Abstract: Detectors (20) of a CT scanner (10) have a radiation receiving face (34) which is larger than a photosensitive face (30) of a photodiode (22). Lead wires (28) connect the ends of the diode photosensitive surface to terminals (26). A scintillation crystal (32) has an overhanging portion (38) which overhangs at least the interconnection between the lead wires and the photosensitive face to protect the adjoining areas of the photosensitive face from incident radiation. This enables the radiation receiving surface to be larger than the photosensitive surface. The crystal is either undercut to define the overhanging area or a section of light pipe (60) is provided between the photosensitive surface and the crystal. Increasing the radiation receiving face decreases rotor ripple artifacts. Decreasing the photosensitive face area decreases diode capacitance and increases resistance which improves amplifier performance.

Abstract: A patient couch assembly (B) supports a patient such that a nuclear camera system (A) can scan the patient in either (i) a longitudinal mode or (ii) a transverse tomographic mode. A table top (20) is connected adjacent one corner with an undercarriage (30) that supports the table top above the floor. Generally vertical supporting portion (34) is connected only adjacent an intersection of a first side and a foot end (22) of the top (26). This enables a camera head (10) of the nuclear camera to move peripherally around a transverse central slice of the patient and the associated support position of the table top or to move longitudinally completely along the underside of the patient and table top from head to foot.

Abstract: A proximity type image intensifier having an evacuated electrically conductive tube envelope is described. The image intensifier tube includes improved structure for supporting components within the tube envelope. The support structure includes a support ring having a first inwardly extending edge portion which defines a support surface for supporting the component, and a second inwardly extending edge portion which defines a compression surface and component access aperture. The retaining ring includes a planar inner surface and an outer edge surface. The inner surface contacts the component supported in the support ring. The retaining ring is allowed to expand whereupon the outer edge surface engages the support ring compression surface. Radial expansion of the retaining ring creates an axial compression force between the retaining ring inner surface and the support surface about the circumference of the component being supported.

Abstract: A film processing fluid mixing and dispensing apparatus is disclosed having means for flushing residual chemicals from surfaces of the apparatus. The apparatus has a reservoir for mixing chemicals and a structure for delivering water under pressure to the reservoir. The apparatus also includes several bottles each containing film processing chemical components. The bottles each have a mouth which is sealed with a piercable septum. A stationary template is provided for stationarily engaging and supporting the inverted bottles so that fluid from them drains into the reservoir. Movable piercers are provided for piercing the septa. The piercers are tubular. An elongated nozzle is fitted into each piercer core for delivering water under pressure to the inside of the reservoir and to the piercer surfaces. The nozzles are equipped with defusers to deliver the water in a divergent spray. The nozzles are held stationary, while the piercers are mounted for relative longitudinal movement with respect to the nozzles.

Abstract: A first electromechanical transducer (40) generates a first electrical signal indicative of rotation of a ball (A) relative to a first axis. A second electromechanical transducer (50) generates a second electrical signal indicative of rotation of the ball relative to a second axis. A third electromechanical transducer (60) generates a third electrical signal indicative of rotation of an annular ring (12) around the periphery of the ball, i.e. a third axis. A resolver circuit (D) converts the first, second, and third electrical signals into an indication of movement or position along the first, second, and third axes.

Abstract: A xenon gas system (B) introduces xenon gas into a patient's blood. The xenon concentration in the patient's blood is monitored (26) periodically as the concentration builds toward a saturation level (32). The absorption data is divided into at least three curved segments (32, 34, 36) each of which are approximated by a curve segment to determine absorption curve characteristics. The amplitude of the saturation curve segment is determined as first characteristic; the slope of the second curve segment is a second characteristic; and an end amplitude and time constant of an exponential third curve segment provide third and fourth characteristics indicative of blood xenon absorption. A CT scanner (A) generates a plurality of time displaced image representations, each of which is subtracted (52) from a reference image (30) to determine difference image representations. Each image representation includes a plurality of pixels that correspond to subregions of a region of interest within the patient.

Abstract: A radiographic imaging system and method is disclosed having improved monitor control for enhancing the flexibility of a monitor so that one monitor can perform optimally under several system operating modes. The monitor automically detects the line rate most suitable for producing an image in the selected mode. Brightness compensation is accomplished as a function of the scan line rate at which the monitor is operating. Aspect ratio of the monitor produced image is also adjusted automatically in accordance with the operating mode selected. The system incorporates monitor brightness adjustment as a function of aspect ratio as well. Where the system incorporates a video tape or disk recorder, a time constant of the monitor is adjusted to optimize the monitor's compatibility with the video data output from the recorder in response to the selection of an operating mode wherein the recorder feeds the monitor with video information.

Abstract: A gradient field controller (30) generates current pulses with a preselected profile. Eddy current compensation circuits (42) alter the current pulse profile by adding additional components of selectable frequencies with selectable amplitudes or gains. A power amplifier (32) amplifies the modified current pulse and applies them to gradient field coils (34) of a magnetic resonance imager. A probe or coil (50) monitors the induced gradient response which is integrated (52) to provide an electronic representation of the induced gradient profile. A least squares analysis routine (72) determines the time constant and amplitude of a component attributable to a first eddy current which degrades the induced gradient profile. A filter frequency correction factor calculating routine (76) calculates appropriate filter frequency settings and a gain calibration factor calculating routine (78) calculates the gain settings for the compensation circuits (42).

Abstract: A computerized tomographic scanning apparatus comprises a gantry assembly for performing tomographic examination and including a detector and data acquisition assembly carried on a first frame for selective rotation about a first axis. A base frame supports the first frame for limited tilting movement about a second axis which lies in a plane generally perpendicular to the first axis. A selectively operable drive assembly for tilting the gantry assembly about the first axis comprises first and second extensible and retractable rotary drive screw assemblies connected between the first frame and the second frame at locations spaced laterally outwardly on opposite sides of the first axis. Each drive screw assembly includes a first end connected to the base frame and a second end connected to the first frame at a point radially outwardly of the second axis.

Abstract: A system and method is disclosed for minimizing residual vibration of a radiographic system due to rapid movement of a radiographic film cassette between a park and expose position. The cassette is moved by a servo system including a servo motor which is responsive to a voltage input waveform to drive the cassette. A waveform is chosen for the voltage input such that no inpulse derivatives appear until the waveform has been diferentiated at least three times. The primary natural resonant frequency of the system is determined and noted. The duration of the selected input waveform is adjusted such that the frequency spectrum of the adjusted input waveform defines a relative null which approximately coincides with the primary resonant frequency. The amplitude of the voltage input waveform is then further adjusted as a function of the distance to be traveled by the cassette between the park and expose positions.

Abstract: A tachometer (32) monitors the speed of a continuously moving web or article (12). A lens (20) focuses an image of a portion of the web in an examination region (14) on image section (22) of a CCD array. As the web moves, the image moves correspondingly along the image section. A synchronizing circuit (C) adjusts the frequency of the tachometer output signal and uses it in lieu of a fixed frequency oscillator as the master clocking or timing basis for generating clocking pulses for the CCD array. More specifically, the synchronizing circuit generates four phase clocking pulses (.phi.1A-.phi.4A) which shifts lines of CCD data along the image section at the same speed that the image is moving along the CCD section. In this manner, the pixel values integrate light from the same area of the imaged web at each shifted position along the image section.

Abstract: A resonance exciting coil (C) excites magnetic resonance in nuclei disposed in an image region in which a main magnetic field and transverse gradients have been produced. A flexible receiving coil (D) includes a flexible plastic sheet (40) on which one or more loops (20) are adhered to receive signals from the resonating nuclei. Velcro straps (46) strap the flexible sheet and the attached coil into close conformity with the surface of the portion of the patient to be imaged. An impedance matching or coil resonant frequency adjusting network (50) is mounted on the flexible sheet for selectively adjusting at least one of an impedance match and the peak sensitivity resonant frequency of the receiving coil. A preamplifier (52) amplifies the received signals prior to transmission on a cable (24). A selectively variable voltage source (70) applies a selectively adjustable DC bias voltage to the cable for selectively adjusting at least one of the impedance match and the LC resonant frequency of the receiving coil.

Abstract: A thin dielectric sheet (36) has a first or loop coil (30) defined on one surface thereof and a second or Helmholtz coil (32) defined on an obverse surface thereof. The dielectric sheet and associated coils may be laid flat (FIG. 3) or bent to match a selected curved surface of the subject (FIGS. 6-8). The first and second coils are arranged symmetrically about an axis or plane of symmetry (34). The first coil has an associated magnetic field along a y-axis and the second coil has an associated magnetic field along the x-axis. Circuits (40 and (42) tune the first and second magnetic resonance coils to a preselected magnetic resonance frequency. Magnetic resonance signals of the selected frequency received by one of the coils are phase shifted 90.degree. by a phase shifting circuit (50) and combined with the unphase shifted signals from the other coil by a combining circuit (52). The combined signals are amplified (54) and conveyed to electronic image processing circuitry (E) of a magnetic resonance scanner.

Abstract: A scan frame (12) is mounted to a stationary frame (10) for rotation about a scan circle (14). A two speed resolver (20) has one circular core (36) mounted to the gantry and another circular core (32) mounted to the stationary frame. A primary winding (30a, 30b) on one of the cores receives AC excitation power from an excitation generator (58). Quadrature coarse resolution windings (54, 56) and quadrature fine resolution windings (50, 52) both in quadrature produce output signals indicative of the relative angle of the scan frame to the stationary frame. An angular position digitizing circuit (60) converts the analog sine/cosine signals into a digital angle signal.

Abstract: An incomplete set of magnetic resonance image data is collected and stored in a view memory (40). The incomplete set of image data includes a central or first set of data values (42, 42') and half of the remaining data values (44, 44'). A symmetric data set which fills the other remaining half (46, 46') of the data values is generated (90) by determining the complex conjugate of each value of the incomplete data set. The incomplete and symmetric data sets are Fourier transformed (64, 94) to create first and second images f.sub.1 (x,y) and f.sub.2 (x,y). The first and second images are multiplied (100, 104) by conjugately symmetric phase correction values e.sup.i.phi.(x,y) and e.sup.-i.phi.(x,y) from a phase correction memory (70) to produce phase corrected images. The first and second phase corrected image representations are summed (110) and displayed (114). The phase correction values .phi.

Abstract: An x-ray imaging system incorporating a television imaging chain is disclosed. The system includes automatic gain control circuitry, operable upon the video signal produced by the camera of the television imaging chain. The gain control circuitry affords automatic gain control capability for increasing the video gain in response to an undesired decrease in video output signal level. The gain control circuitry, however, is constrained in that it includes circuitry for establishing a minimum video gain which is always maintained during a study, irrespective of increases in brightness of an overall sample window area of the image, which could otherwise cause undesirable darkening of areas of interest in the image when the sample window also includes uninteresting structure which happens to exhibit a bright field.

Abstract: A radiographic apparatus (10) includes an x-ray tube (16), an off-focal radiation collimator (20), a shutter (22), and a primary beam defining collimator (24) between the x-ray tube and patient receiving region (14). The off-focal collimator is mounted within a collar (48) which surrounds an x-ray port (36) of the x-ray tube. The tube port is sealed from the atmosphere by an aluminum window (46). A plate (62) of a radiation blocking material is rotatably mounted by a bearing (70) within the collar closely adjacent the aluminum window. By rotating the moveable plate, aperture or radiation passing slots or portions (62, 64) of different sizes are selectively brought into alignment between a focal spot (34) of the x-ray tube and a radiation passing region or slot (52) of a stationary plate (50) at the distal end of the collar. The aligned slots block the passage of off-focal radiation. Moreover, rotating slots of different sizes into alignment changes the size or angle of the x-ray fan beam.

Abstract: An x-ray tube is enclosed in a housing 14, with a detachable x-ray cone 22 having an outward extending flange member 42, a cone holder 18 for receiving the flange member 42, a latch button 50 projecting from the holder for selectively releasing the cone 22 from the holder 18, and a safety plate assembly 26. The safety plate assembly is mounted between the cone holder and the housing 14 and has first and second tabs 28 which project from a periphery of a planar portion 30 of the safety plate substantially at right angles therewith. Each tab 28 has a projection 34 that is directed inward toward the other end generally at right angles with the tabs whereby a resting place is provided for the released cone 22 until the cone is manually removed.

Abstract: As an object moves along a conveyor (A), a position sensor (B) generates a trigger signal. The trigger signal causes a strobe (14) to emit a high intensity flash of light into an examination region. A lens (20) of a CCD camera (C) focuses light from the examination region both before and during the flash on an image section (24) of a CCD array (22). Subsequent to the flash, a trigger signal delay circuit (16) causes a control circuit (D) to shift the lines of pixel values from the image section into a storage section (26), from the storage section to shift registers (32), and serially from the shift register as a video signal. A video signal channel (52) refines the video signal which is transferred to a computer system (E) which implements a preselected quality control algorithm selected in accordance with a product to be examined.

Abstract: An artifact inducing image acquisition mapping system and technique is described for use in connection with digital imaging. A gray scale mapping technique is employed to indicate to an operator the brightness function of each pixel of an image. Where the brightness function is less than 95% of saturation, the image is displayed normally. Where the brightness function is at least equal to the saturation full scale value, that portion of the image is displayed in total black. Where the brightness function is between 95% and 100% of saturation full scale value, the image portion is displayed as mixed dark and light, i.e., a speckled region. An alternate embodiment simply displays saturated regions to total black.