基于图形处理器的锥束CT快速迭代重建算法

A Rapid Cone-Beam CT Iterative Algorithm Based on Graphics Processing Unit

提出了一种基于图形处理器实现的锥束CT图像迭代重建算法.该算法将三维纹理作为被重建物体的离散模型,基于射线投射方法实现了锥束CT的正投影计算;通过反向逐层映射到三维纹理实现了反投影计算;采用多纹理融合等技术完成了图像校正和投影校正.与经典的TMA-SART算法比较,作者算法运算速度快,占用显存少,支持全浮点精度运算,且易于在算法中添加先验知识和约束条件.通过对Shepp-Logan模型的图像迭代重建实验,验证了该算法的优势.

A graphics processing unit （GPU） based cone-beam CT iteration algorithm is proposed. This algorithm takes 3D texture as the discrete model of reconstructed object. It includes several base modules： the forward-projection based on ray casting, the backwardprojection by backward mapping projections to each slice of object 3D texture, and the image correction and projection correction by multi-texture blending. Compared with classical TMASART algorithm, the proposed algorithm has a faster reconstruction speed in full floating point precision, requires less video memory, and is easier to incorporate prior knowledge and constraints into its framework. These advantages of the algorithm are verified by the experiment of the 3D image iterative reconstruction of Shepp-Logan phantom.