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High resolution NMR imaging using a high field yokeless permanent magnet.
Katsumi Kose1, Tomoyuki Haishi
1Institute of Applied Physics, University of Tsukuba, Ibaraki, Japan. kose@bk.tsukuba.ac.jp
Summary
This study shows a high-field, yokeless permanent magnet is effective for high-resolution nuclear magnetic resonance (NMR) imaging. Its stable magnetic field enables detailed imaging of biological samples.
Area of Science:
- Physics
- Biophysics
- Magnetic Resonance Imaging
Background:
- High-resolution imaging requires stable and homogeneous magnetic fields.
- Yokeless permanent magnets offer potential advantages in size and field strength for specialized applications.
Purpose of the Study:
- To evaluate the magnetic field homogeneity and stability of a 1.04-tesla yokeless permanent magnet.
- To assess its suitability for high-resolution nuclear magnetic resonance (NMR) imaging.
Main Methods:
- Magnetic field homogeneity was assessed using 3D lattice phantom and spin-echo imaging.
- Field stability was monitored over 68 hours by measuring temperature and NMR frequency.
- A mathematical model was developed to describe the magnet's thermal properties.
Main Results:
- The magnet achieved a peak-to-peak inhomogeneity of ~60 ppm and RMS of 8 ppm within a 20-mm diameter central sphere.
- Thermal properties were modeled, and stability was confirmed over extended periods.
- High-resolution (down to 20 µm) imaging of biological samples was successfully performed.
Conclusions:
- The evaluated yokeless permanent magnet demonstrates excellent performance for high-resolution NMR imaging.
- Its stability and homogeneity make it a valuable tool for advanced biological sample analysis.
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