MULTI-LEAF COLLIMATOR, PARTICLE BEAM THERAPY SYSTEM, AND TREATMENT PLANNING APPARATUS

摘要

The objective thereof is to obtain a multi-leaf collimator and a particle beam therapy system in which a high-contrast irradiation field can be formed without undergoing the effect of a penumbra. There are provided a leaf row (5_C) in which a plurality of leaf plates (5_L) are arranged in the thickness direction of the row (5_C) in such a way that the respective one end faces (E_L) of the leaf plates (5_L) are trued up and a leaf plate drive mechanism (5_D) that drives each of the plurality of leaf plates (5_L) in such a way that the one end face (E_L) approaches or departs from a beam axis (X_B). In each of the leaf plates (5_L), a facing side (PL) facing a leaf plate that is adjacent to that leaf plate in the thickness direction is formed of a plane (P_sa) including a first axis (A_sa) on the beam axis (X_B); the leaf plate drive mechanism (5_D) drives the leaf plate (5_L) along a circumferential orbit (O_L) around the second axis (A_sb), on the beam axis (X_B), that is perpendicular to the beam axis (X_B) and the first axis (A_sa).