A synchronized moving grid (SMOG) system to improve CBCT for IGRT and ART

用于改进 IGRT 和 ART CBCT 的同步移动网格 (SMOG) 系统

• 批准号: 8677820
• 负责人: Jian-Yue Jin
• 金额: $ 36.54万
• 依托单位: AUGUSTA UNIVERSITY
• 依托单位国家: 美国
• 财政年份: 2012
• 资助国家: 美国
• 起止时间: 2012-07-09 至 2016-05-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/8677820
• 关键词: Address; Adverse effects; Affect; Algorithms; Cadaver; Clinical; Computer software; Cone; Data; Development; Devices; Diagnostic radiologic examination; Dose; Excision; Generations; Hand; Hepatocyte Growth Factor; Image; Image-Guided Surgery; Intervention; Lead; Measures; Medicine; Methods; Metric; Modeling; Monte Carlo Method; Morphologic artifacts; Motion; Noise; Organ; Patients; Pattern; Positioning Attribute; Procedures; Radiation; Radiation therapy; Research; Resolution; Rotation; Scanning; Second Primary Cancers; Shadowing (Histology); Simulate; Slice; Solutions; Source; System; Techniques; Testing; Thick; Validation; Width; X-Ray Computed Tomography; base; carcinogenesis; cone-beam computed tomography; data acquisition; detector; image guided radiation therapy; image registration; improved; innovation; prototype; reconstruction; simulation

DESCRIPTION (provided by applicant): This research plan proposes a synchronized-moving-grid (SMOG) system to improve the image quality of kilovoltage cone-beam computed tomography (kV CBCT). CBCT has the advantages over the conventional fan-beam computed tomography (CT) for its ability to acquire multiple slices of images in one rotation, and the spatial resolution and convenience gained by using a flat panel detector (FPD). The introduction of the FPD based CBCT in IGRT has significantly improved the accuracy of radiation treatment and may revolutionize the radiation therapy procedure. CBCT also has potential important applications in image guided surgery and intervention, and in diagnostic radiology for fast imaging of moving organs. However, three major problems-scatter, image lag and gantry flex-significantly degrade the image quality of CBCT, thereby hampering its further applications. Many methods have been proposed to reduce the scatter effect. These methods can be divided into two groups: (1) direct scatter reduction and (2) scatter correction. However, the efficiency o the current direct scatter reduction methods is often limited, and although scatter correction methods can reduce scatter artifacts, they usually further degrade the contrast-to-noise ratio. Various methods proposed to reduce the lag and flex effects have also shown only limited improvements due to the complexity of the issues at hand. The SMOG system aims to address these heretofore unresolved problems. It takes multiple partial- projections at each gantry position during a scan, with the grid moving rapidly in an oscillating pattern synchronized with the gantry motion. A full projection is obtained by merging all partial projections at the same gantry position. This approach not only provides a solution to the scatter problem through simultaneous scatter reduction and correction, it also effectively addresses lag and flex as well, allowing for the simultaneous resolution of all three major problems facing CBCT in one simple device. In addition, the SMOG system includes a software platform comprised of Monte-Carlo (MC)-based simulation and a compressed sensing algorithm that further optimizes the image quality. Preliminary results have demonstrated the applicability and promise of these concepts. For the scatter problem, we used multiple-rotation scans with the grid shifting a distance after each rotation to simulate the SMOG system. Significant improvement in the image quality-as demonstrated by increased CNR and removal of scatter artifacts-has been achieved. A simulation study also shows that the lag in the image region can be corrected by using the lag in the neighboring shadow region blocked by the septa. We have also shown that the grid can be used to directly detect the gantry wobbling distribution in a scan. The SMOG system will be developed and tested in a CBCT test bench, and then transferred to a clinical CBCT system for clinical validation.

描述（由申请人提供）：本研究计划提出了一种同步移动网格（SMOG）系统，以提高千伏锥束计算机断层扫描（kV CBCT）的图像质量。CBCT与传统的扇束计算机断层扫描（CT）相比，具有在一次旋转中获取多个切片图像的能力，以及通过使用平板探测器（FPD）获得的空间分辨率和方便性。在IGRT中引入基于FPD的CBCT显著提高了放射治疗的准确性，并可能彻底改变放射治疗程序。CBCT在图像引导手术和介入以及用于运动器官快速成像的诊断放射学中也具有潜在的重要应用。然而，散射、图像滞后和机架弯曲这三个主要问题严重降低了CBCT的图像质量，从而阻碍了CBCT的进一步应用。已经提出了许多方法来减少散射效应。这些方法可以分为两组：（1）直接散射减少和（2）散射校正。然而，当前的直接散射减少方法的效率通常是有限的，并且尽管散射校正方法可以减少散射伪影，但是它们通常进一步降低对比度噪声比。由于手头问题的复杂性，提出的减少滞后和弯曲效应的各种方法也仅显示出有限的改进。SMOG系统旨在解决这些迄今尚未解决的问题。它在扫描期间在每个机架位置处进行多个部分投影，其中网格以与机架运动同步的振荡模式快速移动。通过合并相同机架位置处的所有部分投影来获得完整投影。这种方法不仅通过同时减少和校正散射提供了散射问题的解决方案，而且还有效地解决了滞后和弯曲问题，允许在一个简单的设备中同时解决CBCT面临的所有三个主要问题。此外，SMOG系统包括一个软件平台，该平台由基于蒙特-卡罗（MC）的模拟和压缩传感算法组成，可进一步优化图像质量。初步结果表明，这些概念的适用性和承诺。对于散射问题，我们使用多次旋转扫描，每次旋转后网格移动一段距离来模拟SMOG系统。图像质量的显着改善-如CNR增加和散射伪影的去除所证明的-已经实现。仿真研究还表明，图像区域中的滞后可以通过使用被隔膜阻挡的相邻阴影区域中的滞后来校正。我们还表明，网格可以用来直接检测扫描中的机架摆动分布。SMOG系统将在CBCT测试台架上进行开发和测试，然后转移到临床CBCT系统进行临床验证。