Automated radiosynthesis of [18F]SPA-RQ for imaging human brain NK1 receptors with PET

Authors

  • Frederick T. Chin,

    Corresponding author
    1. PET Radiopharmaceutical Sciences Section, Molecular Imaging Branch, National Institute of Mental Health, National Institutes of Health, Building 10, Room B3 C346, 10 Center Drive, Bethesda, MD 20892-1003, USA
    • Molecular Imaging Program, Stanford University School of Medicine, Lucas MRS Center, MC 5484, Stanford, CA 94305-5484, USA
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  • Cheryl L. Morse,

    1. PET Radiopharmaceutical Sciences Section, Molecular Imaging Branch, National Institute of Mental Health, National Institutes of Health, Building 10, Room B3 C346, 10 Center Drive, Bethesda, MD 20892-1003, USA
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  • H. Umesha Shetty,

    1. PET Radiopharmaceutical Sciences Section, Molecular Imaging Branch, National Institute of Mental Health, National Institutes of Health, Building 10, Room B3 C346, 10 Center Drive, Bethesda, MD 20892-1003, USA
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  • Victor W. Pike

    1. PET Radiopharmaceutical Sciences Section, Molecular Imaging Branch, National Institute of Mental Health, National Institutes of Health, Building 10, Room B3 C346, 10 Center Drive, Bethesda, MD 20892-1003, USA
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Abstract

[18F]SPA-RQ is an effective radioligand for imaging brain neurokinin type-1 (NK1) receptors in clinical research and drug discovery with positron emission tomography. For the automated regular production of [18F]SPA-RQ for clinical use in the USA under an IND we chose to use a modified commercial synthesis module (TRACERlab FXF-N; GE Medical Systems) with an auxiliary custom-made robotic cooling–heating reactor, after evaluating several alternative radiosynthesis conditions. The automated radiosynthesis and its quality control are described here. [18F]SPA-RQ was regularly obtained within 150 min from the start of radiosynthesis in high radiochemical purity (>99%) and chemical purity and with an overall decay-corrected radiochemical yield of 15±2% (mean±S.D.; n=10) from cyclotron-produced [18F]fluoride ion. The specific radioactivity of [18F]SPA-RQ at the end of synthesis ranged from 644 to 2140 mCi/µmol (23.8–79.2 GBq/µmol). Copyright © 2005 John Wiley & Sons, Ltd.

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