Utilization of Lutetium Background Radiation for Quantitative Total-Body PET Imaging

利用镥背景辐射进行定量全身 PET 成像

• 批准号: 10532720
• 负责人: Negar Omidvari
• 金额: $ 7.99万
• 依托单位: UNIVERSITY OF CALIFORNIA AT DAVIS
• 依托单位国家: 美国
• 财政年份: 2021
• 资助国家: 美国
• 起止时间: 2021-12-01 至 2024-11-30
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/10532720
• 关键词: Address; Adolescent; Adopted; Affect; Anatomy; Attention; Background Radiation; Beds; Body Regions; Cardiology; Child; Childhood; Clinical; Compensation; Data; Detection; Diagnosis; Discipline of Nuclear Medicine; Disease; Dose; Elements; Ensure; Event; Generations; Health; Human; Image; Infant; Inflammatory; Length; Lesion; Lutetium; Maps; Methodology; Methods; Monte Carlo Method; Motion; Neurology; Noise; Oncology; Patients; Photons; Population; Positioning Attribute; Positron-Emission Tomography; Process; Prognosis; Protocols documentation; Radiation Dose Unit; Research; Scanning; Signal Transduction; Source; Speed; System; Technology; Time; Translating; Vision; X-Ray Computed Tomography; attenuation; clinical application; data exchange; deep learning; denoising; detector; image reconstruction; image registration; improved; prevent; radiotracer; reconstruction; research study; tool; transmission process; treatment planning; trend; uptake

Project Summary/Abstract Positron emission tomography (PET) is widely used as a clinical and research tool for diagnosis, prognosis, and treatment planning in oncology, while increasingly being adopted in other fields such as cardiology, neurology, and inflammatory disorders. The latest generation of PET scanners offer significant enhancements in sensitivity with an increased axial imaging extent. The sensitivity gain in these scanners directly translates into improved image quality in standard imaging protocols and enables use of new scan protocols with ultrashort time frames or ultralow-dose scans. The long axial-field-of-view (AFOV) in these systems offers unique opportunities and challenges in addressing quantification barriers in PET. Among a wide range of factors affecting the quantitative accuracy of PET, the effects from attenuation, scatter, and human motion are common and predominant. In this project, we aim to utilize the lutetium (Lu) background radiation present in these scanners: first, for attenuation correction (AC) and scatter correction (SC), and second, for motion correction (MC), with particular attention on ultralow-dose PET scans. AC and SC are usually performed using the attenuation maps (μ-maps) obtained from a computed tomography (CT) scan performed prior to PET. As ultralow-dose PET scans are now made possible with long-AFOV PET scanners, it is desirable to further reduce the radiation dose by estimating the μ-maps from the Lu background radiation, when an additional CT scan can be avoided. We will primarily study our methodology with the uEXPLORER scanner, which is the world’s first total-body PET scanner that can simultaneously image the entire body, and will employ the Lu background data together with the PET emission data in maximum likelihood reconstruction of attenuation and activity (MLAA). We expect to achieve improved quantitative accuracy compared to prior studies as the high sensitivity and increased flux of background radiation originating from the large volume of Lu-based detectors in long-AFOV PET scanners, in addition to the ability of scanning the entire body in a single bed position, enables more efficient utilization of the Lu background. Finally, as human motion causes quantification bias by introducing image blurring and attenuation-emission mismatches, we will use a data-driven total-body MC framework to correct both the Lu-background-based μ-maps and the PET images. We will study the effects of different types of motion on PET quantification in two cases: first, when PET emission data is used for motion-estimation and second, feasibility of utilizing the Lu background data in motion-estimation, particularly in ultralow-dose scans or body regions with low radiotracer uptake, in which standard emission-based data-driven motion estimation methods are prone to error. This is especially important in total-body PET, as motion in one region of body could affect the AC and SC in other regions. We believe this contribution will improve the quantification and diagnosis capability in the new generation of PET scanners and will enable wider clinical and research applications of ultralow-dose PET, particularly in sensitive populations such as infants, children, and adolescents, leading to better understanding of human health.

项目概要/摘要 正电子发射断层扫描 (PET) 被广泛用作诊断、预后和诊断的临床和研究工具。 肿瘤学的治疗计划，同时越来越多地被应用于其他领域，如心脏病学、神经病学、 最新一代 PET 扫描仪的灵敏度显着提高。 随着轴向成像范围的增加，这些扫描仪的灵敏度增益直接转化为改进。 标准成像协议中的图像质量，并支持在超短时间范围内使用新的扫描协议 这些系统中的长轴向视野 (AFOV) 提供了独特的机会和机会。 解决 PET 定量障碍的挑战是影响定量的众多因素之一。 为了提高 PET 的准确性，衰减、散射和人体运动的影响在这方面很常见且占主导地位。 在该项目中，我们的目标是利用这些扫描仪中存在的镥 (Lu) 背景辐射：首先，用于衰减 校正（AC）和散射校正（SC），其次是运动校正（MC），特别注意 超低剂量 PET 扫描通常使用从以下位置获得的衰减图（μ 图）进行。 在 PET 之前进行计算机断层扫描 (CT)，因为现在可以进行超低剂量 PET 扫描。 对于长 AFOV PET 扫描仪，需要通过估计 μ 图来进一步减少辐射剂量 当可以避免额外的 CT 扫描时，我们将主要研究我们的 Lu 背景辐射。 uEXPLORER 扫描仪的方法，这是世界上第一台全身 PET 扫描仪，可以 同时对整个身体进行成像，并将 Lu 背景数据与 PET 发射一起使用 我们期望在衰减和活动的最大似然重建（MLAA）中实现数据的改进。 与之前的定量研究相比，由于灵敏度高且背景辐射通量增加，准确性更高 源于长 AFOV PET 扫描仪中大量基于 Lu 的探测器，除了能够 在单床位置扫描整个身体，可以更有效地利用 Lu 背景。 由于人体运动通过引入图像模糊和衰减发射不匹配而导致量化偏差， 我们将使用数据驱动的全身 MC 框架来校正基于 Lu 背景的 μ-map 和 我们将在两种情况下研究不同类型的运动对 PET 定量的影响：首先，当 PET 发射数据用于运动估计，其次是利用 Lu 背景数据的可行性 运动估计，特别是在超低剂量扫描或放射性示踪剂摄取量低的身体区域中，其中 标准的基于发射的数据驱动的运动估计方法很容易出错，这一点尤其重要。 在全身 PET 中，因为身体某个区域的运动可能会影响其他区域的 AC 和 SC。 贡献将提高新一代 PET 扫描仪的量化和诊断能力 将使超低剂量 PET 更广泛的临床和研究应用，特别是在敏感人群中 例如婴儿、儿童和青少年，从而更好地了解人类健康。