PROBLEM TO BE SOLVED: To provide a raditherapeutic system or the like capable of reducing the measurement errors of the dose of a therapeutic beam caused by attenuation of scattering radiation in a subject itself and measuring scattering radiation source distribution having high quantitative property by reconfiguring a scattering radiation source using a high-speed and accurate attenuation correction method.SOLUTION: In the radiotherapeutic system of a type for monitoring the dose of the therapeutic radiation by the scattering radiation, in order to correct the attenuation by the passing of the scattering radiation through the body, a plane where the scattering radiation source is present is determined, a passing path between the scattering radiation source and a detector is determined on the basis of CT images, the degree of the attenuation is estimated and influence by the attenuation included in the detected result of the scattering radiation is corrected.COPYRIGHT: (C)2009,JPO&INPIT【課題】 高速で正確な減弱補正方法を用いて散乱源の再構成を行うことで、散乱線が被検体自体で減弱されるために生じる治療線の線量の測定誤差を低減し、定量性の高い散乱源分布を計測することができる放射線治療システム等を提供すること。【解決手段】 治療放射線の線量を散乱線によりモニタする方式の放射線治療システムにおいて、散乱線が体内を通過することによる減弱を補正するため、散乱源の存在する平面を決定し、散乱源から検出器の間の通過パスをCT画像を元に決定し、源弱の程度を推定し散乱線の検出結果に含まれる源弱による影響を補正する。【選択図】 図9
