1 Department of Radiation Oncology, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina. Electronic address: panayiotis_mavroidis@med.unc.edu.
2 Department of Radiation Oncology, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina; Department of Radiation Oncology, Wake Forest University, Winston-Salem, North Carolina.
3 Department of Radiation Oncology, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina; Department of Radiation Oncology, University of Kansas, Kansas City, Kansas.