DIGITAL IMAGE REPRESENTATIONS FOR TOMOGRAPHIC RADIOLOGY

该提议针对改进X射线断层摄影成像， 诊断放射学和核医学。 据预测， 在图像的保真度方面将取得重大进展， 从原始探测器测量中重建的 断层扫描仪，并在体积的显示保真度， 从这些图像派生的表面，通过改变基本的类型， 元素（称为“基函数”），利用这些元素，图像被构建在 计算机，从传统的体素类型到最近开发的类型， 首席研究员 这些新的基本元素被本地化， 空间（体素基函数也是），但它们也有许多 体素基函数不共享的非常理想的性质（它们 旋转对称，它们的傅立叶变换有效地局部化， 它们具有任何所需阶数的连续导数， 从方便的公式计算，和他们的x射线变换有 类似的所需性质）。 由于这些特性，它们是理想的 形成生物结构的忠实数字图像表示 影响了原始断层扫描数据。 具体目标是发展数学理论、高效计算机 算法、特定于应用的实现和评估标准 对于（1）从投影迭代重建的方法，以及（2） 体积和表面的显示方法，使用最近开发的 基函数 这些目标的研究计划代表了一个重点3- 一年计划的基础上，计算机模拟和PET数据的现实 幻影 对于指定的成像任务，我们将评估 假设算法执行任务的水平 可以被拒绝，而支持另一种假设，即性能 一个的上级于另一个。 图像表示的基函数是基本核心 所有迭代重建方法和所有3D重建方法 显示，与成像模态无关（例如，CT、PET、SPECT、MRI）。 新的基函数和图像表示的发展将 充分发挥扫描仪在发射中的功能成像潜力 通过计算机算法实现的断层扫描（PET和SPECT） 结合了数据采集过程的真实模型。

This proposal is directed toward improving tomographic imaging in diagnostic radiology and nuclear medicine. It is predicted on the claim that significant advances will be achieved in the fidelity of the images that are reconstructed from the raw detector measurements of the tomographic scanner, and in the fidelity of the displays of volumes and surfaces that are derived from these images, by changing the type of basic elements (called "basis functions"), with which the image is built in the computer, from the conventional voxel type to a type recently developed by the Principal Investigator. These new basic elements are localized in space (as are the voxel basis functions) but they also have a number of very desirable properties not shared by voxel basis functions (they are rotationally symmetric, their Fourier transforms are effectively localized, they have continuous derivatives of any desired order and which can be calculated from convenient formulas, and their x-ray transforms have similar desirable properties). Due to these properties, they are ideal for forming faithful digital image representations of the biological structures that have influenced the raw tomographic scanner data. The specific aims are to develop mathematical theory, efficient computer algorithms, application-specific implementations and evaluation criteria for (1) methods of iterative reconstruction from projections, and (2) methods of display of volumes and surfaces, using the recently-developed basis functions. The research plans for these aims represent a focused 3- year program based on computer simulations and on PET data of realistic phantoms. For specified imaging tasks, we will evaluate the significance level at which the hypothesis that algorithms perform a task equally well can be rejected in favor of the alternative hypothesis that the performance of one is superior to that of another. The basis functions of the image representation are at the essential core of all methods for iterative reconstruction and of all methods for 3D display, irrespective of the imaging modality (e.g., CT, PET, SPECT, MRI). The development of new basis functions and image representations will enable the full potential of scanners for functional imaging in emission tomography (PET and SPECT) to be realized by means of computer algorithms that incorporate realistic models of the data acquisition process.