Fully automated production of the fibroblast activation protein radiotracer [¹⁸ F]FAPI-74

We report herein an efficient and fully automated protocol for the radiosynthesis of [¹⁸ F]FAPI-74, a new positron emission tomography (PET) radiopharmaceutical for in vivo detection of the fibroblast activation protein. [¹⁸ F]FAPI-74 was synthesized via a rapid [¹⁸ F]aluminum fluoride coordination reaction, which was first developed on the flexible GE TRACERLab FX2N (FXN) platform and later translated to the cassette-based module Trasis AllInOne (AIO). The results obtained with both modules were comparable in terms of yield and reproducibility. Automation of [¹⁸ F]FAPI-74 radiosynthesis on the FXN was carried out in 35 min with a radiochemical yield (RCY) of 18.5 ± 2.5% (n = 5, relative to starting [¹⁸ F]fluoride). Method transfer to the AIO platform following minor optimizations allowed for the production of [¹⁸ F]FAPI-74 in an isolated RCY of 20 ± 2.5% [n = 3] with an overall synthesis time of 40 min. The radiochemical purity was greater than 95% for [¹⁸ F]FAPI-74, obtained from both modules. Overall, the protocol reliably provides a sterile and pyrogen-free good manufacturing practice (GMP) compliant product of [¹⁸ F]FAPI-74 suitable for clinical PET imaging.