FAPI Uptake in Gallbladder Is It Normal Biodistribution?

Abstract Radiolabeled fibroblast activation protein inhibitors (FAPIs) have been extensively used in different types of cancers, although not yet FDA approved. Normal patterns of FAPI biodistribution have been investigated, and it is known that FAPI is expressed in nonmalignant pathophysiological lesions, characterized by tissue remodeling such as atherosclerosis, arthritis, and scar/fibrotic tissues. In this interesting image, we are presenting the accumulation of 68 Ga-FAPI in the gallbladder. This finding could be related to a normal distribution of the radiotracer as a physiologic finding. This is a potentially important finding as FAPI may be used as theragnostic agent in the future.