基于C型臂的Tomosynthesis快速重建方法

Fast reconstruction method based on C-arm tomosynthesis

传统的层析X射线摄影合成(Tomosynthesis)算法不适合对C型臂X射线投影进行切片重建.提出了一种改进的Tomosynthesis算法CTS(C-arm based Tomosynthesis),依据C型臂成像原理,将不同角度的X射线投影按其映射关系在三维空间内旋转-叠加来重建切片.该算法可以对等中心C型臂连续采集的一组有限角度X射线投影进行切片重建.通过计算机模拟空心球和空心圆柱模型的C型臂X射线投影,用该算法对其二维投影进行切片重建,并利用重建结果分析了CTS算法的重建精度以及抗噪声干扰能力.最后给出了将CTS算法推广到可以对非等中心C型臂进行切片重建的步骤.CTS为基于C型臂的术中三维成像提供了一种参考方法.

As the traditional tomosynthesis is not appropriate for C-arm based slice reconstruction, a modified tomosynthesis method, CTS（ C-arm based tomosynthesis） , was proposed. CTS method rotates and overlays all the X-ray projections in 3-D space according to the mapping matrices of different angles, which can get from the geometry of the C-arm. This method can be used for the limited-angle cone-beam reconstruction, which is very suitable for isocentric C-arm imaging. The algorithm simulations with projections of a hollow sphere and two hollow-cylinder models show good image quality and demonstrate CTS has high precision. The reconstruction from projections with noise was also conducted. The results show that CTS is noise-insensitive, which validates the feasibility of the method for C-arm 3-D imaging. Finally, the process that makes CTS method adapt to the non-isocentric C-arm was proposed.