Automated Synthesis of ¹⁸F-AV45 for Aβ-Amyloid Imaging and its Preliminary Clinical Application

Aβ-Amyloid positron imaging agent 18F-AV45 was synthesized automatically using TRACERlab FX2 N radiosynthesis module and the clinical imaging of ¹⁸F-AV45 was evaluated. AV105 was used as the precursor, which reacted with 18F ion at 130 ℃ for 10 minutes on the TRACERlab FX2 N, followed by acid hydrolysis and neutralization with NaOH, and then the reaction mixture was separated by high-performance liquid chromatography (HPLC) method to obtain the target compound ¹⁸F-AV45, which was next purified by solid-phase extraction method. The HPLC quality control analysis of the final ¹⁸F-AV45 injection was carried out. The radiochemical purity of ¹⁸F-AV45 was determined using a HPLC system equipped with a C18 column (InfinityLab Poroshell 120 EC-C1, 4 μm, 4.6 mm×100 mm) which was eluted with a mobile phase of acetonitrile/20 mM ammonium acetate (40∶60, v/v) at a flow rate of 1 mL/min. The absorbance of 350 nm and the radioactivity in the eluate flow were monitored with a diode array detector and a flow count detector, respectively. One case of patients with Alzheimer’s disease (AD) and one healthy person underwent ¹⁸F-AV45 PET/CT scanning. The results showed that it took 80 minutes from ¹⁸F ion to ¹⁸F-AV45, no-corrected efficiency was (17.02±1.52)%(n=6), radiochemistry purity was over 95%. The results of PET imaging showed that ¹⁸F-AV45 uptake was diffusely increased in the cerebral cortex of patient with AD, which indicated deposition of amyloid beta protein in cerebral cortex. And the results of imaging of the healthy person showed ¹⁸F-AV45 was no obvious uptake in cerebral cortex, namely, there was no deposition of amyloid beta protein in cerebral cortex. ¹⁸F-AV45 could be synthesized automatically and simply by TRACERlab FX2 N with good repeatability. The quality of ¹⁸F-AV45 injection meets the requirements for clinical use. In addition, ¹⁸F-AV45 has clinical application value in the diagnosis of patients with AD.