Simultaneous mapping of absorption and scattering coefficients from a three-dimensional model of time-resolved optical tomography

A Newton-Raphson inversion algorithm has been extended for simultaneous abs orption and scattering reconstruction of fully three-dimensional (3D) diffu se optical tomographic imaging from time-resolved measurements. The propose d algorithm is derived from the efficient computation of the Jacobian matri x of the forward model and uses either the algebraic reconstruction techniq ue or truncated singular-value decomposition as the linear inversion tool. Its validation was examined with numerically simulated data from 3-D finite -element discretization models of tissuelike phantoms, with several combina tions of geometric and optical properties, as well as two commonly used sou rce-detector configurations. Our results show that the fully 3-D image reco nstruction of an object can be achieved with reasonable quality when volume tric light propagation in tissues is considered, and temporal information f rom the measurements can be effectively employed. Also, we investigated the conditions under which 3-D issues could be approximately addressed with tw o-dimensional reconstruction algorithms and further demonstrated that these conditions are seldom predictable or attainable in practice. Thus the appl ication of 3-D algorithms to realistic situations is necessary. (C) 2000 Op tical Society of America OCIS codes: 170.6920, 170.3010, 100.3190.