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。在之前的项目期间，我们专注于对散射、衰减和距离相关的空间分辨率进行校正的方法的优化，以及对脑深部结构成像的采集策略的优化。在这一更新应用中，我们将注意力转向同步双同位素成像、分析和迭代图像处理和重建的比较，以及在上一个项目期间为专用大脑系统开发的推广准直进展的领域，以更普遍地使用双头系统。我们的方法包括分析、模拟、体模实验和病人研究。分析和模拟研究，虽然属于原型估计和分类任务，但将纳入真实的解剖学和生物变异性。我们将继续开发特殊用途的准直器，它对投影进行不均匀的采样，以便通过衰减来补偿中央大脑结构的信息损失。我们将制造一个这样的准直器，在最后一个项目期间为专用的脑SPECT系统设计。我们将为双头SPECT系统设计一个类似的准直器，使用计算机模拟解剖逼真的数字体模，优化其性能，以完成与帕金森病相关的定量脑成像任务。我们还将确定同时进行双能量显像时的活动性估计的理论极限，并评估双核素显像在与胶质母细胞瘤和成人注意缺陷多动障碍相关的临床任务中的价值。我们将比较在原型估计任务以及与阿尔茨海默病相关的临床任务中，用于校正衰减和距离依赖分辨率的分析方法与包含在迭代重建算法中的校正。

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.