论文标题
具有原型空间光谱过滤器的多对比度CT成像
Multi-Contrast CT Imaging with a Prototype Spatial-Spectral Filter
论文作者
论文摘要
由于相对于常规CT的材料歧视，光谱CT具有各种临床应用的潜力。许多临床和临床前光谱CT系统具有两个光谱通道，用于使用诸如拆卸，双层探测器或KVP转换等策略，用于双能CT。但是，有一些新兴的临床成像应用需要三个或更多的光谱灵敏度通道，例如，单次扫描中需要多种外源性对比剂。空间光谱过滤器是一种新的光谱CT技术，它使用X射线光束调制来提供更大的光谱多样性。该设备由一系列K边滤波器组成，该滤波器将X射线梁分为频谱变化的梁。该设计允许任意数量的光谱通道。但是，传统的两步重建分解方案通常无效，因为任何单个光谱通道的测量数据在投影域中稀少。取而代之的是，我们将基于单步模型的材料分解算法直接从光谱CT数据直接估算材料密度图像。在这项工作中，我们提出了与X射线CT测试台集成的原型空间光谱过滤器。该过滤器由锡，Erbium，Tantalum和Lead Filter Tiles组成，它们在空间上调节系统光谱灵敏度模式。对系统进行表征和建模后，我们对含有水，碘和Gadolinium溶液的多对比增强幻象进行了光谱CT扫描。我们介绍了所得的光谱CT数据以及通过基于模型的材料分解估计的材料密度图像...
Spectral CT has great potential for a variety of clinical applications due to the improved material discrimination with respect to conventional CT. Many clinical and preclinical spectral CT systems have two spectral channels for dual-energy CT using strategies such as split-filtration, dual-layer detectors, or kVp-switching. However, there are emerging clinical imaging applications which would require three or more spectral sensitivity channels, for example, multiple exogenous contrast agents in a single scan. Spatial-spectral filters are a new spectral CT technology which use x-ray beam modulation to offer greater spectral diversity. The device consists of an array of k-edge filters which divide the x-ray beam into spectrally varied beamlets. This design allows for an arbitrary number of spectral channels; however, traditional two-step reconstruction-decomposition schemes are typically not effective because the measured data for any individual spectral channel is sparse in the projection domain. Instead, we use a one-step model-based material decomposition algorithm to iteratively estimate material density images directly from spectral CT data. In this work, we present a prototype spatial-spectral filter integrated with an x-ray CT test-bench. The filter is composed of an array of tin, erbium, tantalum, and lead filter tiles which spatially modulate the system spectral sensitivity pattern. After the system was characterized and modeled, we conducted a spectral CT scan of a multi-contrast-enhanced phantom containing water, iodine, and gadolinium solutions. We present the resulting spectral CT data as well as the material density images estimated by model-based material decomposition...
