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: An X-ray tube with an adjustable focal spot is provided wherein the focal-spot position can be moved along the anode and the focal-spot width can be changed by applying a small voltage to the cathode-bias cup. The cathode includes means integral with the cathode for deflecting the flow of electrons to selectable focal-spot areas on the anode in response to an external drive circuit. The cathode includes a filament for emitting electrons to impinge on the anode, and a cathode cup having first and second parts electrically insulated from each other. The filament is electrically insulated from at least one of the parts of the cathode cup. The electrical insulation between the first and second parts of the cathode cup can be provided by a gap therebetween. The device includes biasing means for applying a voltage between the filament and the cathode to control the size and position of the region of impingement of the electron beam on the anode. The anode can be rotatable with respect to the cathode.

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: 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: 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 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: 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: Radiation imaging apparatus especially suited for use in a computerized tomographic (CT) scanner employs an array of discrete X-ray sources, each being a cold cathode diode and an adjacent fixed array of closely packed radiation detectors to produce images of rapidly moving body organs such as the beating heart. A variety of alternative X-ray source embodiments are also disclosed.

Abstract: A radiation imaging system employs a superheated, superconducting colloid detector subjected to an external magnetic field so that the colloid grains are maintained in a metastable superconducting state in the absence of radiation. Intersecting sets of select wires are imbedded in the detector that divide the detector into volumetric resolution elements. Grains in each resolution element that absorb photons emanating from an object "flip" to the normal conducting state. By applying coincident currents to the select wires defining each element, a local magnetic field is produced that opposes the external field so that all the "flipped" grains are reset to the superconducting state. This produces a flux change proportional to the number of photons incident on that element which is sensed and used to develop an x-ray image of the object.

Abstract: A radiation imaging system employs a super-heated, super-conducting colloid detector subjected to an external magnetic field such that all the colloid grains are maintained in the metastable super-conducting state in the absence of radiation. Imbedded in the detector are intersecting helical sensing coils that divide the detector into volumetric resolution elements. The grains in each element that absorb x-ray or gamma ray photons emanating from an object make a transition to the normal conducting state thereby producing flux changes in the vicinities of the grains which induce signals in the coils defining the resolution element in which those grains are located. The number of signals from each element are accumulated separately and used to produce an image of the object.