Single-Shot Quantitative X-ray Imaging Using a Primary Modulator and Dual-Layer Detector: Simulation and Phantom Studies.
Single-Shot Quantitative X-ray Imaging Using a Primary Modulator and Dual-Layer Detector: Simulation and Phantom Studies.
复制标题
使用主调制器和双层探测器的单次定量 X 射线成像：模拟和模型研究。
DOI：
10.1117/12.2611591
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发表时间：
2022
期刊：
影响因子：
--
通讯作者：
Wang,AdamS
中科院分区：
文献类型：
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作者：
Shi,Linxi;Bennett,NRobert;Wang,AdamS
由于散射、光束硬化和组织重叠，传统的 X 射线成像几乎无法提供定量信息。先前开发了单次定量 X 射线成像 (SSQI) 方法，通过结合使用主调制器 (PM) 和双层 (DL) 探测器来量化 X 射线成像中的材料特定密度。使用基于迭代补丁的方法进行模拟证明了这一概念的可行性。在这项工作中，我们提出了一种新的 SSQI 算法管道，可以实现准确的量化和高计算效率。 DL 图像包含在每层 PM 的未衰减和部分衰减区域后面获得的四个测量值。利用散射的低频特性和预校准的材料分解 (MD)，通过直接求解由四个测量给出的四个方程来联合恢复四个未知数（即两个散射图像和两个特定材料图像）。我们在模拟中测试了该算法，并进一步证明了其在胸部模型实验中的功效。通过仿真，我们证明了 MD 的新方法对于散射具有鲁棒性。其性能随着更小的保偏间距尺寸和更小的焦点模糊而提高。与没有散射校正的情况相比，特定材料图像中的 RMSE 与地面实况相比降低了 52%-84%。在我们的实验研究中，我们成功地分离了软组织和骨骼。在没有优化的情况下，处理每个视图的计算时间约为 8 秒。报告的结果进一步增强了 SSQI 广泛采用的潜力，不仅可以用于 X 射线成像，还可以用于实时图像引导或锥束 CT 的定量成像。
Conventional x-ray imaging provides little quantitative information due to scatter, beam hardening, and overlaying tissues. A single-shot quantitative x-ray imaging (SSQI) method was previously developed to quantify material-specific densities in x-ray imaging by combining the use of a primary modulator (PM) and dual-layer (DL) detector. The feasibility of this concept was demonstrated with simulations using an iterative patch-based method. In this work, we propose a new algorithm pipeline for SSQI that enables accurate quantification and high computational efficiency. The DL images contain four measurements that are obtained behind the unattenuated and partially attenuated regions of the PM of each layer. Using the low-frequency property of scatter and a precalibrated material decomposition (MD), four unknowns (i.e., two scatter images and two material-specific images) are jointly recovered by directly solving four equations given by the four measurements. We tested this algorithm in simulations and further demonstrated its efficacy on chest phantom experiments. Through simulation, we show that the new method for MD is robust against scatter. Its performance improves with smaller PM pitch size and smaller focal spot blur. The RMSE in material-specific images compared to ground truth reduces by 52%-84% versus without scatter correction. For our experimental study, we successfully separated soft tissue and bone. The computational time for processing each view was ~8 s without optimization. The reported results further strengthen the potential of SSQI for widespread adoption, leading to quantitative imaging not only for x-ray imaging but also for real-time image guidance or cone-beam CT.