JPS6392338A - X-ray tube moving method of x-ray tomographic imaging apparatus - Google Patents

Abstract

(57) [Abstract] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

Detailed Description of the Invention Field of Application of Industry-I The present invention relates to an X-ray tube moving method for moving an X-ray tube on a linear trajectory in an X-ray tomography apparatus, and in particular to a method for moving an X-ray tube on a linear trajectory. The present invention relates to a method for moving an X-ray tube of an X-ray tomography apparatus, which allows the X-ray tube to be moved continuously and eliminates impact.

2. Description of the Related Art As shown in FIG. 7, a linear trajectory mechanism of a conventional X-ray tomography apparatus includes a support member 2 slidably provided along a linear guide 1, and an X-ray tube 3 attached to this support member 2. are attached, and wires 4 are attached to both sides of the supporting member 2.
, 4 are connected to each other, and the wires 4, 4 are hooked around pulleys 5.5 provided on both sides. Then, another pulley 7 fixed to the rotating shaft 6 of the above-mentioned one pulley 5
Rotational force is transmitted from a pulley]O of a drive motor 9 via a wire 8. In addition, in FIG. 7, the reference numerals 11 and 11- are the collars 1 to 1 provided on the front side of the pulleys 5, 5.

In such a state, the X-ray tube 3 records the X-ray image with the top plate 1 and 3 on which the subject 2 is placed between them, as shown in FIG. By rotating the drive motor 9 shown in FIG. 7 in a predetermined direction, the X The wire tube 3 was moved along a linear guide 1 on a linear trajectory.

Problems to be Solved by the Invention However, in such a conventional X-ray tube movement method of an X-ray tomography apparatus, as shown in FIG. The X-ray tube 3 is placed at its stopping position 3 at both ends of the radiation movement range 1 that emits X-rays to the subject 12.
It requires an acceleration movement range P starting from a and accelerating to a position 33b that reaches iso-plane line motion, and -1- the end point of the radial movement range; This requires a deceleration movement range Q up to position 3d where the motor stops. Therefore, the maximum linear movement Ml of the X-ray tube 3 of the X-ray tomography apparatus! 1illi L is L=P
+R+Q -(1), which requires a linear movement distance that is considerably longer than the radiation movement range R in which X-rays are actually emitted. For this reason, the overall size of the X-ray tomography apparatus has been increased.

Furthermore, the linear trajectory mechanism shown in FIG. 7 is one that performs linear motion in one direction, and in order to cause the X-ray tube 3 to move linearly in a reciprocating manner with such a mechanism, it is necessary to move the X-ray tube 3 from the initial stop position 3a in FIG.
The drive motor 9 is started and accelerated, passes through the radial movement range R, and then stops once when it hits the stopper 11 at the stop position 3d in the deceleration movement range Q. Next, the drive motor 9 is reversely rotated to reach the above-mentioned stop position 3d. The drive motor 9 is started and accelerated in the opposite direction, passes through the radial movement range R, decelerates in the initial acceleration movement range P, and stops the drive motor 9 again when it hits the sl'' collar 11 at the initial stop position 3a. From then on,
This action was repeated. Therefore, the X-ray tube 3 undergoes discontinuous reciprocating linear motion, and at both ends of the motion it hits the stoppers 11 and 11, respectively, and stops, generating a large impact1. The impact is transmitted through the top plate 13 to the subject 12, which may cause discomfort or anxiety to the patient.

Furthermore, the impact described in - may cause deterioration in the image quality of tomographic images.

Note that the maximum movement distance 1 shown in FIG. In order to reduce the acceleration movement range P and deceleration movement range Q at both ends, in this case, the You have to slow down suddenly. Therefore, there is a problem in that a large motor with high torque must be used as the drive motor 9.

Therefore, an object of the present invention is to provide an X-ray tube moving method for an X-ray tomography apparatus that can solve these problems.

Means for Solving the Problems The means of the present invention for solving the problems in item 1 will be explained below based on the drawings.

FIG. 1 is an explanatory diagram showing the basic concept of an X-ray tube moving method of an X-ray tomography apparatus according to the present invention. In Figure 1, X
The ray tube 3 is supported facing an X-ray image recording medium 14 such as a film, with a top plate 13 on which the subject 2 is placed sandwiched therebetween. Then, by rotating a drive motor (not shown), the X-ray tube 3 and the X-ray image recording medium 14 are relatively moved in opposite directions on a straight line centering on a predetermined region 15 within the subject 12. 1. The X-ray tube 3 is moved on a straight trajectory.

Here, in the present invention, the X-ray tube 3 is caused to make continuous reciprocating linear movement between positions 3□ and 3□ as indicated by arrows X and Y, and the X-ray tube 3 is moved to the stop position 3.゜ to arrow Y
, an acceleration movement range P up to a turning position 3□ where the drive motor starts and accelerates in the force direction and reaches a constant rotation, and a position where it decelerates in the arrow Y2 direction and stops from the turning position 3□ where the radial movement ends. The deceleration movement range Q up to 3 degrees is the rise of continuous reciprocating linear movement in the above arrow x and y directions within the radiation movement range R that radiates X-rays to the subject 12 between positions 31 and 3□. (between positions 3° and 31) and at the falling edge (between positions 32 and 3°).

In addition, in Fig. 1, from position 3° I, arrow Y
Although the present invention is shown as decelerating in the force direction and standing up, the present invention is not limited to this.
The vehicle may be decelerated in the direction of the arrow X toward the direction o and then lowered.

Function The method for moving an X-ray tube of an X-ray tomography apparatus according to the present invention
The acceleration movement range P and deceleration movement range Q of the X-ray tube 3 and 1χ of the continuous reciprocating linear movement of the X-ray tube 3 within the radiation movement range R.
Since the movement is made to occur at the falling edge, the acceleration movement range (d) and deceleration movement range Q can be absorbed within the distance of the radial movement cylinder u1, as shown in Fig. 1. can. Therefore, X-ray/r? As is clear from FIG. 1, the maximum linear movement distance L' of No. 3 is equal to the radiation movement range I which actually radiates X-rays, resulting in a short linear movement distance. In addition, the X-ray tube 3 makes continuous reciprocating linear motion as indicated by arrows X and Y, and after hitting the bath 1-flange at both ends of the reciprocating linear motion and stopping once, it starts and accelerates in the opposite direction. Therefore, during that reciprocating linear movement,
No impact is given to wire tube 3.

Embodiments Hereinafter, embodiments of the present invention will be described in detail with reference to the accompanying drawings.

FIG. 2 is a partially sectional side view showing an example of a linear track mechanism used to carry out the method for moving an X-ray tube of an X-ray tomography apparatus according to the present invention. In FIG. 2, the pillars 20 are vertically erected on a base not shown, and in addition to the one shown, another pillar 20 is erected on the front side of the paper in FIG.

A substrate 2] is horizontally disposed at the ends of these pillars 20.

- On the lower surface side of one side of the substrate 21, there is a drive motor 22 that serves as a drive source for this mechanism, and an orbit control mechanism that outputs rotational input from the drive motor 22 through two rotation shafts 23 and 24. 25 are provided.

This orbit control mechanism 25 includes a speed change mechanism (not shown) that converts the rotational speed of the drive motor 22 to an appropriate rotational speed, and a predetermined rotational speed to the rotational output from the two rotating shafts 23 and 24 (1-). It has a power transmission switching mechanism (not shown) that provides a difference. The two rotating shafts 23 and 24 protrude from the orbit control mechanism 25 in the 1-direction, and are rotatably supported by bearings 26 and 27, respectively, on one side of the base plate 21. In addition, the above orbit control mechanism 2
The output of 5 is transmitted by two rotating shafts 23 and 24 to a rotating disk 28 and a sun southeast; 39, which will be described later.

On the other side of the L substrate 21, there is a rotatable disc 28 that is rotatably mounted. Its rotating shaft fits into the boss portion 29 of the substrate 21 and is rotatably attached by a thrust bearing 30 and a tightening member 31, and has gear teeth on its outer peripheral surface. 332 is formed.] A drive gear 33 is meshed with the gear teeth 32 of the two-part rotating disk 28.
is for rotating the rotating disk 28, and the substrate 2
] A rotating shaft 35 is held by a rolling bearing 34 provided at the center of the rotary shaft 35, making it rotatable. A pulley 36 is fixed to the upper end of this rotating shaft 35, and a pulley 36 is fixed to the upper end of the first rotating shaft 23.
7 by a belt 38 or the like. Therefore, when the first rotating shaft 23 is rotated by one drive of the drive motor 22, rotational driving force is transmitted through the pulley 37, the belt 38, the pulley 36, the rotating shaft 35, and the driving gear 33. The disk 28 rotates in a predetermined direction.

A sun gear 39 is rotatably held at the center of rotation of the rotating disk 28. This sun gear 39 is
This is one of the trajectory generating mechanisms for moving the wire tube 3 on a linear trajectory -1, and the rotating shaft 4 is held by a rolling bearing 40 provided in the rotating shaft portion of the rotating disk 28 in -1-. It is said to be free. And this rotating shaft 4
A pulley 42 is fixed to one end of the bell 1, and a pulley 43 fixed to the upper end of the second rotating shaft 24 and the bell 1 to
44 etc. are connected. Therefore, when the second rotating shaft 24 is rotated by the driving of the drive motor 22, a rotational driving force is transmitted through the pulley 43, the belt 44, the pulley 42, and the rotating shaft 41-. The gear 39 rotates in a predetermined direction.

A planetary gear 45 is rotatably attached to the periphery of the rotating disk 28 other than the center of rotation.

This planetary gear 45 also constitutes a trajectory generating mechanism for moving the X-ray tube 3, which will be described later, in a straight trajectory.
The rotating shaft 46 is fitted into a hole drilled around the periphery of the slot 8 and is rotatably attached to the slab 1 by a bearing 47 and a fastening member 48. In this attached state, the gear teeth 4 formed on the outer peripheral surface of the planetary gear 45 are
9 meshes with the gear teeth of the sun gear 39, and due to the difference in rotational speed between this sun gear 39 and the rotary disc 28, it revolves around the sun gear 339 and rotates on its own axis.

A support member 50 for the X-ray tube 3, which will be described later, is fixed to the bottom surface of the planetary gear 45. This support member 50 is a member that supports the X-ray tube 3 and moves the X-ray tube 3 on a linear trajectory, and extends diagonally downward from the bottom surface of the planetary gear 45 by a predetermined length. It rotates together with the planetary gear 45.

A vertical support shaft 51 is rotatably attached to the tip of the support member 50. And this support shaft 5
lli + t + receiver 52 is fitted in the do part of 1,
A bearing 52 holds the first support link 53 in rotation and position. The X-ray tube 3 is rotatably connected to one end of the first support link 53 by a pin connection, and a second support link 55 of the same length is connected to the F side of the first support link 53. is provided parallel to the first support link 53, and one end of the second support link 55 is rotatably pin-coupled to the X-ray tube 3. The other ends of the first and second support links 53 and 55 are connected to the upper end of a connecting member 56 that is vertically provided in parallel to the support column 20, respectively, by universal pin coupling, so that they can rotate 117 times. combined. Therefore, between the first and second support links 53, 55, the X-ray tube 3, and the connecting member 56,
The X-ray tube 3 follows the movement of the supporting member 5o and always faces in the same direction as the connecting member 56, regardless of the movement of the connecting member 56.

Although not shown in FIG. 2, an imaging device holding an X-ray image recording medium 14, etc. is disposed at a position facing the X-ray tube 3, and both are connected to the connecting portion. Consolidated by month 56.

The X-ray tube 3 and the imaging device are configured to move relative to each other in opposite directions around a fulcrum shaft (1R8 in the front) provided at the intermediate portion of the connecting member 56.

In this state, when the first and second rotating shafts 23.24 are rotated by driving the drive motor 22, the rotating disk 28, the sun gear 39, and the planetary gear 45 rotate, and together with the planetary gear 45, the rotating disk 28, sun gear 39, and planetary gear 45 rotate. When the support member 50 rotates, a parallel link mechanism consisting of the first and second support links 53, 55, the X-ray tube 3, and the connecting portion 56 operates, and as a result, the X-ray tube 3 and the imaging device move in planes parallel to each other and are interlocked so as to maintain a symmetrical position with the inspection site in the subject 12 as the center, so that the X-ray tube 3 is moved along a straight trajectory -4- It can be moved with.

Next, the principle of the X-ray tube movement method in such a mechanism will be explained. In FIG. 3, the center of the rotating disk 28 and the sun gear 39 is designated as A, the center of the planetary gear 45 that revolves and rotates around this sun gear 39 is designated as B, and a support member 50 extending from the center B of this planetary gear 45 Let C be the position of the support shaft 51 at the tip. Then, the distance between the center A and the center B is set to be equal to the distance between the center B and the position C.

Here, the number of rotations (or rotational angular velocity) of the rotary disc 28 is N1, the number of rotations of the sun gear 39 is N2, and the ratio of the number of teeth between the sun gear 39 and the planetary gear 45 is R.

Then - the above planet tooth! lf4.5 rotating disk 28-1
The rotational speed N at - is N3''' I N,, N2
l R...It can be expressed as (2). That is, the rotation speed N3 of the planetary gear 45 with respect to the rotating disk 28 is the rotation speed N of the rotating disk 28, the rotation speed N2 of the sun float 339, the number of rotations of the sun gear 39 and the planet teeth 3144.5. By appropriately combining the tooth number ratio R, various settings are possible.

The planetary gear 45 rotates on its own axis in the direction indicated by the arrow at the rotational speed N3 thus given, and also revolves around the sun gear 39 in the direction of the arrow E at a rotational speed of N. And this planetary tooth! 1 (Due to the revolution and rotation of 45,
The X-ray tube 3 attached to the planetary gear 45 via the support member 50 is parallel to the arrow X+X direction shown in FIG.
Continuous reciprocating linear motion is possible.

Next, the moving operation of the X-ray tube 23 on a linear trajectory, which performs such continuous reciprocating linear movement, will be explained with reference to FIGS. 4 to 6. Here, the straight trajectory is the above-mentioned A
This can be obtained by adding the condition N5=2N to the condition B=I3C. First, in correspondence with the orbital acceleration from the midpoint of the reciprocating linear motion of the X-ray tube 3 shown in FIG. 1, the operation start state is shown in FIG.
It is assumed that position C of the support shaft 51 at the tip of the support member 50 extending from the center B of the planetary gear 45 overlaps with the center A of the sun gear 39. At this time, the position C of the support shaft 51 is located at the center between C2C shown in FIG.

In this state, when the rotating disk 28 is rotated in the direction of arrow F and the sun gear 39 is rotated in the direction of arrow G, the planetary gears 45 rotate in the direction of the arrow, and the sun gear 3
9 in the direction of arrow E. At this time, the tip C of the support member 50 moves in the direction of the arrow y1. After the start of this operation, the positions of the planetary gear 45 and the support member 50 are sequentially
- Indicated by dash-dot and dash-dotted lines. Now, when the center of the planetary gear 45 moves to B' after a certain time 1 has elapsed after the start of operation, the tip C of the support member 50 moves on the left line segment A B C shown in FIG. Located at C'.

This is because after the start of the operation, points B' and C' move while ΔAB'C' always forms an isosceles triangle with point B' as the apex. Furthermore, the rotating disk 28
When the sun gear 39 and the sun gear 39 are rotated in the same direction, the planetary gear 45 further revolves in the direction of the arrow E, its center moves on the line segment ABC and is located at the point B#, and the tip of the support member 50 Similarly, move on line segment A 13 C to point CJ
located at r.

This is the position where the tip C of the support member 50 has moved to the leftmost side, and the X-ray tube 3 attached via the support shaft 51 at the tip of the support member 50 is started and accelerated from the entrainment state to stand up. This is an operation of increasing acceleration movement range P.

Next, from this state, as shown in FIG. 5, the rotating disk 28 is further rotated in the direction of arrow F, and the sun gear 39 is
When rotated in the direction of arrow G, the planetary gear 45 rotates in the direction of arrow G and also revolves around the sun float 39 in the direction of arrow E. At this time, the tip of the support member 50 is at the point C
Turn around at '' and move in the direction of arrow X, entering radial movement.

Thereafter, as shown in FIG. 4, the planetary gear 45 and the support member 50 sequentially move along the paths indicated by the dashed-dot line and the dashed-two dotted line. During this time, △AB'C' is always at point B'
The support member 50 moves while forming an isosceles triangle with its apex at , and the tip of the support member 50 moves in the direction of arrow X on the left line segment ABC shown in FIG. 3 as shown at points c' and c. Further, the tip of the support member 50 is connected to the line segment ABC on the right side shown in FIG.
'' are moved in a straight line in the same direction, and moved to the far right side to point C, as shown by the solid line on the right side of FIG. While the tip of the support member 50 is moving from the leftmost point C'' to the rightmost point C in FIG. The tube 3 moves linearly in parallel to the direction of the arrow X, and emits X-rays to the subject 12 during this movement.

This is the operation of the radial movement range 1 in FIG.

Thereafter, when the rotation disk 28 and the sun gear 39 are further rotated in the same direction, the planetary gear 45 further revolves in the direction of the arrow E, and this time, the tip of the support member 50 is at the most extreme point in FIG. Turn around at point C on the right side and move in the direction of arrow X. Then, by performing the movement operation exactly as described above, the tip of the support member 5o moves to the leftmost point c'' in FIG. 5, and then turns back again at this point C'' and moves in the direction of the arrow X. . Thereafter, by repeating this operation, the X-ray tube 3 attached via the support shaft 51 at the tip of the support member 50 performs continuous reciprocating linear motion and moves on a linear trajectory.

Next, in order to decelerate and stop after completing the radial movement on such a linear trajectory, as shown in FIG. It's a good idea to apply the brakes when you start moving. Then, as the rotating disk 28 and the sun gear 339 rotate, the planetary gear 45 and the support member 50 sequentially move while decelerating along the paths shown by the dash-dot line and the chain double-dashed line. The tip of the supporting member 50 is connected to the third
The line segment A B CJl on the right side shown in the figure decelerates in the direction of the arrow y2, passes through the point C', reaches the point 0'', and stops at this point C11, for example.As a result, the tip of the support member 50 is supported. The X-ray tube 3 attached via the shaft 5] stops at the trailing edge of the above-mentioned continuous reciprocating linear movement.This is the movement in the deceleration movement range Q in FIG.

In the explanation of FIGS. 4 to 6, it is assumed that the tip C of the support member 50 is started and accelerated in the direction of the arrow X, and then decelerated and stopped. However, the present invention is not limited to this. It is also possible to decelerate and stop at the same time. Further, the respective starting positions or deceleration starting positions are not limited to those shown in the drawings, and may be performed from any position in the revolution of the planetary gear 45.

Furthermore, the linear trajectory mechanism shown in FIG. 2 is only an example of a mechanism for implementing the method of the present invention, and any mechanism that can implement the X-ray tube movement method shown in FIG. 1 may be used. It may be.

Effects of the Invention Since the present invention is configured as described above, the acceleration movement range P and deceleration movement range Q of the X-ray tube 3 are absorbed within the distance of the radiation movement range R that emits X-rays to the subject 12. can do. Therefore, the maximum linear movement distance of the X-ray tube 3 is 1. As is clear from FIG. 1, ' is equal to the radiation movement range in which X-rays are actually emitted, and the linear movement distance can be made shorter than that of the conventional example shown in FIG. From this, X
As a line tomography apparatus, the entire apparatus can be downsized.

Further, since the X-ray tube 3 continuously makes reciprocating linear motion in the directions of the arrows X and Y, no impact is applied to the X-ray tube 3 during the reciprocating linear motion. Therefore, shocks and vibrations are not transmitted to the subject 12 through the top plate 13, causing discomfort or anxiety to the patient! j, I can't get it. Furthermore, since there is no impact on the X-ray tube 3, it is possible to eliminate the cause of image quality deterioration of tomographic images.

Furthermore, the acceleration movement range P, which is the rising edge of the movement of the X-ray tube 33, and the deceleration movement range Q, which is the falling edge, are set at arbitrary distances within the radial movement range R, which is continuous reciprocating linear movement. Therefore, there is no need to suddenly accelerate to start up or suddenly decelerate to stop, and there is no need to use a large drive motor with particularly large torque. Therefore, the entire device can be downsized by using a small motor.

Furthermore, there is no need to provide a conventional mechanical stopper (see reference numeral 11 in FIG. 7), and even if the device breaks down, the X-ray tube 3 simply continues its continuous reciprocating linear motion. Therefore, unlike the conventional case, the X-ray tube 3 does not collide with the stopper 11 and is damaged, and safety can be improved.

[Brief explanation of the drawing]

Figure 1 is an explanatory diagram showing the basic concept of the method for moving the X-ray tube of the X-ray tomography apparatus according to the present invention, and Figure 2 shows an example of the linear trajectory mechanism used to carry out the method for moving the X-ray tube of the present invention. FIG. 3 is an explanatory diagram showing the principle of the X-ray tube moving method in the mechanism of FIG. 2, and FIGS. 4 to 6 are explanations showing the movement of the X-ray tube on a linear trajectory. FIG. 7 is a partially sectional side view showing a linear trajectory mechanism of a conventional X-ray tomography apparatus, and FIG. 8 is an explanatory view showing the X-ray tube moving method according to the conventional example. 33...X-ray tube, 12 object, 13 top plate,
14. X-ray image recording medium, 15. Predetermined site, 28
- Rotating disk, 39... Sun gear, 45 - Planetary gear, 50... Support member, 51 Support shaft, ■]... Acceleration movement range, Q... Deceleration movement range, R - Radiation movement range.

Claims (1)

[Claims] An X-ray tube and an X-ray image recording medium, which are supported opposite to each other with a top plate on which a subject is placed, are moved relative to each other in opposite directions on a straight line centered on a predetermined region within the subject. , in an X-ray tube moving method for an X-ray tomography apparatus in which the X-ray tube is moved on a linear trajectory, the X-ray tube is moved in a continuous reciprocating linear motion, and the X-ray tube is started from a stopped position. The acceleration movement range in which the linear movement accelerates and the deceleration movement range in which the linear movement decelerates and stops are defined as the rise of the continuous reciprocating linear movement within the radial movement range in which X-rays are emitted to the subject during the linear movement. A method for moving an X-ray tube of an X-ray tomography apparatus, characterized in that the movement is performed at the time of falling.