精确放射治疗计划系统中快速三维重建方法的研究与应用

在放射治疗计划系统中,为了精确地照射靶区避开危及器官,有必要对勾画的二维轮廓信息进行三维重建。现有的三维重建方法难以在拟合真实度和实时性上同时满足临床需求。通过对等值面提取算法进行改进,本文设计了一种快速三维重建流程,并基于可视化开发包(VTK)加以实现。多套来自真实病人影像数据的测试结果表明,快速三维重建法得到的面模型表面光滑,有效避免了"阶梯"效应;面片和顶点数目大幅度削减;与一般的等值面提取算法比较绘制时间大大减少。在保证真实拟合原始解剖结构的前提下,文中的方法改善了重建效果、提高了绘制速度,不仅可应用在精确三维放射治疗计划系统中,也可扩展应用在其他领域。

Research and application of a fast 3D-reconstruction method in accurate radiotherapy treatment planning system

In radiotherapy treatment planning, in order to delivery of a high dose to the tumor accurately while maintaining an acceptably low dose to the normal tissues, particularly those adjacent to the target, it is necessary to reconstruct the three dimensional anatomical structure from planar contour information. The existing methods could not satisfy the clinical demand in terms of the speed and accuracy. By improving the isosurface extraction algorithm, we designed a fast 3D-reconstruction algorithm pipeline implemented by Visualization Tool Kit (VTK). A serial of test results from real patient image dataset show that this method could reconstruct the surface smoothly and evade the "ladder effect" effectively. The number of points and triangles had been reduced in great extent. The rendering time had been decreased from 8 seconds to less than 3 seconds by comparing with standard iso-extraction algorithm. On the premise of preserving the original anatomical structure, this method improved the reconstruction effect, accelerated the rendering speed and it would be applied to not only accurate radiotherapy treatment planning system but also other fields that need 3D reconstruction.