Development of a Combined MRI-PET System for Contemporaneous Functional Imaging

开发用于同步功能成像的 MRI-PET 组合系统

• 批准号: 8096561
• 负责人: RAYMOND ROBERT RAYLMAN
• 金额: $ 39.27万
• 依托单位: WEST VIRGINIA UNIVERSITY
• 依托单位国家: 美国
• 财政年份: 2009
• 资助国家: 美国
• 起止时间: 2009-09-01 至 2013-06-30
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/8096561
• 关键词: Affect; Algorithms; Animal Experimentation; Animal Model; Animals; Area; Attention; Beds; Biology; Biomedical Research; Bromides; Caliber; Clinical; Coupled; Custom; Data; Detection; Development; Devices; Diagnosis; Disease; Disease model; Elements; Fiber Optics; Functional Imaging; Functional Magnetic Resonance Imaging; Future; Generations; Goals; Health; Image; Imaging Techniques; Investigation; Lanthanum; Least-Squares Analysis; Light; Magnetic Resonance Imaging; Magnetic Resonance Spectroscopy; Measurement; Measures; Mechanics; Methods; Metric; Modality; Morphologic artifacts; Mus; Neurosciences; Oryctolagus cuniculus; Output; Performance; Pharmaceutical Preparations; Photons; Physiologic pulse; Positioning Attribute; Positron-Emission Tomography; Procedures; Process; RF coil; Radiation; Radiopharmaceuticals; Rattus; Research; Research Personnel; Resolution; Sampling; Scanning; Shapes; Signal Transduction; Small Animal Imaging Systems; Source; System; Target Populations; Techniques; Technology; Testing; Tissues; Tube; Weight; Work; attenuation; clinical application; design; detector; expectation; image reconstruction; image registration; imaging modality; improved; in vivo; innovation; interest; magnetic field; mouse model; multimodality; novel; oncology; photomultiplier; pre-clinical; programs; radiotracer; reconstruction; transmission process; uptake

DESCRIPTION (provided by applicant): Small animal imaging systems are rapidly becoming integral elements of many biomedical research programs, allowing the detailed study of animal models of a number of diseases. Recently, the multimodality imaging techniques originally developed for clinical use have been applied to pre-clinical applications. In this project we propose to create a combined MRI-PET imaging insert designed for quantitative contemporaneous imaging of small animals using a 3T clinical MRI. Thus, MRI-PET imaging can be made available to researchers who do not have access to the current generation of MRI-PET inserts designed for specialized high field, small animal MRI systems optimized for the imaging of mice. The MR-compatible PET component of the system will utilize continuous blocks of scintillator, coupled to microchannel plate, position-sensitive photomultiplier tubes (MCP- PSPMTs) located outside the bore of the MRI system via short fiber optic light guides. The use of light guides allows us to use high gain, large area photomultiplier tubes, which will maximize the field-of-view (FOV) of the PET to facilitate rapid imaging of animal species larger than mice (rats to rabbits). This capability is likely to be very important in the near future since a number of important disease models in these species have been developed and may be preferable to some mouse models. In addition, since there are no sensitive electrical components in the imaging area of the MRI scanner, no electrical shielding is required. Thus, there will be no conductive material in the MRI FOV that may produce eddy currents, which have been shown to affect MRI SNR. Degradation in some PET imaging performance metrics caused by attenuation of signal in the light guides will be offset by the use continuous blocks of a very high light output scintillator (LaBr3). Application of continuous block scintillator permits us to measure depth of photon interaction by using the shape of the light pulses. Furthermore, our system will include a rotating photon source in its design that will facilitate correction of photon attenuation effects. This capability is critical if the PET images are to be used for quantification of radiotracer concentration. In parallel, two custom transmit/receive MRI coil sets will be developed and tested. One coil set is designed for optimal MR imaging of rats, while the other is intended for animals up to the size of rabbits. MRI methods for acquiring anatomical, functional and spectroscopic MR data will be adapted for use with our new system. In addition, techniques will be implemented for segmenting the MRI images and co- registering the MRI, fMRI, and PET images. Finally, in addition to initial phantom testing, a small number of rats and rabbits will be imaged to demonstrate the imaging capabilities of the new system. The novel aspects of this device include the use continuous blocks of LaBr3, application of MCP-PSPMTs to create a large FOV MRI-PET system, acquisition of transmission scans for attenuation correction, implementation of PET image reconstruction methods that utilize structural information from MRI images and the development of interchangeable MRI-RF coils to fit the size of the animal species under investigation. At the completion of this project we will have built and initially tested a large FOV MRI-PET insert for use in clinical MRI 3T scanners, making this state-of-the-art technology available to an expanded number of researchers utilizing pre-clinical imaging techniques. PUBLIC HEALTH RELEVANCE: This application proposes the development of a large field-of-view combined MRI-PET animal imaging system. This device could be instrumental in the discovery of new drugs and methods to aid in the diagnosis and treatment of a large number of diseases.

描述（由申请人提供）：小动物成像系统正在迅速成为许多生物医学研究计划的组成部分，允许对许多疾病的动物模型进行详细研究。最近，最初为临床使用开发的多模态成像技术已被应用于临床前应用。在本项目中，我们建议创建一种组合式MRI-PET成像插件，旨在使用3 T临床MRI对小动物进行定量同期成像。因此，MRI-PET成像可以提供给研究人员，他们无法获得为专门的高场小动物MRI系统设计的最佳小鼠成像的当前一代MRI-PET插入物。系统的MR兼容PET组件将利用连续闪烁体块，通过短光纤光导耦合到位于MRI系统孔外的微通道板位置敏感光电倍增管（MCP-PSPMT）。光导的使用允许我们使用高增益、大面积光电倍增管，这将最大化PET的视场（FOV），以促进比小鼠大的动物物种（大鼠到兔子）的快速成像。这种能力在不久的将来可能非常重要，因为已经开发了这些物种的一些重要疾病模型，并且可能优于某些小鼠模型。此外，由于在MRI扫描仪的成像区域中没有敏感的电气部件，因此不需要电屏蔽。因此，MRI FOV中不会有可能产生涡流的导电材料，涡流已被证明会影响MRI SNR。光导中信号衰减导致的某些PET成像性能指标的退化将通过使用连续的高光输出闪烁体（LaBr 3）块来抵消。连续块闪烁体的应用允许我们通过使用光脉冲的形状来测量光子相互作用的深度。此外，我们的系统将在其设计中包括旋转光子源，这将有助于光子衰减效应的校正。如果PET图像要用于放射性示踪剂浓度的量化，则该能力是关键的。同时，将开发和测试两个定制发射/接收MRI线圈组。一个线圈组设计用于大鼠的最佳MR成像，而另一个线圈组则用于兔子大小的动物。用于获取解剖、功能和光谱MR数据的MRI方法将适用于我们的新系统。此外，将实施用于分割MRI图像和共配准MRI、fMRI和PET图像的技术。最后，除了初始体模测试外，还将对少量大鼠和家兔进行成像，以证明新系统的成像能力。该装置的新颖方面包括使用连续的LaBr 3块，应用MCP-PSPMT创建大FOV MRI-PET系统，采集用于衰减校正的透射扫描，实施PET图像重建方法，该方法利用来自MRI图像的结构信息，以及开发可互换的MRI-RF线圈以适应研究中动物物种的大小。在该项目完成时，我们将构建并初步测试用于临床MRI 3 T扫描仪的大FOV MRI-PET插入物，使这种最先进的技术可用于更多使用临床前成像技术的研究人员。公共卫生相关性：本申请提出开发一种大视场组合MRI-PET动物成像系统。该设备可能有助于发现新的药物和方法，以帮助诊断和治疗大量疾病。