1. Department of Oncology, Western University, London Health Sciences Centre, London, Ontario, Canada
2. Department of Radiation Oncology, University of Toronto, Sunnybrook Health Sciences Centre, Toronto, Ontario, Canada
3. Department of Radiotherapy, Erasmus Medical Center, Rotterdam, the Netherlands
4. Department of Oncology, University of Alberta, Edmonton, Alberta, Canada
5. Department of Radiation Oncology, University of Toronto, Princess Margaret Cancer Centre, Toronto, Ontario, Canada
6. Grand River Regional Cancer Centre, Kitchener, Ontario, Canada
7. Department of Radiation Oncology, Dalhousie University, Halifax, Nova Scotia, Canada
8. Department of Radiation Oncology, University of Toronto, Credit Valley Cancer Centre, Mississauga, Ontario, Canada