DOTAGA-anhydride is a DOTA-based metal chelator that can bind to radionuclides and is used to prepare radionuclide drug conjugates (RDCs). DOTAGA-anhydride has been successfully used for labeling antibodies (e.g., Trastuzumab (HY-P9907)). DOTAGA-anhydride can be used for the synthesis of a bimodal tag for Single-photon emission computed tomography (SPECT) or PET/optical imaging[1].