Energy-based image reconstruction for new generation PET

描述（由申请人提供）：该项目是提高正电子发射断层扫描（PET）获得的图像质量的长期努力的一部分，PET已成为诊断放射学和核医学中断层成像的重要技术。该项目涉及从PET扫描仪的基本探测器数据生成图像的计算机方法，包括补偿数据的非理想特性的处理操作，以及从初始处理产生的投影数据重建图像的算法。利用本PET扫描器和用于处理数据的方法，发现针对大体型患者获得的图像的质量比针对正常体型患者的图像的质量低得多，因为与来自正常体型患者的数据相比，来自大体型患者的PET扫描的数据集包含较大比例的散射光子和较小比例的未散射光子。该项目的目的是通过使用新的数据处理方法来改善PET中获得的图像，这些方法利用了未散射光子和散射光子的能量分布之间的显著差异。新的基于能量的方法将利用现代扫描仪更好的能量分辨率，并将能够充分利用下一代闪烁晶体和探测器的出色能量分辨率和定时。所提出的方法是通用的，并且可以以比目前使用的基于图像的散射估计方法更简单的方式应用于当前常规PET扫描仪。它们还将被设计用于新一代的飞行时间PET（TOF-PET）扫描仪的需要，对于这种扫描仪，还没有开发出足够的散射校正技术。该方法旨在开发、实施、测试和评估基于能量的PET和TOF-PET新方法的可行性，这些方法涉及组合图像重建和散射估计。这些方法将与最广泛使用的传统方法，这是单散射模拟方法的扩展进行比较。比较研究将使用模拟数据和使用来自物理测试体模的实验PET数据进行。新的基于能量的方法有可能显著提高PET图像中放射性示踪剂摄取的逐体素估计的准确性，这将导致PET临床应用的改进，例如癌症的PET成像，这反过来将对公共健康产生重大影响。

DESCRIPTION (provided by applicant): This project is part of a long-term effort to improve the quality of the images obtained by positron emission tomography (PET), which has become an important technique for tomographic imaging in diagnostic radiology and nuclear medicine. The project involves computer methods for generating images from the basic detector data of PET scanners, including processing operations to compensate for non-ideal characteristics of the data, and algorithms for image reconstruction from the projection data produced by the initial processing. With the present PET scanners and methods for processing the data, it is found that the images obtained for large patients are of much lower quality than the images for normal-sized patients, because the data set from a PET scan of a large patient contains a larger proportion of scattered photons and a smaller proportion of unscattered photons, compared to the data from a normal-sized patient. The aim of this project is to improve the images obtained in PET through the use of new methods of processing the data that exploit the marked difference between the energy distributions of unscattered and scattered photons. The new energy-based methods will take advantage of the better energy resolution of modern scanners and will enable full use of the excellent energy resolution and timing of the next generation of scintillation crystals and detectors. The methods proposed are general and can be applied to the current conventional PET scanners in a simpler manner than the presently used image based scatter estimation methods. They will also be designed for the needs of the new generation of scanners for time-of-flight PET (TOF-PET), for which adequate scatter correction techniques have not yet been developed. The approach is to develop, implement, test, and evaluate for feasibility, new energy-based methods for PET and TOF-PET involving combined image reconstruction and scatter estimation. These methods will be compared with extensions of the most widely used conventional method, which is the single-scatter- simulation method. The comparison studies will be done using simulated data and using experimental PET data from physical test phantoms. New energy-based methods have the potential to significantly improve the accuracy of the voxel-by-voxel estimates of radiotracer uptake in PET images, which would lead to improvements in the clinical applications of PET, such as PET imaging of cancer, which would in turn have a significant impact on public health.