Figure 2From: Multimodality imaging using SPECT/CT and MRI and ligand functionalized 99mTc-labeled magnetic microbubbles Chemical structures of the ligands DTPA and NOTA. The polyamines with the chelating ligand DTPA or NOTA react with isothiocyanates at pH 8 to form a stable isothiourea bond in the molecule containing NOTA or DTPA.Back to article page