Shedding light on the variability of optical skin properties: finding a path towards more accurate prediction of light propagation in human cutaneous compartments

Abstract

Abstract:Finding a path towards a more accurate prediction of light propagation in human skin remains an aspiration of biomedical scientists working on cutaneous applications both for diagnostic and therapeutic reasons. The objective of this study was to investigate variability of the optical properties of human skin compartments reported in literature, to explore the underlying rational of this variability and to propose a dataset of values, to better represent an in vivo case and recommend a solution towards a more accurate prediction of light propagation through cutaneous compartments. To achieve this, we undertook a novel, logical yet simple approach. We first reviewed scientific articles published between 1981 and 2013 that reported on skin optical properties, to reveal the spread in the reported quantitative values. We found variations of up to 100-fold. Then we extracted the most trust-worthy datasets guided by a rule that the spectral properties should reflect the specific biochemical composition of each of the skin layers. This resulted in the narrowing of the spread in the calculated photon densities to 6-fold. We conclude with a recommendation to use the identified most robust datasets when estimating light propagation in human skin using Monte Carlo simulations. Alternatively, otherwise follow our proposed strategy to screen any new datasets to determine their biological relevance.

Hyperspectral characterization of re‐epithelialization in an in vitro wound model

“…The ability of the hyperspectral system to sense changes in the wounds is dependent on the ability of these changes to influence the reflectance. The reflectance is determined by the optical properties of the tissue, which is typically modeled as a multilayer structure with absorption and scattering coefficients μ a (λ) and μ s (λ) in each layer [28][29][30][31].…”

Quantification and influence of skin chromophores for remote detection of anemic conditions

“…In the study by Salomatina et al (2006), 25 sample preparation (rinsing with PBS and rehydration with saline solution) for measurement of optical properties is speculated to cause the underestimation of the values. 8 Therefore, the values reported by Altshuler et al 24 are reasoned to be the best fit for this current study. Contributing to this choice is also the fact that these values were extended from the widely accepted empirical relationship 26 into the near-infrared region.…”

“…However, the blood and water absorption peaks were missing and absorption was overestimated while the scattering was underestimated. 8 Similarly, there is a continuing debate about the variability and applicability of optical properties. In the many techniques of sample preparation and optical measurements, there is a 100fold variability in the reported optical property values.…”

“…In the many techniques of sample preparation and optical measurements, there is a 100fold variability in the reported optical property values. 8 After screening the optical properties, a subset of the values are analyzed using MC methods and compared to standards from the National Institute of Standards and Technology (NIST). This method of screening the optical properties' values was done in our current study and is discussed in Section 3.…”

Introduction to Photonics: Principles and the Most Recent Applications of Microstructures

“…Photonics is essentially the science that involves generation of a photon (light), its detection, as well as manipulation via transmission, emission, signal processing, modulation, switching, amplification, and sensing. Most importantly, photonics involves the proper use of light as a tool for the benefit of humans [ 2 , 3 ]. Most photonics applications, even though they cover all technical applications over the entire electromagnetic spectrum, range from near-infrared light to visible region.…”