Cryo-coil HR-MAS Probe for SNR in NMR of Tissues

描述（由申请人提供）：最近，魔角纺纱（MAS） 结合高场高分辨率核磁共振技术 （HR-NMR）将该技术扩展到非均质系统，例如人类和 动物组织恶性乳腺癌组织的~ 1H HR-MAS谱显示 与非恶性乳腺癌相比， 组织，并且似乎可以识别其他明确的标记物 对于许多其他病理，如果HR-MAS的信噪比（SNR） 探头可以充分增加。用于液体的HR NMR探头具有非常 最近可用于低温冷却的样品线圈， 革命性的核磁共振领域，由于他们的四个因素的改善， 叶老在HR-MAS中，SNR的类似改进是可能的。工程 开发低温线圈HR-MAS探头的挑战似乎很大，但 这些问题将在拟议的 research.初级电路、计算流体动力学（CFD）和热 分析表明，（1）一种新的方法，四共振MAS的组合 （1 H-I 3C-2 H-I 5 N），所有关键电路元件保持在-35 K，（2）将陶瓷杜瓦瓶集成到新型样品旋转器设计中，以及（3） 低温激光器提供了SNR增加三倍的潜力， 在高达800 MHz的磁场下使用低温线圈HR-MAS探头。在我们小组的工作， 冷冻样品CP-MAS探针已经建立了建议的可行性， approach.该一期项目将证明脱水MAS的可行性 采用高效四共振低温回路的旋转器设计。NMR 实验将在7 T磁体中进行，样品在室温下 温度和电路在-90 K，以验证的基本特征， 低温系统设计第二阶段将完成必要的发展， 四共振低温线圈HR-MAS，脉冲场梯度高达 18.8 T（800 MHz）。预计将在外部机构进行初步现场测试 到第二阶段结束。

DESCRIPTION (provided by applicant): Recently, Magic Angle Spinning (MAS) has been combined with high-field high-resolution Nuclear Magnetic Resonance (HR-NMR) to extend the technique to inhomogeneous systems, such as human and animal tissues. The 1 H HR-MAS spectrum of malignant breast cancer tissue shows dramatically increased levels of phosphocholine compared to nonmalignant breast tissue, and it appears likely that other unambiguous markers can be identified for many other pathologies if the signal to noise ratio (SNR) of the HR-MAS probe can be increased sufficiently. HR NMR probes for liquids have very recently become available with cryogenically cooled sample coils that promise to revolutionize the field of NMR owing to their factor-of-four improvement in SNR. Similar improvements in SNR may be possible in HR-MAS. The engineering challenges of developing a cryo-coil HR-MAS probe appear substantial but not insurmountable, and they will be systematically addressed in the proposed research. Preliminary circuit, computational fluid dynamics (CFD), and thermal analyses show that a combination of (1) a novel approach to quad-resonance MAS (1 H-I 3C-2H-I 5N) with all of the critical circuit elements maintained at -35 K, (2) integrating a ceramic dewar into a novel sample spinner design, and (3) cryogenic preamps offers the potential for a factor-of-three increase in SNR in a cryo-coil HR-MAS probe at fields up to 800 MHz. Prior work in our group with cryo-sample CP-MAS probes has established the viability of the proposed approach. This Phase I project will demonstrate feasibility of a dewared MAS spinner design with a high-efficiency quad-resonance cryogenic circuit. NMR experiments will be performed in a 7 T magnet with the sample at room temperature and the circuit at -90 K to validate essential features of the cryogenic system design. Phase II will complete the developments necessary for quad-resonance cryo-coil HR-MAS with pulsed field gradients at fields up to 18.8 T (800 MHz). Initial field testing at an outside institution is expected by the end of Phase II.