[1] Univ British Columbia, Vancouver, BC, Canada
[2] BC Canc, Vancouver, BC, Canada
[3] Emma Childrens Hosp, Acad Med Ctr, Dept Pediat Oncol, Amsterdam, Netherlands
[4] Univ Amsterdam, Acad Med Ctr, Amsterdam, Netherlands
[5] Fdn IRCCS, Ist Nazl Tumori, Prostate Canc Program, Milan, Italy
[6] IRCCS, Ctr Riferimento Oncol Aviano, Div Med Phys, Aviano, Italy
[7] Karolinska Univ Hosp, Stockholm, Sweden
[8] Emma Childrens Hosp, Acad Med Ctr, Amsterdam, Netherlands
[9] Univ Rochester, Med Ctr, Dept Radiat Oncol, Rochester, NY 14642 USA
[10] Brigham & Womens Hosp, Dept Radiat Oncol, 75 Francis St, Boston, MA 02115 USA