Depth-recognizable time-domain fluorescence molecular tomography in reflectance geometry

Utilizing reflective photons could circumvent the penetration limit of FMT, enabling reconstruction of fluorescence distribution near the surface regard less of the object size and extending its applications to surgical navigation and so on. Therefore, a time-domain reflective fluorescence molecular tomography (TD-rFMT) is proposed. The system excites and detects the emission light from the same angle within a field of view of 5 cm. Because the detected intensities of targets depend strongly on the depth, the reconstruction of targets in deep regions would be evidently affected. Therefore, a fluorescence yield reconstruction method with depth regularization and a weighted separation reconstruction strategy for lifetime are developed to enhance the performance for deep targets. Through simulations and phantom experiments, TD-rFMT is proved capable of reconstructing fluorescence distribution within a 2.5-cm depth with accurate reconstructed yield, lifetime, and target position(s).