1. Department of Radiology, Seoul National University College of Medicine, Institute of Radiation Medicine, Seoul National University Medical Research Center and Clinical Research Institute, Seoul National University Hospital, Seoul 110-744, Korea.
2. Department of Nuclear Medicine, Seoul National University College of Medicine, Seoul 110-744, Korea.
3. Department of Internal Medicine, Seoul National University College of Medicine, Seoul 110-744, Korea.
4. Biomedical Research Center, Korea Institute of Science and Technology, Seoul 139-774, Korea.
5. Department of Veterinary Radiology, Chonbuk National University College of Veterinary Medicine, Chonbuk 561-756, Korea.