Option for increased yield of the 18F-FDG synthesis process

Abstract

Introduction: 2-[18F]fluoro-2-deoxy-D-glucose ([18F]FDG) is the most commonly used radiopharmaceutical in clinical molecular imaging. The process of FDG synthesis is under constant development to optimise and increase yields. Aim: Review of [18F]FDG radiopharmaceutical production with ABT cyclotron and chemistry module. Materials and Methods: The 18F radionuclide we work with, is the product of a 18O (p, n)18F nuclear reaction by irradiation (30-45 min) of enriched [18O]H2O. Our process of choice for FDG production is nucleophilic fluorination using mannose triflate as precursor and Kryptofix because of the proven high yields and short reaction time. Synthesis itself is achieved by nucleophilic substitution and acid hydrolysis with passive cooling (air at room temperature) or an active one (CO2 gas).The quality of each dose is checked by an automatic QC system and 4 manual QC tests. The QCM automatically performs pH determination, residual solvents (acetonitrile and ethanol), radiochemical identity/purity, Kryptofix 2.2.2. determination, and filter integrity test. Results: We have observed a huge difference in dose activity when using the two different types of cooling. Between 10 and 16 mCi with passive cooling and 14 and 26 mCi when using active СО2 cooling. The heightened dose activity is a result of cutting the overall synthesis time. Conclusions: Active СО2 gas cooling leeds to shorter synthesis times and higher yields without affecting the quality of the end product [18F]FDG.