Optimization of Clinical and Research PET Imaging

这个项目的目标是定量地展示最新的 在现实的患者研究中使用任务特定图像质量测量的PET/CT系统，这些结果将 与更简单、更容易计算的指标的表现相关联。我们的目标是 在不牺牲现有系统的情况下，减少这些最新系统的注入活动或成像时间 临床能力或展示新的临床能力。评估将作为一项 扫描仪设计、图像重建和患者习惯的作用，以维持良好的临床 表现优于所有患者。目前，PET成像协议是基于或基于成像而设计的 接近峰值噪声当量计数(NEC)。虽然这些扫描仪的性能已经提高， 在减少成像时间的同时，患者注射方案保持不变。另外，虽然 NEC给出了总体像素信噪比(SNR)的估计值，以及它与临床相关性的关系 指标不是很明显，特别是因为它不包括空间和TOF分辨率的影响，以及 图像重建。在这个项目中，我们执行了一项临床现实研究，重复了以下两项任务 肿瘤学：(I)诊断PET中常见的病变检测和定位，以及(Ii)监测肿瘤 多次扫描对治疗的反应。我们在临床患者数据中嵌入病变后再进行成像 重建，从而提供一个可供比较的基本事实。建议的工作已经完成。 通过以下具体目标：(1)开发和评估用于优化的新的简化NEC指标 用于临床相关任务的PET图像，包括空间和TOF分辨率效果，并测试其 与特定任务指标的相关性，(2)对病变进行全面的人类观察者研究 检测和定位，以及(3)进行ROC研究，模拟肿瘤对治疗的反应。在 短期内，这项工作的结果将定量地证明， 最新的PET/CT(商业系统以及PennPET Explorer扫描仪)，从而允许更短的时间 成像时间和/或注射活动减少。特定于任务的指标结果与简化的指标结果的关联 成像指标也将为未来的PET系统设计和成像提供重要的工具 重建评估和优化--复杂的、针对具体任务的评估将不切实际。 在临床上，以非常短的扫描时间展示良好的性能将打开 屏气成像，无运动伪影。我们的结果还将使PET成像的扩展成为可能 进入新的临床领域，在这些领域，患者的辐射暴露是使用这种分子的限制因素 成像方式。我们设想连续的患者成像用于监测治疗反应，以及 对高危患者的筛查/监测研究，两个直接相关的领域。

The goal of this project is to quantitatively demonstrate improved clinical performance of the latest PET/CT systems using task-specific image quality measures in realistic patient studies These results will be correlated to the performance of simpler metrics that are easier to calculate. Our objective is to either guide a reduction in injected activity or imaging time on these latest systems without sacrificing existing clinical capabilities or to demonstrate new clinical capabilities. The evaluation will be performed as a function of scanner design, image reconstruction, and patient habitus in order to maintain good clinical performance over all patients. Currently, PET imaging protocols are designed based on imaging at or near the peak noise equivalent counts (NEC). While the performance of these scanners has improved, the patient injection protocols have remained constant while the imaging time is reduced. Also, while NEC gives an estimate of the general pixel signal-to-noise ratio (SNR), its relation to clinically relevant metrics is not obvious especially since it does not include the effects of spatial and TOF resolution, and image reconstruction. In this project we perform a clinically realistic study replicating two tasks in oncology: (i) lesion detection and localization common in diagnostic PET, and (ii) monitoring tumor response to therapy with multiple scans. Our embed lesions in clinical patient data prior to image reconstruction, thereby providing a ground-truth for comparison. The proposed work is accomplished through the following specific aims: (1) Develop and evaluate a new simplified NEC metric for optimizing PET images for clinically relevant tasks that includes spatial and TOF resolution effects and test its correlation to a task-specific metric, (2) Perform a comprehensive human observer study for lesion detection and localization, and (3) Perform a ROC study that models tumor response to therapy. In the short term, the results of this work will quantitatively demonstrate improved clinical performance with the latest PET/CT (commercial systems as well as PennPET Explorer scanner), thereby allowing shorter imaging times and/or reduced injected activity. Correlation of the task-specific metric results to simplified imaging metrics will also provide an important tool for future PET system design and image reconstruction evaluation and optimization where complex, task-specific evaluations will not be practical. Clinically, demonstration of good performance with very short scan times will open the possibility of breath-hold imaging with no motion artifacts. Our results will also enable an expansion of PET imaging into new clinical areas where patient radiation exposure is a limiting concern in the use of this molecular imaging modality. We envision serial patient imaging for monitoring treatment response, as well as screening/surveillance studies in high-risk patients, 2 areas of immediate relevance.