MRC1 and temporal arteritis: New candidate radiotracers targeting macrophage subsets in GCA include [18F]fluoro-PEG-folate (targeting FRβ), [68Ga]NOTA-anti-MMR-sdAb (targeting CD206), [68Ga]-labeled anti-CD163-antibody (targeting CD63), and [68Ga]DOTA-TCTP- 1 (targeting MMP-2/9) (Eichendorff et al., 2015; Stellingwerff et al., 2015; Kiugel et al., 2018; Moisio et al., 2020; Verweij et al., 2020).