1. Department of Nuclear Medicine and Radiology, Institute of Development, Aging and Cancer, Tohoku University, Sendai, Miyagi, Japan
2. Department of Nuclear Medicine and Radiology, Institute of Development, Aging and Cancer, Tohoku Univerisity, Sendai, Miyagi, Japan
3. Department of Geriatric Medicine and Neuroimaging, Tohoku University Hospital, Sendai, Miyagi, Japan