1. Department of Radiology, Faculty of Medical Sciences, University of Fukui , 23-3, Matsuoka-shimoaizuki, Eiheiji, Yoshida, Fukui 910-1193 , Japan
2. Division of Radioisotope Experiments, Life Science Research Laboratory, University of Fukui , 23-3, Matsuoka-shimoaizuki, Eiheiji, Yoshida, Fukui 910-1193 , Japan
3. Faculty of Health Sciences, Institute of Medical, Pharmaceutical and Health Sciences, Kanazawa University , 5-11-80, Kodatsuno, Kanazawa, Ishikawa 920-0942 , Japan
4. Department of Radiology, Niigata Prefectural Central Hospital , 205, Shinnan, Joetsu, Niigata 943-0192 , Japan
5. Radiology Department, Toyama University Hospital , 2630, Sugitani, Toyama 930-0194 , Japan