Abstract: Objective To study a new fully automated method for the synthesis of [¹⁸F]fluoromisonidazole(¹⁸F-FMISO) by a home made FDG synthesizer.Methods The optimal labeling conditions for the automated synthesis of ¹⁸F-FMISO was 4～6 mg precursor in 1 mL acetonitrile heated at 110 ℃ for 300 s at pressurized vessel,and hydrolyzed with 1 mol/L HCl at 120 ℃ for 180 s with modified FDG synthesizer.The biodistribution and PET scan were performed in normal and lung tumor bearing mice.Results The yield of ¹⁸F-FMISO was 67% with modified FDG module.It took 25 min.The radiochemical purity was over 99%.The stabilization of ¹⁸F-FMISO was good in vitro.The PET scan showed that the tumor took up ¹⁸F-FMISO.The ratio of tumor to muscle was 2.99 at 120 min.The liver,kidney and intestines took up ¹⁸F-MISO abundantly.Conclusion The modified FDG module can be used for synthesis of high yield ¹⁸F-FMISO.It could be used in clinical practice as a potential radiopharmaceutical for the non-invasive detection of hypoxia in thorax and neck tumors.

Key words: ¹⁸F-FMISO, automated synthesis, tumor hypoxia, PET imaging