title: Development of High-Field Permanent Magnetic Circuits for NMRI/MRI and Imaging on Mice.
abstract: The high-field permanent magnetic circuits of 1.2 T and 1.5 T with novel magnetic focusing and curved-surface correction are developed. The permanent magnetic circuit comprises a magnetic yoke, main magnetic steel, nonspherical curved-surface magnetic poles, plugging magnetic steel, and side magnetic steel. In this work, a novel shimming method is proposed for the effective correction of base magnetic field (B 0) inhomogeneities, which is based on passive shimming on the telescope aspheric cutting, grinding, and fine processing technology of the nonspherical curved-surface magnetic poles and active shimming adding higher-order gradient coils. Meanwhile, the magnetic resonance imaging dedicated alloy with high-saturation magnetic field induction intensity and high electrical resistivity is developed, and nonspherical curved-surface magnetic poles which are made of the dedicated alloy have very good anti-eddy-current effect. In addition, the large temperature coefficient problem of permanent magnet can be effectively controlled by using a high quality temperature controller and deuterium external locking technique. Combining our patents such as gradient coil, RF coil, and integration computer software, two kinds of small animal Micro-MRI instruments are developed, by which the high quality MRI images of mice were obtained.
authors.affiliation: College of Science, North China University of Science and Technology, Tangshan 063000, China.
authors.forename: Guangxin
authors.initials: G
authors.lastname: Wang
authors.affiliation: Shanghai Shining Global Science and Education Equipment Corporation, Ltd., Shanghai 201806, China.
authors.forename: Huantong
authors.initials: H
authors.lastname: Xie
authors.affiliation: Fundamental Medical College, North China University of Science and Technology, Tangshan 063000, China.
authors.forename: Shulian
authors.initials: S
authors.lastname: Hou
authors.affiliation: College of Science, North China University of Science and Technology, Tangshan 063000, China.
authors.forename: Wei
authors.initials: W
authors.lastname: Chen
authors.affiliation: Fundamental Medical College, North China University of Science and Technology, Tangshan 063000, China.
authors.forename: Xiuhong
authors.initials: X
authors.lastname: Yang
mesh_terms: D000818:Animals; D003952:Diagnostic Imaging / Q000379:methods*; D004867:Equipment Design; D060526:Magnetic Fields; D008279:Magnetic Resonance Imaging / Q000379:methods*; D051379:Mice; D000078702:Radiofrequency Therapy; D059629:Signal-To-Noise Ratio; D012984:Software