Abstract
Purpose: The future significance of peptide radiopharmaceuticals in diagnostic imaging with PET will be dependent on methodological aspects, as well as other requirements such as availability of the radionuclide and cost-effectiveness of its production. The aim of this study was to evaluate whether recent improvements in the modification of peptide pharmacokinetics by carbohydration may open a niche for the use of 11C-labelled peptide receptor binding tracers. Methods: A carbohydrated analogue of Tyr 3-octreotate was used as a clinically relevant peptide. Oxime-mediated coupling between 4-[11C]methoxy-benzaldehyde and an aminooxy-conjugated peptide precursor provided the 11C-labelled peptide in 21±5% decay-corrected yield (n=4) in a synthesis time of about 1 h. Results: In rat pancreas carcinoma xenografted mice, the compound displayed predominant and fast renal clearance combined with high tumour uptake (18.5±2.8% ID/g) at 30 min post injection. Corresponding values for kidney, liver and intestine were 18.5±2.4% ID/g, 3.2±0.5% ID/g and 2.1±0.3% ID/g, respectively. In a PET study with xenografted mice, the tumour (0.2-0.3 g) was clearly delineated as early as 20 min after injection. Somatostatin receptor (sstr)-specific uptake was demonstrated by reduction of tumour uptake to 20% of control by co-injection of TOC (0.4 mg/kg; 30 min p.i.). Conclusion: A 11C-labelled octreotate derivative has been prepared which shows suitable pharmacokinetics for in vivo imaging of sstr-overexpressing tumours and thus represents the first proof of principle for the potential of 11C-labelled peptides in tumour imaging.
Original language | English |
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Pages (from-to) | 1653-1657 |
Number of pages | 5 |
Journal | European Journal of Nuclear Medicine and Molecular Imaging |
Volume | 31 |
Issue number | 12 |
DOIs | |
State | Published - Dec 2004 |
Keywords
- Carbon-11
- Octreotate
- Octreotide
- PET
- Somatostatin receptor