One of the greatest challenges for modern radiotherapy is ventilation causing motion of tumours and surrounding healthy structures. Technically, modern radiation delivery systems enable in principle very accurate radiation targeting of the tumour and avoiding radiation damage to healthy tissue. However, to deliver sufficient dose to a continuously and irregularly moving tumour, it is necessary to irradiate the tumour with a large margin. Currently such a large margin means irradiating a volume of healthy tissue that is about equal to that of the tumour itself. The healthy tissue damage is itself problematic. But it also prohibits further raising the radiation dose to the tumour to enhance the probability of tumour destruction and thus patient survival. I have invented the use of non-invasive mechanical ventilators to revolutionise radiotherapy delivery, by prolonging breath-hold duration beyond 5 minutes and by reducing and regularising breathing movements. I have demonstrated this works with breast cancer patients. To support its clinical adoption it is now necessary to train other staff to use mechanical ventilation, demonstrate it works with other cancer patient groups, measure the reductions in internal movement of tumours and healthy structures, show how these would produce superior treatment plans and that all this works in another European hospital. My career goal is for me to use the evidence derived from the fellowship to fund the introduction of non-invasive mechanical ventilators first back in our own department (Birmingham, UK), then for me to lead a multi-centre evaluation trial across Europe and finally to lead its introduction into radiotherapy practice throughout Europe.