Optical properties of porcine skin dermis between 900 nm and 1500 nm

The weak absorption of shortwave infrared light by skin tissues between 700 and 1500 nm offers an important window for diagnosis by optical means. The strong scattering of shortwave infrared light by the skin, however, presen ts a challenge to the modelling of light propagation through the skin and t he understanding of skin optics. We have measured the collimated and diffus e transmittance and diffuse reflectance of porcine skin dermis samples with in 30 h post-mortem Monte Carlo simulations have been performed to inversel y determine the absorption coefficient, scattering coefficient and anisotro py factor of the dermis samples in the spectral range from 900 to 1500 nm. We further analyse the sensitivity of the values of the parameters to the e xperimental errors and inverse calculation procedures. The state of the cel lular integrity of the skin samples following optical measurements was veri fied using transmission electron microscopy. These results were correlated to study post-mortem effects on the in vitro optical properties of porcine dermis. We concluded that for samples stored within crushed ice for up to 3 0 h post-mortem the wavelength dependence of optical properties of the derm is remains unchanged while the values of the parameters vary moderately due to modification of the water content of the tissue.