1. Hospital of the National Institute of Radiological Sciences, National Institutes for Quantum and Radiological Science and Technology, Chiba 263‑8555, Japan
2. Department of Radiation Effects Research, National Institutes for Quantum and Radiological Science and Technology, Chiba 263‑8555, Japan
3. National Institute of Radiological Sciences, National Institutes for Quantum and Radiological Science and Technology, Chiba 263‑8555, Japan
4. Department of Radiology, Jichi Medical University, Tochigi 329‑0498, Japan
5. Department of Radiation Oncology, Gunma University Graduate School of Medicine, Maebashi, Gunma 371‑8511, Japan
6. Department of Radiation Oncology, Saitama Medical University International Medical Center, Saitama 350‑1241, Japan