Magnetic resonance apparatus with a gradient coil system structured for reduced noise emission

#1. Field of the Invention

#The invention concerns a magnetic resonance device of the type having a cavity and with a gradient coil system arranged in the cavity.

#2. Description of the Prior Art

#FIG. 1 is a longitudinal section through a magnetic resonance device with a gradient coil system that is supported in a middle region against the basic field magnet and is adhered in edge regions with the basic field magnet, in accordance with the invention.

#FIG. 2 is a longitudinal section through a magnetic resonance device with a gradient coil system that is supported in a middle region against the basic field magnet and is wedged in edge regions with the basic field magnet in accordance with the invention.

#FIG. 1 shows as an exemplary embodiment of the invention a longitudinal section through a magnetic resonance device. To generate a static basic magnetic field, the magnetic resonance device thereby has a superconducting basic field magnet 10 with a cavity 12 that is distended like a barrel in a middle region 14 and is cylindrically fashioned in edge regions 16 and 18 that connect to both sides of the middle region 14. The basic field magnet 10 is, for example, designed corresponding to the above-cited German OS 101 56 770.

#To generate gradient fields, a gradient coil system 20 is mounted in the cavity 12 of the basic field magnet 10. The gradient coil system 20 is formed by two structurally independent units 22 and 24 shaped as hollow cylinders, each of the units 22 and 24 respectively including also the coils of gradient coils of the gradient coil system 20. Each of the units 22 and 24 thus has saddle-shaped partial coils of a first transversal gradient coil two further saddle-shaped partial coils of a second transversal gradient coil, and a solenoid-like partial coil of a longitudinal gradient coil. The units 22 and 24 thereby correspond, for example, to those described in the above-cited German OS 197 22 211, produced with a typical vacuum flow method.

#Furthermore, the gradient coil system 20 has a carrier 26 produced from a glass and/or carbon fiber-reinforced synthetic, in the edge regions of which both units 22 and 24 are attached, separated from one another. The carrier 26 has a passive shim system, for which purpose the carrier 26 is fashioned with corresponding acceptance openings for the insertion of shim carriers filled with ferromagnetic shim elements. The plate-like shim elements are screwed down or adhered to the shim carrier. In another embodiment, the shim elements can be contained in shim boxes.