1. Department of Radiation Oncology, Saiseikai Yokohamashi Tobu Hospital, Yokohama, Japan
2. Radiation Oncology Center, Ofuna Chuo Hospital, Kamakura, Japan
3. Department of Radiation Oncology, Tokai University School of Medicine, Isehara, Japan
4. Department of Thoracic Surgery, Saiseikai Yokohamashi Tobu Hospital, Yokohama, Japan