A strategy for achieving a low-field MRI magnet system with lightweight design and good magnetic field temperature stability

Abstract We developed a low field MRI magnet system utilizing a hybrid magnetic circuit composed of sintered neodymium iron boron (Nd–Fe–B) magnet and sintered samarium cobalt (Sm–Co) magnet based on the theoretical simulations. The static magnetic field of the magnet system with a magnetic pole plate diameter of 58 cm and a distance of 32 cm between the upper and lower pole plates reaches 0.07 T and exhibits magnetic field inhomogeneity fluctuations of less than 850 ppm over a temperature variation of ±4 °C around the set point of 24 °C. While it merely weighs 384 kg. Our findings indicate that a hybrid magnetic circuit composed of these two types of magnets contributes to both the lightweight design and temperature stability of the MRI magnet system. Finally, we evaluated the imaging effects of this magnet system.