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: 8400029
• 负责人: Jian-Yue Jin
• 金额: $ 41.57万
• 依托单位: HENRY FORD HEALTH SYSTEM
• 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/8400029
• 关键词: Address; Adverse effects; Affect; Algorithms; Cadaver; Clinical; Computer software; Data; Development; Devices; Diagnostic radiologic examination; Dose; Excision; Generations; Hand; Hepatocyte Growth Factor; Image; Image-Guided Surgery; Intervention; Lead; Measures; Medicine; Methods; Metric; Modeling; Morphologic artifacts; Motion; Noise; Organ; Patients; Pattern; Positioning Attribute; Procedures; Radiation; Radiation therapy; Research; Resolution; Retinal Cone; 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 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. PUBLIC HEALTH RELEVANCE: This study proposes a synchronized moving grid (SMOG) system to solve scatter, image lag and gantry flex, the three major problems in current clinical cone beam computed tomography (CBCT) with a same device. The SMOG system will vastly improve the image quality toward the second generation CBCT scanner for adaptive radiotherapy. We will build a prototype system and test it in the clinical setting.

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）系统来提高千伏锥形束计算机断层扫描（kV CBCT）的图像质量。 CBCT 相对于传统扇形束计算机断层扫描 (CT) 的优势在于，它能够在一次旋转中获取多个切片图像，并且通过使用平板探测器 (FPD) 获得空间分辨率和便利性。在 IGRT 中引入基于 FPD 的 CBCT 显着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 在图像引导手术和干预以及移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，分散、图像滞后和龙门弯曲这三个主要问题严重降低了CBCT的图像质量，从而阻碍了其进一步应用。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，当前直接散射减少方法的效率通常是有限的，并且虽然散射校正方法可以减少散射伪影，但它们通常进一步降低对比度与噪声比。由于问题的复杂性，提出的各种减少滞后和弯曲效应的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。在扫描期间，它在每个机架位置进行多次部分投影，网格以与机架运动同步的振荡模式快速移动。通过合并同一龙门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来解决散射问题，而且还有效地解决了滞后和弯曲问题，从而可以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系统还包括一个由基于蒙特卡罗（MC）的模拟和压缩感知算法组成的软件平台，可进一步优化图像质量。初步结果证明了这些概念的适用性和前景。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烟雾系统。图像质量得到了显着改善——如 CNR 的增加和散射伪影的消除所证明的那样——已经实现。模拟研究还表明，可以利用被隔膜阻挡的相邻阴影区域中的滞后来校正图像区域中的滞后。我们还表明，网格可用于直接检测扫描中的龙门摆动分布。 SMOG系统将在CBCT测试台上进行开发和测试，然后转移到临床CBCT系统进行临床验证。 公共健康相关性：本研究提出了一种同步移动网格（SMOG）系统，以解决当前临床锥形束计算机断层扫描（CBCT）中同一设备的三个主要问题：散射、图像滞后和机架弯曲。 SMOG 系统将极大地提高用于自适应放射治疗的第二代 CBCT 扫描仪的图像质量。我们将构建一个原型系统并在临床环境中对其进行测试。