1. Department of Radiation Oncology, Amsterdam UMC, University of Amsterdam, Cancer Center Amsterdam, Amsterdam, The Netherlands;
2. Department of Gastroenterology and Hepatology, Amsterdam UMC, University of Amsterdam, Amsterdam, The Netherlands;
3. Department of Biomedical Engineering and Physics, Academic Medical Center, Amsterdam, The Netherlands;
4. Department of Physics and Astronomy, Institute for Laser Life and Biophotonics Amsterdam, Amsterdam, The Netherlands;
5. Department of Radiation Oncology, Radiotherapy Institute Friesland, Leeuwarden, The Netherlands;
6. The Christie NHS Foundation Trust, University of Manchester Institute of Cancer Sciences, Manchester, United Kingdom