Automated [18F]PSMA-1007 production by a single use cassette-type synthesizer for clinical examination

Background[F-18]PSMA-1007, a positron emission tomography (PET) tracer, specifically targets prostate-specific membrane antigen (PSMA), which is highly expressed in prostate cancer. PSMA-PET is effective especially for regional detection of biochemical recurrence, which significantly affects patient management. Herein, we established and optimized a one-step radiolabeling protocol to separate and purify [F-18]PSMA-1007 with a CFN-MPS200 synthesizer for clinical application.ResultsA dedicated single use cassette and synthesis program for [F-18]PSMA-1007 was generated using a single-step method for direct precursor radiolabeling. In the cassette, three tube types (fluoro-elastomer, PharMed (R) BPT, silicone) and two different precursor salts (trifluoroacetic acid or acetic acid) were compared for optimization. Furthermore, three-lot tests were performed under optimized conditions for quality confirmation. Activity yields and mean radiochemical purity of [F-18]PSMA-1007 were>5000MBq and 95%, respectively, at the end of synthesis, and the decay-corrected mean radiochemical yield from all three cassettes was approximately 40% using a trifluoroacetic acid salt precursor. Fluoro-elastomer tubings significantly increased the amount of non-radioactive PSMA-1007 (8.53.1 mu g/mL) compared to those with other tubings (0.3 mu g/mL). This reduced the molar activity of [F-18]PSMA-1007 synthesized in the cassette assembled by fluoro-elastomer tubings (46GBq/mu mol) compared to that with PharMed (R) BPT and silicone tubings (1184 and 1411GBq/mu mol, respectively). Residual tetrabutylammonium, acetonitrile, and dimethyl sulfoxide levels were< 2.6 mu g/mL, <8ppm, and< 11ppm, respectively, and ethanol content was 8.0-8.1% in all three cassettes and two different salts. Higher activity yields, radiochemical purities, and decay-corrected radiochemical yields were obtained using an acetic acid salt precursor rather than a trifluoroacetic acid salt precursor (7906 +/- 1216MBq, 97%+/- 0%, and 56%+/- 4%). In the three-lot tests under conditions optimized with silicone cassettes and acetic acid salt precursor, all quality items passed the specifications required for human use.Conclusions We successfully automated the production of [F-18]PSMA-1007 for clinical use and optimized synthesis procedures with a CFN-MPS200 synthesizer using a silicone cassette and acetic acid salt precursor. Cassette availability will facilitate a wide spread use of [F-18]PSMA-1007-PET, leading to an effective prostate cancer management.