arXivDaily arXiv每日学术速递 周一至周五更新
arXiv 2012.11374physics.med-pheess.IV
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双四分之一扫描的双能量CT重建

Dual-energy CT Reconstruction from Dual Quarter Scans

Wenkun Zhang, Ningning Liang, Linyuan Wang, Ailong Cai, Zhizhong Zheng, Chao Tang, Yizhong Wang, Lei Li, Bin Yan, Guoen Hu

摘要:

与传统的单能量计算机断层成像(CT)相比,双能量CT(DECT)提供了更好的材料区分,但大多数DECT成像系统需要在不同的X射线光谱的双全角度投影数据。放宽对数据采集的要求是一个特别有吸引力的研究,以促进DECT在广泛的成像领域的应用。在这项工作中,我们设计了一种新的双四分之一扫描的DECT成像方案,并提出了一种有效的方法来重建所需的DECT图像从双有限角度投影数据,这使得DECT的成像配置与半扫描,并大大减少了扫描角度和辐射剂量。我们首先研究了双四分之一扫描方案下图像伪影的特点,发现DECT图像的方向性有限角伪影在图像域上是互补分布的,这是因为对应的高能和低能扫描的X射线是正交的。受这一发现的启发,通过将双四分之一扫描的有限角度DECT图像进行整合来生成融合CT图像。该策略在很大程度上减少了有限角度伪影,并保留了图像的边缘和内部结构。利用神经网络对非线性问题建模的能力,设计了一种单入口双输出结构的Anchor网络,从生成的融合CT图像中得到所需的DECT图像。仿真和实际数据的实验结果验证了该方法的有效性。

英文摘要:

Compared with conventional single-energy computed tomography (CT), dual-energy CT (DECT) provides better material differentiation but most DECT imaging systems require dual full-angle projection data at different X-ray spectra. Relaxing the requirement of data acquisition is a particularly attractive research to promote the applications of DECT in a wide range of imaging areas. In this work, we design a novel DECT imaging scheme with dual quarter scans and propose an efficient method to reconstruct the desired DECT images from dual limited-angle projection data, which enables DECT on imaging configurations with half-scan and largely reduces scanning angles and radiation doses. We first study the characteristics of image artifacts under dual quarter scans scheme, and find that the directional limited-angle artifacts of DECT images are complementarily distributed in image domain because the corresponding X-rays of high- and low-energy scans are orthogonal. Inspired by this finding, a fusion CT image is generated by integrating the limited-angle DECT images of dual quarter scans. This strategy largely reduces the limited-angle artifacts and preserves the image edges and inner structures. Utilizing the capability of neural network in the modeling of nonlinear problem, a novel Anchor network with single-entry double-out architecture is designed in this work to yield the desired DECT images from the generated fusion CT image. Experimental results on the simulated and real data verify the effectiveness of the proposed method.

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