scholarly journals Analysis of spectroscopic diffuse reflectance plots for different skin conditions

2010 ◽  
Vol 24 (5) ◽  
pp. 467-481 ◽  
Author(s):  
Shanthi Prince ◽  
S. Malarvizhi
Keyword(s):  
Diffuse Reflectance ◽  
Near Infrared ◽  
Skin Diseases ◽  
Diffuse Reflectance Spectroscopy ◽  
Spectral Characteristics ◽  
Reflectance Spectra ◽  
Diffuse Reflectance Spectra ◽  
Spectral Curves ◽  
Skin Conditions

Optical means of characterizing tissues have gained importance due to its noninvasive nature. Spectral characteristics of the components provide useful information to identify the components, because different chromophores have different spectroscopic responses to electromagnetic waves of a certain energy band. The purpose of this study is to determine whether visible/near-infrared diffuse reflectance spectroscopy can be used to non-invasively characterize skin diseasesin vivo.An optical fiber spectrometer is set up for obtaining diffuse reflectance spectra. The method involves exposure of skin surface to white light produced by an incandescent source. The back scattered photons emerging from various layers of tissue are detected by spectrometer resulting in diffuse reflectance spectra.For the present study different skin conditions like – warts, vitiligo, thrombus (due to injury) and angioma are chosen. The spectral data obtained from the scan are plotted and compared. More or less, the shapes of the spectral curves for various skin conditions resemble. In order to characterize and differentiate different diseased state spectral analysis based on Ratio analysis, Student'st-tests and difference plot are carried out.Based on the analysis the relative spectral intensity changes are quantified and the spectral shape changes are enhanced and more easily visualized on the spectral curves, thus assisting in differentiating the normal tissue from the one affected by disease.

Diffuse-Reflectance Spectra of Rare-Earth Oxides

1967 ◽  
Vol 21 (3) ◽  
pp. 167-171 ◽  
Author(s):  
William B. White
Keyword(s):  
Rare Earth ◽  
Diffuse Reflectance ◽  
Near Infrared ◽  
Diffuse Reflectance Spectroscopy ◽  
Rare Earth Oxides ◽  
Rare Earth Ions ◽  
Reflectance Spectra ◽  
Solid Materials ◽  
Diffuse Reflectance Spectra ◽  
Structural Types

Diffuse-reflectance spectra are reported for 11 rare-earth oxides of various structural types over the spectral range of 225–2700 mμ. These spectra, particularly in the near infrared, permit the use of diffuse-reflectance spectroscopy to identify rare-earth ions in solid materials.

scholarly journals Suitability of diffusion approximation for an inverse analysis of diffuse reflectance spectra from human skin in vivo

OSA Continuum ◽  
2019 ◽  
Vol 2 (3) ◽  
pp. 905 ◽  
Author(s):  
Peter Naglič ◽  
Luka Vidovič ◽  
Matija Milanič ◽  
Lise L. Randeberg ◽  
Boris Majaron
Keyword(s):  
Human Skin ◽  
Diffusion Approximation ◽  
Inverse Analysis ◽  
Diffuse Reflectance ◽  
Reflectance Spectra ◽  
Diffuse Reflectance Spectra

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.

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