Extended Data Fig. 1: Measurements of endogenous tissue autofluorescence in the NIR.
Photograph (a), fluorescence intensity (b), and FLT map (c) of a freshly resected metastatic colorectal cancer (mCRC) specimen without ICG injection. T, Tumor; N, Normal liver parenchyma. White dashed lines in a-c indicate the clinically defined tumor boundary. In the absence of ICG, the FLT of tumor autofluorescence (AF) was 0.22 ± 0.01 ns. Histology (d), confocal fluorescence intensity (e), and FLIM (f) images of a 10 µm OCT embedded tissue section obtained from a region of interest (a, yellow dotted outline). The mean tumor AF FLT measured via confocal FLIM was 0.37 ± 0.05 ns. g, Representative wide-field time domain (TD) fluorescence decay curves obtained from an mCRC specimen without ICG (green) and a specimen with ICG (red). The peak of the TD data (represented by the horizontal dashed lines) is representative of the fluorescence intensity in each mCRC tumor. Comparing the AF with tumor ICG intensity, we observed a nearly 20-times stronger signal in the ICG-injected specimen. h, Normalized plots of the TD data from (g), showing a significantly longer FLT of tumor-ICG (red = 0.61 ns) compared to the AF FLT (green = 0.22 ns), thus confirming that the tumor FLT observed with pre-surgery ICG administration arises from the tumor uptake of ICG.
