Optimization of the Radiosynthesis of the 2-(4-N-[~(11)C]methylaminophenyl)-6-hydroxybenzothiazole for AD

11C-PIB was the standard PET radiopharmaceuticals for Alzheimer's disease(AD) imaging targeting beta-amyloid plaques.The optimization for high synthesis yield and specific activity was designed with 11CH3-Triflate as methylation agent for 11C-PIB.Synthesis for 11C-PIB were studied with home made carbon-11 synthesis module.The results showed that the amount of precursor,the temperature and pH could effect the labeling yield.The optimum reaction conditions were as fllows: with 5 g/L of precursor,pH=7.0,at room temperature,a yield of 65.2%±4.7%(n=8) and a specific activity of 70.6 GBq/g(18.0 TBq/mmol) were achieved,and radiochemical purity was over 99%.It took 30 min from 11CO2 to 11C-PIB.Single synthesis yielding was 3.7 GBq of 11C-PIB.The quantity and quality of 11C-PIB were suitable for clinical use after optimization.