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1. 发明授权

US07881424B2 Method for calibrating dual-energy CT system and method of image reconstruction 有权
标题翻译：校准双能CT系统的方法和图像重建方法
公开(公告)号：US07881424B2
公开(公告)日：2011-02-01
申请号：US12075463
申请日：2008-03-11
申请人： Li Zhang , Zhiqiang Chen , Gnowei Zhang , Jianping Cheng , Yuanjing Li , Yinong Liu , Yuxiang Xing , Ziran Zhao , Yongshun Xiao
发明人： Li Zhang , Zhiqiang Chen , Gnowei Zhang , Jianping Cheng , Yuanjing Li , Yinong Liu , Yuxiang Xing , Ziran Zhao , Yongshun Xiao
IPC分类号： G01N23/00
CPC分类号： G01T7/005 , G01T1/1648
摘要： A method for calibrating a dual-energy CT system and an image reconstruction method are disclosed to calculate images of atomic number and density of a scanned object as well as its attenuation coefficient images at any energy level. The present invention removes the effect from a cupping artifact due to X-ray beam hardening. The method for calibrating a dual-energy CT system is provided comprising steps of selecting at least two different materials, detecting penetrative rays from dual-energy rays penetrating said at least two different materials under different combinations of thickness to acquire projection values, and creating a lookup table in a form of correspondence between said different combinations of thickness and said projection values. The image reconstruction method is provided comprising steps of scanning an object with dual-energy rays to acquire dual-energy projection values, calculating projection values of base material coefficients corresponding to said dual-energy projection values based on a pre-created lookup table, and reconstructing an image of base material coefficient distribution based on said projection values of base material coefficients. In this way, images of atomic number and density of an object as well as its attenuation coefficient images can be calculated from the images of the distribution of base material coefficients. Compared with the prior art technique, the method proposed in the present invention has advantages of simple calibration procedure, high calculation precision and invulnerability to X-ray beam hardening.
摘要翻译：公开了用于校准双能量CT系统和图像重建方法的方法，以计算被扫描物体的原子序数和密度以及其在任何能级的衰减系数图像的图像。本发明消除了由于X射线束硬化引起的拔罐伪影的影响。提供了一种用于校准双能量CT系统的方法，包括以下步骤：选择至少两种不同的材料，从不同厚度的组合穿透所述至少两种不同材料的双能量射线检测穿透射线，以获得投影值，以所述不同的厚度组合和所述投影值之间的对应形式的查找表。提供了图像重建方法，包括以下步骤：用双能量射线扫描物体以获取双能量投影值，基于预先创建的查找表计算与所述双能量投影值相对应的基材系数的投影值，以及基于所述基材系数的投影值重构基材系数分布的图像。以这种方式，可以从基材系数分布的图像中计算出物体的原子数和密度以及衰减系数图像的图像。与现有技术相比，本发明提出的方法具有校准过程简单，计算精度高，X射线束硬化无效的优点。

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