System for ion acceleration for medical purposes comprising a conventional or superconducting cyclotron, a radiofrequency linear accelerator (Linac), a Medium Energy Beam Transport line (MEBT) connected, at the low energy side, to the exit of the cyclotron, and at the other side, to the entrance of the linear radiofrequency accelerator, as well as a High Energy Beam Transport line (HEBT) connected at high energy side to the radiofrequency linear accelerator exit and at the other end, to a system for the dose distribution to the patient.The high frequency of operation of the Linac allows for a reduced consumption and a remarkable compactness facilitating its installation in hospital structures. The use of a modular LINAC allows varying in active way the energy and the current of the therapeutic beam, having a small emittance and a time structure adapted to the dose distribution based on the technique known as the “spot scanning”.