A Cryogen-Free, Low-Cost Atomic Magnetometer Array for Magnetoencephalography

用于脑磁图的无制冷剂、低成本原子磁力计阵列

• 批准号: 8296381
• 负责人: Peter D. D. Schwindt
• 金额: $ 80.87万
• 依托单位: SANDIA CORP-SANDIA NATIONAL LABORATORIES
• 依托单位国家: 美国
• 财政年份: 2012
• 资助国家: 美国
• 起止时间: 2012-06-01 至 2016-05-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/8296381
• 关键词: Accounting; Acoustic Nerve; Algorithms; Area; Auditory; Brain; Cells; Child; Clinical; Collaborations; Comparative Study; Computer software; Cost Savings; Coupled; Dementia; Devices; Electroencephalography; Elements; Epilepsy; Evaluation; Finland; Freedom; Frequencies; Functional Magnetic Resonance Imaging; Glass; Goals; Head; Helium; Helmet; Human; Image; Individual; Lasers; Lead; Left; Liquid substance; Location; Magnetism; Magnetoencephalography; Measurement; Measures; Mental Depression; Mental disorders; Metals; Mind-Body Method; Modeling; Modification; Neurons; Noise; Performance; Persons; Positioning Attribute; Radial; Research; Research Infrastructure; Resolution; Schizophrenia; Signal Transduction; Site; Source; Subject Headings; Surface; System; Techniques; Temperature; Validation; Work; auditory stimulus; base; cost; cryogenics; design; human subject; improved; instrument; magnetic field; median nerve; meter; millisecond; nervous system disorder; neural circuit; neuroimaging; optical fiber; programs; prototype; quantum; relating to nervous system; response; sensor; simulation; somatosensory; success; superconducting quantum interference device; tool

DESCRIPTION (provided by applicant): Functional neuroimaging has led to important advances in understanding neural circuits and has emerged as an important technique in the study of psychiatric and neurological disorders such as schizophrenia, dementia, depression, and epilepsy, where anatomical imaging is negative or shows only nonspecific findings. Magnetoencephalography (MEG) is the only noninvasive functional neuroimaging technique able to directly measure neural activity with sub-centimeter spatial and millisecond temporal resolution, but its potential as a research and clinical tool has yet to be realized on a large scae due to its high acquisition and operating costs. A large portion of the cost results from the use o superconducting quantum interference device (SQUID) magnetic sensors that must be cooled with liquid helium. The cryogenic infrastructure results in a bulky MEG system that requires installation of a large magnetically shielded room to achieve acceptably low background levels and that has a fixed sensor array geometry that cannot be adjusted for head size. The goal of the proposed work is to develop a small, low-cost MEG system using an array of atomic magnetometers (AMs) as replacements for SQUIDs. AMs can achieve sensitivities comparable to SQUIDs but do not require cryogenic cooling. AMs detect magnetic fields by measuring, via laser interrogation, the interaction between a magnetic field and atoms contained within a glass cell. Recently, we developed a compact optical fiber-coupled AM and used it to detect MEG signals from human subjects. Based on these preliminary studies, we propose to develop a 36-channel array of AMs with partial-head coverage (roughly 12 cm X 12 cm) that is able detect and localize neuronal activity. In Specific Aim #1, we will design critical components of the proposed AM MEG system, including the individual AMs that serve as array elements and a person-sized magnetic shield to contain the AM-array and the human subject. Commercially available magnetic source localization software will be adapted to our array geometry. One AM will be constructed and its performance will be verified at go/no-go specifications of >100 Hz bandwidth and 20 fT/Hz1/2sensitivity. In Specific Aim #2, the AM MEG system will be constructed and its source localization accuracy will be determined by detecting an MEG phantom with the AM array geometry reconfigured to mimic a variety of head sizes. Human studies will commence only after demonstrating sub-centimeter spatial resolution. In Specific Aim #3, the AM system will be compared to a commercial SQUID MEG system by measuring the evoked response in human subjects from median nerve and auditory stimuli with both systems. A successful comparison will identify a neural source in terms of strength and location to within one standard deviation error between the two systems. The results of the proposed work are expected to clear the path for developing a full-head- coverage low-cost AM MEG system that can be adapted to accommodate a wide variety of head sizes. PUBLIC HEALTH RELEVANCE: Magnetoencephalography (MEG) is a valuable tool for functional neuroimaging because it can directly measure neural activity with sub-centimeter spatial resolution (better than EEG) and millisecond temporal resolution (better than functional MRI), but its potential has yet to be realized on a large scale due to its high acquisition costs ( $2.5 million) and annual operating costs (> $200,000). This goal of this project is to develop an MEG system that replaces the current bulky liquid helium cooled sensors with an array of atomic magnetometers that do not require liquid helium cooling and the large magnetically shielded room currently required with a person-sized magnetic shield. An atomic magnetometer-based MEG system would provide substantial cost savings increasing the availability of MEG, a reduction size of the device for potential portable applications, and the ability adjust the size o the MEG helmet increasing the utility of the device particularly with children.

描述（由申请人提供）：功能性神经成像在理解神经回路方面取得了重要进展，并已成为精神和神经系统疾病（如精神分裂症、痴呆、抑郁症和癫痫）研究中的重要技术，其中解剖成像为阴性或仅显示非特异性结果。脑磁图（Magnetoencephalography，MEG）是唯一一种能够直接测量神经活动的无创性功能性神经成像技术，其空间分辨率和时间分辨率分别为亚厘米级和毫秒级，但由于其高昂的获取和操作成本，其作为研究和临床工具的潜力尚未在大规模上实现。成本的很大一部分是由于使用超导量子干涉器件（SQUID）磁传感器，这些传感器必须用液氦冷却。低温基础设施导致庞大的MEG系统，其需要安装大的磁屏蔽室以实现可接受的低背景水平，并且具有不能针对头部尺寸进行调整的固定传感器阵列几何形状。拟议工作的目标是开发一个小型，低成本的MEG系统，使用原子磁力计（AM）阵列作为SQUID的替代品。AM可以实现与SQUID相当的灵敏度，但不需要低温冷却。AM通过激光询问测量磁场与玻璃单元内原子之间的相互作用来检测磁场。最近，我们开发了一种紧凑的光纤耦合AM，并使用它来检测从人体受试者的脑磁信号。基于这些初步研究，我们建议开发一个36通道阵列的AM部分头部覆盖（约12厘米× 12厘米），能够检测和定位神经元活动。在具体目标#1中，我们将设计拟议AM MEG系统的关键组件，包括用作阵列元件的单个AM和用于容纳AM阵列和人体受试者的人体大小的磁屏蔽。商用磁源定位软件将适用于我们的阵列几何形状。将建造一个AM，并将在>100 Hz带宽和20 fT/Hz 1/2灵敏度的通断规格下验证其性能。在特定目标#2中，将构建AM MEG系统，并通过检测MEG体模来确定其源定位精度，其中AM阵列几何结构重新配置为模拟各种头部尺寸。只有在展示了亚厘米空间分辨率之后，才能开始人体研究。在具体目标#3中，将通过测量人类受试者对两种系统的正中神经和听觉刺激的诱发反应，将AM系统与商业SQUID MEG系统进行比较。成功的比较将在两个系统之间的一个标准差误差内识别强度和位置方面的神经源。所提出的工作的结果，预计开发一个全头部覆盖的低成本AM MEG系统，可以适应各种头部尺寸的道路。 公共卫生关系：脑磁图（Magnetoencephalography，MEG）是一种有价值的功能性神经成像工具，因为它可以直接测量神经活动，具有亚厘米级的空间分辨率（优于EEG）和毫秒级的时间分辨率（优于功能性MRI），但由于其高昂的采购成本（250万美元）和年运营成本（> 20万美元），其潜力尚未大规模实现。该项目的目标是开发一种MEG系统，该系统用不需要液氦冷却的原子磁力计阵列取代当前笨重的液氦冷却传感器，并且目前需要一个人大小的磁屏蔽的大型磁屏蔽室。基于原子磁力计的MEG系统将提供显著的成本节约，增加MEG的可用性，减小用于潜在便携式应用的装置的尺寸，以及调节MEG头盔的尺寸的能力，增加装置的实用性，特别是对于儿童。