SPIE Journal Paper | 22 January 2025
KEYWORDS: Tissues, Biological samples, Optical properties, Absorption, Integrating spheres, Scattering, Reflectivity, Skin, Optical spheres, Transmittance
SignificanceAccurate values of skin optical properties are essential for developing reliable computational models and optimizing optical imaging systems. However, published values show a large variability due to a variety of factors, including differences in sample collection, preparation, experimental methodology, and analysis.AimWe aim to explore the influence of storage conditions on the optical properties of the excised skin from 400 to 1100 nm.ApproachWe utilize a double integrating sphere system and inverse adding-doubling approach to determine absorption, μa, and reduced scattering, μs′, coefficients of the porcine dermis and subcutaneous fat before and after refrigeration, freezing, or flash freezing.ResultsOur findings indicate a small average change of −0.005, −0.003, and 0.002 mm−1 in μa for the dermis and 0.001, −0.003, and −0.008 mm−1 for the subcutaneous tissue after refrigeration, freezing, and flash freezing, respectively, with the most notable differences observed in the hemoglobin absorption region. The value of μs′ shows a negligible average change of −0.05, −0.001, and −0.02 mm−1 for the dermis, and 0.06, −0.1, and 0.03 mm−1 change for the subcutaneous tissue for refrigerated, frozen, and flash-frozen samples, respectively.ConclusionsThe results provide additional context for the variability of published values of optical parameters and enable informed selection of sample storage conditions for future measurements. In addition, the results discussed here can be used to improve study planning, particularly with regard to maximizing the use of finite samples that have been collected.
