The system comprises a patient support 110, a radiation beam generator mounted on a gantry (128, fig 2), the gantry being moveable so as to rotate the radiation beam generator around the patient support, and a control system 200, 300 including a real time control system 216 mounted on the gantry and configured to provide real-time control signals 221 to the patient support, 220 to the radiation beam generator, and 218 to the gantry. The system may comprise an off-gantry control system 300 configured to exchange control signals with the real-time system mounted on the gantry. The connection may be wireless 210 or may comprise a fibre-optic link 310 between the off-gantry control system and the patient support. Providing the control system on the gantry may allow the system to be operated while the gantry is rotated through more than 360 degrees.
