68Ga macht seit einiger Zeit eine steile Karriere in Radiopharmazie und klinischer PET und hat für einige Krankheitsbilder das Patientenmanagement erheblich beeinflusst. Wird dieser Boom anhalten?
The nuclide properties of Gallium-68 are less favorable than those of 18F. However, in most instances, the labeling procedures of 68Ga are more robust and rapid as compared to 18F chemistry. Like 99 mTc, 68Ga is obtained from radionuclide generators. Hence, 68Ga-radiopharmaceuticals can be synthesized independently from an on-site cyclotron. 68Ge / 68Ga-generators are considered pharmaceuticals and require an approval by the BfArM in order to be used for patient care. Although currently, 68Ga tracers are mostly synthesized using robotics, kit synthesis are feasible if approved generators are used. Some kits have been approved recently, and more will follow. Using a cyclotron, much larger amounts of 18F-tracers can be produced in a single batch as compared to 68Ga-tracers, which is why a single dose of a 18F radiopharmaceutical comes at a much lower price. Hence, for blockbuster applications, 68Ga-radiopharmaceuticals will ultimately be replaced by their 18F analogs. This, however, only applies as long as 68Ga cannot be produced in similar amounts and efficiency using cyclotrons. Somatostatin receptor PET with 68Ga radiopharmaceuticals represents a stronghold in management of neuroendocrine tumors, which will be further strengthened in light of the approval of respective 68Ga-labeling kits for SSTR ligands. 68Ga-PSMA-PET diagnostics of prostate carcinoma is a major breakthrough for dissemination and wide application of 68Ga radiopharmaceuticals. It is anticipated that several 68Ga-PSMA-tracers will obtain a marketing authorization soon. Further 68Ga-tracers are currently being evaluated and show promising results, but their clinical value will have to be proven in prospective studies.
Schlüsselwörter
Gallium-68 - Radionuklidgeneratoren - Positronenemissionstomografie - Neuroendokrine - Tumoren - Prostatakarzinom