1 Department of Radiation Oncology, Charité Universitätsmedizin Berlin, Berlin 13353, Germany. Electronic address: pirus.ghadjar@charite.de.
2 Department of Radiation Oncology, Heidelberg University Hospital, Heidelberg, Germany.
3 Department of Radiotherapy, Radiation Oncology, Faculty of Medicine, University Hospital Carl Gustav Carus, Technische Universität Dresden, Dresden, Germany.