Abstract: The present invention concerns an X-ray examination apparatus allowing to produce images of an object through the scanning of the object by at least two fan-shaped beams having different energy spectra, and obtained from a single X-ray source, thereby allowing to obtain simultaneously images of the object adapted to contain different informations.
Type:
Grant
Filed:
September 29, 1986
Date of Patent:
March 15, 1988
Assignee:
Thomson-CGR
Inventors:
Andre Plessis, Emile Gabbay, Jacques Trotel
Abstract: A collimator blade assembly for a computed tomographic X-ray scanner comprising a blade of X-ray beam stopping material having an aperture for passing X-rays and an X-ray penetrable member closing at least a portion of that aperture to reinforce the material and thereby minimize collimator blade/detector clearances while preventing undesirable collimator blade vibration.
Abstract: A device for positioning a flattening filter in the center of an x-ray radiation, which comprises a drive means for driving the flattening filter between positions outside and inside the x-ray radiation; and a stop means for restricting the inside movement of the drive means to the center position of the flattening filter.
Abstract: A method of testing dose calibrator linearity comprising the steps of serially interposing a plurality of shields between the sample and detector, each shield having a given thickness to absorb a desired fraction of the radiation; measuring the activity of the sample as attenuated by the shields; calculating the actual activity of the sample at each level of attenuation; and comparing the measured activities with the calculated activities. For carrying out the method several embodiments of shields are described.
Abstract: The present invention relates to a device for measuring the effective dose. In a preferred embodiment, the device includes a detector located in a cavity accommodated in the periphery of an inner cylinder which is eccentrically mounted in a right cylinder. The diameter of the right cylinder is close to twice the diameter of the eccentric cylinder and the cylinders are driven in rotation to set a rectilinear displacement to the cavity. The device can be used to determine the variation of the absorbed dose rate versus depth.
Type:
Grant
Filed:
October 19, 1982
Date of Patent:
August 27, 1985
Assignees:
Commissariat a l'Energie Atomique, Merlin Gerin
Abstract: A device for linearly oscillating one or more of a plurality of X-ray filter elements singly or in combination in and out of an X-ray beam at television frame rates. First and second substantially coplanar filter elements are adjacent each other and formed as a unitary member that is transverse to the X-ray beam. It is slidable bidirectionally on parallel guide tracks in one plane. A servo motor drives a closed loop belt which attaches to said member. A third planar filter element runs on tracks in a plane parallel to that of the unitary member. There are lug means on the third element spaced apart in the direction of its travel member that project up and are between the lug means on the third element to enable pushing or pulling it. Thus, the first and second filter elements can be oscillated alternately in and out of the X-ray beam by moving said unitary member without engaging the third element so it stays out of the beam.
Abstract: A radiation detector adapted to be used with a computerized tomographic apparatus, wherein filters prepared from a radiation-absorbing material are provided on the outside of a radiation-permeable window in the positions facing radiation-detecting cells. The filters compensate for differences between the radiation-detecting properties of the detection cells, thereby equalizing said radiation-detecting properties.
Abstract: In an exemplary embodiment, two radiation detectors are arranged behind the radiography subject. One of the detectors is covered by a radiation filter. A different radiation attenuation along the radiation paths of the respective detectors thereby takes place, so that, through division of the output signals of the detectors, a quotient signal can be obtained which corresponds to the radiation transparency of the radiography subject.
Abstract: The exemplary embodiments produce successive x-ray beams with different wavelengths and may comprise a rotating anode whose anode body has x-ray generating parts of different materials. Heretofore, the x-rays arising at the parts have been conducted through filters outside the tube which, synchronously moved, are allocated to the parts of the rotating anode. Since, however, the allocation of the filters to the parts of the anode is difficult in such a subsequent synchronization, according to the disclosure a fixed allocation ensues in that the filters are incorporated into the tube and are integrated in the rotation of the anode. To that end, they are designed as walls lying at right angles in the discharge path of the x-rays and are rigidly connected to the shaft of the anode arrangement. Such x-ray tubes are particularly suitable as a radiation source for employment in medical x-ray diagnostics.
Abstract: 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.
Type:
Grant
Filed:
February 27, 1981
Date of Patent:
August 16, 1983
Assignee:
General Electric Company
Inventors:
Robert B. Hauck, Floyd L. Gray, Richard T. Brandt
Abstract: An apparatus utilizing filter-fluorescer combinations is provided to measure short bursts of high fluence x-rays above 120 keV energy, where there are no practical absorption edges available for conventional filter-fluorescer techniques. The absorption edge of the prefilter is chosen to be less than that of the fluorescer, i.e., E.sub.PRF <E.sub.F, contrary to the prior art technique E.sub.PRF >E.sub.F. In this way, the response function is virtually zero between E.sub.PRF and E.sub.F and well defined and enhanced in an energy band of less than 1000 keV above the 120 keV energy.
Type:
Grant
Filed:
July 7, 1981
Date of Patent:
July 12, 1983
Assignee:
The United States of America as represented by the United States Department of Energy
Abstract: A method and apparatus for measuring the content of an element by means of X-ray-radiation. Electrons from the cathode of a low-power X-ray tube are directed onto one side of the anode of said tube, said anode comprising a thin layer of anode material on a beryllium plate. The electrons excite primary X-ray-radiation in the anode material, including the characteristic X-ray lines. The radiation passes out through the opposite side of the anode as transmission radiation and is directed onto the element to be measured, whereupon fluorescense occurs, said fluorescense being caused by the characteristic lines. The fluorescense lines of the substance are then isolated by means of a balanced filter.