Exploring the Benefits of Time-of-Flight PET

描述（由申请人提供）：简单的理论预测，通过使用飞行时间（TOP）信息，PET研究中的成像时间或注射剂量可以减少大约一个数量级。这种减少可以通过提高符合时间分辨率来实现，因此可以在临床，全身研究中使用PET系统，与现有摄像机相差不大。本提案的目的是在原型PET相机中实现最佳的时序分辨率，并通过实验验证性能改进，测量改进对时序分辨率的依赖程度。这一发展的潜在影响是巨大的，特别是对于大患者的肿瘤学研究，这是迫切需要的。飞行时间PET在20世纪80年代得到了广泛的研究，但在20世纪90年代夭折了，因为在不牺牲其他PET性能方面的情况下，不可能可靠地获得足够好的定时分辨率。最近技术的进步重新引起了人们对TOP PET的兴趣，但在过去十年中，PET的技术和医疗用途的变化意味着TOP在现代临床PET中的真正好处还没有得到很好的理解。通过将这些好处量化为定时分辨率的函数，我们将指导未来的商业和学术顶级PET相机设计师，让他们做出明智的选择。为了实现这一目标，我们将构建一个带有LSO闪烁晶体的单环“演示”PET相机，达到300 ps的符合时间分辨率。这比任何基于lso的PET相机的时间分辨率都要高两倍，而且简单的估计预测，它将在全身成像中减少8倍的噪声方差。在临床上，这种方差的减少可以减少图像噪声，减少注射剂量，缩短成像时间，或提供这些好处的组合。我们将使用模拟、模拟和人体受试者研究的组合，包括肿瘤检测和分期的临床相关任务，将噪声的改善量化为时间分辨率的函数。然后，我们将用新开发的闪烁体（Lul3:Ce）重建相机，该闪烁体具有优异的PET性能（高灵敏度，3%能量分辨率和125 ps定时分辨率），并重复这些测量。这个定时分辨率比任何曾经建造或提出的TOP相机都要好三倍以上，并且预计会大大降低（18倍）噪声方差。

DESCRIPTION (provided by applicant): Simple theory predicts that the imaging time or injected dose in a PET study can be reduced by roughly an order of magnitude by using time-of-flight (TOP) information. This reduction can be obtained by improving the coincidence timing resolution, and so would be achievable in clinical, whole body studies using with PET systems that differ little from existing cameras. The purpose of this proposal is to realize the best possible timing resolution in a prototype PET camera and verify the performance improvement experimentally, measuring how the improvement depends on the timing resolution. The potential impact of this development is large, especially for oncology studies in large patients, where it is sorely needed. Time-of-flight PET was extensively studied in the 1980's but died in the 1990's, as it was impossible to reliably achieve sufficiently good timing resolution without sacrificing other PET performance aspects. Recent improvements in technology have renewed interest in TOP PET, but changes in the last decade in both technology and the medical uses for PET mean that the true benefits of TOP in modern clinical PET are not well understood. By quantifying these benefits as a function of timing resolution, we will guide future commercial and academic TOP PET camera designers by allowing them to make informed choices. To realize this goal, we will construct a single ring "demonstration" PET camera with LSO scintillator crystals that achieves 300 ps coincidence timing resolution. This is a factor of two better timing resolution than any LSO-based PET camera ever constructed or currently proposed, and the simple estimates predict that it would reduce the noise variance by a factor of 8 in whole body imaging. Clinically, this variance reduction could reduce image noise, decrease the injected dose, shorten the imaging time, or provide a combination of these benefits. We will quantify the improvement in noise as a function of timing resolution using a combination of simulation, phantom, and human subject studies, including the clinically relevant tasks of tumor detection and staging. We will then rebuild the camera with a newly developed scintillator (Lul3:Ce) that has exceptional PET performance (high sensitivity, 3% energy resolution, and 125 ps timing resolution) and repeat these measurements. This timing resolution is over three times better than any TOP camera ever built or proposed, and is predicted to give an enormous (18-fold) noise variance reduction.