Since long time therapies based on light-particle accelerators are used to help in cancer treatment. Photons (radiotherapy) are used in almost any large hospital in the world. Nevertheless, there are other particles that can be used, in particular protons and ions. I will discuss their advantages with respect to standard therapy in specific forms of tumours and I will concentrate on hadrontherapy, the one that makes use of carbon ions. I will describe a complex that has been built in Italy with substantial help from my institute (Nuclear Physics National Institute –INFN) in Pavia, which has started to cure patients not long ago.