Tomographic apparatus for producing transverse layer images
First Claim
1. A tomographic apparatus for producing transversal layer images of a subject, consisting of an x-ray measuring arrangement with a transmitting arrangement for emitting x-rays and with radiation receivers which determine the intensity of radiation behind the subject by scanning the x-rays, and of a drive system for the measuring arrangement with a rotating frame for producing rotational movements of the x-ray measuring arrangement, the transmitting arrangement comprising a plurality of x-ray tubes with their focuses lying substantially on a common circle, and arranged offset at predetermined angles relative to one another, one ray receiver being provided for each x-ray tube, the x-ray tubes being fixedly mounted on the rotating frame and having pinhole diaphragms for condensing the x-ray beam in such a way that it impinges on the ray receivers, said diaphragms being mounted for movement parallel to a tangent of the circle of rotation of the x-ray tubes and the radiation receivers being mounted for movement parallel to the path of the diaphragm such that the x-ray beam always strikes the ray receivers during movement thereof in the scanning of the subject, the ray receivers each consisting of a row of detectors movable as a group parallel to a tangent of the circle of rotation of the x-ray tubes, all of the detectors of each row being simultaneously impinged by the respective x-ray beam in each position of the respective diaphragm during each cycle of tangential movement of the diaphragms, and the rows of detectors all moving tangentially synchronously with the movement of the respective pinhole diaphragms during each cycle of tangential movement of the diaphragms, whereby all the detectors of all of the rows are used substantially simultaneously while the rows of detectors each cover only a fraction of the length of the tangential path along which the respective x-ray beam is moved during each cycle of tangential movement of the respective diaphragm.
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Abstract
In an illustrated embodiment a plurality of x-ray sources are arranged at equal angles about a rotating frame. Each source and detector arrangement may provide the desired number of measurements such as 240, so that the required angular movement for scanning is reduced by a factor corresponding to the number of sources. In one embodiment with three sources and 240 detectors for each source, the desired number of measured values may be obtained by rotation through 120 degrees instead of 360 degrees. In another illustrative embodiment, the narrow beam from the x-ray source covers about 30 detectors, the beam and detectors being linearly scanned so as to generate about 240 measurements, there being three source-detector arrangements separated by 60 degrees, so that scanning is carried out by rotation through 60 degrees rather than 180 degrees.
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Citations
2 Claims
- 1. A tomographic apparatus for producing transversal layer images of a subject, consisting of an x-ray measuring arrangement with a transmitting arrangement for emitting x-rays and with radiation receivers which determine the intensity of radiation behind the subject by scanning the x-rays, and of a drive system for the measuring arrangement with a rotating frame for producing rotational movements of the x-ray measuring arrangement, the transmitting arrangement comprising a plurality of x-ray tubes with their focuses lying substantially on a common circle, and arranged offset at predetermined angles relative to one another, one ray receiver being provided for each x-ray tube, the x-ray tubes being fixedly mounted on the rotating frame and having pinhole diaphragms for condensing the x-ray beam in such a way that it impinges on the ray receivers, said diaphragms being mounted for movement parallel to a tangent of the circle of rotation of the x-ray tubes and the radiation receivers being mounted for movement parallel to the path of the diaphragm such that the x-ray beam always strikes the ray receivers during movement thereof in the scanning of the subject, the ray receivers each consisting of a row of detectors movable as a group parallel to a tangent of the circle of rotation of the x-ray tubes, all of the detectors of each row being simultaneously impinged by the respective x-ray beam in each position of the respective diaphragm during each cycle of tangential movement of the diaphragms, and the rows of detectors all moving tangentially synchronously with the movement of the respective pinhole diaphragms during each cycle of tangential movement of the diaphragms, whereby all the detectors of all of the rows are used substantially simultaneously while the rows of detectors each cover only a fraction of the length of the tangential path along which the respective x-ray beam is moved during each cycle of tangential movement of the respective diaphragm.
Specification
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- Resources
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Current AssigneeSiemens AG
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Original AssigneeSiemens AG
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InventorsFranke, Kurt
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Primary Examiner(s)Church, Craig E.
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Application NumberUS05/779,671Time in Patent Office757 DaysField of Search250/445 T, 250/523, 250/505US Class Current378/9CPC Class CodesA61B 6/032 Transmission computed tomog...A61B 6/06 DiaphragmsA61B 6/4014 arranged in multiple source...
