Grating-based phase contrast tomosynthesis imaging: Proof-of-concept experimental studies
Grating-based phase contrast tomosynthesis imaging: Proof-of-concept experimental studies
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DOI：
10.1118/1.4835455
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发表时间：
2014-01-01
期刊：
影响因子：
3.8
通讯作者：
Chen, Guang-Hong
中科院分区：
文献类型：
--
作者：
Li, Ke;Ge, Yongshuai;Chen, Guang-Hong
目的：本文讨论了使用基于光栅的 DPC 台式实验系统进行 X 射线微分相衬 (DPC) 断层合成成像的可行性，该实验系统配备了商用数字平板探测器和医用级旋转阳极 X 射线管。为了量化其成像性能，进行了广泛的系统表征。方法：台式系统的主要组件包括具有 1.0 mm 标称焦斑尺寸的诊断 X 射线管、具有 96 μm 像素间距的平板探测器、在 +/- 30 度的有限角跨度内旋转的样品台以及具有三个 X 射线光栅的 Talbot-Lau 干涉仪。总共使用3个增量获取的21个投影视图来重建三组断层合成图像体积，包括使用带有斜坡核的滤波反投影（FBP）算法重建的传统吸收对比断层合成图像体积（AC-tomo）、使用带有希尔伯特核的FBP重建的相衬断层合成图像体积（PC-tomo）以及使用移位加法算法。使用三个包含组织替代材料的内部物理体模来表征信号线性、信号差噪比 (SDNR)、三维噪声功率谱 (3D NPS) 和穿面伪影扩散函数 (ASF)。结果：虽然 DPC-tomo 突出显示图像对象中的边缘和界面，但 PC-tomo 消除了 DPC 投影数据的微分性质，其像素值与图像实部的减量呈线性相关。 X射线折射率。在AC-tomo中，水中聚甲醛和油中聚苯乙烯的SDNR值分别为1.5和1.0，而在PC-tomo中，这些值分别提高到3.0和2.0。 PC-tomo 和 AC-tomo 表现出等效的 ASF，但由于断层合成图像重建算法的差异，它们由 3D NPS 量化的噪声特性被发现不同。结论：使用基于光栅的数据采集装置同时生成 X 射线微分相差、相差和吸收对比断层合成图像是可行的。该方法有望提高几种低密度材料的可见度，因此值得进一步研究。 (C) 2014 年美国医学物理学家协会。
Purpose: This paper concerns the feasibility of x-ray differential phase contrast (DPC) tomosynthesis imaging using a grating-based DPC benchtop experimental system, which is equipped with a commercial digital flat-panel detector and a medical-grade rotating-anode x-ray tube. An extensive system characterization was performed to quantify its imaging performance.Methods: The major components of the benchtop system include a diagnostic x-ray tube with a 1.0 mm nominal focal spot size, a flat-panel detector with 96 mu m pixel pitch, a sample stage that rotates within a limited angular span of +/- 30 degrees, and a Talbot-Lau interferometer with three x-ray gratings. A total of 21 projection views acquired with 3. increments were used to reconstruct three sets of tomosynthetic image volumes, including the conventional absorption contrast tomosynthesis image volume (AC-tomo) reconstructed using the filtered-backprojection (FBP) algorithm with the ramp kernel, the phase contrast tomosynthesis image volume (PC-tomo) reconstructed using FBP with a Hilbert kernel, and the differential phase contrast tomosynthesis image volume (DPC-tomo) reconstructed using the shift-and-add algorithm. Three inhouse physical phantoms containing tissue-surrogate materials were used to characterize the signal linearity, the signal difference-to-noise ratio (SDNR), the three-dimensional noise power spectrum (3D NPS), and the through-plane artifact spread function (ASF).Results: While DPC-tomo highlights edges and interfaces in the image object, PC-tomo removes the differential nature of the DPC projection data and its pixel values are linearly related to the decrement of the real part of the x-ray refractive index. The SDNR values of polyoxymethylene in water and polystyrene in oil are 1.5 and 1.0, respectively, in AC-tomo, and the values were improved to 3.0 and 2.0, respectively, in PC-tomo. PC-tomo and AC-tomo demonstrate equivalent ASF, but their noise characteristics quantified by the 3D NPS were found to be different due to the difference in the tomosynthesis image reconstruction algorithms.Conclusions: It is feasible to simultaneously generate x-ray differential phase contrast, phase contrast, and absorption contrast tomosynthesis images using a grating-based data acquisition setup. The method shows promise in improving the visibility of several low-density materials and therefore merits further investigation. (C) 2014 American Association of Physicists in Medicine.