[1] Catholic Univ Louvain, Dept Radiat Oncol, CHU UCL Namur, Site St Elisabeth, Namur, Belgium
[2] KU Leuven Univ Leuven, Dept Radiat Oncol, Leuven Canc Inst, Univ Hosp Leuven, Leuven, Belgium
[3] Ghent Univ Hosp, Radiotherapy Oncol, Ghent, Belgium
[4] Univ Ghent, Dept Radiotherapy & Expt Canc Res, Ghent, Belgium
[5] Catholic Univ Louvain, Sci Support Unit, CHU UCL Namur, Site Godinne, Yvoir, Belgium