Bittel Carmen A, MacDonald Carolyn A
Physics Department, University of Albany, State University of New York, Albany, United States of America.
Biomed Phys Eng Express. 2025 Jan 24;11(2). doi: 10.1088/2057-1976/ada9ed.
Conventional x-ray radiography relies on attenuation differences in the object, which often results in poor contrast in soft tissues. X-ray phase imaging has the potential to produce higher contrast but can be difficult to utilize. Instead of grating-based techniques, analyzer-based imaging, also known as diffraction enhanced imaging (DEI), uses a monochromator crystal with an analyzer crystal after the object. Analyzer-based systems most commonly employ synchrotron sources to provide adequate intensity, and typically use higher photon energies. In this work, a simulation has been devised to assess the potential for a polycapillary-based system. A polycapillary collimating optic has previously been shown to greatly enhance the intensity of the beam diffracted from the monochromatizing crystal. Detailed simulation of the optic is computationally intensive and requires comprehensive knowledge of the internal shape of the optic, so a simple geometric model using easier to obtain optic output data was developed and compared to the more detailed simulation. After verification, refraction band visibility was used as a quality parameter to address the effectiveness of the polycapillary-based DEI system at x-ray photon energies of 8 and 17.5 keV. The result shows promise for a polycapillary-coupled analyzer-based system even at low x-ray photon energy.
传统的X射线摄影依靠物体中的衰减差异，这常常导致软组织对比度不佳。X射线相成像有潜力产生更高的对比度，但可能难以应用。基于分析仪的成像，也称为衍射增强成像（DEI），不是采用基于光栅的技术，而是在物体之后使用一个单色器晶体和一个分析器晶体。基于分析仪的系统最常使用同步加速器源来提供足够的强度，并且通常使用更高的光子能量。在这项工作中，设计了一个模拟来评估基于多毛细管的系统的潜力。先前已表明，多毛细管准直光学器件能极大地增强从单色化晶体衍射的光束强度。对该光学器件进行详细模拟计算量很大，并且需要全面了解光学器件的内部形状，因此开发了一个使用更易获取的光学器件输出数据的简单几何模型，并与更详细的模拟进行比较。经过验证后，将折射带可见性用作质量参数，以评估基于多毛细管的DEI系统在8 keV和17.5 keV的X射线光子能量下的有效性。结果表明，即使在低X射线光子能量下，基于多毛细管耦合分析仪的系统也有前景。
