On Site Production of [18F]-PSMA1007 Using Different [18F]-fluoride Activities. Practical, Technical and Economical Impact.

Abstract BackgroundProstate-Specific Membrane Antigen is overexpressed in prostate cancer and it is considered a good target for staging of primary and recurrences as well as for radioligand therapy. Different PSMA-analogues have been investigated, labeled with [68Ga], showing excellent imaging properties; although, only small amounts can be produced for single synthesis. Recently, a fluorinated PSMA-inhibitor, [18F]-PSMA-1007, has been introduced, ensuring large-scale productions. In this study, the radiosynthesis of [18F]-PSMA-1007 using low (A), medium (B) and high (C) starting activities of [18F]-Fluoride, has been fully tested. The following parameters radiochemical yield, radiochemical purity and stability of [18F]-PSMA-1007 have been measured in 65, consecutive batches to verify the effects of the three different conditions. In addition, the analysis of the costs for the production has been performed. ResultsThe radiochemical yield percentage for low and medium range of activities of [18F]-Fluoride was 52%, while for the high range it decreases to 40%. The radiochemical purity was 99% in all three tested starting activities. [18F]-PSMA-1007 did not show radiolysis up to 8 hours after the end of synthesis, confirming that the radiopharmaceutical is stable an suitable for PET studies in humans. Furthermore, stability studies performed in fetal bovine serum demonstrated radiochemical stability at 37°C for 120’. ConclusionsA starting activity of [18F]-Fluoride of 90 GBq (range B) enables a final amount of [18F]-PSMA-1007 of about 50 GBq, which is powerful for different choices: to perform up to 25 PET/CT scans in a referral institution for prostate cancer, and/or to supply the eventual peripheral PET centers.