Development and tuning of models for accurate simulation of CT spatial resolution using CatSim.
Development and tuning of models for accurate simulation of CT spatial resolution using CatSim.
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使用 CatSim 开发和调整模型以精确模拟 CT 空间分辨率。
DOI：
10.1088/1361-6560/ad2122
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发表时间：
2024
影响因子：
3.5
通讯作者：
DeMan,Bruno
中科院分区：
文献类型：
--
作者：
Zhang,Jiayong;Wu,Mingye;FitzGerald,Paul;Araujo,Stephen;DeMan,Bruno
我们试图系统地评估CatSim的能力，准确地模拟一个典型的64探测器行临床CT扫描仪在投影和图像域产生的空间分辨率，在临床使用的X射线techniques.ApproachUsing一个64探测器行临床扫描仪的范围内，我们扫描了两个phantomy设计，以评估投影和图像域的空间分辨率。这些经验扫描是在标准临床使用的X射线技术范围（kV和mA）内进行的。我们从扫描仪中提取投影数据，然后重建图像。对于CatSim模拟，我们开发了数字幻影来表示经验扫描中使用的幻影。我们开发了一个新的，现实的模型的X射线源焦点，我们凭经验调整的X射线探测器的时间响应公布的模型。我们应用这些幻影和模型来模拟相当于经验扫描的扫描，并使用与经验扫描相同的方法重建模拟投影。对于经验和模拟扫描，我们定性和定量地比较了投影域和图像域点扩散函数（PSF）以及图像域调制传递函数。我们报告了四个定量指标和百分之误差之间的经验和模拟results.Main ResultsQualcomm，PSF匹配以及在投影和图像域。在定量方面，所有四个指标通常一致，所有X射线技术的大多数平均误差基本上小于5%。虽然错误往往会增加降低kV，我们发现，CatSim模拟同意与经验扫描的限制所需的预期应用CatSim.SignificanceThe新的焦点模型和新的探测器的时间响应模型是显着的贡献CatSim，因为它们能够实现所需的经验和模拟结果之间的协议水平。通过这些新模型和验证，CatSim用户可以确信，模拟所表示的空间分辨率在合理的已知范围内忠实地代表了真实的扫描仪所获得的结果。此外，CatSim的用户可以改变参数，包括但不限于系统几何结构、焦斑尺寸/形状和探测器参数，超出物理扫描仪中可用的值，并对结果充满信心。因此，CatSim可用于探索新的硬件设计以及新的扫描和重建方法，从而加速改进CT扫描功能。
ObjectiveWe sought to systematically evaluate CatSim's ability to accurately simulate the spatial resolution produced by a typical 64-detector-row clinical CT scanner in the projection and image domains, over the range of clinically used x-ray techniques.ApproachUsing a 64-detector-row clinical scanner, we scanned two phantoms designed to evaluate spatial resolution in the projection and image domains. These empirical scans were performed over the standard clinically used range of x-ray techniques (kV, and mA). We extracted projection data from the scanner, and we reconstructed images. For the CatSim simulations, we developed digital phantoms to represent the phantoms used in the empirical scans. We developed a new, realistic model for the x-ray source focal spot, and we empirically tuned a published model for the x-ray detector temporal response. We applied these phantoms and models to simulate scans equivalent to the empirical scans, and we reconstructed the simulated projections using the same methods used for the empirical scans. For the empirical and simulated scans, we qualitatively and quantitatively compared the projection-domain and image-domain point-spread functions (PSFs) as well as the image-domain modulation transfer functions. We reported four quantitative metrics and the percent error between the empirical and simulated results.Main ResultsQualitatively, the PSFs matched well in both the projection and image domains. Quantitatively, all four metrics generally agreed well, with most of the average errors substantially less than 5% for all x-ray techniques. Although the errors tended to increase with decreasing kV, we found that the CatSim simulations agreed with the empirical scans within limits required for the anticipated applications of CatSim.SignificanceThe new focal spot model and the new detector temporal response model are significant contributions to CatSim because they enabled achieving the desired level of agreement between empirical and simulated results. With these new models and this validation, CatSim users can be confident that the spatial resolution represented by simulations faithfully represents results that would be obtained by a real scanner, within reasonable, known limits. Furthermore, users of CatSim can vary parameters including but not limited to system geometry, focal spot size/shape and detector parameters, beyond the values available in physical scanners, and be confident in the results. Therefore, CatSim can be used to explore new hardware designs as well as new scanning and reconstruction methods, thus enabling acceleration of improved CT scan capabilities.