Development of a reliable remote-controlled synthesis of β-[11C]-5-hydroxy-L-tryptophan on a Zymark robotic system
✍ Scribed by O. C. Neels; P. L. Jager; K. P. Koopmans; E. Eriks; E. G. E. de Vries; I. P. Kema; P. H. Elsinga
- Publisher
- John Wiley and Sons
- Year
- 2006
- Tongue
- French
- Weight
- 119 KB
- Volume
- 49
- Category
- Article
- ISSN
- 0022-2135
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✦ Synopsis
Precise staging of neuroendocrine tumors (NET) using positron emission tomography (PET) tracers visualizing their specific metabolic activity is of interest. Besides [ 18 F]FDOPA, staging NET with carbon-11 labeled 5-hydroxytryptophan (5-HTP) is reported in recent literature. We implemented the multi-enzymatic synthesis of enantiomerically pure [ 11 C]-L-5-HTP on a Zymark robotic system to compare both tracers in patient studies. [ 11 C]-5-HTP can be synthesized in up to 24% radiochemical yields (EOB). Average specific activity is 44 000 GBq/mmol in ca. 50 min from [ 11 C]methyl iodide in radiochemical purities >99 %. The synthesis of 5-HTP is difficult due to its multi-enzymatic reaction steps but typical yields can be achieved of ca. 400 MBq. [ 11 C]-5-HTP is now reliably used in ongoing studies for staging NET.