Physical limits of quantitative ECT

描述(申请人提供)：在这份续签申请中，我们继续调查定量SPECT成像的基本限制，并将我们的范围扩大到包括PET。我们完成了脑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：为系统评估开发基于任务的量化指标，并使用这些指标来量化ECT成像系统改进的价值。在拟议的项目期内，我们将把重点放在成像系统最基本的方面--数据采集，这决定了量化的最终限度。我们将根据与阿尔茨海默病、帕金森病和心血管疾病相关的评估任务的性能来评估最近三种硬件进步的优点。大脑和心脏硬件的改进预计将在不影响空间分辨率的情况下，在灵敏度方面分别提供约一个数量级的改进。同样，将TOF信息添加到PET成像中有望在图像质量方面提供实质性的提高。在相对成熟的医学成像领域中，发现承诺提供如此重大改进的新硬件修改是极其罕见的。在拟议的研究中，我们将量化定量脑和心脏成像在评估任务绩效方面预期的收益，这三个进步中的一个出现在前一个项目期间。我们将制造一个在前一个项目期间设计的准直器，预计将使脑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。将考虑一系列临床现实的噪声水平，包括我们先前已经证明不可能有效估计非线性参数的噪声水平。

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.