A radiolabeled annexin comprising at least 2 up to 20 histidine residues at its N-terminus is disclosed. At least two of said histidine residues are adjacent or separated by no more than one other amino acid. The radiolabeled annexin is a stable complex with a radionuclide such as technetium 99m. The radiolabeled annexin can be used in a method of imaging cell death in a nucleated cell within a region of a mammalian subject in vivo.
