Lifetime characteristics of commercial NIR fluorophores. Emission wavelengths are taken from product literature. Mean lifetime ± the standard deviation are derived from monoexponential fit of images taken at time points from 1 min to 24 h following fluorophore injection with the mouse supine or prone, depending on the organs of interest. Only pixels with peak intensity >10% of the maximum intensity were considered in the fit (to avoid low-intensity noisy pixels). The standard deviation for all pixels was ∼2 to 3× the values listed here. τ±(ps) for Kodak X-Sight 761 shows lifetime shortening in the liver over 14 h and for Atto 740 lifetimes in the kidneys and bladder, respectively. Alexa 750 is antibody conjugated.