Fluorescence lifetime imaging with measurements of photon migration: theory, simulation, and experiment

Frequency-domain measurements of photon migration are coupled with a model of fluorescence generation and propagation in order to develop a method for reconstructing maps of fluorescent properties within interior tissue volumes from exterior measurements at the air-tissue interface. Simulated results confirm the feasibility of optical imaging through the use of exogenously administered contrast agents on the basis of fluorophore decay kinetics and yield. Experimental measurements using single-pixel and multi-pixel devices illustrate that the contrast from exogenous fluorescence exceeds that owing to absorption or scattering caused by endogenous chromophores or tissue structure and owing to absorption caused by exogenous contrast agents. The prognosis for fluorescence lifetime imaging as a prognostic imaging modality is discussed.