用于均匀激发和无伪影射频时域电子顺磁共振成像的定制 sinc 脉冲。

Tailored sinc pulses for uniform excitation and artifact-free radio frequency time-domain EPR imaging.

作者信息

Devasahayam N, Murugesan R, Matsumoto K, Mitchell J B, Cook J A, Subramanian S, Krishna M C

机构信息

Radiation Biology Branch, Center for Cancer Research, National Cancer Institute, National Institutes of Health, Bethesda, MD 20892, USA.

出版信息

J Magn Reson. 2004 May;168(1):110-7. doi: 10.1016/j.jmr.2004.01.016.

DOI:10.1016/j.jmr.2004.01.016

PMID:15082255

Abstract

A method to generate shaped radiofrequency pulses for uniform excitation of electron spins in time-domain radio frequency (RF) electron paramagnetic resonance (EPR) imaging is presented. A commercial waveform generator was integrated with the transmit arm of the existing time-domain RF-EPR spectrometer to generate tailored excitation pulses with sub-nano second resolution for excitation with a 90 degrees flip-angle. A truncated sinc [sin(x)/x] pulse, tailored to compensate for the Q-profile (RF frequency response) of the resonator, was shown to yield images from phantom objects as well as in vivo images, with minimal distortion. These studies point to the advantages in using shaped sinc pulses to achieve improved uniform excitation over a relatively wide bandwidth region in time-domain RF-EPR imaging (RF-FT-EPRI).

摘要

本文提出了一种在时域射频（RF）电子顺磁共振（EPR）成像中生成用于均匀激发电子自旋的成形射频脉冲的方法。将商用波形发生器与现有时域RF-EPR光谱仪的发射臂集成，以生成具有亚纳秒分辨率的定制激发脉冲，用于90度翻转角激发。一个经过调整以补偿谐振器Q轮廓（RF频率响应）的截断正弦[sin(x)/x]脉冲，被证明能够产生来自模型物体的图像以及体内图像，且失真最小。这些研究指出了在时域RF-EPR成像（RF-FT-EPRI）中使用成形正弦脉冲在相对较宽的带宽区域实现更好的均匀激发的优势。