ESTIMATION STRATEGIES FOR NUCLEAR MEDICAL IMAGING

这项研究的长期目标是开发体内的技术 放射性同位素在小动物体内定位的量化 加快并简化新的放射性标签的设计和评估 制药公司。 作为另一个项目的一部分，我们正在完成一个 模仿Sprint的高分辨率单光子环状断层扫描仪，但 专为99mTc、123I和131I在小鼠和大鼠体内的显像而设计 分辨率为毫米级。这项新提案的重点是发展 以及数据采集策略、下限和图像的评估 与以下特定任务目标相关的重建算法 最初是给小动物的： 1.整体器官或肿瘤摄取。 2.肿瘤和器官剂量分布。 将为这些项目制定性能限制和评估策略 任务既适用于有辅助信息可用的情况，例如 器官和肿瘤边界的准确估计的形式，以及在没有 这样的信息是可以获得的。与不受约束的图像任务不同 重建时，这些任务涉及的特定任务数量要少得多 要估计的参数，因此更好的估计器统计 稳定是可以预期的。对这些参数的估计最初将 从使用约束E-M重建的完整图像计算得到 广义Landweber迭代算法。基于投影数据的LOWER 最小可达估计器均方误差的界将用于 优化数据采集以在以下各项之间提供最佳平衡 准直器分辨率和灵敏度与准直器性能相关 具体的测算任务。

The long term aim of this research is to develop techniques for in vivo quantification of radioisotope localization in small animals in order to speed and simplify the design and evaluation of new radiolabeled pharmaceuticals. As part of another project we are completing construction of a high-resolution single photon ring tomograph modeled after SPRINT, but specifically designed for imaging 99mTc, 123I, and 131I in mice and rats with millimeter resolution. The focus of this new proposal is development and evaluation of data acquisition strategies, lower bounds, and image reconstruction algorithms for the following taskspecific objectives related initially to small animals: 1. Total organ or tumor uptake. 2. Tumor and organ dose distribution. Performance limits and estimation strategies will be developed for these tasks both for the case where there is side information available, e.g. in the form of accurate estimates of organ and tumor boundaries, and where no such information is available. Unlike the task of unconstrained image reconstruction, these tasks involve a much smaller number of task-specific parameters to be estimated and therefore better estimator statistical stability can be expected. Estimates of these parameters will initially be calculated from complete images reconstructed using constrained E-M and generalized Landweber iterative algorithms. Projection-data based lower bounds on minimum achievable estimator mean-square- error will be used to optimize data acquisition so as to provide the best tradeoff between collimator resolution and sensitivity relative to the performance of a specific estimation task.