Simulation study on penetration depth of light in the source–detector distance using a nine-layered skin tissue model in the visible wavelength range

We simulated the relationship between the diffuse reflectance and penetration depth of light in skin with respect to the source (S)–detector (D) distance using the nine-layered skin tissue model for three wavelengths in the visible range. The photon propagation trajectory is visualized for intuitive understanding. The average penetration depth and the diffuse reflectance component are graphically related with the S-D distance. The results of the penetration depth versus diffuse reflectance and comparison with multiple regression analysis indicate that changes of absorption and/or scattering in the upper dermis region are expected to be perceived selectively.