Abstract: A quench protection circuit for the series connected but spatially separated magnet coils of a superconducting magnet utilizes a parallel circuit of multiple heaters and reverse connected diodes shunting portions of the series connected magnets coils with the heaters physically positioned in thermal contact with other coils in the series circuit to thermally transfer a heat quenching action in any coil to all coils, along with a shunting current through the diodes to shunt peak currents upon coil quenching to avoid undesired spot temperature rise and enable controlled quenching of the entire magnet upon quenching of any coil.

Abstract: An insertion and positioning mechanism to assist in inserting the cryocooler into the sealed cavity of a recondensing superconducting magnet during superconducting operation utilizing guide assembly and slider assembly combinations to resist forces of cryocooler interaction with the magnetic field of the superconducting magnet to avoid misalignment, and to ensure good thermal contact at the cryocooler thermal interfaces.

Abstract: A repairable compact ultrasound probe which is easy to assemble and disassemble, and which has cable load transfer and heat dissipation capabilities. The transducer assembly of the probe has a heat-conductive backing board which is fastened to a yoke incorporated in the cable assembly. The cable assembly further has a strain relief element which is secured in a separate operation following attachment of the yoke to the backing board. When the strain relief element is secured, the probe handle is compressed between the strain relief and a headshell of the transducer assembly, thereby forming a housing. To disassemble the probe, the strain relief is turned counterclockwise with respect to the transducer, thereby releasing the handle and allowing access to the probe interior.

Abstract: A nuclear medical imaging system generates transmission and emission images simultaneously. The system includes a gamma camera and a linear transmission source disposed on opposite sides of an imaging region in which a patient lies. A plurality of views are taken at different rotational angles around a patient. At each angle, the view acquisition period is divided into two segments based on whether the transmission source is on or off. Emission image data is acquired either in both period segments or only while the transmission source is off. The transmission image data is acquired when the transmission source is on, and crosstalk image data is acquired when the transmission source is off.

Abstract: The present invention, in one form, is a system which, in one embodiment, utilizes signals from a detector array to verify system dose. More specifically, the detector array signal intensities are used to determine image noise and a collimator aperture to verify an x-ray dosage. Particularly, in one embodiment, the signals intensities from the detector array are used to determine the position of collimator cams. Using the position of the collimator cams, the aperture of the collimator is determined so that X-ray dose may verified using the collimator aperture and image noise information.

Abstract: An ultrasound imaging system having an adaptive spatial filter the filter coefficients of which, for particular image parameter sample, are determined by counting the number of neighboring image parameter samples having zero or near-zero values. If the number of zero or near-zero values in a data window is greater than a predetermined threshold, the data in the window is passed, not filtered. This filter has two advantages over other spatial filters. First, image parameter data samples having only zero or near-zero neighboring values (i.e., isolated "point noise") are not smeared. Second, boundaries such as the edge of color in a vessel (where the surrounding area is black, i.e., the color image parameter values are zero or near zero) are not smoothed as much as in conventional filters, preserving the sharpness of the edge.

Abstract: Methods and apparatus of correcting image data for z-axis non-uniformity in a computed tomography (CT) system are described. In one embodiment, the CT system includes a configurable multislice detector array and a calibration algorithm. In accordance with one embodiment of the algorithm, output signals from a plurality of detector cells are sampled to generate an x-ray beam z-axis non-uniformity profile. The x-ray beam z-axis profile is then used to determine a detector z-axis non-uniformity profile for the detector array. Utilizing the z-axis profiles, the output signals from the detector cells may be calibrated to reduce z-axis non-uniformity errors.

Abstract: A method for configuring an ultrasound imaging system having a programmable signal processor and an operator interface. Application codes for programming the signal processor to process signals in accordance with respective imaging modes are stored in memory. A user operates an operator interface to select one of the plurality of imaging modes. The master controller programs the signal processor with the application code corresponding to the selected imaging mode. The signal processor is programmable to process signals in the B mode, M mode, color flow imaging mode and Doppler imaging mode. Preferably, the programmable signal processor is an array of digital signal processor chips. Incoming vector data is partitioned amongst the respective digital signal processor chips. The processed vector segments are then recombined to form a vector of image data for display.

Abstract: The present invention deals with the catalytic hydrogenation of fluid used to cool and dielectrically insulate an x-ray generating device within an x-ray system. According to the present invention, a method and apparatus are provided for hydrogenating fluid that has been exposed to x-rays to reduce the amount of H.sub.2 gas, free hydrogen atoms and unsaturated molecules in the fluid. The method comprises exposing the fluid within the x-ray system to a catalytically effective amount of catalyst. The catalyst operates in temperatures in the range of about 10-300.degree. C. and pressures in the range of about 0.1-30 atmospheres. The catalyst may comprise a solid, non-soluble catalyst, a soluble catalyst, or a combination of both. A suitable solid, non-soluble catalyst comprises Group VIII elements and their compounds. Group VIII elements comprise iron, cobalt, nickel, ruthenium, rhodium, palladium, osmium, iridium and platinum. The catalytically effective amount of solid catalyst ranges from about 1-100 cm.sup.

Abstract: A method and an apparatus for displaying an ultrasound image comprising a region of interest (ROI) having an optimal image quality and a background region having a normal image quality. In the displayed image the background region lies outside the ROI. The optimal image quality within the ROI is achieved by using a set of imaging parameters which are different than the set of imaging parameters used to acquire the background image, including one or more of the following: different (e.g., shorter) transmit waveforms, an increased number of transmit focal zones per unit depth, different transmit and/or receive apertures, different center frequencies for the receive bandpass filter (primary and/or (sub)harmonics), and higher vector density (i.e., decreased vector spacing). Since the optimal imaging is restricted to a ROI, a high frame rate is still possible within the ROI depending on its size.

Abstract: An architecture in which a plurality of delay calculators are distributed throughout the beamformer. Each delay calculator provides beamforming delays and apodization values for a plurality of channels/elements. The delay calculators are initialized with element position coordinates. Then, while imaging, focal coordinates and steering angles are broadcast to all delay calculators. The delay calculator uses a cordic rotator to perform the aperture projections and calculate the hypotenuse. The cordic rotator performs successive coordinate transformations, in two dimensions, using coefficients that are simple powers of two. The resulting apodization values and time delays are then provided by a channel control bus to a plurality of channels.

Abstract: A method and an apparatus for compensating for fully or partially inoperative elements in an ultrasonic transducer array. The inoperative elements are compensated for by "bridging" or "shorting" them to fully operative elements. This compensation technique can be applied to one-dimensional or multi-dimensional transducer arrays. A bridge between a fully or partially inoperative element and an adjacent fully operative element can be achieved by physically shorting the elements somewhere in the signal chain or by electrically connecting the elements via switches, e.g., of a multiplexer. The state of the multiplexer switches (i.e., open or closed) is controlled by loading MUX State control data into a flash memory located on-board the probe. This MUX State control data includes switch settings for connecting a defective element to an adjacent fully functional element in the transducer array.

Abstract: Scintillators having a geometric configurations that substantially prevent x-ray beams from passing entirely through a gap between adjacent scintillators are described. More particularly, if the scintillators are cut on an angle to form parallelogram or trapezoidal shapes, or if the detector module is tilted in the x-ray beam z-axis, an x-ray beam will not pass through a non-scintillating gap between adjacent scintillators over the range of focal spot positions. Such scintillators have an increased geometric efficiency compared to known scintillator constructions.

Abstract: A computerized imager is programmed with software that allows properly formatted image frames (objects) to be sent to one or more remotely located devices selected from a list of configured devices. For each job selected for transfer to a remote device, an element is added to a linked list which forms a virtual queue, each element incorporating a respective pointer (i.e., the file name) identifying each stored image to be included in that particular job. Each element identifies the image frames included in the job and the destination remote device for that job. Elements for failed jobs are transferred to a Holding Queue. An interactive display menu enables the operator to easily redirect the failed jobs to a secondary remote device by clicking on the menu.

Abstract: An x-ray transmissive window assembly for use in metal framed x-ray tubes is formed of at least two layers of metal joined by explosion welding. An x-ray transmissive window, preferably comprising aluminum or an aluminum alloy, is joined to a transition layer, which is typically the same material as the x-ray tube vacuum vessel, to form the transmissive window assembly. The transmissive window is formed in the assembly by removing the transition layer material from the central region. A weld flange is prepared by removing the x-ray transmissive window material from the periphery of the assembly. The assembly is then welded into the x-ray tube vacuum vessel using traditional techniques. In another embodiment, a multi-layered window assembly comprises an x-ray transmissive window, a transition layer weldable to an x-ray tube vacuum vessel, and an intermediate layer that acts as a mask or aperture to attenuate peripheral radiation and clearly define the edges of the transmitted x-ray beam.

Abstract: A method and an apparatus for automating the B-mode transmit waveform center frequency/length adjustment based on actual image data. The average SNR and the spatial correlation statistics in selected kernels of the image data are analyzed to test if high-quality signal is present. By placing one or more of the test kernels at relatively great depth (i.e., close to the bottom of the user-selected image depth range), the overall test results indicate the highest-resolution transmit waveform that can be used, while providing a sufficiently strong signal down to the desired depth.

Abstract: A pressure relieving venting system for a liquid helium superconducting magnet to vent cryogen gas upon a magnet quench including a burst disk closing the venting system during normal superconducting operation and sandwiched between a peripheral gasket assembly maintained under constant pressure by a plurality of axially extending bolts, spring washers and nut assemblies to preclude helium gas leakage in the absence of the disk bursting under excessive pressure.

Abstract: A method and apparatus for performing harmonic imaging. Each transmit focal zone in the near-field is interrogated by two or more transmit firings of different phase, while each transmit focal zone in the far-field is interrogated by a single transmit firing. On receive, the respective near-field vectors are summed, thereby substantially canceling the fundamental signal components while isolating the (sub)-harmonic signal components. In the far-field, the single transmit firing has a fundamental frequency .function..sub.0. A filter isolates the signal component having a passband centered at a (sub)harmonic frequency, e.g., 2.function..sub.0. The near-field and far-field receive vectors at each scan angle are then stitched together to form a composite vector.

Abstract: A method and an apparatus for automating time-gain compensation (TGC) and lateral-gain compensation (LGC) based on the B-mode image data. The automatic gain adjustments are aimed at equalizing the mean signal intensities along the axial (for TGC) and/or lateral (for LGC) direction of the image, and suppressing any lateral band (for TGC) and/or sector (for LGC) that contains mostly noise. The automatic TGC/LGC adjustment method is implemented in software on a digital scanner and uses a noise model of the entire B-mode processing chain from the beamformer through the B-mode processor to the back-end video processor.

Abstract: A system for connecting a transducer array to a coaxial cable. A fanout flex circuit is electrically connected to the coaxial cable, to form one subassembly, and a transducer flex circuit is incorporated into a transducer stack in electrical connection with the transducer array, to form another subassembly. The fanout flex circuit has a row of terminals of first linear pitch at one end and a row of terminals of second linear pitch, less than the first linear pitch, at the other end. The terminals of first linear pitch are electrically connected to the wires of the coaxial cable. The terminals of second linear pitch are electrically connected to a row of free terminals of the same linear pitch on the transducer flex circuit. A layer of pressure-activated conductive adhesive is applied on one row of terminals and then the other row of terminals is pressed against the adhesive-coated row.