Physical Limits of Quantitative SPECT

该项目的长期目标是开发基于定量成像任务的指标，并使用它们来确定定量SPECT的基本限制。在上一个项目期间，我们专注于优化方法，以校正散射，衰减和距离相关的空间分辨率，以及优化成像深部脑结构的采集策略。在此更新应用中，我们将注意力转向同步双同位素成像领域，分析和迭代图像处理和重建的比较，以及在专用脑系统的最后一个项目期间开发的准直进展，更常见的双头系统。我们的方法包括分析，模拟，幻影实验和病人的研究。分析和模拟研究，虽然属于原型估计和分类任务，将结合现实的解剖和生物变异性。我们将继续研制特殊用途的准直仪，它对投影进行不均匀采样，以补偿由于衰减而造成的中枢脑结构信息的损失。我们将在最后一个项目期间制造一个这样的准直器，用于专用的脑SPECT系统。我们将设计一个类似的准直器的双头SPECT系统，优化其性能的定量脑成像任务，相关的帕金森病，使用计算机模拟的解剖逼真的数字幻影。我们还将确定Tc/I和Tc/TI同时双能量成像中活动估计的理论限制，并评估双同位素成像在胶质母细胞瘤和成人注意缺陷多动障碍相关临床任务中的价值。我们将比较分析方法，以纠正衰减和距离相关的分辨率，以纠正纳入迭代重建算法中的原型估计任务，以及与阿尔茨海默病相关的临床任务。

The long-term goal of this project is to develop quantitative imaging task based metrics and, using them, determine the fundamental limits on quantitative SPECT. In the previous project period, we focused on optimization of methods to correct for scatter, attenuation, and distance- dependent spatial resolution, as well as optimizing the acquisition strategy for imaging deep brain structures. In this renewal application, we turn our attention to the areas of simultaneous dual-isotope imaging, comparison of analytical and iterative image processing and reconstruction and on generalizing collimation advances, developed during the last project period for a dedicated brain system, to more commonly available dual-head systems. Our approaches include analysis, simulation, phantom experiments and patient studies. The analyses and simulation studies, although pertaining to prototypical estimation and classification tasks, will incorporate realistic anatomy and biological variability. We will continue the development of special-purpose collimators which sample the projections unequally in order to compensate for loss of information from central brain structures by attenuation. We will manufacture one such collimator, designed for a dedicated brain SPECT system during the last project period. We will design a similar collimator for a dual-head SPECT system, optimizing its performance for quantitative brain imaging tasks, relevant to Parkinson disease, using computer simulations of an anatomically realistic digital phantom. We will also determine the theoretical limits on activity estimation in simultaneous dual-energy imaging for both Tc/I and Tc/TI, and assess the value of dual-isotope imaging in clinical tasks related to glioblastoma and adult attention deficit hyperactivity disorder. We will compare analytical methods to correct for attenuation and distance dependent resolution to corrections incorporated into an iterative reconstruction algorithm in prototypical estimation tasks, as well as clinical tasks relevant to Alzheimer disease.