Design and evaluation of a grid reciprocation scheme for use in digital breast tomosynthesis.
Design and evaluation of a grid reciprocation scheme for use in digital breast tomosynthesis.
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用于数字乳腺断层合成的网格往复方案的设计和评估。
DOI：
10.1117/12.2216248
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发表时间：
2016
期刊：
影响因子：
--
通讯作者：
Williams,MarkB
中科院分区：
文献类型：
--
作者：
Patel,Tushita;Sporkin,Helen;Peppard,Heather;Williams,MarkB
这项工作描述了一种方法，有效地消除散射辐射在数字乳腺断层合成摄影（DBT）。该方法的目标是通过最小化栅格往复运动期间栅格焦点（GFP）和X射线焦斑（XFS）的未对准来实现栅格图像遮蔽，而不会大幅增加辐射剂量。在双模态乳腺断层合成（DMT）扫描仪上构建并测试了运动方案的硬件，该扫描仪在单个机架上结合了DBT和分子乳腺断层合成（MBT）。DMT扫描仪使用管和X射线探测器的完全等中心旋转，以在DBT成像期间保持固定的管-探测器对准。测试了具有80 cm焦距、3.85 mm高度、0.1 mm厚薄片和1.1 mm孔间距的蜂窝聚焦铜原型栅格。在28 kV管电压下，电网的一次传输平均为74%，电网静止并对准最大传输。通过所提出的方法，在网格往复运动期间，它下降到72%。投影视图和重建DBT图像中的残余网格线伪影（GLAs）的特征在于，通过投影图像平场校正和DBT切片的基于空间频率的滤波来降低重建体积中GLAs的可见性的方法被描述和评价。软件校正方法降低了重建体积中这些伪影的可见性，使其在重建的DBT图像及其傅立叶变换中都不可察觉。
This work describes a methodology for efficient removal of scatter radiation during digital breast tomosynthesis (DBT). The goal of this approach is to enable grid image obscuration without a large increase in radiation dose by minimizing misalignment of the grid focal point (GFP) and x-ray focal spot (XFS) during grid reciprocation. Hardware for the motion scheme was built and tested on the dual modality breast tomosynthesis (DMT) scanner, which combines DBT and molecular breast tomosynthesis (MBT) on a single gantry. The DMT scanner uses fully isocentric rotation of tube and x-ray detector for maintaining a fixed tube-detector alignment during DBT imaging. A cellular focused copper prototype grid with 80 cm focal length, 3.85 mm height, 0.1 mm thick lamellae, and 1.1 mm hole pitch was tested. Primary transmission of the grid at 28 kV tube voltage was on average 74% with the grid stationary and aligned for maximum transmission. It fell to 72% during grid reciprocation by the proposed method. Residual grid line artifacts (GLAs) in projection views and reconstructed DBT images are characterized and methods for reducing the visibility of GLAs in the reconstructed volume through projection image flat-field correction and spatial frequency-based filtering of the DBT slices are described and evaluated. The software correction methods reduce the visibility of these artifacts in the reconstructed volume, making them imperceptible both in the reconstructed DBT images and their Fourier transforms.