Tomographic motion detection and correction directly in sinogram space
Tomographic motion detection and correction directly in sinogram space
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DOI：
10.1088/0031-9155/47/8/304
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发表时间：
2002-04-21
影响因子：
3.5
通讯作者：
Mackie, TR
中科院分区：
文献类型：
--
作者：
Lu, WG;Mackie, TR
病人的运动，尤其是呼吸运动，会在断层扫描图像中产生各种伪影，如模糊和条纹。在传输过程中，光束孔径的运动和器官解剖结构的变化的相互作用可以在调强放射治疗（IMRT）的整个领域中产生“热”和“冷”点。在断层成像和IMRT中，患者运动的检测和纠正是非常重要的。层析投影数据（sinogram）不仅编码了患者的解剖信息，而且还编码了扫描内的运动信息。在本文中。提出了一种在正弦图空间中直接检测和校正平面内呼吸运动的算法。呼吸运动建模为沿x和v方向的时变缩放。讨论了其对正弦图的影响。根据正弦图中一些节点的轨迹，确定扫描内运动。在正弦图空间中也实现了运动校正。采用滤波反投影（FBP）方法对运动校正后的正弦图进行重建。计算机仿真验证了运动检测和校正算法。由运动校正正弦图重建的图像消除了大部分伪影。该方法可用于CT和ECT的投影数据，也可用于断层治疗的给药修改和剂量重建。
Patient motion, especially respiratory motion, results in various artefacts such as blurring and streaks in tomographic images. The interplay of the movement of the beam aperture and variations of organ anatomy during delivery can create 'hot' and 'cold' spots throughout the field in intensity-modulated radiation therapy (IMRT). Detection and correction of patient motion is extremely important in tomographic imaging and IMRT. Tomographic projection data (sinogram) encode not only the patient anatomy information, but also the intra-scanning motion information. In this paper. we developed an algorithm to detect and correct the in-plane respiratory motion directly in sinogram space. The respiratory motion is modelled as time-varying scaling along the x and v directions. Its effects on the sinogram are discussed. Based on the traces of some nodal points in the sinogram, the intra-scanning motion is determined. The motion correction is also implemented in sinogram space. The motion-corrected sinogram is used for reconstruction by the filtered back-projection (FBP) method. Computer simulations validate the motion detection and correction algorithm. The reconstructed images from the motion-corrected sinogram eliminate the majority of the artefacts. The method could be applied to projection data used in CT and ECT, as well as in tomotherapy delivery modification and dose reconstruction.