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

描述（由申请人提供）：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起着重要的作用，并且在美国和世界各地的许多临床场所广泛使用和可用。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）心肌神经成像。虽然在开发改进的重建方法和开发优化的仪器和采集参数方面已经做了大量的工作，但这些工作在很大程度上是相互孤立的。诸如：当使用准直器响应补偿时，最佳准直器是什么？带散射补偿的最优能量窗是什么？对于每个投影视图使用相同的获取时间是否最优？，每位患者使用相同的获取时间是否最佳？从未被提及。此外，目前有许多用于心脏成像的专用扫描仪，它们结合了一些新颖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，在最大能量分辨率的一半下提供改进的全宽度，但具有更复杂的能量响应，包括延伸到低能量的尾巴。其他新的探测器材料，如提高能量分辨率的LaBr也即将问世。然而，用于CZT和LaBr探测器的能量窗和散射补偿方法还没有得到优化，它们对心脏成像的好处也没有得到严格的测试。在这项拨款中，我们建议使用新颖的，最先进的基于任务的图像质量测量和现实的经过临床研究校准的经过验证的模拟，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采集时间/注射剂量之间的权衡，使医生能够以图像质量为代价降低辐射剂量。研究结果将在提高图像质量、诊断准确性和减少患者剂量方面产生直接影响，同时通过指导未来SPECT系统的发展也会产生长期影响。这项工作还将提供新的优化策略的验证，该策略使用投影域理想观察者来处理重建中使用的成像模型与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.