Design and validation of an intraoperative autofluorescence lifetime imaging device

摘要

As we know, fluorescence lifetime imaging has demonstrated the ability to accurately detect materials and tissueconstituents. Current fluorescence lifetime systems rely on accurate temporal sampling to capture the tails of thedecaying emission. These data are often fit to an exponential decay model. Although these methodologies arepowerful tools but they are often implemented as point measurement systems and require significant postprocessing tocompute decay times or coefficients. In some applications these factors can hinder clinical translation. Based on theseobservations, our group has developed algorithms and built simple, fast, and wide field imaging system. This methoduses a gated charge-coupled device (CCD) and a liquid light cable guided LED to compare the decay-time imageintensity vs excited state image intensity, thus generating a spatially resolved maps of relative differences in autofluorescencedecay of tissue constituents. This approach ensures very fast updating speed (< 2 sec per frame), big field ofview (20 mm × 20 mm), excellent depth of field (up to 6 mm) for surface curvature of interested target at reasonableworking distance (~50 mm). This innovative imaging system has a temporal resolution of 0.16 nanosecond, spatialresolution of 70 μm and has proved the capability to differentiate visibly similar tissue types, which has been validatedwith both fluorescent dyes and ex vivo human tissue samples in comparison to commercially available FLIMmicroscope. This work establishes a foundation to confirm the utility of our upgraded DOCI system for intraoperativetissue differentiating/imaging. Validation with a larger number of samples is currently ongoing.