Abstract: A mechanical stabilizer-tuned damper is attachable to the first upper magnet assembly of a high field open magnet, which magnet includes a first upper magnet assembly, a lower second magnet assembly and at least one non-magnetizable support beam therebetween. The mechanical stabilizer-tuned damper reduces the dynamic response of the magnet. A connecting device is provided which consists of a threaded rod mounted to an attachment bracket through a linear bearing and vibration mount. A series of non-magnetic and extremely low conductivity plates of various weights are attachable to the rod to change the mass and the tuning frequency of the damper. The location and size of the mechanical stabilizer-tuned damper are determined to balance the frequency of the field oscillation and physical room. The direction of orientation depends upon the direction of motion to be dampened or controlled.

Abstract: An apparatus for supporting a patient support bridge member in an MR system where a first end of the bridge is supported by an upright support member on a first side of an MR imaging bore and the bridge extends through the bore so that a second end of the bridge extends out a second side of the bore, the apparatus including a bracket mounted to an MR main magnet on the second side of the bore and extending upwardly to contact and support the bridge there above.

Abstract: Apparatus is provided for reducing the level of acoustic noise or energy which is received by an imaging subject located within the bore of an MR imaging system. The apparatus comprises a bridge fixed within the bore to support the subject during MR data acquisition, and further comprises a curved frame, usefully formed of fiberglass, which is removably insertable in the bore for placement upon the bridge. The frame, when in place upon the bridge, defines a space within the bore which is disposed to receive the imaging subject. The frame is covered by a layer of material, such as open cell foam, which is capable of absorbing substantial amounts of acoustic energy present in the bore. At the same time, the material is highly transmissive to RF signals required for MR data acquisition and avoids spurious RF signal generation which would add noise to MR data.

Abstract: A magnetic resonance imaging device has a compensation circuit for compensating for magnetic disturbances therein. The compensation circuit includes a sensor for sensing magnetic field changes and generating a magnetic field change signal. The sensor is coupled to a control circuit that has a transfer function therein. The control circuit is used to generate a compensation signal in response to the magnetic field change signal. The compensation signal may be coupled to the compensation coils located by the first magnet portion and the second magnet portion of the device. Also, the compensation signal may produce a time-dependent bias or change the center frequency to cancel magnetic disturbances.

Abstract: Apparatus which provides a barrier for vibrational energy between an MR imaging system and an associated horizontal support surface includes a stiff platform of substantial mass, which is disposed to carry the entire weight of the MR imaging system. The apparatus further includes a number of vibration isolation elements positioned to support the platform and the MR imaging system upon the horizontal support surface. Each of the isolation elements comprises an enclosure containing pressurized air which is disposed to dampen vibrations, in order to oppose the transmission of vibrations between the platform and the support surface. An air pressure regulator is coupled to respective isolation elements to maintain specified air pressure levels therein, in order to support the platform in selected spaced-apart orientation with respect to the horizontal support surface.

Abstract: In an MR system, a mounting assembly is provided at each end of the bore of the main magnet for supporting a cylindrical gradient coil assembly within the bore. Each mounting assembly comprises first and second brackets, the first bracket being provided with a concave bearing surface having a specified curvature. The first bracket is fixably joined to the main magnet proximate to the lower side of the bore, and the second bracket is provided with a convex bearing surface which is selectively similar to the curvature of the concave bearing surface of the first bracket. The second bracket is attached to a lower portion of the gradient coil, so that the convex bearing surface extends longitudinally outward from the gradient coil assembly. A vibration attenuator is positioned between the convex and concave bearing surfaces of each mounting assembly, the vibration attenuator acting to transmit a static force between the two bearing surfaces to support the gradient coil assembly within the bore.

Abstract: The shock isolation system for CT equipment or the like employs a C-support holding isolation unit on either side of a support plate for the CT machine. Each isolation unit is made up of an elastomeric tube capped by a diaphragm and enclosing an air-tight volume. Different spring constants are produced by the isolation unit depending on whether only the diaphragm or the entire tube is compressed, allowing effective vibration isolation and shock protection for the supported equipment. The elastomeric tube provides both axial and lateral isolation eliminating the need for isolation units along multiple axes.

Abstract: A probe for measuring the displacement between the outer supporting wall of a cryostat and the inner magnet coil form employs magnetically balanced strain gauges attached to a beam with one end fixed to the cryostat wall and the other end held by the magnet coil form. The magnetically balanced strain gauges comprise two superimposed strain gauges with countervailing current flow. In one embodiment, two sets of gauges are attached in conventional bridge arrangement to provide temperature compensation.