Time-resolved fluorescence measurements for diffuse optical tomography using ultrafast time-correlated single photon counting

We develop a novel approach to infer depth information about a small fluorophore-filled inclusion immersed in a scattering medium. It relies on time-resolved measurements of the time of flight distribution of emitted fluorescent photons after short pulse laser excitation. The approach uses a novel numerical constant fraction discrimination technique to assign a stable arrival time to the distribution's early photons. Our experimental results show a linear relationship between these arrival times and the position of the inclusion. This approach will serve as a useful technique in fluorescence diffuse optical tomography.