US 6,289,074 B1 · X-ray computed tomography method and system

Abstract

An X-ray computed tomography (CT) method of producing sectional images and panoramic images while reducing the exposure dose and time. The method includes producing an X-ray projection image on a two-demensional X-ray image sensor by turning a rotary arm within a scope of angle according to the projection conditions, while locally radiating conical X-ray beams, with a small width in the rotating direction of the beams, with the rotating center of the rotary arm fixed at the center position of the region to be X-rayed and the X-ray projection images are processed using specific equation as previously prepared by a computer to extract image information, and thereby to produce a sectional image of the local region of the object to be examined.

Claims24

Dependent claims

An X-ray computed tomography method of the local region of the object in which X-rays are radiated locally on part of the object, by turning a rotary arm with an X-ray generator and a two-dimensional image sensor faced to each other, the method comprising:

producing an X-ray projection image of a local region on the two-dimensional X-ray image sensor by turning the rotary arm within a scope of angle according to projection conditions, while locally radiating conical X-ray beams from the X-ray generator covering only the local region of the object, with a rotating center of the rotary arm fixed at a center position of the local region, the local region being a part of the object to be examined, and
arithmetically processing the X-ray projection image thus produced and extracting a three-dimensional X-ray absorption coefficient distribution information on the local region and thereby producing a sectional image of the local region of the object to be examined.

An X-ray computed tomography method in which X-rays are radiated locally on part of an object by turning a rotary arm with an X-ray generator and a two-dimensional image sensor faced to each other, the method comprising:

successively producing X-ray projection images of a dental arch on the two-dimensional X-ray image sensor by radiating a conical X-ray beam covering only a virtual local region from the X-ray generator while turning the rotary arm within a scope of angle according to projection conditions with a rotating center of the rotary arm fixed at a center position of such a virtual local region as containing an orbit of the conical X-ray beam required to obtain a panoramic image of the dental arch, or part of the object, and
taking out only partial X-ray projection images produced by the conical X-ray beam out of the X-ray projection images of the dental arch successively formed on the two-dimensional image sensor and then arithmetically processing the X-ray projection images thus picked out so as to extract a three-dimensional X-ray absorption coefficient distribution information on the dental arch as image information and thereby producing a panoramic image of the dental arch.

An X-ray computed tomography system comprising:

an X-raying means having a rotary arm with an X-ray generator and a two-dimensional X-ray image sensor faced to each other,
an X-ray beam width restriction means for restricting a width of a conical X-ray beam radiated from the X-ray generator at least in a scanning direction,
a rotary arm drive control means for rotating the rotary arm with a rotation center of the rotary arm fixed during projection, the means being so designed to move and preset at least one of a rotation center of the rotary arm and an object to be X-rayed before projection, and
an image processing unit for arithmetically processing an X-ray projection data and extracting a three-dimensional absorption coefficient distribution information of the object through which the X-ray is passed as image information,
wherein the rotary arm is turned in order to form an X-ray projection image of the two-dimensional image sensor within a scope of angle according to projecting conditions, while controlling a beam width of the conical X-ray beam from the X-ray generator which contain a local region of the object, or a part of the object and widens in X-ray scanning direction and the X-ray projection image thus formed is arithmetically processed to produce a sectional image of the local region of the object.

2 more elements

An X-ray computed tomography system comprising:

an X-raying means having a rotary arm with an X-ray generator and a two-dimensional X-ray image sensor faced to each other,
an X-ray beam width restriction means for restricting a width of a conical X-ray beam radiated from the X-ray generator at least in a scanning direction,
a rotary arm drive control means for rotating the rotary arm, and
an image processing unit for arithmetically processing an X-ray projection data and extracting a three-dimensional absorption coefficient distribution information of an object through which the X-ray is passed as image information,
wherein the conical X-ray beam containing only a virtual local region is radiated from the X-ray generator so as to successively form an X-ray projection image of a dental arch on the two-dimensional sensor, while turning the rotary arm within a scope of angle according to pojecting conditions, with a center of the rotary arm fixed at a center of the virtual local region containing an orbit of the conical X-ray beam required to obtain a panoramic image of the dental arch, or a part of the object, and only partial X-ray projection image of the dental arch formed by radiation of the conical X-ray beam is taken out of the X-ray projection image of the dental arch successively formed on the two-dimensional sensor and then the partial X-ray projection image of the dental arch is arithmetically processed so as to extract the three-dimensional absorption coefficient distribution information of the dental arch as image information and thereby producing a panorama image of the dental arch.

2 more elements

Dependencies are inferred from the claim text.

X-ray computed tomography method and system

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X-ray computed tomography method and system

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Abstract

Claims24