1. Department of Oncology, Oslo University Hospital, Oslo, Norway;
2. Department of Public Health and Nursing, Norwegian University of Science and Technology, Trondheim, Norway;
3. Department of Medical Physics, Oslo University Hospital, Oslo, Norway;
4. Department of Gastrointestinal and Paediatric Surgery, Oslo University Hospital, Oslo, Norway;
5. Department of Physics, University of Oslo, Oslo, Norway;
6. K.G. Jebsen Colorectal Cancer Research Centre, Oslo University Hospital, Oslo, Norway