Prism-PET: A TOF-DOI-Compton PET detector technology for total-body PET imaging

Prism-PET：用于全身 PET 成像的 TOF-DOI-康普顿 PET 探测器技术

• 批准号: 10394381
• 负责人: Amirhossein Goldan
• 金额: $ 61.63万
• 依托单位: STATE UNIVERSITY NEW YORK STONY BROOK
• 依托单位国家: 美国
• 财政年份: 2021
• 资助国家: 美国
• 起止时间: 2021-05-01 至 2022-12-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/10394381
• 关键词: Architecture; Behavior; Brain; Caliber; Calibration; Collaborations; Compton radiation; Computer software; Coupled; Coupling; Crystallization; Custom; Data; Detection; Dose; Electronics; Elements; Event; Floods; Geometry; Goals; Hot Spot; Human; Image; Imaging Phantoms; Industrialization; Length; Light; Location; Machine Learning; Modeling; Monte Carlo Method; Noise; Optics; Organ; PET/CT scan; Pattern; Penetration; Performance; Photons; Positron-Emission Tomography; Process; Radiation Tolerance; Recovery; Research; Resolution; Rotation; Scanning; Signal Transduction; Silicon; Source; Supervision; System; Technology; Temperature; Testing; Time; Training; Universities; Variant; Vision; Work; convolutional neural network; cost; cost effective; detector; image reconstruction; improved; novel; performance tests; photomultiplier; prototype; reconstruction; response; risk mitigation; simulation

Abstract The relatively small axial field-of-view (FOV) in almost all PET scanners has severely limited their sensitivity and resulted in significant tradeoffs between image signal-to-noise ratio (SNR), acquisition time, and delivered dose. The solution is to improve geometric coverage using large axial FOV for total-body imaging which has the potential to improve sensitivity by about 40 times compared to existing commercial whole-body PET scanners. The construction of the world's first total-body PET/CT scan-ner, called EXPLORER, with 194-cm axial FOV has recently been completed. However, it has a poor time-of-flight (TOF) resolution of 430 ps, compared to the state-of-the-art whole-body PET scanner with 200 ps timing resolution (Siemens Biograph Vision). In addition, axial detector penetration of obliquely incident gamma photons detected within this wide acceptance angle will introduce significant depth-of-interaction (DOI) parallax error, leading to degraded spatial resolution. These two major defi-ciencies of the EXPLORER scanner offset its effective sensitivity gain, specially for imaging single organs such as the human brain when compared to the Biograph Vision PET scanner. For this research, we propose to build cost-effective block detectors with combined highest spatial resolution (2 mm), highest TOF resolution (<120 ps and potentially 100 ps), best DOI localization (1.85 mm), and highest inter- crystal Compton scatter recovery capabilities (88%) using single-ended readout and machine learning post-processing engines. Our novel detector module, called Prism-PET, enables these capabilities by mimicking very closely the behavior of dual-ended readout with enhanced and controlled light sharing using a segmented array of right angle prism-mirror light guides. Given our promising preliminary ex-perimental results, we aim to accomplish the following tasks: (1) model a prototype TOF-DOI PET scanner using GATE Monte Carlo simulations and use its list-mode data to develop our TOF-DOI image recontruction; (2) build Prism-PET detector modules and characterize coincidence detector blocks for DOI-corrected spatial resolution, energy resolution, and timing resolution and use machine learning to recover inter-crystal Compton scattered events to reach the 2-mm intrinsic spatial resolution without sacrificing sensitivity; (3) Build a one-ring prototype Prism-PET scanner; (4) perform normalization scan, optimize our image reconstruction using experimental coincidence events and validate the optimal imaging performance using Hot Spot phantoms. Our proposed TOF-DOI-Compton detector and system technologies maximize the sensitivity benefits of improved geometric coverage in total-body PET scanners across the entire FOV.

抽象的 几乎所有 PET 扫描仪的轴向视场 (FOV) 相对较小，严重限制了其灵敏度，并导致图像信噪比 (SNR)、采集时间和输送剂量之间存在重大权衡。该解决方案是使用大轴向 FOV 进行全身成像来提高几何覆盖范围，与现有的商用全身 PET 扫描仪相比，这有可能将灵敏度提高约 40 倍。世界上第一台全身 PET/CT 扫描仪 EXPLORER 的建造最近已完成，该扫描仪具有 194 厘米的轴向 FOV。然而，与具有 200 ps 定时分辨率的最先进的全身 PET 扫描仪（Siemens Biograph Vision）相比，它的飞行时间 (TOF) 分辨率较差，仅为 430 ps。此外，在如此宽的接收角内检测到的倾斜入射伽马光子的轴向探测器穿透将引入显着的交互深度（DOI）视差误差，导致空间分辨率下降。与 Biograph Vision PET 扫描仪相比，EXPLORER 扫描仪的这两个主要缺陷抵消了其有效的灵敏度增益，特别是对于人脑等单个器官的成像。对于这项研究，我们建议构建具有成本效益的块探测器，结合最高空间分辨率（2毫米）、最高TOF分辨率（<120 ps，可能为100 ps）、最佳DOI定位（1.85毫米）和最高晶间康普顿使用单端读出和机器学习后处理引擎的散射恢复能力（88%）。我们的新型探测器模块称为 Prism-PET，通过使用分段的直角棱镜镜光导阵列来非常接近地模仿双端读出的行为，并增强和控制光共享，从而实现这些功能。鉴于我们有希望的初步实验结果，我们的目标是完成以下任务：（1）使用 GATE Monte Carlo 模拟对原型 TOF-DOI PET 扫描仪进行建模，并使用其列表模式数据来开发我们的 TOF-DOI 图像重建； (2) 构建 Prism-PET 探测器模块并表征重合探测器块的 DOI 校正空间分辨率、能量分辨率和定时分辨率，并使用机器学习恢复晶间康普顿散射事件，以在不牺牲内部空间分辨率的情况下达到 2 毫米固有空间分辨率敏感性； (3)搭建一环原型Prism-PET扫描仪； (4) 执行归一化扫描，使用实验重合事件优化图像重建，并使用热点模型验证最佳成像性能。我们提出的 TOF-DOI-Compton 探测器和系统技术最大限度地提高了全身 PET 扫描仪在整个视场内的几何覆盖范围的灵敏度优势。