Reconstruction-free three dimensional positron emission imaging

免重建三维正电子发射成像

• 批准号: 10504837
• 负责人: Sun Il Kwon
• 金额: $ 55.66万
• 依托单位: UNIVERSITY OF CALIFORNIA AT DAVIS
• 依托单位国家: 美国
• 财政年份: 2022
• 资助国家: 美国
• 起止时间: 2022-09-01 至 2026-06-30
• 项目状态: 未结题
• 来源: https://reporter.nih.gov/project-details/10504837
• 关键词: 3-Dimensional; Algorithms; Anodes; Area; Biomedical Research; Cherenkov Radiation; Clinical; Complement; Computational algorithm; Data; Data Collection; Detection; Development; Diagnostic Neoplasm Staging; Discrimination; Disease; Event; Excision; Eye; Foundations; Fruit; Future; Generations; Glass; Goals; Health; Hospitals; Image; Imaging Device; Lead; Light; Location; Machine Learning; Measures; Monte Carlo Method; Nature; Noise; Optics; Outcome; Patients; Performance; Photons; Physics; Positioning Attribute; Positron; Positron-Emission Tomography; Process; Property; Radiation Dose Unit; Radioisotopes; Reaction Time; Refractive Indices; Resolution; Sampling; Scanning; Series; Signal Transduction; System; Techniques; Three-Dimensional Image; Three-Dimensional Imaging; Time; Translations; Tube; Vision; Weight; Work; base; breast imaging; clinical application; clinical imaging; clinical translation; convolutional neural network; deep learning; design; detection sensitivity; detector; flexibility; heart imaging; human imaging; image reconstruction; imaging platform; imaging system; improved; innovation; instrumentation; machine learning algorithm; novel; personalized care; photomultiplier; portability; preservation; prototype; radiotracer; real-time images; reconstruction; response; scale up; signal processing; simulation; tomography; tool; treatment response

Project Summary/Abstract A major advantage of coincidence detection of annihilation photons from positron-emitting radiotracers is the availability of time-of-flight (TOF) information, and the ability to measure TOF differences to better localize the positron emitter. Normally for positron emission tomography (PET), TOF information is used as a weighting kernel during image reconstruction and results in an effective sensitivity gain that can be used to reduce radiation dose, improve signal-to-noise ratio, or reduce scan duration. The magnitude of these benefits depend on the TOF resolution, which is governed by the timing performance of the detectors. Current state of the art for PET scanners is ~220 ps which corresponds to a localization of ~3.3 cm. A transformational change would occur, however, if a TOF resolution of <30 ps could be achieved. This would localize events within 4.5 mm, allowing images to be directly generated without a reconstruction algorithm at a spatial resolution that matches what is achieved in clinical PET scanners today. We refer to this as direct positron emission imaging (PEI). With this superb TOF resolution and reconstruction-free imaging, we enter a new regime where we expect major increases in image signal-to-noise, both due to the additional TOF information, and the removal of noise amplification inherent in reconstructing noisy data with noisy corrections from projection data. We propose to develop a first proof-of-concept imaging system that uses ultra-fast detectors to directly produces cross-sectional images without reconstruction and to quantify the performance of PEI both through simulations and experimentally. Since direct PEI does not have the same sampling constraints for data collection as PET, it creates opportunities for portable, and flexible imaging devices, with implications for patient-tailored or task-specific imaging applications (i.e. cardiac or breast imaging), as well as open designs for general purpose applications. To achieve the unprecedented TOF capabilities needed for direct PEI, we will exploit promptly emitted Cerenkov radiation that is generated with <10 ps in certain materials, including scintillators, in response to a 511 keV photon interaction. Our proposed novel detector design integrates a Cerenkov radiator directly into the entrance window of an ultra-fast microchannel plate photomultiplier tube, which is the fastest photon detector currently available with a response time of 25 ps. This approach eliminates all optical reflections between the point of light generation and the photocathode, preserving the prompt timing nature of Cerenkov photons. We then combine the integrated Cerenkov radiator detector with auxiliary photodetector read-out for robust coincidence detection, and complement this with advanced signal processing algorithms we have pioneered using convolutional neural networks to extract all possible timing information from the digitized detector waveforms and ultimately to perform reconstruction-free imaging using only the digitized waveforms as input. In summary, we aim to prove that direct PEI is possible, to characterize its properties and to provide the technological and algorithmic foundations for eventual translation for human imaging.

项目摘要/摘要 从正电子发射放射性示例中检测到an灭光子的巧合的主要优势是 飞行时间（TOF）信息的可用性以及测量TOF差异以更好地本地化的能力 正电子发射极。通常，对于正电子发射断层扫描（PET），TOF信息用作加权 图像重建过程中的内核，并产生有效的灵敏度增益，可用于减少辐射 剂量，提高信噪比或减少扫描持续时间。这些好处的大小取决于 TOF分辨率，该分辨率受探测器的定时性能约束。当前的宠物艺术状态 扫描仪为〜220 ps，对应于〜3.3 cm的定位。会发生变革的变化， 但是，如果可以实现<30 ps的TOF分辨率。这将在4.5毫米内定位事件，允许 在没有重建算法的情况下直接生成的图像在与什么匹配的空间分辨率下 今天在临床PET扫描仪中实现。我们将其称为直接正电子发射成像（PEI）。与此 出色的TOF分辨率和无重建成像，我们进入了一个新的制度，我们期望重大增加 在图像到信号到噪声中，由于额外的TOF信息和噪声放大的去除 从投影数据中重建嘈杂的数据，固有的嘈杂数据。我们建议开发第一个 概念验证成像系统，该系统使用超快速探测器直接产生横截面图像 没有重建并通过模拟和实验来量化PEI的性能。 由于直接PEI对数据收集的采样限制与宠物没有相同的采样限制，因此它创造了机会 对于便携式和灵活的成像设备，对患者定制或特定任务的成像有影响 应用（即心脏或乳房成像）以及用于通用应用的开放设计。 为了达到直接PEI所需的前所未有的TOF功能，我们将迅速发出Cerenkov 响应511 keV的某些材料（包括闪烁体）在包括闪烁体的某​​些材料中产生的辐射 光子相互作用。我们提出的新型探测器设计将Cerenkov散热器直接集成到入口处 超快速的微通道板光电倍增管的窗户，这是当前最快的光子检测器 响应时间为25 ps。这种方法消除了光点之间的所有光学反射 生成和光电阴道，保留了Cerenkov光子的及时定时性质。然后我们结合了 具有辅助光电探测器的综合cerenkov散热器探测器读取了可靠的巧合检测， 并使用高级信号处理算法进行补充，我们使用卷积神经率先进行了启示 网络以从数字化检测器波形中提取所有可能的时序信息，并最终执行 仅使用数字化波形作为输入的无重构成像。总而言之，我们旨在证明这一点 PEI是可能的，以表征其特性并为技术和算法基础提供 人类成像的最终翻译。