Designing and implementing various radionuclide production methods guarantees a sustainable supply, which is important for medical use. The use of medical cyclotrons for radiometal production can increase the availability of gallium-68 (68Ga) radiopharmaceuticals. Although generators have greatly influenced the demand for 68Ga radiopharmaceuticals, the use of medical cyclotrons is currently being explored. The resulting 68Ga production is several times higher than obtained from a generator. Moreover, the use of solid targets yields end of purification and end of synthesis (EOS) of up to 194 GBq and 72 GBq, respectively. Furthermore, experiments employing liquid targets have provided promising results, with an EOS of 3 GBq for [68Ga]Ga-PSMA-11. However, some processes can be further optimized, specifically purification, to achieve high 68Ga recovery and apparent molar activity. In the future, 68Ga will probably remain one of the most in-demand radionuclides; however, careful consideration is needed regarding how to reduce the production costs. Thus, this review aimed to discuss the production of 68Ga radiopharmaceuticals using Advanced Cyclotron Systems, Inc. (ACSI, Richmond, BC, Canada) Richmond, Canada and GE Healthcare, Wisconsin, USA cyclotrons, its related factors, and regulatory concerns.
Objective: To compare the radiochemical synthesis, stability, and clinical performance of cyclotron-produced [ 18 F]PSMA-1007 and [⁶⁸Ga]PSMA-11 for prostate-specific membrane antigen (PSMA)-targeted PET/computed tomography (CT) imaging in prostate cancer. Methods: Six production runs each of [¹⁸F]PSMA-1007 and [⁶⁸Ga]PSMA-11 were conducted using a cyclotron-based system. Radiochemical yield, radiochemical purity, and product stability were evaluated according to European Pharmacopeia standards. Thirty-five patients with prostate cancer underwent dual-tracer PET/CT imaging within 30 days. Images were assessed for lesion detectability, biodistribution, and pitfalls by three independent nuclear medicine physicians using semiquantitative metrics. Results: [¹⁸F]PSMA-1007 demonstrated substantially higher end-of-synthesis activity (mean: 75.68 GBq) compared with [⁶⁸Ga]PSMA-11 (mean: 1.76 GBq), with both achieving high RCP (>98%) and comparable synthesis durations. Stability testing confirmed [¹⁸F]PSMA-1007 remained radiochemically stable for up to 9 h. Clinically, both tracers showed high concordance in PSMA-avid lesion detection. [¹⁸F]PSMA-1007 exhibited superior contrast in prostate and skeletal lesions because of minimal urinary excretion but also revealed higher rates of benign uptake in ganglia and nonspecific bone sites, leading to increased discordant findings (104 vs. 47 lesions). Conclusion: [¹⁸F]PSMA-1007 provides significant advantages in production scalability and lesion detectability, particularly in skeletal and pelvic regions; however, its higher rate of benign uptake necessitates careful interpretation to avoid false positives. While both tracers are clinically effective, tracer selection should be guided by logistical feasibility, clinical context, and interpretive considerations.
8 November 2021 in Journal of Radioanalytical and Nuclear Chemistry