Optimization was conducted to improve the RCY using the newly-established automated protocol: increasing the temperature for the labelling reaction to 110 °C improved the RCY to 15.6 % whilst reduction of the deprotection temperature was tolerated and gave an improved RCP of 96 % (Table , Entry 3). We found that an increase in volume of the reaction mixture was key to improving the RCY. Initially, the amount of precursor was doubled in order to maintain precursor concentration ( ). Finally, further adjustments were made to the automation to reduce the synthesis time. The water wash was reduced from 60 mL to 28 mL, whilst increasing the elution and washing speed from 7.5 mL/min to 17.5 mL/min. Both of these adjustments reduced the synthesis time from 83 minutes to 65 minutes. These changes also resulted in an improved RCY of 38.4 ± 2.6 % (Table , Entry 7), corresponding to a non-decay corrected RCY of 25.5 % and the production of 382.5 MBq of [ 18 F]FSPG at end of synthesis (EOS) from 1.5 GBq starting activity. These conditions were chosen as optimal, balancing RCY, total synthesis time, and the relative expense of the precursor.