Fully automated synthesis system of 3′-deoxy-3′-[18F]fluorothymidine

We developed a new fully automated method for the synthesis of 3'-deoxy-3'-[F-18]fluorothymidine ([F-18]FLT), by modifying a commercial FDG synthesizer and its disposable fluid pathway. Optimal labeling condition was that 40 mg of precursor in acetonitrile (2 mL) was heated at 150 degreesC for 100 sec, followed by heating at 85 degreesC for 450 sec and hydrolysis with I N HCI at 105degreesC for 300 sec. Using 3.7 GBq of [F-18]F- as starting activity, [F-18]FLT was obtained with a yield of 50.5 +/- 5.2% (n = 28, decay corrected) within 60.0 +/- 5.4 min including HPLC purification. With 37.0 GBq, we obtained 48.7 +/- 5.6% (n= 10). The [F-18]FLT showed the good stability for 6 It. This new automated synthesis procedure combines high and reproducible yields with the benefits of a disposable cassette system. (C) 2004 Elsevier Inc. All rights reserved.