Varying collimation for dark-field extraction.
Varying collimation for dark-field extraction.
复制标题
暗场提取的不同准直。
DOI：
10.1155/2009/847537
复制
发表时间：
2009
影响因子：
7.6
通讯作者：
Zou,Yu
中科院分区：
文献类型：
--
作者：
Wang,Ge;Cong,Wenxiang;Shen,Haiou;Zou,Yu
尽管X射线成像广泛用于生物医学应用，但生物软组织的密度变化很小，导致基于衰减的X射线成像的对比度分辨率较低。在过去的几年里，X射线小角散射被研究为一种新的对比机制，以增强软组织内的细微结构变化。在本文中，我们提出了一种检测方法来提取这种类型的X射线散射数据，也被称为暗场信号。其关键思想是在X射线探测器阵列之前多次采集具有不同准直的X射线投影。利用足够高的准直纵横比的准直器采集的投影数据主要包含具有很少散射的初级射束，而利用适当减小的准直纵横比采集的数据包括初级射束和小角度散射信号两者。然后，对这些相应数据集的分析将产生所需的暗场信号;例如，通过数字减影。在数值实验中，我们的暗场检测技术的可行性证明在蒙特卡罗模拟。结果表明，所获得的暗场信号能够清晰地反映生物组织的瑞利散射特性。
Although x‐ray imaging is widely used in biomedical applications, biological soft tissues have small density changes, leading to low contrast resolution for attenuation‐based x‐ray imaging. Over the past years, x‐ray small‐angle scattering was studied as a new contrast mechanism to enhance subtle structural variation within the soft tissue. In this paper, we present a detection method to extract this type of x‐ray scattering data, which are also referred to as dark‐field signals. The key idea is to acquire an x‐ray projection multiple times with varying collimation before an x‐ray detector array. The projection data acquired with a collimator of a sufficiently high collimation aspect ratio contain mainly the primary beam with little scattering, while the data acquired with an appropriately reduced collimation aspect ratio include both the primary beam and small‐angle scattering signals. Then, analysis of these corresponding datasets will produce desirable dark‐field signals; for example, via digitally subtraction. In the numerical experiments, the feasibility of our dark‐field detection technology is demonstrated in Monte Carlo simulation. The results show that the acquired dark field signals can clearly reveal the structural information of tissues in terms of Rayleigh scattering characteristics.