End-to-End Optimization of SPECT Instrumentation, Acquisition, and Reconstruction

描述(申请人提供)：单光子发射计算机断层扫描在许多重要心脏疾病的诊断和分期中发挥着重要且得到充分验证的作用，并在美国和世界各地的许多临床地点广泛使用和提供。最常见的应用是心肌灌注SPECT来评估心血管疾病。一个新的和潜在的重要应用是I-123 MIBG SPECT(AdreView)，用于心肌神经成像。虽然已经有大量的工作来开发改进的重建方法，以及一些工作来开发优化的仪器和采集参数，但这些工作在很大程度上是相互独立地完成的。诸如：使用准直器响应补偿时，最佳的准直器是什么？有散射补偿的最佳能量窗是什么？对每个投影图使用相同的采集时间是否是最佳的？对每个患者使用相同的采集时间是否是最佳的？从未被提及过。此外，目前有一些专门用于心脏成像的扫描仪，它们结合了几个新的功能来减少采集时间。其中一些是基于碲化镉锌半导体探测器，这种探测器提供了改进的全宽半最大能量分辨率，但具有更复杂的能量响应，包括延伸到低能量的尾部。其他新的探测器材料，如具有更高能量分辨率的LABR，也即将问世。然而，CZT和LABR探测器的能量窗和散射补偿方法还没有得到优化，它们对心脏成像的益处也没有得到严格的测试。在这笔赠款中，我们建议使用新颖、最先进的基于任务的图像质量测量方法和经过临床研究校准的真实且经过充分验证的模拟来对仪器、采集、重建和补偿参数和方法进行全面的端到端优化。我们将研究这些因素与获取时间/注射剂量之间的权衡，使医生能够用图像质量来换取更低的辐射剂量。这些结果将对提高图像质量、诊断准确性和减少患者剂量产生立竿见影的影响，同时还将通过指导未来SPECT系统的发展产生更长期的影响。这项工作还将使用投影域理想观察器来验证新的优化策略，这些观察器处理重建中使用的成像模型和真实成像过程之间的不匹配。

DESCRIPTION (provided by applicant): Single-Photon Emission Computed Tomography plays an important and well- validated role in the diagnosis and staging of a number of important cardiac diseases, and is widely used and available at many clinical sites in the US and around the world. The most common application has been myocardial perfusion SPECT to evaluate cardiovascular disease. A new and potentially important application is I-123 MIBG SPECT (AdreView) for myocardial innervation imaging. While there has been a great deal of work to develop improved reconstruction methods, and some work to develop optimized instrumentation and acquisition parameters, these have been done largely in isolation of each other. Questions such as: what is the optimal collimator when using collimator response compensation? what is the optimal energy window with scatter compensation?, is it optimal to use the same acquisition time for each projection view?, and is it optimal to use the same acquisition time per patient? have never been addressed. In addition, there are currently a number of dedicated scanners for cardiac imaging that incorporate several novel features to decrease acquisition time. Some of these are based on cadmium zinc telluride semiconductor detectors that provide improved full-width at half maximum energy resolution, but have a more complicated energy response that includes tails extending to low-energies. Other new detector materials such as LaBr with improved energy resolutions are on the horizon. However, energy windows and scatter compensation methods for CZT and LaBr detectors have not been optimized, nor has their benefit on cardiac imaging been rigorously tested. In this grant we propose to use novel, state-of-the art task-based image quality measures and realistic well-validated simulations calibrated by clinical studies to perform comprehensive end-to-end optimization of instrumentation, acquisition, reconstruction, and compensation parameters and methods. We will investigate the tradeoff between these factors and acquisition time/injected dose, allowing physicians to trade image quality for reduced radiation dose. The results would have an immediate impact in providing improved image quality, diagnostic accuracy, and reduced patient dose, while also having a longer term impact by guiding the development of future SPECT systems. The work will also provide validation of novel optimization strategies using projection-domain ideal-observers that handle mismatch between the imaging model used in the reconstruction and the true imaging process.