Abstract: A system for improving the performance of video cameras used in Digital Subtraction Angiography wherein the cameras have tubes comprising targets with elements in said target that correspond to pixels of an image. The method basically comprises the step of defocusing the electron beam especially during the scrubbing operation so that the electron beam impinges on more than one element at a time.

Abstract: An apparatus for examining a body by means of penetrating radiation. The apparatus has a source of penetrating radiation for transmitting radiation through a body, and a detector array disposed to detect the radiation after passage through the body. Radiation beams emitted by the source traverse a plurality of paths through the body and are detected by the detector. The source has at least two distinct point sources for emitting radiation. The distinct point sources of radiation alternately emit radiation. The detector array can be a reduced array of detectors which subtends less than the full reconstruction circle diameter. A method is provided for increasing the spatial resolution in a CT scanner by increasing the sampling density by interleaving radiation beams emitted by the radiation source between adjacent radiation beams continuously as the source and detectors are rotated about the body.

Abstract: An improved digital fluorographic system for displaying images of objects wherein the improvement is affected in the circuitry for log amplifying the video signal acquired of an object by base line clipping the amplified video signal to remove the chances of adverse results from the high rate of amplification for low input signals.

Abstract: A system and method are presented for reprojecting images generated by a back-projector. The image data is processed to distinguish hard and soft tissue and then is transmitted to the normal input of the back-projector. Pseudo-projections (reprojections) are obtained at the normal output of the back-projector. Each image row is fed into the input of the back-projector as a normal projection. The "image" generated by the back-projector is now one projection. In order to generate the required amount of reprojections "L", the image is supplied to the back-projector "L" times. Each time the image is presented with constants, such as the reprojection angle associated with the specific reprojection. The reprojections at the back-projector output are combined in a feed-back circuit with the original projections to correct for artifacts, such as polychromatic artifacts.

Abstract: A pseudo correlation system and method for determining matches between data defined shapes and templates by obtaining a pseudo correlation value without a successivity of multiplications or determining square roots.

Abstract: Systems and methods are presented for reprojecting images which comprise taking the two-dimensional Fourier transform of the image, interpolating the transform in order to obtain the values on radial lines, and taking the inverse one-dimensional Fourier transforms of the radial lines.

Abstract: An Rf coil arrangement for MRI systems wherein the electrical length is reduced to improve the S/N ratio and the Rf power efficiency.

Abstract: A magnetic gradient field generating arrangement comprising a pair of oppositely disposed hollow cylindrical current conductive segments having current flowing in the same direction in the segments with the segments oriented to generate magnetic gradients .gradient..sub.x =.differential.Bz/.differential.X.

Abstract: A medical imaging device employs a plurality of triggered plasma cathode flash X-ray sources, each of which has an axially extending round anode rod, a cathode, and a trigger electrode. The application of a trigger pulse between the electrode and the cathode produces a burst of plasma near the cathode, the plasma containing electrons that are accelerated toward and impact the anode in a region termed the "focal spot" for producing X-rays when a voltage source applies a predetermined voltage between the cathode and anode. According to the invention, a non-conducting surface interconnects the electrode with a cathode or a conductor held at the same potential as the cathode, the application of a trigger pulse to the electrode causing flashover across said surface for producing the burst of plasma.

Abstract: A digital fluorographic system for displaying images comprising video and multi format display means which are each provided image data from large size matrices (1024.times.1024). The data is compressed and is provided to the video display at speeds that preclude the necessity of using broad bandwidth equipment.

Abstract: A map of a radiation field produced by a gamma camera is corrected for three types of spatially dependent errors in a manner that corrects for each error independently of the others. The errors corrected for are dislocations which result from the non-linearity of the optics, photomultipliers and electronics of the camera, energy window variations resulting from inhomogeneity of the optical system which includes the crystal, light guide, and photomultipliers, and the non-uniform sensitivity of the head resulting from the non-uniform stopping power of the crystal and collimator of the camera head. The map is corrected by obtaining a set of correction factors associated with each type of error using a calibration technique that insures independence between the various correction factors, and applying the correction factors to the map obtained in a nuclear imaging process in a way that independently corrects the map for each type of error.

Abstract: A set of two-dimensional views of a body are provided from successive azimuthal angles with respect to a given axis. The set of views of the body are successively displayed on a display screen which shows the body as rotating about an axis. A point of interest in the body also appears to rotate about the axis. That view at which the point of interest is maximally displaced from the apparent axis of rotation is used to determine the angular position of the point of interest. The true displacement of the point of interest from the axis of rotation and its true displacement along the axis of rotation are available from that view. Thus, the cylindrical coordinates of the point of interest are known. To check the accuracy with which the coordinates of the point of interest have been determined, a cursor is established in the stopped view, and the projection of the cursor in the other views is calculated in a conventional manner.

Abstract: The system and method of the present invention minimizes artifacts caused by noncoplanarity between source and detector component in a computerized tomography system. The source component produces a beam of penetrating radiation which is rotatable about an axis and is incident on the detector component; and non-coplanarity is defined by the collection of the positions of the source component which defines a first plane, and by the collection of positions of the detector component which defines a second plane axially spaced from the first plane. Data obtained during a scan of a body located between the source and detector components are processed to form two images, one image being based on data related to one side of a focal plane interposed between the first and second planes, and another image being based on data related to the other side of the focal plane.

Abstract: A system is provided for transferring a series of images which are displayed successively on a screen of a video monitor using optical means, onto a photosensitive surface by juxtaposing successive elemental images to form a unique composite image. The composite image is directly created on the screen of the video monitor without the necessity of translationally displacing the various elements relative to one another to achieve the framing or to vary the magnification ratio. The composite image is created by successively sweeping various portions of the screen of a high-definition tube. The amplitude and the centering of the sweep signals are determined, as a function of the selected format, by converters run by programmable memories.

Abstract: A method and apparatus for high-speed ultrasonic imaging of very rapidly moving bodily structures. A transducer produces sequential data frames corresponding to sequential images of bodily cross-sections produced by periodically scanning a body with an ultrasound beam produced by the transducer. Reflected ultrasonic echo pulses are digitized and stored in a memory array in which each data frame is stored in a single segment of a plurality of memory segments which form the memory. The transducer periodically scans the body at a predetermined first rate, whereas the sequential display of the sequential data frames occurs at a second predetermined rate which is different from the first rate. The system permits acquisition of data at a rate which is greater than the perception rate of the human eye and display of the acquired data at a rate which can be visualized by a human observer.

Abstract: A method for using a gamma camera having a head including an array of photodetectors that produces a group of input pulses in response to an actual interaction of a radiation stimulus with the camera head, includes the step of repetitiously generating groups of synthetic pulses that resemble groups of input pulses and simulate the occurrence of synthetic interactions of stimuli with the head. These groups of synthetic and input pulses are applied to processing circuitry that produces groups of processed pulses. The coordinates of both actual and synthetic interactions based on said processed pulses are computed; and a representation of the spatial locations of both actual and synthetic interactions based on the computed coordinates is stored.

Abstract: A plasma electron source has an apertured cathode, and a housing for defining a cavity behind the aperture. A trigger electrode, in communication with the cavity, is responsive to a short-duration trigger pulse for establishing plasma in the cavity. The plasma is sustained in the cavity subsequent to the termination of the trigger pulse by a bias circuit, which biases the cavity at a relatively low voltage with respect to the cathode for a period of time much longer than the duration of the trigger pulse.

Abstract: Equipment and methods are presented for rearranging divergent beam derived data into parallel data to enable decreasing the number of preprocessing computations and improving the quality of the resulting tomograph. The equipment and method comprise means and steps which vary the spacing of at least portions of the resulting parallel projections, so that when the parallel projections with varied spacings are combined with the parallel projections that have not had their spacing varied, the cupping artifacts normally present when using projections obtained from rearranging are cancelled.

Abstract: A sector-scan ultrasonic imaging apparatus includes a biopsy attachment mounted on the housing of the imaging apparatus for positioning a biopsy needle relative to the ultrasonic scan head of the imaging apparatus. An image display device displays both an image of the region scanned by the scan head and a predetermined, superimposed electronic representation of the position of the biopsy needle-line relative to the probe scan head. The biopsy needle-line is calibrated with a scan head coordinate system which defines a sector sweep of the scan head by determining the coordinates of the needle-line in the scan head coordinate system independently of determining the particular spatial relationship of the needle-line in operative position relative to the scan head. A calibration member adapted to be mounted on the biopsy attachment includes at least two ultrasonic reflection regions which are scanned by the scan head during the calibration mode and displayed on an image display device.

Abstract: A medical diagnostic imaging system that selectively digitizes and processes video data obtained from either a radiographic or a fluorographic source.