Figure 7 - uploaded by Olof Eriksson
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![Structural formula for [ 18 F]FE-(+)-DTBZ. The hydrocarbon (in this case ethyl) group containing the positron emitting fluorine-18 nuclide is covalently bound to the oxygen atom at the top left. The in vivo kinetics of the tracer can be modified by changing this group into another hydrocarbon, such as a methyl-or a propylgroup. In the case of [ 18 F]FE-(+)-DTBZ-d 4 , the hydrogen atoms (protium isotopes, 1 H, containing no neutrons) bound to the ethyl carbons are replaced by deuterium isotopes ( 2 H, containing one neutron).](profile/Olof-Eriksson/publication/277845076/figure/fig7/AS:668445758738443@1536381296501/Structural-formula-for-18-FFE--DTBZ-The-hydrocarbon-in-this-case-ethyl-group.png)
Structural formula for [ 18 F]FE-(+)-DTBZ. The hydrocarbon (in this case ethyl) group containing the positron emitting fluorine-18 nuclide is covalently bound to the oxygen atom at the top left. The in vivo kinetics of the tracer can be modified by changing this group into another hydrocarbon, such as a methyl-or a propylgroup. In the case of [ 18 F]FE-(+)-DTBZ-d 4 , the hydrogen atoms (protium isotopes, 1 H, containing no neutrons) bound to the ethyl carbons are replaced by deuterium isotopes ( 2 H, containing one neutron).
Citations
... We know from quantitative prelabeling techniques that islets tend to cluster in small hepatic foci rather than spread out homogenously across the liver in humans, which is possibly due to thrombosis (2,3). Furthermore, transplanted islet homogeneity in hepatic distribution can be shown to differ between human subjects (13). Therefore, the hotspot SUV readout from the [ 11 C]5-HTP examination may be biased toward identifying more islets in subjects with IPX with more pronounced hepatic heterogeneity, which further points to the importance of low hepatic background for this type of application. ...
There currently exists no imaging methodology to monitor viable islet mass following clinical intraportal islet transplantation. We investigated the potential of the endocrine positron emission tomography (PET) marker [(11)C]5-hydroxy-tryptophan ([(11)C]5-HTP) for this purpose. In a preclinical proof of concept study, the ex vivo and in vivo [(11)C]5-HTP signal was compared to the number of islets transplanted in rats. In a clinical study, human subjects with an intraportal islet graft (n=8) performed two [(11)C]5-HTP PET and MRI examinations 8 months apart. The tracer concentration in the liver as a whole, or in defined hotspots was correlated to measurements of islet graft function. In rat, hepatic uptake of [(11)C]5-HTP correlated with number of transplanted islets. In human subjects, uptake in hepatic hotspots showed a correlation with metabolic assessments of islet function. Change in hotspot SUV predicted loss of graft function in one subject whereas hotspot SUV was unchanged in subjects with stable graft function. The endocrine marker [(11)C]5-HTP thus show correlation between hepatic uptake and transplanted islet function, and show promise as a tool for non-invasive detection of viable islets. The evaluation procedure described herein can be used as benchmark for novel agents targeting intraportally transplanted islets.
