1. Department of Proton Beam Therapy, Okayama University Graduate School of Medicine, Dentistry and Pharmaceutical Sciences, Okayama 700‑8558, Japan
2. Department of Radiology, Iwakuni Clinical Center, Iwakuni, Yamaguchi 740‑8510, Japan
3. Department of Radiology, Okayama Diagnostic Imaging Center, Okayama 700‑0913, Japan
4. Department of Radiology, Okayama University Hospital, Okayama 700‑8558, Japan
5. Department of Radiological Technology, Graduate School of Health Sciences, Okayama University, Okayama 700‑8558, Japan
6. Department of Allergy and Respiratory Medicine, Okayama University Hospital, Okayama 700‑8558, Japan
7. Department of Radiology, Okayama University Graduate School of Medicine, Dentistry and Pharmaceutical Sciences, Okayama 700‑8558, Japan
8. Department of General Thoracic Surgery and Breast and Endocrinological Surgery, Okayama University Graduate School of Medicine, Dentistry and Pharmaceutical Sciences, Okayama 700‑8558, Japan