An overview of time-domain diffuse fluorescence imaging: instrumentation and applications

Rapidly pulsed laser excitation with high-rate signal detection allows the dispersion of emitted fluorescent signals through tissue to be measured. This “time-domain” approach to measuring diffuse fluorescence data offers a wide range of advantages over conventional “continuous-wave” fluorescence imaging. While continuous-wave imaging provides a measure of only fluorescence intensity at each source-detector pairing, time-domain approaches provide fluorescence intensity throughout the whole temporal response to the pulsed-laser excitation, adding a whole new dimension to the dataset. This paper introduces the instrumentation required to collect time-domain data, dealing with complications and nuances of system and data calibration, as well as the major current applications of time-domain diffuse fluorescence imaging.