X-ray computer tomography apparatus
View Patent ↗An X-ray absorptance map associated with an object to be examined is generated on the basis of scanogram data obtained from a predetermined direction of the object, and imaging conditions are determined on the basis of the absorptance map. Before tomography, an index representing a radiation dose in the execution of scan in accordance with the imaging conditions is calculated and displayed, together with the imaging conditions. Every time the imaging conditions are changed, an index representing a radiation dose is calculated and displayed. Tomography is executed in accordance with the finally determined imaging conditions. This makes it possible to reduce the radiation dose to the object and obtain a tomographic image with high quality.
1. An X-ray computer tomography apparatus comprising:
an X-ray source which emits X-rays;
an X-ray detector which has a plurality of detection elements configured to detect X-rays transmitted through an object to be examined;
a scanogram generating section which generates a scanogram of the object on the basis of an output from said X-ray detector;
a distribution information generating section which generates distribution information of X-ray absorptances or absorbed X-ray doses in a first direction by dividing the scanogram in matrixes and calculating X-ray absorptances or absorbed X-ray doses on a matrix basis, and in a second direction different from the first direction by adding X-ray absorptances or absorbed X-ray doses on a matrix basis in the second direction;
an imaging condition determining section configured to determine the imaging condition on the basis of the distribution information in the first and second directions; and
a controller which controls computer tomography of the object on the basis of the imaging condition.
2. The apparatus according to claim 1 , further comprising:
an X-ray amount calculating section which calculates a radiation dose to the object or a total amount of X-rays emitted from said X-ray source on the basis of the imaging condition; and
a display device which displays the calculated radiation dose or the total X-ray amount.
3. An X-ray computer tomography apparatus comprising:
an X-ray source configured to emit X-rays;
an X-ray detector which has a plurality of detection elements configured to detect X-rays transmitted through an object to be examined;
a scanogram generating section configured to generate a scanogram of the object on the basis of an output from said X-ray detector;
a distribution information generating section configured to generate distribution information of X-ray absorptances or absorbed X-ray doses in a first direction of the object by dividing the scanogram into matrixes;
an imaging condition determining section configured to determine an imaging condition on the basis of the distribution information and determine a size of the matrix in accordance with an imaging slice thickness or imaging slice width; and
a controller configured to controls computer tomography of the object on the basis of the imaging condition.
4. The apparatus according to claim 3 , further comprising:
an X-ray amount calculating section which calculates a radiation dose to the object or a total amount of X-rays emitted from said X-ray source on the basis of the imaging condition; and
a display device which displays the calculated radiation dose or the total X-ray amount.
5. An X-ray computer tomography apparatus comprising:
an X-ray source configured to emit X-rays;
an X-ray detector which has a plurality of detection elements configured to detect X-rays transmitted through an object to be examined;
a scanogram generating section configured to generate a scanogram of the object on the basis of an output from said X-ray detector;
a distribution information generating section configured to generate distribution information of X-ray absorptances or absorbed X-ray doses in a first direction of the object by dividing the scanogram into matrixes;
an imaging condition determining section configured to determine an current value supplied to said X-ray source on the basis of the distribution information; and
a controller configured to control computer tomography of the object such as to change the current value supplied to said X-ray source in accordance with movement of said X-ray source on the basis of the imaging condition.
6. The apparatus according to claim 5 , further comprising:
an X-ray amount calculating section which calculates a radiation dose to the object or a total amount of X-rays emitted from said X-ray source on the basis of the imaging condition; and
a display device which displays the calculated radiation dose or the total X-ray amount.
7. An X-ray computer tomography apparatus comprising:
an X-ray source configured to emit X-rays;
an X-ray detector which has a plurality of detection elements configured to detect X-rays transmitted through an object to be examined;
a scanogram generating section configured to generate a scanogram of the object on the basis of an output from said X-ray detector;
an imaging condition determining section configured to determine an imaging condition associated with computer tomography of the object on the basis of a scanogram in a first direction of the object, the imaging condition including a current value of said X-ray source which is varied in accordance with a position of said X-ray source in a body axis direction and a rotation angle centered on the body axis of the object, in such a manner that each standard deviation of computer tomography to be acquired is made uniform;
an X-ray amount calculating section configured to calculate a radiation dose to the object or a total amount of X-rays emitted from said X-ray source on the basis of the imaging condition; and
a display device configured to display the calculated radiation dose or the total X-ray amount.