XN-1型放射治疗CT定位系统的研制与应用

Design and application of XN-1 CT simulation system

目的 对自行研制的XN 1型放射治疗CT定位系统的使用方法和功能进行介绍与验证。方法 本系统由定位框架和定位软件组成 ,定位框架以往已经报道。软件为在Windows平台上应用OpenGL三维图形工具自主研发的软件系统。本系统能够建立基于定位框架的三维坐标系 ,对身体外轮廓、肿瘤及其周围重要器官进行三维重建 ,通过射束方向视图 (beam’seyeview ,BEV)功能进行模拟 ,确定出靶中心点的空间坐标、各照射野的方向、大小和源瘤距等放疗参数 ,从而实现精确模拟定位。对模拟靶进行了验证 ,并对食管癌和脑肿瘤病例进行了比较。结果 本系统确定的模拟靶之中心点坐标、照射野的方向和大小等 ,经与模拟定位片对比验证 ,证明达到精确定位要求。对临床病例的定位结果也与模拟定位机方法一致。结论 本系统能够对全身各部位肿瘤进行精确的CT立体定位 ,能够提供常规放疗所需各项定位参数。具有精确度高、显示直观、稳定可靠等优点 ,适合国情 ,具有重要推广应用价值。

Objective To introduce the self-designed XN-1 CT simulation system and its application in radiotherapy. Methods The system was consisted of localization frame and simulation software. The frame was reported in detail previously. The software was designed based on Windows system with 3D tool OpenGL. During the process of simulation, CT images were scanned into the computer and the stereotactic coordinate system was created on the basis of the markers on the frame. The contours of tumor and other structures were defined and outlined respectively. They were reconstructed and displayed in 3D mode. The isocenter of target, the angles and sizes of radiation fields were setup and optimized with the help of Beam's Eye View so that the CT simulation could be successfully finished. The function and accuracy of the system were verified with a Philips MC-P50 simulator to a phantom target. For patients with brain tumor and esophageal carcinoma were also verified with the two simulation modalities. Results The simulation parameters obtained by the CT simulation system were coincident with those with the simulator. For the clinical cases, the results were also accordant with those by the stimulator. Conclusion The XN-1 CT simulation system has strong simulation function and it can meet nearly all the needs of simulation for conventional radiotherapy. It has the advantages such as high accuracy, friendly interface, easy operation, and low cost.