| 摘要 |
PROBLEM TO BE SOLVED: To provide a multi-leaf collimator which can increase the precision of the contour formation of an irradiation image which is projected on an isocenter. SOLUTION: This multi-leaf collimator 10 is equipped with two stages of collimator blocks 11 and 12 which are constituted of a plurality of leaves 13 and 14 in the irradiation direction of an irradiation ray. In the multi-leaf collimator 10, the leaves constituting the collimator blocks in respective stages are constituted in a manner to be shifted by a specified pitch portion in the irradiation image of the applicable leaf which is projected on the isocenter by the irradiation ray. Thus, even when the irradiation ray such as a particle ray is not parallel but has a conical shape, the contour of an image which is actually irradiated can become more precise by making the irradiation images A1 and A2 projected on the isocenter 15 be shifted by a specified pitch. COPYRIGHT: (C)2006,JPO&NCIPI
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