JP2009240524A - Photography table and x-ray ct equipment - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a photography table which recognizes a scannable range on a top panel while coping with variation of a home position of the top panel, with a simple structure. <P>SOLUTION: The photography table is provided with a designation part 39 for designating a position Q closer to the photography table 3 side on a space in the z direction just for a maximum movable amount S of a top panel 31 from a scan center SC in a photography space 2b. The position Q is constantly a boundary position within the scannable range of the top panel 31 even when the home position of the top panel 31 changes as long as the top panel 31 is located at the home position. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to an imaging table (table) for moving a subject to an imaging space and an X-ray CT apparatus for imaging the subject using the imaging table.

  When performing X-ray CT imaging, generally, the subject is placed on the top of the imaging table, and the subject is moved in a predetermined direction from the home position (home position), and the subject is imaged in a gantry. Transport to space.

  Since the movable amount of the top plate in the imaging table is finite, the range that can be conveyed to the imaging space is limited in the entire area of the top plate. That is, there is a scanable range on the top board. Therefore, an operator such as a radiographer adjusts the position of the subject with respect to the top plate so that the region of interest of the subject falls within the scannable range on the top plate before taking an image, or sets the scan range as a reference. Set the scan area. For this purpose, it is naturally necessary to know which range on the top plate can be scanned, but this range should be determined geometrically based on the positional relationship between the top plate of the imaging table and the gantry. Can do.

  On the other hand, as a photographing table, there is known a photographing table that has a top plate support portion that supports the top plate so as to be movable in a predetermined direction, and the position of the top plate support portion in the predetermined direction can be changed. . In such an imaging table, when the position of the top support in the predetermined direction changes, the home position of the top also changes in the predetermined direction, and the scanable range on the top changes. The scannable range can be obtained by actually moving the top plate to the gantry side as much as possible and confirming the positional relationship between the gantry and the top plate. However, this operation is complicated and takes time. For this reason, there is a strong demand for knowing the scanable range without such a complicated operation.

In order to meet such a demand, in Patent Document 1, a scanable range on the top plate is calculated by a computer based on the positional relationship between the top plate support portion and the gantry, and a panel (panel) provided along the top plate (panel) ) A photographing table for displaying the range on the display unit has been proposed.
JP 2004-208953 A

  However, since the imaging table of Patent Document 1 includes a calculator for calculating a scannable range and a panel display unit for displaying the scannable range, the arrangement of the control board (board), the panel display unit, and the cable (cable) Detailed design such as wiring is required, and the structure becomes complicated.

  SUMMARY OF THE INVENTION In view of the above circumstances, the present invention provides an imaging table capable of showing a scanable range on the top panel to an operator with a simple structure while adapting to changes in the home position of the top board, and X using the imaging table. An object is to provide a line CT apparatus.

  In a first aspect, the present invention provides an imaging table in which an object is placed in an imaging table that conveys the object to an imaging space of a gantry in an X-ray CT apparatus, and moved in the horizontal direction from a home position. A top plate whose home position can change in the horizontal direction with respect to the gantry, and in the horizontal direction, from a position corresponding to a scan center in the imaging space. An imaging table is provided that includes, on the home position side, instruction means for indicating a predetermined position separated by a maximum movable amount of the top plate.

  Here, the home position means a position where the top plate is farthest from the gantry among positions where the top plate can move when the top plate moves linearly.

  The scan center is the center of the region scanned by the scanning gantry, for example, the rotation center of the X-ray tube in the scanning gantry.

  In a second aspect, the present invention provides the imaging table according to the first aspect, wherein the instruction unit includes an instruction unit that indicates the predetermined position and an instruction unit support unit that supports the instruction unit. .

  In a third aspect, the present invention further includes elevating means for elevating and lowering the top plate, and the instruction unit support means elevates and lowers the instruction unit together with the top plate while maintaining the position in the horizontal direction. A photographing table from two viewpoints is provided.

  In a fourth aspect, the present invention further includes a top plate support portion that supports the top plate, and the elevating means includes a base, an upper frame that supports the top plate support portion, A parallel link mechanism including a first oblique arm connected to the base and the upper frame and forming a parallelogram with the base and the upper frame; The slide unit is slidably coupled to the upper frame along the horizontal direction, and has a half length of the first hypotenuse arm, one end of which is the length of the first hypotenuse arm. A second hypotenuse arm that is pivotally coupled to the intermediate point in the direction at the coupling portion and the other end is pivotally coupled to the slide portion and the coupling portion, and is connected to the slide portion , Fingers supporting the indicating unit Providing the imaging table of the third aspect and a part support.

  In a fifth aspect, the present invention provides the imaging table according to the fourth aspect, wherein the elevating means supports the top plate support portion so as to be movable in the horizontal direction.

  In a sixth aspect, the present invention includes a cover part provided to cover the instruction part, and the cover part has a window part that makes the instruction part visible to an operator. A photographing table according to any one of the third to fifth aspects is provided.

  In a seventh aspect, the present invention relates to the sixth aspect, in which the window portion includes an opening provided on an upper surface of the cover portion, and a transparent or translucent member fitted into the opening. Provide a shooting table.

  In an eighth aspect, the present invention provides the imaging table according to the sixth aspect, wherein the window includes an opening provided on a side surface of the cover.

  In a ninth aspect, the present invention provides the imaging table according to any one of the second to eighth aspects, wherein the instruction unit includes a light emitter.

  In a tenth aspect, the present invention includes a cover portion provided to cover the indication portion support means, and the indication portion support means supports the indication portion with a magnetic force through the cover portion. A photographing table according to any one of the second to fifth aspects is provided.

  In an eleventh aspect, the present invention scans the imaging table according to any one of the first to tenth aspects and the subject conveyed to the imaging space by the imaging table, and X An X-ray CT apparatus including a gantry for collecting line projection data is provided.

  According to the present invention, the instruction means indicates the predetermined position away from the gantry in the horizontal direction in which the top plate moves, the home position side by the maximum movable amount of the top plate. Regardless of the home position of the board, using the position corresponding to the boundary of the scannable range on the top board when the top board is located at the home position, without using a calculator or a display panel, The boundary of the scannable range on the top plate can be indicated, and the scanable range on the top plate can be shown to the operator with a simple structure while responding to changes in the home position of the top plate.

  Embodiments according to the present invention will be described below.

(First embodiment)
First, the overall configuration of the X-ray CT apparatus 1 according to the present embodiment will be described.

  FIG. 1 is an external view of the X-ray CT apparatus 1. As shown in FIG. 1, the apparatus 1 includes a scanning gantry 2, an imaging table 3, and an operation console 4.

  Here, for ease of explanation, the vertical direction is the y direction, the longitudinal direction of the imaging table 3 is the z direction, and the direction perpendicular to the y direction and the z direction is the x direction.

  The scanning gantry 2 has an X-ray imaging system (not shown) including an X-ray tube and an X-ray detector that are opposed to each other with a cavity 2b that is an imaging space. The scanning gantry 2 rotates the X-ray imaging system around the subject conveyed to the cavity 2b, images the subject, and collects projection data.

  The imaging table 3 carries the subject to the cavity 2b of the scanning gantry 2 by placing the subject on the top and moving the top in the z direction.

  The operation console 4 controls the scanning gantry 2 and the imaging table 3 based on the input information of the operator, obtains projection data from the scanning gantry 2, and generates a tomographic image of the subject.

  FIG. 2 is a block diagram showing the overall configuration of the X-ray CT apparatus 1. The scanning gantry 2 includes an X-ray tube 21, a collimator 22 (collimator), an X-ray detector 23, and the like, and constitutes an X-ray irradiation / detection device. X-rays radiated from the X-ray tube 21 are shaped by the collimator 22 into, for example, a fan-shaped X-ray beam, that is, a fan beam X-ray, and irradiated to the X-ray detector 23.

  The X-ray detector 23 has a plurality of X-ray detection elements arranged in an array in the spreading direction of the fan beam X-rays. The X-ray detector 23 is a multi-channel X-ray detector in which a plurality of X-ray detection elements are arranged in an array.

  A data collection unit 24 is connected to the X-ray detector 23. The data collection unit 24 collects detection data of individual X-ray detection elements constituting the detector array. X-ray irradiation from the X-ray tube 21 is controlled by an X-ray controller 25 in the scanning gantry 2.

  The above-described components from the X-ray tube 21 to the X-ray controller 25 are mounted on the rotating unit 26 of the scanning gantry 2. Here, the subject is placed in a recumbent state on the top plate 31 in the hollow portion 2 b located at the center of the rotating portion 26. The rotating unit 26 rotates while being controlled by the rotation controller 25, exposes X-rays from the X-ray tube 21, and detects X-rays of the subject in the X-ray detector 23.

  The operation console 4 includes a console control unit 41, a data collection buffer (buffer) 42, an input / output unit 43, a storage unit 44, and the like. A data collection buffer 42 is connected to the console control unit 41, and the data collection buffer 42 is further connected to the data collection unit 24 of the scanning gantry 2. Here, the data collected by the data collection unit 24 is input to the console control unit 41 through the data collection buffer 42.

  The console control unit 41 performs image reconstruction using a transmission X-ray signal collected through the data collection buffer 42, that is, projection data. A storage unit 44 is also connected to the console control unit 41. The storage unit 44 stores projection data collected in the data collection buffer 42, reconstructed tomographic image information, a program for realizing the functions of the apparatus, and the like.

  An input / output unit 43 is connected to the console control unit 41. The input / output unit 43 includes a display device and an operation device, and displays tomographic image information and other information output from the console control unit 41. The input / output unit 43 is operated by an operator and inputs various instructions, information, and the like from the operation device to the control unit 41. An operator operates the apparatus interactively using a display device.

  Further, the imaging table 3 is connected to the console control unit 41, and the height control of the imaging table 3, the position control of the top board 31, and the like are performed. As a result, the subject on the top 31 is placed at the optimum image acquisition position.

  Here, the configuration of the imaging table 3 will be described in detail.

  3, 4, and 5 are diagrams illustrating the configuration of the imaging table 3. 3 is a side view of the main part of the imaging table 3 viewed in the x direction, FIG. 4 is a rear view of the main part of the imaging table 3 viewed in the z direction, and FIG. It is a perspective view when it sees in the diagonal direction.

  As shown in FIG. 3, the imaging table 3 includes a top plate 31, a top plate support portion 32, an elevating device 50, and a cover portion 51.

  As shown in FIG. 5, the top plate 31 has a placement surface on which the subject is placed.

  As shown in FIG. 3, the top plate support unit 32 supports the top plate 31 so as to be movable in the z direction. Specifically, for example, the top plate support unit 32 supports the top plate 31 with a driving roller (roller) 301 and a roller 302 included in the top plate support unit 32, and rotates a motor (not shown) to drive the driving roller 301. And the top plate 31 is moved in the z direction to move.

  The top plate 31 has a home position, and moves from the home position to the cavity 2b by moving in the z direction. Here, a position where the rear edge A of the top plate 31 overlaps the rear edge B of the top plate support portion 32 in the vertical direction is defined as the home position. Further, the top plate 31 has a limit in the amount of movement from the home position, and can move up to the movement amount S.

  The lifting device 50 includes an upper frame 33, a base 34, first oblique side arms 351 and 352, and an actuator unit 38. The top plate support part 32 is supported by the upper frame 33.

  The base 34 is installed on the floor surface. The first hypotenuse arm 351 has one end coupled to the upper frame 33 by a coupling portion 371 and the other end coupled to the base 34 by a coupling portion 372. Similarly, the first hypotenuse arm 352 has one end coupled to the upper frame 33 by a coupling portion 373 and the other end coupled to the base 34 by a coupling portion 374. The coupling portions 371 to 374 form a rotary joint, and the coupling body can freely rotate in the yz plane of FIG. 3 around the coupling portion. That is, the upper frame 33, the base 34, and the first oblique side arms 351, 352 form a parallelogram-type parallel link mechanism 60 having the base 34 and the upper frame 33 as horizontal arms. The actuator unit 38 is connected between the base 34 and the first hypotenuse arm 352.

  A slide part 36, a second hypotenuse arm 353, an instruction part support 391, and an instruction part 39 are attached to the lifting device 50. The slide part 36 is coupled to the upper frame 33 so as to be slidable along the z direction. The second hypotenuse arm 353 has half the length of the first hypotenuse arm 352. The second hypotenuse arm 353 has one end rotatably coupled to the longitudinal intermediate point of the first hypotenuse arm 351 by a coupling portion 378, and the other end rotated by a slide portion 36 and a coupling portion 377. It is combined freely. The instruction unit support 391 is fixed to the slide unit 36 and supports the instruction unit 39. The instruction unit 39 is formed so as to indicate a position in space with at least a part of the position of the instruction unit 39, and has an arrow shape, for example. In addition, the instruction | indication part support body 391 and the instruction | indication part 39 may be integrally formed. The instruction unit support 391 and the instruction unit 39 hold a relative position with the slide unit 36 and move together with the slide unit 36. In addition, the instruction unit support 391 and the instruction unit 39 are provided so that the instruction unit 39 instructs a fixed position Q that is separated from the imaging table 3 by the maximum movable amount S of the top plate 31.

  It should be noted that the fixed position Q thus determined coincides with the boundary of the scannable range on the top plate 31 when the top plate 31 is located at the home position even if the home position of the top plate 31 changes. Position. The relationship between the position indicated by the instruction unit 39 and the scannable range will be described in detail later.

  As shown in FIGS. 4 and 5, the cover portion 51 is provided so as to cover the top plate support portion 32 and the instruction portion 39. The cover part 51 has a window part 511 that makes the instruction part 39 visible to the operator. Here, the window portion 511 includes an opening portion 512 provided on the upper surface of the cover portion 51, and a transparent member or a semitransparent member 513 fitted into the opening portion 512. The member 513 is, for example, acrylic or glass.

  In addition, the slide part 36, the 2nd oblique side arm 353, the instruction | indication part 39, and the instruction | indication part support body 391 in this embodiment function as an instruction | indication means in this invention. Of these, the slide portion 36, the second hypotenuse arm 353, and the indicator support body 391 function as an indicator support means in the present invention, and the indicator 39 functions as an indicator in the present invention. Further, the upper frame 33, the base 34, and the first hypotenuse arms 351, 352 in this embodiment function as a parallel link mechanism in the present invention.

  The operation of the imaging table 3 will now be described.

  First, the raising / lowering operation | movement of the imaging table 3 is demonstrated. The raising / lowering operation of the imaging table 3 is performed by the expansion and contraction of the actuator unit 38. When the actuator unit 38 is expanded and contracted, the first oblique side arm 351 and the first oblique side arm 352 rotate in the yz plane around the coupling part on the base 374 side while maintaining a parallel state to each other. At this time, the upper frame 33 moves up and down while maintaining a parallel state with respect to the base 34. Thereby, the raising / lowering operation | movement of the imaging table 3, ie, the raising / lowering operation | movement of the top plate 31 and the top-plate support part 32, is performed.

  Next, the operation of the mechanism portion formed by the first oblique side arm 351 and the second oblique side arm 353 will be described.

  FIG. 6A is a diagram showing a configuration of a mechanism portion formed by the first hypotenuse arm 351 and the second hypotenuse arm 353.

  As described above, the second hypotenuse arm 353 has a half length of the first hypotenuse arm 351, and one end thereof is connected to the coupling portion 378 present at the midpoint of the first hypotenuse arm 351. The Further, the coupling portions 371 and 377 are maintained in a substantially horizontal position by the upper frame 33. Under this condition, it is geometrically proved that the triangle formed by the coupling portions 371, 372 and 377 is always perpendicular at the coupling portion 377.

  FIG. 6B illustrates the operation of the mechanism portion shown in FIG. 6A when the imaging table 3 moves up and down. The first hypotenuse arm 351 receives a force rotating around the coupling portion 372 of the base 34 as an operation of the parallel link mechanism by the expansion and contraction of the actuator portion 38. As a result, the coupling portion 371 of the first hypotenuse arm 351 moves in the vertical direction while performing a circular motion around the coupling portion 372. At this time, the upper frame 33 to which the coupling portion 371 is fixed also moves in the same manner as the coupling portion 371.

  On the other hand, since the slide part 36 can move freely only in the z direction of the upper frame 33, that is, in the horizontal direction, the joint part 377 is always kept horizontal with the joint part 371. For example, when the connecting portion 371 is lowered as shown in the operation of FIG. 6B, the triangle formed by the connecting portions 371, 372, and 377 is deformed while maintaining a right angle at the connecting portion 377. I will do it.

  For this reason, the coupling part 377 moves up and down only in the vertical direction without moving in the horizontal direction. As a result, the slide portion 36 to which the coupling portion 377 is fixed, the indicator support body 391 fixed to the slide portion 36, and the indicator portion 39 supported by the indicator support body 391 are also horizontal. It moves up and down only in the vertical direction without moving the direction. That is, the indicator support body 391 and the indicator 39 move up and down together with the top board 31 and the top board support part 32 while maintaining the position in the z direction.

  Accordingly, when the top 31 is moved up and down on the photographing table 3, the top support 22 moves in the z direction, but the instruction unit 39 moves relative to the top support 32 by the same amount in the opposite direction. The operation is performed so as to keep the distance from the scanning gantry 2 constant.

  Next, the relationship between the position indicated by the instruction unit 39 and the scannable range on the top 31 will be described.

  FIG. 7A is a view showing the positional relationship between the imaging table 3 and the scanning gantry 2 when the height H of the upper frame 33 is the height H1, and FIG. It is a figure showing the positional relationship of the imaging | photography table 3 and the scanning gantry 2 when height H is height H2 lower than H1. Here, the positional relationship between the base 34 of the imaging table 3 and the scanning gantry 2 in the z direction is fixed. In consideration of the position in the z direction, a coordinate system is used in which the position in the z direction of the scan center SC in the cavity 2b is the scan center position O, and the direction from here toward the imaging table 3 is a positive direction.

  First, consider the case where the height H of the upper frame 33 is H1, as shown in FIG. In FIG. 7A, the top plate 31 drawn with a broken line represents the top plate 31 when it is located at the home position, and the top plate 31 drawn with a solid line is the maximum movable amount ( Only the stroke length (S) represents the top plate 31 when moved in the z direction and negative direction.

  Here, it is assumed that the distance from the tip of the top plate 31 to the scan center position O when the top plate 31 is located at the home position is D. At this time, since the length R in the z direction of the scannable range on the top plate 31 is the length from the tip of the solid top plate 31 to the scan center position O, it is a distance from the maximum movable amount S of the top plate 31. The length is obtained by subtracting D. That is, the following equation holds.

R = SD (Formula 1)
Therefore, when the top 31 is located at the home position, the position corresponding to the boundary of the scannable range on the top 31 is the distance D and the length R from the scan center position O in the z direction and in the positive direction. The position P1 is moved by the added length. That is, the following equation holds.

Δ (P1−O) = D + R (Formula 2)
Here, when R shown in Equation 1 is substituted into Equation 2, Equation 2 becomes as follows.

Δ (P1-O) = D + R
= D + (SD)
= D + SD
= S (Formula 2 ')
That is, when the top plate 31 is located at the home position, the position P1 corresponding to the boundary of the scannable range on the top plate 31 moves in the z direction and the positive direction by the maximum movable amount S from the scan center position O. It becomes the position.

  Next, consider a case where the height H of the upper frame 33 is H2 (<H1) as shown in FIG. As in FIG. 7A, in FIG. 7B, the top plate 31 drawn with a broken line represents the top plate 31 when it is located at the home position, and the top plate 31 drawn with a solid line is The top plate 31 is shown when moved from the home position in the z direction and negative direction by the maximum movable amount S.

  Here, since the height H of the upper frame 33 is H2 smaller than H1, the top plate support portion 32 moves by ΔD in the z direction and the positive direction by the operation of the link mechanism of the elevating means 50. That is, the distance from the tip of the top plate 31 to the scan center position O when the top plate 31 is located at the home position is D + ΔD. At this time, the length R ′ in the z direction of the scannable range on the top plate 31 is the length from the tip of the solid top plate 31 to the scan center position O, and therefore, from the maximum movable amount S of the top plate 31. The length is obtained by subtracting the distance D + ΔD. That is, the following equation holds.

R ′ = S− (D + ΔD) (Formula 3)
Therefore, when the top plate 31 is located at the home position, the position corresponding to the boundary of the scannable range on the top plate 31 is the distance D + ΔD and the length R ′ from the scan center position O in the z direction and in the positive direction. It becomes the position P2 moved by the length of adding. That is, the following equation holds.

Δ (P2−O) = (D + ΔD) + R ′ (Formula 4)
Here, when R ′ shown in Equation 2 is substituted into Equation 4, Equation 4 becomes as follows.

Δ (P2−O) = (D + ΔD) + R ′
= D + ΔD + (S− (D + ΔD))
= D + ΔD + SD−ΔD
= S (Formula 4 ')
That is, when the top plate 31 is located at the home position, the position P2 corresponding to the boundary of the scannable range on the top plate 31 moves in the z direction and the positive direction by the maximum movable amount S from the scan center position O. It becomes the position.

  Thus, when the top 31 is located at the home position, the position corresponding to the boundary of the scannable range on the top 31 is independent of the height H of the upper frame 33, that is, the home position of the top 31. It can be seen that the position is always moved from the scan center position O in the positive direction by the maximum movable amount S of the top 31 in the z direction.

  That is, the fixed position Q indicated by the instruction unit 39 is a position moved from the scan center position O in the z direction and in the positive direction by the maximum movable amount S of the top board 31, and therefore the top board 31 is stopped at the home position. In this case, it is a position that represents the boundary of the scannable range on the top plate 31, and the instruction unit 39 always indicates this position.

  Therefore, when the top plate 31 is stopped at the home position, the operator confirms the position indicated by the instruction unit 39 so that the boundary of the scannable range on the top plate 31, that is, the top plate 31 is maximized. It is possible to know the position that coincides with the scan center position O in the z direction when the movement is limited. Then, the operator can specify the area on the scanning gantry 2 side from the position indicated by the instruction unit 39 among all the areas in the z direction of the top board 31 as the scanable range on the top board 31. Thereby, the operator can adjust the position of the subject with respect to the top plate 31 so that the region of interest of the subject falls within the scannable range, and can set the scan region based on the scannable range. Become.

  According to the present embodiment configured as described above, the instruction unit 39 instructs a predetermined position away from the scanning gantry 2 toward the home position side in the z direction by the maximum movable amount S of the top 31. The computer uses the fact that the predetermined position is a position corresponding to the boundary of the scannable range on the top plate 31 when the top plate 31 is located at the home position, regardless of the home position of the top plate 31. The boundary of the scannable range on the top plate 31 can be instructed without using a display panel or the like, and the scannable range on the top plate 31 has a simple structure while responding to changes in the home position of the top plate 31. Can be shown to the operator.

  Further, according to the present embodiment, the means for instructing the fixed position is a mechanism portion including an instruction portion 39, an instruction portion support body 391 that supports the instruction portion 39, a slide portion 36, a second hypotenuse arm 353, and the like. Therefore, the fixed position can be indicated only by a mechanical operation, and since there is no failure due to the electric system, the maintainability is good and the power saving design is achieved.

  In addition, according to the present embodiment, the instruction unit 39 moves up and down together with the top plate 31 while maintaining the position in the z direction by the mechanism portion including the slide portion 36, the second oblique side arm 353, and the like. Even if the height changes, the spatial gap (gap) between the indicating unit 39 and the top plate 31 can be kept constant, and the correspondence between the position indicated by the indicating unit 39 and the position on the top plate 31 A state in which the relationship is easy to grasp can be maintained.

  Further, according to the present embodiment, the transparent member or translucent member 513 that fits into the opening 512 is provided, so that liquids such as body fluids and contrast agents of the subject enter the cover 51 from the opening 512. Intrusion can be prevented.

The present invention is not limited to the above-described embodiments, and various modifications can be made without departing from the spirit of the present invention.
(Second Embodiment)

For example, as shown in FIG. 8, the cover 51 may have an opening 512 provided on the side surface thereof, and the indicator 39 may be formed so that a part thereof protrudes outward from the opening 512. . In this case, since the member fitted to the opening part 512 is unnecessary, it is low-cost.
(Third embodiment)

  Further, for example, as shown in FIG. 9, the cover unit 51 is provided so as to cover the instruction unit support 391, and the instruction unit support 391 supports the instruction unit 39 with a magnetic force via the cover unit 51. It may be. In this case, it is not necessary to provide an opening in the cover portion 51, and liquid intrusion can be prevented.

Further, for example, the upper frame 33 may support the top plate support part 32 so as to be movable in the z direction. Even if the top plate support part 32 moves, if the home position of the top board 31 does not change with respect to the top board support part 32, the scanable range on the top board 31 when the top board 31 is stopped at the home position. The position that will represent the boundary of is not changed. Therefore, the present invention can be applied as it is to a photographing table in which the top support 32 is movable.
(Fourth embodiment)

For example, the instruction unit 39 may include a light emitter such as an LED. In this case, the visibility of the instruction unit 39 is increased, and the operator can more clearly specify the position indicated by the instruction unit 39.
(Fifth embodiment)

  Further, for example, as a means for indicating the fixed position, not only mechanical means but also optical means may be used. As a specific example, as shown in FIG. 10, a window portion 511 including an opening portion 512 extending in the z direction and a light scattering member 514 fitted to the opening portion 512 is provided on the upper surface of the cover portion 51. A light emitting portion 55 that emits a light beam 551 in the y direction from the bottom to the top toward the window portion 511 is provided. The light emitting unit 55 is fixed at a position where the distance to the scanning gantry 2 is constant. In this way, the fixed position Q can be indicated by the position where the light beam 511 is irradiated by the window portion 511, and the same effect as in the above embodiment can be obtained without a mechanism portion. As the light scattering member 514, for example, frosted glass or acrylic having the same surface can be considered. As the light emission part 55, LED, a semiconductor laser (laser), etc. can be used, for example.

1 is an external view of an X-ray CT apparatus according to a first embodiment. 1 is a diagram illustrating an overall configuration of an X-ray CT apparatus according to a first embodiment. It is a side view which shows the structure of the principal part of the imaging | photography table by 1st Embodiment. It is a rear view which shows the structure of the principal part of the imaging | photography table by 1st Embodiment. It is a perspective view which shows the structure of the principal part of the imaging | photography table by 1st Embodiment. It is a figure for demonstrating the mechanism part formed by the 1st oblique side arm and the 2nd oblique side arm. It is a figure for demonstrating the relationship between the position which an instruction | indication part points, and a scannable range. It is a rear view which shows the structure of the principal part of the imaging table by 2nd Embodiment. It is a rear view which shows the structure of the principal part of the imaging table by 3rd Embodiment. It is a side view which shows the structure of the principal part of the imaging table by 4th Embodiment.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 X-ray CT apparatus 2 Scanning gantry 3 Imaging table 4 Operation console 21 X-ray tube 22 Collimator 23 X-ray detector 24 Data acquisition part 25 X-ray controller 26 Rotation part 27 Rotation controller 31 Top plate 32 Top-plate support part 33 Upper frame 34 Base 301 Driving roller 302 Rollers 351 and 352 First oblique side arm 353 Second oblique side arm 36 Sliding parts 371 to 377 Coupling part 38 Actuator part 39 Pointing part 391 Pointing part support 41 Console control part 42 Data collection buffer 43 Output unit 44 Storage unit 51 Elevating means 51 Cover unit 511 Window unit 512 Opening unit 513 Transparent / translucent member 514 Light scattering member 55 Light emitting unit 551 Light beam

Claims (11)

In the imaging table for transporting the subject to the imaging space of the gantry in the X-ray CT apparatus,
A top plate that is placed on the subject and moves to the imaging space by moving from the home position in the horizontal direction, the top position of which the home position can change in the horizontal direction with respect to the gantry;
An imaging table comprising: instruction means for instructing a predetermined position away from the position corresponding to the scan center in the imaging space in the horizontal direction to the home position side by the maximum movable amount of the top plate.   The imaging table according to claim 1, wherein the instruction unit includes an instruction unit that indicates the predetermined position and an instruction unit support unit that supports the instruction unit. Further comprising elevating means for elevating the top plate;
The imaging table according to claim 2, wherein the instruction unit support means raises and lowers the instruction unit together with the top plate while maintaining the position in the horizontal direction. Further comprising a top plate support part for supporting the top plate,
The elevating means includes a base, an upper frame that supports the top plate support, and a first oblique arm that is connected to the base and the upper frame and forms a parallelogram with the base and the upper frame. Having a parallel link mechanism,
The pointing portion support means has a slide portion that is movably coupled to the upper frame along the horizontal direction, and has a half length of the first hypotenuse arm, and one end thereof is the first portion. A second hypotenuse arm that is pivotally coupled to the intermediate point in the longitudinal direction of the hypotenuse arm at the coupling portion and the other end is pivotally coupled to the slide portion and the coupling portion; and the slide portion The imaging table according to claim 3, further comprising: an instruction unit support that is connected and supports the instruction unit.   The imaging table according to claim 4, wherein the elevating means supports the top plate support portion so as to be movable in the horizontal direction. A cover part provided to cover the instruction part;
The imaging table according to any one of claims 3 to 5, wherein the cover portion includes a window portion that makes the instruction portion visible to an operator.   The imaging table according to claim 6, wherein the window portion includes an opening portion provided on an upper surface of the cover portion, and a transparent or translucent member fitted into the opening portion.   The imaging table according to claim 6, wherein the window includes an opening provided on a side surface of the cover.   The imaging table according to claim 2, wherein the instruction unit includes a light emitter. A cover portion provided so as to cover the instruction portion support means;
The imaging table according to any one of claims 2 to 5, wherein the instruction unit support means supports the instruction unit with a magnetic force through the cover unit. The imaging table according to any one of claims 1 to 10,
An X-ray CT apparatus comprising: a gantry that scans the subject conveyed to the imaging space by the imaging table and collects X-ray projection data.

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