Fully-automated synthesis of 16β-18F-fluoro-5α-dihydrotestosterone (FDHT) on the ELIXYS radiosynthesizer

•Manual radiosynthesis of 18F-FDHT was adapted for full automation on the ELIXYS radiosynthesizer.•Reduction with LiAlH4 was performed at room temperature to avoid cryogenic conditions.•Formulated product passed all clinical QC tests and is suitable for clinical production.•Decay-corrected radiochemical yield was 29±5% (n=7) with a synthesis time of 90 min.•Specific activity was 4.6 Ci/µmol (170 GBq/µmol) at the end of formulation.

Noninvasive in vivo imaging of androgen receptor (AR) levels with positron emission tomography (PET) is becoming the primary tool in prostate cancer detection and staging. Of the potential 18F-labeled PET tracers, 18F-FDHT has clinically shown to be of highest diagnostic value. We demonstrate the first automated synthesis of 18F-FDHT by adapting the conventional manual synthesis onto the fully-automated ELIXYS radiosynthesizer. Clinically-relevant amounts of 18F-FDHT were synthesized on ELIXYS in 90 min with decay-corrected radiochemical yield of 29±5% (n=7). The specific activity was 4.6 Ci/µmol (170 GBq/µmol) at end of formulation with a starting activity of 1.0 Ci (37 GBq). The formulated 18F-FDHT yielded sufficient activity for multiple patient doses and passed all quality control tests required for routine clinical use.