CCR2 and idiopathic pulmonary fibrosis: A Cu-64-labeled peptide-based agent recognized the extracellular loop one (ECL1) of CCR2, enabling non-invasive localization and quantification of the CCR2+ inflammatory cell burden and specific monitoring of CCR2 activity associated with fibrosis using PET imaging, as validated in both preclinical animal models and clinical investigations of IPF [34,117].