General Electric Company

Joseph J Grass

Gary F Relihan

David M Barrett

Robert J Dobberstein

Randolph N Wendt

Emanuel V Polizzi

Jerry L Neitzell

Marvin P Glyzewski

An X-ray tube is movable between a minimum distance from an image receptor and a maximum distance. Signals are generated representative of the X-ray tube focal spot-to-image distance (SID), the peak kilovoltage (kVp) that is to be applied to the X-ray tube anode during a fluorographic exposure and the desired brightness of the X-ray image. The signals are processed in a manner that results in a control signal being developed that adjusts the X-ray tube filament current in a way that produces an X-ray tube current (mA) during the exposure which results in a constant limited X-ray dose rate at the X-ray beam entrance plane of a patient at any permissible kVp and SID setting and assures that the dose rate limit will not be exceeded at minimum permissible SID regardless of the selected kVp.

Automatic X-ray entrance dose compensation

The isocenters of two independent frontal and lateral viewing X-ray systems are made coincident using an X-ray permeable target frame that has congruent crosshairs defined by X-ray impermeable lines on opposite side walls. A small steel ball is located in the frame between side walls on a line running from the intersection of one set of crosshairs to the other. A television display of the X-ray image of the ball resting on the patient supporting table top with the frame leveled and of the crosshairs with the frontal system having the central ray of its X-ray beam vertical and then horizontal and with X-ray impermeable crosshairs on the image receptor permits shifting the frame until the crosshairs on it and on the receptor are coincident with the ball and the isocenter in vertical and horizontal orientations. The procedure for establishing the isocenter of the lateral system is comparable. The target frame is also mounted for rotating relative to protractors to measure and calibrate the angular orientations of the systems.

Device for aligning cooperating X-ray systems

Collimator for regulating the shape and size of the pattern of radiation projected on a radiation detector from a radiation source, particularly for regulating the beam of radiation in a medical diagnostic x-ray machine. One or more (preferably three) longitudinally stacked plates are provided, the top plate having a large aperture, the middle plate having a medium sized aperture, and the lower plate having a small aperture. The middle and lower plates are provided with means to substantially open up their apertures, rendering these plates inactive when they are not in use. Each plate is longitudinally movable between first and second extremities of travel, the first extremity being nearest the radiation source. When each plate is at its first extremity of travel the beam of radiation has its maximum size. The size is first reduced by advancing the first plate longitudinally to its second extremity of travel, then by placing the second in its active position in the beam and advancing it to its second extremity of travel, and finally by placing the third plate in its active position in the beam and advancing the third plate to its second extremity of travel. A drive means and associated structure is also disclosed for placing the plates in their active positions and advancing the three plates. The present invention allows continuous variation of the size of the x-ray beam projected on the detector over a wide range, while at the same time providing a collimator which is longitudinally compact. The collimator can be provided with apertures of any shape, allowing projection of an irregularly shaped pattern which is continuously variable in size.

Collimator with adjustable aperture

A device for handling a group of cables running to medical x-ray equipment that is movable in all degrees of freedom comprises: A vertical axle mounted overhead; a boom swingable in a horizontal plane on the axle; a housing on the axle having openings for receiving and clamping the ends of respective flexible cable enclosing tubes, one of which extends over the boom to the equipment and the other of which establishes a cable path continuing to a swivel mechanism that is spaced from the axle and mounted overhead.

Cable handling device for diagnostic x-ray apparatus

A device for aligning the central ray of an x-ray beam with the center of an image receptor comprises a metal tube in a mounting which is provided with means for establishing the axis of the tube perpendicular to the plane of the image receptor or other plane which is perpendicular to the central ray. The tube is mounted in such manner that the region around it is x-ray permeable. The mounting is adapted for being moved in parallelism with the plane such that alignment of the central ray with a point on the receptor may be determined when the circular shadow cast by the outside of the tube is concentric with the circular image of the tube bore.

Growing community of inventors

Brookfield, WI, United States of America

Joseph J Grass