Development of a noninvasive and quantitative method for measuring the efflux rate of thiocyanate from the brain and elucidation of its efflux mechanism

2022 Fiscal Year Final Research Report

• Project/Area Number: 19K08241
• Research Category: Grant-in-Aid for Scientific Research (C)
• Allocation Type: Multi-year Fund
• Section: 一般
• Review Section: Basic Section 52040:Radiological sciences-related
• Research Institution: National Institutes for Quantum Science and Technology
• Principal Investigator: OKAMURA Toshimitsu 国立研究開発法人量子科学技術研究開発機構, 量子医科学研究所 先進核医学基盤研究部, 主任研究員 (80443068)
• Project Period (FY): 2019-04-01 – 2023-03-31
• Keywords: PET / チオシアン酸イオン / 脳

Outline of Final Research Achievements

The purpose of this study was to develop a noninvasive and quantitative method for measuring the efflux rate of thiocyanate from the brain and to elucidate its efflux mechanism. A 11C-labeled 6-thiocyanatopurine derivative ([11C]TP), designed as a candidate, entered the brain after intravenous administration and was converted to [11C]thiocyanate, which was then cleared from the brain. After the complete conversion of [11C]TP to [11C]thiocyanate, the decrease in brain radioactivity can be considered to reflect [11C]thiocyanate efflux from the brain. Perchlorate inhibited the efflux rate of [11C]thiocyanate in a dose-dependent manner, and the highest dose resulted in a markedly decrease in the efflux rate. Furthermore, the efflux rate of [11C]thiocyanate in the sodium iodide symporter (NIS) knockout mice was significantly lower than that of wild-type mice. Thus, the efflux rate of thiocyanate from the brain can be noninvasively and quantitatively measured by [11C]TP.

Free Research Field

放射線科学

Academic Significance and Societal Importance of the Research Achievements

本研究で開発されたトレーサを用いることによって、脳内のSCN-排出速度の測定が可能となった。これにより、脳内にSCN-を直接投与することなく、SCN-排出システムがどのように機能しているかを定量的に評価できるようになった。今後は、SCN-排出能に対する環境汚染物質の影響や、脳疾患におけるSCN-排出能を定量評価することで、脳の防御機構や病気の発症機構の解明につながることが期待される。