Abstract | INTRODUCTION: METHODS: H(2)(15)O flow studies were performed in 8 CA20948 tumor-bearing rats and another 36 rats underwent three [(68)Ga]- DOTA- Tyr(3)-octreotate imaging sessions at 24-h intervals. After baseline (Day 0) imaging, scanning was repeated on Day 1 after octreotide injection (175 microg/kg), with a variable delay: no injection (controls, n=7), coinjection (n=6), and octreotide injection 20 min (n=7), 2 h (n=8) and 4 h (n=8) before imaging. Repeat images without octreotide was performed at Day 2 followed by sacrifice and tumor counting. RESULTS: H(2)(15)O studies failed to measure quantitative tumor perfusion in this model. On Day 1, ratio of tumor uptake to Day 0 was 1.2+/-0.3 in controls; 0.6+/-0.2 in the coinjection group; 0.9+/-0.2, 1.1+/-0.1 and 1.2+/-0.2 in the other groups, respectively. Uptake in the coinjection group showed a statistically significant reduction of tumor uptake (P<.0001). All groups showed increased uptake on Day 2, without statistical differences between groups. In vivo tumor counts showed good correlation with ex vivo countings (R(2)=0.946). CONCLUSION: Acute exposure to unlabeled octreotide in this neuroendocrine tumor model results in a rapid recycling or resynthesis of sstr. Positron emission tomography (PET) allowed to reliably assess quantitative uptake of [(68)Ga]- DOTA- Tyr(3)-octreotate over time in the same animal, but failed in this model to measure tumor perfusion.
|
Authors | François-Xavier Hanin, Stanislas Pauwels, Anne Bol, Wout Breeman, Marion de Jong, François Jamar |
Journal | Nuclear medicine and biology
(Nucl Med Biol)
Vol. 37
Issue 2
Pg. 157-65
(Feb 2010)
ISSN: 1872-9614 [Electronic] United States |
PMID | 20152715
(Publication Type: Journal Article)
|
Copyright | (c) 2010 Elsevier Inc. All rights reserved. |
Chemical References |
- DOTA-Tyr(1)-octreotate
- Gallium Radioisotopes
- Heterocyclic Compounds, 1-Ring
- Oxygen Radioisotopes
- Radioactive Tracers
- Receptors, Somatostatin
- Water
- Somatostatin
- somatostatin receptor 2
- Octreotide
|
Topics |
- Animals
- Biological Transport
(drug effects)
- Disease Models, Animal
- Gallium Radioisotopes
(chemistry)
- Half-Life
- Heterocyclic Compounds, 1-Ring
(chemistry, metabolism)
- Humans
- Male
- Neoplasms
(blood supply, diagnostic imaging, metabolism)
- Octreotide
(analogs & derivatives, chemistry, metabolism)
- Oxygen Radioisotopes
(chemistry)
- Positron-Emission Tomography
- Radioactive Tracers
- Rats
- Receptors, Somatostatin
(metabolism)
- Reproducibility of Results
- Somatostatin
(chemistry, metabolism)
- Water
(chemistry, metabolism)
|