Gallium: New developments and applications in radiopharmaceutics

The chemistry of gallium has played a key role in nuclear medicine for half a century. Its applications have centered around two principal radionuclides, gallium-67 and gallium-68. Developments in the chemistry of gallium and its radionuclides in the last few years have led to advances in simple, convenient preparation of biomolecular conjugate-based radionuclides using novel chelating agents, including clinical applications; use of radionuclide imaging to elucidate the pharmacokinetics of gallium-based anticancer drugs; exploiting the biological chemistry of gallium as a basis for radionuclide imaging of cancer and microbial infection; potential use of gallium-67 as an Auger electron-emitting therapeutic radionuclide; and exploitation of the affinity of gallium for fluoride to develop simple methods for labeling biomolecules with the positron-emitting radionuclide fluorine-18. This review provides an update on each of these areas of gallium chemistry in the context of its interface with nuclear medicine, illustrated by recent collaborative contributions of the authors, who form a group of UK academic groups sharing common interests.