1. Department of Radiation Oncology, The University of Texas MD Anderson Cancer Center, Houston, TX;
2. Department of Radiation Oncology, University of Florida, Jacksonville, FL;
3. Department of Radiation Oncology, University of Pennsylvania, Philadelphia, PA;
4. Department of Radiation Physics, University of Louisiana, Baton Rouge, LA;
5. Proton Therapy Department, Proton Therapy Center Czech, Prague, Czech Republic;
6. Department of Oncology, Charles University in Prague and Motol University Hospital, Prague, Czech Republic;
7. Department of Radiation Physics, The University of Texas MD Anderson Cancer Center, Houston, TX;
8. Department of Radiation Oncology, Guy's and St. Thomas' Hospital, London, United Kingdom;
9. Department of Radiation Oncology, Institut Curie, Paris, France;
10. Department of Oncology, Rigshospitalet, Copenhagen University Hospital, Copenhagen, Denmark; and
11. Department of Radiation Oncology, Memorial Sloan Kettering Cancer Center, New York, NY