Dynamic bowtie attenuator for CT dose reduction and dynamic range control

用于减少 CT 剂量和动态范围控制的动态领结衰减器

• 批准号: 8569072
• 负责人: NORBERT J. PELC
• 金额: $ 23.55万
• 依托单位: STANFORD UNIVERSITY
• 依托单位国家: 美国
• 财政年份: 2013
• 资助国家: 美国
• 起止时间: 2013-08-01 至 2015-07-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/8569072
• 关键词: Adopted; Adoption; Anatomy; Clinical; Complex; Computer Simulation; Computer software; Development; Diagnostic; Diagnostic Imaging; Dose; Engineering; Goals; Human; Image; Immunity; Individual; Industry; Investments; Knowledge; Lead; Lighting; Location; Measures; Medicine; Methods; Modification; Morphologic artifacts; Noise; Patients; Pattern; Performance; Photons; Physicians; Population; Property; Public Health; Radiation; Reproducibility; Research; Risk; Scanning; Scheme; Shapes; Signal Transduction; Simulate; Slice; Solutions; Source; Speed; System; Technology; Testing; Time; Tomography, Computed, Scanners; Translating; Variant; Work; X-Ray Computed Tomography; attenuation; clinical application; cost; cost effective; design; detector; falls; improved; meetings; prototype; public health relevance; research study; simulation; technological innovation

DESCRIPTION (provided by applicant): Computed Tomography (CT) has become a mainstay in diagnostic imaging. The high utility of CT has led to increased use and, as a result, to concerns about the radiation burden to individuals and the population. Although many technologies have been developed to reduce the dose from CT, further reductions are both possible and prudent, and the ALARA principle dictates that any reduction that is reasonably achievable should be adopted. Control of the incident radiation profile through the use of a pre-patient attenuator ("bowtie" filter) is known to reduce patient dose for a given level of image quality and also to reduce the dynamic range requirements and the effects of scatter. However, systems have at most a few attenuator shape choices and the filter is fixed during the scan. At best, they are optimal for circularly symmetric cylindrical objects. By contrast, patients' attenuation properties are rather irregular. In previous research we showed that dynamic control of the illumination profile can lead to significant dose reduction, but that work assumed the use of complex and expensive source arrays. By contrast, a dynamic attenuator would be a cost effective solution for achieving similar control in the illumination profile. Such a dynamic attenuator would tailor the radiation distribution for each patient, slice location, viewing directon, and clinical application. This is aligned with efforts toward personalized medicine. The key requirement is that the attenuator needs to be very adaptive and also provide smooth variation in flux. Prior designs fall short. We have developed a design concept that meets the modulation requirements by using movable wedge attenuators with triangular cross-sections that vary in the axial direction to produce piece-wise linear, dynamic profiles. Initial computer simulations predic large reductions in dose and in the dynamic range of the x-ray signal at the detector. The dose reduction would be of immediate benefit while the reduction in dynamic range would enable the earlier adoption of photon-counting detectors that would have additional benefits. In contrast to the source array approach, the dynamic bowtie is compatible with conventional CT system designs, so if viable it could be readily translated into clinical use. In the proposed research, w will conduct thorough computer simulations to optimize the design and predict performance benefits, build a portion of a dynamic attenuator array, and conduct experiments to validate the concept. Once this research is complete, the dynamic bowtie concept would be ready for adoption into commercial systems.

描述（由申请人提供）：计算机断层扫描（CT）已成为诊断成像的支柱。CT的高效用导致其使用量增加，结果引起了对个人和人群的辐射负担的担忧。虽然已经开发了许多技术来减少CT的剂量，但进一步的减少是可能的和谨慎的，ALARA原则规定，任何合理实现的减少都应该采用。通过使用患者前衰减器（“领结”滤波器）控制入射辐射剖面，已知可以降低给定图像质量水平下的患者剂量，还可以降低动态范围要求和散射的影响。然而，系统最多有几个衰减器形状选择，并且在扫描期间滤波器是固定的。在最好的情况下，它们是圆对称圆柱形物体的最佳选择。相比之下，患者的衰减特性相当不规则。在之前的研究中，我们表明，动态控制照明轮廓可以导致显著的剂量减少，但该工作假设使用复杂和昂贵的源阵列。相比之下，动态衰减器将是一个成本有效的解决方案，以实现类似的控制照明轮廓。这种动态衰减器将为每位患者量身定制辐射分布、切片位置、观察方向和临床应用。这与个性化医疗的努力是一致的。关键的要求是，衰减器需要非常自适应，也提供平滑的变化通量。先前的设计不足。我们开发了一种设计概念，通过使用具有三角形截面的可移动楔形衰减器来满足调制要求，这些衰减器在轴向上变化，以产生分段线性动态轮廓。最初的计算机模拟预测了探测器处剂量和x射线信号动态范围的大幅减少。剂量的减少将带来直接的好处，而动态范围的减少将使光子计数探测器能够更早地采用，这将带来额外的好处。与源阵列方法相比，动态领结与传统的CT系统设计兼容，因此如果可行，它可以很容易地转化为临床应用。在提出的研究中，我们将进行全面的计算机模拟来优化设计和预测性能效益，构建一部分动态衰减器阵列，并进行实验来验证该概念。一旦这项研究完成，动态领结概念将准备应用于商业系统。