[1] Houston Methodist Hosp, Canc Ctr & Res Inst, Weil Cornell Med Coll, Dept Radiat Oncol, 6565 Fannin,Ste DB1-077, Houston, TX 77030 USA
[2] Univ Texas Med Branch, Dept Radiat Oncol, Galveston, TX 77555 USA
[3] Houston Methodist Hosp, Ctr Canc, Thorac Med Oncol, Houston, TX 77030 USA