论文标题
使用Pixirad-2/pixieiii光子计数检测器在常规实验室X射线微观图上使用Pixirad-2/Pixieiii光子计数检测器进行K边缘减去成像的最佳参数估计。
Optimal parameters estimation for K-edge subtraction imaging using PixiRad-2/PixieIII photon counting detector on a conventional laboratory X-ray micro-tomograph
论文作者
论文摘要
光子计数检测器（PCD）在X射线成像中开放了新的机会。 Pixie III是同时使用两个能量阈值的PCD。这使得可以在一次曝光中使用两个不同的能量箱获取图像，并允许使用实验室来源进行K边缘减法（KES）成像。但是，在这种情况下，必须处理一个能量箱优化：狭窄的能量箱导致高KES信号以牺牲较高的噪声为代价，而更宽的能量箱会导致KES信号较差，但统计数据更好。这项工作提出了一个模型，旨在找到最佳的能量阈值和源电压，以检索给定样品的最佳对比度（CNR）。该模型还优化了常规吸收方式的参数，并比较了这两种方式。由于输入通量和阈值之间的能量差会影响图像噪声，因此使用现象学定律将其包含在模型中。然后，通过使用由钡，碘和水组成的模型材料对参数进行实验筛选，将模型与经验优化进行比较。最后，解释了如何建模样品组成对预测的CNR值的影响。
Photon Counting Detectors (PCDs) open new opportunities in X-ray imaging. Pixie III is a PCD using simultaneously two energy thresholds. This enables to acquire images using two distinct energy bins in a single exposure and allows to perform K-Edge Subtraction (KES) imaging with laboratory sources. In that context, one has however to deal with an energy bin optimization: narrow energy bins lead to high KES signal at the expense of higher noise, while wider energy bins lead to poor KES signal but better statistics. This work presents a model that aims at finding the optimal energy thresholds and source voltage in order to retrieve the best Contrast to Noise Ratio (CNR) for a given sample. The model also optimizes the parameters for conventional absorption modality and compares both modalities. Since the input flux and the energy difference between the thresholds influence image noise, this is included in the model using phenomenological laws. The model is then compared to empirical optimization by experimental screening of the parameters using model materials composed of barium, iodine and water. Finally, it is explained how to model the influence of sample composition on the predicted CNR values.
