1. Department of Radiation Oncology, Dana-Farber/Brigham and Women's Cancer Center, Boston, MA
2. Department of Radiation Oncology, MD Anderson Cancer Center, Houston, TX
3. Radiation Oncology Branch, National Cancer Institute, Bethesda, MD
4. Department of Radiation Oncology, University of Toronto, Princess Margaret Cancer Centre, Toronto, ON, Canada
5. Department of Radiation Oncology and Stanford Cancer Institute, Stanford University School of Medicine, Stanford, CA
6. Department of Radiation Oncology, Royal Marsden Hospital, London, United Kingdom
7. Department of Radiation Oncology, Medical College of Wisconsin, Milwaukee, WI
8. Department of Radiation Oncology, University of California, Irvine, Orange, CA
9. Department of Radiation Oncology, Mayo Clinic, Rochester, MN
10. St Luke's Radiation Oncology Network, Rathgar, Dublin, Ireland
11. Department of Radiotherapy, Leiden University Medical Center, Amsterdam, the Netherlands
12. Department of Radiation Oncology, Memorial Sloan Kettering Cancer Center, New York City, NY
13. Department of Radiotherapy, Netherlands Cancer Institute, Amsterdam, the Netherlands