Lurie David J, Davies Gareth R, Foster Margaret A, Hutchison James M S
Department of Bio-Medical Physics and Bio-Engineering, University of Aberdeen, Foresterhill, Aberdeen AB25 2ZD, UK.
Magn Reson Imaging. 2005 Feb;23(2):175-81. doi: 10.1016/j.mri.2004.11.051.
This paper describes the design, construction and use of a field-cycled proton-electron double-resonance imaging (FC-PEDRI) system for the detection and imaging of free radicals. The unique feature of this imager is its use of a 450-mT detection magnetic field in order to achieve good image quality and sensitivity. The detection magnetic field is provided by a superconducting magnet, giving high stability and homogeneity. Field cycling is implemented by switching on and off the current in an internal, coaxial, resistive secondary magnet that partially cancels the superconducting magnet's field at the sample; the secondary magnet is actively shielded to avoid eddy currents. EPR irradiation takes place at approximately 5 mT, following which the field is switched to 450 mT in 40 ms for NMR signal detection. Full details of the imager's subsystems are given, and experiments to image the distribution of stable free radical contrast agents in phantoms and in anesthetized rats are described.
本文描述了一种用于自由基检测和成像的场循环质子 - 电子双共振成像（FC - PEDRI）系统的设计、构建和使用。该成像仪的独特之处在于其使用450 mT的检测磁场，以实现良好的图像质量和灵敏度。检测磁场由超导磁体提供，具有高稳定性和均匀性。场循环通过开启和关闭内部同轴电阻次级磁体中的电流来实现，该次级磁体部分抵消样品处超导磁体的磁场；次级磁体经过主动屏蔽以避免涡流。电子顺磁共振（EPR）辐照在约5 mT下进行，之后在40 ms内将磁场切换至450 mT以进行核磁共振（NMR）信号检测。文中给出了成像仪子系统的详细信息，并描述了在体模和麻醉大鼠中对稳定自由基造影剂分布进行成像的实验。
