Imatron, Inc.

Leland Stanford Junior University

Ge Medical Systems Global Technology Company, LLC

Other

University of California

Douglas P Boyd

Roy E Rand

Giovanni Lanzara

Kristian R Peschmann

Jonathan Harman

Peter Michael Edic

Susan Candell

Robert A Sparks

Geordie Henry Zapalac

Brian K Rutt

Michael Goitein

William B Herrmannsfeldt

James R Quinn

A scanning electron beam computed tomographic system eliminates axial offset between target and detector by disposing the target, collimator, and detector such that active portions of the target and detector are always diametrically opposite each other. This result is achieved by providing a helical target, collimator, and detector, or by providing planar target, collimator, and detector components that are inclined relative to the vertical axis such that active portions of the target and detector are always diametrically opposite each other. Either configuration eliminates cone beam error and the necessity to correct for same. Further, the system can provide multi-slice scanning of an object that is in constant motion at a critical velocity, without having to interpolate data. Conventional helical scanning may still be undertaken. Detector elements can be disposed axially to improve signal/noise ratio and to produce a cone beam cancellation effect.

Electron beam computed tomographic scanner system with helical or tilted target, collimator and detector components to eliminate cone beam error and to scan continuously moving objects

Certain embodiments of the present invention provide a method for three-dimensional cine EBA/CTA imaging. The method includes monitoring a cardiac cycle of a patient and selecting a trigger point along the cardiac cycle. When the cardiac cycle of the patient reaches the trigger point, a computed tomography (CT) scan of the patient is initiated. At least two CT scans of the patient are performed during a time period over two or more cardiac cycles. A cine angiography image is constructed from the at least two CT scans.

Method for three dimensional cine EBA/CTA imaging

A method for facilitating a reduction in motion artifacts includes comparing two sequential scanned images to determine motion.

Methods and apparatus for motion compensation in image reconstruction

Electron beam computed tomographic scanner system with helical or tilted target, collimator, and detector components to eliminate cone beam error and to scan continuously moving objects

A scanned volume computerized tomography scanner in which an electron beam is scanned along a target to generate successive cones of x-rays. A vane collimator receives said x-rays and from successive adjacent fan becomes for irradiating a volume of an object. A detector array receives the x-ray fan becomes and generates signals representative of the transmitted x-ray amplitude across the fan beams. The object and x-ray source are rotated relative to one another to collect data for reconstructing an image of the scanned volume.

Scanned volume CT scanner

A scanning electron beam CT system generates an electron beam along a beam source axis offset from the scanner axis, or axis of symmetry, thereby permitting the X-ray subject to pass completely through the stationary gantry. The electron beam is produced with the first drift tube region of an evacuated housing chamber, and is directed downstream toward a second region that includes a gantry. A scan target and a tuning target, each concentric with and defining a plane normal to the system axis of symmetry, are located in the gantry. A beam optics system, through which the electron beam passes, is located within the housing intermediate the electron gun and gantry. A control system focusses and scans the electron beam upon the scan target, maintaining a beam spot of desired quality. Upon impingement by the scanning beam spot, the scan target emits a fan beam of X-rays. A detector array, concentric with and defining a plane normal to the system axis of symmetry, is located opposite the scan target within the gantry and provides output signals that are computer processed to reconstruct a CT image of a subject placed within the gantry. The scanner axis is preferably above the beam source axis, and preferably the drift tube is straight, defining a drift tube axis that is inclined relative to the scanner axis, or is parallel to the scanner axis but not co-axial therewith. Alternatively, the drift tube may be kinked.

Off-axis scanning electron beam computed tomography system

A rotating x-ray tube includes an electron-beam accelerator assembly having an indirectly heated cathode structure. The cathode structure includes an electron-emitting region mounted at the center of a rotationally symmetric Pierce-cathode configuration. An electron beam travels along a selected path as the tube rotates so that the electron beam strikes selected portions of a target mounted within the tube as it rotates. Two magnetic coils and a ferromagnetic mirror plate are arranged to function as a single quadrupole electromagnet, which has its axis parallel to and offset from the electron beam and which elongates the electron beam in a radial direction.

High duty-cycle x-ray tube

A scanner assembly having a C-shaped gantry rotatably supported by a support head. An x-ray source and a detector assembly are mounted on said gantry for independent movement with respect to one another along said gantry.

Computerized tomographic x-ray scanner system and gantry assembly

X-ray tube includes a rotatable envelope in which is mounted an electron gun at one end and a target anode at the other end. A fixed means for deflecting the electron beam from the electron gun is provided to deflect the electron beam on a fixed path as the envelope of the x-ray tube rotates about an axis. The electron beam being confined to a fixed path results in the electron beam striking various positions of the target anode to provide for improved heat dissipation. The electron beam is deflected along the fixed path using magnetic deflection means including magnetic deflection coils positioned external of the envelope to provide a deflection field transverse to the electron beam. The target anode is cooled by directing a cooling fluid on an external side of the target anode.

Rotating X-ray tube with external bearings

A compact computerized tomographic x-ray scanner having a patient tunnel in which the walls and the ends of the patient tunnel include shielding material to form a shielded enclosure in which the patient body portion is scanned.

Self shielded computerized tomographic scanner

A tomogram is obtained by tomosynthesis in a high speed CT scanning system in which fan beams of radiation are generated by sweeping an electron beam along a target, and collimated X-rays emitted by the target are received by an array of detectors after passing through a patient area between the target and array of detectors. The patient is moved through the collimated x-rays as the measurments are obtained, and the measurements are time-correlated to correspond to data measurements for a plurality of projection radiographs. The measurements for the plurality of radiographs are combined to tomosynthesize a tomogram at a selected plane in the patient.

Tomosynthesis using high speed CT scanning system

A high speed multiple section, computed-tomographic x-ray scanner is provided. The scanner utilizes a multiple-anode, scanning electron beam x-ray source to provide high speed scanning of sections of the body. No mechanical motion is involved.

X-Ray transmission scanning system and method and electron beam X-ray

A fan-shaped beam or a fan array of individual beamlets of penetrating radiation, such as X-ray or .gamma.-ray radiation, is directed through a planar slice of the body to be analyzed to a position sensitive detector. The fan beam and the detector are caused to move in a rectilinear or nearly rectilinear fashion so that the individual beamlets or rays of penetrating radiation scan across the body and each detector records a parallel ray shadowgraph at a different angle of rotation (scan angle) with respect to the body and covering a range of scan angles less than 180.degree. and typically approximately 90.degree.. The recorded shadowgraphic data is then reconstructed into a 3-D tomograph of the body using a method of successive approximations. The resultant scanner may be used to analyze planes of the body parallel to the major axis thereof such as saggital or coronal as well as transaxial planes. In a preferred embodiment, the position sensitive detector includes detector elements arranged for detecting penetrating radiation passing through the body in a number of divergent planes diverging from the source. 3-D tomographs are reconstructed from the corresponding divergent plane shadowgraphic data. An advantage in use of the scanner of the present invention is that faster scan times are achieved due to the rectilinear or nearly rectilinear translation of the scanner which enables a reduction of blurring of the resultant tomographs due to biological motion. A further advantage is that multiple planes may be scanned simultaneously.

Limited scan angle fan beam computerized tomography

A fan-shaped beam of penetrating radiation, such as X-ray or .gamma.-ray radiation, is directed through a slice of the body to be analyzed to a position sensitive detector for deriving a shadowgraph of transmission or absorption of the penetrating radiation by the body. A number of shadowgraphs are obtained for different angles of rotation of the fan-shaped beam relative to the center of the slice being analyzed. The detected fan beam shadowgraph data is reordered into shadowgraph data corresponding to sets of parallel paths of radiation through the body. The reordered parallel path shadowgraph data is then convoluted in accordance with a 3-D reconstruction method by convolution in a computer to derive a 3-D reconstructed tomograph of the body under analysis. In a preferred embodiment, the position sensitive detector comprises a multiwire detector wherein the wires are arrayed parallel to the direction of the divergent penetrating rays to be detected. A focussed grid collimator is interposed between the body and the position sensitive detector for collimating the penetrating rays to be detected. The source of penetrating radiation is preferably a monochromatic source.

Fan beam X- or .gamma.-ray 3-D tomography

A fan-shaped beam of penetrating radiation, such as X-ray or .gamma.-ray radiation, is directed through a slice of the body to be analyzed to a position sensitive detector for deriving a shadowgraph of transmission or absorption of the penetrating radiation by the body. A number of such shadowgraphs are obtained for different angles of rotation of the fan-shaped beam relative to the center of the slice being analyzed. The detected fan beam shadowgraph data is reordered into shadowgraph data corresponding to sets of parallel paths of radiation through the body. the reordered parallel path shadowgraph data is then convoluted in accordance with a 3-D reconstruction method by convolution in a computer to derive a 3-D reconstructed tomograph of the body under analysis. In a preferred embodiment, the position sensitive detector comprises a multiwire detector wherein the wires are arrayed parallel to the direction of the divergent penetrating rays to be detected. A focussed grid collimator is interposed between the body and the position sensitive detector for collimating the penetrating rays to be detected. The source of penetrating radiation is preferably a monochromatic source.

Growing community of inventors

Woodside, CA, United States of America

Douglas P Boyd