Ultrafast Z-Scan X-ray Volume CT

超快 Z 扫描 X 射线体积 CT

• 批准号: 6724851
• 负责人: Charles A. Mistretta
• 金额: $ 14.51万
• 依托单位: UNIVERSITY OF WISCONSIN-MADISON
• 依托单位国家: 美国
• 财政年份: 2003
• 资助国家: 美国
• 起止时间: 2003-04-01 至 2005-03-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/6724851
• 关键词: X ray; angiography; bioimaging /biomedical imaging; computed axial tomography; coronary artery; imaging /visualization /scanning; magnetic resonance imaging; whole body imaging /scanning

DESCRIPTION (provided by applicant): Present computed tomography systems provide limited temporal resolution. Large spatial coverage requires sequential acquisition of slices as the patient table passes through a narrow region of exposure. This is true for helical CT scanners as well as electron beam CT (EBCT). There are several consequences of this. For contrast enhanced angiographic studies or studies of tumor contrast uptake, there is little dynamic information available at any anatomical location and the timing of the acquisition relative to the contrast arrival can be variable from patient to patient. For coronary artery imaging the need to acquire substantial sectors of angular data during the acquisition of each slice as the table moves past the source leads to coronary artery motion during acquisition times on the order of fifty milliseconds, even when EBCT is used. Failure to properly advance the sector in sequential heartbeats can lead to inadequate angular sampling and technically unacceptable examinations. Recently, several groups have begun to investigate volume CT systems using conventional x-ray tubes rotated in a single circular path with an opposed flat panel X-ray detector in conjunction with table motion. Although this increases the useful detection solid angle it does not provide optimal source trajectories for dynamic imaging over large fields of view. We propose to investigate the feasibility of an advanced CT system in which the x-ray focal spot is rapidly varied along the length (Z dimension) of the patient during gantry rotation (Z-Scan). This will be accomplished by means of a scanning electron beam or a linear array of discrete focal spots producing a flexible distribution of cone beam sources opposed by large detector arrays. Source trajectories can be optimized for particular clinical applications. The availability of arbitrary source trajectories wilt permit large volume dynamic time resolved detection of contrast material dynamics without significant table motion and, for coronary artery imaging, will permit a short exposure times in each cardiac phase. We will investigate the extension to X-ray CT of MRI acquisition schemes that have enabled us to acquire contrast-enhanced MR images with speeds up to a factor of forty faster than with conventional Cartesian MRI. In the R21 phase, the potential performance of systems based on the proposed approach will be studied using simulations. Measurements and image reconstructions wilt be generated using an X-ray test bed in which a conventional source will be moved to simulate the contemplated source trajectories. In the R33 phase a source test bed employing scanned electron beam technology or distributed pulsed sources will be developed. Potential applications of the contemplated scanner include dynamic studies of tumor contrast uptake, time resolved CT angiography, and coronary artery imaging. We will focus on the latter two applications and, based on the proposed studies, will develop a design for an optimized scanner based on the Z-Scan principle.

描述（由申请人提供）： 当前的计算机断层扫描系统提供有限的时间分辨率。大型空间覆盖范围需要顺序获得切片，因为患者桌子穿过狭窄的暴露区域。对于螺旋CT扫描仪以及电子束CT（EBCT）是正确的。这有几个后果。为了增强对比度的血管造影研究或肿瘤对比摄取的研究，在任何解剖位置几乎没有动态信息，而相对于对比度到达的收购的时机可以从患者到患者变化。对于冠状动脉成像，在获得每个切片期间，当桌子超过源源时，在获取源时，在获取过程中，在获取时间上，即使使用EBCT，则需要在每个切片中获取大量的角度扇区。无法在顺序心跳中正确推进该部门会导致角度采样不足和技术不可接受的检查。 最近，几个小组已经开始使用传统的X射线试管在单个圆形路径上旋转的常规X射线管进行研究，并与表运动结合使用，具有相反的平板X射线检测器。尽管这增加了有用的检测实体角度，但它并不能为在大型视野上的动态成像提供最佳的源轨迹。 我们建议研究高级CT系统的可行性，在该系统中，X射线焦点在龙门旋转过程中沿患者的长度（z维度）迅速变化（Z-SCAN）。这将通过扫描电子束或离散焦点线性阵列来实现，从而产生与大检测器阵列相反的锥形光束源的柔性分布。可以针对特定的临床应用优化源轨迹。任意源轨迹的可用性wilt允许大量动态时间解析对比度材料动力学的检测，而无需表现出明显的表现，并且对于冠状动脉成像，将允许在每个心脏阶段的暴露时间短。 我们将调查MRI采集方案的X射线CT扩展，这使我们能够以比传统的笛卡尔MRI的速度更快地获取对比度增强的MR图像。 在R21阶段，将使用仿真研究基于建议方法的系统的潜在性能。使用X射线测试床生成测量和图像重建，其中将移动传统源以模拟所谓的源轨迹。在R33期中，将开发使用扫描的电子束技术或分布式脉冲源的源测试床。 预期的扫描仪的潜在应用包括对肿瘤对比摄取的动态研究，时间分辨的CT血管造影和冠状动脉成像。我们将重点关注后两个应用程序，并基于拟议的研究，将根据Z-SCAN原理为优化的扫描仪开发设计。