Automated SPE-based synthesis of 16α-[18F]fluoroestradiol without HPLC purification step

[18F]fluoroestradiol ([18F]FES) is well-established PET radiotracer for diagnosing and monitoring treatment of estrogen-positive breast cancer. The radiotracer is produced via one-pot two steps synthesis using cyclic sulfate precursor and is usually purified by semi-preparative HPLC. Here we suggested simple SPE purification procedure using OASIS WAX 3cc and Sep-Pak QMA light cartridges that afforded [18F]FES in typically 15% RCY (corrected for decay) within 45 min formulated in 5% EtOH/saline. All purity parameters were well within specifications recommended in the Investigator's Brochure for [18F]Fluoroestradiol.