SQUID detected NMR in microtesla magnetic fields
SQUID detected NMR in microtesla magnetic fields
复制标题
DOI：
10.1016/j.jmr.2004.05.015
复制
发表时间：
2004-09-01
影响因子：
2.2
通讯作者：
Kraus, RH
中科院分区：
文献类型：
--
作者：
Matlachov, AN;Volegov, PL;Kraus, RH
我们已经建立了一个核磁共振系统，采用超导量子干涉仪（SQUID）检测器，并在2-25 μ T的测量领域。该系统使用由简单的室温绕线线圈产生的4至30 mT的预极化场，该线圈在测量过程中关闭。该仪器具有开放的几何形状，室温下样本位于低温恒温器外部。这消除了对样本大小的限制，使我们能够从活组织中获得信号。我们已经获得了1H NMR光谱从各种样品，包括水，矿物油，和活青蛙。我们还获得了梯度编码的自由感应衰减（FID）数据从水塑料幻影在μ T制度，从简单的投影图像重建。还获得了金属容器内样品的NMR信号。这是可能的，因为在该系统的低操作频率下穿透趋肤深度比常规系统大得多。超低场NMR测量的优点包括由高强度极化和测量场引起的较低的磁化率伪影，以及由于测量场不均匀性引起的可忽略的线宽展宽，从而减少了产生高度均匀场的负担。(C)2004年爱思唯尔公司All rights reserved.
We have built an NMR system that employs a superconducting quantum interference device (SQUID) detector and operates in measurement fields of 2-25 muT. The system uses a pre-polarizing field from 4 to 30 mT generated by simple room-temperature wire-wound coils that are turned off during measurements. The instrument has an open geometry with samples located outside the cryostat at room-temperature. This removes constraints on sample size and allows us to obtain signals from living tissue. We have obtained I H NMR spectra from a variety of samples including water, mineral oil, and a live frog. We also acquired gradient encoded free induction decay (FID) data from a water-plastic phantom in the muT regime, from which simple projection images were reconstructed. NMR signals from samples inside metallic containers have also been acquired. This is possible because the penetration skin depth is much greater at the low operating frequencies of this system than for conventional systems. Advantages to ultra-low field NMR measurements include lower susceptibility artifacts caused by high strength polarizing and measurement fields, and negligible line width broadening due to measurement field inhomogeneity, reducing the burden of producing highly homogeneous fields. (C) 2004 Elsevier Inc. All rights reserved.