Yulin He, Wei-na Zhou, Xiangcheng Wang
Jun 25, 2015
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Journal
Chinese Journal of Nuclear Medicine and Molecular Imaging
Abstract
Objective To synthesize 11C-methyldopamine (MDA) and to explore its feasibility as an agent for cardiac sympathetic nerve imaging. Methods 11C-MDA was synthesized by direct N-methylation method and purified by semi-preparation reverse HPLC. Thirty Kunming mice were divided into five groups by random number table. The mice were respectively sacrificed at 2, 5, 10, 20 and 30 min after injection of 7.4 MBq 11C-MDA. The lung, liver, spleen, kidney, stomach, intestine, brain, muscle, bone tissues and blood of mice were removed and weighed before radioactive γ-counting. The %ID/g was calculated. Six Chinese mini-swine were divided into normal group (n=3) and inhibition group (n=3) for myocardial imaging. Mini-swine of inhibition group were injected with 10 mg/kg imipramine hydrochloride at 30 min before 11C-MDA (370 MBq) injection. The data were analyzed with SPSS 15.0 software. Results The synthesis of 11C-MDA took 45 min with radiochemical yields of (20±3)%. The solution of 11C-MDA was colorless and the pH value was 6.5. The radiochemical purity was more than 98% and the specific activity was 50 GBq/mmol. The myocardial uptake reached the peak value of (8.78±1.18) %ID/g at 2 min after injection of 11C-MDA in mice. 11C-MDA was mainly metabolized through liver and kidney. PET/CT imaging showed that 11C-MDA was highly uptaken in swine myocardium and could be blocked by imipramine hydrochloride. Conclusions 11C-MDA can be synthesized by a simple and economic method. The high uptake rate of 11C-MDA in the heart suggests it may be a potential agent for cardiac nerve imaging. Key words: Dopamine; Isotope labeling; Carbon radioisotopes; Chemical synthesis; Mice; Swine