A new direction to achieve ultra-fast timing for positron emission tomography

实现正电子发射断层扫描超快定时的新方向

• 批准号: 9444922
• 负责人: CRAIG S LEVIN
• 金额: $ 64.71万
• 依托单位: STANFORD UNIVERSITY
• 依托单位国家: 美国
• 财政年份: 2017
• 资助国家: 美国
• 起止时间: 2017-09-30 至 2021-06-30
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/9444922
• 关键词: Biodistribution; Charge; Clinic; Clinical Management; Clinical Research; Collection; Contrast Media; Crystallization; Detection; Disease; Disease Management; Dose; Elements; Enhancing Lesion; Event; Generations; Genetic Recombination; Goals; Image; Imagery; Imaging technology; Individual; Industry; Injectable; Ionizing radiation; Ions; Label; Lasers; Learning; Lesion; Light; Lutetium; Methods; Modernization; Molecular Profiling; Monitor; Nature; Noise; Operating System; Optics; Patients; Performance; Phase; Photons; Physiologic pulse; Positron; Positron-Emission Tomography; Predisposition; Process; Production; Property; Pump; Radiation; Radioisotopes; Refractive Indices; Research; Resolution; Roentgen Rays; Role; Scanning; Signal Transduction; Source; Speed; System; Telecommunications; Three-Dimensional Image; Time; Tracer; Width; Work; base; biological research; cost effective; design; detector; electric field; improved; ionization; migration; multidisciplinary; non-invasive imaging; novel; optical switch; photon-counting detector; scale up; temporal measurement; two-photon

PROJECT SUMMARY/ABSTRACT We propose to explore a new mechanism of ionizing radiation detection for positron emission tomography (PET) using the modulation of optical properties instead of scintillation, with the ultimate goal to achieve less than 10 picosecond (ps) annihilation photon pair coincidence time resolution, which is an order of magnitude better than possible with state-of-the-art scintillation based PET detectors. PET is a non-invasive imaging technology used every day throughout the world that enables visualization and quantification of the molecular signatures of disease in living subjects in the clinic as well as in biological research. A PET study comprises the collection of millions of annihilation photon pairs emitted from a positron-emitting radionuclide-labeled contrast agent injected into the patient. The two-photon hits are recorded by the system detectors and used to reconstruct a 3D image volume that represents the tracer biodistribution. If successful, the proposed < 10 ps coincidence time resolution would represent a tremendous paradigm shift for PET as it would drastically change the way a PET system operates. The resulting remarkable time-of-flight (ToF) capability will bring substantial signal amplification over existing systems. The enormous image signal-to-noise ratio (SNR) boost can be exploited to greatly enhance lesion detection, for example, for lesions with low contrast-to-background ratio; significantly reduce both patient injected dose and patient scan duration, potentially opening new clinical and research roles for which PET currently has no involvement at all; or pave the way for completely new PET system designs with greatly improved spatial resolution. In previous studies performed, we have shown that ionizing radiation can modulate optical properties, for example, the refractive index, of a detector material. We have found that the modulation signal amplitude is linearly dependent on both the event detection rate and average photon energy. In this project, we will work on further exploring mechanisms of optical property modulation to detect individual 511 keV photon interactions, and study the timing properties of this proposed detection concept with the goal to achieve < 10 ps coincidence time resolution. We first propose to achieve the detection of individual 511 keV photons using the mechanism of optical property modulation by developing novel methods to amplify the modulation signal and detection systems with significantly improved sensitivity. Then we plan to study the intrinsic timing properties of the optical property modulation process and explore methods to achieve < 10 ps coincidence time resolution for coincident 511 keV photon interactions. For the final aim, we will learn how to use this new mechanism of ionizing radiation detection to build a practical, “tileable” ToF-PET detection element. This is an exciting multi-disciplinary project that borrows ideas from the field of modern optics with a goal of enabling substantial improvements in ToF-PET performance to drive important advances in the study and clinical management of disease.

项目总结/摘要 我们提出探索一种新的正电子发射断层扫描电离辐射探测机制 (PET)利用光学特性的调制代替闪烁，最终目的是实现更少的 小于10皮秒（ps）湮灭光子对符合时间分辨率，这是一个数量级 比最先进的基于闪烁的PET探测器更好。 PET是一种非侵入性成像技术，每天在世界各地使用，可以实现可视化 以及在临床和生物学中对活体受试者中疾病的分子特征进行定量 research. PET研究包括收集从一个光子发射的数百万个湮灭光子对。 注射到患者体内的正电子发射放射性核素标记的造影剂。双光子撞击被记录下来 并用于重建代表示踪剂生物分布的3D图像体积。 如果成功，所提出的< 10 ps符合时间分辨率将代表一个巨大的范例 这将极大地改变PET系统的运行方式。由此产生的非凡的 飞行时间（ToF）能力将在现有系统上带来显著的信号放大。的巨大 可以利用图像信噪比（SNR）提升来极大地增强病变检测，例如， 对比度与背景比低的病变;显著降低患者注射剂量和患者扫描 持续时间，可能会开辟新的临床和研究角色，PET目前根本没有参与; 或者为具有大大改进的空间分辨率的全新PET系统设计铺平道路。 在以前的研究中，我们已经表明，电离辐射可以调制光学性质， 例如，检测器材料的折射率。我们已经发现，调制信号幅度是 线性依赖于事件检测率和平均光子能量。在这个项目中，我们将致力于 进一步探索光学性质调制的机制以检测单独的511 keV光子相互作用， 并研究了所提出的探测概念的定时特性，目标是实现< 10 ps的重合 时间分辨率我们首先提出使用以下机制来实现单个511 keV光子的探测： 通过开发新的方法来放大调制信号和检测光学特性调制 系统的灵敏度大大提高。然后，我们计划研究光的内在定时特性， 特性调制过程，并探索实现符合时间分辨率< 10 ps的方法， 511 keV光子相互作用。为了最终的目的，我们将学习如何使用这种新的电离辐射机制 ToF-PET探测器是一种实用的、“可拼接”的ToF-PET探测元件。这是一个令人兴奋的多学科项目 该技术借鉴了现代光学领域的思想，目标是实现ToF-PET的实质性改进。 性能，以推动疾病的研究和临床管理的重要进展。