JP4751663B2 - X-ray CT system - Google Patents

Description

  The present invention relates to an X-ray CT (Computed tomography) apparatus comprising a rotating part that rotates for imaging and a support part that supports the rotating part, and in particular, an X-ray tube that emits X-rays in order to obtain a tomographic image; The present invention relates to a rotating part structure having a detector for detecting X-rays.

  As disclosed in Patent Document 1, the rotating part of the conventional X-ray CT apparatus has a plate structure in which a disk-like plate on which a load is placed is framed around the disc. As will be described in detail later, the X-ray CT apparatus requires a high-speed rotation in order to obtain a high-quality image, and therefore requires an even lighter and higher-strength structure. However, in the conventional plate structure, when the strength is increased, the rate of increase in mass is large, and there is a limit in achieving the purpose of maintaining the strength and further reducing the weight.

JP-A-9-56710

  In an X-ray CT apparatus, a tomogram is obtained by continuously rotating a rotating unit including an X-ray tube and a detector around a subject. For this reason, the imaging time depends on the rotation speed of the rotating part. If the imaging time is long, the object moves and artifacts due to movement cannot be obtained. It is necessary to raise. However, when the speed of the rotating part increases, the centrifugal force increases in proportion to the square of the rotating speed, and at the same time, the deformation of the rotating part also increases. For this reason, in order to withstand centrifugal force, it is necessary to provide a high-strength structure and reduce deformation. At the same time, to increase the speed, it is necessary to reduce the rotational inertia, that is, to reduce the weight.

  An object of the present invention is to provide an X-ray CT apparatus capable of high-speed rotation and obtaining a high-quality image by using a highly rigid and lightweight load support structure.

The present invention relates to an X-ray CT apparatus having a rolling part to which an imaging mounted object is attached and which rotates around an axis.
The rotating unit is an X-ray CT apparatus configured with an imaging mounting object mounting member for mounting the imaging mounting object and a frame in which a connecting member for connecting the imaging mounting object mounting member to the slip ring mounting part is combined with a rod-shaped member I will provide a.

  According to the above configuration, since the load supporting part of the rotating part has a frame structure combining rod-shaped members, a highly rigid and lightweight rotating part can be configured, high-speed rotation is possible, and high-quality images can be obtained. Can be obtained.

  An embodiment of the present invention will be described with reference to FIGS. First, the structure of the X-ray CT apparatus will be described with reference to FIGS. As shown in FIG. 13, the X-ray CT apparatus includes a gantry 30 having an opening 31 for inserting a subject, a bed 40 for placing the subject, imaging data processing, and various devices. The computer part 50 which controls operation | movement is comprised.

  The bed 40 is provided with a drive unit 41 for placing a subject and moving the subject horizontally and vertically. Thereby, positioning of an imaging part and getting on and off of a patient's bed 40 can be performed easily. The computer unit 50 includes an image processing device 51 for reconstructing an image from X-ray projection data, an image display device 53 for displaying the reconstructed image, and an image storage for recording the reconstructed image on a magnetic disk or the like. The apparatus 52 includes an operation unit 55 for operating / setting the X-ray CT apparatus, and a control unit 54 for controlling various devices necessary for imaging.

  As shown in FIG. 14, the inside of the gantry is composed of many devices. A slip ring 80 having a mechanism for transmitting data and electric power and allowing the X-ray CT apparatus to continuously rotate, a rotating part 10 rotating through the slip ring 80, and a support part for supporting the rotating part 10 70. As shown in FIG. 15, the support unit 70 includes a center frame 71 to which the slip ring 80 is attached, a main frame 72 to which the center frame 71 is attached, side frames 73 attached to both sides of the main frame 72, and side frames. A stand 74 is connected to 73 through a bearing 75. As shown in FIG. 16A of the gantry perspective view and FIG. 16B of the gantry side view, at this time, the rotating portion 10, the center frame 71, the main frame 72, and the side frame 73 are attached to both sides. It is rotated around one bearing 75 and tilted back and forth in the axial direction.

  As shown in FIG. 14, the rotating unit 10 includes an X-ray tube 21 for emitting X-rays, a cooler 22 for cooling the X-ray tube 21 using insulating oil, and the like, from alternating current to direct current. A converter 23 that converts from DC to AC, a high voltage transformer 25 that converts high voltage, a detector 27 that is attached to detect X-rays that have passed through the subject, and a detection A DAS (data collection unit) 28 (contained in 27) that converts analog data into digital data so that the data from the vessel can be processed by a computer, and a load comprising a balance weight 24 that reduces unbalance power, and these It is composed of a load support unit 60 that is installed in a cylindrical shape by combining plate structures, on which all the load is set.

  Next, an imaging method of the X-ray CT apparatus will be described. Referring to FIG. 13, first, in order to position a portion to be imaged, a subject is placed on the bed 40 and inserted into the opening 31 of the gantry by the bed drive unit 41.

  Next, with reference to FIG. 14, electric power is supplied to the rotating part via the slip ring 80. In the converter 23, the supplied power is converted from alternating current to direct current, and is converted again into alternating current by the inverter 26 to obtain a voltage having a flat waveform. This is converted into a high voltage necessary for X-ray radiation by the high voltage transformer 25 and given to the X-ray tube 21. Based on this electric power, the X-ray tube 21 irradiates the subject with X-rays, and the detector detects the X-rays that have passed through the subject.

  In order to obtain a tomographic image, projection data obtained by emitting X-rays to the subject from all angles is required. Therefore, it is necessary to rotate the rotating part including the X-ray tube. As shown in FIG. 17A of the gantry cross-sectional view and FIG. 17B in which only the gantry rotating part is viewed from the back, the servo motor 82 and the rotating part 10 are connected by a belt 81. In order to drive the rotating unit 10, electric power is supplied to the servo motor 82 and power is transmitted to the rotating unit 10 via a belt.

  Thereafter, the detected data is sent from the DAS to the computer unit for image reconstruction.

  In this way, the tomographic image is obtained when the rotating unit including the X-ray tube makes a round around the subject, and the imaging time depends on the speed of the rotating unit. If the imaging time is long, the object moves and the image is blurred and a high-quality image cannot be obtained. Therefore, it is necessary to increase the rotation speed of the rotating unit. However, when the speed of the rotating part is increased, the centrifugal force increases in proportion to the square of the rotating speed, and the deformation of the rotating part also increases. For this reason, it is necessary to make a rotation part into a high intensity | strength structure and to reduce a deformation | transformation.

  In order to reach a rotational speed at which imaging can be performed in a short time, it is necessary to reduce the rotational inertia of the rotating unit, that is, to reduce the weight.

  A conventional gantry structure is shown in FIG. As described in Patent Document 1, the conventional load support unit 60 has a plate structure in which a disk-shaped plate on which the mounts 21 to 27 are installed is framed around the disk. In the X-ray CT apparatus, since the main load acting during operation is a centrifugal force, high rigidity is required in the radial direction, but the rigidity in the other direction may be lower than that. However, the conventional plate structure is not suitable for realizing a shape having a difference in rigidity depending on the direction, and in order to obtain a high quality image, the strength in the radial direction is maintained and the entire structure is reduced in weight. There was a limit to achieving this goal.

  An X-ray CT apparatus equipped with a rotating unit to which an imaging mounted object is attached and which rotates about an axis, the rotating unit slips the imaging mounted object mounting member to which the imaging mounted object is mounted and the imaging mounted object mounting member The connecting member connected to the ring mounting portion has a feature that is configured as a framework in which rod-like members are combined, that is, a frame shape.

In the embodiment of the present invention, the load support 60 is not a conventional plate structure, but is a frame structure by combining rod-like members called beams and truss members in the field of structural mechanics. A first embodiment of the present invention will be described with reference to FIGS. 1 is a perspective view of the entire rotating part of the X-ray CT apparatus of the present invention, FIG. 2A is a perspective view in the vicinity of the X-ray tube, and FIG. 2B is a side view in the vicinity of the X-ray tube. is there. In FIG. 1, the rotating unit 10 is composed of eight units, and one of the imaging mounted objects is arranged and attached to each unit, and rotates about the axis. Each unit is a framework in which an imaging mounting object mounting member 1 for mounting an imaging mounting object and a connecting member 2 for connecting the imaging mounting object mounting member 1 to a slip ring mounting part 11 arranged around the shaft are combined with a rod-shaped member 12. It is composed of three. As shown in FIG. 1, the connecting member 2 is attached over the entire peripheral surface of the slip ring attaching portion 11. The outline of the framework is indicated by 4. Therefore, in FIG. 1, the imaging mounted object mounting member 1 and the rod-shaped member 12, and the connecting member 2 and the rod-shaped member 12 indicate the same part. And in the thing of the structure shown in FIG. 1, although the imaging mounting object attachment member 1 and the connection member 2 are comprised by the integrated object, the structure comprised as a different body and made into a connection body may be sufficient. .

を用いる。骨組みの各ユニットの骨組み３および各ユニット３に取り付けられる各撮像搭載物２１〜２６の各重心は、骨組みの各ユニットの骨組み３の外形線（鎖線）内に位置するように各ユニット３に各撮像搭載物２１〜２６がスリップリング取付部に指向するようにして取り付けられる。これにより、回転によって搭載物に遠心力が働くとき、スリップリング取付部１１に放射状に取り付けられた棒状の部材１２には、主に、引っ張り荷重が、かかるようになる。板構造ではなく、引っ張り圧縮方向に剛性が高い棒状の部材１２で骨組構造とすることにより、遠心力が働く半径方向には剛性を高くし、従来の構造物よりも軽量な形状が得られる。 Note that an intermediate member 5 is placed between the X-ray tube 21 that is the mounted object and the imaging mounted object mounting member 1. The balance weight 24 is directly attached to the imaging mounted object attaching member 1. The member width of the connecting member 2 is the same as the plate width of the slip ring mounting portion 11. The rotating part 10 of the X-ray CT apparatus is a group of units (eight in the case of FIG. 1) composed of a U-shaped frame 3 by combining rod-shaped members 12, and an imaging load is placed on the frame 3 of each unit. The frame structure which carries 21-26 is formed. In the case of FIG. 1, this skeleton is configured as a rectangular frame shape of each independent shape, and since an imaging mounted object is mounted on this frame body, it is suitable for receiving centrifugal force acting in the radial direction. . As shown in FIG. 1, one of the imaging mounted objects is attached to an attachment member 1 constituting one side of the frame. It is not limited to a rectangle, and may be another polygon. The rotating part 10 includes a slip ring mounting part 11 and rotates and slides between the rotating part 10 and the slip ring 80. The detector 27 is installed on the slip ring mounting portion 11 so as to face the X-ray tube. In this embodiment, the rod-shaped member 12 has a T-shaped cross section. The mounted object includes an X-ray tube 21, a cooler 22, an inverter 26, a converter 23, a transformer 25, a balance weight 24, and a detector 27. When attaching the imaging mounted objects 21 to 26, as shown in FIGS. 2A and 2B, the imaging mounted objects 21 to 26 are attached so that the center of gravity fits in the part surrounded by the rod-shaped member 12 (part 4 surrounded by a thick chain line). . The symbol for the center of gravity is

Is used. The frame 3 of each unit of the frame and the center of gravity of each imaging mounted object 21 to 26 attached to each unit 3 are placed in each unit 3 so that it is located within the outline (chain line) of the frame 3 of each unit of the frame. The imaging mounts 21 to 26 are attached so as to be directed to the slip ring attachment portion . Thereby, when a centrifugal force acts on the load by rotation, a tensile load is mainly applied to the rod-like member 12 that is radially attached to the slip ring attachment portion 11. By using a rod-shaped member 12 having high rigidity in the direction of tension and compression instead of the plate structure, rigidity is increased in the radial direction in which centrifugal force acts and a shape that is lighter than conventional structures can be obtained.

A second embodiment of the present invention will be described with reference to FIG. The same components as those in the first embodiment are denoted by the same reference numerals, and the description of the first embodiment is used. Mainly, different portions are displayed and described. The same applies to other embodiments. As shown in FIG. 3, the mounted object support portion 60 includes a slip ring attachment portion 11 and a rod-like member 12 attached radially to the slip ring attachment portion 11. At this time, the cross section of the rod-shaped member 12 is T-shaped. The imaging mounts 21 to 26 are mounted on the tip of the rod-shaped member 12 using the mounting base 18 , and the detector 27 is mounted on the slip ring mounting portion 11 so as to face the X-ray tube. Thereby, compared with the first embodiment, the number of rod-shaped members is reduced, and a lighter shape can be achieved.

  A third embodiment of the present invention will be described with reference to FIG. As shown in FIG. 4, in this embodiment, the mounted object support portion 60 is configured by combining the rod-shaped member 16 so that the outer periphery is octagonal, and further, the outer periphery of the rod-shaped member 16 from the slip ring mounting portion 11l. Connect the vertices. The outer periphery is not an octagon, but may be another polygon such as a hexagon or a dodecagon. Thereby, since it supports using the member 16 of a rod shape common to an adjacent mounting thing, the number of the rod-shaped members 16 to be used decreases, and a more lightweight shape is obtained. Further, compared to the second embodiment, since the mounted object is surrounded by the rod-shaped member 16, it is excellent in safety when a strong centrifugal force is applied.

  A fourth embodiment of the present invention will be described with reference to FIGS. FIG. 5 is a view showing only the vicinity of the X-ray tube 21 of the load supporting unit 60 combined with the rod-shaped member 13 having an L-shaped cross section. FIG. The case where the cooling pipe 14 is attached is shown. An enlarged view of the circled portion (A portion) is shown in the A portion enlarged view of FIG. In the first embodiment, a rod-shaped member having a T-shaped cross section is used for the frame structure in which the rod-shaped members are combined in a U-shape. However, a rod-shaped member 13 having a L-shaped cross section is used. Thereby, in the case of T-shape, the surface divided into two, 12a and 12b, becomes one surface 13a, and the installation area increases. There is also an advantage that a cooling pipe 14 or the like can be attached to this portion. Therefore, the imaging mounted object mounting member 1 and the connecting member 2 are configured by the rod-shaped member 13. In the figure, 1 (13) and 2 (13) are displayed. FIG. 6B is an enlarged view of a portion A in FIG.

  A fifth embodiment of the present invention will be described with reference to FIG. FIG. 7 shows only the vicinity of the X-ray tube 21 of the mounted object support 60 combined using the rod-shaped member 15 whose cross section is a rectangular tube. In the first and fourth embodiments, rod-shaped members having L-shaped and T-shaped cross sections are used for the frame structure in which rod-shaped members are combined in a U-shape. A rod-like member 15 that is a rectangular cylinder is used. Further, the rod-shaped member 15 may have a cylindrical cross section. Thereby, it becomes a high-strength shape in which the tensile, bending, and torsional rigidity of the rod-shaped member is increased. Therefore, the imaging object mounting member 1 and the connecting member 2 are configured by the rod-shaped member 15 which is a rectangular cylinder. In the figure, 1 (15) and 2 (15) are displayed.

  A sixth embodiment of the present invention will be described with reference to FIGS. FIG. 8 is a view showing only the vicinity of the X-ray tube 21 of the load supporting unit 60 in which the rod-shaped member 13 having an L-shaped cross section is combined, and FIG. 9 is a cooling view in FIG. The case where the pipe 14 is attached is shown. In the second embodiment, a rod-shaped member having a T-shaped cross section is used as the rod-shaped member extending radially, but a rod-shaped member 13 having a L-shaped cross section is used. Thereby, in the case of T-shape, the surface divided into two, 12a and 12b, becomes one surface 13a, and the installation area increases. The cooling pipe 14 etc. can be attached to this part. Therefore, the imaging mounted object mounting member 1 and the connecting member 2 are configured by the L-shaped rod-shaped member 13. In the figure, 1 (13) and 2 (13) are displayed. In this example, an X-ray tube 21 as a mounted object is attached to the upper side of the intermediate material 5 via the intermediate material 5. FIG. 8B is a partially enlarged view of the member shown in FIG.

  A seventh embodiment of the present invention will be described with reference to FIG. FIG. 10 shows only the vicinity of the X-ray tube 21 of the mounted object support 60 combined using the rod-shaped member 15 whose cross section is a rectangular tube. In the second and sixth embodiments, a rod-shaped member having a L-shaped cross section and a T-shaped cross-section is used as a radially extending rod-shaped member. The member 15 is used. Moreover, you may use the rod-shaped member whose cross section is a cylinder. Thereby, it becomes a high-strength shape in which the tensile, bending, and torsional rigidity of the rod-shaped member is increased. The configuration is the same as that of the sixth embodiment, and the description of the drawings is also the same. However, the intermediate material is not installed, and the X-ray tube 21 which is a mounted object is directly attached to the imaging mounted object attaching member 1.

  An eighth embodiment of the present invention will be described with reference to FIG. The rod-shaped members 16 are combined in the same manner as in the fifth embodiment, and two sets of these are used to constitute the mounted object support portion 60. The outer periphery of the frame structure is not an octagon, but may be another polygon such as a hexagon or a dodecagon. In addition, the imaging mounts 21 to 26 are attached to a rod-like member so as to be symmetrical with respect to the axial direction, and the detector 27 is attached to the slip ring attachment portion 11 (11A, 11B so as to face the X-ray tube. ). Thereby, compared with the 3rd example, the whole rotation part becomes a higher intensity shape. In this example, each unit 3 is composed of two sets of an imaging mounting object mounting member 1 and a connecting member 2, and the imaging mounting object mounting member 1 and the connecting member 2 are connected by a lateral member 6 to be integrated. I am trying.

  A ninth embodiment of the present invention will be described with reference to FIG. The rotating part 10 is attached to the slip ring attaching part 11 and the outer periphery of the slip ring attaching part 11 in a radial manner, and further attached to the rotating surface at an angle, and a rod-like member 17 which is inclined and arranged slightly on a flat plate, It is comprised from the imaging mounting objects 21-26 attached to the rod-shaped member 17 which forms an outer frame, and the cooler 27 attached to the slip ring attachment part 11 so as to oppose an X-ray tube. Similarly to the third embodiment, the imaging mounted objects 21 to 26 are attached so that the center of gravity fits in the portion surrounded by the rod-shaped member. The slightly flattened rod-shaped member 17 causes air to flow as shown by the arrows in the figure at the time of rotation, thereby increasing the cooling efficiency of the X-ray CT apparatus. Furthermore, it has an excellent shape in terms of strength. Therefore, the imaging mounted object mounting member 1 and the connecting member 2 are constituted by a radial rod-shaped member 17 and a rod-shaped member 17 forming an outer frame. In the figure, 1 (17) and 2 (17) are displayed.

  In the above embodiment, the rod-shaped member can be made lighter by using fiber reinforced plastics (FRP) in addition to a metal material such as steel or aluminum. In addition, since the frame structure is easy to manufacture members and assemble the frame, the manufacturing cost can be reduced.

1 is an overall view of a rotating part of an X-ray CT apparatus in a first embodiment of the present invention. The perspective view (FIG. 2 (a)) and side view (FIG.2 (b)) in the X-ray tube vicinity of the X-ray CT apparatus rotation part shown in FIG. The whole figure of the X-ray CT apparatus rotation part in the 2nd example of the present invention. The whole figure of the X-ray CT apparatus rotation part in the 3rd example of the present invention. FIG. 2 is a view of the vicinity of an X-ray tube of an X-ray CT apparatus rotating unit using a rod-shaped member having an L-shaped cross section for the X-ray CT apparatus rotating unit shown in FIG. 1. FIG. 6A is an X-ray tube vicinity view (FIG. 6A) of an X-ray CT apparatus rotating portion in which a cooling pipe is attached to a rod-like member having an L-shaped cross section, and an enlarged view thereof (FIG. 6B). The X-ray CT apparatus rotation part shown in FIG. 1 WHEREIN: The X-ray-tube vicinity view of the X-ray CT apparatus rotation part using the rod-shaped member whose cross section is a rectangular cylinder. The X-ray CT apparatus rotating unit shown in FIG. 2 uses a rod-shaped member having an L-shaped section, and the X-ray CT apparatus rotating unit near the X-ray tube (FIG. 8A) and the sectional view (FIG. 8 (b)). The X-ray tube vicinity view (FIG. 9 (a)) and cross-sectional view (FIG. 9 (b)) of the rotating part of the X-ray CT apparatus in which the cooling pipe is attached to the rod-shaped member having the L-shaped cross section shown in FIG. ). The X-ray CT apparatus rotating part shown in FIG. 2 uses a rod-shaped member having a rectangular cross-section, and the X-ray CT rotating part vicinity view (FIG. 10 (a)) and sectional view (FIG. 10 (b)). The whole figure of the X-ray CT apparatus rotation part in the 8th example of the present invention. The whole figure of the X-ray CT apparatus rotation part in the 9th example of the present invention. The external view of the X-ray CT apparatus in the Example of this invention. The perspective view of the gantry internal structure in the conventional X-ray CT apparatus. The perspective view of the support part in the conventional X-ray CT apparatus. The perspective view (FIG. 16 (a)) and the side view (FIG.16 (b)) which showed the inclination mechanism in the conventional X-ray CT apparatus. A perspective view (FIG. 17A) and a side view (FIG. 17B) showing a rotating mechanism of a rotating part in a conventional X-ray CT apparatus.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 ... Imaging mounting object attachment member, 2 ... Connecting member, 3 ... Frame, 4 ... Outline line of frame, 5 ... Intermediate material, 10 ... Rotation part, 11 ... Slip ring attachment part, 12 ... Bar shape whose cross section is T-shaped 13 ... Bar-shaped member whose cross section is L-shaped, 14 ... Cooling pipe, 15 ... Bar-shaped member whose cross-section is a rectangular tube, 16 ... Bar-shaped member, 17 ... Rod-shaped member in an inclined arrangement, 18 ... Installation 21 ... X-ray tube, 22 ... Cooler, 23 ... Converter, 24 ... Balance weight, 25 ... Transformer, 26 ... Inverter, 27 ... Detector, 28 ... DAT, 30 ... Gantry, 31 ... Opening, 40 DESCRIPTION OF SYMBOLS ... Bed, 41 ... Drive unit, 50 ... Computer part, 51 ... Image reconstruction apparatus, 52 ... Image storage apparatus, 53 ... Image display apparatus, 54 ... Control part, 55 ... Operation part, 60 ... Mounted object support part, 70 ... support part, 71 ... sen Frame, 72 ... main frame, 73 ... side frame, 74 ... stand, 75 ... bearing, 80 ... slip ring, 81 ... belt, 82 ... servomotor.

Claims (7)

A rotating unit for rotation about an axis, a plurality X-ray CT apparatus imaging payload is attached to the rotating part of,
The rotating part is composed of a framework combining rod-shaped members,
A plurality of connecting portions of rod-like members that are radially attached to the slip ring attaching portion to which the slip ring is slidably attached, over the entire peripheral surface of the slip ring attaching portion, and the connecting member And an attachment member arranged and attached toward the circumferential direction of the slip ring attachment portion,
A plurality of units are configured by the connecting members radially attached over the entire circumference of the slip ring attachment portion and the attachment members arranged in the circumferential direction of the slip ring attachment portion. An X-ray CT apparatus characterized in that any one of the imaging mounted objects is attached to a member toward the slip ring attachment portion . The X-ray CT apparatus according to claim 1, wherein each unit has a frame shape . 3. The unit according to claim 2, wherein each unit is formed into a frame shape by using a mounting member on each side of a mounting member that is formed in a polygonal shape by surrounding the slip ring mounting portion in a circumferential direction. X-ray CT system. The X-ray CT apparatus according to claim 2, wherein each unit is formed into an independent frame shape over the entire circumference of the slip ring mounting member . 2. The X-ray CT apparatus according to claim 1 , wherein each unit is formed by a mounting base in which the mounting member is mounted at a distal end of the connecting member . The X-ray CT apparatus according to claim 1, wherein the frame structure is a frame structure in which rod-shaped members are combined in a U-shape . 7. The X-ray CT apparatus according to claim 1, wherein the center of gravity of each unit and an imaging mounted object attached to each unit is located inside each unit .

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