1. Department of Radiation Oncology, University Medical Center Groningen, University of Groningen, 9700 RB Groningen, Netherlands.
2. Department of Cell Biology, University Medical Center Groningen, University of Groningen, 9713AV Groningen, Netherlands.
3. Radiation Oncology, Washington University School of Medicine, St. Louis, MO 63110, USA.
4. Department of Radiation Medicine and Applied Sciences, University of California San Diego, La Jolla, CA 92093, USA.
5. British Columbia Cancer Agency–Vancouver Centre, Vancouver, British Columbia V5Z 4E6, Canada.
6. Accelerator Department, Paul Scherrer Institut, CH-5212 Villigen, Switzerland.
7. KVI Center for Advanced Radiation Technology, University of Groningen, 9747 AA Groningen, Netherlands.