Optimization and Stabilization of Automated Synthesis Systems for Reduced 68Ga-PSMA-11 Synthesis Time

Abstract

Gallium-68-prostate-specific membrane antigen-11 (68Ga-PSMA-11) is a positron emission tomography radiopharmaceutical that labels a Glu-urea-Lys-based ligand with 68Ga, binding specifically to the PSMA. It is used widely for imaging recurrent prostate cancer and metastases. On the other hand, the preparation and quality control testing of 68Ga-PSMA-11 in medical institutions takes over 60 minutes, limiting the daily capacity of 68Ge/68Ga generators. While the generator provides 1,110 MBq (30 mCi) nominally, its activity decreases over time, and the labeling yield declines irregularly. Consequently, additional preparations are needed, increasing radiation exposure for medical technicians, prolonging patient wait times, and necessitating production schedule adjustments. This study aimed to reduce the 68Ga-PSMA-11 preparation time and optimize the automated synthesis system. By shortening the reaction time between 68Ga and the PSMA-11 precursor and adjusting the number of purification steps, a faster and more cost-effective method was tested while maintaining quality. The final synthesis time was reduced from 30 to 20 minutes, meeting the standards for the HEPES content, residual solvent EtOH content, and radiochemical purity. This optimized procedure minimizes radiation exposure for medical technicians, reduces patient wait times, and maintains consistent production schedules, making it suitable for clinical application.

Keywords

• automated synthesis
• 68ga-psma-11
• hepes
• quality control
• synthesis optimization