Tumor accumulation of S-adenosyl-L-[methyl-11C]methionine ([11C]SAM) was investigated in mice bearing mammary carcinoma (FM3A) and in rats bearing ascitic hepatoma (AH109A). After injection of [11C]SAM the blood clearance of 11C radioactivity was rapid. The 11C level was relatively high in both tumors. The uptake ratios of tumor to organ increased with time in several organs, especially in brai...

R-(-)-[11C]Epinephrine ([11C]EPI) has been synthesized from R-(-)-norepinephrine by direct methylation with [11C]methyl iodide or [11C]methyl triflate. The total synthesis time including HPLC purification was 35-40 min. The radiochemical yields (EOB) were 5-10% for [11C]methyl iodide and 15-25% for [11C]methyl triflate. Radiochemical purity was > 98%; optical purity determined by radio-chiral H...

UNLABELLED Dopamine D2 receptor function was assessed in a PET study with 2 dopamine D2 receptor PET ligands, [11C]raclopride (RAC) and [11C]N-methylspiperone (NMSP), in early Parkinson's disease. METHODS Seven patients with early Parkinson's disease and 5 healthy volunteers were studied. Each underwent PET both with reversible [11C]RAC and with irreversible [11C]NMSP. RESULTS Upregulation ...

We have evaluated the feasibility of using four positron emission tomography (PET) tracers for imaging the globus pallidus by ex vivo autoradiography in rats. The tracers investigated were [11C]KF18446, [11C]SCH 23390 and [11C]raclopride for mapping adenosine A2A, dopamine D1 and dopamine D2 receptors, respectively, and [18F]FDG. The highest uptake by the globus pallidus was found for [11C]SCH ...

Recently we have clinically used three new radioligands, [11C]SA4503, [11C]MPDX, and [11C]TMSX, for mapping sigma1, adenosine A1, and adenosine A2A receptors, respectively, in the human brain by positron emission tomography. These radioligands are synthesized by methylation of the respective demethyl precursor with [11C]methyl iodide. Here we demonstrate the improved syntheses of these compound...

The development of a novel electrochemical methodology to generate carbon-11 carbon monoxide ([11C]CO) from cyclotron-produced carbon-11 carbon dioxide ([11C]CO2) using Ni(cyclam) and Zn(cyclen) complexes is described. This methodology allows up to 10% yields of [11C]CO from [11C]CO2. Produced [11C]CO was subsequently converted to [11C]N-benzylbenzamide under mild conditions with a radiochemica...

BACKGROUND Using positron emission tomography (PET), we compared two tracers, [11C]metomidate ([11C]MTO) and [11C]acetate ([11C]ACE), for the characterization of hepatic tumors. METHODS Thirty-three patients underwent PET with [11C]MTO and [11C]ACE and magnetic resonance imaging (MRI). Based on the histology of the tumor biopsy, 14 patients had hepatocellular carcinoma (HCC), 9 patients had f...

Background [11C]Cimbi-36 is a serotonin 2A receptor agonist positron emission tomography radioligand that has recently been examined in humans. The binding of agonist radioligand is expected to be more sensitive to endogenous neurotransmitter concentrations than antagonist radioligands. In the current study, we compared the effect of serotonin releaser fenfluramine on the binding of [11C]Cimbi-...

We prepared 11C-labeled 5-(4-chlorophenyl)-1-(4-methoxyphenyl)-3-(trifluoromethyl)-1H-pyrazole ([11C]1) and 4-[5-(4-methoxyphenyl)-3-trifluoromethyl-1H-pyrazol-1-yl]benzenesulfonamide ([11C]2) for imaging COX-1 and COX-2 isoforms, respectively, by positron emission tomography. [11C]1 and [11C]2 were synthesized in high radiochemical yields by O-[11C]methylation with [11C]methyl triflate in acet...

In the early 1990s, 9-(+)-11C-dihydrotetrabenazine (9-(+)-11C-DTBZ) was shown to be a useful positron emission tomography (PET) imaging agent for various neurodegenerative disorders. Here, we described the radiosynthesis and evaluation of the 9-(+)-11C-DTBZ analog, 10-(+)-11C-DTBZ, as a vesicular monoamine transporter 2 (VMAT2) imaging agent and compare it with 9-(+)-11C-DTBZ. 10-(+)-11C-DTBZ w...