타우 PET영상을 위한 18F-THK5351의 표지방법 개발

Abstract

Purpose 18F-THK5351 is the newly developed PET probe for tau imaging in alzheimer's disease. The purpose of study was to establish the automated production of 18F-THK5351 on a commercial module. Materials and Methods Two different approaches were evaluated for the synthesis of 18F-THK5351. The first approach (method I) included the nucleophilic $^{18}F$ -fluorination of the tosylate precursor, subsequently followed by pre-HPLC purification of crude reaction mixture with SPE cartridge. In the second approach (method II), the crude reaction mixture was directly introduced to a semi-preparative HPLC without SPE purification. The radiosynthesis of 18F-THK5351 was performed on a commercial GE $TRACERlab^{TM}$ $FX-_{FN}$ module. Quality control of 18F-THK5351 was carried out to meet the criteria guidelined in USP for PET radiopharmaceuticals. Results The overall radiochemical yield of method I was $23.8{\pm}1.9%$ (n=4) as the decay-corrected yield (end of synthesis, EOS) and the total synthesis time was $75{\pm}3min$ . The radiochemical yield of method II was $31.9{\pm}6.7%$ (decay-corrected, n=10) and the total preparation time was $70{\pm}2min$ . The radiochemical purity was>98%. Conclusion This study shows that method II provides higher radiochemical yield and shorter production time compared to the pre-SPE purification described in method I. The 18F-THK5351 synthesis by method II will be ideal for routine clinical application, considering short physical half-life of fluorine-18 ($t_{1/2}=110min$ ).