一种新的基于平面检测器的锥形束体积重建算法

由于锥形束体积重建算法具有较高的获取投影数据的速度、较大的 X射线利用率及能保持重建物体的空间和密度各向同性等方面的优点 ,因而引起了人们的广泛关注 .针对锥顶轨迹为单圆的锥形束体积重建问题 ,提出了一种基于平面检测器的 T- FDK算法 (简称 FT- FDK算法 ) .该算法首先将锥形束投影数据重排为倾斜平行投影数据 ,然后再经过加权滤波和反投影重建来得到待测物体的三维结构 .实验结果表明 ,该算法不仅与传统的 FDK算法有相同的计算复杂度 ,且重建图象的质量有了明显的提高 ,因而该算法在医学成像和无损探伤等领域具有重要的实用价值 .

A New Cone-beam Reconstruction Algorithm Based on Planar Detector

Cone-beam reconstruction, which is also called volumetric reconstruction, has been one of the central research problems in medical imaging. Compared with traditional 3D reconstruction, it has several advantages, such as faster scanning, better dose usage and the isotropy of the spatial resolution and density resolution in 3D reconstruction object. Based on the idea of Grass's T-FDK algorithm, a new volumetric reconstruction algorithm named FT-FDK, was presented in this paper. The X-ray projection data were collected on a planar detector instead of a cylinder detector, which was quite different from Grass's algorithm. The 2D projects were obtained along a single circular source trajectory. Unlike traditional FDK algorithm, there were three steps in this new algorithm. The first step was that the projection data should be rebinned to oblique parallel projection data. Then, the rebinned oblique parallel projection data should be pre-weighting filtered. And the last step was that filtered projection data should be backprojected to the final 3D reconstructed image data. Theory and experimental results indicated that this algorithm had the same computational complexity as traditional FDK algorithm and the image quality was improved in the reconstruction. The results suggest that this algorithm can be used widely in applications of medical imaging and nondestructive testing.