General Electric Company

Richard T Brandt

Robert B Hauck

Gregory D Schwehr

Floyd L Gray

James J Kandler

Paul William Hein

An X-ray table having an elevator mounted on a base for vertical movement, an intermediate support mounted on the elevator for moving longitudinally, and a carriage with a patient cradle on it for moving longitudinally on the support. A pair of gas springs mounted at the forward end of the table provides a constant upward force to compensate for weight of the elevator and the cantilevered load which is exerted as the patient cradle is extended in the longitudinal direction. There are individual servomotors for driving the support and the cradle. The intermediate support drive includes a drive bar and switch assemblies for sensing any force of more than 25 lbs., for example, exerted on the patient or patient cradle and for disengaging the servodrives in response thereto. The cradle drive incorporates a zero-backlash longitudinal friction drive which includes a harmonic drive unit to achieve accurate positioning of the patient. An encoder is driven by a closed-loop cable attached to the patient cradle to accurately indicate its position and speed even though there is a two-stage drive.

Patient-positioning X-ray table

Curved X-ray filter elements are arranged circularly around a drum. Alternate circumferentially adjacent elements have different filtration properties. Diametrically opposite elements have the same properties. An X-ray source provides a sequence of alternate low and high energy X-ray beam pulses. A multicell X-ray detector produces X-ray attenuation data for each pulse and the data is switched to alternate memories. A drum drive motor is energized at power line frequency. A pinion on the motor shaft turns a gear. A lug that is mounted for angular adjustment on the gear drives the drum. A multiple blade shutter is also mounted on the gear for angular adjustment and rotation with the gear. The shutter alternately interrupts and restores a light beam to a photosensitive device which produces corresponding signal state changes or trigger signals. The signals are used to synchronize the low and high energy X-ray pulses, the filter element angular locations and memory switching with power line frequency.

Spinning filter for X-ray apparatus

A cable retractor for a computed tomography scanner that is driven with a motor and a belt through two revolutions between clockwise and counterclockwise limits about a horizontal axis. An inner drum is fixed on the scanner for rotation therewith and a stationary outer drum is concentric to the inner drum. Cables are fastened where they enter the outer drum and exit the inner drum on their way to the scanner. A loop is formed in the cable in the circular channel defined by the concentric drums to provide enough cable length for the scanner to make two revolutions. A disk facing the channel is journalled for rotation on the inner drum. Pulleys extend axially from the disk to support the cable loop. The disk is belt driven so its angular motion is a constant fraction of the motion of the scanner whereby the pulleys move at the same rate as the loop to keep it supported as cable is reeled between the drums. Solenoid operated latching levers assure stopping the scanner rotation before the cables would be overstressed.

Computed tomography system cable retractor

A collimator assembly for defining an aperture for the passage of a diagnostic x-ray beam in an x-ray diagnostic apparatus which may, for example, be used in computer assisted tomography. The collimator assembly comprises a framework adapted to be secured to the x-ray apparatus contiguous the x-ray tube, and includes a first and a second blade subassembly lying in a common plane with each other in the path of x-rays emanating from the x-ray tube. Leaf spring means connect each of the blade subassemblies to the framework, the leaf spring means biasing the first and second blade subassemblies into abutting relation to each other whereby to define a zero aperture condition for the passage of a diagnostic x-ray beam through said collimator assembly to the patient. Cam follower means are carried by each of the respective first and second blade subassemblies, and movable cam means are mounted on the framework and engageable with the cam follower means of said first and said second blade subassemblies whereby movement of the cam means is effective to move the first and second blade subassemblies against the biasing force of the spring means to a controlled degree of opening between the first and second blade subassemblies whereby to define a collimating aperture of a predetermined size between said subassemblies for the passage of a diagnostic x-ray beam of a predetermined size to the patient. A further feature of the collimator assembly is the use of a direct acting sensing arrangement for sensing the collimating opening between the two blade subassemblies. This sensing arrangement is embodied in an electromagnetic transducer in the form of a linear variable differential transformer.

Collimator for x-ray diagnostic apparatus

An x-ray source and a detector array are mounted on opposite sides of a generally horizontally extending longitudinal axis of a rotating base. The rotating base is journaled on a tiltable frame. The frame is supported on curved tracks for tilting by translating along a curved path about a fixed transverse virtual axis of rotation which is perpendicular to and intersects the rotational axis of the rotating base. Tilting the frame permits making an x-ray scan through a layer of a patient which is at an acute angle relative to the longitudinal axis. The azimuth drive for the rotatable frame utilizes a toothed belt. A self-acting friction brake is provided for constraining the rocking base. A hoist is provided for making installation and removal of the x-ray source convenient.

Gantry for computed tomography

An X-ray source and a detector array are mounted on opposite sides of a generally horizontally extending longitudinal axis of a rotating base. The rotating base is journaled on a tiltable frame. The frame is supported on curved tracks for tilting by translating along a curved path about a fixed transverse virtual axis of rotation which is perpendicular to and intersects the rotational axis of the rotating base. Tilting the frame permits making an X-ray scan through a layer of a patient which is at an acute angle relative to the longitudinal axis. The azimuth drive for the rotatable frame utilizes a toothed belt. A self-acting friction brake is provided for constraining the rocking base. A hoist is provided for making installation and removal of the X-ray source convenient.

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New Berlin, WI, United States of America

Richard T Brandt