Superconducting Magnets for MRI

@article{Williams1984SuperconductingMF,
  title={Superconducting Magnets for MRI},
  author={John E. C. Williams},
  journal={IEEE Transactions on Nuclear Science},
  year={1984},
  volume={31},
  pages={994-1005}
}
(iii) Because of the limitations imposed by permanent and resistive magnets, particularly on field strength, the superconducting magnet is now most widely used to provide background fields of up to 2 T for whole body MRI. It requires very low operating power and that only for refrigeration. Because of the constant low temperature, 4.2 K, at which its stressed structure operates, its field is stable.