A design of a compact gantry for proton therapy with 2D-scanning

A compact gantry (3 m radius) for proton therapy in which a so-called ''pen cil" beam scans a 30 x 30 cm(2) surface, has been designed. The advantages of this gantry are its small size and the bet that no mechanical movements of magnets or patient couch are necessary to accomplish the two-dimensional scanning. In our design the pencil beam scanning is performed by two indep endently working scanning magnets. A compact system has been achieved by in tegration of the beam scanning into the ion optical design of the gantry. T he large deflections of the pencil beam from the optic axis of the gentry h ave been treated correctly by the ion optics Code COSY. The ion optical des ign of the gantry and the use of COSY for the study of the action of the sc anning magnets are discussed. (C) 1999 Elsevier Science B.V. All rights res erved.