[1] Vanderbilt Univ, Med Ctr, 221 Kirkland Hall, Nashville, TN 37235 USA
[2] UNC, Sch Med, Dept Radiat Oncol, Chapel Hill, NC USA
[3] UNC, Sch Med, Chapel Hill, NC USA
[4] UNC Hlth Care, UNC Med Ctr, Chapel Hill, NC USA
[5] UNC, Sch Med, UNC Lineberger Comprehens Canc Ctr, Chapel Hill, NC USA
[6] UNC, Sch Med, UNC Inst Healthcare Qual Improvement, Chapel Hill, NC USA
[7] UNC Med Ctr, Dept Radiat Oncol, Patient Safety & Qual, Chapel Hill, NC USA