Fluorescence Molecular Tomography using quantitative photonic and photo-acoustic measurements

We here present a novel expression for the photo-acoustic contribution of an optical point source in a diffusive and absorbing medium. By using this measurement as a reference, we present a direct inversion formula that recovers the absorption map quantitatively, at the same time eliminating instrumental factors such as the source strength, the shape of the optical pulse and the impulse response and finite size of the transducers. We further validate this expression through accurate numerical simulations showing that the absorption map is recovered quantitatively in the presence of a point source. The derivation of solutions for point sources within the photo-acoustic problem enables the use of concurrent fluorescence and ultrasound measurements as appropriate for a hybrid tomographic system. This system could retrieve absorption information using photo-acoustic measurements, and use this data to more accurately describe the fluorescence problem and improve reconstruction fidelity.