Deriving a set of representative optical coefficients from the literature: an illustrative statistical framework for Monte Carlo simulations applied to the human skin

SignificanceAccurate characterization of light propagation in biological tissues is essential for applications such as phototherapy, photodermatology, photobiomodulation, and photodiagnosis. Because many organs are stratified, Monte Carlo simulations require sets of optical coefficients–absorption (μa), reduced scattering (μs′), anisotropy factor (g), and refractive index (n)–in addition to tissue geometry, to model light transport in each tissue layer. However, published values of these coefficients often differ significantly for a given tissue and wavelength.AimThis work aims to address the challenge of selecting representative optical coefficients for Monte Carlo simulations by compiling and critically evaluating reported optical properties of human skin (Phototype III) and muscle as an illustrative example.ApproachPublished optical coefficients reported for selected visible and near-infrared wavelengths were analyzed and compared. A statistical framework was applied to derive representative sets of optical coefficients for different skin layers from heterogeneous literature data.ResultsThe analysis revealed substantial variability among reported optical coefficients. Representative sets of absorption, reduced scattering, anisotropy, and refractive-index values were derived for distinct skin layers and muscle at selected wavelengths.ConclusionsThe proposed framework provides a practical approach for deriving representative optical coefficients from heterogeneous literature data and highlights the importance of standardized, multilayered tissue models for accurate and reproducible light-dosimetry simulations.