1 Department of Radiation Oncology, The University of Texas MD Anderson Cancer, Houston, Texas; Department of Radiation Medicine, Oregon Health & Science University, Oregon. Electronic address: cdfuller@mdanderson.org.
2 Department of Radiation Oncology, The University of Texas MD Anderson Cancer, Houston, Texas; Department of Radiation Oncology, University Medical Center- Groningen, Groningen, Netherlands.
3 Department of Radiation Medicine, Oregon Health & Science University, Oregon.
4 Department of Radiation Oncology, Taussig Cancer Institute, Cleveland Clinic, Cleveland, Ohio.
5 Department of Radiation Oncology, The University of Texas MD Anderson Cancer, Houston, Texas.