[1] Tohoku Univ, Inst Dev Aging & Canc, Div Neuroimaging, Aoba Ku, 4-1 Seiryo Machi, Sendai, Miyagi 9808575, Japan
[2] Tohoku Univ, Sch Med, Dept Pharmacol, Aoba Ku, 2-1 Seiryo Machi, Sendai, Miyagi 9808575, Japan
[3] Tohoku Univ, Ctr Cyclotron & Radioisotope, Div Radiopharmaceut Chem, Aoba Ku, 6-3Aoba, Sendai, Miyagi 9808578, Japan
[4] Tohoku Univ, Inst Dev Aging & Canc, Dept Geriatr & Gerontol, Aoba Ku, 4-1 Seiryo Machi, Sendai, Miyagi 9808575, Japan