In this work, light propagation in a scattering medium with piece-wise constant refractive index using the radiative transport equation was studied. Light propagation in each sub-domain with a constant refractive index was modeled using the RTE and the equations were coupled using boundary conditions describing Fresnel reflection and transmission phenomenas on the interfaces between the sub-domains. The resulting coupled system of RTEs was numerically solved using the FEM. The proposed model was tested using simulations and was compared with the solution of the Monte Carlo method. The results show that the coupled RTE model describes light propagation accurately in comparison with the Monte Carlo method. In addition, results show that neglecting internal refractive index changes can lead to erroneous boundary measurements of scattered light. This indicates that the quality of the DOT reconstructions could possible be increased by incorporating a model for internal refractive index changes in the image reconstruction procedure.
