Reducing metal artifacts in cone-beam CT images by preprocessing projection data
Reducing metal artifacts in cone-beam CT images by preprocessing projection data
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DOI：
10.1016/j.ijrobp.2006.09.045
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发表时间：
2007-03-01
影响因子：
7
通讯作者：
Dong, Lei
中科院分区：
文献类型：
--
作者：
Zhang, Yongbin;Zhang, Lifei;Dong, Lei
目的：金属植入物引起的计算机断层扫描（CT）条纹伪影仍然是图像数据自动处理的一个挑战。在锥形束CT（CBCT）中，软组织区域中的金属伪影的影响被放大，因为CBCT图像中的软组织对比度通常较低。本研究的目标是开发一种有效的离线处理技术，以尽量减少effect.Methods和Materials：CBCT系统的几何校准线索被用来跟踪的投影视图中遇到的对象的位置。对象的三维（3D）表示可以仅从两个用户选择的视角建立。阴影区域在其他视图中的位置可以通过投影对象的3D坐标来跟踪。使用自动图像分割，然后使用拉普拉斯扩散方法将金属对象内部的像素替换为边界像素。然后使用修改后的投影数据重建新的CBCT图像。该程序进行了测试，在幻影，前列腺癌患者植入金标记物和金属假体，和头部和颈部的患者与牙科汞合金的牙齿。结果：幻影和患者的研究表明，该程序是能够尽量减少金属伪影。在金属物体附近或远离金属物体处的软组织可见性得到改善。处理时间为1-2 s/投影。结论：我们已经实现了一个有效的金属伪影抑制算法，以提高CBCT图像的质量。(c)2007年爱思唯尔公司
Purpose: Computed tomography (CT) streak artifacts caused by metallic implants remain a challenge for the automatic processing of image data. The impact of metal artifacts in the soft-tissue region is magnified in cone-beam CT (CBCT), because the soft-tissue contrast is usually lower in CBCT images. The goal of this study was to develop an effective offline processing technique to minimize the effect.Methods and Materials: The geometry calibration cue of the CBCT system was used to track the position of the met object in projection views. The three-dimensional (3D) representation of the object can be established from only two user-selected viewing angles. The position of the shadowed region in other views can be tracked by projecting the 3D coordinates of the object. Automatic image segmentation was used followed by a Laplacian diffusion method to replace the pixels inside the metal object with the boundary pixels. The modified projection data were then used to reconstruct a new CBCT image. The procedure was tested in phantoms, prostate cancer patients with implanted gold markers and metal prosthesis, and a head-and-neck patient with dental amalgam in the teeth.Results: Both phantom and patient studies demonstrated that the procedure was able to minimize the metal artifacts. Soft-tissue visibility was improved near or away from the metal object. The processing time was 1-2 s per projection.Conclusion: We have implemented an effective metal artifact-suppressing algorithm to improve the quality of CBCT images. (c) 2007 Elsevier Inc.