Abstract: An MR tomograph, the magnet system (2) and gradient system of which permit access to the investigation volume along at least two essentially orthogonal axes, comprises a positioning system for the exact determination of the position of a manually guided manipulator (12) relative to the measuring object (6) which is investigated by means of imaging MR measurement and located in the investigation volume (3) of the MR tomograph (1); with a mounting frame (11) with which the manipulator (12) is connected via movable mechanics comprising a measuring means through which the respective spatial position of the manipulator (12) relative to the mounting frame (11) can be determined, wherein the measuring means of the movable mechanics does not utilize any MR signals and wherein the measured position of the manipulator (12) is displayed on the MR image. In this way, minimum-invasive operations, e.g.

Abstract: An RF coil system (1) for an MR tomograph comprising a magnet coil system and a gradient coil system is characterized in that the RF coil system is constructed of two partial systems (2, 2') which are arranged essentially laterally reversed with respect to a plane z=0 containing the centre of the measuring volume and have a distance g/2 from the plane z=0, and that each partial system (2, 2') comprises at its axial end facing the plane z=0, a compensation section (3, 3') for homogenizing the RF field drop in the measuring volume caused by the axial gap between the partial systems (2, 2') as compared with an axially continuous and undivided RF coil system (1). The RF coil system (1) in accordance with the invention allows lateral access to the investigation volume in the radial direction and/or offers the possibility to integrate in the RF coil system an adjustment, fixing or support ring surrounding the investigation volume.

Abstract: Magnet arrangement for a one-sided NMR tomography system having a permanent magnetic ring (4) of an outer radius R.sub.a and an inner radius R.sub.i and being magnetized axially in the direction of the z-axis and extending in the axial direction up to a plane E (z=z.sub.E) for generating a homogeneous magnetic field B in a measuring volume (2) is characterized in that, in a radial region R<R.sub.i, at least one further permanent magnetic field-generating element, which is rotationally symmetric, is arranged with respect to the plane E on the same side as the permanent magnetic ring (4) at an axial distance from plane E, whereby a depression V is formed on the surface of the magnet arrangement (1) facing plane E and that the permanent magnetic field-generating elements generate at least 90%, preferably 99% of the homogeneous magnetic field B in the measuring volume (2).

Abstract: An NMR tomography magnet system (1) comprises a cryostat having a horizontal room temperature bore (2) with a diameter d between 20 cm and 40 cm having a vessel (3) filled with liquid helium. In intimate thermal contact with the liquid helium is a superconducting solenoid coil (4) with a horizontal axis (100; z=0) for the production of a static homogeneous magnetic field B in a homogeneity volume (5) within the room temperature bore (2). The center of the homogeneity volume is located at a separation l.sub.m from an axial end (z=0) of the room temperature bore (2) and the outer skin (6) of the cryostat exhibits, at the depth l.sub.m from an axial end of the room temperature bore (2) and at least in an angular region about the horizontal cryostat axis (100), minimum separations h.sub.e, h from the inside of the room temperature bore (2) whereby l.sub.m, h.sub.e <35 cm, preferentially<30 cm, and h<50 cm.

Abstract: A magnet system for nuclear spin resonance spectroscopy, in particular for in-vivo spectroscopy and tomography on a limb or a shoulder of a human body (partial-body tomography) comprising a superconductive magnet coil arrangement having coil sets (2a, 3a; 2b, 3b) arranged at an axial spacing one from the other, for generating a static homogeneous magnetic field in an examination volume, and further a coil frame (6) carrying the coil sets and a cryostat intended for cooling the windings, is characterized by the fact that the windings are rigidly interconnected by the coil frame at low temperature and that there is provided a transverse room-temperature access (50) to the examination volume which extends over approximately 180.degree. in circumferential direction, related to the axis (4) of the magnet coil arrangement. This enables examinations to be carried out at ease.

Abstract: In an NMR apparatus with a system of gradient coils for the production of a magnetic field gradient within a measurement volume (1) within a field coil, the transverse gradient coils are constructed unsymmetrically with respect to the z=0 plane dividing the measurement volume (1), however largely mirror symmetric to a x=0 or y=0 plane containing the z axis, and possess only two partial coils (20', 20''; 40', 40'') whose windings each exhibit the same winding direction. The axial gradient coils are cylindrically symmetric with respect to the z axis and totally unsymmetric with respect to the z=0 plane, and consist of at least two partial coils which are arranged on differing sides of z=0 plane, whereby the partial coils on one side largely exhibit the opposite winding direction than the coils on the other side, and whereby the number of coils with a particular winding direction is not equal to the number of coils with the opposite winding direction.

Abstract: A nuclear magnetic resonance spectrometer, in particular a nuclear spin tomograph serving to investigate biological samples, comprising a magnetic coil for generating a substantially homogeneous magnetic field in a volume under examination, and a set of shim coils for eliminating any remaining inhomogeneities of the magnetic field is characterized in that at least one additional electric conductor, preferably an additional shim coil, is provided which may be arranged in the volume under examination, in the direct vicinity of the sample, that the additional conductor is designed in such a way that it will generate an inhomogeneous magnetic field when loaded with current, and that it can be loaded with currents of a type generating inhomogeneous magnetic fields which will eliminate, at least partially, and in a selected area in the sample, local field inhomogeneities resulting from susceptibility variations within the sample, for example. This enables the accuracy of the spectroscopy results to be improved.

Abstract: A nuclear spin tomograph comprises a magnet system with a, preferably, elongated holder (19,20) for a test object arranged in its one axis to slide in the longitudinal direction. The test object is further surrounded by coil systems for generating gradient fields and for irradiating a radio-frequency field. The magnet system is provided with a yoke iron body (10) enclosing a longitudinal opening (11) for receiving the test object, with outer marginal areas of the longitudinal opening (11) accommodating coil sections (12, 12'; 13, 13') which extend in the direction of the longitudinal opening (11), which are bent over at the ends thereof and which close above the opening (11) (FIG. 1).

Abstract: For recording the nuclear magnetic resonance in selected areas of a body for the purpose of representing body cross-sections in the form of images (NMR tomography), wherein the nuclear spins of a selected type present in the area of one plane of the body are subjected to a superimposed gradient field varying in the selected cross-sectional plane, and selectively excited, the excitation of the nuclear spins is effected by application of a pulse sequence which induces the nuclear spins to supply at one stage a number of chronologically successive induction signals. The induction signals corresponding to each other in chronolical sequence are then processed to obtain separate sets of image signals so that by one single measurement a sequence of cross-sectional images is obtained which differ from each other by the intensity of the excited nuclear spins which varies according to the relaxation times T.sub.1 or T.sub.2.

Abstract: An apparatus produces complete stereoscopic images of a three-dimensional object. It comprises an image transmitter (13) on which are shown one after the other in time two-dimensional images (14) corresponding to sections lying one behind the other in space. In addition, the element (18) is provided which is disposed between the image transmitter (13) and an observer (36), said element being synchronously controlled by the image transmitter (13) and changing the spatial positioning of the image (14) between image transmitter (13) and observer (36). Optical means (31, 32) serve to reduce an image (14) shown on the image transmitter (13) in the plane of the element (18) and to re-enlarge it for analysis. The apparatus is particularly suitable for showing tomographic pictures, i.e. for imaging the inside of a living body.

Abstract: An electromagnet for generating the constant magnetic field required in NMR tomography includes a superconductive coil system consisting of at least one circular cylindrical field coil (1) and at least one correction coil (2, 3) concentric with the field coil. The coil system is enclosed in a ferromagnetic cylindrical shell (13) whose influence on the homogeneity of the magnetic field is compensated by the particular dimensioning of the field and correction coils. The magnetic field is produced by the coil system (1, 2, 3) in the interior space defined by it, which space is accessible and suitable to receive the body presented for examination. The cylindrical shell (13) may be closed at its ends by ring-shaped ferromagnetic plates (14). The cylindrical shell (13), complete with plates (14), may directly form the exterior wall of the Dewar.

Abstract: An electromagnet for producing the constant magnetic field required in NMR tomography comprises a coil system (1, 2, 3, 4) of the Helmholtz double coil type. The coil system is enclosed in, and supported by, a stable cylindrical shell (5). The influence exerted by the cylindrical shell (5) on the homogeneity of the magnetic field, which is generated by the coil system in an accessible interior space defined by it and suitable to receive the body to be examined, is compensated by the particular dimensioning of the field and error coils (1, 2, 3, 4). The cylindrical shell (5) is best made of a ferromagnetic material having low electric conductivity and is constructed of a plurality of axially serially disposed annular discs (6) which are preferably divided into sectors.