X-ray computed tomography (CT) is widely used in various fields, including medical, industrial, and fundamental scientific applications. Its quick ability to provide three-dimensional quantification of structures makes it a valuable tool. In addition to patient diagnostics, CT methods are employed for the investigation of varied samples. This includes in-depth analysis using high-resolution micro- and nano-CT imaging. However, X-ray CT techniques not only perform morphological characterization but also allow for the direct evaluation of the effective atomic number () and mass density () of the subject under investigation. These techniques collectively fall within the class of Spectral CT methods, encompassing single-energy, dual-energy, differential phase contrast, and photon counting detector CT. Spectral CT leverages data acquired from different radiation interaction phenomena to map and values. This paper presents a comprehensive overview of these methodologies, elucidating the underlying theory behind each. Furthermore, we review published studies centered on the development of theoretical formulations and diverse applications of the techniques. They cover formalism development, calibration methods, and reconstruction algorithms. Additionally, we introduce the commonly utilized equipment along with case studies in medical, mineralogical, and material fields, as well as biology and archaeology. These case studies will be thoroughly evaluated and discussed within the context of this paper.

中文翻译：

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用于有效原子序数和密度评估的 X 射线计算机断层扫描：综述


X 射线计算机断层扫描 (CT) 广泛应用于各个领域，包括医学、工业和基础科学应用。它快速提供结构三维量化的能力使其成为一个有价值的工具。除了患者诊断之外，CT 方法还用于研究各种样本。这包括使用高分辨率微米和纳米 CT 成像进行深入分析。然而，X 射线 CT 技术不仅可以进行形态表征，还可以直接评估所研究对象的有效原子序数 () 和质量密度 ()。这些技术共同属于光谱 CT 方法类别，包括单能、双能、微分相差和光子计数探测器 CT。能谱 CT 利用从不同辐射相互作用现象获取的数据来绘制地图和值。本文对这些方法进行了全面概述，阐明了每种方法背后的基本理论。此外，我们回顾了已发表的以理论表述的发展和技术的多样化应用为中心的研究。它们涵盖形式主义开发、校准方法和重建算法。此外，我们还介绍了常用设备以及医学、矿物学、材料领域以及生物学和考古学领域的案例研究。这些案例研究将在本文中进行彻底的评估和讨论。