X-ray diagnostic apparatus comprising an X-ray filter movable along an imaging axis of X-rays

1. An X-ray diagnostic apparatus comprising:

an X-ray tube configured to generate X-rays;

an X-ray detector configured to detect X-rays generated from the X-ray tube and transmitted through an object;

an X-ray filter configured to be arranged between the X-ray tube and the object and having an opening; and

an X-ray filter support unit configured to support the X-ray filter so as to make the X-ray filter movable along an imaging axis direction of the X-rays.

2. The X-ray diagnostic apparatus of claim 1 , further comprising another X-ray filter configured to be arranged at a position located between the X-ray tube and the object and shifted along the imaging axis with respect to the X-ray filter.

3. The X-ray diagnostic apparatus of claim 1 , wherein the X-ray filter support unit supports the X-ray filter so as to make the X-ray filter movable along two axes perpendicular to the imaging axis.

4. The X-ray diagnostic apparatus of claim 1 , further comprising an X-ray filter driving unit configured to rotate and move the X-ray filter about an axis parallel to the imaging axis.

5. The X-ray diagnostic apparatus of claim 1 , further comprising:

an X-ray filter driving unit configured to move the X-ray filter; and

an X-ray filter control unit configured to control the X-ray filter driving unit in accordance with a first range on a detection surface of the X-ray detector in which X-ray reception sensitivity is lower than X-ray reception sensitivity of a second range on the detection surface of the X-ray detector.

6. The X-ray diagnostic apparatus of claim 5 , wherein the X-ray filter control unit controls the X-ray filter driving unit in accordance with a change in dose distribution in the X-ray irradiation range to maintain an irradiation range corresponding to the opening in a range set in accordance with an instruction from a user.

7. The X-ray diagnostic apparatus of claim 5 , further comprising:

an image generation unit configured to generate data of an X-ray image concerning the object based on an output from the X-ray detector; and

a feature point extraction unit configured to extract a feature point from the X-ray image by threshold processing,

wherein the X-ray filter control unit controls the X-ray filter driving unit to include the extracted feature point in the irradiation range corresponding to the opening.

8. The X-ray diagnostic apparatus of claim 1 , wherein the X-ray filter includes a plurality of filter components.

9. The X-ray diagnostic apparatus of claim 8 , further comprising:

a filter component driving unit configured to move the plurality of filter components to change at least one of a position of the opening of the X-ray filter and a size of the opening; and

a filter component control unit configured to control the filter component driving unit.

10. The X-ray diagnostic apparatus of claim 9 , wherein the filter component control unit controls the filter component driving unit in accordance with a range of the X-ray detector in which X-ray reception sensitivity is low.

11. The X-ray diagnostic apparatus of claim 9 , wherein the filter component control unit controls the filter component driving unit in accordance with a change in dose distribution in the X-ray irradiation range to maintain an irradiation range corresponding to the opening in a range set in accordance with an instruction from a user.

12. The X-ray diagnostic apparatus of claim 1 , wherein the X-ray filter support unit moves according to change of an SID so as to maintain a ratio of the SID to a distance between an X-ray focal point and the X-ray filter.

13. An X-ray diagnostic apparatus comprising:

an X-ray tube configured to generate X-rays;

an X-ray detector configured to detect X-rays generated from the X-ray tube and transmitted through an object;

a plurality of types of X-ray filters configured to be arranged between the X-ray tube and the object; and

an X-ray filter support unit configured to support the plurality of types of X-ray filters so as to make the plurality of types of X-ray filters movable along an imaging axis direction of the X-rays,

wherein the plurality of types of X-ray filters include respective attenuation coefficients different from each other.

14. The X-ray diagnostic apparatus of claim 13 , further comprising a filter selection unit configured to select, from the plurality of types of X-ray filters with different attenuation coefficients, one of the plurality of types of X-ray filters which reduces a dose of X-rays reaching a range of the X-ray detector in which X-ray reception sensitivity is high to a dose lower than a predetermined dose, in accordance with examination information of the object.

15. A diagnostic method comprising the steps of:

arranging an X-ray filter between an X-ray tube and an object;

irradiating the object with X-rays using the X-ray tube;

detecting X-rays generated from the X-ray tube and transmitted through the object; and

moving the X-ray filter along an imaging axis direction of the X-rays.

16. The diagnostic method of claim 15 , wherein the moving step includes moving, according to change of an SID, the X-ray filter along the imaging axis direction of the X-rays so as to maintain a ratio of the SID to a distance between an X-ray focal point and the X-ray filter.

17. The diagnostic method of claim 15 , wherein the moving step includes moving the X-ray filter along the imaging axis direction of the X-rays so as to maintain a high-dose range of the X-rays in a first range on a detection surface of an X-ray detector, X-ray reception sensitivity of the first range being lower than X-ray reception sensitivity of a second range on the detection surface of the X-ray detector.