skin tissue with a modified structure. It is proposed that the polarization characteristics of scattered radiation be used in detecting damaged areas of skin tissue.
Shedding the Polarized Light on Biological Tissues, 2021
Any physical object or medium is a complex, optically heterogeneous, structure. Such heterogeneity is characterized by the spatial distributions of the overall optical parameters (refractive indices and absorption) and their anisotropic components (linear and circular birefringence, linear and circular dichroism). In addition, there can be spatial and/or angular heterogeneity of the orientation, size, shape, and volume of the particles or domains constituting the overall physical body at the micro-and macrolevels [1-6]. A common feature of such optically heterogeneous objects is scattering of incident light. This scattering is the subject of optics of scattering media. Light interacting with biological objects is therefore scattered by biological structures. These can include various biological fluids (blood, lymph, cerebrospinal fluid, urine, bile, etc.) and tissues (muscle, connective, epithelial, nervous). All these biological objects typically exhibit multiple scattering and form optically turbid layers [7, 8]. The optical properties of such objects within the photometric approximation are described by the model of multiple scattering of scalar waves in a randomly inhomogeneous medium with absorption [1, 5-9]. If the optical thickness of a biological layer is insignificant (weakly or singly scattering media), then its properties with respect to light intensity conversion are traditionally determined with a model of single scattering within an ordered medium with densely packed scattering centers [10]. From the point of view of the geometric construction of such optically inhomogeneous layers, one can distinguish surface or rough scattering [10-12], as well as volume scattering [13-15]. Historically, there are three main approaches to the studies of the optical properties of such biological objects-1) spectrophotometric, that is based on the analysis of spatial or temporal changes in the intensity of scattered radiation in the optical range of electromagnetic wavelengths [16-19]; 2) polarimetric, based on the analysis of the distributions of the azimuth and polarization elliptic distributions, or the degree
Angular distribution of diffuse reflectance in biological tissue
Applied Optics, 2007
We measured angular-resolved diffuse reflectance in tissue samples of different anisotropic characteristics. Experimental measurements were compared with theoretical results based on the diffusion approximation. The results indicated that the angular distribution in isotropic tissue was the same as in isotropic phantoms. Under normal incidence, the measured angular profiles of diffuse reflectance approached the Lambertian distribution when the evaluation location was far away from the incident point. The skewed angular profiles observed under oblique incidence could be explained using the diffuse model. The anisotropic tissue structures in muscle showed clear effects on the measurements especially at locations close to the light incidence. However, when measuring across the muscle fiber orientations, the results were in good agreement with those obtained in isotropic samples.
Light Scattering Applied to the Study of Biological Tissues: To an Optical Biopsy
2018
This work is devoted to the study of light scattering in biological tissues. It aims to determine indicators that permit to differentiate between cancerous and normal tissues of a human organ and to seek a mean of therapy transport. For this, we analyzed the intensity and the spectral variation of the scattered light as a function of its scattering direction. This work gives some main results of the experiment and the simulation. We stepped impressive to discriminate between cancerous and normal tissues of a human organ, such as: Vesicle, Breast.
Re-evaluation of model-based light-scattering spectroscopy for tissue spectroscopy
Journal of Biomedical Optics, 2009
Model-based light scattering spectroscopy (LSS) seemed a promising technique for in-vivo diagnosis of dysplasia in multiple organs. In the studies, the residual spectrum, the difference between the observed and modeled diffuse reflectance spectra, was attributed to single elastic light scattering from epithelial nuclei, and diagnostic information due to nuclear changes was extracted from it. We show that this picture is incorrect. The actual single scattering signal arising from epithelial nuclei is much smaller than the previously computed residual spectrum, and does not have the wavelength dependence characteristic of Mie scattering. Rather, the residual spectrum largely arises from assuming a uniform hemoglobin distribution. In fact, hemoglobin is packaged in blood vessels, which alters the reflectance. When we include vessel packaging, which accounts for an inhomogeneous hemoglobin distribution, in the diffuse reflectance model, the reflectance is modeled more accurately, greatly reducing the amplitude of the residual spectrum. These findings are verified via numerical estimates based on light propagation and Mie theory, tissue phantom experiments, and analysis of published data measured from Barrett's esophagus. In future studies, vessel packaging should be included in the model of diffuse reflectance and use of model-based LSS should be discontinued.
Tissue scattering parameter estimation through scattering phase function measurements by goniometer
2007
An automated optical system is built up to perform goniometric measurement of scattering phase function. Measurements of typical samples including monodisperse polystyrene micro-spheres solution, and mutlidisperse polystyrene micro-spheres solution are carried out in a dark room. The possibility of estimating the average particle size of phantom through analyzing its scattering phase function is demonstrated.