64Cu- and 68Ga-Labelled [Nle14,Lys40(Ahx-NODAGA)NH2]-Exendin-4 for Pancreatic Beta Cell Imaging in Rats

Mikkola Kirsi, Cheng-Bin Yim, Fagerholm Veronica, Ishizu Tamiko, Viki-Veikko Elomaa, Johan Rajander, Jurttila Jori, Saanijoki Tiina, Tolvanen Tuula, Tirri Marko, Gourni Eleni, Béhé Martin, Gotthardt Martin, Reubi Jean Claude, Mäcke Helmut, Roivainen Anne, Olof Solin, Nuutila Pirjo

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    Abstract

    Purpose

    Glucagon-like peptide-1 receptor (GLP-1R) is a molecular target for imaging of pancreatic beta cells. We compared the ability of [Nle14,Lys40(Ahx-NODAGA-64Cu)NH2]-exendin-4 ([64Cu]NODAGA-exendin-4) and [Nle14,Lys40(Ahx-NODAGA-68Ga)NH2]-exendin-4 ([68Ga]NODAGA-exendin-4) to detect native pancreatic islets in rodents.

    Procedures

    The stability, lipophilicity and affinity of the radiotracers to the GLP-1R were determined in vitro. The biodistribution of the tracers was assessed using autoradiography, ex vivo biodistribution and PET imaging. Estimates for human radiation dosimetry were calculated.

    Results

    We found GLP-1R-specific labelling of pancreatic islets. However, the pancreas could not be visualised in PET images. The highest uptake of the tracers was observed in the kidneys. Effective dose estimates for [64Cu]NODAGA-exendin-4 and [68Ga]NODAGA-exendin-4 were 0.144 and 0.012 mSv/MBq, respectively.

    Conclusion

    [64Cu]NODAGA-exendin-4 might be more effective for labelling islets than [68Ga]NODAGA-exendin-4. This is probably due to the lower specific radioactivity of [68Ga]NODAGA-exendin-4 compared to [64Cu]NODAGA-exendin-4. The radiation dose in the kidneys may limit the use of [64Cu]NODAGA-exendin-4 as a clinical tracer.

    Original languageUndefined/Unknown
    Pages (from-to)255–263
    JournalMolecular Imaging and Biology
    Volume16
    Issue number2
    DOIs
    Publication statusPublished - 2014
    MoE publication typeA1 Journal article-refereed

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