Optical simulations of skin diagnosis with account of multiple surface scattering events

摘要

Abstract: To fully exploit current optical methods of skin diagnosis, it is desirable to understand the physics underlying photon migration in epithelial tissue. A number of approaches have been developed to meet this challenge. Most simulations are based upon the radiative transport theory which describes the sequential transfer of diffuse light through the stack of skin layers. These models are computationally intensive and typically rely upon the following assumptions: (1) volume scattering of photons inside the collagen fiber layer is predominant, (2) photons undergo Fresnel reflections on each boundary, (3) scattering can be modeled along each path using prescribed phase functions such as Henyey-Greenstein or Mie. Our work simulates photon migration in skin from a different standpoint: using a commercially available optics code, we randomly trace a large number of photons and assign generic absorption and scattering properties to all boundaries, including the ones separating sublayers of collagen fibers. As a result, single and multiple surface scattering events are account for. Absorbing inhomogeneities may be included as light obstructions and fluorophores as secondary sources, respectively. This preliminary work is targeted for clinical applications involving skin imaging and spectroscopy.!8