[1] Aarhus Univ Hosp, Aarhus, Denmark
[2] Med Univ Vienna, Vienna, Austria
[3] Tata Mem Hosp, Dept Radiat Oncol, Bombay, Maharashtra, India
[4] Univ Med Ctr Utrecht, Utrecht, Netherlands
[5] Mt Vernon Hosp, Ctr Canc, Northwood, Middx, England
[6] Inst Oncol, Dept Radiotherapy, Ljubljana, Slovenia
[7] Gustave Roussy, Dept Radiat Oncol, Villejuif, France
[8] Med Univ Vienna, Ctr Comprehens Canc, Dept Radiat Oncol, Vienna, Austria
[9] Aarhus Univ Hosp, Dept Oncol, Aarhus, Denmark