Skip to main content
SpringerLink
Log in

An Optimized 2 MHz Unilateral Magnet with a Large Homogeneous Sensitive Spot

  • Original Paper
  • Published:
Applied Magnetic Resonance Aims and scope Submit manuscript

Abstract

We introduce an optimized design for a three-magnet array unilateral magnetic resonance (MR) device. The sensitive spot is 0.5 cm3, and begins roughly 0.5 cm from the magnet surface with a field variation of less than 1.5% of the B0 resonant frequency. 3D simulation was used in conjunction with a trust-region optimization method to determine the optimal magnet geometry to achieve a large sensitive spot. A standard surface coil was used to excite and detect the MR signal from the sensitive spot. The array has dimensions of 8.4 × 7.4 × 4.1 cm and a mass of 0.74 kg. The surface of the magnets are shielded with a thin layer of copper tape to avoid acoustic ringing. Attenuation of the B1-field due to eddy currents in the copper sheet was reduced by displacing the coil from the surface, at the cost of working distance. The quality factor and B1-field attenuation due to eddy currents are explored experimentally by incrementally displacing the coil from the magnet surface. A minor reduction in working distance increases the sensitivity of the measurement. To assess device performance, T1, T2, T1–T2, and diffusion measurements were undertaken with a cod liver oil phantom.

This is a preview of subscription content, log in via an institution to check access.

Access this article

Log in via an institution

Price excludes VAT (USA)
Tax calculation will be finalised during checkout.

Instant access to the full article PDF.

Institutional subscriptions

Fig. 1
Fig. 2
Fig. 3
Fig. 4
Fig. 5
Fig. 6
Fig. 7
Fig. 8
Fig. 9
Fig. 10
Fig. 11
Fig. 12

Similar content being viewed by others

References

  1. S. Utsuzawa, E. Fukushima, J. Magn. Reson. (2017). https://doi.org/10.1016/j.jmr.2017.07.006

    Article  Google Scholar 

  2. G. Eidmann, R. Savelsberg, P. Blümler, B. Blümich, J. Magn. Reson. (1996). https://doi.org/10.1006/jmra.1996.0185

    Article  Google Scholar 

  3. A.E. Marble, I.V. Mastikhin, B.G. Colpitts, B.J. Balcom, J. Magn. Reson. (2007). https://doi.org/10.1016/j.jmr.2007.01.020

    Article  Google Scholar 

  4. F. Casanova, J. Perlo, B. Blümich, Single-Sided NMR (Springer, Germany, 2011)

    Book  Google Scholar 

  5. B. Blümich, S. Haber-Pohlmeier, W. Zia, Compact NMR (De Gruyter, Berlin, 2014)

    Book  Google Scholar 

  6. J. Blümich, F. Perlo, Casanova. Prog. Nucl. Magn. Reson. (2008). https://doi.org/10.1016/j.pnmrs.2007.10.002

    Article  Google Scholar 

  7. W.L. Rollwitz, Agric. Eng. 66, 12–14 (1985)

    Google Scholar 

  8. B.J. Hogan, Des. News 44, 108–109 (1986)

    Google Scholar 

  9. B. Blümich, Adv. Mater. (1991). https://doi.org/10.1002/adma.19910030504

    Article  Google Scholar 

  10. G.A. Matzkanin, H.T., Yolken, Am Soc Mech Eng 429, 1–6 (2000)

  11. B. Manz, A. Coy, R. Dykstra, C.D. Eccles, M.W. Hunter, B.J. Parkinson, P.T. Callaghan, J. Magn. Reson. (2006). https://doi.org/10.1016/j.jmr.2006.07.017

    Article  Google Scholar 

  12. P. Guo, W. He, J.C. Garcia-Naranjo, Sensors (2014). https://doi.org/10.3390/s140406797

    Article  Google Scholar 

  13. A.E. Marble, G. LaPlante, I.V. Mastikhin, B.G. Colpitts, B.J. Balcom, Can. Conf. Electr. Comput. Eng. (2006). https://doi.org/10.1109/CCECE.2006.277535

    Article  Google Scholar 

  14. M.N. Martin, B.J. Balcom, M.J. McCarthy, M.P. Augustine, J. Food Sci. (2019). https://doi.org/10.1111/1750-3841.14778

    Article  Google Scholar 

  15. A.E. Marble, I.V. Mastikhin, B.G. Colpitts, B.J. Balcom, J. Magn. Reson (2005). https://doi.org/10.1016/j.jmr.2005.01.009

    Article  Google Scholar 

  16. J.C. García-Naranjo, I.V. Mastikhin, B.G. Colpitts, B.J. Balcom, J. Magn. Reson. (2010). https://doi.org/10.1016/j.jmr.2010.09.018

    Article  Google Scholar 

  17. H. Caytak, MSc. Thesis, Signal Optimization for Unilateral NMR Magnet Design. Carleton Institute for Biomedical Engineering, 2011

  18. D. M. Gruber, S. N. Fricke, V. Lee, B. J. Balcom, M. P. Augustine, Coils for Large Standoff Relaxometry with Unilateral Magnets (2021, submitted)

  19. W. Sun, Y.X. Yuan, Optimization Theory and Method: Nonlinear Programming (Springer, Dordrecht, 2006), pp. 303–323

    Google Scholar 

  20. J. Mispelter, M. Lupu, A. Briguet, NMR Probeheads for Biophysical and Biomedical Experiments: Theoretical Principles and Practical Guidelines (Imperial College Press, London, 2006), pp. 507–509

    Book  Google Scholar 

  21. S. Anferova, V. Anferov, M. Adams, P. Blümler, N. Routley, K. Hailu, K. Kupferschläger, M.J.D. Mallett, G. Schroeder, S. Sharma, B. Blümich, Conc. Magn. Reson. (2002). https://doi.org/10.1002/cmr.10013

    Article  Google Scholar 

  22. E. Fukushima, S.B.W. Roeder, J. Magn. Reson. (1979). https://doi.org/10.1016/0022-2364(79)90203-8

    Article  Google Scholar 

  23. I.P. Gerothanassis, Prog. NMR. Spectrosc. (1987). https://doi.org/10.1016/0079-6565(87)80005-5

    Article  Google Scholar 

  24. F. David Doty, in Encyclopedia of Magnetic Resonance (2007). https://doi.org/10.1002/9780470034590.emrstm0414.pub2

  25. J.R. Moser, IEEE (1967). https://doi.org/10.1109/TEMC.1967.4307447

    Article  Google Scholar 

  26. D.I. Hoult, R.E. Richards, J. Magn. Reson. (1976). https://doi.org/10.1016/0022-2364(76)90233-X

    Article  Google Scholar 

  27. S.L. Duce, T.A. Carpenter, L.D. Hall, J. Food Eng. (1992). https://doi.org/10.1016/0260-8774(92)90032-2

    Article  Google Scholar 

  28. H.Y. Carr, E.M. Purcell, Am. Phys. Soc. (1954). https://doi.org/10.1103/PhysRev.94.630

    Article  Google Scholar 

  29. M. Fleury, M. Romero-Sarmiento, J. Magn. Reson. (2016). https://doi.org/10.1016/j.petrol.2015.11.006

    Article  Google Scholar 

  30. A.J. Easteal, W.E. Price, L.A. Woolf, J. Chem. Soc. (1989). https://doi.org/10.1039/F19898501091

    Article  Google Scholar 

  31. B. Hills, A. Costa, N. Marigheto, K. Wright, Appl. Magn. Reson. (2005). https://doi.org/10.1007/BF03166990

    Article  Google Scholar 

Download references

Acknowledgements

We acknowledge financial support from the Natural Sciences and Engineering Research Council (NSERC) for a Discovery grant [2015-6122]. B.J.B thanks the Canada Research Chairs Program for a Research Chair in Materials Science Magnetic Resonance Imaging. We thank Andrés Ramirez-Aguilera for technical assistance during simulation and fabrication of the magnet-array.

Author information

Authors and Affiliations

  1. Department of Physics, UNB MRI Centre, University of New Brunswick, Fredericton, E3B 5A3, Canada

    Devin M. Morin, Peiyuan Yan & Bruce J. Balcom

  2. Department of Chemistry, University of California, One Shields Avenue, Davis, CA, 95616, USA

    Matthew P. Augustine

Authors
  1. Devin M. Morin
    View author publications

    You can also search for this author in PubMed Google Scholar

  2. Peiyuan Yan
    View author publications

    You can also search for this author in PubMed Google Scholar

  3. Matthew P. Augustine
    View author publications

    You can also search for this author in PubMed Google Scholar

  4. Bruce J. Balcom
    View author publications

    You can also search for this author in PubMed Google Scholar

Corresponding author

Correspondence to Bruce J. Balcom.

Additional information

Publisher's Note

Springer Nature remains neutral with regard to jurisdictional claims in published maps and institutional affiliations.

Rights and permissions

Reprints and permissions

About this article

Check for updates. Verify currency and authenticity via CrossMark

Cite this article

Morin, D.M., Yan, P., Augustine, M.P. et al. An Optimized 2 MHz Unilateral Magnet with a Large Homogeneous Sensitive Spot. Appl Magn Reson 53, 401–415 (2022). https://doi.org/10.1007/s00723-021-01455-7

Download citation

  • Received:

  • Revised:

  • Accepted:

  • Published:

  • Issue Date:

  • DOI: https://doi.org/10.1007/s00723-021-01455-7

Search

Navigation