FN1 and neoplasm: Another scaffold protein, [64Cu]Cu-FnEI3.4.3′, which is based on a 10 kDa fibronectin binding domain, provided good tumor visualization using PET and superior tumor-to-blood contrast to the 64Cu-labeled affibody just 1 h pi [149,150] and might be another possible alternative for imaging of HER1 expression.