Magnetic Resonance Materials in Physics Biology and Medicine ( IF 2.0 ) Pub Date : 2023-01-30 , DOI: 10.1007/s10334-023-01063-5 Nicolas Boulant 1 , Lionel Quettier 2 ,
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Objectives
The Iseult MRI is an actively shielded whole-body magnet providing a homogeneous and stable magnetic field of 11.7 T. After nearly 20 years of research and development, the magnet successfully reached its target field strength for the first time in 2019. This article reviews its commissioning status, the gradient–magnet interaction test results and first imaging experience.
Materials and methods
Vibration, acoustics, power deposition in the He bath, and field monitoring measurements were carried out. Magnet safety system was tested against outer magnetic perturbations, and calibrated to define a safe operation of the gradient coil. First measurements using parallel transmission were also performed on an ex-vivo brain to mitigate the RF field inhomogeneity effect.
Results
Acoustics measurements show promising results with sound pressure levels slightly above the enforced limits only at certain frequency intervals. Vibrations of the gradient coil revealed a linear trend with the B0 field only in the worst case. Field monitoring revealed some resonances at some frequencies that are still under investigation.
Discussion
Gradient-magnet interaction tests at up to 11.7 T are concluded. The scanner is now kept permanently at field and the final calibrations are on-going to pave the road towards the first acquisitions on volunteers.
中文翻译：
Iseult CEA 11.7 T 全身 MRI 的调试：现状、梯度-磁相互作用测试和首次成像经验
目标
Iseult MRI 是一种主动屏蔽的全身磁体，可提供 11.7 T 的均匀稳定磁场。经过近 20 年的研发，该磁体在 2019 年首次成功达到其目标场强。本文回顾了其调试状态、梯度-磁体相互作用测试结果和首次成像体验。
材料和方法
进行了振动、声学、He 浴中的功率沉积和现场监测测量。磁体安全系统针对外部磁扰动进行了测试，并进行了校准以定义梯度线圈的安全操作。还对离体大脑进行了使用并行传输的首次测量，以减轻 RF 场不均匀性效应。
结果
声学测量显示出令人鼓舞的结果，声压级仅在特定频率间隔内略高于强制限制。梯度线圈的振动仅在最坏的情况下显示出与 B 0场的线性趋势。现场监测显示某些频率的共振仍在调查中。
讨论
结束了高达 11.7 T 的梯度磁体相互作用测试。扫描仪现在永久保存在现场，最终校准正在进行中，为首次对志愿者进行采集铺平道路。
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