Recent Advances in Functional Chelators for PET and SPECT Imaging Probes

Area of Science:

• Molecular imaging
• Radiochemistry
• Biomedical engineering

Background:

• Positron Emission Tomography (PET) and Single-Photon Emission Computed Tomography (SPECT) are key molecular imaging techniques.
• Radiometal-based probes are increasingly important, utilizing chelators to bind radionuclides to targeting molecules.
• Chelator choice significantly impacts probe stability, labeling efficiency, and in vivo performance.

Purpose of the Study:

• To review recent advancements in chelator design for radiometal-based molecular imaging.
• To explore how chelator innovations influence PET and SPECT probe development.
• To discuss the impact of chelators on targeted radionuclide therapy and theranostics.

Main Methods:

• Review of recent literature on chelator design for PET and SPECT imaging.
• Analysis of acyclic and macrocyclic chelator properties and applications.
• Discussion of innovations like [18F]AlF-NOTA chemistry and optimized DFO derivatives.

Main Results:

• Acyclic chelators offer rapid labeling but may lack in vivo stability.
• Macrocyclic chelators provide enhanced kinetic inertness but often require harsher labeling conditions.
• Innovations have led to improved chelators for specific radionuclides (e.g., 89Zr, Cu) and applications (e.g., FAPI, theranostics).

Conclusions:

• Chelator design is critical for optimizing radiometal-based probes for molecular imaging and therapy.
• Ongoing research focuses on user-friendly, kit-based chelators for broader radionuclide applicability.
• Advancements in chelators are expanding the scope of molecular imaging and targeted radionuclide therapy.