Intraoperative radiotherapy or IORT consists in treating tissue suffering from neoplastic processes, made accessible by surgery, with an electron beam. After an experimental stage, in the sixties last century IORT cleared and set its election criteria and in the mid nineties, thanks to specific equipment enabling validation of new protocols, began to spread outside research environments. IORT has shown an evident capacity for the local control of cancer and can be applied to all solid tumours. The LIAC (Light Intraoperative Accelerator) is a machine created after carefully analysing limits set by what has to be done in a surgical environment; its prerogatives are the excellent possibility of being included in any operating theatre with no need to change existing structures. Its weight, extremely limited (400 kg), enables use on all floor types with no need to reinforce it and thanks to its size (200x80x180 cm) and manoeuvring capacity it can be transported in normal lifts carrying stretchers. The electronic beam energy (10 or 12 MeV) can satisfy almost any kind of therapy of a minimum complexity level to obtain use permits, while the amount of radiation produced means minimum time (50-100 seconds) needed to carry out treatment. The LIAC also has a supply stabilising system providing short and long term stability like conventional accelerators, and its electron beam means execution doses are precise like with completely conventional methods and instruments.