波谱学杂志

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L波段三维ESR成像系统的研制(Ⅱ)——L波段三维ESR成像系统

郑莹光1, 许 静2,董凤霞1,沈尔中3,徐玉书2,吴可, 丛建波, 先宏, 王长振, 张清俊   

  1. 吉林大学 1.分析测试中心; 2.原子与分子物理研究所; 3.理论化学研究所,吉林长春 130023;军事医学科学院放射医学研究所,北京 100850
  • 收稿日期:2002-11-29 修回日期:2003-03-03 出版日期:2003-06-05 发布日期:2003-06-05
  • 作者简介:郑莹光(1945-),女,北京人,研究员, 从事ESR研究工作.
  • 基金资助:

    国家自然科学基金重点资助项目(29935080)

DEVELOPMENT OF L-BAND THREE DIMENSIONAL ESR IMAGING SYSTEM(Ⅱ)——L-Band Three Dimensional ESR Imaging System

ZHENG Ying-guang1,  XU JING2, DONG Feng-xia1,  SHEN Er-zhong3, XU Yu-shu2, WU  Ke,  CONG Jian-bo,  XIAN Hong, WANG Chang-zheng, ZHANG Qing-jun   

  1. 1.Analysis and Measurement Center Jilin University;  2.Institute of Atom and Molecule Physics,Jilin  University;  3.Institute of Theoretical Chemistry,  Jilin University,Changchun 130023, China; Institute of Radiation Medicine, Academy of Military Medical Science, Beijing 100850, China
  • Received:2002-11-29 Revised:2003-03-03 Online:2003-06-05 Published:2003-06-05
  • Supported by:

    国家自然科学基金重点资助项目(29935080)

摘要:

叙述了一个L波段(1.05 GHz)用于ESR和ESR成像的装置,用这套自制装置实现了3D ESR成像. 该装置由L波段ESR谱仪、三组梯度场线圈及控制单元和PC机数据采集系统组成. 样品腔是一个3-环2-缝再进入式谐振腔,可放入直径为20 mm、 长30 mm的H2O样品,空谐振腔的频率是1.05 GHz. 微波振荡频率用自动频率控制(AFC)的方法自动锁在有载腔的频率上. 梯度场线圈沿X-Y-Z-轴产生线性梯度场,在中心40 mm球形范围内梯度场强度为2 mT/cm. 依照Lauterbur's方法进行3D ESR 图像重建. 用该系统检测了样品中TEMPO氮氧自由基的3D空间分布. 得到了TEMPO的2D、3D ESR图像、用像素灰度表示的自旋密度分布图及3D ESR-CT图像.

关键词: ESR, 成像系统, L波段, 梯度场, 3D图像重建, ESR-CT

Abstract:

An apparatus for ESR and ESR imaging at L-band (1.05 GHz) was built in our laboratory, consisting of L-band ESR spectrometer, three sets of gradient coils and a personal computer-based data acquisition system. The sample cavity is a 3-loop 2-gap reentrant resonator, accepting samples with sizes up to 20 mm in diameter and 30 mm in length. The resonance frequency of unloaded resonator is 1.05 GHz. The microwave oscillator frequency is locked to the resonant frequency of loaded resonator by means of automatic frequency control (AFC). Linear magnetic field gradients (up to 2 mT/cm in amplitudes) in the X-, Y-, and Z-directions are produced by gradient coils, and have a linear range of 40 mm measuring from the center of the magnet. All projections in imaging were acquired as single scans with constant sweep time. To accurately compute the spatial distribution of the spins, the line shape function that causes line-broadening of the ESR signals needs to be removed from the observed projections. Three- dimensional ESR image is constructed based on the Lauterbur's method. Using this system, we studied the spatial distribution of TEMPO (2,2,6,6-tetramethylpiperidine-1-oxyl) nitroxide radicals in sample tube. Stack images of ESR-CT and 2D, 3D ESR images were obtained.

Key words: ESR, imaging system, L-band, field gradient, 3D image construction, ESR-CT

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