Adaptive Cost Effective Proton Therapy (AcCEPT) for the treatment of lung tumours

External beam radiotherapy aims at delivering a curative dose to tumours while safeguarding surrounding healthy tissues. In the lung, this objective is challenged by the close presence of critical organs and breathing motion. Protons display appealing features to help reaching that goal: they show a reduced dose before a steep rise immediately followed by a sharp fall-off (the so-called “Bragg-peak”). However, the precision of the Bragg peak yields its major challenge: any uncertainty on its position may cause dramatic tumour/organs-at-risk under/over-exposure. This concerns particularly the tumours of the thorax because of the motion and the density variations. Treatment plans can be made robust to these uncertainties, inevitably with an increase of high-dose volumes. Treatment plans can also be continuously adapted to the actual anatomy, i.e. online adaptation. Unfortunately, online adaptation is workflow demanding and has a cost. This project aims at optimizing the trade-off between these two aspects.