University Hospital Zurich - Department of Radiation Oncology, affiliation not provided to SSRN, affiliation not provided to SSRN, affiliation not provided to SSRN, affiliation not provided to SSRN, La Tour Hospital, affiliation not provided to SSRN, affiliation not provided to SSRN, University Hospital Zurich - Department of Radiation Oncology, affiliation not provided to SSRN, affiliation not provided to SSRN, affiliation not provided to SSRN, affiliation not provided to SSRN, affiliation not provided to SSRN, University Hospital Zurich, University of Geneva - Geneva University Hospitals, Luzerner Kantonsspital, affiliation not provided to SSRN, University of Basel - University Hospital Basel, affiliation not provided to SSRN, Ente Ospedaliero Cantonale Bellinzona - Medical Physics Division, affiliation not provided to SSRN, affiliation not provided to SSRN, affiliation not provided to SSRN, University of Lausanne - Lausanne University Hospital, affiliation not provided to SSRN, University Hospital Zurich and University Hospital Zurich