Mathews A J, Gang G, Levinson R, Zbijewski W, Kawamoto S, Siewerdsen J H, Stayman J W
Johns Hopkins University, Baltimore, MD USA.
Global Research and Advanced Development, Philips Healthcare, Haifa, Israel.
Proc SPIE Int Soc Opt Eng. 2017 Feb 11;10132. doi: 10.1117/12.2255677. Epub 2017 Mar 9.
Acquisition of CT images with comparable diagnostic power can potentially be achieved with lower radiation exposure than the current standard of care through the adoption of hardware-based fluence-field modulation (e.g. dynamic bowtie filters). While modern CT scanners employ elements such as static bowtie filters and tube-current modulation, such solutions are limited in the fluence patterns that they can achieve, and thus are limited in their ability to adapt to broad classes of patient morphology. Fluence-field modulation also enables new applications such as region-of-interest imaging, task specific imaging, reducing measurement noise or improving image quality. The work presented in this paper leverages a novel fluence modulation strategy that uses "Multiple Aperture Devices" (MADs) which are, in essence, binary filters, blocking or passing x-rays on a fine scale. Utilizing two MAD devices in series provides the capability of generating a large number of fluence patterns via small relative motions between the MAD filters. We present the first experimental evaluation of fluence-field modulation using a dual-MAD system, and demonstrate the efficacy of this technique with a characterization of achievable fluence patterns and an investigation of experimental projection data.
通过采用基于硬件的注量场调制（例如动态蝴蝶结滤波器），有可能以低于当前标准护理的辐射剂量获得具有可比诊断能力的CT图像。虽然现代CT扫描仪采用了诸如静态蝴蝶结滤波器和管电流调制等元件，但这些解决方案在所能实现的注量模式方面存在局限性，因此在适应广泛类别的患者形态方面能力有限。注量场调制还能实现新的应用，如感兴趣区域成像、特定任务成像、降低测量噪声或提高图像质量。本文介绍的工作利用了一种新颖的注量调制策略，该策略使用“多孔径装置”（MAD），本质上是二进制滤波器，在精细尺度上阻挡或透过X射线。串联使用两个MAD装置能够通过MAD滤波器之间的小相对运动生成大量注量模式。我们展示了使用双MAD系统对注量场调制的首次实验评估，并通过对可实现的注量模式进行表征以及对实验投影数据进行研究，证明了该技术的有效性。
