Compound [64Cu]Cu-3 is an analogue of [64Cu]Cu-1 bearinga methyl sulfonyl instead of the nitrile group at the pyridine ring.Remarkably, this small structural modification seemed to influencethe tumor uptake because [64Cu]Cu-3 showeda clear uptake in the PD-L1-overexpressing tumor with good contrastover the mock tumor. The gene discussed is CD274; the disease is neoplasm.