Abstract
Introduction
In this study, we assessed the whole-body biodistribution and radiation dosimetry of the new glutamatergic ligand 11C-ABP688. This ligand binds specifically to the metabotropic glutamatergic receptor of subtype 5 (mGluR5).
Materials and methods
The study included five healthy male volunteers aged 20-29 years. After intravenous injection of 240-260 MBq, a series of four to ten whole-body positron emission tomography/computed tomography scans were initiated, yielding 60-80 min of data. Residence times were then calculated in the relevant organs, and the software packages Mirdose and Olinda were used to calculate the absorbed radiation dose and the effective dose equivalent.
Results
Of the excreted 11C activity at 1 hour, approximately 80% were eliminated via the hepato-biliary pathway and 20% through the urinary tract. The absorbed dose (mGy/MBq) was highest in the liver (1.64 E -2 ± 5.08 E -3), gallbladder (8.13 E -3 ± 5.6 E -3), and kidneys (7.27 E -3 ± 2.79 E -3). The effective dose equivalent was 3.68 ± 0.84 microSv/MBq. Brain uptake in the areas with high mGluR5 density was 2-3 (SUV). The agreement between the values obtained from Mirdose and the Olinda was excellent.
Conclusion
11C-ABP688 is a very promising ligand for the investigation of mGluR5 receptors in humans. Brain uptake is high and the effective dose equivalent so low that serial examinations in the same subject seem feasible.
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Acknowledgment
Valerie Treyer was supported by the Swiss National Science Foundation. The study was sponsored by Novartis, Basel, and supported by the 51NF40-111381 (NCCR Neuro) and EU LSHM-CT-2003-503330 (APOPIS). We thank Esmeralda Gruber for the excellent clinical study support.
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Treyer, V., Streffer, J., Ametamey, S.M. et al. Radiation dosimetry and biodistribution of 11C-ABP688 measured in healthy volunteers. Eur J Nucl Med Mol Imaging 35, 766–770 (2008). https://doi.org/10.1007/s00259-007-0638-4
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DOI: https://doi.org/10.1007/s00259-007-0638-4