Abstract: In a method and device for compensating the insufficient homogeneity of a magnetic field in a magnetic resonance system, the spatial position and size of a basic magnetic field region and at least one additional magnetic field region in a field to be homogenized and determined. An optimization calculation is implemented on the basic magnetic field region and the at least one additional magnetic field region. A homogenized magnetic field at the main magnetic field region and the at least one additional magnetic field region is output according to the result of the optimization calculation.

Abstract: In a method and apparatus for correcting the uniformity of a magnetic field, an active shim shell is placed in the magnetic field, a magnetic resonance image of the active shim shell obtained, and the placement position of the active shim shell is determined by analyzing the magnetic resonance image. The value of a shim current in the active shim shell is determined so as to meet the uniformity requirements of the magnetic field according to the placement position. The value of the shim current in said active shim shell is set to the determined value of the shim current.

Abstract: A magnetic field adjusting device includes a pair of opposing pole plates mounted on respective magnetic field generating sources, forming a magnetic field space; a plurality of shimming plugs movably mounted at the periphery of the pole plates, with each shimming plug being mounted in a radially oriented retaining groove, so as to be moveable in the direction of the retaining groove. Additionally, or alternatively, the circumferences of the magnetic field generating sources are arranged with adjusting bars which can move perpendicular to the pole plates.

Abstract: In a method and apparatus for correcting the uniformity of a magnetic field, an active shim shell is placed in the magnetic field, a magnetic resonance image of the active shim shell obtained, and the placement position of the active shim shell is determined by analyzing the magnetic resonance image. The value of a shim current in the active shim shell is determined so as to meet the uniformity requirements of the magnetic field according to the placement position. The value of the shim current in said active shim shell is set to the determined value of the shim current.

Abstract: In a method and device for compensating the insufficient homogeneity of a magnetic field in a magnetic resonance system, the spatial position and size of a basic magnetic field region and at least one additional magnetic field region in a field to be homogenized and determined. An optimization calculation is implemented on the basic magnetic field region and the at least one additional magnetic field region. A homogenized magnetic field at the main magnetic field region and the at least one additional magnetic field region is output according to the result of the optimization calculation.

Abstract: The present invention relates to a magnetic field adjusting device; such as may be used in MRI apparatus. The device can overcome the magnetic force to enable shimming plugs to move in a controlled continuous manner, thereby achieving continuous adjusting and accurate positioning. The magnetic field adjusting device comprises; a pair of opposing pole plates (3, 31), respectively mounted on magnetic field generating sources, forming a magnetic field space; a plurality of shimming plugs (42) movably mounted at the periphery of said pole plates (3, 31), each shimming plug (42) mounted in a radially oriented retaining groove (45), so as to be moveable in the direction of the retaining groove. Additionally, or alternatively, the circumferences of the magnetic field generating sources (5, 51) are arranged with adjusting bars (71, 81) which can move perpendicular to the pole plates.

Abstract: The present invention relates to a magnetic field adjusting device; such as may be used in MRI apparatus. The device can overcome the magnetic force to enable shimming plugs to move in a controlled continuous manner, thereby achieving continuous adjusting and accurate positioning. The magnetic field adjusting device comprises; a pair of opposing pole plates (3, 31), respectively mounted on magnetic field generating sources, forming a magnetic field space; a plurality of shimming plugs (42) movably mounted at the periphery of said pole plates (3, 31), each shimming plug (42) mounted in a radially oriented retaining groove (45), so as to be movable in the direction of the retaining groove. Additionally, or alternatively, the circumferences of the magnetic field generating sources (5, 51) are arranged with adjusting bars (71, 81) which can move perpendicular to the pole plates.

Abstract: In a shimming method for an irregular object to be examined by magnetic resonant equipment magnetic field parameters are measured at measurement points located on the surface of an irregular object to be examined. Based on the measured magnetic field parameters, the positions and number of shims for adjusting magnetic field homogeneity are calculated when a passive shimming is to be performed, or the current value in a shimming coil are calculated when an active shimming is to be performed, or at the same time both the positions and number of shims and current value in the shimming coil are calculated when active shimming and passive shimming are to be performed at the same time. Shimming is then performed according to the calculated results. These above steps are repeated until achieving required magnetic field homogeneity.