Laboratory of Image Science and Technology, School of Computer Science and Engineering, Southeast University, Nanjing, People's Republic of China.
Beijing Engineering Research Center of Radiographic Techniques and Equipment, Institute of High Energy Physics, Chinese Academy of Sciences, Beijing, People's Republic of China.
Phys Med Biol. 2020 Dec 2;65(23):235039. doi: 10.1088/1361-6560/abb171.
In computed tomography, high attenuation occurs when x-rays pass through a dense region or a long path in the scanning object. In this case, only limited photons reach the detector, which causes photon starvation artifacts. The artifacts usually appear as streaks along the directions with high attenuation. It might lower the discrimination of minor structures and lead to misdiagnosis. Applying a local filter to the projection data adaptively is a common solution, however, if the parameters of projection-based filter are not well selected, new artifacts and noise might appear in the final image. In this paper, a post image processing technique was developed to suppress the photon starvation streak artifacts. Based on the directional characteristics of streaks, a semi-adaptive anisotropic diffusion filter was applied to the high frequency sub-bands after wavelet transformation (WASA). Qualitative and quantitative experiments were performed on phantom data and clinical data to prove the effectiveness of this method for photon starvation artifact suppression.
在计算机断层扫描中，当 X 射线穿过扫描物体的密集区域或长路径时，会出现高衰减。在这种情况下，只有有限的光子到达探测器，这会导致光子饥饿伪影。伪影通常表现为沿着高衰减方向的条纹。这可能会降低对小结构的辨别能力，并导致误诊。自适应地对投影数据应用局部滤波器是一种常见的解决方案，但是，如果投影滤波器的参数选择不当，则在最终图像中可能会出现新的伪影和噪声。本文提出了一种后图像处理技术来抑制光子饥饿条纹伪影。基于条纹的方向特征，在小波变换后（WASA）对高频子带应用半自适应各向异性扩散滤波器。在体模数据和临床数据上进行了定性和定量实验，以证明该方法对光子饥饿伪影抑制的有效性。
