1. Department of Internal Medicine, Yonsei University College of Medicine, Seoul, Korea.
2. Division of Endocrinology, Department of Internal Medicine, Dongsuwon General Hospital, Suwon, Korea.
3. Division of Nuclear Medicine, Department of Diagnostic Radiology, Yonsei University College of Medicine, Seoul, Korea.
4. Endocrine Research Institute, Yonsei University College of Medicine, Seoul, Korea.