This invention provides a corpuscular beam scanning irradiation system which includes a computer for determining the sequential order of irradiation of the corpuscular beam to the tumor region of a patient, and corpuscular beam irradiation apparatus for irradiating the tumor region of the patient with the corpuscular beam according to the determined sequential order of irradiation of the corpuscular beam. The computer selects from a plurality of irradiation spots arranged in the tumor region, a combination of a pair of all irradiation spots that can be presumed, and performs the steps of judging whether or not is there a crossing point on the moving path of the corpuscular beam with the region of an organ when the corpuscular beam passes between two irradiation spots that constitutes the selected pair, the step of determining a penalty matrix which represents if there is a crossing point in the moving path with the region of organ with matrix elements based on the result of the judgement, and the step of evaluating an evaluation function of the moving path based on a mostly optimized algorithm, and the step of confirming the sequential order of irradiation of the corpuscular beam based on the most optimal solution of the evaluation function obtained from the above evaluation of the evaluation function of the moving path.本發明之粒子射線掃描照射系統係包括:計算機,用以確定對患者的腫瘤區域之粒子射線的照射順序;以及粒子射線照射裝置,依據所確定之粒子射線的照射順序而將粒子射線照射至患者的腫瘤區域。計算機係執行下列步驟:從配置於腫瘤區域之複數個照射點中選擇能考量到之全部的照射點的配對之組合,並判斷當粒子射線移動於構成所選擇之配對之二個照射點之間時,是否在粒子射線的移動路徑有與臟器區域之交差點之步驟;依據該判斷結果,來決定以矩陣係數表現是否在移動路徑有與臟器區域之交差點之損失矩陣之步驟;以及依據最佳化演算法來評估移動路徑的評估函數,並依據由該評估所得到之評估函數的最佳化解來確定粒子射線的照射順序之步驟。21‧‧‧腫瘤目標區域設定手段22‧‧‧重要臟器區域設定手段23‧‧‧照射位置群設定手段24‧‧‧照射順序最佳化手段25‧‧‧粒子射線治療照射控制手段26‧‧‧粒子射線照射裝置
