FAP and neoplasm: With selective targeting of FAP, and better imaging characteristics of FAPI-PET, a more accurate delineation of additional areas of interest (i.e., the tumor microenvironment) may be of clinical benefit, such as in head and neck cancer with 68Ga-FAPI, where differentiation between residual/recurrent disease and post-chemoradiation fibrosis may be a diagnostic challenge for 18F-FDG (71).