JP2015039384A - Medical bed device and x-ray ct apparatus - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a medical bed device capable of securing safety and provide an X-ray CT apparatus capable of reproducing the position of a top plate with a high degree of precision.SOLUTION: A medical bed device and an X-ray CT apparatus include a bed body, a top plate, top plate transfer means, an intermediate member, intermediate transfer means, and control means. The top plate is mounted with an object to be examined. The top plate transfer means transfers the top plate in a reciprocating manner in a body axial direction with respect to the bed body. The intermediate member is arranged between the bed body and the top plate so as to be transferred in the body axial direction of the object to be examined. The intermediate transfer means transfers the top plate with respect to the bed body by transferring the intermediate member in the body axial direction with respect to the bed body or the top plate. The control means corrects the position of the top plate transferred by the top plate transfer means by controlling the intermediate transfer means.

Description

  Embodiments described herein relate generally to a medical bed apparatus and an X-ray CT apparatus.

  A medical couch device used in an X-ray CT apparatus includes a couch body, a couchtop on which a subject is placed, and couchtop moving means for moving the couchtop in the body axis direction of the couch body. It has (for example, patent document 1).

  The X-ray CT apparatus has a gantry equipped with X-ray imaging means that rotates around the body axis of the subject. While moving the subject on the top plate along the body axis, rotate the X-ray imaging means around the body axis, and based on the X-rays irradiated from the X-ray imaging means and transmitted through the subject Image data of the tomographic image (hereinafter simply referred to as data) is acquired. In order to image a wide range of the subject in a short time, the speed of moving the top plate is increased. When the top plate is stopped urgently, safety is ensured by stopping the top plate within a predetermined distance.

  As an example of CT imaging, X-ray is performed while reciprocating a subject on the top plate from the outside to the inside (IN direction) and from the inside to the outside (OUT direction) along the body axis. There is a shuttle scan to shoot. Here, the position of the top plate at the start of CT imaging in the IN direction is referred to as the start, the position of the top plate at the end of CT imaging is referred to as the end, and the position of the top plate at the start of CT imaging in the OUT direction May be referred to as the end, and the position of the top plate at the end of CT imaging may be referred to as the start.

  Based on the difference image between the data acquired when the top plate is moved to a predetermined position through the shuttle scan and the data acquired when the top plate is moved again to the predetermined position after that, time series It becomes possible to observe the change of. In order to obtain an accurate difference image, it is necessary to match the trajectory of the X-ray source when the top plate is moved from the start end to the end and then the top plate is moved again from the start end to the end. In order to match the trajectory of the X-ray source in both movements, alignment of the top ends of the top plates, alignment of the end points, and speed adjustment of the top plate when moving between the start and end points Is important (highly accurate position repeatability).

Japanese Patent Laid-Open No. 08-98832

  However, in the conventional medical couch device, the inertial force of the top plate and the subject increases as the top plate moves, so that when the top plate is urgently stopped, the top plate is stopped after being braked. It becomes difficult to stop the top plate within a predetermined distance, and it is difficult to ensure safety.

  In addition, with conventional shuttle scans, the inertial force of the top plate and the subject increases as the speed of the top plate moves. There was a problem that it was difficult to reproduce with high accuracy.

  This embodiment solves the above-described problem, provides a medical bed apparatus capable of ensuring safety, and X-ray CT capable of reproducing the position of the top plate with high accuracy. An object is to provide an apparatus.

In order to solve the above-described problems, a medical bed apparatus according to an embodiment includes a bed body, a top plate, a top plate moving unit, an intermediate member, an intermediate moving unit, and a control unit. A subject is placed on the top board. The top plate moving means reciprocates the top plate with respect to the bed body along the body axis direction. The intermediate member is disposed between the bed body and the top plate so as to be movable along the body axis direction of the subject. The intermediate moving means moves the top plate relative to the bed main body by moving the intermediate member along the body axis direction with respect to the bed main body or the top plate. The control unit corrects the position of the top plate moved by the top plate moving unit by controlling the intermediate moving unit.
In addition, the X-ray CT apparatus of the embodiment includes a bed body, a top plate, X-ray imaging means, a top plate moving means, an intermediate moving means, and a control means. The X-ray imaging unit images the subject placed on the top board with X-rays. The top plate moving means reciprocates the top plate in the body axis direction with respect to the bed main body. The intermediate member is disposed between the bed body and the top plate so as to be movable along the body axis direction of the subject. The intermediate moving means moves the top plate relative to the bed main body by moving the intermediate member along the body axis direction with respect to the bed main body or the top plate. The control unit corrects the position of the top plate moved by the top plate moving unit by controlling the intermediate moving unit.

1 is a configuration block diagram of an X-ray CT apparatus according to an embodiment. The fragmentary sectional view of a medical bed apparatus. The block diagram of a control means. The figure which shows the correspondence of the number of drive pulses, and the number of detection pulses. The displacement diagram of a top plate. A speed diagram of the top board. Configuration block diagram of console and the like. The figure of a power sequence circuit. The flowchart which shows a series of operation | movement in a shuttle scan.

[First Embodiment]
Next, an embodiment of an X-ray CT apparatus will be described with reference to the drawings. FIG. 1 is a configuration block diagram of an X-ray CT apparatus, and FIG. 2 is a partial cross-sectional view of a medical bed apparatus. In this embodiment, the horizontal direction orthogonal to the body axis direction of the subject may be referred to as the X direction, the vertical direction orthogonal to the body axis direction may be referred to as the Y direction, and the IN direction / OUT direction may be referred to as the Z direction.

  As shown in FIG. 1, the X-ray CT apparatus has a bed main body 1, a top plate 2, an intermediate member 3, a top plate moving means 4, an intermediate moving means 5, a console 6, and a gantry 7.

(Top plate, intermediate member)
The top 2 is for placing the subject P. An intermediate member 3 is disposed between the bed body 1 and the top plate 2.

  As shown in FIGS. 1 and 2, a top plate guide means 21 is disposed between the top plate 2 and the intermediate member 3. The top plate guide means 21 includes a slider 22 provided on the top plate 2 and a guide rail 23 provided on the intermediate member 3, formed in a long shape, and having the long direction as the Z direction. A slider 22 is fitted to the guide rail 23 so as to be movable in the Z direction. Thereby, the top plate 2 is configured to be guided in the Z direction with respect to the intermediate member 3.

  Intermediate guide means 31 is disposed between the bed main body 1 and the intermediate member 3. The intermediate guide means 31 includes a slider 32 provided on the intermediate member 3, and a guide rail 33 provided on the bed main body 1, formed in an elongated shape, and having the longitudinal direction as the Z direction. A slider 32 is fitted to the guide rail 33 so as to be movable in the Z direction. Thereby, the intermediate member 3 is configured to be guided in the Z direction with respect to the bed main body 1.

The top plate 2 operates as follows by the top plate guide means 21 and the intermediate guide means 31.
When the top plate 2 is moved at the speed V1 with respect to the intermediate member 3, and the intermediate member 3 is moved at the speed V2 with respect to the bed body 1, the speed of the top plate 2 with respect to the bed body 1 is the speed V1 and the speed V2. A value obtained by adding (V1 + V2).

  That is, when the top plate 2 is moved, the speed of the top plate 2 can be corrected by moving the intermediate member 3 in the same direction / different direction as the top plate 2 to accelerate / decelerate the top plate 2. It becomes possible. The speed correction will be described later.

  Further, when the top plate 2 is moved or stopped, the position of the top plate 2 can be corrected by moving the intermediate member 3 in the IN / OUT direction. The position correction will be described later.

(Top plate moving means, top plate control unit)
As shown in FIG. 2, the top plate moving means 4 includes a motor 41, an output gear 42, a pinion 43, and a rack 44. Here, for simplicity of explanation, the output gear 42 and the pinion 43 are directly meshed, but may be indirectly meshed via a reduction gear.

  The control means is configured by any one of the system control unit 61 and the scan control unit 62 or a combination thereof (see FIG. 7). The control means for reciprocating the top board 2 by outputting a control signal to the top board moving means 4 may be referred to as a top board control unit 601 (see FIG. 3).

  As shown in FIG. 2, the motor 41 is provided on the top plate 2. As the motor 41, for example, a stepping motor that rotates by a step angle and stops when one pulse is received is used. Here, this pulse for rotating the motor 41 by the step angle may be referred to as a control signal or a drive pulse. Further, the step angle is set to, for example, 0.9 ° (see FIG. 4). In addition to the drive pulse, the motor 41 is also given a direction instruction signal for controlling the rotation direction. Further, the motor 41 includes a drive circuit that supplies power to the motor 41 based on the drive pulse and the direction instruction signal.

  The output gear 42 is rotated by the motor 41. The pinion 43 is meshed with the output gear 42. The rack 44 is provided on the intermediate member 3. The rack 44 is engaged with the pinion 43. When the motor 41 rotates the output gear 42 forward / reversely, the pinion 43 extends / retracts the rack 44, thereby moving the table 2 in the IN / OUT direction with respect to the bed main body 1 (and the intermediate member 3). Let The configuration including the output gear 42, the pinion 43, and the rack 44 is an example of the power transmission mechanism for the top plate.

  When the motor 41 continuously receives pulses at a constant frequency, the motor 41 rotates at a constant speed. When the motor 41 receives 400 pulses, the motor 41 stops at a position rotated by 400 times the step angle (0.9 ° × 400) (position rotated once). When the control means gives 400 pulses to the motor 41 and rotates once, the output gear 42 and the pinion 43 rotate one time (360 ° rotation), and the rack 44 (top plate 2) moves 40 [mm]. Move in the IN direction / OUT direction (see FIG. 4).

(Rotation amount detector)
FIG. 3 is a block diagram of the control means. As shown in FIG. 3, the control means has a rotation amount detection unit 602. As an example of the rotation amount detection unit 602, there is a rotary encoder that detects the rotation amount of the pinion 43 by counting the number of pulses output every time the pinion 43 is rotated by a predetermined angle (for example, 4.5 °). Yes (see FIG. 4). Note that a pulse for detecting the rotation amount of the pinion 43 may be referred to as a detection pulse.

  When the rotation amount detection unit 602 counts one detection pulse, the pinion 43 should be rotated by 4.5 ° (= 360 ° / 80) degrees, so the top plate 2 is set to 0.5 (= 40 / 80) It is detected that [mm] has been moved.

  That is, the detection result (number of detection pulses) detected by the rotation amount detection unit 602 corresponds to the amount of movement of the table 2 moved by the table moving means 4. By adding this detection result to the position, the actual position of the top board after movement can be obtained. The rotation amount detection unit 602 is an example of a position detection unit that detects the position of the top 2 based on the rotation amount of the pinion 43.

  Further, since the number of detection pulses output in a certain time corresponds to the moving speed of the top plate 2, the top plate 2 is moved if the number of detection pulses output per second is counted. Speed [mm / s] can be obtained. That is, the moving speed of the top 2 can be obtained using the rotation amount detection unit 602. At this time, the rotation amount detection unit 602 corresponds to an example of a speed detection unit.

(Correspondence between the number of drive pulses and the number of detection pulses)
Next, the correspondence between the number of drive pulses, which is a control signal sent from the control means to the motor 41, and the number of detection pulses detected by the rotation amount detection unit 602 will be described with reference to FIG. FIG. 4 is a diagram illustrating a correspondence relationship between the number of drive pulses and the number of detection pulses.

  As shown in FIG. 4, in order to move the top 2 by 40 [mm] by the control means, 400 drive pulses may be transmitted from the control means to the motor 41. On the other hand, when the top plate 2 is moved by 40 [mm], the rotation amount detection unit 602 should count 80 detection pulses. That is, the correspondence between the number of drive pulses and the number of detection pulses is a relationship of 400 to 80 (5 to 1). If this correspondence is established, it can be seen that the detected actual position of the top plate 2 matches the position of the top plate 2 based on the control signal from the control means. In addition, the position of the top plate 2 based on the control signal may be referred to as a planned position.

  However, when this correspondence (5 to 1) is not established, the actual position of the top plate 2 does not match the planned position due to some cause (for example, a very large inertia force), and the actual state of the top plate 2 It can be seen that the planned position is deviated from the position.

  For example, when 400 driving pulses (control signal) are sent from the control means to the motor 41 and the top plate 2 is moved based on the control signal, when the rotation amount detection unit 602 counts 82 detection pulses, Since the correspondence is 400 to 82 and the 5 to 1 relationship is not established, it can be seen that the planned position is deviated from the actual position of the top 2. If the planned position is not shifted, the correspondence should be 400 to 80. A difference 2 (= 82-80) in the number of detection pulses at this time corresponds to a difference 1 [mm] between the actual position of the top plate 2 and a planned position. The difference in the number of detection pulses or the difference between the actual position of the top plate 2 and the planned position is the positional deviation amount δ (see FIG. 5).

  FIG. 5 is a displacement diagram of the top plate 2. In FIG. 5, the horizontal axis represents the time axis and the vertical axis represents the displacement. Further, in FIG. 5, a displacement diagram at normal time is shown by a solid line, and a displacement diagram at abnormal time is shown by a broken line. In FIG. 5, the acceleration area | region, the constant speed area | region, and the deceleration area | region of the top plate 2 are shown by time (t0-t1), time (t1-t2), and time (t2-t3). The positions at times t0 and t3 are, for example, the start and end positions in X-ray imaging in the IN direction.

  As shown in FIG. 5, when the acceleration, constant speed, and deceleration of the top plate 2 become abnormal, the actual position of the top plate 2 naturally shifts from the planned position. Therefore, in the shuttle scan, it becomes difficult to align the top plate and adjust the speed.

  FIG. 6 is a velocity diagram of the top plate 2 corresponding to the displacement diagram shown in FIG. In FIG. 6, the horizontal axis represents the time axis and the vertical axis represents the speed.

  When the top plate 2 is accelerated, constant speed, and decelerated, it may become abnormal. One of the causes is that the weight of the subject placed on the top plate 2 greatly exceeds the standard value, or the top plate 2 is moved at a high speed, so that the inertial force becomes very large. It is. In FIG. 6, the speed diagram at normal time is shown by a solid line, and the speed diagram at abnormal time is shown by a broken line.

(Deviation amount calculation unit)
As illustrated in FIG. 3, for example, the shift amount calculation unit 603 includes the number of detection pulses to be counted when the planned position is not shifted from the actual position of the top 2, and the rotation amount detection unit 602. To obtain the difference from the number of detection pulses actually counted.

  The deviation amount calculation unit 603 integrates the positional deviation amount δ when the top 2 is moved from the start end to the end.

  By accumulating the positional deviation amount δ, the positional deviation amount δ can be obtained at an arbitrary position in the moving region between the start end and the end point.

(Intermediate moving means, intermediate control unit)
Even if acceleration, constant speed and deceleration of the top plate 2 become abnormal, an intermediate moving means 5 is provided for aligning the start ends and end ends in the shuttle scan. Note that the control means for correcting the position of the top 2 moved by the top moving means 4 by outputting a control signal to the intermediate moving means 5 may be referred to as an intermediate control unit 604 (see FIG. 3).

  As shown in FIG. 2, the intermediate moving means 5 includes a motor 51, an output gear 52, a pinion 53, and a rack 54. In this embodiment, the intermediate moving means 5 is the same as the configuration of the top board moving means 4, but it is not necessary to be the same, and the step angle of the motor 51 may be changed. Further, the gear ratio of the output gear 52, the pinion 53, and the rack 54 may be changed.

  The motor 51 is provided on the intermediate member 3. As the motor 51, a stepping motor that rotates by a step angle and stops when one pulse is received is used. Here, this pulse for rotating the motor 51 by the step angle may be referred to as a feedback pulse. The step angle is set to 0.9 °, for example. In addition to the feedback pulse, the motor 51 is also provided with a direction instruction signal for controlling the rotation direction. Further, the motor 51 includes a drive circuit that supplies power to the motor 51 based on the feedback pulse and the direction instruction signal.

  The output gear 52 is rotated by the motor 51. The pinion 53 is meshed with the output gear 52. The rack 54 is provided in the bed main body 1. The rack 54 is engaged with the pinion 53. When the motor 51 rotates the output gear 52 forward / reversely, the pinion 53 extends / retracts the rack 54, thereby moving the top 2 (and the intermediate member 3) in the IN / OUT directions with respect to the bed body 1. Let The configuration including the output gear 52, the pinion 53, and the rack 54 is an example of an intermediate power transmission mechanism.

  When the motor 51 continuously receives feedback pulses at a constant frequency, it rotates at a constant speed. When the motor 51 receives 400 feedback pulses, the motor 51 stops at a position rotated by 400 times the step angle (0.9 ° × 400) (position rotated once). When the control means gives 400 feedback pulses to the motor 51 to make one rotation, the control means causes the output gear 52 and the pinion 53 to make one rotation each and causes the rack 54 (intermediate member 3) to move in the 40 [mm] IN direction. Move in the / OUT direction.

(Position correction)
As described above, when the correspondence between the number of drive pulses and the number of detection pulses is not 400 to 80 (5 to 1), the actual position of the top 2 and the expected position did not match. Recognize. In order to match both positions, the intermediate moving means 5 may be moved by the control means.

(Correspondence between the number of feedback pulses and the number of detection pulses)
Next, a correspondence relationship between the number of feedback pulses, which is a control signal sent from the control means to the motor 51, and the number of detection pulses detected by the rotation amount detection unit 602 will be described with reference to FIG. FIG. 4 is a diagram illustrating a correspondence relationship between the number of feedback pulses and the number of detection pulses.

  In this embodiment, the same structure as that of the top plate moving means 4 is used for the intermediate moving means 5 for easy understanding. Therefore, the correspondence between the number of feedback pulses and the number of detection pulses is the same as the correspondence between the number of drive pulses and the number of detection pulses. That is, the relationship is 400 to 80 (5 to 1).

  As an example, when 400 driving pulses (control signals) are sent from the control means to the motor 41, and the top plate 2 is normally moved in the IN direction, for example, based on the control signals, the rotation amount detector 602 has 80 pieces. A case where the number of detection pulses is to be counted and the rotation amount detection unit 602 counts 82 detection pulses will be given. In this case, the deviation amount calculation unit 603 calculates 2 (= 82-80) detection pulses as the positional deviation amount δ. The two detection pulses correspond to 10 feedback pulses.

In this embodiment, it is possible to correct the position of the top plate 2 at an arbitrary position in the moving region between the start end and the end in the shuttle scan, but the positional deviation amount δ is greater than or equal to a threshold value δ ₀ ( When the position is abnormal), the position of the top 2 is corrected.
A positional deviation amount δ ₀ corresponding to one detection pulse is set as a threshold value. Control means, when the position shift amount [delta] is a threshold [delta] ₀ or more (position error), and controls the intermediate moving means 5, to correct the position of the top plate 2.

  When there are two detection pulses as the positional deviation amount δ, the control means sends ten feedback pulses to the motor 51 to move the rack 54 (intermediate member 3) in the 1 [mm] OUT direction. Thereby, it is possible to correct the position of the top board 2 by matching the actual position of the top board 2 with the planned position.

  As described above, when the top plate 2 is moved at a high speed, for example, the inertial force is large. Therefore, even if it becomes difficult to stop the top plate 2 at the predetermined start and end positions, the control is performed. Since the means controls the intermediate moving means 5 and corrects the top plate 2 to a predetermined starting position or the like, the alignment of the top plate 2 is facilitated.

(Speed correction)
As described above, by using the intermediate moving means 5 and the rotation amount detection unit 602, it is possible to correct the position of the top board 2 (correction of positional deviation). It is also possible to correct the movement speed (speed difference correction). Here, the rotation amount detection unit 602 is an example of a speed detection unit.

  The rotation amount detection unit 602 counts the number of detection pulses output in a certain time. The number of detection pulses output in a certain time corresponds to the actual moving speed of the top 2.

  The speed detector obtains the actual moving speed [mm / s] of the top 2 based on the number of detection pulses output per second.

  The motor 41 is configured to rotate at a constant speed when receiving drive pulses at a constant frequency continuously. Therefore, the speed difference detection unit obtains the speed [mm / s] of the top 2 based on the frequency of the drive pulse.

Further, the speed difference calculation unit 605 obtains a difference γ between the actual speed of the top board 2 and the speed of the top board 2 based on the frequency of the driving pulse (see FIG. 6). The intermediate control unit 604 corrects the actual speed of the top 2 to the speed of the top 2 based on the frequency of the drive pulse by controlling the intermediate moving means 5 based on the obtained speed difference γ. .
As an example, when the control means sends a drive pulse with a constant frequency of 1000 [Hz] to the motor 41 and the top plate 2 is normally moved in the IN direction, for example, the rotation amount detection unit 602 is 200 (= 1000/1000 / sec). 5) A case where the rotation amount detection unit 602 counts 202 detection pulses when the number of detection pulses is to be counted will be described. In this case, the speed difference calculation unit 605 calculates 2 (= 202−200) pulses as the speed difference γ in one second of detection pulses. The two detection pulses correspond to a speed of 10 feedback pulses per second and 1 [mm / s].

A speed difference γ ₀ corresponding to one detection pulse is used as a threshold value. When the speed difference γ becomes equal to or greater than the threshold value γ ₀ (speed abnormality), the control means controls the intermediate moving means 5 to correct the moving speed of the top 2.

  When there are two detection pulses as the speed difference γ, the control means sends a feedback pulse with a frequency of 10 [Hz] (10 pulses per second) to the motor 51, and causes the rack 54 (intermediate member 3) to move at a speed of 1 [ mm / s] to move in the OUT direction. Thereby, it becomes possible to correct the speed of the top 2 by matching the actual speed of the top 2 with the planned speed.

  As described above, when the top plate 2 is moved at a high speed, for example, since the inertial force is large, if the moving speed becomes abnormal, the intermediate control unit 604 corrects the normal speed, so that the speed adjustment becomes easy. As a result, it becomes easy to stop the top plate 2 at a predetermined start or end position.

(console)
Next, the console 6 will be described with reference to FIGS. FIG. 7 is a configuration block diagram of a console or the like. Depending on the mounting convenience of the apparatus, it may be mounted inside the gantry or bed, or may be mounted outside them.

  The console 6 includes a system control unit 61, a scan control unit 62, a storage unit 63, a table 64, an image reconstruction processing unit 65, and an interface 66. The interface 66 includes a display unit 67, an input unit 68, and a display control unit 69.

  A control unit is configured by any one of the system control unit 61 and the scan control unit 62 or a combination thereof. The control means includes a top board control unit 601, a deviation amount calculation unit 603, an intermediate control unit 604, and a speed difference calculation unit 605 (see FIG. 3).

  The storage unit 63 stores in advance the time required for reciprocating the top 2, the turning cycle of the X-ray irradiation unit 81, and a plurality of scan ranges.

  In addition, the table 64 stores acceleration time, constant speed time, deceleration time, and the like corresponding to the scan range.

  The control means obtains acceleration time, constant speed time, and deceleration time using the table 64 based on the scan range. Based on the obtained times, the control means includes a top plate moving means 4, a turning movement means 71, an X-ray control device 72, a high voltage generation device 73, an X-ray irradiation unit 81, an X-ray detector 83, a rotation mechanism. 85 and the data collection unit 87 are controlled.

  The top plate moving means 4 receives a control signal from the top plate control unit 601, and moves the top plate 2 along a body axis direction of the subject P from a predetermined start end to a predetermined end. , Reciprocate in the direction from the end to the start.

  The turning movement means 71 receives the control signal from the system control unit 61 and rotates the rotation mechanism 85.

  The X-ray controller 72 controls the timing of high voltage generation by the high voltage generator 73 based on the X-ray beam generation control signal output from the system controller 61. The high voltage generator 73 supplies a high voltage for exposing the X-ray beam to the X-ray irradiation unit 81 in accordance with a control signal from the X-ray controller 72.

  The X-ray irradiation unit 81 emits a fan-shaped X-ray beam having a thickness in the slicing direction toward the subject P from multiple directions by the high voltage supplied from the high voltage generator 73. The X-ray detector 83 detects an X-ray beam that is irradiated from the X-ray irradiation unit 81 and transmitted through the subject P.

  The X-ray detector 83 is composed of a two-dimensional X-ray detector having a multi-channel detection element and arranged in the slice direction. For each row, for example, detection elements of about 1,000 channels are arranged in an arc shape with the focus of the X-ray irradiation unit 81 as the center.

  The rotation mechanism 85 holds the X-ray irradiation unit 81 and the X-ray detector 83 so as to be rotatable about the body axis of the subject P.

  The data collection unit 87 collects and outputs projection data of a plurality of slices of the subject P based on the data collection control signal output from the system control unit 61.

  The image reconstruction processing unit 65 simultaneously reconstructs a plurality of tomographic images of the subject P based on the projection data of the plurality of slices of the subject P collected by the data collecting unit 87. The display control unit 69 causes the display unit 67 to display a plurality of tomographic images of the reconstructed subject P.

  The interface 66 includes a display unit 67, an input unit 68, and a display control unit 69 that controls the display unit 67.

  The input unit 68 is a mouse, a keyboard, or the like, and inputs various information.

  The display control unit 69 causes the display unit 67 to display a plurality of scan ranges stored in the storage unit 63 so as to be selectable.

(Power sequence circuit)
Next, the power sequence circuit will be described with reference to FIG. FIG. 8 is a diagram of a power sequence circuit.

  As shown in FIG. 8, a power sequence circuit for controlling the power supplied to the motors 41, 51 and the like is provided. The power sequence circuit includes a relay, a capacitor 55, a b contact 56, and an a contact 57. Furthermore, an operation switch 681 for cutting off the power supplied to the motor 41 is provided. Note that the operation switch 681 may be referred to as an emergency stop switch.

  In the shuttle scan, the top board control unit 601 controls the top board moving means 4 to move the top board 2 from the predetermined start end to the predetermined end along the body axis direction of the subject P. And reciprocating in the direction from the end to the start. When the motor 41 is decelerated, the electric power converted from the kinetic energy of the motor 41 is stored in the capacitor 55.

When the operation switch 681 is operated while the top plate 2 is moved by the top plate moving means 4, the relay of the power sequence circuit is operated to open the b contact 56 and close the a contact 57.
When the b-contact 56 is opened, the power supplied to the motor 41 is cut off, the top plate 2 is braked by the holding force of the motor 41, and the top plate 2 is stopped.

  When the top plate 2 is moved at high speed, since the inertial force of the top plate 2 and the like is large, the braking distance from when the top plate 2 is braked until the top plate 2 is stopped becomes long. 2 may not be stopped within a predetermined distance.

  Further, by operating the operation switch 681, when the a contact 57 is closed, power is supplied from the capacitor 55 to the motor 51. The intermediate control unit 604 controls the intermediate moving unit 5 to move the intermediate member 3 in the direction opposite to the moving direction of the top plate 2. Thereby, the braking distance is shortened, and the top plate 2 can be stopped within a predetermined distance.

  As described above, by using the intermediate moving means 5 and the intermediate control unit 604, the top plate 2 can be stopped within a safe stop distance during an emergency stop.

  Next, a series of operations in the shuttle scan will be described with reference to FIG. FIG. 9 is a flowchart showing a series of operations in shuttle scan. In a shuttle scan in which the top 2 is scanned while reciprocating between the start and end in the body axis direction (Z direction) of the subject P, the speed difference γ or the positional deviation amount δ is set at predetermined intervals. The speed and position may be corrected by determining whether or not the speed and position are abnormal based on the obtained speed difference γ or positional deviation amount δ. In the following, a series of operations for determining whether the speed is abnormal based on the speed difference γ obtained every predetermined time in the shuttle scan and correcting the speed will be described.

  As shown in FIG. 9, first, the intermediate control unit 604 reads out the obtained speed difference γ (S101).

Next, the intermediate control unit 604 determines whether or not the speed difference γ is greater than or equal to a threshold value γ ₀ (speed abnormality) (S102).

When the intermediate control unit 604 determines that the speed difference γ is not greater than or equal to the threshold value γ ₀ (speed abnormality) (S102: No), the intermediate control unit 604 determines whether the shuttle scan has ended (S103). ).
When the intermediate control unit 604 determines that the shuttle scan is not completed (S103: No), the process returns to step S101 for reading the obtained speed difference γ.

  When the intermediate control unit 604 determines that the shuttle scan is finished (S103: Yes), the process is finished.

In step S102 the difference in speed gamma is to determine whether the threshold gamma ₀ or more (speed error) is intermediate control unit 604, a difference in speed gamma is the threshold value gamma ₀ or more (speed error) Intermediate When the control unit 604 determines (S102: Yes), the intermediate control unit 604 controls the intermediate moving unit 5 to correct the speed of the top 2 (S104). Thereafter, the process proceeds to step S103 for determining whether or not the shuttle scan is completed.

  As described above, in the shuttle scan, when the top plate 2 is reciprocated between a predetermined start end and end, it is determined whether the speed and position are abnormal every predetermined time, and at a high speed. If it is determined that the inertial force has increased and the speed or position has become abnormal, the speed and position are immediately corrected, so that the speed of the top 2 can be easily adjusted and the start and end positions can be aligned. It becomes easy.

  In the above-described embodiment, the speed and position are corrected in the entire area between the start and end in the shuttle scan. However, depending on the types of the acceleration area, the constant speed area, and the deceleration area, the speed is changed. Alternatively, the position correction may be selectively performed.

In the embodiment, when the top plate 2 is moved by the top plate moving means 4, if the obtained speed difference γ is greater than or equal to a predetermined threshold value γ ₀ , the intermediate control unit 604 performs the actual control. Although what has corrected the moving speed to the moving speed based on the control signal has been shown, the present invention is not limited to this. That is, when the top plate 2 is moved by the top plate moving means 4, if the obtained positional deviation amount δ is greater than or equal to a predetermined threshold value δ ₀ , the intermediate control unit 604 causes the top plate 2 to move. The actual position may be corrected to a position based on the control signal.

  Moreover, as shown in FIG. 2, since the basic structure of the top-plate moving means 4 and the intermediate | middle moving means 5 is the same, the reverse aspect may be sufficient. That is, when the top plate 2 is moved by the intermediate moving means 5, the top plate control unit 601 may correct the actual speed and position of the top plate 2 to the speed and position based on the control signal.

  Although several embodiments of the present invention have been described, these embodiments are presented by way of example and are not intended to limit the scope of the invention. These novel embodiments can be implemented in various other forms, and various omissions, rewrites, and changes can be made without departing from the scope of the invention. These embodiments and modifications thereof are included in the scope and gist of the invention, and are included in the invention described in the claims and the equivalents thereof.

DESCRIPTION OF SYMBOLS 1 Bed main body 2 Top plate 21 Top plate guide means 22 Slider 23 Guide rail 3 Intermediate member 31 Intermediate guide means 32 Slider 33 Guide rail 4 Top plate moving means 41 Motor 42 Output gear 43 Pinion 44 Rack 5 Intermediate movement means 51 Motor 52 Output Gear 53 Pinion 54 Rack 55 Capacitor 56 b contact 57 a contact 6 Console 61 System control unit 62 Scan control unit 63 Storage unit 64 Table 65 Image reconstruction processing unit 66 Interface 67 Display unit 68 Input unit 681 Operation switch 69 Display control unit 601 Top plate control unit 602 Rotation amount detection unit 603 Deviation amount calculation unit 604 Intermediate control unit 605 Speed difference calculation unit 7 Base 71 Rotating movement means 72 X-ray control device 73 High voltage generator 81 X-ray irradiation unit 83 X-ray detector 85 Rotating machine 87 data collection unit

Claims (10)

The bed body,
A top plate on which the subject is placed;
A top plate moving means for reciprocating the top plate with respect to the bed body along the body axis direction;
An intermediate member disposed between the bed body and the top plate so as to be movable along the body axis direction of the subject;
Intermediate moving means for moving the top plate relative to the bed main body by moving the intermediate member along the body axis direction with respect to the bed main body or the top plate;
Control means for correcting the position of the top plate moved by the top plate moving means by controlling the intermediate movement means;
Having
A medical couch device characterized by. A bed body, a top plate, and an X-ray imaging unit that images the subject placed on the top plate by X-rays, while rotating the X-ray imaging unit around the body axis of the subject, In the X-ray CT apparatus for reciprocating the top plate along the body axis direction of the subject,
A top plate moving means for reciprocating the top plate in the body axis direction with respect to the bed body;
An intermediate member disposed between the bed body and the top plate so as to be movable along the body axis direction of the subject;
Intermediate moving means for moving the top plate relative to the bed main body by moving the intermediate member along the body axis direction with respect to the bed main body or the top plate;
Control means for correcting the position of the top plate moved by the top plate moving means by controlling the intermediate movement means;
Having
X-ray CT apparatus characterized by this. The control means includes
When the intermediate member is in a predetermined position with respect to the bed main body, a top board control unit that moves the top board relative to the bed main body by outputting a control signal to the top board moving means;
A position detector that detects the position of the top plate moved by the top plate moving means;
A displacement amount calculation unit for obtaining a displacement amount that is a difference between the detected actual position of the top plate and the position of the top plate based on a control signal;
Based on the obtained positional deviation amount, the intermediate movement means is controlled to move the intermediate member to the predetermined position with respect to the bed body, whereby the actual position of the top plate is based on the control signal. An intermediate control unit for correcting the position;
Having
The X-ray CT apparatus according to claim 2. The intermediate control unit corrects the actual position of the top plate to a position based on a control signal when the obtained positional deviation amount is larger than a predetermined threshold value.
The X-ray CT apparatus according to claim 3. The deviation amount calculation unit obtains a positional deviation amount at a starting end that is a position of the top plate when imaging by X-rays is started and an end that is a position of the top plate when imaging by X-rays is started. ,
The X-ray CT apparatus according to claim 3. The deviation amount calculation unit integrates the positional deviation amount when the top plate is moved from the start end to the end, and the positional deviation amount when the top plate is moved from the end end to the start end,
The X-ray CT apparatus according to claim 5. The control means includes
A top plate control unit for moving the top plate relative to the bed body by outputting a control signal to the top plate moving means;
A speed detector for detecting a moving speed of the top plate moved by the top plate moving means;
A speed difference calculating unit for obtaining a speed difference which is a difference between the detected actual moving speed of the top plate and a moving speed of the top plate based on a control signal;
The intermediate movement means is controlled based on the obtained speed difference, and the intermediate member is moved relative to the bed main body, so that the actual movement speed of the top plate is changed to a movement speed based on a control signal. An intermediate control unit to correct,
Having
The X-ray CT apparatus according to claim 2. The intermediate control unit corrects the actual moving speed to a moving speed based on a control signal when the obtained speed difference is larger than a predetermined threshold;
The X-ray CT apparatus according to claim 7. The intermediate moving means is
A motor provided on one of the intermediate member and the bed body;
An intermediate power transmission mechanism that is provided on the other of the intermediate member and the bed body, receives the power of the motor, and moves the intermediate member in a direction parallel to the bed body;
Having
An X-ray CT apparatus according to claim 2, wherein: The top plate moving means includes:
A motor provided on one of the intermediate member and the top plate;
A power transmission mechanism for a top plate that is provided on the other of the intermediate member and the top plate, receives the power of the motor, and moves the intermediate member in a direction parallel to the top plate;
Having
The X-ray CT apparatus according to claim 9.

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