X-ray CT apparatus

1. An X-ray CT apparatus comprising:

a reference image acquisition unit that acquires a reference image by irradiating a subject placed on a bed with X-rays,

a movable region calculating unit that calculates a transversely movable region of the bed on the basis of height of the bed and size of the subject, and/or calculates an up and down movable region of the bed on the basis of position of the bed for the transverse direction and size of the subject,

a movement destination setting unit that sets a movement destination of the bed within the transversely movable region and/or the up and down movable region calculated by the movable region calculating unit,

a filter size setting unit that sets size of a filter for adjusting radiation intensity of the X-rays,

an imageable region calculating unit that calculates an imageable region on the basis of the movement destination of the bed set by the movement destination setting unit and the filter size set by the filter size setting unit, and

a displaying unit that displays the imageable region calculated by the imageable region calculating unit superimposed on the reference image.

2. The X-ray CT apparatus according to claim 1 , wherein the displaying unit further displays the transversely movable region and/or the up and down movable region calculated by the movable region calculating unit superimposed on the reference image.

3. The X-ray CT apparatus according to claim 1 , wherein the X-ray CT apparatus further comprises a tilt angle setting unit that sets a gantry tilt angle, and

the movable region calculating unit calculates the transversely movable region and/or the up and down movable region further on the basis of the tilt angle set by the tilt angle setting unit.

4. The X-ray CT apparatus according to claim 1 , wherein when the transverse movement destination and/or the up and down movement destination of the bed displayed on the displaying unit is moved by a user, the movement destination setting unit calculates distance of movement of the bed on the basis of the moved transverse movement destination and/or up and down movement destination of the bed, and sets a movement destination of the bed.

5. The X-ray CT apparatus according to claim 1 , wherein when the reference image displayed on the displaying unit is moved by a user, the movement destination setting unit calculates distance of movement of the bed on the basis of position of the moved reference image, and sets a movement destination of the bed.

6. The X-ray CT apparatus according to claim 5 , wherein when the reference image displayed on the displaying unit is moved, the displaying unit identifiably displays a region not obtained at the time of imaging for obtaining the reference image.

7. The X-ray CT apparatus according to claim 1 , wherein when imaging is performed for a plurality of sites, the movement destination setting unit sets a single movement destination of the bed for the plurality of sites on the basis of FOVs or movement destinations set for every site through an input device.

8. The X-ray CT apparatus according to claim 7 , wherein the X-ray CT apparatus comprises a cumulative dose calculating unit that calculates cumulative dose for every site, and

the displaying unit displays a site suffering large cumulative dose as a cumulative dose warning region.

9. An X-ray CT apparatus comprising a gantry that has an opening and can be tilted with respect to the vertical direction, and a bed that can move in the opening of the gantry, which is provided with:

a reference image acquisition unit that collects a reference image by irradiating a subject placed on the bed with X-rays,

a movable region calculating unit that calculates a movable region of the bed on the basis of positional information of the bed, tilt angle of the gantry, and size of the subject,

a movement destination setting unit that sets a movement destination of the bed in the movable region calculated by the movable region calculating unit, and

a displaying unit that displays the movable region of the bed and/or the movement destination of the bed set by the movement destination setting unit together with the reference image.

10. The X-ray CT apparatus according to claim 9 , wherein:

the movable region calculating unit calculates a transversely movable region of the bed on the basis of the positional information of the bed for a direction of a height of the bed.

11. The X-ray CT apparatus according to claim 9 , wherein:

the movable region calculating unit calculates an up and down movable region of the bed on the basis of the positional information of the bed for a horizontal direction perpendicular to a direction of a height of the bed.

12. The X-ray CT apparatus according to claim 9 , wherein:

the X-ray CT apparatus further comprises a filter size setting unit that sets size of a filter for adjusting radiation intensity of the X-rays, and

an imageable region calculating unit that calculates an imageable region on the basis of the movement destination of the bed set by the movement destination setting unit and the filter size set by the filter size setting unit, and

the displaying unit displays the imageable region calculated by the imageable region calculating unit superimposed on the reference image.

13. The X-ray CT apparatus according to claim 9 , wherein:

the displaying unit is provided with a GUI that receives setting of the movement destination of the bed and/or setting of FOV from a user.