Optimization of x-ray dark-field CT for human-scale lung imaging

IF 3.2 2区医学 Q1 RADIOLOGY, NUCLEAR MEDICINE & MEDICAL IMAGING

Medical physics Pub Date : 2025-01-27 DOI:10.1002/mp.17630

Peiyuan Guo, Simon Spindler, Michal Rawlik, Jincheng Lu, Longchao Men, Mingzhi Hong, Marco Stampanoni, Hongxia Yin, Yan Xu, Zhenchang Wang, Li Zhang, Zhentian Wang

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引用次数: 0

Abstract

Background

X-ray grating-based dark-field imaging can sense the small angle scattering caused by object's micro-structures. This technique is sensitive to the porous microstructure of lung alveoli and has the potential to detect lung diseases at an early stage. Up to now, a human-scale dark-field CT (DF-CT) prototype has been built for lung imaging.

Purpose

This study aimed to develop a thorough optimization method for human-scale dark-field lung CT and guide the system design.

Methods

We introduced a task-based metric formulated as the contrast-to-noise ratio (CNR) between normal and lesioned alveoli for system parameter optimization and designed a digital human-thorax phantom to fit the task of lung disease detection. Furthermore, a computational framework was developed to model the signal propagation in DF-CT and established the link between system parameters and the CNR metric.

Results

We showed that for a DF-CT system, its CNR first increases and then decreases with the system auto-correlation length (ACL). The optimal ACL is mostly independent of system's visibility, and is only related to the phantom's properties, that is, its size and absorption. For our phantom, the optimal ACL is about 0.35 µm at the design energy of 60 keV. As for system geometry, increasing source-detector and isocenter-detector distance can extend the system's maximal ACL, making it easier for the system to meet the optimal ACL and relaxing the grating pitches. We proposed a set of parameters for a projective fringe system that can satisfy the simulated optimal ACL.

Conclusion

This study introduced a task-based metric and a process for DF-CT optimization. We demonstrated that for a given phantom, the detection performance of the system is optimized at a specific ACL. The optimization method and design principles are independent from the underlying dark-field imaging method and can be applied to DF-CT system design using different grating-based implementations such as Talbot-Lau interferometer (TLI) or projective fringe method.

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x射线暗场CT人体尺度肺成像的优化

背景：基于x射线光栅的暗场成像可以感知物体微观结构引起的小角度散射。该技术对肺泡的多孔结构敏感，具有早期发现肺部疾病的潜力。目前，用于肺部成像的人体尺度暗场CT （DF-CT）样机已经建立。目的：研究人体尺度肺暗场CT的全面优化方法，指导系统设计。方法：我们引入了一种基于任务的指标，即正常肺泡与病变肺泡之间的对比噪声比（CNR）来优化系统参数，并设计了一个数字人体胸腔模型来适应肺部疾病检测的任务。此外，建立了一个计算框架来模拟DF-CT中的信号传播，并建立了系统参数与CNR度量之间的联系。结果：我们发现，对于DF-CT系统，其CNR随系统自相关长度（ACL）先增大后减小。最优ACL大多与系统的可见性无关，只与幻影的特性有关，即它的大小和吸收。在设计能量为60 keV时，我们的模体的最佳ACL约为0.35µm。在系统几何上，增加源-检测器和等心-检测器的距离可以延长系统的最大ACL，使系统更容易满足最优ACL，并使光栅间距放松。我们提出了一组能满足模拟最优ACL的投影条纹系统参数。结论：本研究介绍了一种基于任务的DF-CT优化指标和流程。我们证明了对于给定的幻影，系统的检测性能在特定ACL下得到优化。优化方法和设计原则独立于底层的暗场成像方法，可以应用于DF-CT系统设计，使用不同的基于光栅的实现，如塔尔伯特-劳干涉仪（TLI）或投影条纹法。

本文章由计算机程序翻译，如有差异，请以英文原文为准。

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来源期刊

Medical physics 医学-核医学

CiteScore

6.80

自引率

15.80%

发文量

660

审稿时长

1.7 months

期刊介绍： Medical Physics publishes original, high impact physics, imaging science, and engineering research that advances patient diagnosis and therapy through contributions in 1) Basic science developments with high potential for clinical translation 2) Clinical applications of cutting edge engineering and physics innovations 3) Broadly applicable and innovative clinical physics developments Medical Physics is a journal of global scope and reach. By publishing in Medical Physics your research will reach an international, multidisciplinary audience including practicing medical physicists as well as physics- and engineering based translational scientists. We work closely with authors of promising articles to improve their quality.