Imaging the Brain in Motion: The Ambulatory Micro-Dose, Wearable PET Brain Imager

 描述（由申请人提供）：我们的愿景是设计第一个真正的移动的分子脑成像仪，可用于健康受试者，以研究人类大脑在运动过程中的功能。最终目标是能够在众所周知的“公园散步”和其他自然活动期间对主体进行成像。我们选择PET技术作为未来十年最有可能成功的技术，以提供这种大脑成像仪所需的功能。虽然MRI是一种非常强大和通用的成像方式，甚至有直立的MRI用于结构性脑扫描，但对于功能性MRI扫描，受试者必须在强场MRI磁体的狭窄孔内保持静止和水平位置。 我们的建议极具挑战性，如果不仔细规划其要求和实现预期性能的方法，就无法实现。在这种脑成像仪的移动使用变得可行之前，有几个主要的障碍需要克服。 第一个挑战是PET是一种核医学模式，需要处理对非卧床健康受试者和工作人员的辐射剂量和安全性问题。因此，我们必须（1）制定一项战略，大幅降低辐射剂量。我们假设，当使用全身PET/CT扫描仪进行成像时，低至标准注射剂量的1-10%的剂量将成为可能，而不会对成像程序的特定任务准确性产生不利影响。第二个挑战是（2）适当的放射性标记的PET成像剂的可用性和递送，随着设备的灵敏度的显著增加，将能够标记太低而不能用当前PET技术检测的神经靶点。第三个关键挑战是（3）机械/机器人的设计，允许舒适和安全的运动自由。显然，最关键的是降低辐射剂量，这取决于许多因素，首先是任务特定性能要求的定义，以及通过优化重建算法的模拟和开发进行的优化，通过选择优化的探测器设计和放射性标记的类型（C-11，O-15 vs F18等）。这种多参数分析只能通过仔细的分析和模拟来实现，伴随着探测器组件原型设计，并考虑到后续的赠款申请，以建议开发完整的原型。 我们的规划补助金的第一个也是至关重要的目标将是清楚地阐明对这种流动的、高灵敏度的PET成像仪的需求，并准备其应用和伴随的特定任务性能的列表。我们准备了一个初步的清单，证明流动PET概念的有效性，但我们需要深化它，并将操作要求与特定的成像任务相关联。我们预计，从我们的规划讨论，我们可能会设想一个以上的成像系统的设计，因为一个通用的系统可能是不够的。

 DESCRIPTION (provided by applicant): Our vision is to design the first truly mobile molecular brain imager that can be used on healthy subjects to study the functioning of the human brain during motion. The ultimate goal is to be able to image subjects during a proverbial "walk in the park" and other natural activities. We selected PET technology as the most likely to succeed in the next decade to provide the desired functionality of such a brain imager. While MRI is an exceptionally powerful and versatile imaging modality, and there are even upright MRIs for structural brain scans, for functional fMRI scans the subjects must stay still and in horizontal position inside a narrow bore of a strong-field MRI magnet. What we propose is extremely challenging and cannot be realized without careful planning for its requirements and the approaches to achieve the desired performance. There are several major obstacles to overcome before an ambulatory use of such a brain imager can become feasible. The first challenge is that PET is a nuclear medicine modality and one needs to deal with the issue of radiation dose and safety to the ambulatory healthy subjects and to the personnel. Therefore, we have to (1) develop a strategy to substantially lower the radiation doses. We hypothesize that doses as low as 1-10% of the standard injection dose when imaging with the whole body PET/CT scanners will become possible, without adversely impacting the task-specific accuracy of imaging procedures. The second challenge is (2) availability and delivery of the appropriate radiolabeled PET imaging agents that, with the substantially increased sensitivity of the device, will be able to tag neural targets that were too low to detect with current PET technology. The third key challenge is (3) the design of the mechanics/robotics allowing comfortable and safe freedom of movement. Clearly the most critical, lowering of the radiation dose, depends on many factors, starting with the definition of the task-specific performance requirements, and optimizations through simulation and development of optimized reconstruction algorithms, through selection of the optimized detector design, and of the type of the radioactive label (C-11, O-15 vs F18, etc.). This multi-parametrical analysis can be only achieved through careful analysis and simulation, accompanied by detector component prototyping, having in mind the follow-up grant application(s) to propose development of the full prototype. The first and critically important aim of our planning grant will be to articulate clearly the need for such an ambulatory, highly sensitive PET imager and prepare a list of its applications and accompanying task- specific performances. We prepared a preliminary list justifying the validity of the ambulatory PET concept, but we need to deepen it and associate operational requirements with particular imaging tasks. We anticipate that from our planning discussions we may envision more than one design of the imaging system, as one universal system may not suffice.