1. Department of Engineering Science, University of Oxford, Oxford OX1 3PJ, UK
2. Clinical Effectiveness and Evaluation Unit, Royal College of Physicians of London, London NW1 4LE, UK
3. Department of Respiratory Medicine, Glenfield Hospital, Leicester LE3 9QP, UK
4. Department of Clinical Radiology, Oxford University Hospitals NHS Trust, Oxford OX3 7LJ, UK
5. Mirada Medical, Oxford OX1 1BY, UK
6. Department of Oncology, University of Oxford, Oxford OX3 7DQ, UK