Improved automated synthesis of [18F]fluoroethylcholine as a radiotracer for cancer imaging

[18F]Fluoroethylcholine has been recently introduced as a promising 18F-labelled analogue of [11C]choline which had been previously described as a tracer for metabolic cancer imaging with positron emission tomography (PET). Due to the practical advantages of using the longer-lived radioisotope 18F (t1/2 = 110 min), offering the opportunity of a more widespread clinical application, we established a reliable, fully automated synthesis for its production using a modified, commercially available module. [18F]Fluoroethylcholine was prepared from N,N-dimethylaminoethanol by iodide catalyzed alkylation with 1-[18F]fluoro-2-tosylethane as alkylating agent, resulting in a total radiochemical yield of 30 ± 6% after a synthesis time of 50 min. The specific activity of [18F]fluoroethylcholine was >55 GBq/μmol and the radiochemical purity 95–99%.

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