[1] Emory Univ, Winship Canc Inst, Dept Radiat Oncol, Atlanta, GA 30322 USA
[2] Univ Cape Town, Groote Schuur Hosp, Dept Radiat Oncol, Cape Town, South Africa
[3] Univ Med Ctr Utrecht, Princess Maxima Ctr Pediat Oncol, Utrecht, Netherlands
[4] Univ Nebraska, Univ Nebraska Med Ctr, Dept Radiat Oncol, Omaha, NE 68182 USA
[5] Univ Southern Calif, Childrens Hosp Los Angeles, Dept Radiat Oncol, Los Angeles, CA 90007 USA
[6] Cairo Univ, Childrens Canc Hosp, Natl Canc Inst, Cairo, Egypt
[7] Barretos Canc Hosp, Dept Radiat Oncol, Barretos, SP, Brazil
[8] Harvard Univ, Massachusetts Gen Hosp, Dept Radiat Oncol, Boston, MA 02115 USA