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EP0383232A2 Expired / Lapsed EP ⏱️ 0.0 years remaining

Computerized tomographic apparatus

Assignee: Toshiba Corp
•
Filing: 1990-02-12
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Granted: —
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Expires: 2010-02-12
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Abstract

Abstract A patient platform (11) of a gantry assembly (9) is inserted into a scanning space (3) of a housing dome (1). Within the dome (1) around the space (3) is pro­vided an array (5) of X-ray detectors arranged circumferentially. An X-ray tube (7) is rotatably dis­posed outside the array (5). When the object (P) on the patient platform (11) is inserted into the space (3), the X-ray tube (7) irradiates X-rays in a fan shape toward the object (P). The X-ray detector array (5) performs a nutation movement during the rotation of the X-ray tube (7) so that one of the X-ray detectors on the X-ray irradiation path which is closer to the X-ray tube (7) is outside the X-ray irradiation path. In this way, the object (P) is continuously scanned in a helical man­ner with X-rays. The output of the detector array (5) is supplied to an interpolation circuit (13). The interpolation circuit (13) performs a pre-process on the output of the X-ray detector array, thereby providing projection data. The interpolation circuit (13) inter­polates a projection data at a predetermined slice (22) and having a given projection angle (φ) in accordance with two projection data at two slices located on both sides of the predetermined slice and having the given projection angle and a distances between the two slices and the predetermined slice.

Inventors

  • 👤 Masahiro Intellectual Property Division Ozaki
  • 👤 Toshihiro Intellectual Property Division Rifu

Bibliographic Details

Application Number —
Jurisdiction EP
Data Source google_patents
Last Synchronized 2026-10-23 09:35
CPC Classifications
A; A61; A61B; A61B6/00; A61B6/02; A61B6/03; A61B6/032; A61B6/027; G; G06; G06T; G06T12/00; G06T12/10

Claims Analysis

Total Claims: 7
Claim 1
Independent Claim 97 words
A computerized tomographic apparatus comprising: scanning means for moving an object in one direc­tion and for rotating radiation rays within a plane intersecting a moving direction of said object to per­form helical scan on said object, thereby to provide projection data, characterized by further comprising: interpolation means (13) for interpolating a pro­jection data of a predetermined slice and having a given projection angle in accordance with two projection data of two slices located on both sides of the predetermined slice and having the given projection angle and a dis­tances between the two slices and the predetermined slice.
Claim 2
Dependent Claim 97 words
A computerized tomographic apparatus comprising: scanning means for moving an object in one direc­tion and for rotating radiation rays within a plane intersecting a moving direction of said object to per­form helical scan on said object, thereby to provide projection data, characterized by further comprising: interpolation means (13) for interpolating a pro­jection data of a predetermined slice and having a given projection angle in accordance with two projection data of two slices located on both sides of the predetermined slice and having the given projection angle and a dis­tances between the two slices and the predetermined slice.
Claim 3
Dependent Claim 142 words
An apparatus according to claim 1, character­ized in that said interpolation means (13) interpolates the projection data P C (φ, ϑ) of the predetermined slice and having a projection angle φ in accordance with the two projection data P A (φ, ϑ) and P B (φ, ϑ) of the two slices and having the projection angle φ as follows, P C (φ, ϑ) = α·P A (φ, ϑ) + (1 -α)·P B (φ, ϑ) where α is an interpolation ratio and is expressed as follows, α = (X C - X B ) / (X A - X B ) where X A - X B and X C - X B are a distance between the two slices and a distance between the predetermined slice and one of the two slices which corresponds to the projection data P B (φ, ϑ).
Claim 4
Dependent Claim 167 words
An apparatus according to claim 1, character­ized in that said interpolation means (13) comprises: means for calculating projection data P′ B (φ, ϑ) of a first slice and having a projection angle φ from counter beams; and means for interpolating the projection data P C (φ, ϑ) of the predetermined slice and having the projection angle φ in accordance with a projection data P A (φ, ϑ) of a second slice and having the projection angle φ and the projection data P′ B (φ, ϑ) of the first slice as follows, P C (φ, ϑ) = α′·P A (φ, ϑ) + (1 - α′)·P′ B (φ, ϑ) where α′ is an interpolation ratio and is expressed as follows, α′ = (X C - X′ B ) / (X A - X′ B ) where X A - X′ B and X C - X′ B are a distance between the first slice and the second slice and a distance between the predetermined slice and the first slice.
Claim 5
Dependent Claim 34 words
An apparatus according to claim 1, character­ized by further comprising: image reconstruction means (15) for processing an output of said interpolation means; and means (19) for displaying an output of said image reconstruction means.
Claim 6
Independent Claim 115 words
A method for providing a slice image of an object, comprising the steps of: moving said object in one direction while rotating radiation rays within a plane intersecting a moving direction of said object, to perform helical scan on said object, thereby providing helical scan data; designating a desired slice of said object; reconstructing an image of the desired slice based on the projection data, characterized by further com­prising the step of: interpolating a projection data at the desired slice and having a given projection angle in accordance with two helical scan data at two slices located on both sides of the desired slice and a distance between said two slices and the desired slice.
Claim 7
Independent Claim 115 words
A method for providing a slice image of an object, comprising the steps of: moving said object in one direction while rotating radiation rays within a plane intersecting a moving direction of said object, to perform helical scan on said object, thereby providing helical scan data; designating a desired slice of said object; reconstructing an image of the desired slice based on the projection data, characterized by further com­prising the step of: interpolating a projection data at the desired slice and having a given projection angle in accordance with two helical scan data at two slices located on both sides of the desired slice and a distance between said two slices and the desired slice.

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