| 摘要 |
<p>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 ).</p> |
