18F fluoroethylations: different strategies for the rapid translation of 11C-methylated radiotracers

• Published in: Nuclear medicine and biology 2007-11, Vol.34 (8), p.1019-1028
• Main Authors: Wadsak, Wolfgang, Mien, Leonhard-Key, Ettlinger, Dagmar E., Eidherr, Harald, Haeusler, Daniela, Sindelar, Karoline-Maria, Keppler, Bernhard K., Dudczak, Robert, Kletter, Kurt, Mitterhauser, Markus
• Format: Article
• Language: English
• Subjects: Carbon Radioisotopes - chemistry; FETO; Fluorine Radioisotopes - chemistry; Fluorine-18; Fluoroethylation; Isotope Labeling - instrumentation; Isotope Labeling - methods; Methylation; PET; Radiopharmaceuticals - chemical synthesis
• ISSN: 0969-8051; 1872-9614
• DOI: 10.1016/j.nucmedbio.2007.06.012

The translation of 11C-labeled compounds into their respective 18F-labeled derivatives is an important tool in the rapid development of positron emission tomography (PET) tracers. Thus, our aim was the development of a general method for the preparation of 18F-fluoroethylated compounds that (a) is applicable to a variety of precursors, (b) can be performed in a fully automated commercially available synthesizer and (c) enables this rapid translation of 11C-methylated tracers into their 18F-fluoroethylated analogs sharing the same precursor molecules. Ten methods for the preparation and purification of different 18F-fluoroethylating agents were compared. Subsequently, five 18F-labeled PET tracers were synthesized under fully automated conditions. Radiochemical yields ranged from 34.4% to 60.8%, and time consumption ranged from 20 to 55 min for all methods. Use of 1-bromo-2-[ 18F]fluoroethane and distillation evinced as the method of choice. We were able to develop a general method for the preparation of a variety of 18F-fluoroethylated molecules. The provided tool is solely based on commercially available resources and has the potential to simplify and accelerate innovative PET tracer development in the future.