1. Oxford Institute for Radiation Oncology, University of Oxford, Old Road Campus Research Building, Roosevelt Drive, Oxford OX3 7DQ, U.K.
2. Institute of Cancer Sciences, Wolfson Wohl Cancer Research Centre, University of Glasgow, University Avenue, Glasgow G12 8QQ, U.K.
3. Charles River Laboratories, Elphinstone Research Centre, Elphinstone, Tranent EH33 2NE, U.K.
4. Institute of Biomedical Engineering, Department of Engineering Science, University of Oxford, Old Road Campus Research Building, Oxford OX3 7DQ, U.K.