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对于旋转放射治疗设备,其等中心点位置对治疗精度存在重要影响。针对设备负载引起的机械结构变形对等中心误差的影响,提出了一种确定旋转放疗设备等中心点的平均矢量算法。以等中心点位置为优化变量,通过限定等中心点与不同位置射线向量的最大距离建立约束条件,以满足约束条件的等中心点与射线向量的平均距离为目标函数,得到最优等中心点位置和等中心包络线。实例分析验证了平均矢量算法的正确性和有效性。平均矢量法与矢量法得出的等中心包络线半径均为0.311mm,比节点法降低约15.5%;平均矢量法给出的等中心点距各射线向量的平均距离为0.206mm,比矢量法降低约11.2%,比节点法降低约28%。
For rotational radiotherapy equipment, the location of its isocenters has an important effect on the accuracy of the treatment. Aiming at the influence of equipment load on the center error of mechanical structure deformation, an average vector algorithm for determining center points of rotating radiotherapy equipment is proposed. Taking the isocenter position as the optimization variable, the constraint condition is established by defining the maximum distance between the isocenter and the ray vector at different positions, and the average distance between the isocenter and the ray vector that satisfies the constraint condition is taken as the objective function to obtain the optimal isocentric position And the center envelope. The example analysis verifies the correctness and validity of the average vector algorithm. The average radius of the isocenter obtained by the average vector method and the vector method is 0.311 mm, which is 15.5% less than that of the nodal method. The mean distance from the isocenter to the ray vectors is 0.206 mm, Method reduced about 11.2%, about 28% lower than the node method.