PARTICLE BEAM THERAPY APPARATUS AND THERAPY PLANNING APPARATUS AND CHARGED PARTICLE BEAM IRRADIATION METHOD

摘要

PROBLEM TO BE SOLVED: To provide a charged particle beam irradiation method uniformizing a dose applied to an affected region by a small number of beam irradiation spots. SOLUTION: The affected region is split into layers, and beam irradiation spots are installed in the form of a triangle within a two-dimensional plane surface of a certain layer Si. Beam irradiation spots of a preceding layer Si-1 are set in the center of triangular beam irradiation spots set in the certain layer Si among the beam irradiation spots of the layer Si, whereby an affected site area can be irradiated flatly by a small number of beam irradiation spots.