JPH0311773B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an improvement in a multi-orbit X-ray tomography apparatus.

In conventional multi-orbit X-ray tomography equipment, in order to move the X-ray tube on many types of orbits, such as straight lines, circles, and spirals, the rotary motion mechanism 1 and linear motion are used, as shown in principle in Fig. 1. The X-ray tube 3 is connected to the mechanism 2 to move the X-ray tube 3. Therefore, since two types of motion with different types are combined, the mechanism becomes complicated, and the length of the linear motion mechanism 2 is
Since the linear movement distance of the radiation tube 3 must be slightly longer than the distance corresponding to the desired tomography angle, an increase in the size of the apparatus is unavoidable.

In view of the above, it is an object of the present invention to provide a multi-orbit X-ray tomography apparatus that has a simple mechanism and is compact by creating a known trajectory using only rotational motion.

Hereinafter, one embodiment of the present invention will be described with reference to the drawings from FIG. 2 onwards. FIG. 2 is a partially sectional front view, and FIG. 3 is a schematic plan view seen from above in FIG. In these figures, a rotating disk 22 is rotatably held on a substrate 21 by a bearing or the like, and a rotating shaft 23 is rotatably held by the rotating disk 22 by a bearing or the like. A rotary wheel 25 is rotatably attached to a shaft 24 located at the center of the rotary disk 22 by means of a bearing or the like. The rotating disk 22 is driven to rotate by a belt/pulley mechanism, chain/sprocket mechanism, etc. by a drive unit 27, and the rotating shaft 23 is driven by a belt/pulley mechanism, chain/sprocket mechanism, etc. via a rotating wheel 25. Rotational force is transmitted from the drive section 27. An arm 26 is attached to this rotating shaft 23. The tip of this arm 26 is rotatably connected to a holding frame 41 that holds the X-ray tube 3. The holding frame 41 holds the X-ray tube 3 rotatably in the direction shown by the arrow, and is further connected to the interlocking rod 42 so as to be rotatable in the direction shown by the arrow. This interlocking rod 42 is held in a guide tube 43 so as to be slidable in its length direction and does not rotate.When the holding frame 41 is moved by the arm 26, it swings about the guide tube 43 as a fulcrum. By holding frame 4
1 is moved in parallel from the state shown in FIG. A photographing means such as a film (not shown) is connected to the other end of the interlocking rod 42, and when the X-ray tube 3 moves together with the holding frame 41, this photographing means moves in a direction opposite to that of the X-ray tube 3. They are beginning to move relatively. The links 44 and 45 constitute a parallelogram link together with the holding frame 41 and the interlocking rod 42, and no matter how the X-ray tube 3 moves, the X-ray tube 3 and the collimator 4 are always connected.
and directs the camera towards the photographing means. Note that the configuration and operation after the holding frame 41 is moved along various trajectories by the arm 26 are the same as those of a normal multi-orbit X-ray tomography apparatus, so further explanation will be omitted.

As shown in FIG. 4, the drive unit 27 includes motors 28 and 29 that rotate independently, gearboxes 30 and 31 connected to these motors by a chain sprocket mechanism, etc.
Clutch device 32 connected between the input shafts of 31
By the action of this clutch device 32, the rotating disc 22 and rotating shaft 23 can be rotated completely independently of each other or in conjunction with each other.

Next, the operation will be explained. First, when moving on a straight trajectory, as shown in Figure 5, the rotating disk 2
The distance between the center c of 2 and the center b of the rotating shaft 23, and b
The distance from the point to the point of action a at the tip of the arm 26 is made equal, and the diameter of the sprocket of the rotary wheel 25 is twice that of the sprocket of the rotary shaft 23. Then, the motor 29 is stopped so that the rotating wheel 25 remains stationary and does not rotate, and the motor 28 is rotated to rotate only the rotating disk 22. Then, as shown in FIG. 5A, the point of action a initially coincides with the point c, but as the rotating disk 22 rotates, the center b of the rotating shaft 23 rotates around the point c as shown by the arrow. As the rotating shaft 23 rotates, the arm 26 rotates, and the point of application a moves linearly, passing through the state shown in FIG. 5B and reaching the state shown in FIG. 5C. In this case, when the arm 26 is fully extended, the point of application a reaches the end of the linear trajectory, and when it is contracted (FIG. 5A), the length may be 1/4 of the length of the linear trajectory. Therefore, compared to the conventional linear motion mechanism 2 shown in Fig. 1, which has a length equal to the length of the linear trajectory, the guide length can be reduced to 1/4, making the device more compact. can be achieved.

In the case of a circular orbit, as shown in Figure 6, first
The rotary wheel 25 is fixed in the state shown in Figure A, the rotating disk 22 is rotated to bring it into the state shown in Figure 6B, and the radius of the circular orbit is set by determining the distance from point c to point of action a, and then If the rotating disk 22 and the rotating wheel 25 are rotated at the same number of rotations (same angular velocity), the point of action a will draw a circular orbit as shown by the dotted line.

The case of a spiral trajectory is as follows. In the above description of the circular orbit, if the rotary wheel 25 is fixed and the rotary disk 22 is rotated, the distance (radius) between a and c will change, and if the rotary disk 22 and the rotary wheel 25 are rotated at the same number of rotations. He said that it will draw a circular orbit. Therefore, by utilizing the relationship between the two, the rotating wheel 25 is rotated at a constant rotation speed (point a, that is, the desired rotation speed of the X-ray tube 3), and the rotating disk 22 is rotated by the rotating wheel 25 at a slightly higher rotation speed (this is If the point a is rotated at a speed determined by the characteristics of the spiral orbit, the point a will draw a spiral orbit whose radius gradually increases as shown by the dotted line in FIG. Note that the rotation speed of the rotating disc 22 is
If the number of rotations is lower than , it is possible to draw a spiral trajectory in which the radius of rotation gradually decreases.

As described above with respect to the embodiments, according to the present invention, the construction is made such that many types of trajectories are drawn by combining rotational motions, so that the construction can be made simple and compact. Moreover, since a straight trajectory can be obtained with only a small rotational movement, it is possible to shorten the imaging time.

[Brief explanation of the drawing]

Fig. 1 is a conceptual diagram of a conventional example, Fig. 2 is a front view partially sectionally showing an embodiment of the present invention, Fig. 3 is a schematic plan view seen from above Fig. 2, and Fig. 4. is the second
A side view of the drive unit 27 shown in the figure, seen from the right side in FIG.
Figures 5A, B, and C are schematic diagrams for explaining linear orbits, Figures 6A and B are schematic diagrams for explaining circular orbits, and Figure 7 is a schematic diagram for explaining spiral orbits. be. 3...X-ray tube, 4...collimator, 21...
Substrate, 22... Rotating disk, 23... Rotating shaft, 25
... Rotating wheel, 26 ... Arm, 27 ... Drive unit,
28, 29...Motor, 30, 31...Gearbox, 32...Clutch device, 41...Holding frame, 42...Interlocking rod.

Claims (1)

[Claims] 1. The X-ray tube and the photographing means are placed opposite to each other with the subject in between, and the X-ray tube and the photographing means are moved in various orbits while interlocking the two so that they move relative to each other in opposite directions. Multi-orbital X that moves
In a line tomography apparatus, a rotary disk rotatably held on a substrate, a rotary shaft rotatably attached to a location other than the center of rotation of the rotary disk, and the rotary disk and the rotary shaft are each rotationally driven. two rotary drives, a clutch device connected between the two rotary drives for interrelating both rotary drives, and an arm attached to the rotary shaft; A multi-orbital X-ray tomography apparatus characterized in that the motion is applied to the X-ray tube.