Authors: Muzzioli R1, Paolillo V2, Zacharias Millward N3, Gammon ST1, Pisaneschi F1, Piwnica-Worms D1 1Department of Cancer System Imaging, 2Center for Advanced Biomedical Imaging, 3Department of Urology; The University of Texas MD Anderson Cancer Center, Houston,77034, TX, USA Background Three PET tracers, among those synthesized at MD Anderson Cancer Center, were selected for a comparative analysis of radiolabeling efficiency using two different approaches: a classic “reactor” automated system or a microfluidic system. The tracers selected were: [18F]fluoroazomycin arabinoside ([18F]FAZA), 4-[18F]fluoronaphthol ([18F]4FN) and -4-[18F]fluoroglutamine ([18F]FGln). Aims The study aims to compare the radiolabeling conditions of three different PET tracers using an automated synthesis module (GE-Tracerlab-FX for [18F]FAZA and [18F]4FN, and GE-Tracerlab-FX2N for [18F]FGln) and a microfluidic system (Avion-NanoTek). The goal is to have a work-flow that allows screening in microfluidics and scale-up on a classic reactor. Methods The synthesis of [18F]4FN uses a copper-mediated radiofluorination/deprotection of an aryl boronic esters precursor[1]. The radiolabeling reaction for the synthesis of [18F]FGln[2] and [18F]FAZA[3] is based on a nucleophilic substitution (SN2), starting from a precursor that bears a tosylate moiety as leaving group. Results and Conclusion All the PET tracers were synthetized on GE Tracerlab. [18F]4FN was obtained in 6.8±2.5% (n=22) activity yield, [18F]FGln in 8.5±2.9 % (n=7) radioactivity yield and [18F]FAZA in a 28.1±3.8 % (n=37) activity yield, with> 99% radiochemical purity and high molar activity. Radiolabeling of the tracers on the NanoTek is underway. References1. Tredwell, M., et al., A General Copper-Mediated Nucleophilic 18F Fluorination of Arenes. Angewandte Chem. Int. Edit., 2014. 53(30): p. 7751-7755.2. Zhang, X., et al., Automated synthesis of [(18)F](2S,4R)-4-fluoroglutamine on a GE TRACERlab FX-N Pro module. Appl Radiat Isot, 2016. 112: p. 110-4.3. Reischl, G., et al., Preparation of the hypoxia imaging PET tracer [18F]FAZA: reaction parameters and automation. Appl. Radiat. Isot., 2005. 62(6): p. 897-901.