Research on the relationship between diffuse reflectance of tissue and its optical parameters

2004 ◽  
Author(s):  
Shuying Cheng ◽  
Hongyuan Shen
Keyword(s):  
Diffuse Reflectance ◽  
Optical Parameters ◽  
The Relationship

Analytical Solution to the Depth-of-Origin Profile of Transmission Raman Spectroscopy in Turbid Media Based on the Kubelka–Munk Model

2019 ◽  
Vol 73 (9) ◽  
pp. 1061-1073
Author(s):  
Jun Zhao
Keyword(s):  
Raman Spectroscopy ◽  
Analytical Formula ◽  
Turbid Media ◽  
Optical Parameters ◽  
Direct Measurements ◽  
Model Sample ◽  
Transmission Raman ◽  
The One ◽  
The Relationship ◽  
Better Than

An analytical formula to the depth-of-origin profile of transmission Raman spectroscopy in turbid media was derived from the one-dimensional (1D) Kubelka–Munk model. The depth-of-origin profile of the transmitted Raman is proportional to the excitation intensity profile and the transmittance profile, which are two functions of similar forms. The effect of scattering, absorption, and signal-enhancing reflectors are incorporated into the formula. Depth-of-origin profile of a model sample was measured at better than 0.2 mm resolution and fits the formula reasonably well. Conical reflective cavities placed at the front and/or back of the sample enhanced the signal significantly; the relationship among the enhancement functions is verified by the formula. Optical parameters derived from the fitting are compared to theoretical value predicted by optical ray tracing and direct measurements; discrepancies are related to deficiency of the 1D Kubelka–Munk model.

scholarly journals Validation of an Inverse Fitting Method of Diffuse Reflectance Spectroscopy to Quantify Multi-Layered Skin Optical Properties

Photonics ◽  
2019 ◽  
Vol 6 (2) ◽  
pp. 61 ◽  
Author(s):  
Chiao-Yi Wang ◽  
Tzu-Chia Kao ◽  
Yin-Fu Chen ◽  
Wen-Wei Su ◽  
Hsin-Jou Shen ◽  
...  
Keyword(s):  
Optical Properties ◽  
Diffuse Reflectance ◽  
Volume Fraction ◽  
Diffuse Reflectance Spectroscopy ◽  
Reflectance Spectra ◽  
In Vivo Studies ◽  
Process Time ◽  
Optical Parameters ◽  
Fitting Procedure

Skin consists of epidermis and dermis layers that have distinct optical properties. The quantification of skin optical properties is commonly achieved by modeling photon propagation in tissue using Monte Carlo (MC) simulations and iteratively fitting experimentally measured diffuse reflectance spectra. In order to speed up the inverse fitting process, time-consuming MC simulations have been replaced by artificial neural networks to quickly calculate reflectance spectra given tissue geometric and optical parameters. In this study the skin was modeled to consist of three layers and different scattering properties of the layers were considered. A new inverse fitting procedure was proposed to improve the extraction of chromophore-related information in the skin, including the hemoglobin concentration, oxygen saturation and melanin absorption. The performance of the new inverse fitting procedure was evaluated on 40 sets of simulated spectra. The results showed that the fitting procedure without knowing the epidermis thickness extracted chromophore information with accuracy similar to or better than fitting with known epidermis thickness, which is advantageous for practical applications due to simpler and more cost-effective instruments. In addition, the melanin volume fraction multiplied by the thickness of the melanin-containing epidermis layer was estimated more accurately than the melanin volume fraction itself. This product has the potential to provide a quantitative indicator of melanin absorption in the skin. In-vivo cuff occlusion experiments were conducted and skin optical properties extracted from the experiments were comparable to the results of previously reported in vivo studies. The results of the current study demonstrated the applicability of the proposed method to quantify the optical properties related to major chromophores in the skin, as well as scattering coefficients of the dermis. Therefore, it has the potential to be a useful tool for quantifying skin optical properties in vivo.

scholarly journals Oblique-incidence reflectometry: one relative profile measurement of diffuse reflectance yields two optical parameters

1995 ◽  
Author(s):  
Lihong V. Wang ◽  
Shao-Pow Lin ◽  
Steven L. Jacques ◽  
Frank K. Tittel ◽  
Jennifer Harder ◽  
...  
Keyword(s):  
Oblique Incidence ◽  
Diffuse Reflectance ◽  
Profile Measurement ◽  
Optical Parameters

Diffuse Reflectance Parameters of Treated Leishmaniasis Cutaneous Ulcers and Association with Histopathologies in an Animal Model: A Proof of Concept

2021 ◽  
pp. 247263032110302
Author(s):  
Lina Restrepo ◽  
Javier Murillo ◽  
Deivid Botina ◽  
Artur Zarzycki ◽  
Johnson Garzón ◽  
...  
Keyword(s):  
Diffuse Reflectance ◽  
Healing Process ◽  
Inverse Correlation ◽  
Polymorphonuclear Neutrophils ◽  
Optical Parameters ◽  
Proof Of Concept ◽  
Scattering Parameter ◽  
Scattering Coefficients ◽  
Skin Ulcers ◽  
Chronic Skin

Cutaneous leishmaniasis (CL) is a parasitic disease that produces chronic skin ulcers. Although it has a worldwide presence, it is a neglected disease that still requires novel tools for its management. In order to study the use of optical tools in CL, this article presents a preliminary study of the correlation between CL histopathological and optical parameters. Optical parameters correspond to absorption and scattering coefficients obtained from diffuse reflectance spectra of treated CL in golden hamsters. Independently, histopathological data were collected from the same hamsters. As a result, after Spearman correlation and the Kruskal–Wallis test, inverse correlation was found between absorption/scattering optical parameters and inflammatory histopathological values, such as the scattering parameter related to the diameter of fibroblasts with the histopathological parameters of fibrosis, polymorphonuclear neutrophils, lymphocytes, plasmocytes, hyperplasia, and Leishmania, and the absorption parameter oxygen saturation showed a relation with the granulation tissue histopathological parameter. These correlations agree with the expected behavior of tissue composition during the healing process in CL. The results correspond to a proof of concept that shows that optical diffuse reflectance-based tools and methods could be considered as an alternative to assist in CL diagnosis and treatment follow-up.

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