1. Division of Imaging and Cancer, University Medical Center Utrecht, University of Utrecht, Utrecht, The Netherlands;
2. Division of Surgery, Department of Orthopaedics, University of Toronto, Toronto, Canada;
3. Division of Spine, Department of Orthopaedics, University of British Columbia and Vancouver General Hospital, Vancouver, British Columbia, Canada;
4. Department of Radiation Oncology, Sunnybrook Health Sciences Centre & Odette Cancer Centre, Toronto, Canada;
5. Department of Orthopaedic Surgery, University Medical Center Utrecht, Utrecht, The Netherlands