Abstract: Method and apparatus is disclosed for providing a beam of X-radiation having an intensity value which is rapidly switchable between nonzero levels. An X-ray tube having one or more electron-emitting thermionic filaments is provided with cathode bias control circuitry for limiting electron flow between the tube's cathode and anode structures. The bias control circuitry applies one of a plurality of predetermined values of negative potential to a cathode cup structure for allowing predetermined quanta of electrons emitted from an energized filament to reach the anode.One value of the negative potential bias is a relatively large value for cutting off all flow of electrons; a second or intermediate value of negative voltage bias allows a predetermined fraction of the total quanta of emitted electrons to flow; and a third potential value allows a greater number of electrons to flow.

Abstract: An X-ray tube comprises a rotatable anode supported by a bearing structure having portions lubricated by lead. The bearing structure includes a grooved outer race which is coated with ion-implanted lead, an inner race comprising a grooved portion of a spindle, and a plurality of lead-burnished balls disposed between the races.

Abstract: An X-ray tube includes a rotor body having an outer sleeve of copper and an inner sleeve of steel, the two sleeves being joined by brazing. A black coating is applied to the outer surface of the copper sleeve and the inner surface of the steel sleeve, as well as to the outer surface of a copper bearing housing concentrically disposed within the rotor body. A steel spindle is concentrically and rotatably supported within the housing by a bearing structure and is rigidly affixed to the rotor body to support the rotor body for rotation. The X-ray tube also includes an anode comprised of molybdenum having a coating of rhenium-tungsten. The anode is supported on a shaft comprised of a material having a low coefficient of thermal conductivity such as niobium, an alloy of niobium, molybdenum, or an alloy of molybdenum. The X-ray tube further includes a bearing structure having portions lubricated by lead.

Abstract: An X-ray apparatus which is readily convertible for conventional radiographic or tomographic operation includes an X-ray source and an imaging device movably supported on opposite sides of a patient support. For tomographic procedures, the source and the imaging device are interconnected by shielded drive system components to effect coordinated movement of the source and the device. For conventional radiography, the drive components are disconnected to permit independent movement of the source and the imaging device. The drive components are disconnected for conventional radiography by lowering the X-ray source and by operating a latch located near the imaging device. The drive components are connected for tomography by raising the X-ray source and by operating the latch. Other improvements such as the use of rotary encoders to provide a digital readout of the location of a tomographic examination plane and to control the operation of the source during tomographic procedures are described.

Abstract: A serial radiograph system has an improved film changer featuring reusable film pack containers. An exposure station through which X-rays are directed is virtually free of X-ray absorbing material providing a "see through" station. As a consequence of the "see through" exposure station, an image intensification tube positioned under the exposure station provides an unobstructed fluoroscopic image with minimum X-ray dosage to a patient.The film changer utilizes film packs, each of which has a semienclosed, partially sealed, pouch. Each pouch contains a sheet of radiographic film between a pair of intensifying screens. A plurality of the film packs are stacked in a novel supply magazine and are sequentially transported to the exposure station by a transport system having a plurality of pinch roll pairs.

Abstract: An improved method and apparatus for transaxial tomographic scanning of a patient. A scanning system is provided having a rotatably mounted X-ray radiation source/detector pair which orbits and radially scans the patient in the plane of orbit. The source provides a plurality of beams of radiation having axes in the orbital plane. The beams pass through the patient to an array of detectors each of which is aligned with one of the beams. Radiation intensity data is collected at predetermined orientations of each beam/detector pair as the assembly orbits about the patient. In a preferred embodiment the rotatably mounted source-detector pair is rotated as a unit through a preselected rotation angle .phi. about an axis effectively passing through the source. The axis and the source-detector pair connected to it are then orbited around the patient through an orbit angle .gamma. while maintaining the preselected rotation angle .phi.. The axis is orbited about an origin lying in the orbital plane.

Abstract: A dual filament, rotary anode X-ray tube generates X-radiation of extraordinary uniform cross-sectional intensity by focusing a pair of electron flows on a target to produce partially overlapping focal spots. A pair of electron-emitting filaments are independently and adjustably excited for producing the flows of the electrons, each of which produces a line focus-type focal spot. The filaments are positioned in respective focusing cups which are configured and electrically biased to provide a degree of focal-spot overlap which produces a uniform distribution of electrons on the combined focal spots. The uniform electron distribution on the combined focal spots produces a uniform distribution of emitted X-radiation.In another embodiment the electrons from the respective filaments are focused to provide radially aligned and adjacent inner and outer focal spots on the target. The flow of electrons to the outer focal spot is more heavily concentrated than the flow to the inward focal spot.

Abstract: Apparatus and method are disclosed for detecting excess strain or failure in a main cable interconnecting a movable tower and counterweight assembly in a tiltable X-ray table. A secondary cable, substantially parallel to the main cable, is provided for supplementing the force exerted by the main cable structure between the tower and counterweight to a degree which is a function of the amount of strain occurring in the main cable. Changes in the amount of supplemental force provided by the secondary cable are sensed and used to produce an indication of the main cable strain. A supplemental force indication is accomplished by structure for holding a portion of the secondary cable in a transversely deflected position and by a spring actuated limit switch coupled to the deflected portion. The limit switch produces an indication in response to forces transverse to the length of the secondary cable exerted in the deflected portion, which forces result from increased tension on the secondary cable.

Abstract: An apparatus and method is disclosed for producing photographs and bright fluoroscopic television pictures of radiation patterns from a subject as converted to visible light images by an image tube. The apparatus includes a radiation source for directing X-radiation through a subject, and an image tube for receiving that radiation and producing in response thereto a visible image of the pattern of such radiation impinging upon the image tube. The apparatus also includes a film camera and a television camera for viewing the image tube output. A diverter apparatus controls the selective transmission of the light image from the image tube onto the film camera and television camera.The film camera is directly aligned with the image tube output. The television camera is transversely displaced with respect to the image tube output. The diverter directs light from the image tube to the television camera in bursts syncronized with the field repetition rate of the television camera.

Abstract: An X-ray apparatus including a telescopic column support comprising concentrically positioned tubular sections nested one within another. Each of the sections except the innermost section has three guide bars triangularly spaced on the inner surface. Each section except the outermost section has rollers on the outer surface cooperating with the adjacent guide bars of the surrounding section. The guide bars cooperate with the rollers in a generally circumferential direction rather than radially of the tubular members. Mounting plugs held in apertures of the telescopic sections by an interference fit locate the guide bars and rollers and provide mounting surfaces therefor. The plugs are initially insertable into the apertures with a clearance fit, when an appropriate temperature differential is established between the plugs and sections.

Abstract: A radiation imaging system and method is disclosed for producing an enhanced television image of diagnostic quality from a light image produced by a common image tube and corresponding to a pattern of penetrative radiation from a subject. A source directs radiation such as X-rays through the subject and the image tube converts the emergent radiation pattern to a corresponding visible light image at an output phosphor. A television apparatus including an image isocon pickup tube views the output light image at a tube input face by way of a lens assembly and converts the light image to electrical, including video signals. A television monitor reconverts the electrical signals to a visible television image of enhanced quality representing the pattern of radiation from the subject. The television monitor includes an improved cathode ray tube with a planar output face, a small focal spot, and improved phosphor.

Abstract: An improved radiation measuring and processing unit for a radiation scanning system precisely determines the average intensity of a beam of radiation as it impinges upon a radiation detector during a primary time period of predetermined duration. The unit computes the average intensity by detecting the average rate of a train of intensity representing pulses occurring during a secondary time period whose duration is determined according to the occurrences of the pulses within the primary time period. The system is preferably a transverse section, X-ray scanning system, and the radiation detector generates a data signal having a level indicative of the intensity of the beam of X-radiation after it passes through a subject. The measuring and processing unit includes a pulse generator, preferably in the form of a charge pump integrator, for converting the data signals into the train of data pulses having a repetition rate which varies according to the level of the data signal.

Abstract: A scintillation camera system including compensated delay line clipping circuitry for narrowing data representing pulses in the system without introducing base line undershoot and a restoring circuit for minimizing base line fluctuation of a data signal. The compensated circuitry includes a single delay line circuit for clipping an incoming data pulse having a relatively long trailing edge. A variable resistor is coupled with the circuit for controlling amplitude and polarity of the unclipped, incoming data pulse. A value of this unclipped pulse is controllably summed with the clipped pulse for correcting delay line attenuation and base line undershoot. The restoring circuit is combined with the single delay line clipping circuit for restoring the base line of the single delay line clipped pulses. The restoring circuit produces double delay line clipped timing pulses from the single delay line clipped waveform pulses.

Abstract: A transverse section tomography system has an ultra-high-speed data processing unit for performing back projection and updating. An X-ray scanner directs X-ray beams through a planar section of a subject from a sequence of orientations and positions. The scanner includes a movably supported radiation detector for detecting the intensity of the beams of radiation after they pass through the subject. The detector generates a series of scan data signals representative of the detected intensities. The data processing unit is coupled to the scanner and operates on the scan data signals to produce a set of filtered scan data signals representative of the contribution of each of the scan data signals towards reconstructing an image of the planar section of the subject.The data processing unit includes a scan storage section for retrievably storing the filtered scan signals in scan storage locations corresponding to predetermined beam orientations.

Abstract: A transverse section tomography system has an ultrahigh-speed data processing unit for performing back projection and updating. An X-ray scanner directs X-ray beams through a planar section of a subject from a sequence of orientations and positions. The data processing unit includes a scan storage section for retrievably storing a set of filtered scan signals in scan storage locations corresponding to predetermined beam orientations. An array storage section is provided for storing image signals as they are generated. The image signals are stored in array storage locations coordinated with a preselected array of points of the planar section. The image signals are each successively updated to eventually represent the density of the planar section at each of the selected array of points. The processing unit also includes array storage and scan storage address calculators.

Abstract: An X-ray apparatus includes a telescopic column support with concentrically positioned tubular sections nested one within another. Each of the sections except the innermost section has three guide bars triangularly spaced on the inner surface. Each section except the outermost section has rollers on its outer surface cooperating with the adjacent guide bars of the surrounding section. The guide bars cooperate with the rollers in a generally circumferential direction rather than radially of the tubular members. Mounting plugs held in apertures of the telescopic sections by an interference fit mount the guide bars and rollers. The plugs are initially insertable into the apertures with a clearance fit, when an appropriate temperature differential is established between the plugs and sections.

Abstract: A data derandomizer for use in a scintillation imaging system. The imaging system produces data signals representing radiation events and presents them to a continuously operating video tape recorder for recording and subsequent playback to an imaging apparatus. The recorder can accept the data signals only in discrete time slots. The digital signals are produced in response to radiation events occurring randomly in time and therefore also occur at random time intervals. A data stacking circuit provides for receipt and simultaneous storage of several data signals between the detector and the recorder, the storage being in priority levels according to the order of occurrence of the data signals. Inventory control circuitry controls the stacking circuit to present the data signals to the recorder synchronously with the time slots, notwithstanding the random occurrence of the data signals.

Abstract: An X-ray apparatus includes a spot filmer for feeding sheets of unexposed film one at a time into a vacuum evacuable assembly for exposure, and for returning exposed film sheets to an exposed film magazine. The spot filmer has a housing defining a light tight enclosure. The film magazines are insertable through a door into the housing and into a film feed mechanism. The film feed mechanism unlatches, opens and positions the magazines; feeds a sheet of unexposed film into the vacuum evacuable assembly; releases the film sheet so the assembly can position the film sheet for exposure; and closes the film magazines. An orthogonal drive system positions the vacuum evacuable assembly to expose selected film sheet portions, and returns the assembly to a retracted position. The film feed mechanism opens the magazines; feeds the exposed film sheet into the exposed film magazine; and closes the magazines. The structures of these several mechanisms are described.

Abstract: A nuclear imaging system includes an analog signal processor which features analog data derandomization for minimizing data loss due to pulse pile-up. A scintillation detector provides a sequence of analog data pulses to the signal processor, the data pulses characterizing the energy level and situs of respective radiation events striking the detector. The signal processor includes sets of novel peak detectors and of sample and hold circuits which are serially connected and are operated to derandomize or space the sequence of analog data pulses so that the system can process pulses corresponding to photopeak events occurring only 1.5 microseconds apart. The analog data pulses are stored in analog pulse form in the peak detectors and are selectively transferred into the sample and hold circuitry from which they are transferred to the display mechanism. The signal processor is multiplexed with several data input channels for accommodating dual isotope operation.

Abstract: A system and method are disclosed for sensing and controlling the operation of a transaxial reconstruction tomographic apparatus having a movable radiation source for directing radiation through a subject and a radiation detector movable synchronously with the source in an orbital path about the subject to detect radiation emerging from the subject.The system includes circuitry and apparatus including an optical incremental encoder for producing index signals indicating when the detector passes predetermined locations in its orbital path, a frequency multiplier is responsive to the encoder for producing other more frequent signals indicating by interpolation the relative location of the detector with respect to the locations delineated by the index signals. Processing circuitry produces signals defining the boundaries of segments of the orbital scanning path, according to a scan segment magnitude and orientation indicated by the computational apparatus.