EP0464645A1
Expired / Lapsed
EP
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Computed tomography scanner apparatus
Assignee: Toshiba Corp
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Filing: 1991-06-26
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Granted: —
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Expires: 2011-06-26
Abstract
Abstract 5 n7 In an X-ray CT apparatus of a helical scanning scheme, a scannogram is obtained before acquiring projection data, and a range for which a tomographic image is desired, i.e., start and end positions of a helical scanning are designated on the scannogram. Helical scanning is started, not from a position of an object corresponding to the designated start position, but from a position preceding to the designated start position by a shift distance of the top plate corresponding to one cycle of helical scanning. Helical scanning is performed until a position over the designated end position by a shift distance of the top plate corresponding to one cycle of helical scanning. The projection data is acquired and is stored in correspondence with the scanning position. When reconstruction is to be performed, first, a desired slice position is designated on the scannogram. Projection data corresponding to a range preceding to the slice position by the shift distance of one cycle of helical scanning and a range succeeding to the slice position by the shift distance of one cycle are selected from the acquired data. Reconstruction is performed based on the selected projection data.
Inventors
- 👤 Tetsurou Hada
Bibliographic Details
Application Number
—
Jurisdiction
EP
Data Source
google_patents
Last Synchronized
2026-11-09 09:29
CPC Classifications
A; A61; A61B; A61B6/00; A61B6/02; A61B6/03; A61B6/032; A61B6/027; A61B6/04; A61B6/0487
Claims Analysis
Total Claims: 19
Claim 1
Independent Claim
110 words
A computed tomography scanner apparatus characterized by comprising: first means (18) for obtaining tomographic image data of an object by helically scanning the object with a radiation ray; second means (16) for obtaining one-directional projection image data of the object by radiating a radiation ray onto the object; means (26) for designating a desired slice on the one-directional projection image data obtained by said second means; and third means (24) for selecting, from tomographic image data obtained by said first means, data corresponding to a predetermined range including the desired slice designated by said designating means and obtaining a tomographic image of the designated slice from the data thus selected.
Claim 2
Dependent Claim
110 words
A computed tomography scanner apparatus characterized by comprising: first means (18) for obtaining tomographic image data of an object by helically scanning the object with a radiation ray; second means (16) for obtaining one-directional projection image data of the object by radiating a radiation ray onto the object; means (26) for designating a desired slice on the one-directional projection image data obtained by said second means; and third means (24) for selecting, from tomographic image data obtained by said first means, data corresponding to a predetermined range including the desired slice designated by said designating means and obtaining a tomographic image of the designated slice from the data thus selected.
Claim 3
Dependent Claim
47 words
An apparatus according to claim 1, characterized in that said third means selects first tomographic image data for projection angles required for reconstructing the tomographic image and second tomographic image data for interpolating the tomographic image data for the projection angles required for reconstructing the tomographic image.
Claim 4
Dependent Claim
31 words
An apparatus according to claim 1, characterized in that said third means selects tomographic image data corresponding to two cycles of helical scanning with the designated slice position as the center.
Claim 5
Dependent Claim
124 words
A computed tomography scanner apparatus characterized by comprising: first means (18) for obtaining tomographic image data of an object by helically scanning the object with a radiation ray; second means (16) for obtaining one-directional projection image data of the object by radiating a radiation ray onto the object; means (26) for designating a desired range on the projection image data obtained by said second means; and third means (24) for limiting a portion of the object helically scanned by said first means so as to obtain tomographic image data corresponding to a range as a sum of the desired range designated by said designating means, a first predetermined range preceding to the desired range, and a second predetermined range succeeding to the desired range.
Claim 6
Dependent Claim
124 words
A computed tomography scanner apparatus characterized by comprising: first means (18) for obtaining tomographic image data of an object by helically scanning the object with a radiation ray; second means (16) for obtaining one-directional projection image data of the object by radiating a radiation ray onto the object; means (26) for designating a desired range on the projection image data obtained by said second means; and third means (24) for limiting a portion of the object helically scanned by said first means so as to obtain tomographic image data corresponding to a range as a sum of the desired range designated by said designating means, a first predetermined range preceding to the desired range, and a second predetermined range succeeding to the desired range.
Claim 7
Dependent Claim
24 words
An apparatus according to claim 4, characterized in that each of said first and second predetermined ranges corresponds to one cycle of helical scanning.
Claim 8
Dependent Claim
70 words
A computed tomography scanner apparatus characterized by comprising: means (16) for obtaining a scannogram of an object by radiating a radiation ray onto the object; means (26) for designating an arbitrary position on the scannogram; and helical scanning means (18) for obtaining a tomographic image by helically scanning, with a radiation ray, a portion of the object corresponding to a predetermined range including the position designated by said designating means.
Claim 9
Dependent Claim
70 words
A computed tomography scanner apparatus characterized by comprising: means (16) for obtaining a scannogram of an object by radiating a radiation ray onto the object; means (26) for designating an arbitrary position on the scannogram; and helical scanning means (18) for obtaining a tomographic image by helically scanning, with a radiation ray, a portion of the object corresponding to a predetermined range including the position designated by said designating means.
Claim 10
Dependent Claim
30 words
An apparatus according to claim 6, characterized in that said helical scanning means scans a range corresponding to two cycles of helical scanning with the designated position as the center.
Claim 11
Dependent Claim
51 words
An apparatus according to claim 7, characterized in that said helical scanning means obtains, by interpolation, projection data for predetermined projection angles of the designated position from projection data of the same projection angle preceding and succeeding to the designated position, and thereafter reconstructs the tomographic image of the designated position.
Claim 12
Dependent Claim
166 words
A computed tomography scanner apparatus characterized by comprising: means (16) for obtaining a scannogram of an object by radiating a radiation ray onto an object; first designating means (26) for designating an arbitrary range on the scannogram; helical scanning means (12, 14) for obtaining projection data by helically scanning a portion of the object, with a radiation ray, the portion corresponding to a range as a sum of the range designated by said designating means, a first predetermined range preceding to the desired range, and a second predetermined range succeeding to the desired range; means (18) for storing projection data obtained by said helical scanning means; second designating means (26) for designating an arbitrary position on the scannogram; and means (20) for obtaining a tomographic image by reading out, from said storing means, projection data corresponding to a third predetermined range preceding to the position designated by said second designating means and a fourth predetermined range succeeding to the position designated by said second designating means.
Claim 13
Dependent Claim
166 words
A computed tomography scanner apparatus characterized by comprising: means (16) for obtaining a scannogram of an object by radiating a radiation ray onto an object; first designating means (26) for designating an arbitrary range on the scannogram; helical scanning means (12, 14) for obtaining projection data by helically scanning a portion of the object, with a radiation ray, the portion corresponding to a range as a sum of the range designated by said designating means, a first predetermined range preceding to the desired range, and a second predetermined range succeeding to the desired range; means (18) for storing projection data obtained by said helical scanning means; second designating means (26) for designating an arbitrary position on the scannogram; and means (20) for obtaining a tomographic image by reading out, from said storing means, projection data corresponding to a third predetermined range preceding to the position designated by said second designating means and a fourth predetermined range succeeding to the position designated by said second designating means.
Claim 14
Dependent Claim
25 words
An apparatus according to claim 9, characterized in that said first, second, third, and fourth predetermined ranges each corresponds to one cycle of helical scanning.
Claim 15
Dependent Claim
105 words
A computed tomography scanner apparatus characterized by comprising: helical scanning means (18) for obtaining projection data by helically scanning an object with a radiation ray, and storing the projection data in correspondence with the position of the object along a scanning direction; means (16) for obtaining a scannogram by radiating a radiation ray onto the object; means (26) for designating an arbitrary position on the scannogram; and means (20) for reading out, from said helical scanning means, projection data corresponding to a predetermined portion including the position designated by said designating means and reconstructing a tomographic image of the position designated by said designating means.
Claim 16
Dependent Claim
105 words
A computed tomography scanner apparatus characterized by comprising: helical scanning means (18) for obtaining projection data by helically scanning an object with a radiation ray, and storing the projection data in correspondence with the position of the object along a scanning direction; means (16) for obtaining a scannogram by radiating a radiation ray onto the object; means (26) for designating an arbitrary position on the scannogram; and means (20) for reading out, from said helical scanning means, projection data corresponding to a predetermined portion including the position designated by said designating means and reconstructing a tomographic image of the position designated by said designating means.
Claim 17
Dependent Claim
38 words
An apparatus according to claim 11, characterized in that said reconstructing means reads out projection data of a range corresponding to two cycles of helical scanning with the designated position as the center from said helical scanning means.
Claim 18
Dependent Claim
43 words
An apparatus according to claim 12, characterized in that said reconstructing means reconstructs the tomographic image after interpolating projection data of the projection angle of the designated position from projection data preceding and succeeding to the designated position of the same projection angle.
Claim 19
Dependent Claim
33 words
An apparatus according to claim 13, characterized in that said designating means designates a reconstruction range by designating two positions, and said reconstructing means performs reconstruction at predetermined intervals within the designated range.
References Cited (Backward Citations)
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