JP2007325919A - X-ray ct apparatus - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an X-ray CT apparatus preventing the deterioration of the image quality even if rotating a rotary frame attached with an X-ray tube and an X-ray detector at a high speed. <P>SOLUTION: This X-ray CT apparatus disposed with the X-ray tube and the X-ray detector opposed to each other and having a cylindrical rotary frame rotating around a subject, rotatably supports the cylindrical rotary frame to a fixed frame surrounding an outer circumference of its annular part, and interposes a bearing member between the internal circumferential face side of the fixed frame and the outer circumferential face side of the annular part of the cylindrical rotary frame so that, even if the cylindrical rotary frame is going to outward expand by receiving a large centrifugal acceleration when rotating the cylindrical rotary frame at a high speed, rigidity between the fixed frame and the bearing member provided between the fixed frame and the rotary frame prevents it to prevent the displacement of the relative position between the X-ray tube and the X-ray detector and prevent the deterioration of the image quality caused by the position displacement. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

The present invention relates to an X-ray CT apparatus, and more particularly to an X-ray tube or X-ray detector even when the rotational speed of a rotating frame to which an X-ray tube or X-ray detector is attached is increased in a gantry. The present invention relates to an X-ray CT apparatus that prevents displacement and does not cause image degradation even when the speed is increased.

The X-ray CT apparatus irradiates, for example, a fan-shaped X-ray from an X-ray source (X-ray tube) to a subject inserted in the central opening of the gantry, and faces the X-ray source through the subject. Transmitted X-ray data is collected by an X-ray detector arranged at a position, for example, a multi-slice detector. For example, in a helical scan X-ray CT apparatus, an X-ray source (X-ray tube) and an X-ray detector are placed opposite to a rotating frame, and the rotating frame is rotated around the subject and the subject is rotated. The X-ray projection data of the subject irradiated with X-rays from multiple directions is acquired by moving in parallel in the rotation axis direction. The acquired projection data is reconstructed in the X-ray CT apparatus and output and displayed as a computer tomographic (CT) image.

As shown in FIG. 8, the X-ray CT apparatus normally has an X-ray tube 20 and an X-ray detector 30 on the vertical part of the rotating frame 10 in the gantry at positions facing each other through the central opening 10C of the gantry. Installed. The subject P is inserted into the central opening 10C of the gantry. The horizontal cylindrical portion of the rotating frame 10 has a structure that is rotatably supported via a plurality of bearings 60 on the outer peripheral surface of the cylindrical portion of the fixed base 100 fixed to the floor surface. That is, the X-ray tube 20 and the X-ray detector 3 provided at positions facing each other across the central opening 10C of the rotating frame 10.
0 continuously rotates in one direction around the subject P on the top board 70 inserted into the central opening 10C of the gantry. The transmitted X-rays irradiated to the subject P from the X-ray tube 20 via the aperture mechanism 90 are acquired by the X-ray detector 30 as a plurality of X-ray projection data. The rotating frame 10 is further equipped with a high voltage generator for supplying a high voltage to the X-ray tube 20, a cooling device for cooling the X-ray tube 22, and the like.

FIG. 7A is a schematic diagram for easy understanding of the positional relationship between the rotary frame 10 of FIG. 8 and the plurality of bearings 60. As described above, a plurality of devices such as the X-ray tube 20, the X-ray detector 30, the high voltage generator 40, and the cooling device 50 are mounted on the vertical portion of the rotating frame 10 in the gantry. It is rotatably held by the cylindrical part of the fixed base via a plurality of bearings 60 arranged on the inner peripheral surface of the part.

The rotating frame 10 is usually made of an aluminum casting. For this reason, when the rotation speed of the rotating frame 10 is increased in order to increase the inspection efficiency, the rotating frame 1 is moved, for example, in the direction shown by the arrow in FIG. 7B according to the rotational acceleration applied to the weight of the mounted device.
Rotational distortion occurs at zero.

FIG. 7B shows a case where positional displacement occurs in a direction in which a predetermined distance between the X-ray tube 20 and the X-ray detector 30 is shortened due to rotational distortion of the rotating frame 10. Contrary to the illustrated arrow, the X-ray tube 20
Of course, a positional displacement may occur in the direction in which the predetermined distance between the X-ray detector 30 and the X-ray detector 30 increases. When positional displacement occurs in the X-ray tube 20 and the X-ray detector 30 due to the rotational distortion of the rotating frame 10, an error occurs in the acquired image data, and the quality of the reproduced image based on the data is deteriorated. End up. This is a fatal problem for the diagnostic imaging apparatus. For this reason, it has been proposed that a weight is appropriately provided on the rotating frame in order to prevent displacement due to rotational distortion during high-speed rotation of the rotating frame and to keep the balance of the rotating frame stable (see, for example, Patent Document 1). . However, the structure of Patent Document 1 has a problem that the apparatus becomes complicated and large. Further, there is also known one in which a bearing is interposed in a fitting portion between a fixed gantry and a rotary gantry (see, for example, Patent Document 2).

As an X-ray CT apparatus for high-speed imaging, projection data necessary to form one computer tomographic (CT) image by rotating the X-ray tube 20 and the X-ray detector 30 around the subject P once. The rotation time T required for obtaining is currently about 0.5 seconds. That is, the rotating frame of the X-ray CT apparatus for high-speed imaging currently in practical use rotates about twice per second.

In general, the relationship between the rotation time T of the rotating frame and the centrifugal acceleration G is expressed by the following equation (1), where R (cm) is the radius of rotation at which the X-ray source rotates around the subject P.
G = 0.0402 (R / T2) (1)

For example, when the rotation radius R of the X-ray source is 75 cm, the centrifugal acceleration applied to the rotating frame that is rotating increases from Formula (1) to about 12G. That is, in the X-ray CT apparatus for high-speed imaging, a large centrifugal force is applied to various devices such as an aluminum rotating frame, an X-ray tube attached to the rotating frame, an X-ray detector, a high voltage generator, and a cooling device. Will be added.
However, there is a strong demand for further speeding up of the X-ray CT apparatus. For example, there is a desire to reduce the time required for one rotation of an X-ray tube or an X-ray detector attached to the rotating frame to 0.25 seconds, that is, four rotations per second. In this case, even if the rotation radius R remains 75 cm, the centrifugal acceleration applied at the time of high speed rotation reaches about 48 G from the equation (1). Further, if the rotation radius is increased to increase the inspection efficiency, the centrifugal acceleration is further increased.

Due to this large centrifugal acceleration, when rotational distortion as shown in FIG. 7B occurs in the rotating frame 10, positional displacement of the X-ray tube 20 and the X-ray detector 30 attached to the rotating frame 10 occurs. Larger bearings to reduce rotational distortion of the rotating frame even at high speeds,
If the rotating frame 10 is strengthened with iron casting or the like, the rigidity of the rotating frame 10 increases due to the increased rigidity. Therefore, the rotational driving force for stopping the rotating frame is also strengthened, and the braking force for stopping the rotation is also increased. The need to strengthen arises. For this reason, the increase in the size of the bearing and the strengthening of the rigidity of the rotating frame itself have the disadvantage that the entire X-ray CT apparatus is increased in size and weight.
JP-A-8-10250 JP 2002-172112 A

As described above, when the rotational speed of the rotary frame of the X-ray CT apparatus is increased, a greater centrifugal force is applied. However, in recent years, in order to improve the inspection efficiency of the X-ray CT apparatus, the opening diameter of the rotating frame to which the X-ray tube or the X-ray detector is attached is further increased, and the rotating frame is rotated at a higher speed. The demand for an X-ray CT apparatus is extremely strong.

The present invention solves the problems of the high-speed X-ray CT apparatus, suppresses distortion due to high-speed rotation of a rotating frame to which an X-ray source, an X-ray detector, and the like are attached, and degrades the quality of CT images during high-speed rotation. It is an object of the present invention to provide an X-ray CT apparatus capable of increasing the opening diameter of the rotating frame, rotating the rotating frame at a high speed, reducing the weight of the apparatus, and improving the inspection efficiency. Is.

The X-ray CT apparatus according to the first embodiment of the present invention includes an annular portion having a predetermined length in the rotational axis direction, and projects in a direction perpendicular to the rotational axis on the inner peripheral surface of the annular portion. A cylindrical rotating frame having a provided rib portion; an X-ray tube and an X-ray detector arranged opposite to each other with the rotating shaft at a predetermined position of the rib portion of the cylindrical rotating frame; and the rib portion A bearing member arranged in a ring shape so as to surround the outer peripheral surface of the cylindrical rotating frame at a position corresponding to the cylinder, and the cylinder so as to surround the entire outer peripheral surface of the cylindrical rotating frame via the ring-shaped bearing member And a cylindrical rotating frame support part for supporting the rotating frame.

An X-ray CT apparatus according to a second embodiment of the present invention includes a cylindrical rotary frame having an annular portion having a predetermined length in the rotational axis direction, and the rotational shaft at a predetermined position of the annular portion. An X-ray tube and an X-ray detector arranged opposite to each other, and arranged in a ring shape so as to surround the outer peripheral surface of the cylindrical rotating frame at a position passing through the center of gravity of the cylindrical rotating frame and orthogonal to the rotation axis. A plurality of bearing members, and a cylindrical rotating frame support portion that supports the cylindrical rotating frame so as to surround the entire outer peripheral surface of the cylindrical rotating frame via the ring-shaped bearing member,
It is characterized by comprising.

According to the X-ray CT apparatus according to the embodiment of the present invention, when the rotating frame is rotated at an ultra-high speed, even if the rotating frame that has received a large centrifugal acceleration swells outward, the fixed frame and the fixed frame The rotational distortion of the rotating frame can be suppressed by the rigidity of the bearing member provided between the rotating frame and the rotating frame. For this reason, the displacement of the relative position between the X-ray tube and the X-ray detector provided in the rotating frame can be further reduced, and the deterioration of the image quality due to the displacement can be prevented.

  Hereinafter, embodiments of the X-ray CT apparatus according to the present invention will be described.

Hereinafter, a first embodiment of an X-ray CT apparatus according to the present invention will be described in detail with reference to FIGS. In these drawings, the same portions are denoted by the same reference numerals.

FIG. 1 is a sectional view for explaining an embodiment of a cylindrical rotating frame applied to the X-ray CT apparatus of the present invention. The cylindrical rotating frame 1 includes an annular portion 1A that surrounds the frame rotation axis O,
A circular rib portion 1B projecting on the inner peripheral surface of the annular portion 1A at a position on an imaginary line Y passing through the center of gravity G of the cylindrical rotating frame 1 at a substantially center in the annular portion 1A and orthogonal to the rotation axis O; However, it is integrally formed of, for example, aluminum casting. Of course, it can also be integrally formed of iron castings. Ring part 1A
An X-ray tube 2 is disposed at a predetermined position of the circular rib portion 1B protruding inward, and the X-ray detector 3 is placed on the rib portion 1B at a position facing the X-ray tube 2 via the rotation axis O of the cylindrical rotating frame 1. Is installed. X
An X-ray beam irradiated from the X-ray tube 2 so as to center on the center of gravity G of the cylindrical rotating frame 1 passes through the subject P and is detected by the X-ray detector 3. A central portion of the circular rib portion 1B forms an opening 1C so as to pass through the rotation center axis O. The cylindrical rotation frame 1 rotates around the rotation axis O around the subject P on the top plate 7 inserted into the opening 1C, so that projection data in which the X-ray beam has passed through the subject P from multiple directions is obtained. It can be detected by the X-ray detector 3.

In FIG. 1, the cylindrical rotating frame 1 has an embodiment in which the annular portion 1A and the circular rib portion 1B protruding on the inner peripheral surface of the annular portion 1 are integrally formed. In order to make it larger, X is directly applied to the center of the inner surface of the annular portion 1A of the cylindrical rotating frame 1 without providing the circular rib portion 1B
The tube 2 and the X-ray detector 3 may be installed facing each other.

FIG. 2 is a schematic diagram illustrating the configuration of the cylindrical rotating frame 1 of FIG. As shown in the figure, in the cylindrical rotating frame 1 applied to the X-ray CT apparatus of the present invention, an annular portion 1 of the cylindrical rotating frame 1 is used.
At a position corresponding to the circular rib portion 1B on the outer peripheral surface of A, the plurality of bearing members 6 are the annular portion 1A.
It arrange | positions in a ring shape so that the outer peripheral surface may be surrounded. That is, the entire cylindrical rotating frame 1 serves as a rotating shaft, and is rotatably held on the fixed frame via a plurality of bearing members 6 arranged in a ring shape. The center line of the circular rib portion 1B provided at the inner central portion of the annular portion 1A of the cylindrical rotating frame 1 is orthogonal to the rotation axis O and passes through the center of gravity G of the cylindrical rotating frame 1. In the cylindrical rotating frame 1, an X-ray tube 2, an X-ray detector 3, a high voltage generator 4, and a data collecting device, a cooling device, a balance weight, and other devices 5 are fixed at predetermined positions. A plurality of bearings arranged in a ring shape when the cylindrical rotating frame 1 rotates at a high speed by holding a fixed frame so as to surround the entire rotating shaft from the outside via a plurality of bearing members 6 arranged in this ring shape. The deformation of the cylindrical rotating frame 1 is suppressed by the rigidity of the member 6 and the fixed frame.

FIG. 3 is a cross-sectional view showing a specific holding structure of the cylindrical rotating frame 1 shown in FIG. On the outer peripheral surface of the annular portion 1A of the cylindrical rotating frame 1, a circular fixed frame 11 is installed coaxially with the annular portion 1A, and the outer peripheral surface of the circular portion 1A of the cylindrical rotating frame 1 and the circular fixed frame 11 The peripheral surface is rotatably held by a bearing member 6 arranged in a ring shape. In the present embodiment, a plurality of bearing members 6 are provided on the outer peripheral surface of the annular portion 1A of the cylindrical rotating frame 1 in a ring shape at substantially equal intervals. The outer periphery of the circular fixed frame 11 is fixed to a gantry stand 12 having one end fixed to the floor bottom.

A circular fixed frame 11 coaxial with the rotation axis O is supplied with electric power to a motor 13 for rotating the cylindrical rotating frame 1, an X-ray tube 2, an X-ray detector 3 provided on the cylindrical rotating frame 1, and other devices. A ring-shaped fixed-side data transmission unit 14A for supplying and transmitting / receiving data to / from a control unit (not shown) is provided. The cylindrical rotating frame 1 has a fixed data transmission unit 1.
A ring-shaped receiving side data transmission unit 14B is provided opposite to 4A. Normally, power is supplied to each rotating device through a slip ring. Data transmission between the fixed side data transmission unit 14A and the reception side data transmission unit 14B is performed via light.

As the plurality of bearing members 6 arranged between the inner peripheral surface side of the circular fixed frame 11 and the outer peripheral surface side of the annular portion 1A of the cylindrical rotating frame 1, bearing members having various structures are used. 4A.
Is the most common bearing member, which is an iron bearing ball 6a of the bearing member 6.
2 on the vertical imaginary line 6d with respect to the rotating side receiving portion 6b fixed on the outer peripheral surface of the cylindrical rotating frame 1 and the fixed side receiving portion 6c fixed on the inner peripheral surface of the fixed frame 11. The points c1 and c2 are configured to contact each other. That is, when the cylindrical rotating frame 1 rotates at high speed around the center of gravity G, even if centrifugal acceleration is applied in a direction orthogonal to the rotation axis O, the rigidity of the plurality of bearing members 6 and the fixed frame 11 via the bearing members 6 are increased. The deformation of the cylindrical rotating frame 1 can be suppressed by the rigidity.

FIG. 4B is a four-point contact bearing member. Two imaginary lines 6d1 in which the iron bearing balls 6a of the bearing member 6 are inclined by +45 degrees and −45 degrees with respect to the vertical imaginary line 6d in FIG. 4A with respect to the rotating side receiving part 6b and the fixed side receiving part 6c, respectively. , 4 points C1a on 6d2,
This structure is in contact with C1b, C2a, and C2b. Because it is a 4-point contact, there is little rolling resistance,
Since the centrifugal acceleration of the high-speed rotation of the cylindrical rotary frame 1 is distributed and transmitted to the fixed frame 11, the rigidity for preventing the distortion of the rotary frame during high-speed rotation is further increased. The inclination angles of the virtual lines 6d1 and 6d2 may be angles other than 45 degrees.

FIG. 4C is a double row angular contact bearing. Two rows of bearing members 6a1
6a2 are provided in parallel, and one iron bearing ball 6a1 is in contact with the rotating side receiving portion 6b and the fixed side receiving portion 6c at an imaginary line 6d3 of +45 degrees with respect to the vertical imaginary line 6d in FIG. 4A. The other iron bearing ball 6a2 is configured to come into contact with the rotation side receiving portion 6b and the fixed side receiving portion 6c at an imaginary line 6d4 of −45 degrees with respect to the virtual imaginary line 6d in FIG. 4A. Similarly to FIG. 4B, this two-row angular contact bearing also disperses the centrifugal acceleration of the high-speed rotation of the cylindrical rotating frame 1 and transmits it to the fixed frame 11, so that the rigidity against the rotational distortion of the cylindrical rotating frame can be increased and the higher speed can be achieved. Can be realized.

As described above, the cylindrical rotating frame 1 applied to the X-ray CT apparatus of the present invention can be rotated so that the entire outer periphery of the cylindrical rotating frame 1 is surrounded by the fixed frame 11 with the entire cylindrical rotating frame 1 regarded as a rotating shaft. To support. Therefore, when the cylindrical rotating frame 1 is rotated at a high speed, even if it receives a large centrifugal acceleration and the cylindrical rotating frame 1 tries to expand outward, the rigidity of the fixed frame 11 and the fixed frame 11 and the cylindrical rotating frame 1 Bearing member 6 interposed between
Therefore, the rotational distortion of the cylindrical rotary frame 1 can be suppressed. for that reason,
Displacement of the relative position between the X-ray tube 2 and the X-ray detector 3 due to high-speed rotation can be prevented, and deterioration of the quality of the CT image due to this displacement can be prevented.

Further, the cylindrical rotating frame 1 and the fixed frame 11 are moved without moving the rotation center of the cylindrical rotating frame 1 so that the X-ray CT apparatus can perform tomography at various angles with respect to the body axis of the subject. Can be supported by the tilt structure so as to be tilted together with the cylindrical rotating frame 1 over a predetermined angle range.

FIG. 5 shows a tilt mechanism of the cylindrical rotating frame 1 and the fixed frame 11. The fixed frame 11 is held by the tilting frame 121, and the tilting frame 121 can be tilted by the expansion and contraction of the power cylinder 18 and the entire cylindrical rotating frame 1 and the fixed frame 11. By this tilt mechanism, the incident angle of the X-ray beam irradiated from the X-ray source to the subject P can be changed without changing the rotation center of the cylindrical rotating frame 1. That is, according to this embodiment, the cylindrical rotating frame 1
Multi-angle projection data can be obtained while rotating at a high speed.

FIG. 3 shows an embodiment in which the cylindrical rotating frame 1 is formed by integrally forming the annular portion 1A and the circular rib portion 1B protruding on the inner peripheral surface of the annular portion 1A. As described in the above, in order to make the opening 1C larger, the X-ray tube 2 and the X-ray detector 3 are directly connected to the center of the inner surface of the cylindrical portion 1A of the cylindrical rotating frame 1 without providing the circular rib portion 1B. May be installed opposite to each other.

FIG. 6 illustrates a second embodiment of a cylindrical rotating frame structure applied to the X-ray CT apparatus of the present invention. In addition, in order to avoid duplication description, the same code | symbol is attached | subjected to the part same as FIG. 1 thru | or FIG.

In the second embodiment of the rotating frame configuration shown in FIG. 6, a first bearing member 61 is provided between the inner peripheral surface side of the cylindrical fixed frame 11 and the outer peripheral surface side of the annular portion 1A of the cylindrical rotating frame 1. The second bearing member 62 is arranged in a two-row ring shape. The two rows of bearing members 61 and 62 are disposed so as to surround the annular portion 1A with a space therebetween. For example, as shown in the figure, the first bearing member row 61 is arranged in a ring shape at one outer peripheral end of the annular portion 1A of the cylindrical rotating frame 1, and the other outer periphery of the annular portion 1A of the cylindrical rotating frame 1 A second bearing member 62 is arranged in a ring shape at the end.

In the illustrated embodiment, the first bearing member 61 and the second bearing member 62 are shown in FIG.
Two-row angular contact bearings 61 and 62 shown in C are separately arranged on the left and right. That is, the bearing ball 61a of the first bearing member 61 is connected to the rotation side receiving portion 61b.
And a virtual line 61d connecting two contact points in contact with the fixed side receiving portion 61c is a cylindrical rotating frame 1
It is inclined so as to intersect inside the annular portion 1A. Further, a virtual line 62d connecting two contact points where the bearing ball 62a of the second bearing member 62 contacts the rotating side receiving portion 62b and the fixed side receiving portion 62c intersects inside the annular portion 1A of the cylindrical rotating frame 1. It has become so inclined.

According to the present embodiment, when the cylindrical rotating frame 1 is rotated at an ultrahigh speed, even if the cylindrical rotating frame 1 is swelled outward due to a large centrifugal acceleration, the fixed frame 11 and the fixed frame 11 and the cylinder Due to the rigidity of the first and second bearing member members 61, 62 provided between the rotary frame 1, the rotational distortion of the cylindrical rotary frame 1 can be suppressed more strongly. Furthermore, by making the first and second bearing member members 61 and 62 angular contact bearings, the longitudinal rigidity of the cylindrical rotating frame 1 can be increased, and the pitching vibration of the cylindrical rotating frame 1 can be reduced. it can. Therefore, even if the cylindrical rotating frame 1 is rotated at an ultrahigh speed, the displacement of the relative position between the X-ray tube 2 and the X-ray detector 3 can be further reduced, and the deterioration of the image quality can be prevented. .

In the embodiment of FIG. 6, the double row angular contact bearings are used as the double row bearing members 61 and 62, but it is of course possible to use the bearing members shown in FIGS. 4A and 4B.

In the embodiment of FIG. 6, the two rows of bearing members 61, 62 are the rotational axes O of the cylindrical rotary frame 1.
Are arranged at symmetric positions with respect to an imaginary line Y passing through the center of gravity of the cylindrical rotating frame 1. However, even if the two rows of bearing members 61 and 62 are arranged asymmetrically with respect to the virtual line Y, the effect of the present invention can be obtained.

Also in the embodiment of FIG. 6, as shown in FIG. 3, the fixed frame 11 is supplied with electric power to a motor for rotating the cylindrical rotating frame 1 and various devices provided in the cylindrical rotating frame 1. A data transmission unit for exchanging data between them is provided. Further, as shown in FIG. 5, a tilt mechanism for tilting the fixed frame 11 over a predetermined angle range may be provided.

FIG. 6 shows an embodiment in which the cylindrical rotating frame 1 has an annular portion 1A and a circular rib portion 1B that protrudes on the inner peripheral surface of the annular portion 1A. However, in the embodiment of FIG. As described above, in order to make the opening 1C larger, the X-ray tube 2 and the X-ray detector 3 are directly connected to the central portion of the inner surface of the cylindrical portion 1A of the cylindrical rotating frame 1 without providing the circular rib portion 1B. You may make it install facing.

In the second embodiment according to the present invention, the bearing members 61 and 62 are formed by separating two rows on the outer surface of the annular portion of the cylindrical rotating frame 1, but the present invention is not limited to this. A member may be formed.

According to the X-ray CT apparatus according to the first and second embodiments of the present invention, when the cylindrical rotating frame is rotated at an ultra-high speed, the cylindrical rotating frame that has received a large centrifugal acceleration attempts to expand outward. The rotational distortion of the cylindrical rotary frame can be suppressed by the rigidity of the fixed frame and the bearing member provided between the fixed frame and the cylindrical rotary frame. For this reason, the displacement of the relative position between the X-ray tube and the X-ray detector provided in the cylindrical rotating frame can be further reduced, and the deterioration of the image quality due to this displacement can be prevented.

In addition, according to the X-ray CT apparatus according to the first and second embodiments of the present invention, even when the rotational speed of the rotating frame is further increased and the rotating frame receives a larger centrifugal acceleration, the longitudinal direction of the rotating frame The rigidity of the arm can be increased and the pitching vibration can be reduced. Therefore, even if the rotating frame rotates at a higher speed, the displacement of the relative position between the X-ray tube and the X-ray detector can be further reduced, and deterioration of the image quality can be prevented.

Furthermore, according to the X-ray CT apparatus according to the first and second embodiments of the present invention, tilt imaging can be performed by tilting the rotating frame support portion over a predetermined angle range without moving the rotation center of the rotating frame. It becomes.

The present invention may be appropriately modified within a range not departing from the gist of the present invention, such as a combination of the first embodiment and the second embodiment.

1 is a cross-sectional view of a cylindrical rotating frame applied to an X-ray CT apparatus according to a first embodiment of the present invention. The conceptual diagram which shows the relationship between the cylindrical rotating frame of the X-ray CT apparatus of this invention, and the some bearing arrange | positioned on a ring frame outer peripheral surface. Sectional drawing which shows the specific holding structure of the rotation frame applied to the X-ray CT apparatus of this invention shown in FIG. Sectional drawing of the two-point contact bearing which shows an example of the bearing member interposed by the rotating frame holding structure shown in FIG. Sectional drawing of the 4-point contact bearing which is another example of the bearing member interposed by the rotating frame holding structure shown in FIG. FIG. 4 is a cross-sectional view of a two-row angular contact bearing which is still another example of a bearing member interposed in the rotating frame holding structure shown in FIG. 3. FIG. 3 is a partially cut perspective view for explaining an embodiment of a tilt mechanism for the entire rotating frame holding mechanism applied to the X-ray CT apparatus of the present invention. FIG. 5 is a partially cut cross-sectional view for explaining the structure of a second embodiment of a cylindrical rotating frame applied to the X-ray CT apparatus according to the present invention. The schematic diagram explaining the structure of the rotation frame of the X-ray CT apparatus which is the background art of this invention. The schematic diagram explaining the rotational distortion at the time of high speed rotation of the rotating frame shown to FIG. 7A. Sectional drawing explaining the rotation frame holding | maintenance mechanism of the X-ray CT apparatus which is background art of this invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 ... Cylindrical rotation frame, 1A ... Ring part, 1B ... Rib part, 2 ... X-ray tube, 3 ... X-ray detector, 4
... High voltage generator, 6, 61, 62 ... Bearing members, 6a, 6a1, 6a2, 61a,
62a... Bearing ball, 6b, 61b, 62b... Rotation side receiving portion, 6c, 61c, 62
c: Fixed side receiving part, 7 ... Subject, 11 ... Circular fixed frame, 12 ... Gantry stand, 13 ...
Motor, 14A: Fixed side data transmission section, 14B: Reception side data transmission section, 18: Power cylinder, 121: Tilt frame

Claims (17)

A cylindrical rotating frame having an annular portion having a predetermined length in the rotational axis direction, and a rib portion provided on the inner peripheral surface of the annular portion so as to project in a direction perpendicular to the rotational axis;
An X-ray tube and an X-ray detector disposed opposite to each other with the rotation axis in between at a predetermined position of the rib portion of the cylindrical rotating frame;
A bearing member disposed in a ring shape so as to surround the outer peripheral surface of the cylindrical rotating frame at a position corresponding to the rib portion;
A cylindrical rotating frame support part for supporting the cylindrical rotating frame so as to surround the entire outer peripheral surface of the cylindrical rotating frame via the ring-shaped bearing member;
An X-ray CT apparatus comprising: The annular portion and the rib portion of the cylindrical rotating frame are integrally formed,
2. The X-ray CT apparatus according to claim 1, wherein the plurality of bearing members are arranged in a single ring on the outer circumferential surface of the annular portion at a position on the rib portion. The plurality of bearing members are interposed in a single ring at a position that is perpendicular to the rotation axis of the cylindrical rotating frame on the outer periphery of the annular portion of the cylindrical rotating frame and passes through the center of gravity of the cylindrical rotating frame. The X-ray CT apparatus according to claim 1. Each of the plurality of bearing members includes a ball part, a rotating side receiving part fixed to the outer periphery of the annular part of the cylindrical rotating frame, and a fixed side receiving part fixed to the cylindrical rotating frame support part. Configured,
2. The X-ray CT apparatus according to claim 1, wherein the ball portion is in contact with the rotating side receiving portion and the fixed side receiving portion at two points on an imaginary line passing through a center line of the rib portion. . Each of the plurality of bearing members includes a ball part, a rotating side receiving part fixed to the outer periphery of the annular part of the cylindrical rotating frame, and a fixed side receiving part fixed to the cylindrical rotating frame support part. Configured,
The ball part is in contact with the rotating side receiving part and the fixed side receiving part at four points on an imaginary line inclined with respect to a center line of the rib part of the cylindrical rotating frame. The X-ray CT apparatus according to 1. Each of the plurality of bearing members includes a ball part, a rotating side receiving part fixed to the outer periphery of the annular part of the cylindrical rotating frame, and a fixed side receiving part fixed to the cylindrical rotating frame support part. Configured,
The ball portion is a two-row angular contact bearing in contact with the rotating side receiving portion and the fixed side receiving portion at two points on an imaginary line inclined with respect to the center line of the rib portion. The X-ray CT apparatus according to 1. 2. The X-ray according to claim 1, wherein the plurality of bearing members are interposed in an outer periphery of the annular portion of the cylindrical rotating frame in at least two rows at a distance from a center line of the rib portion. CT device. The plurality of bearing members are arranged in one row on the center line of the rib portion on the outer periphery of the annular portion of the cylindrical rotating frame, and are arranged in two rows at a predetermined interval from the center line. The X-ray CT apparatus according to claim 1. 2. The X-ray CT apparatus according to claim 1, wherein the plurality of bearing members are respectively arranged in an annular shape at an outer peripheral end portion of the annular portion of the cylindrical rotating frame. 2. The plurality of bearing members, wherein at least two of the bearing members are arranged in a ring shape, and the two bearing members are arranged on a target with respect to a center line of the rib portion.
X-ray CT apparatus described in 1. At least two of the plurality of bearing members are arranged in a ring shape, and the two bearing members are respectively arranged on the outer periphery of the annular portion of the cylindrical rotating frame by separating a two-row angular contact bearing. The X-ray CT apparatus according to claim 1. At least three of the plurality of bearing members are arranged in a ring shape, and the three bearing members are arranged at a position corresponding to the center line of the rib portion and both outer peripheral ends of the annular portion of the cylindrical rotating frame. The X-ray CT apparatus according to claim 1, wherein: The X-ray CT apparatus according to claim 1, further comprising a tilting mechanism that tilts a rotation axis of the cylindrical rotating frame over a predetermined angular range on the cylindrical rotating frame support. A cylindrical rotating frame having an annular portion having a predetermined length in the rotation axis direction;
An X-ray tube and an X-ray detector that are arranged opposite to each other with the rotation axis in place at a predetermined position of the annular portion;
A plurality of bearing members arranged in a ring shape so as to surround the outer peripheral surface of the cylindrical rotating frame at a position passing through the center of gravity of the cylindrical rotating frame and perpendicular to the rotation axis;
A cylindrical rotating frame support part for supporting the cylindrical rotating frame so as to surround the entire outer peripheral surface of the cylindrical rotating frame via the ring-shaped bearing member;
An X-ray CT apparatus comprising: Each of the plurality of bearing members includes a ball part, a rotating side receiving part fixed to the outer periphery of the annular part of the cylindrical rotating frame, and a fixed side receiving part fixed to the cylindrical rotating frame support part. Configured,
2 on an imaginary line in which the ball portion passes through the center of gravity of the cylindrical rotating frame and is orthogonal to the rotation axis.
The X-ray CT apparatus according to claim 14, wherein the X-ray CT apparatus is in contact with the rotating side receiving portion and the fixed side receiving portion. Each of the plurality of bearing members includes a ball part, a rotating side receiving part fixed to the outer periphery of the annular part of the cylindrical rotating frame, and a fixed side receiving part fixed to the cylindrical rotating frame support part. Configured,
The ball portion is in contact with the rotating side receiving portion and the fixed side receiving portion at four points on a virtual cross line that is inclined with respect to a virtual line that passes through the center of gravity of the cylindrical rotating frame and is orthogonal to the rotation axis. The X-ray CT apparatus according to claim 14, wherein the X-ray CT apparatus is characterized. Each of the plurality of bearing members includes a ball part, a rotating side receiving part fixed to the outer periphery of the annular part of the cylindrical rotating frame, and a fixed side receiving part fixed to the cylindrical rotating frame support part. Configured,
Two-row angular contact in contact with the rotating side receiving portion and the fixed side receiving portion at two points on the virtual cross line that the ball portion passes through the center of gravity of the cylindrical rotating frame and is inclined with respect to the virtual line orthogonal to the rotation axis The X-ray CT apparatus according to claim 14, wherein the X-ray CT apparatus is a bearing.

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