基于CT图像三维电子线放疗剂量的计算方法

A three-dimensional dose calculation method for electron beam irradiation based on CT images

背景:电子线放射治疗能有效治愈浅表和偏心的肿瘤,结合CT图像及三维剂量算法实现肿瘤的剂量精确定量,有利于肿瘤的局部控制率。目的:研究和实现一种基于CT图像的三维电子线放射治疗的计算方法。方法:采集临床鼻腔筛窦肿瘤患者的CT图像,通过VisualC++开发工具对CT图像进行DICOM解析,获取相关的数据,建立仿真人体矩阵信息,用以剂量模型的计算,包括斜入射校正和组织不均匀性校正。采用VTK技术重建出CT图像的矢状面和冠状面,根据剂量模型计算的剂量值,生成横断面、矢状面以及冠状面的等剂量分布曲线。结果与结论:根据面向对象的分析和设计理念,开发了交互式界面易操作、可视化程度高的治疗计划软件;给定靶区剂量计算得到加速器输出剂量;高剂量线能很好的适形靶区,并使正常组织和关键器官所受剂量很小,从而得到保护。实现电子线放射治疗患者体内剂量的可视化,直观显示剂量分布,对提高患者的放射治疗质量和精确放疗的后续研究具有指导意义。

BACKGROUND： Electron beam irradiation can effectively cure superficial and eccentric tumors. Combined with CT images and three-dimensional dose algorithm, we can also realize the precise quantification of tumor dose using electron beam irradiation, which is more advantageous to tumor local controlling. OBJECTIVE： To study and implement a three-dimensional electron beam dose calculation method based on CT images. METHODS： The CT images of patients with nasal cavity and ethmoid sinus cancer were collected. Microsoft Visual C＋＋ was used to parse CT images for related information, and then the human body emulational matrix was built for the dose model calculation, including oblique incidence correction and tissue inhomogeneity correction. The sagittal and coronal CT images in the three-dimensional display were reconstructed using VTK technique. The dose distribution curves displayed on cross-sectional, sagittal and coronal images were drawn by the dose distribution calculation methods. RESULTS AND CONCLUSION： According to the object-oriented analysis and design concept, we developed a high-visualized treatment planning software with interactive interface that is easy to operate. Besides, it could calculate accelerator output dose based on given target area dose. High doses line could be a very good conformal target area, and it could minimize the dose on the normal tissues and key organs, thereby protecting the tissues and organs. This planning software we developed realized the dose visualization in patients undergoing electron beam radiation therapy, and visually displayed the dose distribution, which is of significance for further improving the curative effects of radiation treatment and subsequent research of accurate radiotherapy.