PROBLEM TO BE SOLVED: To solve a problem based on excessive irradiation in IMRT.SOLUTION: A therapeutic device 51 with particle beam comprises a columnar irradiation field generating device 4 which expands Bragg peak of a charged particle beam 1 and generates a columnar irradiation field. The columnar irradiation field generating device 4 comprises: a pair of upstream side deflection electromagnets 5 and 6 two range shifters 9a and 9b two ridge filters 19a and 19b which are disposed at respective downstream side and having different thickness distribution and a pair of downstream side deflection electromagnets 7 and 8. A therapy planning device preparing a therapy plan in the therapeutic device 51 comprises: an irradiation field arranging part which arranges a columnar irradiation field 44 according to distal configuration of an irradiation target 40 and inwardly paves the irradiation target 40 with columnar irradiation fields 45 having a width in SOBP different from that of the columnar irradiation field 44 and an optimization calculation part adjusting arrangement of the columnar irradiation fields 44 and 45 so that irradiation dose to the irradiation target 40 is within a predetermined range.COPYRIGHT: (C)2015,JPO&INPIT【課題】IMRTの過照射問題を解決することを目的としたものである。【解決手段】荷電粒子ビーム1のブラッグピークを拡大し、柱状の照射野を生成する柱状照射野生成装置4を備えた粒子線治療装置51であって、柱状照射野生成装置4は、上流側偏向電磁石対5、6と、2つのレンジシフタ9a、9bと、それぞれの下流側に配置され、異なる厚さ分布を有する2つのリッジフィルタ19a、19bと、下流側偏向電磁石対7、8とを備え、当該治療装置51の治療計画を作成する治療計画装置は、照射対象40のディスタル形状に応じて、柱状照射野44を配置するとともに、照射対象40の内側に柱状照射野44と異なるSOBPの幅を有する柱状照射野45を敷き詰めて配置する照射野配置部と、照射対象40への照射線量が所定の範囲に入るように柱状照射野44、45の配置を調整する最適化計算部とを有する。【選択図】図9
