Physical limits of quantitative ECT

描述（由申请人提供）：在这份更新申请中，我们继续研究定量SPECT成像的基本限制，并将我们的范围扩大到PET。我们完成了在脑SPECT成像专用准直领域的工作，并在心脏SPECT成像和PET飞行时间（TOF）成像领域增加了新的重点。我们的目标仍然是双重的：开发基于定量任务的系统评估指标，并使用这些指标来量化改进ECT成像系统的价值。在拟议的项目期间，我们将重点关注成像系统最基本的方面，数据采集，这决定了量化的最终限制。我们将评估最近三种硬件进展的优点，即在与阿尔茨海默病、帕金森病和心血管疾病相关的估计任务中的性能。大脑和心脏硬件的改进有望在不影响空间分辨率的情况下提供大约一个数量级的灵敏度提高。同样，将TOF信息添加到PET成像中也有望大幅提高图像质量。在相对成熟的医学成像领域，发现新的硬件修改承诺提供如此显著的改进是极其罕见的。在拟议的研究中，我们将量化从这三个进展中预期的定量脑和心脏成像在估计任务性能方面的收益，其中一个来自上一个项目时期。我们将制造一个准直器，在上一个项目期间设计，预计将脑部SPECT的灵敏度平均提高10倍。我们还将评估高灵敏度专用心脏SPECT系统的性能，并量化PET TOF信息在脑和心脏应用中的优势。活性浓度和动力学参数估计的偏差和精度将通过分析、模拟和实验来确定。将考虑一系列临床实际的噪声水平，包括我们以前表明的非线性参数的有效估计是不可能的噪声水平。

DESCRIPTION (provided by applicant): In this renewal application, we continue our investigation of the fundamental limits on quantitative SPECT imaging and expand our scope to include PET. We complete our efforts in the area of special purpose collimation for brain SPECT imaging, and add new emphases in the areas of cardiac SPECT imaging and PET time-of-flight (TOF) imaging. Our goals remain two-fold: to develop quantitative task based metrics for system assessment, and to use these metrics to quantify the value of improvements to ECT imaging systems. In the proposed project period, we will focus on the most fundamental aspect of the imaging system, data acquisition, which determines the ultimate limits on quantitation. We will assess the merits of three recent hardware advances in terms of performance in estimation tasks related to Alzheimer disease, Parkinson disease, and cardiovascular disease. The brain and cardiac hardware improvements are each expected to provide about an order of magnitude improvement in sensitivity without compromising spatial resolution. Similarly, the addition of TOF information to PET imaging promises to provide substantial gains in image quality. It is extremely uncommon in relatively mature fields of medical imaging to discover new hardware modifications which promise to provide such a significant improvement. In the proposed research we will quantify the gains in estimation task performance to be expected for quantitative brain and cardiac imaging from these three advances, one of which emerged from the previous project period. We will manufacture a collimator, designed during the previous project period, which is expected to increase sensitivity of brain SPECT by, on average, a factor of 10. We will also assess the performance of a high-sensitivity dedicated cardiac SPECT system, and quantify the advantages of PET TOF information for both brain and cardiac applications. Bias and precision of estimates of activity concentration and kinetic parameters will be determined by analysis, simulation, and experiment. A range of clinically realistic noise levels will be considered, including noise levels at which we have previously shown that efficient estimation of nonlinear parameters is not possible.