Super-Resolution PET Using Stepping of a Deliberately Misaligned Bed

使用故意错位床的步进进行超分辨率 PET

• 批准号: 8569816
• 负责人: SCOTT DEAN METZLER
• 金额: $ 20万
• 依托单位: UNIVERSITY OF PENNSYLVANIA
• 依托单位国家: 美国
• 财政年份: 2013
• 资助国家: 美国
• 起止时间: 2013-07-15 至 2015-06-30
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/8569816
• 关键词: Address; Algorithms; Animals; Beds; Biological Models; Brain; Characteristics; Clinical; Code; Computer software; Couples; Data; Drops; Evaluation; Evolution; Future; Image; Laboratories; Lesion; Manufacturer Name; Measures; Mechanics; Methods; Metric; Modeling; Morphologic artifacts; Motion; Motor; Movement; Noise; Patients; Pattern; Positioning Attribute; Positron-Emission Tomography; Radial; Recovery; Relative (related person); Research; Resolution; Sampling; Scanning; Side; Signal Transduction; Simulate; Solutions; Structure; System; Techniques; Testing; Time; Vendor; body system; clinically relevant; cost; data acquisition; design; detector; improved; novel; pre-clinical; public health relevance; reconstruction; response; retinal rods; simulation; statistics; wasting

DESCRIPTION (provided by applicant): The objective of this proposal is to test two hypotheses of the imaging characteristics of positron emission tomography (PET): (1) that substantial improvements in reconstruction accuracy can be obtained for whole-body PET systems by super-sampling voxels during acquisition through the near-continuous motion of the patient bed along a direction intentionally - but carefully and accurately - misaligned with respect to the scanner's axial direction; and (2) that super-sampling will allow resolution improvement with iterative algorithms using resolution-recovery techniques, beyond what those algorithms can achieve without super-sampling. Super-resolution through wobbling is a technique historically used in early brain PET systems to improve the sampling, which would typically improve resolution and reduce artifacts. With the introduction of block detectors and whole-body systems, wobbling disappeared because its mechanical cumbersomeness and added expense were not justified since the impact on reconstruction was negligible. This is because the block detectors greatly reduced the crystal size, reducing the importance of crystal size on overall system resolution in comparison with other effects such as acolinearity and signal distortions in readout. Thus, the sampling improved disproportionately to the resolution. Two significant changes have occurred since wobbling was removed from scanners: (1) 3D acquisitions greatly increased the count statistics, which supports the accurate reconstruction of smaller features; and (2) resolution-recovery iterative algorithms have become commonplace. We believe that improving sampling will result in increased accuracy and resolution of modern reconstructions while artifacts will be reduced because resolutions are once again becoming better in comparison to the sampling. We propose a novel method for increasing sampling, including axial sampling, that does not require additional hardware, making the solution possibly attractive to vendors for future systems and as low-cost upgrades to existing systems, if the hypotheses of this proposal are confirmed. The method introduces a small angle in the bed alignment combined with the use of existing bed motors to super-sample the object, requiring no additional scan time. When the bed moves axially, a small transaxial shift results. The specific aims of this proposal include: (i) determining through simulation the optimal stepping pattern and bed-alignment angle; (ii) modifying existing reconstruction software to incorporate the bed-position information; and (iii) experimentally test the method on a TOF research scanner, LaPET, that is in our laboratory. These aims will allow us to fully address the hypotheses of this proposal.

描述（申请人提供）：本提案的目的是检验正电子发射断层扫描（PET）成像特性的两个假设：（1）对于全身PET系统，可以通过在采集期间通过患者床沿着有意但仔细且准确的方向的接近连续的运动对体素进行超采样来获得重建准确性的实质性改进，相对于扫描仪的轴向方向未对准;以及（2）超采样将允许使用分辨率恢复技术的迭代算法的分辨率改进，超出那些算法在没有超采样的情况下可以实现的。通过摆动实现的超分辨率是一种历史上用于早期脑PET系统的技术，用于改善采样，这通常会提高分辨率并减少伪影。随着块检测器和全身系统的引入，摆动消失了，因为它的机械麻烦和增加的费用是不合理的，因为对重建的影响可以忽略不计。这是因为块检测器大大减小了晶体尺寸，与其他效应（例如读出中的共线性和信号失真）相比，降低了晶体尺寸对整个系统分辨率的重要性。因此，采样的改善与分辨率不成比例。自扫描仪消除摆动以来，发生了两个重大变化：（1）3D采集大大增加了计数统计，这支持了较小特征的准确重建;（2）分辨率恢复迭代算法已变得司空见惯。我们相信，改进采样将导致现代重建的精度和分辨率提高，同时伪影将减少，因为与采样相比，分辨率再次变得更好。我们提出了一种新的方法，增加采样，包括轴向采样，不需要额外的硬件，使解决方案可能有吸引力的供应商为未来的系统和低成本升级现有的系统，如果这个建议的假设得到证实。该方法在床对准中引入小角度，结合使用现有的床电机对对象进行超采样，不需要额外的扫描时间。当床轴向移动时，产生小的轴向位移。该建议的具体目标包括：（i）通过模拟确定最佳步进模式和床对齐角度;（ii）修改现有的重建软件，以纳入床位置信息;以及（iii）在我们实验室的TOF研究扫描仪LaPET上实验测试该方法。这些目标将使我们能够充分处理本提案的假设。