SQUID-Controlled Noise Reduction Coils for Fetal MCG

描述(由申请人提供)： 该方案的目标是创建一种低成本、轻量化、有源降噪系统，以抑制磁心动图(MCG)，特别是胎儿心磁图(FMCG)的电磁噪声干扰。该设备将沿着一个测量轴运行，这可能足以满足FMCG的要求尽管MCG(和MEG)为临床医生提供了独特的、非侵入性的生物功能诊断方法，但该技术容易受到环境电磁噪声的影响，需要使用大量且昂贵的磁屏蔽室(MSR)，这在许多场所是不切实际的。我们建议用一个结合了两个商业开发组件的系统来取代快速消费品的MSR：主动抵消和参考Squds。我们的系统将只有数百磅重，大约是MSR的1110英镑。该系统将是一个亥姆霍兹线圈降噪装置，但它的新颖之处在于不是由室温(磁通门)磁力计驱动，而是由MCG测量仪器本身内置的一组SQUID参考通道驱动。初步结果表明，噪声消除将在100赫兹以下最有效，这将覆盖许多临床感兴趣的信号，在MSR性能最差的低频(0.01-1赫兹)尤其有效。 降噪系统将降低研究和临床MCG仪器的成本并提高其性能，并将有助于将非侵入性MCG纳入更多研究人员、临床研究人员和临床专家的预算范围。这一优势对于小规模、轻量级的MCG系统尤其明显，包括那些使用氮气温度鱿鱼运行的系统。与脑磁图和成人心磁图相比，选择快速心磁图应用意义重大，因为非侵入性胎儿EKG是不可能的；单一的心磁图数据通道是无价的(定位不是问题)；感兴趣的信号(1-10PT)相对于脑磁图诱发区域(50-100FT)很大。该计划将包括修改现有的放大器和线圈组，这些设备已经由ETS-Lindgren进行了商业开发。特里斯坦将基于其自己的商业系统，利用先前在生物老年学应用中测试的组件，制造一种基于鱿鱼的仪器。该系统将在真实的噪声环境中进行测试，并在不同距离使用已知噪声源。

DESCRIPTION (provided by applicant): The goal of this proposal is to create a low cost, lightweight, active noise reducing system to quiet electromagnetic noise interference for magnetocardiography (MCG), especially fetal magnetocardiography (fMCG). The device will operate along one measurement axis, which may suffice for fMCG Although MCG (and MEG) provides clinicians with unique, noninvasive diagnostic measures of biological function, the technology is vulnerable to environmental electromagnetic noise, necessitating the use of massive and expensive magnetically shielded rooms (MSRs), which are impractical for many sites. We propose to replace the MSR for fMCG with a system combining two commercially developed components: active cancellation and reference SQUiDs. Our system will weigh just hundreds of pounds and will be approximately 1110 the cost of an MSR. The system will be a Helmholtz-coil noise reduction device, but will be novel in not being driven by room-temperature (fluxgate) magnetometers, but instead by a set of SQUID reference channels built into the MCG measurement instrument itself. Preliminary results suggest that the noise cancellation will be most effective below 100 Hz, which will cover many signals of clinical interest, and will be especially effective at low frequencies (.01 - 1 Hz) where MSR performance is poorest. The noise reduction system will lower costs and improve performance for research- and clinical MCG instruments, and will help bring noninvasive MCG into the budgetary range of more researchers, clinical researchers, and clinical specialists. This advantage will be especially strong for small scale, lightweight MCG systems, including those that operate with nitrogen temperature SQUiDs. The choice of fMCG application, in comparison with MEG and adult MCG is significant, since noninvasive fetal EKG is impossible; a single MCG channel of data is invaluable (localization is not at issue); and the signal of interest is large (1-10 pT) in relation to MEG evoked fields (50-100 fT). The plan will involve modifying an existing amplifier and coil set, already developed commercially by ETS-Lindgren. Tristan will build a SQUID-based instrument, based on its own commercial systems, from components tested on prior biomagetism applications. The system will be tested in a realistic noise setting, and with known noise sources at varying distances.