Passive decoupling due to low Q-factors of four-channel coils in 300-MHz pulsed EPR imaging
Passive decoupling due to low Q-factors of four-channel coils in 300-MHz pulsed EPR imaging
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300 MHz 脉冲 EPR 成像中四通道线圈的低 Q 因数导致的无源去耦
DOI：
10.1007/s00723-015-0671-6
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发表时间：
2015
影响因子：
1
通讯作者：
and N. Devasahayam
中科院分区：
文献类型：
--
作者：
A. Enomoto;K. Saito;S. Subramanian;M. C. Krishna;H. Hirata;and N. Devasahayam
本文介绍了一种用于体内时域电子顺磁共振（EPR）成像应用的四通道线圈阵列。通过射频脉冲EPR中所需的低品质因数实现了单个元件线圈的去耦，以适应成像带宽。在线圈阵列中没有使用有源解耦方法。用来自个人计算机的电压信号对连接到四通道线圈阵列的同轴开关进行远程控制。为了验证这个四通道线圈阵列的操作，充满顺磁性三芳基甲基自由基（OX063）的溶液的体模管进行可视化的脉冲EPR成像的基础上的单点方法，涉及纯相位编码。在体内实验中，通过脉冲EPR成像使荷瘤小鼠右后腿中的OX063可视化。即使没有有源去耦电路，由于品质因子低以及与邻近线圈的耦合系数低，当将各个线圈调谐到相同频率时，各个线圈的谐振也不会发生变化。线圈组件使我们能够研究比单个线圈元件更大的对象，从而能够以降低的总体比吸收率对更大的对象进行成像。这样的策略应该是有用的研究更大的物体的EPR成像。
This article describes a four-channel coil array for in vivo time-domain electron paramagnetic resonance (EPR) imaging applications. Decoupling of the individual element coils was achieved with the low-quality factors required in pulsed EPR at radiofrequency to accommodate the imaging bandwidth. No active decoupling method was used in the coil array. Remote control of a coaxial switch connected to the four-channel coil array was performed with voltage signals from a personal computer. To verify the operation of this four-channel coil array, a phantom tube filled with a solution of paramagnetic triarylmethyl radicals (OX063) was visualized by pulsed EPR imaging based on the single-point method involving pure phase encoding. In an in vivo experiment, OX063 in a mouse tumor-bearing right hind leg was visualized by pulsed EPR imaging. Even without active decoupling circuits, there was no shift in resonances for individual coils when those were tuned to the same frequency due to low quality factors and low coupling coefficients with neighboring coils. The coil assembly allowed us to study an object that was larger than an individual coil element, enabling the imaging of larger subjects with reduced overall specific absorption rate. Such strategies should be useful for studying larger objects by EPR imaging.