[1] Univ Med Ctr Utrecht, Dept Radiat Oncol, Utrecht, Netherlands
[2] Maria Sklodowska Curie Natl Res Inst Oncol, Dept Radiotherapy & Chemotherapy 3, Gliwice, Poland
[3] Champalimaud Ctr Unknown, Dept Radiat Oncol, Lisbon, Portugal
[4] Azienda Osped Univ Careggi, Dept Radiat Oncol, Florence, Italy
[5] Med Univ Lublin, Dept Radiotherapy, Lublin, Poland
[6] Univ Med Ctr Utrecht, Div Imaging & Oncol, Utrecht, Netherlands