64Cu- and 68Ga-Labelled [Nle14,Lys40(Ahx-NODAGA)NH2]-Exendin-4 for Pancreatic Beta Cell Imaging in Rats
: Imaging Beta Cells with 64Cu- and 68Ga-Labelled NODAGA-Exendin-4
: Mikkola Kirsi, Yim Cheng-Bin, Fagerholm Veronica, Ishizu Tamiko, Elomaa Viki-Veikko, Rajander Johan, Jurttila Jori, Saanijoki Tiina, Tolvanen Tuula, Tirri Marko, Gourni Eleni, Béhé Martin, Gotthardt Martin, Reubi Jean Claude, Mäcke Helmut, Roivainen Anne, Solin Olof, Nuutila Pirjo
Publisher: Springer US
: 2014
: Molecular Imaging and Biology
: MIB
: 16
: 2
: 255
: 263
: 9
: 1536-1632
: 1860-2002
DOI: https://doi.org/10.1007/s11307-013-0691-2
: http://link.springer.com/article/10.1007/s11307-013-0691-2
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.
