CHAPTER 4: The Role of Fundamental Coordination Chemistry in the Development of Radioimaging Agents

Molecular imaging is an expansive and rapidly growing field. Metallic elements such as ⁶⁷Ga, ⁶⁸Ga, ^99mTc, ¹¹¹In, ⁶⁴Cu, ⁸⁶Y, ⁸⁹Zr are accessible radioisotopes that can be incorporated into diagnostic imaging agents for single photon emission computed tomography (SPECT), or positron emission tomography (PET). The role of the coordination chemistry of the metals is crucial in designing appropriate ligands for the development of new and more effective probes. This article highlights the fundamental coordination chemistries of radiometals that are currently of interest for radio-pharmaceutical design. This subtle interplay of coordination chemistry, multi-functional chelate design, and radiopharmaceutical development is illustrated through four specific examples from our own work: (1) single amino acid chelates (SAACs) for the design of labeled radioconjugates, (2) vitamin B₁₂-based imaging agents, (3) novel PET agents based on ⁸⁹Zr and (4) developments in PET imaging based on the coordination chemistries of copper and gallium.