1. 1Division of Radiation Oncology, Vetsuisse Faculty, University of Zurich, Zurich, Switzerland.
2. 2Department of Radiation Oncology, Lausanne University Hospital and University of Lausanne, Lausanne, Switzerland.
3. 3Radiation Oncology Laboratory, Department of Radiation Oncology, Lausanne, University Hospital and University of Lausanne, Lausanne, Switzerland.
4. 4Institute of Radiation Physics, Department of Radiology, University Hospital and University of Lausanne, Lausanne, Switzerland.
5. 5Department of Radiation Oncology, School of Medicine, University of California at Irvine, Irvine, California.