The finite-element method for the propagation of light in scattering media: frequency domain case

A frequency domain light transport model to simulate the transillumination of a scattering object with radio frequency intensity modulated light is presented. The model is based on the diffusion approximation to the radiative transfer equation and uses a finite-element model to allow for complex geometries and an inhomogeneous distribution of absorption and scattering. It calculates the complex photon density within the object and the complex exitance on the boundary of the object. The model is validated against an analytic Green's function model for a circular geometry in the homogeneous case, and its accuracy is investigated for a range of mesh resolutions, optical parameters, and modulation frequencies.