DIRECT CALCULATION WITH A FINITE-ELEMENT METHOD OF THE LAPLACE TRANSFORM OF THE DISTRIBUTION OF PHOTON TIME-OF-FLIGHT IN TISSUE

Reconstruction methods for optical tomographic imaging require the dev elopment of models of light transport in highly scattering materials. While the simulation of the full temporal response function arising fr om a short source Light pulse is computationally expensive, there are methods to evaluate efficiently certain transforms of the temporal pro file. We previously presented methods to obtain directly the Mellin tr ansform, which is related to the moments of the temporal intensity dis tribution; We introduce a similar method to calculate directly the Lap lace transform. This method provides an additional, largely independen t measurement type that can be combined with the moments to improve im age quality in optical tomography, in particular with respect to the s imultaneous reconstruction of absorption and scattering distributions. (C) 1997 Optical Society of America.