JP2952768B1 - X-ray CT system - Google Patents

Abstract

An object of the present invention is to balance operability and safety when changing a gantry angle. A front rack Cf and a rear rack Cr provided on an arm A supporting the gantry do not mesh with a front rotary damper Df and a rear rotary damper Dr attached to a side plate S at a position where the gantry is nearly vertical. The gantry is tilted at high speed without resistance. At a position where the inclination of the gantry is large, the front rack Cf or the rear rack Cr meshes with the front rotary damper Df or the rear rotary damper Dr, so that a resistance force is applied and the tilt speed of the gantry becomes low. [Effect] When there is no possibility of contact with the subject, the tilt speed can be switched so as to increase the tilt speed, and when the possibility of contact with the subject increases, the tilt speed can be switched so as to decrease the tilt speed. Operability and safety can be balanced.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an X-ray CT (Compo
More particularly, the present invention relates to an X-ray CT apparatus capable of appropriately balancing operability and safety when changing the angle of a gantry.

[0002]

2. Description of the Related Art FIG. 11 is a schematic side view showing an example of a conventional X-ray CT apparatus. This X-ray CT apparatus 500
A cradle C on which the subject H is placed, a table T supporting the cradle C, and a gantry G (expressed in a vertical cross section) having a bore Br through which the cradle C carrying the subject H can enter and exit; Side plate S that supports the gantry G so that the angle can be changed between the forward leaning limit and the backward leaning limit.
And a base B for supporting the side plate S. FIG. 12 shows a state where the gantry G is tilted forward to the forward tilt limit. FIG. 13 shows a state in which the gantry G is tilted backward to the backward tilt limit.

As a safety measure, when a touch sensor (not shown) detects a contact with the subject H while the gantry G is changing the angle, the driving means for changing the angle of the gantry G is stopped. This is the case.

[0004]

FIG. 14 shows a gantry G.
FIG. 9 is a characteristic diagram showing the magnitude of the tilt speed of the gantry when the angle of the gantry is changed. As can be seen from FIG. 14, the magnitude of the tilt speed is constant regardless of the angle of the gantry G. However, this has the following problems. (1) When the tilt speed is increased, the angle of the gantry G can be quickly changed and the operability is good. However, since the amount of movement is large, it takes time from detecting a contact to actually stopping to cause a problem in safety. . Further, there is a problem that when the patient is inclined so as to approach the subject H, a great mental pressure is given to the patient. (2) On the other hand, when the tilting speed is reduced, the momentum is small, so that the patient immediately stops and the safety is high, and the feeling of mental pressure given to the patient is reduced. There is a problem that becomes worse. Therefore, an object of the present invention is to provide an X-ray CT apparatus capable of appropriately balancing operability and safety when changing the angle of a gantry.

[0005]

In a first aspect, the present invention provides a gantry capable of changing an angle between a forward lean limit and a backward lean limit, and a gantry tilt speed when changing the angle of the gantry. An X-ray CT apparatus comprising: a tilt speed switching unit that switches at least two stages according to the current angle of the gantry. X of the above first aspect
In the line CT apparatus, the tilt speed can be switched in at least two stages. Therefore, when the gantry is close to vertical and there is no possibility of contact with the subject, the tilt speed is increased, and the tilt of the gantry becomes large, and the If the possibility of contact with the gantry becomes high, by switching the tilt speed to a low speed, it is possible to appropriately balance operability and safety when changing the angle of the gantry.

In a second aspect, the present invention provides an X
In the line CT apparatus, when the tilt speed switching means separates a forward lean limit and a backward lean limit into a forward lean limit side portion, a center portion, and a backward lean limit side portion, the forward lean limit side portion and the backward lean limit side portion are separated. The present invention provides an X-ray CT apparatus characterized in that a resistance force is applied to a tilt limit side portion by a damper means to switch the tilt speed to a lower tilt speed than a tilt speed at a central portion. In the X-ray CT apparatus according to the second aspect, the tilt speed is switched to a low speed between the forward lean limit side portion and the backward lean limit side portion by using the damper means. There is no need to perform this, and the configuration can be simplified.

According to a third aspect, the present invention provides an X
In the X-ray CT apparatus, the tilt speed switching means switches the tilt speed by switching an output of a driving means for changing an angle of the gantry, and provides an X-ray CT apparatus. In the X-ray CT apparatus according to the third aspect, since the tilt speed is switched by controlling the output of the driving means, for example, an advanced speed control that smoothly (continuously or in multiple stages) switches the tilt speed is provided. Becomes possible.

According to a fourth aspect, the present invention provides an X
In the line CT apparatus, the tilt speed switching means reduces the tilt speed when changing the angle of the gantry in a direction to increase the tilt of the gantry, and sets the tilt speed when changing the angle of the gantry in the direction to decrease the tilt of the gantry. The present invention provides an X-ray CT apparatus characterized by speeding up. In the X-ray CT apparatus according to the fourth aspect, when the inclination of the gantry is increased, there is a possibility of contact with the subject. Therefore, the tilt speed is switched to a low speed. The tilt speed was changed to high speed because there is no possibility of contact. This allows
Operability and safety when changing the angle of the gantry can be appropriately balanced.

[0009]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, the present invention will be described in more detail with reference to the embodiments shown in the drawings. Note that the present invention is not limited by this. -First Embodiment- FIG. 1 is a side view showing an X-ray CT apparatus according to a first embodiment of the present invention. The X-ray CT apparatus 100 includes a gantry G (a two-dot chain line) having a cradle C on which the subject H is placed, a table T supporting the cradle C, and a bore Br through which the cradle C on which the subject H is placed can enter and exit. And a side plate S that supports the gantry G so that the angle can be changed between the forward tilt limit and the backward tilt limit, and a base B that supports the side plate S. I have. The mechanism for supporting the gantry G so that the angle can be changed is such that an arm A is fixed to the gantry G, a front roller Rf and a rear roller Rr are attached to the side plate S,
The arm bottom Ab of the arm A is supported by the front roller Rf and the rear roller Rr.

FIG. 2 is a side view of a mechanism for supporting the gantry G so that the angle can be changed. FIG. 3 is a rear view of the same. The hydraulic cylinder Y is attached across the arm A and the side plate S. As shown in FIG.
By retracting the rod YL, the arm A can be tilted forward. Further, as shown in FIG.
By projecting L, the arm A can be tilted backward.

Returning to FIG. 2, a front rack Cf and a rear rack Cr are provided at both ends of the arc-shaped arm bottom Ab, respectively.
Is fixed. FIG. 4 shows the side plate S.
When the arm A is tilted forward as shown in FIG.
And a rear rotary damper Dr that can mesh with the rear rack Cf when the arm A is tilted rearward as shown in FIG.

The front rotary damper Df has a direction,
When the angle is changed in a direction to increase the inclination of the arm A, the rotational speed of the arm A is reduced by adding a resistance force to the rotational force given from the front rack Cf.
When the angle is changed in a direction to decrease the inclination of the arm A, the rotational force of the arm A is not reduced and the rotational speed of the arm A is not reduced. Similarly, the rear rotary damper Dr has directionality, and applies a resisting force to the rotational force given from the rear rack Cr when changing the angle in a direction in which the inclination of the arm A is increased. Although the speed is decreased, the rotational speed of the arm A is not reduced without applying a resistance to the rotational force given from the rear rack Cr when the angle is changed in a direction to decrease the inclination of the arm A.

FIG. 6 is a characteristic diagram showing a rotation speed characteristic of the arm A, that is, a switching characteristic of the tilt speed when the angle of the gantry G is changed. A portion between the forward lean limit and the backward lean limit is a forward lean limit side portion (the front rack Cf is the front rotary damper Df).
And a central portion (a region where the front rack Cf and the rear rack Cr do not mesh with the front rotary damper Df and the rear rotary damper Dr) and a rear tilt limit portion (a region where the rear rack Cr meshes with the rear rotary damper Dr). When the current angle of the gantry G is at the center, the tilt speed is high because there is no resistance by the front rotary damper Df and the rear rotary damper Dr. When the current angle of the gantry G is on the forward tilt limit side, when the angle of the gantry G is changed in a direction to increase the tilt of the gantry G, the tilt speed decreases because of the resistance by the front rotary damper Df. When the angle of the gantry G is changed in a direction to decrease the inclination of the gantry G, the tilt speed is high because there is no resistance due to the front rotary damper Df. Similarly, when the current angle of the gantry G is on the rearward tilt limit side, when the angle of the gantry G is changed in a direction to increase the tilt of the gantry G, the tilt speed is reduced due to resistance by the rear rotary damper Dr. However, when the angle of the gantry G is changed in a direction to decrease the inclination of the gantry G, the tilt speed is high because there is no resistance by the rear rotary damper Dr.

According to the X-ray CT apparatus 100 described above, when the gantry G is close to vertical or when the angle is changed in a direction in which the inclination of the gantry G is reduced, the tilt speed is increased and the operability is improved. (Since there is no possibility of contact with the subject, there is no problem in safety). Further, when the inclination of the gantry G is further increased from a large angle, the tilt speed becomes low, safety can be secured, and the feeling of mental pressure on the subject H can be reduced.

Second Embodiment FIG. 7 is an explanatory view of a mechanism for supporting a gantry so as to be able to change its angle in an X-ray CT apparatus according to a second embodiment of the present invention. In this X-ray CT apparatus, the angle of the arm A is changed by the chain CH, the drive gear Gy, and the motor M. That is, one end t1 and the other end t2 of the chain CH are fixed to the front end and the rear end of the lower side surface of the arm A, and the drive gear Gy installed on the side plate S, the front sprocket Sf, and the rear sprocket Sr. The side of the chain CH is wound. When the motor M rotates the drive gear Gy, the angle of the arm A is changed.

The angle of the arm A is detected by a rotary encoder re, and the rotation speed of the motor M is switched by the control device CL in accordance with the detected angle of the arm A. This switching is performed, for example, when the forward leaning limit and the backward leaning limit are divided into a forward leaning limit side portion, a center portion, and a backward leaning limit side portion, the center portion is set to a constant high speed, and the forward leaning limit side portion is set. When the rotary drive is performed in the direction of increasing the tilt of the arm A between the forward lean limit and the backward tilt limit side, when the rotational drive is performed in a direction in which the speed is reduced and the tilt of the arm A is reduced as the forward lean limit or the backward tilt limit is approached. Is a constant high speed.
Thereby, for example, the rotation speed characteristic of the arm A, that is, the switching characteristic of the tilt speed when the angle of the gantry G is changed as shown in FIG. 8 is obtained.

According to the above X-ray CT apparatus, the gantry G
When the angle is close to vertical or when changing the angle in the direction to decrease the inclination of the gantry G, the tilt speed becomes high,
Operability is improved (there is no possibility of contact with the subject, so there is no problem in safety). Further, when the inclination of the gantry G is further increased from a large angle, the tilt speed becomes low, safety can be secured, and the feeling of mental pressure on the subject H can be reduced.

When a power cylinder is used as a driving means for changing the angle of the gantry, the same electrical output control as described above may be performed.

-Third Embodiment- In the X-ray CT apparatus according to the third embodiment of the present invention, the mechanism for supporting the gantry so that the angle can be changed is shown in FIGS. 2 and 3 by a front rack Cf, a rear rack Cr, The front rotary damper Df and the rear rotary damper Dr are omitted, and such mechanisms are provided on the left and right side surfaces of the gantry G, respectively.

FIG. 9 is a hydraulic circuit diagram for controlling the hydraulic cylinder. The right hydraulic cylinder YR is the hydraulic cylinder Y of the mechanism provided on the right side of the gantry G.
The left hydraulic cylinder YL is the hydraulic cylinder Y of the mechanism provided on the left side of the gantry G. When projecting the rod of the right hydraulic cylinder YR, the first hydraulic chamber CYR
And discharges the oil in the second hydraulic chamber NYR. When retracting the rod, reverse the procedure. When projecting the rod of the left hydraulic cylinder YL, oil is injected into the first hydraulic chamber CYL and oil is discharged from the second hydraulic chamber NYL. When retracting the rod, reverse the procedure.
The injection and discharge of oil are performed by the valve controller VC controlling the opening and closing of the valves V1 to V6 of the valve unit VU.

FIG. 10 is a table showing the open / closed states of the valves V1 to V6 under the open / close control of the valve controller VC. First, when the angle of the gantry G is not changed, all the valves V1 to V6 are closed. Next, when the angle is changed in the direction to approach the forward leaning limit (including the case where the backward leaning posture is returned to the vertical posture) and the current angle is on the forward leaning limit side portion, only the valves V1 and V6 are opened. , And others are “closed”. Since the oil is injected only from the valve V1, the tilt speed is relatively low. Next, when the angle is changed in a direction to approach the forward leaning limit (including the case where the vehicle is returned from the backward leaning posture to the vertical posture) and the current angle is not at the forward leaning limit side, the valves V1, V2, and V6 are opened. And the others are "closed". Since oil is injected from the valves V1 and V2, the tilt speed becomes relatively high. Next, when the angle is changed in the direction to approach the backward leaning limit (including returning from the forward leaning posture to the vertical posture) and the current angle is not at the backward leaning limit side,
The valves V3, V4 and V5 are set to "open", and the others are set to "closed". Since the oil is discharged from the valves V4 and V5, the tilt speed becomes relatively high. Next, when the angle is changed in a direction to approach the backward leaning limit (including returning from the forward leaning posture to the vertical posture) and the current angle is on the backward leaning limit side portion,
Only the valves V3 and V4 are "open", and the others are "closed".
Since the oil is discharged only from the valve V3, the tilt speed is relatively low.

According to the above X-ray CT apparatus, the gantry G
When the angle is close to vertical or when changing the angle in the direction to decrease the inclination of the gantry G, the tilt speed becomes high,
Operability is improved (there is no possibility of contact with the subject, so there is no problem in safety). Further, when the inclination of the gantry G is further increased from a large angle, the tilt speed becomes low, safety can be secured, and the feeling of mental pressure on the subject H can be reduced.

[0023]

According to the X-ray CT apparatus of the present invention, the tilt speed can be switched to at least two stages. Therefore, when there is no possibility of contact with the subject, the tilt speed is increased and the contact with the subject is increased. When the possibility of performing the operation increases, the tilt speed can be switched so as to reduce the tilt speed, so that operability and safety when changing the angle of the gantry can be appropriately balanced.

[Brief description of the drawings]

FIG. 1 is a side view showing an X-ray CT apparatus according to a first embodiment of the present invention.

FIG. 2 is a side view of a mechanism that supports the gantry so that the angle can be changed.

FIG. 3 is a rear view of a mechanism that supports the gantry so that the angle can be changed.

FIG. 4 is a side view of a mechanism that supports the gantry so that the angle can be changed when the arm is tilted forward.

FIG. 5 is a side view of a mechanism that supports the gantry so that the angle can be changed when the arm is tilted backward.

FIG. 6 is a characteristic diagram of speed switching according to the first embodiment of the present invention.

FIG. 7 is a side view of a mechanism according to a second embodiment of the present invention for supporting a gantry so that the angle can be changed.

FIG. 8 is a characteristic diagram of speed switching according to the second embodiment of the present invention.

FIG. 9 is a hydraulic circuit diagram according to a third embodiment of the present invention.

FIG. 10 is a table showing an open / closed state of a valve in the hydraulic circuit of FIG. 9;

FIG. 11 is a side view of a conventional X-ray CT apparatus.

FIG. 12 is a side view of the X-ray CT apparatus with the gantry tilted forward.

FIG. 13 is a side view of the X-ray CT apparatus with the gantry tilted backward.

FIG. 14 is a characteristic diagram of speed switching in a conventional X-ray CT apparatus.

[Explanation of symbols]

100: X-ray CT apparatus A: Arm, S: Side plate, Cf: Front rack, C
r: rear rack, Df: front rotary damper, Dr: rear rotary damper, Y: hydraulic cylinder, M: motor, re: rotary encoder, CL: control device, V1 to V6: valve, VC: valve controller.

Claims (1)

(57) [Claims] 1. A gantry whose angle can be changed between a forward lean limit and a backward lean limit, and a gantry tilt speed for changing the angle of the gantry is switched to at least two stages according to a current angle of the gantry. It has a tilt speed switching means, and when the forward lean limit and the backward lean limit are divided into a forward lean limit portion, a center portion, and a backward lean limit portion, a tilt speed in the central portion, An X-ray CT apparatus, wherein a tilt speed in the forward lean limit portion and a tilt speed in the backward lean limit portion are different.