1. Department of Radiology, Kobe University Graduate School of Medicine, Kobe, Hyogo 650-0017, Japan
2. Division of Rehabilitation Medicine, Kobe University Graduate School of Medicine, Kobe, Hyogo 650-0017, Japan
3. Department of Tracer Kinetics and Nuclear Medicine, Osaka University Graduate School of Medicine, Suita, Osaka 565-0871, Japan