Fundamental 3D FEM analysis of light propagation in head model toward 3D optical tomography

Human head has anatomically and optically layered structure (skin, skull, gray and white matters), so that light propagates 3-dimensionally in the head taking complicated paths. Revealing the light paths is necessarily required to solve inverse problems and realize 3-dimensional optical tomography. In order to simulate the intracephalic light propagation, computational model for 3-dimensional finite elements method (FEM) was constructed. It had a hemispherical geometry and a layered distribution of scattering and absorption coefficients. The model consisted of 12528 elements, and the dimension of model, scattering and absorption coefficients of each element were assigned according to those of neonatal head. Impulse source was assumed, and boundary and initial conditions were appropriately given. Time-dependent photon diffusion equation was solved for fluence rate. And 3-dimensional distribution of fluence rate and time-dependent light propagation were then obtained. Light paths between source and detectors were also calculated. These results were visualized using computer graphics techniques.© (1997) COPYRIGHT SPIE--The International Society for Optical Engineering. Downloading of the abstract is permitted for personal use only.