gallium68

Gallium-68 (Ga-68) is a positron-emitting radionuclide used in PET imaging. It has a half-life of about 68 minutes and decays by positron emission to stable zinc-68. The emitted positrons annihilate with electrons, producing pairs of 511 keV photons that are detected in PET scans. The short half-life enables rapid imaging with reduced radiation exposure to patients.

Production and availability: Ga-68 is commonly produced from a germanium-68/gallium-68 generator. Germanium-68, with a half-life of about 271 days, serves as the parent radionuclide in the generator, which is eluted to yield Ga-68 as GaCl3. The material is then used to radiolabel various compounds for clinical imaging. Generator-based production supports decentralized use in hospitals and radiopharmacies.

Chemistry and radiopharmaceuticals: Ga3+ forms stable complexes with chelators such as DOTA and NOTA, enabling labeling of peptides and small molecules that target specific receptors. Widely used Ga-68 radiopharmaceuticals include Ga-68 DOTATATE, Ga-68 DOTATOC, and Ga-68 DOTANOC for somatostatin receptor imaging, and Ga-68 PSMA-11 for prostate cancer imaging. Ongoing research explores additional targets and labeling strategies.

Applications: Ga-68 labeled radiopharmaceuticals are primarily employed in diagnostic PET imaging to detect and stage cancers, guide therapy decisions, and monitor treatment response. The generator-based production allows on-site synthesis at many medical centers, improving accessibility for patients.

Safety and regulation: The short half-life contributes to a relatively favorable radiation profile for diagnostic procedures. Handling and use require appropriate radiopharmacy facilities, shielding, and regulatory approvals for the specific radiopharmaceuticals employed.