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: 7915244
• 负责人: RAYMOND ROBERT RAYLMAN
• 金额: $ 52.25万
• 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/7915244
• 关键词: Affect; Algorithms; Animal Experimentation; Animal Model; Animals; Area; Arts; 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; Image; Imaging Techniques; Investigation; Lanthanum; Least-Squares Analysis; Light; Magnetic Resonance Imaging; 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; Spectrum Analysis; 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; public health relevance; 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(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，最初为临床使用而开发的多模式成像技术已被应用于临床前应用。在这个项目中，我们建议创建一种MRI-PET组合成像插入物，设计用于使用3T临床MRI对小动物进行定量同期成像。因此，MRI-PET成像可以提供给无法获得为专门的高场小动物MRI系统优化的小鼠成像而设计的当前一代MRI-PET插入物的研究人员。该系统的MR兼容PET组件将利用连续的闪烁体块，通过短光纤光导连接到微通道板、位于MRI系统孔外的位置敏感光电倍增管(MCP-PSPMT)。通过使用光导，我们可以使用高增益、大面积的光电倍增管，这将最大限度地扩大PET的视野(FOV)，便于快速成像比老鼠更大的动物物种(从大鼠到兔子)。这种能力在不久的将来可能非常重要，因为这些物种中的一些重要疾病模型已经开发出来，可能比一些小鼠模型更可取。此外，由于MRI扫描仪的成像区域中没有敏感的电子部件，因此不需要电气屏蔽。因此，MRI FOV中将不会有可能产生涡流的导电材料，而涡流已被证明会影响MRI SNR。由于光导中的信号衰减而导致的一些PET成像性能指标的降级将通过使用非常高的光输出闪烁体(LaBr3)的连续块来抵消。连续块闪烁体的应用使我们可以利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，这将有助于校正光子衰减效应。如果要将PET图像用于放射性示踪剂浓度的量化，这一能力是至关重要的。同时，将开发和测试两套定制的发射/接收核磁共振线圈组。其中一套线圈是为大鼠的最佳磁共振成像而设计的，而另一套线圈是为兔子大小的动物设计的。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，还将实施分割MRI图像和共同配准MRI、fMRI和PET图像的技术。最后，除了最初的模型测试外，还将对少量的老鼠和兔子进行成像，以展示新系统的成像能力。该设备的创新方面包括使用连续的LaBr3块，应用MCP-PSPMT创建大型FOV MRI-PET系统，获取用于衰减校正的透射式扫描，实施利用MRI图像的结构信息的PET图像重建方法，以及开发适合所研究动物物种大小的可互换MRI-RF线圈。在这个项目完成后，我们将建造并初步测试用于临床MRI 3T扫描仪的大型FOV MRI-PET插入物，使更多使用临床前成像技术的研究人员可以使用这项最先进的技术。公共卫生相关性：本申请建议开发一种大视野MRI-PET联合动物成像系统。这种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。