sup 64^Cu- and ^sup 68^Ga-Labelled [Nle^sup 14^,Lys^sup 40^(Ahx-NODAGA)NH2]-Exendin-4 for Pancreatic Beta Cell Imaging in Rats

• Published in: Molecular imaging and biology 2014-04, Vol.16 (2), p.255
• Main Authors: Kirsi, Mikkola, Cheng-bin, Yim, Veronica, Fagerholm, Tamiko, Ishizu, Viki-veikko, Elomaa, Johan, Rajander, Jori, Jurttila, Tiina, Saanijoki, Tuula, Tolvanen, Marko, Tirri, Eleni, Gourni, Martin, Béhé, Martin, Gotthardt, Claude, Reubi Jean, Helmut, Mäcke, Anne, Roivainen, Olof, Solin, Pirjo, Nuutila
• Format: Article
• Language: English
• ISSN: 1536-1632; 1860-2002
• DOI: 10.1007/s11307-013-0691-2

Glucagon-like peptide-1 receptor (GLP-1R) is a molecular target for imaging of pancreatic beta cells. We compared the ability of [Nle^sup 14^,Lys^sup 40^(Ahx-NODAGA-^sup 64^Cu)NH2]-exendin-4 ([^sup 64^Cu]NODAGA-exendin-4) and [Nle^sup 14^,Lys^sup 40^(Ahx-NODAGA-^sup 68^Ga)NH2]-exendin-4 ([^sup 68^Ga]NODAGA-exendin-4) to detect native pancreatic islets in rodents. 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. 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 [^sup 64^Cu]NODAGA-exendin-4 and [^sup 68^Ga]NODAGA-exendin-4 were 0.144 and 0.012 mSv/MBq, respectively. [^sup 64^Cu]NODAGA-exendin-4 might be more effective for labelling islets than [^sup 68^Ga]NODAGA-exendin-4. This is probably due to the lower specific radioactivity of [^sup 68^Ga]NODAGA-exendin-4 compared to [^sup 64^Cu]NODAGA-exendin-4. The radiation dose in the kidneys may limit the use of [^sup 64^Cu]NODAGA-exendin-4 as a clinical tracer.[PUBLICATION ABSTRACT] Erratum DOI: 10.1007/s11307-013-0691-2