[1] Thomas Jefferson Univ, Philadelphia, PA 19107 USA
[2] Radiat Oncol Associates Northern Virginia, Philadelphia, PA USA
[3] Thomas Jefferson Univ Hosp, Philadelphia, PA 19107 USA
[4] Ohio State Univ, James Canc Hosp, Wexner Med Ctr, Columbus, OH 43210 USA
[5] Thomas Jefferson Univ, Dept Radiat Oncol, Philadelphia, PA 19107 USA