In order to increase the blood circulation time and potentially increase tumor uptake of the tracer, Kwon et al. linked the Fab of the trastuzumab to that of the EGF through a PEG24 linker, conjugated the resulting construct to NOTA, and radiolabeled with 64Cu to obtain 64Cu-NOTA-Fab-PEG24-EGF. Here, EGF is linked to neoplasm.