Scatter radiation in digital tomosynthesis of the breast.
Scatter radiation in digital tomosynthesis of the breast.
复制标题
乳房数字断层合成中的散射辐射。
DOI：
10.1118/1.2428404
复制
发表时间：
2007
期刊：
影响因子：
3.8
通讯作者：
Karellas,Andrew
中科院分区：
文献类型：
--
作者：
Sechopoulos,Ioannis;Suryanarayanan,Sankararaman;Vedantham,Srinivasan;D'Orsi,CarlJ;Karellas,Andrew
正在研究乳房数字断层合成作为平面乳房X线摄影中存在的组织叠加问题的一种可能解决方案。这种成像技术具有多种优点，使其成为平面乳房X光检查的可行替代品，其中包括对乳房的辐射腺体剂量相似（如果不是更低）；通过相对简单的修改即可实现传统数字乳腺X线摄影技术；和快速的采集时间。然而，乳房断层合成必须克服的一个重要问题是减少投影图像中的 X 射线散射夹杂物。在断层合成中，由于投影几何形状和辐射剂量的考虑，抗散射栅格的使用提出了一些挑战。因此，使用基于采集后软件的散射减少算法似乎是合理的，需要对断层合成投影中的 X 射线散射内容进行综合评估。本研究旨在通过表征乳房断层合成中发现的散射点扩散函数 (PSF) 和散射与主比 (SPR) 图来深入了解断层合成中 X 射线散射的行为。该表征是使用基于 Geant4 工具包的蒙特卡罗模拟进行的，该工具包模拟数字断层合成系统中存在的条件，包括在头尾 (CC) 和中外侧斜 (MLO) 视图中模拟受压乳房。分析了散射 PSF 随断层合成投影角度的变化以及不同乳腺腺体分数和 X 射线光谱的影响。还分析了不同投影角度、乳房大小、厚度、腺体分数和 X 射线光谱的 SPR 行为，并找到了 CC 和 MLO 视图质心处 SPR 大小的计算机拟合方程。在乳房X线照相能量内，X射线光谱被发现对散射PSF和SPR没有明显影响。研究发现，腺体分数和压缩的乳房大小影响较小，而压缩的乳房厚度和投影角度（正如预期的那样）会在散射 PSF 和 SPR 中引入较大的变化。模拟中乳房支撑板和探测器盖板的存在对 SPR 产生了重要影响，这也与平面乳房 X 线摄影中的散射内容相关。
Digital tomosynthesis of the breast is being investigated as one possible solution to the problem of tissue superposition present in planar mammography. This imaging technique presents various advantages that would make it a feasible replacement for planar mammography, among them similar, if not lower, radiation glandular dose to the breast; implementation on conventional digital mammography technology via relatively simple modifications; and fast acquisition time. One significant problem that tomosynthesis of the breast must overcome, however, is the reduction of x‐ray scatter inclusion in the projection images. In tomosynthesis, due to the projection geometry and radiation dose considerations, the use of an antiscatter grid presents several challenges. Therefore, the use of postacquisition software‐based scatter reduction algorithms seems well justified, requiring a comprehensive evaluation of x‐ray scatter content in the tomosynthesis projections. This study aims to gain insight into the behavior of x‐ray scatter in tomosynthesis by characterizing the scatter point spread functions (PSFs) and the scatter to primary ratio (SPR) maps found in tomosynthesis of the breast. This characterization was performed using Monte Carlo simulations, based on the Geant4 toolkit, that simulate the conditions present in a digital tomosynthesis system, including the simulation of the compressed breast in both the cranio‐caudal (CC) and the medio‐lateral oblique (MLO) views. The variation of the scatter PSF with varying tomosynthesis projection angle, as well as the effects of varying breast glandular fraction and x‐ray spectrum, was analyzed. The behavior of the SPR for different projection angle, breast size, thickness, glandular fraction, and x‐ray spectrum was also analyzed, and computer fit equations for the magnitude of the SPR at the center of mass for both the CC and the MLO views were found. Within mammographic energies, the x‐ray spectrum was found to have no appreciable effect on the scatter PSF and on the SPR. Glandular fraction and compressed breast size were found to have a small effect, while compressed breast thickness and projection angle, as expected, introduced large variations in both the scatter PSF and SPR. The presence of the breast support plate and the detector cover plate in the simulations introduced important effects on the SPR, which are also relevant to the scatter content in planar mammography.