1 Department of Nuclear Medicine, Samsung Changwon Hospital, Sungkyunkwan University School of Medicine, Changwon, Korea (the Republic of).
2 Department of Electronic Engineering, Pai Chai University, Daejeon, Korea (the Republic of).
3 Department of Neurology, Pusan National University Hospital, Busan, Korea (the Republic of).
4 Dept. of Nuclear Medicine and Biomedical Research Institute, Pusan National University Hospital and School of Medicine, Pusan National University, Busan, Republic of Korea.