Development of Spectral Phase Contrast Micro-CT

能谱X射线相衬显微CT的研制 项目摘要 体内微型CT的一个具有挑战性的方面涉及所需的有害辐射剂量水平--特别是 对于需要纵向跟踪同一主题的研究。主要的制约因素是衰减较差 软组织中X光的对比度和成像时间需要较长。研究人员已经研究了如何使用 使用Micro-CT系统进行材料分解的多能量(或光谱)X射线采集，但 这些方法的多功能性再次受到相同对比剂量权衡的限制。位相衬度成像 (PCI)可以在较高能量下提供显著的相位增强对比度，因此潜在地降低了Micro-CT 剂量。然而，现有的pci方法仍然需要高剂量和长时间的成像来获得准确的相位。 取回。我们最近开发了一种光谱pci的算法方法，使剂量和成像成为可能。 与衰减成像相称的时间。我们的假设是，经皮冠状动脉介入治疗是在正常的临床条件下进行的 约束可以在比衰减更低的剂量下产生更好的组织定量和更小的特征描绘 成像。我们将开发一种独特的光谱Micro-CT系统，同时具有PCI和非PCI功能来测试 这个假说。一个关键的系统组件将是创新的高性能、高分辨率光子- 计数探测器(PCD)将由休斯顿大学和阿德卡姆公司根据这笔赠款共同开发 S.R.O.我们将评估两种非干涉的PCI几何形状。第一个具体目标是设计微型 基于源KVP和PCD传感器厚度、像素大小和能量等因素的CT系统 仓位配置。特定于PCI的标准包括放大倍数和x射线掩模属性。优化研究 将在PCI和非PCI模式下执行。对于目标2，我们将与AdVacam合作开发 系统采用了广域、高帧频、高Z的传感器PCD。高性能的PCD将是 基于MediPix3RX ASIC技术构建，将具有高分辨率和内置光谱 校正方案和快速读出。在目标3下，将建造微型CT单元并为其提供能源 将制定校准和校正方案，以实现有效的系统性能。我们的第四个特别节目 目的是比较频谱显微CT的PCI和非PCI模式与物理模体的性能 以及动物研究，以评估低对比敏感度的增强。利用脂质体进行体内研究 碘纳米粒子将检查经皮冠状动脉介入治疗区分血管治疗差异的能力- 小鼠前列腺癌模型的反应性和耐受性。

Development of Spectral X-Ray Phase-Contrast Micro-CT Project Summary A challenging aspect of in vivo micro-CT relates to the required deleterious radiation dose levels - particularly for studies required to follow the same subject longitudinally. The main constraint is the poor attenuation contrast for x-rays in soft tissue and the need for long imaging times. Researchers have studied the use of multi-energy (or spectral) x-ray acquisitions to perform material decomposition with micro-CT systems, but the versatility of these methods is again constrained by the same contrast-dose trade-off. Phase-contrast imaging (PCI) can provide significant phase-enhanced contrast at higher energies, thus potentially reducing micro-CT dose. However, existing PCI methods still require high dose and long imaging times for accurate phase retrieval. We have recently developed an algorithmic approach to spectral PCI that enables dose and imaging times commensurate with attenuation imaging. Our hypothesis is that PCI performed under normal clinical constraints can yield better tissue quantitation and small feature delineation at lower dose than attenuation imaging. We shall develop a unique spectral micro-CT system with both PCI and non-PCI capabilities to test this hypothesis. A key system component will be an innovative high-performance, high-resolution photon- counting detector (PCD) to be developed jointly under this grant by the University of Houston and Advacam s.r.o. Two non-interferometric PCI geometries will be evaluated. The first specific aim is to design the micro- CT system based on considerations such as source kVp and the PCD sensor thickness, pixel size, and energy bin configuration. PCI-specific criteria include magnification and the x-ray mask properties. Optimization studies will be carried out for both the PCI and the non-PCI modes. For Aim 2, we will work with Advacam to develop the wide-area, high frame rate and high Z sensor PCD for the system. The high-performance PCD will be constructed based on Medipix3RX ASIC technology and will feature high resolution and built-in spectral correction schemes and fast readouts. Under Aim 3, the micro-CT unit will be constructed and energy calibration and correction schemes will be developed to allow efficient system performance. Our fourth specific aim is to compare the performance of the PCI and non-PCI modes of spectral micro-CT with physical phantoms and animal studies to evaluate the enhancement of low contrast sensitivity. In vivo studies using liposomal iodine nanoparticles will examine the ability of PCI to distinguish differences in blood vascularity for treatment- responsive and treatment-resistive prostate cancer models in mice.