1 Division Medical Radiation Physics, Department of Radiation Oncology, Medical University of Vienna, Austria; MedAustron Ion Therapy Center, Wiener Neustadt, Austria. Electronic address: Dietmar.Georg@meduniwien.ac.at.
2 Division of Cancer Sciences, Faculty of Biology, Medicine and Health, The University of Manchester, United Kingdom; The Christie NHS Foundation Trust, United Kingdom.
3 Department of Radiation Oncology, the Netherlands Cancer Institute, Amsterdam, the Netherlands; Department of Radiation Oncology, Leiden University Medical Center, Leiden, the Netherlands.
4 Institute of Medical Physics, School of Physics, University of Sydney, Australia; Radiotherapy Research Group, St James's Hospital and University of Leeds, United Kingdom.