Advertisement

A Cryogen-Free 0.5 TESLA MRI Magnet for Head Imaging

  • J. M. van Oort
  • E. T. Laskaris
  • P. S. Thompson
  • B. Dorri
  • K. G. Herd
Part of the Advances in Cryogenic Engineering book series (ACRE, volume 43)

Abstract

A compact, cryogen-free 0.5 T superconducting Magnetic Resonance Imager (MRI) magnet for heads and limbs has been developed using conductively-cooled NbTi coils in conjunction with a 4.2 K Gifford-McMahon (GM) refrigerator. The bell-shaped magnet configuration fits over the shoulders of the patient and provides a 20 cm spherical volume to image the head. The magnet is also suitable to image human limbs.

The lightweight magnet cartridge is designed for rapid cool-down, quench recovery, and field ramping, as required for clinical applications in small offices, intensive care units, and mobile vans. The NbTi coils are wound on a copper coil form, surrounded by a single aluminum thermal shield and a stainless steel vacuum envelope. The GM cold-head stages are in direct contact with the coil form and thermal shield through flexible connections to provide maximum vibration isolation.

Descriptions of the design, fabrication, and test results of the magnet are presented.

Keywords

Gradient Coil Coil Temperature Copper Cylinder Thermal Shield Flexible Copper 
These keywords were added by machine and not by the authors. This process is experimental and the keywords may be updated as the learning algorithm improves.

Preview

Unable to display preview. Download preview PDF.

Unable to display preview. Download preview PDF.

References

  1. 1.
    Laskaris, E.T., Herd, K.G. and Dorri, B., “A compact 0.8 T superconducting MRI magnet”, Cryogenics, vol. 34, suppl. issue:65–8, 1994.Google Scholar
  2. 2.
    Laskaris, E.T., Dorri, B. and Herd, K.G., “Superconducting magnet for imaging human limbs”, U.S. Patent 5,304,934, April 1994.Google Scholar
  3. 3.
    Laskaris, E.T., Ackermann, R. Dorri, B., Gross, D., Herd, K. and Minas, C, “A cryogen-free open superconducting magnet for interventional MRI applications”, IEEE Transactions on Applied Superconductivity, vol. 5, no.2, pt.l: 163–8, June 1995.CrossRefGoogle Scholar
  4. 4.
    Dorri, B. and Vermilyea, M.E., “Method of optimizing passive shim placement in magnetic resonance magnets”, U.S. Patent 5,045,794, September 1991.Google Scholar
  5. 5.
    Dorri, B. Vermilyea, M.E. and Toffolo, W.E., “Passive shimming of MR magnets: algorithm, hardware and results”, IEEE Transactions on Applied Superconductivity, V3, Nl, March 1992.Google Scholar
  6. 6.
    Dorri et al., “Over-shoulder MRI magnet for human brain imaging”, U.S. Patent 5,416,415, May 1995.Google Scholar

Copyright information

© Springer Science+Business Media New York 1998

Authors and Affiliations

  • J. M. van Oort
    • 1
  • E. T. Laskaris
    • 1
  • P. S. Thompson
    • 1
  • B. Dorri
    • 1
  • K. G. Herd
    • 1
  1. 1.GE Corporate Research and Development CenterNiskayunaUSA

Personalised recommendations