Duerinckx A J, Macovski A
J Comput Assist Tomogr. 1978 Sep;2(4):481-7. doi: 10.1097/00004728-197809000-00020.
A series of artifacts in computed tomography (CT) images, consisting of streaks coming off edges and flares surrounding the object being scanned, is shown to be due to polychromaticity of the X-ray beam. These artifacts are seldom seen on conventional CT brain scans. They are helpful in understanding artifacts such as those seen around the petrous bone of the skull. Following this, a comparison is made between "single energy" and "dual energy" correction schemes for poly-artifacts. The theoretical assumptions underlying either method are analyzed, and the importance of these concepts in dual energy reconstructions is stressed. A new test phantom is suggested to evaluate different poly-correction schemes. All the simulated projection data in this study are noise free and are reconstructed using an industrial convolution-back projection technique. In addition, reconstructions are shown of the phantom using real data taken with and without a water bag path length compensator.
计算机断层扫描（CT）图像中的一系列伪影，由从边缘发出的条纹和围绕被扫描物体的光晕组成，已被证明是由于X射线束的多色性所致。这些伪影在传统的脑部CT扫描中很少见。它们有助于理解诸如在颅骨岩骨周围看到的伪影。在此之后，对多伪影的“单能量”和“双能量”校正方案进行了比较。分析了这两种方法的理论假设，并强调了这些概念在双能量重建中的重要性。建议使用一种新的测试模体来评估不同的多校正方案。本研究中的所有模拟投影数据均无噪声，并使用工业卷积反投影技术进行重建。此外，还展示了使用带有和不带有水袋路径长度补偿器的真实数据对模体进行的重建。
