PROBLEM TO BE SOLVED: To propose a breast shape change prediction method, breast shape change prediction system, and breast shape change prediction program for predicting shape change of a breast caused by extirpation of a lesion.SOLUTION: A breast shape change prediction method of the present invention includes: a step of identifying a breast model 11 and lesion model 12 a step of setting motion points m1 to m11 on an outer surface of the breast model 11 and setting fixed points f1, f2 on a boundary between a breast part 11a and a chest part 11b a step of calculating fixed vectors V1, V2 connecting a centroid 12a of the lesion model 12 with the fixed points f1, f2, respectively, as well as calculating a movement direction vector V3 a step of setting, as a working point e, an intersection between a movement direction line T and the lesion model 12 a step of calculating the entire length of a tension line as well as calculating a partial length of the tension line and a step of moving the motion points m5 to m11 along tension lines L5 to L11 so that each motion depends on a ratio of a partial length of a corresponding tension line to the entire length of the tension line.SELECTED DRAWING: Figure 10COPYRIGHT: (C)2018,JPO&INPIT【課題】患部摘出に伴う乳房の形状変化を予測するための乳房形状変化予測方法、乳房形状変化予測システム、及び乳房形状変化予測プログラムを提案する。【解決手段】本発明の乳房形状変化予測方法は、乳房モデル11と患部モデル12とを特定するステップと、乳房モデル11の外表面に動作点m1~m11を設定し乳房部分11aと胸部分11bとの境界に固定点f1、f2を設定するステップと、患部モデル12の重心12aと固定点f1、f2のそれぞれとを結ぶ固定ベクトルV1、V2を算出するとともに移動方向ベクトルV3を算出するステップと、移動方向線Tと患部モデル12の境界との交点を作用点eと設定するステップと、張力線全長を算出するとともに、張力線部分長を算出するステップと、張力線全長に対する張力線部分長の割合に応じて動作点m5~m11を張力線L5~L11に沿って移動させるステップとを備える。【選択図】図10