Absorption and reduced scattering coefficient estimation in pigmented human skin tissue by experimental colorimetric...

Area of Science:

• Biomedical Optics
• Photomedicine
• Dermatology

Background:

• Accurate optical properties of human skin are crucial for light-based therapies.
• Melanin content significantly influences skin's optical properties, varying with skin type.
• Existing models often require complex measurements, limiting clinical applicability.

Purpose of the Study:

• To develop a simplified model for estimating skin's absorption (μa) and reduced scattering (μs') coefficients.
• To correlate these optical properties with the Individual Typology Angle (ITA) derived from skin color.
• To provide a tool for predicting therapeutic light penetration based on skin type.

Main Methods:

• Human skin samples were grouped by ITA and measured using a colorimeter.
• An integrating sphere and inverse adding-doubling algorithm computed μa and μs'.
• Mathematical models were developed to correlate optical properties with ITA and wavelength.

Main Results:

• Absorption coefficient (μa) increases as ITA decreases (darker skin).
• Reduced scattering coefficient (μs') was independent of ITA but dependent on wavelength.
• Developed equations showed high agreement with experimental data (R² > 0.93).

Conclusions:

• An experimental model accurately estimates ex vivo human skin's optical properties using ITA.
• This model simplifies predicting light absorption and scattering based on skin color.
• Findings are relevant for optimizing photobiomodulation and light treatments by accounting for melanin variations.