1. Department of Radiation Oncology, National Hospital Organization Shikoku Cancer Center, Matsuyama, Ehime 791‑0280, Japan
2. Department of Radiology, Ehime University Graduate School of Medicine, Toon, Ehime 791‑0295, Japan
3. Department of Thoracic Oncology and Medicine, National Hospital Organization Shikoku Cancer Center, Matsuyama, Ehime 791‑0280, Japan