A pilot characterization of quantitative time-domain fluorescence diffuse optical tomography

Quantitative measurements of fluorescent parameters have merited great interest lately for near-infrared fluorescence diffuse optical tomography - the efficient small animal imaging tool. We present a two-dimensional image reconstruction method for time-domain fluorescence diffuse optical tomography, which employs the analytical solution to the Laplace-transformed time-domain photon-diffusion equation to construct the inverse model and introduces a pair of real-domain transform-factors to effectively separate the fluorescent yield and lifetime parameters from the algebraic reconstruction technique solutions to the resultant linear inversions. By use of a specifically designed a multi-channel time-correlated single photon counting system and a normalized Born formulation for the inversion, the proposed scheme in a circular domain is experimentally validated using small-animal-sized cylindrical phantoms that embed several fluorescent targets made from 1%-Intralipid solution and differently contrasting fluorescent agents, where the time-resolved excitation and fluorescence signals are measured on the boundary. The results show that the approach retrieves the positions and shapes of the targets with a reasonable accuracy and simultaneously achieve quantitative reconstruction of the fluorescent yield and lifetime.