X-ray CT apparatus

1. An X-ray CT apparatus for obtaining an internal image of a test subject by using X-rays;

the X-ray CT apparatus comprising:

X-ray generation means for generating X-rays irradiated on the test subject;

X-ray detection means for detecting X-rays that have passed through the test subject;

rotary drive means for simultaneously rotating the X-ray generation means and the X-ray detection means about a center line of rotation;

a first casing for enclosing the X-ray generation means and the X-ray detection means;

a test-subject table on which the test subject is placed;

a first table transporting mechanism for transporting the test-subject table between a first table position and a second table position, the first table position being a position where the main portion of the test-subject table receives the X-rays generated by the X-ray generation means, and the second table position being a position where the main portion of the test-subject table is on the outside of the first casing;

a second table transporting mechanism for transporting the test-subject table closer to or farther from the center line of rotation of the X-ray generation means and the X-ray detection means;

means whereby the test-subject table on which the test subject is placed is transported from the second table position to the first table position by the first table transporting mechanism; and

means whereby the distance of the test subject from the center line of rotation of the X-ray generation means and the X-ray detection means is varied by the second table transporting mechanism in accordance with the size of the test subject.

2. The X-ray CT apparatus according to claim 1 , further comprising:

a second casing for enclosing the second table position; and

the second casing having a pair of doors that move open or closed in order to open up or close off a path on which the test-subject table is transported by the first table transporting mechanism.

3. The X-ray CT apparatus according to claim 2 , wherein a window for observing the interior is provided to at least one of the pair of doors.

4. The X-ray CT apparatus according to claim 1 , further comprising:

laser pointer means for indicating a position by laser light;

a window provided to the first casing or the second casing in order to observe the position indicated by the laser pointer means;

input means for inputting data; wherein

the means for varying the distance of the test subject varies the distance of the test subject from the center line of rotation of the X-ray generation means and the X-ray detection means by the second table transporting mechanism in accordance with the data input from the input means.

5. The X-ray CT apparatus according to claim 1 , further comprising:

input means for inputting data;

means whereby the distance of the test subject in relation to the center line of rotation of the X-ray generation means and the X-ray detection means is determined by X-ray fluoroscopy; wherein

the means for varying the distance of the test subject varies the distance of the test subject from the center line of rotation of the X-ray generation means and the X-ray detection means by the second table transporting mechanism in accordance with the data determined by X-ray fluoroscopy.

6. The X-ray CT apparatus according to claim 1 , further comprising a third table transporting mechanism for transporting the test-subject table to a third table position, which is a position even farther from the first casing than the second table position.

7. The X-ray CT apparatus according to claim 1 , wherein the test-subject table has a curved cross-sectional shape in which the surface for receiving the test subject is recessed.