1. Department of Pediatrics, Korea University Anam Hospital, Korea University College of Medicine, Seoul, Korea.
2. Department of Radiation Oncology, Ajou University School of Medicine, Suwon, Korea.
3. Department of Biomedical Informatics, Ajou University School of Medicine, Suwon, Korea.
4. Office of Biostatistics, Ajou Research Institute for Innovative Medicine, Suwon, Korea.