Reportage in the National Oncology Particle Therapy Centre in Milan, Italy (The CNAO - Centro Nazionale di Adroterapia Oncologica). Particle therapy is a state-of-the-art technique used to treat cancer. It consists of using hadrons, protons (proton therapy) and cabon ions (carbon-ion treatment) to irradiate tumours. It has two therapeutic purposes, a high ballistic accuracy which allows healthy tissue surrounding the tumour to be spared, and a greater efficiency at treating certain cancers. The CNAO is the only centre to own carbon-ion treatment technology in Europe. An x-ray is carried out to check that the patient is in exactly the right position.