1. Department of Radiology and Research Institute of Radiology, University of Ulsan College of Medicine, Asan Medical Center, Seoul 138-736, Korea.
2. Medical Engineering R&D Center, Asan Medical Center, Seoul 138-736, Korea.
3. R&D Department, Coreline Soft, Co. Ltd., Seoul 137-897, Korea.
4. Interdisciplinary Program in Radiation Applied Life Science, Seoul National University College of Medicine, Seoul 110-744, Korea.