To this end, we imaged ECP-treated lung recipients using a PET-purposed radiotracer, 64Cu-DOTA-ECL1i, which specifically recognizes the extracellular loop number 1 of CCR2 and is under current clinical evaluation for noninvasive diagnosis of idiopathic pulmonary fibrosis (48). Here, CCR2 is linked to idiopathic pulmonary fibrosis.