Beam-optics study of the gantry beam delivery system for light-ion cancer therapy

Beams of light ions (Z = 1–8) have favourable physical and biological properties for their use in radiotherapy. Their advantages are best pronounced if the beam is delivered in a tumour-shape conformed way. The highest degree of conformity could be achieved by combination of a rotating gantry with an active pencil-beam scanning. Ion-optics considerations on such a gantry beam delivery system for light-ion cancer therapy are presented. A low-angle magnetic beam scanning in two perpendicular directions is included in the beam transport system of the gantry. The optical properties of the beam transport system are discussed.