A method for deconvolution of integrated electronic portal images to obtain incident fluence for dose reconstruction
A method for deconvolution of integrated electronic portal images to obtain incident fluence for dose reconstruction
复制标题
DOI：
10.1120/jacmp.2026.25359
复制
发表时间：
2005-01-01
影响因子：
2.1
通讯作者：
Holmes, Timothy
中科院分区：
文献类型：
--
作者：
Renner, Wendel Dean;Norton, Kevin;Holmes, Timothy
本文研究了一种将集成电子射野成像设备（EPID）图像转换为注量以重建体模剂量的方法。最终，目标是开发一种方法来重建患者的剂量。通过反卷积核的空间滤波将EPID图像转换为入射强度通量。内核使用从EPID的点扩散函数的蒙特卡罗计算导出的一般数学形式。使用下坡搜索算法拟合去卷积核，该算法最小化重建剂量与水中测量剂量之间的差异。通过EPID校准程序去除的光束轮廓“喇叭”通过使用测量的空气离轴比直接相乘恢复到所得图像。将拟合的核应用于EPID图像提供了该光束的入射通量。然后将该射束通量输入到独立的剂量计算算法中，用于体模或患者剂量重建。计算体模剂量时，在一个标准差下，准确度为d（max）剂量的2.0%。该方法具有通用性，可适用于任何具有积分模式的EPID。我们证明了应用的拟合核在两个临床调强放射治疗的情况下。
A method to convert integrated electronic portal imaging device (EPID) images to fluence for the purpose of reconstructing the dose to a phantom is investigated here for simple open fields. Ultimately, the goal is to develop a method to reconstruct the dose to patients. The EPID images are transformed into incident intensity fluence by spatial filtering with a deconvolution kernel. The kernel uses a general mathematical form derived from a Monte Carlo calculation of the point spread function of an EPID. The deconvolution kernel is fitted using a downhill search algorithm that minimizes the difference between the reconstructed dose and the dose measured in water. The beam profile "horns" that are removed by the EPID calibration procedure are restored to the resulting images by direct multiplication using the measured in-air off-axis ratio. Applying the fitted kernel to an EPID image provides the incident fluence for that beam. This beam fluence is then entered into an independent dose calculation algorithm for phantom or patient dose reconstruction. The phantom dose was computed to an accuracy of 2.0% of the d(max) dose at one standard deviation. The method is general and can possibly be applied to any EPID equipped with an integration mode. We demonstrate the application of the fitted kernel in two clinical IMRT cases.