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US 5,949,811 AGranted
X-ray apparatus
AssigneeHitachi Medical Corporation
InventorsRika Baba, Ken Ueda, Hironori Ueki, Akira Kuba, Ken Ishikawa, Takashi Ishiguro
Life of this patent
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Abstract
An X-ray apparatus acquires an X-ray image of an object by radiating X-rays to the object and includes an X-ray radiator for radiating X-rays to an object. An imager acquires an X-ray image of the object and radiation dose controller controls the radiation dose so as to acquire an X-ray image having a predetermined X-ray relative noise level on the basis of an image level of a predetermined area in the X-ray image.
Claims36
An x-ray apparatus comprising:
- an X-ray tube for radiating X-rays;
- an X-ray collimator for regulating an X-ray exposing area of an object;
- an X-ray filter for changing energy spectrum of X-ray exposing the object and/or an X-ray grid for eliminating X-ray scattered when the X-ray transmits the object;
- X-ray detection means for acquiring an X-ray image of the object;
- display means for displaying the X-ray image;
- storage means for storing a first function showing a relation among an averaged output value of the X-ray detection means and a tube voltage of the X-ray tube and a thickness of the object, wherein the relation is preliminarily measured in a state where predetermined values are, respectively, set to mAs value of the X-ray tube, the X-ray exposing area of the object, a distance between the object and an input face of the X-ray detection means, and a gain of the X-ray detection means, with respect to combinations of the plurality of X-ray filters and/or the plurality of X-ray grids, and for storing a second function showing a ratio of change in the averaged output values of the X-ray detection means preliminarily measured by setting change amounts of the X-ray exposing area of the object and the distance from the object to the input face of the X-ray detection means for predetermined values to variables, with respect to combinations of the plurality of X-ray filters and/or the plurality of X-ray grids;
- radiographic conditions calculation means for calculating imaging conditions for radiography on the basis of imaging conditions for fluoroscopy and the first and second functions stored in the storage means;
- and
- control means for controlling the mAs value and the tube voltage of the x-ray tube and the gain of the X-ray detection means on the basis of the calculation result of the radiographic conditions calculation means.
6 more elements
An X-ray apparatus comprising:
- X-ray radiation means for radiating X-rays to an object;
- imaging means for acquiring an X-ray image of the object;
- X-ray image prediction means for forming a predicted X-ray image to be acquired next by using linear lines or two-or larger-dimensional curves on the basis of at least one X-ray image acquired just before forming the predicted X-ray image;
- radiation dose control means for controlling a radiation dose so that the X-ray image having a predetermined X-ray relative noise value can be acquired on the basis of an image level of a predetermined area in the X-ray image;
- and
- signal control means for controlling an optical iris and/or an amplification gain of the imaging means so that an analog signal before being digitized in the imaging means is equal to or less than a predetermined value on the basis of the image level of the predetermined area in the X-ray image,
- wherein the radiation dose control means calculates a ratio of a first transformed level to a second transformed level, and calculates the radiation dose from a product of the ratio and an X-ray dose in a preset standard condition, the first transformed level is obtained by transforming a minimum image level of a predetermined area in the predicted X-ray image into the preset standard condition, and the second transformed level is obtained by transforming a minimum image level of the predetermined area in the X-ray image acquired already into the preset standard condition.
4 more elements
An X-ray apparatus comprising:
- X-ray radiation means for radiating X-rays to an object;
- imaging means for acquiring an X-ray image of the object;
- X-ray image prediction means for forming a predicted X-ray image to be acquired next by using linear lines or two-or larger-dimensional curves on the basis of at least one X-ray image acquired just before forming the predicted X-ray image;
- and
- radiation dose control means for controlling a radiation dose so that the X-ray image having a predetermined X-ray relative noise value can be acquired on the basis of an image level of a predetermined area in the predicted X-ray image,
- wherein the radiation dose control means controls an X-ray pulse width on the basis of a minimum image level of the predetermined area in the predicted X-ray image.
3 more elements
An X-ray apparatus comprising:
- X-ray radiation means for radiating X-rays to an object;
- imaging means for acquiring an X-ray image of the object;
- X-ray image prediction means for forming a predicted X-ray image to be acquired next on the basis of at least one X-ray image acquired just before forming the predicted X-ray image;
- and
- radiation dose control means for controlling a radiation dose by controlling an X-ray pulse width on the basis of a minimum image level of the predetermined area in the predicted X-ray image.
2 more elements
An X-ray apparatus comprising:
- X-ray radiation means for radiating X-rays to an object;
- imaging means for acquiring an X-ray image of the object;
- X-ray image prediction means for forming a predicted X-ray image to be acquired next by using linear lines or two-or larger-dimensional curves on the basis of at least one X-ray image acquired just before forming the predicted X-ray image;
- and
- signal control means for controlling an optical iris and/or an amplification gain of the imaging means so that an analog signal before being digitized in the imaging means is equal to or less than a predetermined value on the basis of an image level of a predetermined area in the predicted X-ray image,
- wherein signal control means controls the optical iris on the basis of a maximum image level of the predetermined area in the predicted X-ray image.
3 more elements
An X-ray apparatus comprising:
- X-ray radiation means for radiating X-rays to an object;
- imaging means for acquiring an X-ray image of the object;
- X-ray image prediction means for forming a predicted X-ray image to be acquired next on the basis of at least one X-ray image acquired just before forming the predicted X-ray image;
- and
- signal control means for controlling an optical iris of the imaging means on the basis of a maximum image level of a predetermined area in the predicted X-ray image.
2 more elements
An X-ray apparatus comprising:
- X-ray radiation means for radiating X-rays to an object;
- imaging means for acquiring an X-ray image of the object;
- X-ray image prediction means for forming a predicted X-ray image to be acquired next on the basis of at least one X-ray image acquired just before forming the predicted X-ray image;
- radiation dose control means for controlling a radiation dose by controlling an X-ray pulse width on the basis of a minimum image level of a predetermined area in the predicted X-ray image;
- and
- signal control means for controlling an optical iris of the imaging means on the basis of a maximum image level of the predetermined area in the predicted X-ray image.
3 more elements
An X-ray apparatus comprising:
- X-ray radiation means for radiating X-rays to an object;
- imaging means for acquiring an X-ray image of the object;
- X-ray image prediction means for forming a predicted X-ray image to be acquired next by using linear lines or two-or larger-dimensional curves on the basis of at least one X-ray image acquired just before forming the predicted X-ray image;
- and
- radiation dose control means for controlling a radiation dose so that the X-ray image having a predetermined X-ray relative noise value can be acquired on the basis of an image level of a predetermined area in the X-ray image,
- wherein the radiation dose control means calculates a ratio of a first transformed level to a second transformed level, and calculates the radiation dose from a product of the ratio and an X-ray dose in a preset standard condition, the first transformed level is obtained by transforming a minimum image level of a predetermined area in the predicted X-ray image into the preset standard condition, and the second transformed level is obtained by transforming a minimum image level of the predetermined area in the X-ray image acquired already into the preset standard condition.
3 more elements
An X-ray apparatus comprising:
- X-ray radiation means for radiating X-rays to an object;
- imaging means for acquiring an X-ray image of the object;
- and
- radiation dose control means for controlling a radiation dose so that the X-ray image having a predetermined X-ray relative noise value can be acquired on the basis of an image level of a predetermined area in the X-ray image,
- wherein the radiation dose control means calculates a ratio of a transformed level obtained by transforming a minimum image level of the predetermined area in the X-ray image into a preset standard condition to a standard minimum level in the X-ray image obtained in the preset standard condition, and calculates the radiation dose from a product of the ratio and an X-ray dose in the preset standard condition.
2 more elements
Dependencies are inferred from the claim text.