Comparison of Two Cameras based on Single Photon Avalanche Diodes (SPADs) for Fluorescence Lifetime Imaging Application with Picosecond Resolution

We report on a comparative study of two time-resolved cameras based on digital Single Photon Avalanche Diodes (SPADs) for Fluorescen ce Lifetime Imaging applications. In contrast to standard imagers such as cameras, SPAD imagers provide intensity as well as direct access to the fluorescence decay temporal profile, from which lifetime contrast can be extracted. Intensity images provide physicians with anatomical information to localize cancerous tissue; lifetime maps on the other hand provide metabolic information on tissues and can help detect the presence and location of metastatic cells [1,2,3]. With a timing resolution better than 100ps in a compact setup, the SPAD camera represents an innovative solution to explore subnanosecond fluorescence mechanisms.