⁶⁴Cu-labeled agents for molecular imaging of cancer

The development of multi-functional complexing agents for radiometal nuclides with a view of nuclear medical application represents a field of research that is intensively dealt with and has rapidly been developing. In this context, ligands that form highly stable metal complexes and additionally possess several different functional groups are of particular interest. This enables the simultaneous introduction of targeting, solubilizing and, for example, fluorescent units into the relevant metal complexes. This allows, on the one hand, adjusting defined features of solubility and of selective binding properties with a view of in vivo application with controllable targeting. There is the possibility of dual labeling, on the other, for the simultaneous application of different imaging techniques on the basis of radioactive labeling for SPECT (single-photon emission computed tomography) / PET (positron emission tomography) and of a fluorescent unit for optical imaging. In that way, tumors can be localized by means of PET, for instance, and, during subsequent surgery, the fluorescent label of the compound applied will permit to clearly differentiate between healthy and malign tissue (fluorescence guided surgery). Besides, the application of fluorescent compounds allows investigating cellular processes and exactly localizing these compounds in cell compartments. Here, we discuss specific examples of multi-functional ligand systems and nanomaterials, enabling simultaneous imaging of cancer using ⁶⁴Cu PET and fluorescence imaging.