内部扫描射频功率放大器漂移校正
Ali Aghaeifar1, Dario Bosch1,2, Rahel Heule1,2,3
1High-Field Magnetic Resonance Center, Max Planck Institute for Biological Cybernetics, Tuebingen, Germany.
Magnetic resonance in medicine
|March 12, 2024
概括
受工作周期影响的射频功率放大器 (RFPA) 漂移可以使用预测或运行时间方法进行纠正. 这些技术通过将平均漂移降低到1%以下,显著提高了MR信号稳定性.
科学领域:
- 磁共振成像 (MRI) 硬件开发 硬件开发
- 无线电频率 (RF) 工程
- 医学成像中的信号处理.
背景情况:
- 射频功率放大器 (RFPA) 是MRI系统中的关键组件,负责产生射频脉冲.
- 由于各种因素,RFPA性能随着时间的推移而降低,导致信号不稳定性和图像工件.
- 了解和减轻RFPA漂移对于保持高质量的MRI检查至关重要.
研究的目的:
- 评估RFPA的漂移特征,并确定关键的促成因素.
- 建议和评估两种新的方法,以对RFPA漂移进行前性纠正.
- 为了提高MRI中RF传输的稳定性和可靠性.
主要方法:
- 在不同扫描参数 (翻转角度,射频长度,TR) 下,使用脉冲内和脉冲间技术分析RFPA漂移.
- 定向合器 (DICOs) 监控RFPA输出波形,以计算传输电压的校正因数.
- 实施了两种校正策略:一种需要校准扫描的预测方法,另一种在扫描期间运行的运行时间方法.
主要成果:
- RFPA漂移受到RF工作周期的显著影响,在某些修订中,潜在漂移率高达41%.
- 翻转角度 (FA) 在低传输电压场景中对RFPA漂移的影响最小.
- 预测和运行时间校正方法都成功地将平均RFPA偏移从10.0%降低到不到1%,改善了MR信号稳定性.
结论:
- 使用DICO记录和反机制,可以对RFPA漂移进行前性纠正.
- 预测校正通过校准扫描提供了更简单的方法,适合许多应用.
- 运行时间校正方法提供了增强的性能,并推用于需要最大MR信号稳定性的应用.
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