Time-dependent whole-body fluorescence tomography of probe bio-distributions in mice

We present a fast scanning fluorescence optical tomography system for imaging the kinetics of probe distributions through out the whole body of small animals. Configured in a plane parallel geometry, the system scans a source laser using a galvanometer mirror pair (tau(switch)similar to 1 ms) over flexible source patterns, and detects excitation and emission light using a high frame rate low noise, 5 MHz electron multiplied charge-coupled device (EMCCD) camera. Phantom studies were used to evaluate resolution, linearity, and sensitivity. Time dependent (delta(t)= 2.2 min.) in vivo imaging of mice was performed following injections of a fluorescing probe ( indocyanine green). The capability to detect differences in probe delivery route was demonstrated by comparing an intravenous injection, versus an injection into a fat pocket ( retro orbital injection). Feasibility of imaging the distribution of tumor-targeted molecular probes was demonstrated by imaging a breast tumor-specific near infrared polypeptide in MDA MB 361 tumor bearing nude mice. A tomography scan, at 24 hour post injection, revealed preferential uptake in the tumor relative to surrounding tissue. (C) 2005 Optical Society of America.