Povolni Pavel, Bendfeld Robin, Maltsev Sergej, Samlow Judith, Glang Felix, Valsala Praveen Iyyappan, Goerner Dominique, Bosch Dario, Mueller Sebastian, Birk Florian, Buckenmaier Kai, Scheffler Klaus
High‑Field Magnetic Resonance Center, Max Planck Institute for Biological Cybernetics, 72076, Tübingen, Germany.
Institute for Nonlinear Mechanics, Department of Mechanical Engineering, University of Stuttgart, 70569, Stuttgart, Germany.
MAGMA. 2025 Apr 5. doi: 10.1007/s10334-025-01239-1.
Low-field magnetic resonance imaging is currently developing into a valuable diagnostic tool due to its simplicity of magnet array designs. Particularly, this allows the development of scanners as part of educational workshops, thus ensuring knowledge transfer and empowering local scientists to design tailored solutions for specific local problems. To obtain the maximum performance, the magnet needs to be shimmed requiring an automated system measuring the spatial magnetic field distribution.
A self-designed measuring probe based on commercial integrated Hall sensor chips is used and optimized by calibrating it in an easy-to-build calibration system. For positioning of the sensor, a low-cost five-degree-of-freedom robot arm is used and improved by camera-based motion tracking for precise localization of the sensor.
The system is able to map the field of a -Halbach desktop MR magnet, as well as a self-designed x-gradient (used inside the magnet) with an efficiency of . The built-up Hall sensor demonstrates a level of precision that is competitive with commercial sensors. The entire positioning system can be freely scaled to accommodate larger designs by adjusting the kinematics.
The presented system is demonstrated to be comparable to already established measurement systems, while the costs, setup times, and mapping duration are greatly reduced.
低场磁共振成像由于其磁体阵列设计简单，目前正发展成为一种有价值的诊断工具。特别是，这使得扫描仪能够作为教育工作坊的一部分进行开发，从而确保知识转移，并使当地科学家有能力为特定的当地问题设计量身定制的解决方案。为了获得最佳性能，磁体需要进行匀场，这需要一个测量空间磁场分布的自动化系统。
使用基于商用集成霍尔传感器芯片自行设计的测量探头，并通过在易于构建的校准系统中对其进行校准来进行优化。对于传感器的定位，使用了一个低成本的五自由度机器人手臂，并通过基于摄像头的运动跟踪进行改进，以实现传感器的精确定位。
该系统能够以 的效率绘制一个 - 哈尔巴赫桌面式磁共振磁体的磁场，以及一个自行设计的x梯度（用于磁体内部）。所构建的霍尔传感器显示出与商用传感器相当的精度水平。整个定位系统可以通过调整运动学结构自由缩放，以适应更大的设计。
所展示的系统被证明与已有的测量系统相当，同时成本、设置时间和测绘持续时间都大大降低。
