Analysis of Light Transmission in Skin Tissue Considering Scattering Condition in Beer-Lambert Type Models

In this work, we present an analysis of light transmission of the Beer-Lambert Theory using a multilayer skin model for oximetry applications that considers a system of different layers of skin (dermis and epidermis) containing physical properties of whole blood as a suspension of erythrocytes in plasma. Erythrocytes are assumed with hemoglobin inside in its oxygenated and deoxygenated form according to the oxygen saturation. Due to the non-homogeneity of the skin, the Beer-Lambert law is extended for a suspension of erythrocytes in plasma considering: (i) its absorption cross-section and (ii) its absorption and scattering cross-sections. The obtained results proof that the scattering is stronger than the absorption in a spectral range from 350 to 1000 nm. Likewise, the scattering in this model is presented as forward scattering, giving a slight difference to the Beer-Lambert model of homogeneous medium respect to the extended models of inhomogeneous medium analyzed. These analytic models can be a simple way for interpreting experiments based in oximetry.