[1] Univ Hosp Zurich, Radiat Oncol, Zurich, Switzerland
[2] Univ Zurich, Fac Med, Zurich, Switzerland
[3] Iridium Netwerk, Antwerp, Belgium
[4] Univ Antwerp, Radiat Oncol, Antwerp, Belgium
[5] Univ Hosp Freiburg, Radiat Oncol, Freiburg, Germany
[6] Humanitas Clin Inst, Radiat Oncol, Milan, Italy
[7] Maria Sklodowska Curie Natl Res Inst Oncol, Radiat Oncol, Warsaw, Poland
[8] Kantonsspital Aarau, Radiat Oncol, Aarau, Switzerland
[9] Ente Osped Cantonale, Radiat Oncol, Bellinzona, Switzerland
[10] Minist Publ Hlth, Luxemburg Hlth Directorate, Luxembourg, Luxembourg
[11] Bern Univ Hosp, Inselspital, Radiat Oncol, Bern, Switzerland
[12] Univ Bern, Fac Med, Bern, Switzerland
[13] Univ Hosp Basel, Radiat Oncol, Basel, Switzerland
[14] Stadt Klinikum Dresden, Radiat Oncol, Dresden, Germany
[15] Geneva Univ Hosp, Radiat Oncol, Geneva, Switzerland
[16] Univ Hosp Modena, Radiat Oncol, Modena, Italy
[17] Kantonsspital Graubunden, Radiat Oncol, Chur, Switzerland
[18] Univ Hosp Leipzig, Radiat Oncol, Leipzig, Germany
[19] Hirslanden Clin, Radiat Oncol, Zurich, Switzerland
[20] Kantonsspital Winterthur, Radiat Oncol, Winterthur, Switzerland