X-ray computed tomography apparatus

1. An X-ray computed tomography apparatus, comprising:

a first X-ray tube configured to generate X-rays with which a subject to be examined is irradiated;

a first X-ray detector configured to detect X-rays transmitted through the subject;

a second X-ray tube which generates X-rays with which a treatment target of the subject is irradiated;

a rotating mechanism which rotates said first X-ray tube, said first X-ray detector, and said second X-ray tube around the subject;

a reconstructing unit configured to reconstruct an image based on data detected by said first X-ray detector; and

a support mechanism configured to support said second X-ray tube such that a central axis of X-rays from said second X-ray tube tilts with respect to a body axis of the subject,

wherein said support mechanism supports said second X-ray tube to allow said second X-ray tube to freely move along the body axis of the subject.

2. An apparatus according to claim 1 , further comprising:

a first X-ray collimator having an aperture which is used to collimate X-rays from said first X-ray tube and has an aperture width that is variable within a first range; and

a second X-ray collimator which is used to collimate X-rays from said second X-ray tube and has an aperture width that is variable within a second range wider than the first range.

3. An apparatus according to claim 1 , further comprising:

a high voltage generator configured to selectively supply power to said first X-ray tube within a first range and to selectively supply power to said second X-ray tube within a second range wider than the first range.

4. An apparatus according to claim 1 , further comprising:

a second X-ray detector corresponding to said second X-ray tube.

5. An X-ray computed tomography apparatus, comprising:

a first X-ray tube configured to generate X-rays with which a subject to be examined is irradiated;

a first X-ray detector configured to detect X-rays transmitted through the subject;

a second X-ray tube configured to generate X-rays with which a treatment target of the subject is irradiated;

a second X-ray collimator having an aperture which is used to collimate X-rays from said second X-ray tube and whose aperture width and position are variable;

a rotating mechanism configured to rotate said first X-ray tube, said first X-ray detector, and said second X-ray tube around the subject;

a reconstructing unit configured to repeat reconstruction of an image based on data detected by said X-ray detector along with rotation of said first X-ray tube and said first X-ray detector;

an image processor configured to repeatedly extract a region of the treatment target from the image;

a controller configured to dynamically change the aperture of said collimator upon rotation of said second X-ray tube based on the extracted region of the treatment target; and

a first X-ray collimator having an aperture which is used to collimate X-rays from said first X-ray tube and has an aperture width that is variable, the aperture of said first X-ray collimator having a variable range narrower than a variable range of the aperture of said second X-ray collimator.

6. An apparatus according to claim 5 , wherein said second X-ray tube is arranged with respect to said first X-ray tube such that said first X-ray tube rotates ahead of said second X-ray tube.

7. An apparatus according to claim 5 , wherein said controller is configured to dynamically change at least one of a center position and a width of the aperture of said collimator.

8. An apparatus according to claim 5 , wherein the aperture of said first X-ray collimator is set such that X-rays from said first X-ray tube cover an entire slice of the subject, and the aperture of said second X-ray collimator is set to be smaller than the aperture of said first X-ray collimator such that a treatment target of the subject is substantially exclusively irradiated with X-rays from said second X-ray tube.

9. An apparatus according to claim 5 , further comprising:

a second X-ray detector corresponding to said second X-ray tube.

10. An X-ray computed tomography apparatus, comprising:

a first X-ray tube configured to generate X-rays with which a subject to be examined is irradiated;

a first X-ray detector configured to detect X-rays transmitted through the subject;

a second X-ray tube configured to generate X-rays with which the subject is irradiated; and

a high voltage generator configured to supply power to said first X-ray tube within a first range and to supply power to said second X-ray tube within a second range wider than the first range, wherein

said high voltage generator includes a plurality of power supplies, a first selector configured to select one of connections between said first X-ray tube and said plurality of power supplies, and a second selector configured to select one of connections between said second X-ray tube and said plurality of power supplies, and

said apparatus further comprises a controller configured to control said first and second selectors to supply, to said second X-ray tube, power higher than that supplied to said first X-ray tube.

11. An apparatus according to claim 10 , further comprising:

a second X-ray detector corresponding to said second X-ray tube.

12. An X-ray computed tomography apparatus, comprising:

a first X-ray tube configured to generate X-rays with which a subject to be examined is irradiated;

a first X-ray detector configured to detect X-rays transmitted through the subject;

a second X-ray tube configured to generate X-rays with which the subject is irradiated;

a high voltage generator configured to supply power to said first X-ray tube within a first range and to supply power to said second X-ray tube within a second range wider than the first range;

a first X-ray collimator having an aperture which is used to collimate X-rays from said first X-ray tube and has an aperture width that is variable; and

a second X-ray collimator having an aperture which is used to collimate X-rays from said second X-ray tube and has an aperture width that is variable, the aperture of said second X-ray collimator having a variable range wider than a variable range of the aperture of said first X-ray collimator.

13. An apparatus according to claim 12 , wherein the aperture of said first X-ray collimator is set such that X-rays from said first X-ray tube cover an entire slice of the subject, and the aperture of said second X-ray collimator is set to be smaller than the aperture of said first X-ray collimator such that a treatment target of the subject is substantially exclusively irradiated with X-rays from said second X-ray tube.

14. An X-ray computed tomography apparatus, comprising:

a first X-ray tube configured to generate X-rays with which a subject to be examined is irradiated;

a first X-ray detector configured to detect X-rays transmitted through the subject;

a second X-ray tube configured to generate X-rays with which the subject is irradiated;

a first X-ray collimator having an aperture which is used to collimate X-rays from said first X-ray tube and has an aperture width that is variable within a first range; and

a second X-ray collimator having an aperture which is used to collimate X-rays from said second X-ray tube and has an aperture width that is variable within a second range wider than the first range.

15. An apparatus according to claim 14 , wherein a minimum width of the aperture of said second X-ray collimator is smaller than a minimum width of the aperture of said first X-ray collimator.

16. An apparatus according to claim 14 , wherein a maximum width of the aperture of said second X-ray collimator is substantially equal to a maximum width of the aperture of said first X-ray collimator.

17. An apparatus according to claim 14 , further comprising:

a second X-ray detector corresponding to said second X-ray tube.