基于CT图像的三维后装腔内治疗计划系统的研制

Design of a 3D Afterloading Brachytherapy Simulation System Based on CT Images

目的:开发一种新的适合于临床应用的基于CT图像的三维后装腔内治疗计划系统。方法:对插三个硬管的仿真人体盆腔体模和插二个软管的鼻咽癌患者进行CT扫描,以Microsoft Visual C++为开发工具,对CT图像进行dicom解析,提取有用的信息,然后重建施源管的三维坐标,并给出驻点的三维坐标,接着程序实现源外剂量分布计算方法和剂量优化算法,最后在CT层面生成等剂量线,采用VTK技术进行三维显示。结果:本系统能依临床预设的参考剂量点,逆向计算驻点的驻留时间,生成符合临床要求的等剂量面,三维显示等剂量体与正常组织的空间关系。结论:为临床医生提供一种具有三维剂量分布显示的人机交互布源的基于CT图像的三维后装腔内治疗计划系统,克服目前国内普遍使用的基于X线片的二维后装计划系统的不足。目前本系统正临床测试,效果良好。

Objective To design a new afterloading brachytherapy simulation system based on CT images. Methods This paper mainly focuses on the anthropomorphic pelvic phantom spiled by three pipelines and the nasopharyngeal carcinoma spiled by two pipelines. Microsoft Visual C＋＋ was used to parse CT images for some information, then to reconstruct pipelines in the body of phantom or the patient and to give the three-dimensional coordinate of dwelling points. The dose distribution displayed on CT images was processed by the dose distribution calculation methods near single afterloading source and the dose optimization methods. VTK technology was used in the 3D display in the system. Results According to the reference points applied by doctors, the system can calculate reversely the dwelling time of dwelling points in pipelines and get satisfying dose distribution on CT images. Besides, it can reflect the 3D relationship between the dose volume and the normal tissues. Conclusions This system overcomes some deficiencies of 2D afterloading brachytherapy simulation system based on X-ray films which are used widely in China. It supplies 3D display of dose distribution for clinical doctors. At present, the system is being tested in clinics.