1. An ion therapy machine comprising: an ion source for producing an ion beam traveling along an axis; means for varying a lateral width of the ion beam perpendicular to the axis as a function of a control signal; means for varying an axial extent of the beams when steered to portions of the patient according to a control signal; means for steering a center of the ion beam to different portions of a patient according in both lateral and axial dimensions to a control signal; and a beam controller executing a stored radiation plan to communicate control signals to the means for varying a lateral width, the means for varying an axial extent and the means for steering the ion beam, to provide a radiation treatment to the patient by applying ion beams of different widths to different portions of the patient.