Development of ESR spectrometer using magnetic field gradient modulation for redox function measurement among small animals

作为分析生物氧化还原状态的一种新方法，将ESR时空成像技术应用于小动物体内，以硝基自由基为自旋探针。然而，当各种自由基共存或ESR线形状发生变化时，该方法无法获得准确的图像。为了实现小动物用环隙谐振器调制梯度法，研制了低涡流屏蔽壳和高速响应场梯度线圈。在0.12 mT/mm的场梯度下，空间分辨率约为6.8 mm。并对两类自由基的EPR谱进行了分离。

As a present method to analyze the redox state in a living thing, an ESR spatiotemporal imaging technique is applied to a small animal receiving a nitroxyl radical as a spin probe. In this method, however, the accurate images are not obtained when various radicals co-exist or the ESR line shape changes. In this paper, the development of the shield case with low eddy current and the field gradient coils with high speed response is reported in order to realize the modulated gradient method using the loop-gap resonator for a small animal. The spatial resolution was determined to be about 6.8 mm at the field gradient of 0.12 mT/mm. The separation of the EPR spectra of two types of radicals was also made.