Low-field permanent magnet-based MRI systems are finding increasing use in portable, sustainable and point-of-care applications. In order to maximize performance while minimizing cost many components of such a system should ideally be designed specifically for low frequency operation. In this paper we describe recent developments in constructing and characterising a low-field portable MRI system for in vivo imaging at 50 mT. These developments include the design of (i) high-linearity gradient coils using a modified volume-based target field approach, (ii) phased-array receive coils, and (iii) a battery-operated three-axis gradient amplifier for improved portability and sustainability. In addition, we report performance characterisation of the RF amplifier, the gradient amplifier, eddy currents from the gradient coils, and describe a quality control protocol for the overall system.

中文翻译：

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改进的便携式和可持续低场 MRI 系统的设计、表征和性能

基于低场永磁体的 MRI 系统在便携式、可持续和即时护理应用中的使用越来越多。为了在最大限度地降低成本的同时最大限度地提高性能，理想情况下，此类系统的许多组件应该专门为低频操作而设计。在本文中，我们描述了构建和表征用于 50 mT 体内成像的低场便携式 MRI 系统的最新进展。这些开发包括 (i) 使用改进的基于体积的目标场方法的高线性梯度线圈的设计，(ii) 相控阵接收线圈，以及 (iii) 电池供电的三轴梯度放大器，以提高便携性和可持续性。此外，我们还报告了 RF 放大器、梯度放大器、来自梯度线圈的涡流、