Optimization of the radiosynthesis of the Alzheimer tracer 2-(4-N-[11C]methylaminophenyl)-6-hydroxybenzothiazole ([11C]PIB)

[11C]PIB is still the standard PET compound for Alzheimer imaging targeting beta-amyloid plaques. We aimed to establish a fully-automated procedure for the synthesis and purification of [11C]PIB with a high degree of reliability and improved specific activity as well as a suitable and fast quality control assay. The optimum reaction conditions were 75 °C, 4 mg/mL precursor yielding at 48.0±2.7% (EOS, based on [11C]CH3OTf, corrected for decay), 183±14 GBq/μmol specific activity and >99% radiochemical purity. Time consumption was kept to a minimum (40 min from EOB) and overall yields were enough to serve 2 consecutive patients with a single preparation.

► Optimized radiosynthesis of [11C]PIB in 40 min.
► Optimum reaction conditions were 75 °C and 4 mg/mL precursor.
► Radiochemical yields were 4.2±1.1 GBq.
► The specific activity was 183±14 GBq/μmol.