PROBLEM TO BE SOLVED: To provide a depth-directional dose distribution measuring device capable of measuring the depth-directional dose distribution of particle beams even during the therapeutic radiation and to provide a particle therapy apparatus and a particle beam irradiation device.SOLUTION: An irradiation field forming device 20 includes a multiple ionization chamber type detector 30 mounted on the upstream side of a collimator member 44b of a block collimator 45. The detector 30 has a structure installed with a shielding body 33 for continuously or gradually changing the range of the beam, and a plurality of ionization chambers 37 on the subsequent stage thereof, and constitutes the depth-directional dose distribution measuring device 39 along with a signal processor 31. Part of the particle beam which reaches the interior of the radiation field forming device 20 passes through a beam passage 48 to be applied to a patient 60, and part of the residual particle beam enters the multiple ionization chamber type detector 30 to generate an electric charge in the interior of the ionization chambers 37. The signal processor 31 acquires the depth-directional dose distribution based on the amount of electric charge generated in the interior of each ionization chamber 37.COPYRIGHT: (C)2012,JPO&INPIT【課題】治療照射中においても粒子線の深さ方向線量分布を測定できる深さ方向線量分布測定装置、粒子線治療装置及び粒子線照射装置を提供する。【解決手段】照射野形成装置20はブロックコリメータ45のコリメータ部材44b上流側に取り付けられた複数電離箱型検出器30を備える。検出器30は、ビームの飛程を連続的又は段階的に変更する遮蔽体33とその後段に電離箱37を複数設置した構造を有し、信号処理装置31と共に深さ方向線量分布測定装置39を構成する。照射野形成装置20内に到達した粒子線の一部はビーム通路48を通過して患者60に照射され、残りの粒子線の一部が複数電離箱型検出器30に入射し、電離箱37内で電荷が発生する。個々の電離箱37内で発生した電荷量に基づいて、信号処理装置31で深さ方向線量分布が求められる。【選択図】図2
