1. Department of Radiation Oncology, The James Cancer Hospital at The Ohio State University Wexner Medical Center, Columbus, USA
2. Department of Oncology, McMaster University, Hamilton, Ontario, Canada
3. Department of Radiation Oncology, Mayo Clinic, Rochester, MN, USA
4. Department of Radiology, Mayo Clinic, Rochester, MN, USA
5. Department of Radiation Oncology, Centre Hospitalier de l’Université de Montréal, Quebec, Canada