Proposal for a Skin Layer-Wise Decomposition Model of Spatially-Resolved Diffuse Reflectance Spectra Based on Maximum Depth Photon Distributions: A Numerical Study

In the context of cutaneous carcinoma diagnosis based on in vivo optical biopsy, Diffuse Reflectance (DR) spectra, acquired using a Spatially Resolved (SR) sensor configuration, can be analyzed to distinguish healthy from pathological tissues. The present contribution aims at studying the depth distribution of SR-DR-detected photons in skin from the perspective of analyzing how these photons contribute to acquired spectra carrying local physiological and morphological information. Simulations based on modified Cuda Monte Carlo Modeling of Light transport were performed on a five-layer human skin optical model with epidermal thickness, phototype and dermal blood content as variable parameters using (i) wavelength-resolved scattering and absorption properties and (ii) the geometrical configuration of a multi-optical fiber probe implemented on an SR-DR spectroscopic device currently used in clinics. Through histograms of the maximum probed depth and their exploitation, we provide numerical evidence linking the characteristic penetration depth of the detected photons to their wavelengths and four source–sensor distances, which made it possible to propose a decomposition of the DR signals related to skin layer contributions.

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Spatially-Resolved Multiply-Excited Autofluorescence and Diffuse Reflectance Spectroscopy: SpectroLive Medical Device for Skin In Vivo Optical Biopsy

Electronics ◽

10.3390/electronics10030243 ◽

2021 ◽

Vol 10 (3) ◽

pp. 243

Author(s):

Walter Blondel ◽

Alain Delconte ◽

Grégoire Khairallah ◽

Frédéric Marchal ◽

Amélie Gavoille ◽

...

Keyword(s):

Electromagnetic Compatibility ◽

Diffuse Reflectance ◽

Diffuse Reflectance Spectroscopy ◽

Optical Probe ◽

Optical Biopsy ◽

Light Sources ◽

Skin Carcinoma ◽

Excitation Light ◽

Spatially Resolved

This contribution presents the development of an optical spectroscopy device, called SpectroLive, that allows spatially-resolved multiply-excited autofluorescence and diffuse reflectance measurements. Besides describing the device, this study aims at presenting the metrological and safety regulation validations performed towards its aimed application to skin carcinoma in vivo diagnosis. This device is made of six light sources and four spectrometers for detection of the back-scattered intensity spectra collected through an optical probe (made of several optical fibers) featuring four source-to-detector separations (from 400 to 1000 µm). In order to be allowed by the French authorities to be evaluated in clinics, the SpectroLive device was successfully checked for electromagnetic compatibility and electrical and photobiological safety. In order to process spectra, spectral correction and metrological calibration were implemented in the post-processing software. Finally, we characterized the device’s sensitivity to autofluorescence detection: excitation light irradiance at the optical probe tip in contact with skin surface ranges from 2 to 11 W/m², depending on the light source. Such irradiances combined to sensitive detectors allow the device to acquire a full spectroscopic sequence within 6 s which is a short enough duration to be compatible with optical-guided surgery. All these results about sensitivity and safety make the SpectroLive device mature enough to be evaluated through a clinical trial that aims at evaluating its diagnostic accuracy for skin carcinoma diagnosis.

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Spatially resolved diffuse reflectance with laser Doppler imaging for the simultaneous in-vivo measurement of tissue perfusion and metabolic state

10.1117/12.388059 ◽

2000 ◽

Cited By ~ 3

Author(s):

Kevin R. Forrester ◽

Roxane Shymkiw ◽

John Tulip ◽

Craig Sutherland ◽

David Hart ◽

...

Keyword(s):

Diffuse Reflectance ◽

Tissue Perfusion ◽

Laser Doppler ◽

Doppler Imaging ◽

Laser Doppler Imaging ◽

Metabolic State ◽

In Vivo Measurement ◽

Spatially Resolved

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Spatially resolved spectroscopy for guiding margin delineation during human skin carcinomas resection: first clinical results on diffuse reflectance and autofluorescence spectra and in vivo skin optical properties

Biophotonics: Photonic Solutions for Better Health Care VI ◽

10.1117/12.2309516 ◽

2018 ◽

Cited By ~ 1

Author(s):

Prisca Rakotomanga ◽

Marine Amouroux ◽

Charles Soussen ◽

Frédéric Marchal ◽

Alain Delconte ◽

...

Keyword(s):

Optical Properties ◽

Human Skin ◽

Diffuse Reflectance ◽

Clinical Results ◽

Spatially Resolved ◽

Spatially Resolved Spectroscopy

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Modelling, Design and Validation of Spatially Resolved Reflectance Based Fiber Optic Probe for Epithelial Precancer Diagnostics

Applied Sciences ◽

10.3390/app10248836 ◽

2020 ◽

Vol 10 (24) ◽

pp. 8836

Author(s):

Pankaj Singh ◽

Prabodh Pandey ◽

Shivam Shukla ◽

Naren Naik ◽

Asima Pradhan

Keyword(s):

Fiber Optic ◽

Numerical Study ◽

Fiber Optic Probe ◽

Scattering Coefficients ◽

Spatially Resolved ◽

Fiber Optic Probes ◽

Diagnosis Of Cancer ◽

Optic Probe ◽

In Vivo Diagnosis

Fiber-optic probes are imperative for in-vivo diagnosis of cancer. Depending on the access to a diseased organ and the mutations one aims to sense, the probe designs vary. We carry out a detailed numerical study of the efficacy of the common probe geometries for epithelial cancer characterization based on spatially resolved reflectance data. As per the outcomes of this comparative study, a probe has been manufactured and using Monte Carlo look up table based inversion scheme, the absorption and scattering coefficients of the epithelium mimicking top layer have been recovered from noisy synthetic as well as experimental data.

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