The 18F- and 68Ga-radiolabeled camelid single-domain antibody fragments [18F]FB-anti-MMR-sdAb and [68Ga]Ga-NOTA-anti-MMR-sdAb are able to detect CD206-positive tumor-associated macrophages, and the latter has recently entered in clinical studies [22–24]. The gene discussed is MRC1; the disease is neoplasm.