【摘要】 充分考虑调强放疗计划系统产生的计划剂量数据中存在较多梯度边缘点的特点,提出了一种基于梯度特征的调强放疗计划剂量插值算法(TDAGI)。算法首先改进了传统Canny边缘探测方法,并根据计划剂量数据平面的梯度信息来获取该平面上各梯度边缘点和非梯度边缘点;对梯度边缘点追踪梯度剖面并计算其所对应的锐度,对非梯度边缘点计算自定义的偏离系数。使用锐度和偏离系数,通过TDAGI所构造的分布函数得到以该数据平面上每一点为双三次插值中心点时对应的双三次插值核的系数,对每一个待插值点进行特定的双三次插值,从而得到每一个待插值点的计划剂量数据。结果表明TDAGI与传统双三次插值算法以及目前治疗计划系统中广为使用的双线性插值算法相比,在减小误差的同时,具有梯度保持方面的优势,因此TDAGI对于调强放疗计划剂量插值有一定的实际应用意义。更多还原

【Abstract】 The dose data produced by treatment plan system(TPS)in intensity-modulated radiation therapy(IMRT)has many gradient edge points.Considering this feature we proposed a new interpolation algorithm called treatment plan dose interpolation algorithm based on gradient feature in intensity-modulated radiation therapy(TDAGI),which improves the Canny algorithm to detect the gradient edge points and non-edge points by using the gradient information in the dose data plane.For each gradient edge point,the corresponding gradient profile was traced and the profile’s sharpness was calculated,and for each non-edge point,the dispersion was calculated.With the sharpness or dispersion,the kernel coefficients of bi-cubic interpolation can be obtained and can be used as the central point to complete the bi-cubic interpolation calculation.Compared with bi-cubic interpolation and bilinear interpolation,the TDAGI algorithm is more accurate.Furthermore,the TDAGI algorithm has the advantage of gradient keeping.Therefore,TDAGI can be used as an alternative method in the dose interpolation of TPS in IMRT.更多还原