Development of L-band Electron Spin Resonance Imaging System for Small Animals

我们研制了一种新型的L波段微波ESR成像系统。1. ESR成像系统的构建本课题研制的ESR成像系统由L波段ESR谱仪、场梯度线圈和数据处理器组成。谱仪采用环隙谐振器，环隙中有电屏蔽，工作频率为700- 800 NHz，工作电压约为100 V。30 mT.2.in体内ESR光谱法使用了几种氮氧自由基，并将每种氮氧自由基静脉注射到大鼠体内。将老鼠头插入谐振器中。成功地观察到头部的ESR，并获得了具有良好信噪比的光谱。ESR信号随时间衰减。结果表明，通过观察硝罗韦在大鼠体内的衰减速率，可以分析硝罗韦在大鼠体内的代谢和/或排泄情况。3. ESR成像（1）二维图像：在生理盐水溶液中，以氮氧自由基3-氨基甲酰基-2，2，5，5-四甲基吡咯烷-1-基氧基（CPROXYL）为显像剂。二维 ...更多信息 用XY、YZ和ZX平面投影法，分别拍摄小鼠腿和大鼠头的放射性分布的单像。图像与受试者体内氮氧自由基的位置和分布相对应。（2）ESR-CT图像：大鼠接受CPROXYL腹腔给药。在横截面（水平和横轴，厚度为1.5mm）上进行分布成像。这些图像配得上ESR-CT的名字。在大鼠头部的横截面图像中，氮氧化合物富集区域与氮氧化合物缺乏区域明显区分开。氮氧缺乏区与大鼠脑组织相对应。由于脑内有血脑屏障，所以CPROXYL可能会滞留在脑内，其在脑内的浓度很低，因此ESR信号很弱。其在血液中的浓度高，ESR信号很强。我们认为我们的系统已经发展成为一个很好的L波段ESR成像系统，可以用于研究含有外源性自由基的大鼠或小鼠。少

We developed a novel ESR imaging system for rats or mice using the L-band microwave.l.Construction of ESR imaging system The system developed in this project is composed of an L-band ESR spectrometer, a field gradient coil and a data processor. The spectrometer is equipped with a loop-gap resonator having an electric shield in the loop, and is operated at 700-800NHz under ca. 30 mT.2.in vivo ESR spectroscopy Several kinds of nitroxide radicals were used and each was intravenously injected into the rat. The rat head was inserted into the resonator. ESR was successfully observed for the head and obtained the spectra with a good S/N ratio. The ESR signal decayed with time. We showed that the metabolism and /or the excretion in the rat for the nitroixed can be analyzed by the observation of the decay rate.3.ESR imagings (1)Two dimensional images: A nitroxide radical, 3-carbamoyl-2,2,5,5,-tetramethylpyrrolidine- 1-yloxy (CPROXYL), was used as an imaging agent in saline solution. Two dimensi … More onal images of the distribution of the radical in the mouse legs or the rat head were made by the projection to the XY, YZ and ZX planes. The images corresponded well to the location and the distribution of the nitroxide radical in the subjects. (2)ESR-CT images: The rat received the intraperitoneal administration of CPROXYL. The imaging was made on the distribution in the cross sectional plane (horizontal and transaxial, 1.5mm in thickness). The images deserve the name of ESR-CT. In the cross-sectional image of the rat head the nitroxide rich region was clearly distinguished from the deficient region. The nitroxide deficient areas corresponded well to brain of the rat. Since the brain holds the blood brain barrier, CPROXYL may be retained here and its concentration in the brain is quite low, which gives weak ESR signals.Its high concentration in the blood gives strong ESR signals.We believe our system has been well developed as an L-band ESR imaging system and is available to studies on a rat or a mouse containing exsogenous radicals. Less