JP2009247391A - Medical image diagnosis apparatus - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To detect movement of the position of a cradle in the vertical direction. <P>SOLUTION: An X-ray CT apparatus 1 comprises: a positioning light 107 for irradiating the rear surface 202a of the cradle 202 fed out from a support table 201 with light; a light receiving part 204 for receiving the reflection light from a specific reflection position on the rear surface 202a of the cradle 202; and a movement detection part 1103 for detecting the movement of the cradle in the vertical direction based on the state of the received reflection light in the light receiving part 204. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a medical image diagnostic apparatus that captures a medical image of a subject.

  As a medical image diagnostic apparatus that captures a medical image of a subject, for example, an X-ray CT (Computed Tomography) apparatus, an MRI (Magnetic Resonance Imaging) apparatus, and the like are known (for example, see Patent Document 1).

The X-ray CT apparatus and the MRI apparatus include a gantry for imaging a subject and a table for transporting the subject to an imaging space of the gantry. The table includes a support base and a cradle provided on the support base so as to be movable in the horizontal direction, and the cradle carrying the subject is unwound from the support base to transport the subject to the imaging space. ing.
JP 2007-325853 A

  The imaging of the subject in the imaging space may be performed by moving the cradle in a direction in which the cradle is drawn out from a support base, or may be performed by moving the cradle in a direction in which the cradle is retracted into the support base. In any case, the larger the amount of the cradle that is fed from the support base, the more the bending moment acting on the cradle increases due to the combined weight of the cradle and the weight of the subject. On the contrary, the smaller the amount of feeding, the smaller the amount of downward bending. Accordingly, when imaging is performed by moving the cradle in the direction of feeding out from the support base, the position of the subject on the scan surface gradually moves downward. In addition, when imaging is performed by moving the cradle in the direction in which the cradle is retracted to the support base, the position of the subject on the scan surface gradually moves upward. As described above, when the position of the subject on the scan plane moves in the vertical direction, the obtained image may protrude from the display screen, and when a three-dimensional image is created based on the tomographic image, An accurate image cannot be obtained. Furthermore, there is a risk of hindrance when performing radiation therapy or the like based on the obtained image.

  Further, since the moment acting on the cradle varies depending on the amount of the cradle that is fed from the support base, if the driving force of the motor that moves the cradle in the horizontal direction is constant, the acceleration of the cradle is This differs depending on the amount of the cradle that is fed from the support base.

  The problem to be solved by the present invention is to detect that the position of the cradle has moved up and down.

  Another problem to be solved by the present invention is to correct the vertical movement even if the position of the cradle moves in the vertical direction.

  Furthermore, another problem to be solved by the present invention is to keep the acceleration of the cradle moving in the horizontal direction in a state where the cradle is extended from the support base.

  The present invention has been made in order to solve the above-mentioned problems. The invention of the first aspect is provided with an imaging unit for imaging a subject, a support base, and a horizontally movable on the support base. And a table having a cradle for transporting the subject to the imaging unit, and moving the cradle in the horizontal direction in order to feed the cradle from the support base or to retract the cradle fed from the support base A horizontal movement control unit for controlling the cradle, a light emitting unit for irradiating light to the back surface of the cradle fed out from the support, and a specific reflection position on the back surface of the cradle. A light receiving unit that receives the reflected light, and a movement detection unit that detects the movement of the cradle in the vertical direction based on the light receiving state of the reflected light in the light receiving unit. A medical image diagnostic apparatus according to claim Rukoto.

The invention of the second aspect is characterized in that, in the invention of the first aspect, there are a plurality of the light receiving parts, and each light receiving part is arranged so as to receive reflected light from different reflection positions in the vertical direction. And a medical image diagnostic apparatus.

  A third aspect of the invention is the medical image diagnostic apparatus according to the second aspect of the invention, further comprising correction means for correcting movement of the cradle in the vertical direction based on detection by the movement detection unit. It is.

  According to a fourth aspect of the present invention, in the third aspect of the invention, when a light receiving unit that receives reflected light among the plurality of light receiving units is changed, the vertical position on the scan surface of the cradle is at the start of imaging. The medical image diagnostic apparatus includes a vertical movement control unit that controls the vertical movement of the cradle as the correction unit so as to return to the position.

  According to a fifth aspect of the invention, in the fourth aspect of the invention, in the case where photographing is performed by the photographing unit while moving the cradle in a direction in which the cradle is extended from the support base, a light receiving unit that receives reflected light is more When the light receiving unit changes to a light receiving unit that receives reflected light from a lower reflection position, the vertical movement control unit moves the cradle upward to return to the position at the start of photographing, while the cradle is moved to the support base. When performing imaging by the imaging unit while moving in the retracting direction, when the light receiving unit that receives reflected light is changed to a light receiving unit that receives reflected light from a higher reflection position, the vertical movement control unit Is a medical image diagnostic apparatus characterized in that the cradle is moved downward so as to return to the position at the start of imaging.

  A sixth aspect of the invention is the medical image diagnostic apparatus according to the third aspect of the invention, wherein the correction means corrects a display position of the obtained image.

  A seventh aspect of the invention is the medical image diagnostic apparatus according to any one of the first to sixth aspects, wherein the light reflection position on the back surface of the cradle is on the scan plane.

  The invention of an eighth aspect is the invention of any one of the first to seventh aspects, wherein the light emitting part is provided in the photographing part, and the light receiving part is provided on a feeding side of the cradle in the support base. A medical image diagnostic apparatus characterized by comprising:

  A ninth aspect of the invention is the medical image diagnostic apparatus according to any one of the first to seventh aspects, wherein the light emitting unit and the light receiving unit are provided in the imaging unit. .

  According to a tenth aspect of the present invention, in the eighth or ninth aspect of the invention, the light emitting unit provided in the imaging unit irradiates the subject on the cradle conveyed to the imaging unit with visible light. A medical image diagnostic apparatus characterized by being a positioning light for positioning a specimen.

  An eleventh aspect of the invention is the invention according to any one of the first to seventh aspects, wherein the light emitting part and the light receiving part are provided on a feeding side of the cradle in the support base. This is a medical image diagnostic apparatus.

  The invention according to a twelfth aspect is the invention according to any one of the first to eleventh aspects, wherein the horizontal movement control unit has a constant acceleration of the cradle that moves in the horizontal direction based on detection by the movement detection unit. Thus, the medical image diagnostic apparatus is characterized in that the driving force of the cradle is controlled.

  According to the first aspect of the invention, the reflection position of the light on the back surface of the cradle is different in the vertical direction according to the amount of deflection that varies depending on the amount of extension of the cradle from the support base. Since only the reflected light from the specific reflection position is received and the reflected light from the other reflection positions is not received, the light receiving state of the reflected light at the light receiving portion, that is, the reflected light is not received. When the movement detecting unit detects that the cradle is ready to be received and the reflected light is not received, the position of the cradle is set in the vertical direction compared to the time when the photographing is started. The movement can be detected.

  According to the second aspect of the invention, since each of the light receiving units receives reflected light from different reflection positions in the vertical direction, the amount of movement of the cradle in the vertical direction can be detected.

  According to the third aspect, the movement of the cradle in the vertical direction can be corrected by the correction means.

  According to the fourth aspect of the invention, the movement in the vertical direction is corrected even if the position on the scan plane moves in the vertical direction compared to the time when the imaging is started due to the movement of the deflection amount of the cradle. The position of the cradle can be kept at the position at the start of shooting.

  According to the fifth aspect of the invention, even when the cradle moves downward from the start of photographing, the up-and-down movement control unit is configured to perform photographing while moving the cradle in the direction of feeding out from the support base. Even if the cradle moves upward from the start of photographing by moving the cradle upward and, on the other hand, moving the cradle in the direction in which the cradle is retracted into the support base, the vertical movement control unit Since the cradle is moved downward, the position of the cradle can be maintained at the position at the start of photographing.

  According to the sixth aspect of the invention, the display position of the obtained image can be corrected as correction of the movement of the cradle in the vertical direction.

  According to the seventh aspect of the invention, it is possible to detect the movement of the cradle in the vertical direction on the scan plane.

  According to the eighth aspect of the invention, the light from the light emitting unit provided in the photographing unit is irradiated on the back surface of the cradle, and the reflected light from a predetermined reflection position is on the feeding side of the cradle in the support base. The light is received by the light receiving unit provided in the.

  According to the ninth aspect of the invention, light from the light emitting unit provided in the photographing unit is irradiated on the back surface of the cradle, and reflected light from a predetermined reflection position is provided in the light receiving unit provided in the photographing unit. Is received.

  According to the tenth aspect of the present invention, it is possible to detect that the position of the cradle has moved up and down as compared to the time of starting photographing using an existing positioning light.

  According to the eleventh aspect of the invention, light from the light emitting portion provided on the cradle feed-out side of the support table is irradiated to the back surface of the cradle, and reflected light from a predetermined reflection position is reflected on the support table. The light is received by the light receiving unit provided in the.

  According to the twelfth aspect of the invention, the acceleration of the cradle that moves in the horizontal direction while being drawn out from the support base can be made constant.

Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.
(First embodiment)
First, the first embodiment will be described. FIG. 1 is a block diagram showing a schematic configuration of a first embodiment of an X-ray CT apparatus which is an embodiment of a medical image diagnostic apparatus according to the present invention. FIG. 2 shows a gantry and an X-ray CT apparatus shown in FIG. FIG. 3 and FIG. 4 are diagrams showing the position of the cradle at the time of scanning.

  As shown in FIG. 1, the X-ray CT apparatus 1 is configured to include a gantry 100, a table 200, and an operation console 300.

  The gantry 100 is an example of an embodiment of an imaging unit in the present invention, and includes a donut-shaped rotating body 102 having a cavity 101 as an imaging space. In the rotating body 102, an X-ray tube 103 that generates X-rays and a collimator 104 that defines an irradiation range of the X-rays from the X-ray tube 103 are provided. In the rotating body 102, an X-ray detector 105 for detecting X-rays irradiated from the X-ray tube 103 and transmitted through the patient, and projection data obtained by the X-ray detector 105 are collected. A data collection unit 106 is provided. The X-ray tube 103 and the collimator 104, the X-ray detection unit 105, and the data collection unit 106 are provided at positions facing each other with the cavity 101 interposed therebetween, and the relationship is maintained in a state where the relationship is maintained. The rotating body 102 rotates.

  The rotating body 102 is provided with a positioning light 107 that irradiates the subject conveyed to the cavity 101 by a cradle 202 (to be described later) of the table 200 with visible light for positioning the subject before scanning. Is provided. From this positioning light 107, the light beam of the laser beam that spreads in a fan shape in the X-axis direction, that is, in the direction orthogonal to the body axis direction of the subject conveyed into the cavity 101 by the cradle 202 is the cavity 101. The cradle 202 is irradiated. The laser beam emitted from the positioning light 107 coincides with the scan plane. Further, the laser beam emitted from the positioning light 107 is projected as a linear light beam extending in the X-axis direction onto the cradle 202 or the subject on the cradle 202. The positioning light 107 can irradiate the back surface 202a of the cradle 202 with laser light during scanning by rotating the rotating body 102. The positioning light 107 is an example of an embodiment of a light emitting unit in the present invention.

  The gantry 100 includes an X-ray tube controller 108 that controls the X-ray tube 103 and a rotating body controller 109 that controls the rotation of the rotating body 102. A control signal is output from the main controller 110 to the X-ray tube controller 108 and the rotating body controller 109. The main controller 110 outputs a control signal to each part of the gantry 100 in addition to the X-ray tube controller 108 and the rotating body controller 109 so that imaging (scanning) is performed under predetermined imaging conditions. ing. Further, the main controller 110 controls the turning on and off of the positioning light 107.

  The main controller 110 controls the table 200 in addition to the various controls described above. Specifically, the main controller 110 moves the cradle 202 up and down by moving a horizontal movement control unit 1101 for moving the cradle 202 of the table 200 in the horizontal direction and the support base 201 up and down. And a vertical movement control unit 1102 for moving in the direction.

  The horizontal movement control unit 1101 outputs a control signal for moving the cradle 202 in the horizontal direction to the table 200 in response to an input from an operation button (not shown) provided in the operation console 300 or the gantry 100. The vertical movement control unit 1102 sends a control signal for raising / lowering an elevator unit 203 (to be described later) of the table 200 when there is an input from an operation button (not shown) provided on the operation console 300 or the gantry 100. Output to 200.

  Further, the main controller 110 receives a light receiving signal indicating that reflected light is received by the light receiving unit 204 from a light receiving unit 204 (to be described later) of the table 200, and the light receiving state of the reflected light by the light receiving unit 204 is received. Is provided with a movement detection unit 1103 that detects the movement of the cradle 202 in the vertical direction. In this example, the movement detection unit 1103 receives the light reception signal when no light reception signal is input from the light reception unit 204 and when the light reception signal is input from the light reception unit 204. When there is no more input, it is determined that the cradle 202 has moved up and down. The movement detector 1103 detects the movement of the cradle 202 on the scan plane.

  The table 200 includes a support table 201 and a cradle 202 that is provided on the support table 201 so as to be movable in the horizontal direction and conveys a subject to the cavity 101 of the gantry 100. The support table 201 is moved in the vertical direction by the elevating part 203, so that the cradle 202 can be moved in the vertical direction. The operation of the elevating unit 203 is controlled by a control signal from the vertical movement control unit 1102.

  Further, the cradle 202 is moved in the horizontal direction by a motor (not shown) and is drawn out from the support base 201 or retracted from the extended state. The movement of the cradle 202 in the horizontal direction is controlled by a control signal from the horizontal movement control unit 1101.

  The support base 201 is provided with a light receiving portion 204 on the side surface of the cradle 202 on the feeding side. The light receiving unit 204 is for receiving laser light (reflected light) reflected from the positioning light 107 irradiated to the back surface 202a of the cradle 202.

  The light receiving unit 204 is a photodiode, a phototransistor, a CCD image sensor, or the like, and is preferably a light receiving element having a relatively high directivity. Here, the reflection position of the reflected light received by the light receiving unit 204 on the back surface of the cradle 202 will be described. The bending amount of the cradle 202 changes according to the amount of feeding from the support table 201, and the position on the scan surface moves in the vertical direction. Specifically, the amount of bending of the cradle 202 increases as the amount of feeding from the support base 201 increases, and the amount of bending decreases as the amount of feeding decreases. Accordingly, the position of the cradle 202 on the scan surface becomes lower as the feeding amount from the support base 201 becomes larger, and becomes higher as the feeding amount becomes smaller. As described above, the cradle 202 moves in the vertical direction on the scanning surface in accordance with the feed amount from the support table 201, so that the reflection position of the positioning light 107 on the back surface thereof is different from that of the support table 201. The cradle 202 moves in the vertical direction according to the amount of feeding. In this example, as shown in FIG. 2, the light receiving unit 204 has a position A corresponding to the horizontal direction from the light receiving unit 204 as a reflection position on the laser light irradiated from the positioning light 107 (corresponding to a scan surface). The reflected light of the light to be received is received. In other words, the light receiving unit 204 receives a light beam along a straight line connecting the light receiving unit 204 and the position A in FIG.

  A light reception signal indicating that the reflected light is being received by the light receiving unit 204 is output to the movement detection unit 1103 of the main controller 110.

  The operation console 300 includes a central processing unit 301 that controls the entire apparatus, an input device 302 such as a keyboard that receives input from an operator, and a display that displays a tomographic image reconstructed by the central processing unit 301. An apparatus 303 includes a storage device 304 that stores programs, data, data, X-ray tomographic images, and the like.

  Now, an imaging operation in the X-ray CT apparatus 1 will be described. In the X-ray CT apparatus 1, there are a case where scanning is performed by moving the cradle 202 in a direction in which the cradle 202 is extended from the support base 201, and a case where scanning is performed by moving the cradle 202 in a direction in which the cradle 202 is retracted into the support base 201. is there. Hereinafter, each case will be described.

  When scanning is performed by moving the cradle 202 out of the support base 201, as shown in FIG. 3, the cradle 202 is advanced to a scan start position and scanning is started. At this time, the positioning light 107 is positioned below the gantry 100, and the laser light from the positioning light 107 is irradiated onto the back surface 202 a of the cradle 202. Incidentally, whether or not the cradle 202 has reached the scan start position is detected by an encoder (not shown) provided on the table 200. Here, at the start of scanning, the back surface 202a of the cradle 202 does not reach the position A, and the light receiving unit 204 does not receive reflected light. At this time, no light reception signal is input to the movement detection unit 1103 of the main controller 110.

  After the start of scanning, the cradle 202 has a greater amount of deflection as the amount of feed increases, and the position on the scan surface moves downward. As shown in FIG. 4, when the cradle 202 is lowered to the position A, the reflected light is received by the light receiving unit 204. From the light receiving unit 204, a light reception signal indicating a light receiving state is output to the movement detection unit 1103. As a result, the movement detection unit 1103 determines that the cradle 202 has moved up and down as compared to when scanning started.

  On the other hand, when scanning is performed by moving the cradle 202 in the direction in which the cradle 202 is retracted to the support table 201, the scan is started from a state where the cradle 202 is fed from the support table 201 by a predetermined amount. At this time, the laser light from the positioning light 107 is irradiated onto the back surface of the cradle 202. Here, at the start of scanning, as shown in FIG. 4, the back surface of the cradle 202 is at position A, and the reflected light is received by the light receiving unit 204. From the light receiving unit 204, a light reception signal is output to the movement detection unit 1103.

  After the start of scanning, the cradle 202 has a smaller amount of bending as the amount of feeding decreases. Then, when the position of the back surface of the cradle 202 on the scan surface moves upward from the position A as shown in FIG. 3, the reflected light is not received by the light receiving unit 204. At this time, the light receiving signal from the light receiving unit 204 is not input to the movement detecting unit 1103. As a result, the movement detection unit 1103 determines that the cradle 202 has moved up and down as compared to when scanning started.

  According to the X-ray CT apparatus 1 described above, the light receiving unit 204 changes from a state in which reflected light is not received to a light receiving state or from a state in which reflected light is received to a non-light receiving state. When the movement detection unit 1103 detects the time when the cradle 202 is moved, it can be detected that the position of the cradle 202 has moved in the vertical direction compared to the time when the scan was started.

  In addition, since the existing positioning light 107 is used as the light received by the light receiving unit 204 in order to detect the movement of the vertical position of the cradle 202, the addition of a new configuration is minimized. Can do.

  Further, since the laser light from the positioning light 107 is applied to the scan surface, it is possible to detect the vertical movement of the cradle 202 on the scan surface.

  Next, modified examples of the first embodiment will be described with reference to FIGS. FIG. 5 is a front view showing a schematic configuration of a gantry and a table of a modified example of the X-ray CT apparatus of the first embodiment, and FIG. 6 is a reflected light at a light receiving unit in the modified X-ray CT apparatus of the first embodiment. FIG. 7 to FIG. 15 are diagrams for explaining the movement of the cradle during scanning.

  In this modification, a first light receiving portion 204a, a second light receiving portion 204b, and a third light receiving portion 204c are provided as the light receiving portion 204. The reflection positions of the reflected light received by the light receiving portions 204a, 204b, and 204c are different. As a result, the cradle 202 is moved up and down on the scan surface by the distance in the vertical direction between the reflection position of the reflected light received by one light receiving unit and the reflection position of the reflected light received by the other light receiving unit 204. It is possible to detect movement in the direction. This will be specifically described below.

  The first light receiving portion 204a, the second light receiving portion 204b, and the third light receiving portion 204c are provided on the side surface of the cradle 202 on the feeding side so as to be arranged in the vertical direction in this order from above. As shown in FIG. 6, the first light receiving unit 204a receives reflected light with the position A1 as a reflection position, the second light receiving unit 204b receives reflected light with the position A2 as a reflection position, and The third light receiving unit 204c receives reflected light having the position A3 as a reflection position. In other words, the first light receiving unit 204a receives a light beam along a straight line connecting the first light receiving unit 204a and the position A1. The second light receiving unit 204b receives a light beam along a straight line connecting the second light receiving unit 204b and the position A2. Further, the third light receiving unit 204c receives a light beam along a straight line connecting the third light receiving unit 204c and the position A3. Positions A1, A2, and A3 are positions corresponding to the horizontal direction from the respective light receiving portions 204a, 204b, and 204c on the laser light emitted from the positioning light 107, and the position A1 is positioned at the top. Below this position A1 is position A2, and further below this position A2 is position A3.

  Incidentally, the positions A1, A2, and A3 are positions corresponding to the horizontal direction from the respective light receiving portions 204a, 204b, and 204c provided on the support base 201. Therefore, when the support base 201 moves in the vertical direction as will be described later. Although it moves with it, the positional relationship with the cradle 202 is always a fixed positional relationship.

  The distance between the position A1 and the position A2 and the distance between the position A2 and the position A3 are both equal at L1. Therefore, when the reflected light is received by the second light receiving unit 204b from the state where the reflected light is received by the first light receiving unit 204a, compared to when the reflected light is received by the first light receiving unit 204a. Thus, the cradle 202 is lowered downward by L1 on the scanning surface. In addition, when the reflected light is received by the third light receiving unit 204c from the state where the reflected light is received by the second light receiving unit 204b, compared to when the reflected light is received by the second light receiving unit 204b. Thus, the cradle 202 is lowered downward by L1 on the scanning surface. On the contrary, when the reflected light is received by the second light receiving unit 204b from the state where the reflected light is received by the third light receiving unit 204c, compared to when the reflected light is received by the third light receiving unit 204c. Thus, the cradle 202 is moved upward by L1 on the scanning surface. Further, when the reflected light is received by the first light receiving unit 204a from the state in which the reflected light is received by the second light receiving unit 204b, compared to when the reflected light is received by the second light receiving unit 204b. Thus, the cradle 202 is moved upward by L1 on the scanning surface.

  Each of the light receiving units 204a, 204b, and 204c outputs a light reception signal to the movement detection unit 1103 of the main controller 110 when receiving reflected light. The movement detection unit 1103 is in a state where a light reception signal is input from the second light receiving unit 204b from a state where the light reception signal from the first light receiving unit 204a is input, and the second light receiving unit 204b. When the light receiving signal is input from the third light receiving unit 204c, it is determined that the cradle 202 has moved downward by L1 on the scan plane. In addition, the movement detection unit 1103 changes from a state in which a light reception signal from the third light reception unit 204c is input to a state in which a light reception signal is input from the second light reception unit 204b, and the second When the light receiving signal is input from the first light receiving unit 204a from the state in which the light receiving signal from the light receiving unit 204b is input, it is determined that the cradle 202 has moved upward by L1 on the scan plane. .

  When the movement detection unit 1103 determines that the cradle 202 has moved downward by L1 (that is, when the light receiving unit that receives reflected light has changed), the lifting unit 203 moves the support table 201 to L1. The up-and-down movement control unit 1102 outputs a control signal to the table 200 so as to move it upward.

  When the movement detection unit 1103 determines that the cradle 202 has moved upward by L1 (that is, when the light receiving unit that receives reflected light has changed), the lifting unit 203 is moved to the support table 201. The vertical movement unit 1102 outputs a control signal to the table 200 so as to move it downward by L1.

  That is, in this example, the vertical movement control unit 1102 moves the cradle 202 up and down so that the cradle 202 returns to the shooting start position according to the movement amount of the cradle 202 detected by the movement detection unit 1103. The movement in the direction is corrected and is an example of the embodiment of the correction means in the present invention.

  The horizontal movement control unit 1101 is a motor (not shown) that moves the cradle 202 in the horizontal direction so that the acceleration of the cradle 202 moving in the horizontal direction is constant based on the detection in the movement detection unit 1103. To control the driving force. Specifically, when the movement detection unit 1103 determines that the cradle 202 has moved downward by L1, the horizontal movement control unit 1101 makes the acceleration of the cradle 202 moving in the horizontal direction constant. Thus, the driving force of the motor is increased. On the other hand, when the movement detection unit 1103 determines that the cradle 202 has moved upward by L1, the horizontal movement control unit 1101 causes the acceleration of the cradle 202 moving in the horizontal direction to be constant. Reduce the driving force of the motor.

  Now, the imaging operation in the X-ray CT apparatus 1 of this modification will be described. When scanning is performed by moving the cradle 202 out of the support base 201, the cradle 202 is extended out of the support base 201 to a scan start position as shown in FIG. Here, it is assumed that the back surface 202a of the cradle 202 is at the position A1 when the cradle 202 is fed to the scan start position. Accordingly, at the start of scanning, the first light receiving unit 204a is in a light receiving state, and a light receiving signal indicating that the first light receiving unit 204a is in a light receiving state is output to the movement detecting unit 1103 of the main controller 110.

  Then, scanning is started from the state shown in FIG. 7, and when the amount of feeding of the cradle 202 is increased and the back surface 202a of the cradle 202 is lowered to the position A2 as shown in FIG. Receive light. A light reception signal is output to the movement detection unit 1103 from the second light receiving unit 204b. As a result, the movement detection unit 1103 determines that the position of the cradle 202 on the scan surface has been lowered by L1 as compared to the time of starting the scan.

  When the movement detection unit 1103 detects that the position of the cradle 202 on the scan surface has been lowered by L1 as compared to the time of the start of scanning, as shown in FIG. The vertical movement control unit 1102 outputs a control signal to the table 200 so as to move upward by L1. As a result, the position of the cradle 202 on the scan surface returns to the position at the start of scanning.

  Further, when the movement detection unit 1103 detects that the position of the cradle 202 on the scan plane has been lowered by L1 compared to when the scan was started, the horizontal movement control unit 1101 feeds out from the support base 201. The driving force of the motor that moves the cradle 202 in the horizontal direction is increased so that the acceleration of the cradle 202 that moves in the direction becomes constant.

  Further, when the amount of the cradle 202 is increased and the back surface of the cradle 202 is lowered to the position A3 as shown in FIG. 10, the third light receiving portion 204c enters a light receiving state. A light reception signal is output to the movement detection unit 1103 from the third light receiving unit 204c. As a result, the movement detection unit 1103 determines that the position of the cradle 202 on the scan plane is lowered by L1 compared to when the reflected light is received by the second light receiving unit 204b.

  When the movement detection unit 1103 detects that the position of the cradle 202 on the scan surface is lowered by L1 compared to when the reflected light is received by the second light receiving unit 204b, it is shown in FIG. As described above, the vertical movement control unit 1102 outputs a control signal to the table 200 so that the elevating unit 203 moves the support base 201 upward by L1. As a result, the position of the cradle 202 on the scan surface returns to the position at the start of scanning.

  Further, when the movement detection unit 1103 detects that the position of the cradle 202 on the scan plane has dropped by L1 compared to when the reflected light is received by the second light receiving unit 204b, the horizontal movement is performed. The control unit 1101 increases the driving force of the motor that moves the cradle 202 in the horizontal direction so that the acceleration of the cradle 202 that moves in the direction of feeding from the support base 201 is constant.

  On the other hand, when scanning is performed by moving the cradle 202 in the direction in which the cradle 202 is retracted into the support table 201, as shown in FIG. Withdraw gradually. Here, it is assumed that the back surface 202a of the cradle 202 is at the position A3 at the start of scanning. Therefore, at the start of scanning, the third light receiving unit 204c enters a light receiving state, and a light receiving signal indicating that the third light receiving unit 204c is in a light receiving state is output to the movement detecting unit 1103.

  Then, when the feeding amount of the cradle 202 decreases and the back surface 202a of the cradle 202 rises to the position A2, the second light receiving unit 204b enters a light receiving state (see FIG. 8). From the second light receiving unit 204b, a light receiving signal indicating a light receiving state is output to the movement detecting unit 1103. As a result, the movement detection unit 1103 determines that the position of the cradle 202 on the scan surface has increased by L1 as compared to the time of starting the scan.

  When the movement detection unit 1103 detects that the position of the cradle 202 on the scan surface has risen by L1 compared to the time of the start of scanning, as shown in FIG. The vertical movement control unit 1102 outputs a control signal to the table 200 so as to move downward by L1. As a result, the position of the cradle 202 on the scan surface returns to the position at the start of scanning.

  Further, when the movement detection unit 1103 detects that the position of the cradle 202 on the scan plane has risen by L1 as compared to the time of the start of scanning, the horizontal movement control unit 1101 is retracted into the support table 201. The driving force of the motor that moves the cradle 202 in the horizontal direction is reduced so that the acceleration of the cradle 202 that moves in the direction becomes constant.

  Further, when the feeding amount of the cradle 202 is reduced and the back surface of the cradle 202 is raised to the position A1 as shown in FIG. 14, the first light receiving portion 204a is in a light receiving state. From the first light receiving unit 204 a, a light receiving signal indicating that the light is being received is output to the movement detecting unit 1103. Accordingly, the movement detection unit 1103 determines that the position of the cradle 202 on the scan surface has increased by L1 compared to when the reflected light is received by the second light receiving unit 204b.

  When the movement detection unit 1103 detects that the position of the cradle 202 on the scanning surface has increased by L1 compared to when the reflected light is received by the second light receiving unit 204, it is shown in FIG. As described above, the vertical movement control unit 1102 outputs a control signal to the table 200 so that the elevating unit 203 moves the support base 201 downward by L1. As a result, the position of the cradle 202 on the scan surface returns to the position at the start of scanning.

  Further, when the movement detection unit 1103 detects that the position of the cradle 202 on the scan surface has increased by L1 compared to when the reflected light is received by the second light receiving unit 204, the horizontal detection unit 1103 The movement control unit 1101 reduces the driving force of the motor that moves the cradle 202 in the horizontal direction so that the acceleration of the cradle 202 that moves in the direction of retracting into the support table 201 is constant.

  According to the modification of the first embodiment described above, each of the light receiving units 204a, 204b, and 204c receives reflected light from different reflection positions in the vertical direction. The amount of movement of the position in the vertical direction of 202 can be detected.

  Further, even if the cradle 202 moves in the vertical direction compared to the time of the start of scanning due to a change in the amount of deflection from the support base 201, the vertical movement is corrected, and the position on the scan plane is the scan. Return to the starting position. Thereby, the position of the cradle 202 on the scanning surface can be kept at the position at the start of scanning. In this example, the movement of the cradle 202 on the scan plane can be detected, and the cradle 202 is moved based on the movement. Therefore, it is possible to more effectively prevent the obtained tomographic image from being shifted for each scan plane.

  Further, the acceleration of the cradle 202 that moves in the horizontal direction while being drawn out from the support table 201 can be made constant.

(Second embodiment)
Next, a second embodiment will be described. 16 is a block diagram showing a schematic configuration of a second embodiment of the X-ray CT apparatus which is an embodiment of the medical image diagnostic apparatus according to the present invention. FIG. 17 shows a gantry and an X-ray CT apparatus shown in FIG. FIG. 18 to FIG. 20 are diagrams showing the position of the cradle during scanning.

  In the X-ray CT apparatus 10 of this example, the light receiving unit 204 is provided in the gantry 100. In this example, as shown in FIG. 17, the light receiving unit 204 receives reflected light of light having a reflection position at a position B on the laser light emitted from the positioning light 107. In other words, the light receiving unit 204 receives a light beam along a straight line connecting the light receiving unit 204 and the position B in FIG. In this example, the position B is a position where the back surface of the cradle 202 is positioned at the start of scanning.

  In this example, the movement detection unit 1103 detects that the cradle 202 does not receive a light reception signal from a state where the light reception signal is input from the light reception unit 204 when the cradle 202 is at the scan start position. It is determined that it has moved up and down. Incidentally, whether or not the cradle 202 is at the scan position is grasped based on position information of the cradle 202 from the encoder of the table device 200.

  Now, an imaging operation in the X-ray CT apparatus 10 will be described. First, when scanning is performed by moving the cradle 202 in the direction in which the cradle 202 is extended from the support base 201, the scan start position is set when the back surface 202a of the cradle 202 is positioned at the position B. Accordingly, first, as shown in FIG. 18, the cradle 202 is fed out to the scan start position. At this time, the back surface 202 a of the cradle 202 reaches the position B, and the reflected light of the laser light emitted from the positioning light 107 is received by the light receiving unit 204. A light reception signal is output from the light receiving unit 204 to the movement detecting unit 1103 of the main controller 110.

  Then, after the start of scanning, as the amount of feeding of the cradle 202 increases, the position on the scanning surface moves downward, and when the reflected light is not received by the light receiving unit 204 as shown in FIG. No light reception signal is input to the unit 1103. As a result, the movement detection unit 1103 determines that the cradle 202 has moved in the vertical direction as compared to when scanning was started.

  On the other hand, the scanning start position when scanning is performed by moving the cradle 202 in the direction in which the cradle 202 is retracted into the support base 201 is also when the back surface 202a of the cradle 202 is positioned at the position B. Therefore, first, similarly to the above, as shown in FIG. 18, the cradle 202 is brought out to the scan start position. At this time, a light reception signal is output from the light receiving unit 204 to the movement detecting unit 1103.

  Then, after the start of scanning, as the feed amount of the cradle 202 decreases, the position on the scan surface moves upward, and when the reflected light is not received by the light receiving unit 204 as shown in FIG. No light reception signal is input to the unit 1103. As a result, the movement detection unit 1103 determines that the cradle 202 has moved in the vertical direction as compared to when scanning was started.

  Similarly to the first embodiment, the X-ray CT apparatus 10 of the second embodiment can detect that the position of the cradle 202 has moved in the vertical direction as compared to the time of the start of scanning. The light 107 can be used. Furthermore, it is possible to detect the movement of the cradle 202 in the vertical direction on the scan plane.

  Next, a modification of the second embodiment will be described with reference to FIGS. FIG. 21 is a front view showing a schematic configuration of a gantry and a table of a modified example of the X-ray CT apparatus of the second embodiment, and FIG. 22 is a reflected light at the light receiving unit in the modified X-ray CT apparatus of the second embodiment. FIG. 23 to FIG. 31 are diagrams for explaining the movement of the cradle during scanning.

  In this modification, a first light receiving unit 204a, a second light receiving unit 204b, and a third light receiving unit 204c are provided as the light receiving unit 204 provided in the gantry 100. The reflection position of the reflected light received by each of the light receiving portions 204a, 204b, and 204c will be described with reference to FIG. The first light receiving unit 204a receives reflected light with the position B1 as a reflection position. The second light receiving unit 204b receives reflected light having the position B2 as a reflection position. Further, the third light receiving unit 204c receives reflected light having the position B3 as a reflection position. In other words, the first light receiving unit 204a receives a light beam along a straight line connecting the first light receiving unit 204a and the position B1. The second light receiving unit 204b receives a light beam along a straight line connecting the second light receiving unit 204b and the position B2. Further, the third light receiving unit 204c receives a light beam along a straight line connecting the third light receiving unit 204c and the position B3. The positions B1, B2, and B3 are on the laser light emitted from the positioning light 107, the position B1 is positioned at the top, and the position B2 is positioned at a position lower than the position B1 by the distance L2, Further, a position B3 is located at a position below the position B2 by a distance L2.

  In this example, when the movement detection unit 1103 to which a light reception signal is input from each of the light reception units 204a, 204b, and 204c performs scanning by moving the cradle 202 in the extending direction, the movement detection unit 1103 receives the signal from the first light reception unit 204a. When the light receiving signal is input from the second light receiving unit 204b from the state where the light receiving signal is input, it is determined that the cradle 202 has moved downward by L2 on the scan plane. Further, when the movement detecting unit 1103 performs scanning while retracting the cradle 202, the light receiving signal is input from the second light receiving unit 204b from the state where the light receiving signal from the third light receiving unit 204c is input. In this state, it is determined that the cradle 202 has moved upward by L2 on the scan plane.

    When the movement detection unit 1103 determines that the cradle 202 has moved downward by L2 (that is, when the light receiving unit that receives reflected light has changed), the lifting unit 203 moves the support table 201 to L2. The up-and-down movement control unit 1102 outputs a control signal to the table 200 so as to move it upward.

  When the movement detection unit 1103 determines that the cradle 202 has moved upward by L2 (that is, when the light receiving unit that receives reflected light has changed), the lifting unit 203 is moved to the support table 201. The vertical movement control unit 1102 outputs a control signal to the table 200 so as to move it downward by L2.

  That is, the up-and-down movement control unit 1102 is an example of an embodiment of a correction unit according to the present invention, as in the modification of the first embodiment.

  Based on the detection by the movement detection unit 1103, the movement detection unit 1101 performs the cradle 202 in the same manner as in the modification of the first embodiment so that the acceleration of the cradle 202 moving in the horizontal direction is constant. The driving force of the motor that moves the motor horizontally is controlled.

  Now, a photographing operation in a modification of the second embodiment will be described. When scanning is performed by moving the cradle 202 out of the support base 201, the cradle 202 is extended from the support base 201 to a scan start position as shown in FIG. Here, it is assumed that the back surface 202a of the cradle 202 is at the position B1 when the cradle 202 is fed to the scan start position. Accordingly, at the start of scanning, the first light receiving unit 204a is in a light receiving state, and a light receiving signal indicating that the first light receiving unit 204a is in a light receiving state is output to the movement detecting unit 1103 of the main controller 110.

  Then, scanning is started from the state shown in FIG. 23, and when the amount of feeding of the cradle 202 is increased and the back surface 202a of the cradle 202 is lowered to the position B2 as shown in FIG. Receive light. A light reception signal is output to the movement detection unit 1103 from the second light receiving unit 204b. As a result, the movement detection unit 1103 determines that the position of the cradle 202 on the scan surface has been lowered by L2 as compared to when the scan was started.

  When the movement detecting unit 1103 detects that the position of the cradle 202 on the scan surface has been lowered by L2 compared to the time when scanning is started, as shown in FIG. The vertical movement control unit 1102 outputs a control signal to the table 200 so as to move upward by L2. As a result, the position of the cradle 202 on the scan surface returns to the position at the start of scanning.

  When the position of the cradle 202 returns to the position at the start of scanning, the first light receiving unit 204a is again in the light receiving state. A light reception signal is output from the first light receiving unit 204 a to the movement detecting unit 1103.

  Further, when the movement detection unit 1103 detects that the position of the cradle 202 on the scan plane has been lowered by L2 compared to when scanning is started, the horizontal movement control unit 1101 feeds out from the support base 201. The driving force of the motor that moves the cradle 202 in the horizontal direction is increased so that the acceleration of the cradle 202 that moves in the direction becomes constant.

  When the feeding amount of the cradle 202 is increased and the back surface 202a of the cradle 202 is lowered to the position B2 again as shown in FIG. 26, the second light receiving unit 204b is again in the light receiving state. A light reception signal is output to the movement detection unit 1103 from the second light receiving unit 204b. As a result, the movement detection unit 1103 determines that the position of the cradle 202 on the scan plane has decreased by L2 compared to when the reflected light is received by the first light receiving unit 204a.

  When the movement detection unit 1103 detects that the position of the cradle 202 on the scan surface is lowered by L2 compared to when the reflected light is received by the first light receiving unit 204a, it is shown in FIG. As described above, the vertical movement control unit 1102 outputs a control signal to the table 200 so that the elevating unit 203 moves the support base 201 upward by L2. As a result, the position of the cradle 202 on the scan surface returns to the position at the start of scanning.

  Further, when the movement detection unit 1103 detects that the position of the cradle 202 on the scan surface has dropped by L2 compared to when the reflected light is received by the first light receiving unit 204a, the horizontal detection unit 1103 The movement control unit 1101 increases the driving force of the motor that moves the cradle 202 in the horizontal direction so that the acceleration of the cradle 202 that moves in the direction of feeding out from the support base 201 is constant.

  On the other hand, when scanning is performed by moving the cradle 202 in the direction in which the cradle 202 is retracted into the support table 201, as shown in FIG. 28, the scan is started with the cradle 202 being extended from the support table 201. Withdraw gradually. Here, it is assumed that the back surface 202a of the cradle 202 is at the position B3 at the start of scanning. Therefore, at the start of scanning, the third light receiving unit 204c enters a light receiving state, and a light receiving signal indicating that the third light receiving unit 204c is in a light receiving state is output to the movement detecting unit 1103.

  Then, when the feeding amount of the cradle 202 decreases and the back surface 202a of the cradle 202 rises to the position B2, the second light receiving unit 204b enters a light receiving state (see FIG. 24). From the second light receiving unit 204b, a light receiving signal indicating a light receiving state is output to the movement detecting unit 1103. As a result, the movement detection unit 1103 determines that the position of the cradle 202 on the scan surface has increased by L2 compared to the time when the scan was started.

  When the movement detection unit 1103 detects that the position of the cradle 202 on the scan surface has risen by L2 compared to the time when scanning is started, the elevating unit 203 moves the support table 201 over as shown in FIG. The vertical movement control unit 1102 outputs a control signal to the table 200 so as to move downward by L2. As a result, the position of the cradle 202 on the scan surface returns to the position at the start of scanning.

  When the position of the cradle 202 returns to the position at the start of scanning, the third light receiving unit 204c enters the light receiving state again. A light reception signal is output to the movement detection unit 1103 from the third light receiving unit 204c.

  Further, when the movement detection unit 1103 detects that the position of the cradle 202 on the scan surface has increased by L2 compared to the time of starting scanning, the horizontal movement control unit 1101 is retracted into the support table 201. The driving force of the motor that moves the cradle 202 in the horizontal direction is reduced so that the acceleration of the cradle 202 that moves to a constant position becomes constant.

  When the amount of feeding of the cradle 202 decreases and the back surface of the cradle 202 rises again to the position B2 as shown in FIG. 30, the second light receiving portion 204b is again in the light receiving state. From the second light receiving unit 204b, a light reception signal indicating a light receiving state is output to the movement detecting unit 1103. As a result, the movement detection unit 1103 determines that the position of the cradle 202 on the scan surface has increased by L2 compared to when the reflected light is received by the third light receiving unit 204c.

  When the movement detection unit 1103 detects that the position of the cradle 202 on the scan surface has increased by L2 compared to when the reflected light is received by the third light receiving unit 204c, it is shown in FIG. As described above, the vertical movement control unit 1102 outputs a control signal to the table 200 so that the elevating unit 203 moves the support base 201 downward by L2. As a result, the position of the cradle 202 on the scan surface returns to the position at the start of scanning.

  When the movement detection unit 1103 detects that the position of the cradle 202 on the scan surface has increased by L2 compared to when the reflected light is received by the third light receiving unit 204, the horizontal detection unit 1103 The movement control unit 1101 reduces the driving force of the motor that moves the cradle 202 in the horizontal direction so that the acceleration of the cradle 202 that moves in the direction of retracting into the support table 201 is constant.

  According to the modification of the second embodiment described above, the amount of movement of the position of the cradle 202 in the vertical direction can be detected, as in the modification of the first embodiment. Even if the position moves in the vertical direction compared to the start time, the position on the scan plane can be returned to the position at the start of the scan. Furthermore, since the cradle 202 is moved according to the amount of movement of the cradle 202 on the scan plane, it is possible to more effectively prevent the obtained tomographic image from being shifted for each scan plane. In addition, the acceleration of the cradle 202 that moves in the horizontal direction while being extended from the support table 201 can be made constant.

(Third embodiment)
Next, a third embodiment will be described. FIG. 32 is a block diagram showing a schematic configuration of an X-ray CT apparatus as an embodiment of the medical image diagnostic apparatus according to the present invention, and FIGS. 33 and 34 show the X-ray CT apparatus shown in FIG. It is a front view for demonstrating schematic structure of this gantry and a table, and demonstrating a motion of a cradle.

  In the X-ray CT apparatus 20 of this example, the light receiving unit 204 is provided on the feeding side of the cradle 202 in the support base 201. The support base 201 is provided with a laser light emitting unit 210 on the place where the light receiving unit 204 is installed. The light emitting unit 210 emits a fan-shaped light beam having an inclination with respect to a horizontal plane so that a linear light beam along the X-axis direction can be projected onto the back surface 202a of the cradle 202. It has become.

  The light receiving unit 204 receives the laser light emitted from the light emitting unit 210 and reflected by the back surface 202 a of the cradle 202. In this example, as shown in FIG. 34, when the back surface 202a of the cradle 202 is positioned at the position C, the light receiving unit 204 receives reflected light. That is, the light receiving unit 204 receives light along a straight line connecting the light receiving unit 204 and the position C.

  Now, an imaging operation in the X-ray CT apparatus 20 will be described. First, when scanning is performed by moving the cradle 202 in the direction of feeding out from the support base 201, the cradle 202 is fed out to a scan start position as shown in FIG. Here, at the start of scanning, the back surface 202a of the cradle 202 does not reach the position C, and the light receiving unit 204 does not receive reflected light. At this time, no light reception signal is input to the movement detection unit 1103.

  Then, after the start of scanning, as the amount of feeding of the cradle 202 increases, the position on the scan surface moves downward, and when the back surface 202a of the cradle 202 is lowered to position C as shown in FIG. At 204, the reflected light is received. From the light receiving unit 204, a light reception signal indicating a light receiving state is output to the movement detection unit 1103. As a result, the movement detection unit 1103 determines that the cradle 202 has moved up and down as compared to when scanning started.

  On the other hand, when scanning is performed by moving the cradle 202 in the direction in which the cradle 202 is retracted into the support base 201, the scan start position is set when the back surface 202a of the cradle 202 is positioned at the position C. Therefore, first, as shown in FIG. 34, the cradle 202 is brought out to the scanning start position. At this time, the light receiving unit 204 receives reflected light, and a light reception signal is input to the movement detection unit 1103.

  After the start of scanning, as the amount of feeding of the cradle 202 decreases, the position on the scanning surface moves upward, and when the reflected light is not received by the light receiving unit 204 as shown in FIG. 33, the movement detection is performed. The unit 1103 determines that the cradle 202 has moved up and down as compared to when the scan was started.

  Similarly to the first and second embodiments, the X-ray CT apparatus 20 of the third embodiment can detect that the position of the cradle 202 has moved in the vertical direction compared to when the scan was started. An existing positioning light 107 can be used.

  In the third embodiment, as in the modification of the first and second embodiments, by providing a plurality of the light receiving portions 204, the amount of movement of the position of the cradle 202 in the vertical direction is detected, and this cradle When the position 202 moves in the vertical direction as compared with the start of scanning, the position may be returned to the position at the start of scanning. Similarly to the first and second embodiments, the horizontal movement control unit is configured so that the acceleration of the cradle 202 moving in the horizontal direction is constant based on the amount of movement of the position of the cradle 202 in the vertical direction. 1101 may control the driving force of the cradle 202.

  The present invention has been described above with reference to the above embodiments. However, the present invention is not limited to these embodiments, and various modifications can be made without departing from the scope of the present invention. For example, the present invention can be similarly applied to an MRI apparatus, a PET (Postron Emisson Tomography) CT apparatus, and the like.

  In the modification of the first and second embodiments, the correction means in the present invention is the vertical movement control unit 1102, but is not limited thereto, and is detected by, for example, the movement detection unit 1103. The display position of the obtained image may be corrected in the vertical direction according to the amount of movement of the cradle 202.

1 is a block diagram showing a schematic configuration of a first embodiment of an X-ray CT apparatus which is an embodiment of a medical image diagnostic apparatus according to the present invention. It is a front view which shows schematic structure of the gantry and table of the X-ray CT apparatus shown in FIG. It is a figure which shows the position of the cradle at the time of a scan. It is a figure which shows the position of the cradle at the time of a scan. It is a front view which shows schematic structure of the gantry and table of the X-ray CT apparatus of the modification of 1st embodiment. In the X-ray CT apparatus of the modification of 1st embodiment, it is a figure for demonstrating the detection position of the reflected light in a light-receiving part. It is a figure for demonstrating the motion of the cradle at the time of a scan. It is a figure for demonstrating the motion of the cradle at the time of a scan. It is a figure for demonstrating the motion of the cradle at the time of a scan. It is a figure for demonstrating the motion of the cradle at the time of a scan. It is a figure for demonstrating the motion of the cradle at the time of a scan. It is a figure for demonstrating the motion of the cradle at the time of a scan. It is a figure for demonstrating the motion of the cradle at the time of a scan. It is a figure for demonstrating the motion of the cradle at the time of a scan. It is a figure for demonstrating the motion of the cradle at the time of a scan. It is a block diagram which shows schematic structure of 2nd embodiment of the X-ray CT apparatus which is one Embodiment of the medical image diagnostic apparatus which concerns on this invention. It is a front view which shows schematic structure of the gantry and table of the X-ray CT apparatus shown in FIG. It is a figure which shows the position of the cradle at the time of a scan. It is a figure which shows the position of the cradle at the time of a scan. It is a figure which shows the position of the cradle at the time of a scan. It is a front view which shows schematic structure of the gantry and table of the X-ray CT apparatus of the modification of 2nd embodiment. In the X-ray CT apparatus of the modification of 2nd embodiment, it is a figure for demonstrating the detection position of the reflected light in a light-receiving part. It is a figure for demonstrating the motion of the cradle at the time of a scan. It is a figure for demonstrating the motion of the cradle at the time of a scan. It is a figure for demonstrating the motion of the cradle at the time of a scan. It is a figure for demonstrating the motion of the cradle at the time of a scan. It is a figure for demonstrating the motion of the cradle at the time of a scan. It is a figure for demonstrating the motion of the cradle at the time of a scan. It is a figure for demonstrating the motion of the cradle at the time of a scan. It is a figure for demonstrating the motion of the cradle at the time of a scan. It is a figure for demonstrating the motion of the cradle at the time of a scan. It is a block diagram which shows schematic structure of 3rd embodiment of the X-ray CT apparatus which is one Embodiment of the medical image diagnostic apparatus which concerns on this invention. It is a front view for demonstrating schematic structure of the gantry and table of the X-ray CT apparatus shown in FIG. 32, and explaining the motion of a cradle. It is a front view for demonstrating schematic structure of the gantry and table of the X-ray CT apparatus shown in FIG. 32, and explaining the motion of a cradle.

Explanation of symbols

1,10,20 X-ray CT system (medical diagnostic imaging system)
100 Gantry (shooting part)
107 Positioning light (light emitting part)
1101 Horizontal movement control unit 1102 Vertical movement control unit 1103 Movement detection unit 200 Table 201 Support base 202 Cradle 202a Back surface 204 Light receiving unit 210 Light emitting unit

Claims (12)

An imaging unit for imaging the subject;
A table having a support base, and a cradle provided on the support base so as to be movable in the horizontal direction and for transporting the subject to the imaging unit;
A horizontal movement control unit for controlling movement of the cradle in the horizontal direction in order to pay out the cradle from the support base or retract the cradle extended from the support base;
A medical image diagnostic apparatus comprising:
A light emitting unit that irradiates light to the back surface of the cradle that is fed out from the support;
A light receiving unit that receives reflected light from a specific reflection position on the back surface of the cradle;
A medical image diagnostic apparatus comprising: a movement detection unit that detects movement of the cradle in the vertical direction based on a light receiving state of reflected light in the light receiving unit. The medical image diagnostic apparatus according to claim 1, wherein a plurality of the light receiving units are provided, and each light receiving unit is arranged to receive reflected light from different reflection positions in the vertical direction.   The medical image diagnostic apparatus according to claim 1, further comprising a correction unit configured to correct movement in the vertical direction of the cradle based on detection by the movement detection unit. When the light receiving portion that receives reflected light among the plurality of light receiving portions is changed, the cradle is moved in the vertical direction so that the vertical position on the scan surface of the cradle returns to the position at the start of photographing. The medical image diagnosis apparatus according to claim 3, further comprising a vertical movement control unit that controls the correction unit. When photographing by the photographing unit while moving the cradle in the direction of extending from the support base, the light receiving unit that receives reflected light is changed to a light receiving unit that receives reflected light from a lower reflection position. When the vertical movement control unit moves the cradle upward so as to return to the position at the start of shooting, while moving the cradle in the direction in which the cradle is retracted to the support base, When the light receiving unit that receives the reflected light is changed to a light receiving unit that receives the reflected light from a higher reflection position, the vertical movement control unit moves the cradle downward so as to return to the position at the start of photographing. The medical image diagnostic apparatus according to claim 4, wherein:   The medical image diagnostic apparatus according to claim 3, wherein the correction unit corrects a display position of the obtained image.   The medical image diagnostic apparatus according to claim 1, wherein the light reflection position on the back surface of the cradle is on the scan surface. The medical image diagnosis according to claim 1, wherein the light emitting unit is provided in the imaging unit, and the light receiving unit is provided on a feeding side of the cradle in the support base. apparatus.   The medical image diagnostic apparatus according to claim 1, wherein the light emitting unit and the light receiving unit are provided in the imaging unit. The light-emitting unit provided in the imaging unit is a positioning light for irradiating the subject on the cradle conveyed to the imaging unit with visible light to position the subject. The medical image diagnostic apparatus according to 8 or 9. The medical image diagnostic apparatus according to claim 1, wherein the light emitting unit and the light receiving unit are provided on a feeding side of the cradle in the support base. The said horizontal movement control part controls the driving force of this cradle so that the acceleration of the said cradle moving to a horizontal direction becomes fixed based on the detection in the said movement detection part. The medical image diagnostic apparatus according to any one of 11.

Images