Abstract: A device is for repeated semi-invasive abrasion of lesions on the walls of hollow organs, in particular blood vessels or the gastrointestinal tract of a patient. The device includes an outer stent which, fixed in position at the site of the lesions, can be clamped against the wall of the hollow organ and has recesses through which the lesions can inwardly protrude. The device further includes a cutting body which is guided within the outer stent and only negligibly narrows the internal bore of the outer stent, which cutting body has cutting edges sliding on the inner side of the outer stent and is coupled magnetically to an external magnet system via which it can turn about the stent axis and/or can move longitudinally along the stent axis.

Abstract: A device is for introducing a stent into a hollow organ, in particular into the gastrointestinal tract of the body of a patient. The device includes a magnet system which covers the area of treatment of the patient and generates a 3D gradient field for remote-controlled movement and orientation of an endorobot. The endorobot is provided with a linear magnet and is freely movable in the hollow organ. Further, the stent, which can be uncoupled from the outside, is secured to the endorobot in a folded-down state so that it can be brought to the site of use and can there be opened out so as to bear firmly on the wall of the hollow organ.

Abstract: A linear drive device comprising at least one excitation winding for producing a variable magnetic field and is provided with an associated yoke body conducting a magnetic flux and an armature body which comprises a magnet carrier provided with at least two permanent magnet parts, preferably in the form of a plate, and to which an axial oscillation movement can be transferred by the magnetic field of the excitation winding. In order to avoid eddy currents in the magnet carrier, it is made of an electrically insulating material at least in the part thereof which penetrates into the magnetic field area defined by the pole surfaces of the yoke body and the excitation winding or which are arranged in said area. The magnet parts can be provided with ferromagnetic covers.

Abstract: For releasing a therapeutic agent, a release is disclosed. The release allows a release or expulsion of the therapeutic agent that is adapted appropriately for the therapy, and/or for the specific properties of the therapeutic agent.

Abstract: A device is for repeated semi-invasive abrasion of lesions on the walls of hollow organs, in particular blood vessels or the gastrointestinal tract of a patient. The device includes an outer stent which, fixed in position at the site of the lesions, can be clamped against the wall of the hollow organ and has recesses through which the lesions can inwardly protrude. The device further includes a cutting body which is guided within the outer stent and only negligibly narrows the internal bore of the outer stent, which cutting body has cutting edges sliding on the inner side of the outer stent and is coupled magnetically to an external magnet system via which it can turn about the stent axis and/or can move longitudinally along the stent axis.

Abstract: A device is for introducing a stent into a hollow organ, in particular into the gastrointestinal tract of the body of a patient. The device includes a magnet system which covers the area of treatment of the patient and generates a 3D gradient field for remote-controlled movement and orientation of an endorobot. The endorobot is provided with a linear magnet and is freely movable in the hollow organ. Further, the stent, which can be uncoupled from the outside, is secured to the endorobot in a folded-down state so that it can be brought to the site of use and can there be opened out so as to bear firmly on the wall of the hollow organ.

Abstract: In a method for the operation of a magnetic resonance apparatus having a gradient coil system as well as a shim system with a number of shim plates with respectively allocated heaters, at least one information signal indicating a change in shape and/or position of the gradient coil system is determined or employed, the regulation of the heaters, and thus the temperatures of the respective shim plates ensuing dependent thereon.

Abstract: A magnetic resonance apparatus has a basic field magnet with an inner unit, an outer unit and at least one middle unit that are essentially hollow-cylindrical and are electrically conductive and that are arranged inside one another such that the inner unit is enveloped by the middle unit and the middle unit is enveloped by the outer unit, and a gradient coil system which induces eddy currents at least in regions of the outer unit. At least the inner cylindrical jackets of the units are matched to one another in term of mechanical properties according so that the middle unit effectively damps oscillatory transmission from the outer unit to the inner unit that would otherwise occur due to magnetic coupling.

Abstract: In a method for the operation of a magnetic resonance apparatus having a gradient coil system as well as a shim system with a number of shim plates with respectively allocated heaters, at least one information signal indicating a change in shape and/or position of the gradient coil system is determined or employed, the regulation of the heaters, and thus the temperatures of the respective shim plates ensuing dependent thereon.

Abstract: A magnetic resonance apparatus has a basic field magnet with an inner unit, an outer unit and at least one middle unit that are essentially hollow-cylindrical and are electrically conductive and that are arranged inside one another such that the inner unit is enveloped by the middle unit and the middle unit is enveloped by the outer unit, and a gradient coil system which induces eddy currents at least in regions of the outer unit. At least the inner cylindrical jackets of the units are matched to one another in term of mechanical properties according so that the middle unit effectively damps oscillatory transmission from the outer unit to the inner unit that would otherwise occur due to magnetic coupling.

Abstract: An X-ray tube has a cathode and an anode arranged in a vacuum housing, the electron beam emanating from the cathode proceeding through a hollow cylindrical housing part of the vacuum housing to the anode. An electromagnet is provided for the deflection of the electron beam. The electromagnet has a U-shaped yoke with two legs having first ends connected to one another by a base section and having a winding surrounding the base section. The legs straddle the housing part and the electromagnet is disposed so that the electron beam is spaced a distance from the second ends of the legs so that from the second ends of the legs so that the electron beam is situated only in the stray field of the electromagnet, rather than in the region of maximum field strength.

Abstract: A magnetic bearing element contains a first bearing part attached to a shaft and a second, fixed-position, bearing part surrounding the first bearing part. One of the bearing parts contains an arrangement of a plurality of alternately polarized permanent magnetic elements between which there are ferromagnetic elements and the other bearing part contains a superconducting structure. This superconducting structure should have grains made of high-T.sub.c superconducting material, whose respective grain size is larger than the thickness of each of the permanent magnetic elements. In addition, the rotor shaft should be made of a non-magnetic material. The rotor shaft may contain the bearing part with permanent magnetic elements or the structure with the high-T.sub.c superconducting material.

Abstract: A magnetic resonance imaging apparatus for producing tomograms has a C-magnet with substantially planar pole faces for generating a magnetic field in the direction of the z-axis of a Cartesian coordinate system, for examining a human body having a body axis extending in the direction x-axis, the region to be examined being disposed between the pole pieces, gradient coils substantially parallel to the pole pieces, and a regulator for controlling the gradient currents of the gradient coils using the magnetic flux associated with each gradient coil as the measure value effecting such control. The gradient currents are adjusted dependent on disturbances in the magnetic flux which are caused by eddy currents and saturation effects in the ferromagnetic material in the proximity of the pole faces. Such a regulator can also be used in combination with gradient coils for generating a gradient in the z-direction for compensating for transient inhomogeneities in the main magnetic field.

Abstract: A gradient coil assembly for a magnetic resonance imaging apparatus includes respective gradient coils for the x-gradient and y-gradient which are flat coils provided at the respective planar pole surfaces of the fundamental field magnet. The gradient coils each consist of a number of turns, each turn including a straight conductor element and a return element which proceeds as azimuthally relative to the edge of the coil. The assembly also includes correction coils formed by two identical conductor segments, each segment contain arcuate conductor groups which are provided for correcting the linearity of the gradients in the edge regions of the gradient coils.

Abstract: A magnet system for a nuclear spin tomography installation contains annular superconducting coils for generating a magnetic background field and nonsuperconducting gradient coils. A hollow cylindrical thermal shield fits between the gradient coils and the superconducting coils. According to the invention, the thermal shield at the front faces is formed from tubular end pieces. The front faces have a greater specific electrical resistance than a tubular intermediate piece of the thermal shield that extends between the end pieces and cover at least the area of the gradient coils.

Abstract: A quench propagation device for a superconducting magnet having at least one pair of superconducting coils operates so that in the event of a transition to normal-conductance (quench) of a first coil of the coil pair, which up to that point was superconducting, the second coil of this pair is also converted from the superconducting operating state to the normal-conducting state using heating arrangements thermally connected to the coils. This device is constructed so that in the event of a quench rapid magnet de-excitation and uniform current distribution and, consequently force relationships, are achieved. The heating arrangements include two auxiliary windings magnetically closely coupled with their particular assigned coils of the coil pair. The auxiliary winding material is a discrete normal-conducting conductor having a predetermined specific electrical resistance.

Abstract: An arcuate shaped magnetic system is housed in a fixed cryostat within a rotating drum. A slurry containing magnetizable particles is charged into an operating area defined by the magnetic system at the lower part of the drum and magnetic particles adhering to the drum are removed as the drum rotates the same to a discharge location. The cryostat has an outer wall which conforms to the shape of the drum and houses a sector-shaped refrigeration tank. The refrigeration tank has an arcuate wall section conforming to the shapes of the cryostat wall and the drum and is positioned in close proximity to the outer cryostat wall only in the operating area in order to minimize inward heat transfer.

Abstract: A magnetic separator, in particular a drum separator, includes a magnetic system having a plurality of magnets. Each of the magnets produces an open field directed toward a separation zone which, in a drum separator, extends axially of the drum outside of the surface of the drum. The magnets may include conductive coils, preferably superconducting coils, which are traversed in the same direction by current and which include an iron-free core. The average center-to-center spacing of the coils is a maximum of 25 times the spacing between the coils and the separating zone and is preferably in the range of 15:1 to 10:1. The coils are elliptical and have major and minor axes which decrease from the outermost coil winding to the innermost coil winding, with the distances between the windings being greater along the major axes than along the minor axes.This is a continuation of application Ser. No. 843,737, filed Oct. 19, 1977, now abandoned.