A Source Model for Optical Diffusion Tomography

T Vilhunen, V Kolehmainen, M Vauhkonen, and J P Kaipio

Department of Applied Physics, University of Kuopio, P.O. Box 1627, FIN-70211 Kuopio, Finland, Tanja.Vilhunen@uku.fi

ABSTRACT

In this paper a source model for optical diffusion tomography is proposed. The light propagation is modelled with the radiative transfer equation (RTE) in the vicinity of the laser sources and the diffusion approximation (DA) is used elsewhere. The solution of the RTE is used to construct a Dirichlet boundary condition for the DA on a fictitious boundary within the object. This boundary condition constitutes an approximative distributed source model for the DA in the remaining area. The method was tested with 2D simulations. The results were compared with Monte Carlo simulations and finite- element method with a conventional diffusion approximation model. The simulations show that the method improves the accuracy of the forward model in the vicinity of the source.

Keywords Optical diffusion tomography, finite element method, radiative transfer equation, diffusion approximation