Optimization of the Radiosynthesis of the 2-(4-N-¹¹Cmethylaminophenyl)-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.