JP2016013303A - Medical image diagnostic apparatus - Google Patents

Abstract

PROBLEM TO BE SOLVED: To cause the light projected to a subject to be significantly visible.SOLUTION: A medical image diagnostic apparatus includes a bed, a projector, a position acquisition part, and a control part. A subject is placed on the bed. The projector projects light to the subject placed on the bed. The position acquisition part acquires position information indicating a placement position of the subject on the bed. The control part controls at least one of a focal position and a projection angle of the light that the projector projects based on the acquired position information.

Description

  Embodiments described herein relate generally to a medical image diagnostic apparatus.

  2. Description of the Related Art Conventionally, in an X-ray CT (Computed Tomography) apparatus, when performing tomography of a subject, the imaging position may be confirmed using a light projection position of light projected from the projector onto the subject. At this time, the operator adjusts the position of the subject by operating the bed on which the subject is placed, but depending on the distance from the projector to the subject, the light hit condition may change and may be difficult to see. It was.

Japanese Patent Laid-Open No. 2001-224583

  The problem to be solved by the present invention is to provide a medical image diagnostic apparatus that makes it easy to see the light projected on the subject.

  The medical image diagnostic apparatus according to the embodiment includes a bed, a projector, a position acquisition unit, and a control unit. The bed places the subject. The projector projects light onto the subject placed on the bed. The position acquisition unit acquires position information indicating the placement position of the subject on the bed. The control unit controls at least one of the focal position and the projection angle of the light projected by the projector based on the acquired position information.

FIG. 1 is a block diagram illustrating a configuration of an X-ray CT apparatus (medical image diagnostic apparatus) according to an embodiment. FIG. 2 is an explanatory diagram for explaining light projection onto a subject. FIG. 3 is an explanatory diagram for explaining light projection onto a subject. FIG. 4 is an explanatory diagram illustrating one configuration of the projector. FIG. 5 is an explanatory diagram for explaining the relationship between the focal position and the beam width. FIG. 6 is an explanatory diagram for explaining the relationship between the distance from the projector and the projection width (projection angle). FIG. 7 is a flowchart illustrating an example of the operation of the X-ray CT apparatus according to the embodiment. FIG. 8 is an explanatory diagram for explaining the body shape of the subject. FIG. 9 is a flowchart showing an example of the operation of the X-ray CT apparatus according to the modification.

  Hereinafter, a medical image diagnostic apparatus according to an embodiment will be described in detail with reference to the accompanying drawings. In the following description, common constituent elements are given common reference numerals, and redundant description is omitted.

  The medical diagnostic imaging apparatus may be, for example, an X-ray CT apparatus, a magnetic resonance diagnostic apparatus (MRI), a positron emission tomography apparatus (PET), or the like. When imaging a subject placed on a bed, Any device may be used as long as it confirms the imaging position using the projection position of the light projected from the projector to the subject. In the present embodiment, an X-ray CT apparatus will be described as an example.

  FIG. 1 is a block diagram illustrating a configuration of an X-ray CT apparatus 100 (medical image diagnostic apparatus) according to the embodiment. As shown in FIG. 1, the X-ray CT apparatus 100 includes a gantry 1, a bed 2, and a console device 30.

  The gantry 1 is a device that irradiates the subject P with X-rays and outputs raw data generated based on the X-rays transmitted through the subject P to the console device 30. The gantry 1 includes an X-ray tube 10, an X-ray detector 12, a high voltage generator 13, a gantry driving device 14, a data collection unit 15, a bed operation unit 16, a vertical motion encoder 17 a, The moving encoder 17b, the left / right moving encoder 17c, the position information storage unit 18, the bed control unit 19, the projector control unit 40, and the projectors 41a, 41b, and 41c are provided.

  The X-ray tube 10 is an apparatus that generates X-rays that irradiate the subject P with a high voltage supplied from a high voltage generator 13. The X-ray detector 12 is an apparatus that detects X-rays irradiated from the X-ray tube 10 and transmitted through the subject P. The X-ray tube 10 and the X-ray detector 12 are mounted on a ring-shaped rotating frame 11 that is rotationally driven by the gantry driving device 14 at positions facing each other across the rotation axis.

  In the rotating frame 11, the subject P placed on the top plate 21 of the bed 2 is inserted into the dome opened at the center. The gantry driving device 14 rotates the rotating frame 11 so that the X-ray tube 10 and the X-ray detector 12 are rotated around the subject P while facing each other.

  The data collection unit 15 is also called a DAS (Data Acquisition System), and is a device that amplifies the signal detected by the X-ray detector 12 and further converts it into a digital signal. The data collection unit 15 outputs a digital signal obtained thereby to the console device 30 as projection data.

  The couch operating unit 16 is an input device that receives an operation on the couch driving device 22 of the couch 2 from an operator. Specifically, the couch operating unit 16 includes a vertical movement button for receiving an instruction to operate the couchtop 21 in the vertical direction (x-axis direction) by the couch driving device 22, and the couchtop driving device 22 to move the couchtop 21. Left / right movement button for accepting an instruction to operate in the left / right direction (y-axis direction), IN / OUT direction (slice direction (z-axis direction)) so that the couchtop drive device 22 moves the table 21 into and out of the dome of the gantry 1 And an operation button such as a forward / backward movement button for receiving an instruction to operate the device. The couch operating unit 16 may also have an auto home button for operating an auto home function for automatically moving the top plate 21 from an arbitrary position to a predefined home position.

  Further, the couch operating unit 16 may receive an operation (for example, lighting / extinguishing with a lighting / extinguishing switch) related to the projectors 41a, 41b, 41c from the operator. Operation instructions relating to the projectors 41 a, 41 b, 41 c are notified to the projector control unit 40 via the bed control unit 19.

  When these operation buttons are operated by the operator, the bed operation unit 16 moves the table 21 up and down, moves back and forth (in / out directions), moves left and right, and the like. Instructs the auto home function to operate.

  The vertical motion encoder 17a is a measuring instrument that detects the amount of movement of the top plate 21 in the vertical direction. When the vertical movement mechanism of the bed driving device 22 is driven by an instruction from the bed operation unit 16 or the console device 30, the vertical movement encoder 17a measures the drive amount, and based on the measured value, The height (X) of 21 is calculated and stored in the position information storage unit 18.

  The longitudinal encoder 17b is a measuring instrument that detects the amount of movement of the top plate 21 in the IN / OUT direction. The forward / backward movement encoder 17b measures the driving amount when the forward / backward movement mechanism of the bed driving device 22 is driven by an instruction from the bed operating unit 16 or the console device 30, and based on the measured value, The amount of movement 21 in the front-rear direction (Z) is calculated and stored in the position information storage unit 18.

  The left-right motion encoder 17 c is a measuring instrument that detects the amount of movement of the top plate 21 in the left-right direction. The left-right motion encoder 17c measures the drive amount when the left-right motion mechanism of the bed driving device 22 is driven by an instruction from the bed operation unit 16 or the console device 30, and based on the measured value, The amount of movement 21 in the left-right direction (Y) is calculated and stored in the position information storage unit 18.

  In the present embodiment, the position of the top plate 21 is acquired by measuring the movement amount by the vertical motion encoder 17a, the forward / backward motion encoder 17b, and the left / right motion encoder 17c. However, the present invention is not limited to this configuration. For example, the position of the top plate 21 may be acquired based on a detection value from a sensor (an ultrasonic sensor, an optical sensor, or the like) that detects the position of the top plate 21 in the vertical direction, the front-rear direction, or the left-right direction.

  The position information storage unit 18 is a memory that stores position information related to the position of the top plate 21 in the bed 2. Specifically, the position information storage unit 18 is measured by the vertical motion encoder 17a, the longitudinal motion encoder 17b, and the lateral motion encoder 17c, the height (X) of the top plate 21, and the movement of the top plate 21 in the longitudinal direction. The amount (Z) and the amount of movement (Y) of the top plate 21 in the left-right direction are stored. The bed control unit 19 and the projector control unit 40 can calculate the current position of the top plate 21 in the bed 2 by referring to the position information stored in the position information storage unit 18. For example, the height (X) of the top plate 21 from a reference position (such as a defined home position), the amount of movement of the top plate 21 in the front-rear direction (Z), and the amount of movement of the top plate 21 in the left-right direction (Y ) To calculate the current position of the top 21 with respect to the reference position.

  The bed control unit 19 is a processing unit that controls the operation of the bed 2 based on an instruction from the operator. Specifically, when the couch controller 19 is instructed by the couch controller 16 or the console device 30 to move the top plate 21 up and down, back and forth, left and right, or the auto home function, Based on the instruction, the vertical movement mechanism, the forward / backward movement mechanism, and the left / right movement mechanism of the bed driving device 22 are driven to move the top plate 21. Further, the bed control unit 19 refers to the position information storage unit 18 to obtain the height (X), the movement amount (Z) in the front-rear direction, and the movement amount (Y) in the left-right direction of the top plate 21. While the values of X, Z, and Y are within a predetermined range, interlock control is performed to permit driving of the vertical movement mechanism, the longitudinal movement mechanism, and the left-right movement mechanism.

  The projector control unit 40 controls the driving of the projectors 41a, 41b, and 41c. Specifically, the projector control unit 40 turns on / off the projectors 41a, 41b, and 41c based on an operation instruction of turning on / off from the couch operating unit 16 or the console device 30.

  The projectors 41a, 41b, and 41c are provided on the inner wall portion in the dome of the gantry 1 and are visible light such as a laser beam in a visible region in an area corresponding to an imaging position and an imaging range by the X-ray tube 10 and the X-ray detector 12. Is a light source that projects light. Specifically, the projectors 41 a and 41 b are provided on the inner wall upper part in the dome of the gantry 1, and project light to an area corresponding to the imaging position and imaging range on the upper surface of the subject P in the dome of the gantry 1. . The projector 41 c is provided on the inner wall side surface in the dome of the gantry 1, and projects light onto an area corresponding to the imaging position and imaging range of the side surface of the subject P in the dome of the gantry 1.

  2 and 3 are explanatory diagrams for explaining light projection onto the subject P. FIG. As shown in FIG. 2, the projectors 41 a and 41 b perform the projections L <b> 1 and L <b> 2 on the area corresponding to the imaging position and imaging range on the upper surface of the subject P in the dome of the gantry 1. More specifically, the projector 41a performs light projection L1 indicating the imaging center, and the projector 41b performs light projection L2 indicating the slice width during imaging. The projection L1 is a cross having a predetermined length in the front-rear direction (Z-axis direction) and the left-right direction (Y-axis direction), and indicates the imaging center by the position of the cross on the upper surface of the subject P. The light projection L2 is two parallel lines having a predetermined length in the left-right direction (Y-axis direction), and indicates a slice width at the time of imaging by an interval between two lines on the upper surface of the subject P. In the light projection L1, the imaging center in the front-rear direction may be specified by lengthening a line extending in the front-rear direction (Z-axis direction) (for example, about the slice width).

  As shown in FIG. 3, the projector 41 c performs the light projection L <b> 3 on an area corresponding to the imaging position and imaging range of the side surface of the subject P in the dome of the gantry 1. More specifically, the projector 41c performs light projection L3 indicating the imaging center. The light projection L3 is a cross having a predetermined length in the front-rear direction (Z-axis direction) and the vertical direction (X-axis direction), and indicates the imaging center by the position of the cross on the side surface of the subject P. Similarly to the light projection L2, the side surface of the subject P in the dome of the gantry 1 may perform light projection indicating the slice width at the time of imaging. Moreover, in the light projection L3, the imaging center of the front-back direction may be specified by lengthening the line extended in the front-back direction (Z-axis direction) (for example, about slice width).

  The operator turns on the projectors 41a, 41b, and 41c, and visually recognizes the light projected on the subject P from the projectors 41a, 41b, and 41c in the dome of the gantry 1, thereby detecting the X-ray tube 10 and the X-rays. The imaging position and imaging range by the device 12 can be easily confirmed.

  The projector control unit 40 controls the focal position and the projection angle of the light projected by the projectors 41a, 41b, and 41c. Specifically, the projector control unit 40 includes the height (X) of the top plate 21 stored in the position information storage unit 18, the amount of movement (Z) of the top plate 21 in the front-rear direction, and the left-right direction of the top plate 21. Based on the position of the couchtop 21 on the bed 2 based on the amount of movement (Y) to the head, the focal position and angle of projection light are controlled. Note that the projector control unit 40 may control at least one of the focal position and the projection angle of the light projected by the projectors 41a, 41b, and 41c, and is not limited to the configuration that controls both.

  FIG. 4 is an explanatory diagram illustrating one configuration of the projectors 41a, 41b, and 41c. As shown in FIG. 4, the projectors 41a, 41b, and 41c are provided in a hollow case 42 that extends in the light projecting direction (dashed line in the drawing), a substrate portion 43, a light source 44, a focus adjustment lens 45, A projection angle adjusting lens 46. The substrate unit 43 turns on / off the light source 44 based on the control from the projector control unit 40. The light source 44 may be a laser diode or the like. In the light projecting direction of the light source 44, a focus adjusting lens 45 and a light projecting angle adjusting lens 46 are placed in this order.

  The focus adjustment lens 45 is a lens that adjusts the focus position of light emitted from the light source 44 by adjusting the lens position in the light projecting direction. The focus adjustment lens 45 is supported by a lens case 48 in a case 47 that can move in the light projecting direction. The case 47 slides in the light projecting direction according to the driving of the motor 60 by a rack and pinion mechanism including a pinion gear 63 attached to the motor 60 and a rack gear 62 attached to the case 47. The motor 60 is a stepping motor, an ultrasonic motor, or the like, and is driven under the control of the projector control unit 40. The projector control unit 40 controls the focus position of the light by controlling the motor 60 to adjust the lens position of the focus adjustment lens 45 in the light projecting direction.

  The projection angle adjusting lens 46 is a lens that adjusts the projection angle of the light projected by the light source 44 by adjusting the lens position in the projection direction. Here, the projection angle indicates, for example, a projection range of light projected from the light source 44. As an example, the projection angle corresponds to the cross line length in the projections L1 and L3, the line length of the two lines in the projection L2, the two line intervals, and the like.

  The projection angle adjusting lens 46 is supported by a lens case 50 in a case 49 that can move in the projection direction. The case 49 slides in the light projecting direction according to the driving of the motor 61 by a rack and pinion mechanism including a pinion gear 65 attached to the motor 61 and a rack gear 64 attached to the case 49. The motor 61 is a stepping motor, an ultrasonic motor, or the like, and is driven under the control of the projector control unit 40. The projector control unit 40 controls the light projection angle by controlling the motor 61 to adjust the lens position of the projection angle adjusting lens 46 in the projection direction.

  FIG. 5 is an explanatory diagram for explaining the relationship between the focal positions F1 and F2 and the beam widths W1 and W2. As shown in FIG. 5, when light projection by the projectors 41a, 41b, and 41c is performed at the focal position F1, the beam width W1 is obtained at a distance D1 from the projectors 41a, 41b, and 41c. The beam width W1 corresponds to, for example, a cross line width in the light projections L1 and L3, a line width of two lines in the light projection L2, and the like. Therefore, when the subject P is at a distance D1 from the projectors 41a, 41b, and 41c, the cross line width in the projections L1 and L3 and the line width of the two lines in the projection L2 are the beam width W1. .

  Here, when the focal position F1 is left as it is, the beam width W2 is obtained at the distance D2 from the projectors 41a, 41b, and 41c. Therefore, when the position of the top plate 21 in the bed 2 moves and the subject P moves at a distance D2 from the projectors 41a, 41b, 41c, the cross line width, the projector in the projections L1, L3 The line width of the two lines in the light L2 changes from the beam width W1 to the beam width W2 (the line becomes thicker).

  Thus, if the beam width of the projections L1, L2, and L3 on the subject P changes due to the movement of the position of the top plate 21 on the bed 2, it becomes difficult for the operator to see. For this reason, the projector control unit 40 focuses the light to be projected so that the beam widths of the light projections L1, L2, and L3 to the subject P are constant based on the position of the top 21 on the bed 2. Adjust.

  Specifically, the projector control unit 40 obtains distance values (distance change values) from the projectors 41a, 41b, 41c to the subject P based on the position of the top plate 21 in the bed 2, and the obtained distance value. The focal position corresponds to (distance change value). In addition, regarding the adjustment of the focal position based on the position of the top plate 21 in the bed 2 in the projector control unit 40, the position of the top plate 21 in the bed 2, the distance value from the projectors 41a, 41b, 41c to the subject P ( (Distance change value) and the calculation formula showing the correspondence relationship such as the focus position, or the table data based on the above-mentioned correspondence relationship is prepared in advance in a memory or the like. You may carry out with reference to table data.

  For example, when the distance from the projectors 41a, 41b, and 41c to the subject P changes from the distance D1 to the distance D2, the projector control unit 40 adjusts the focal position F2 before the focal position F1 to thereby project the projector. The beam widths at the projections L1, L2, and L3 from 41a, 41b, and 41c to the subject P are fixed as the beam width W1. As a result, the cross line width in the projections L1 and L3 on the subject P and the line width of the two lines in the projection L2 are kept constant as the beam width W1, so that the subject P is placed. Even when the position of the subject P is adjusted by operating the bed 2, the light projections L 1, L 2, and L 3 are easy to see.

  FIG. 6 is an explanatory diagram for explaining the relationship between the distances D3 and D4 from the projectors 41a, 41b, and 41c and the projection width (projection angle). As shown in FIG. 6, when light is projected from the projectors 41a, 41b, and 41c at a predetermined light projection angle, at a distance D3 from the light projectors 41a, 41b, and 41c, a light projection width W3 corresponding to the light projection angle. Suppose that For this reason, at the distance D3, for example, the cross line length in the light projections L1 and L3, the line length of the two lines in the light projection L2, the distance between the two lines, and the like become the length corresponding to the light projection width W3. .

  Here, when the projection angle is left as it is, the projection width becomes shorter than the projection width W3 at the distance D4 from the projectors 41a, 41b, and 41c. Therefore, when the position of the top plate 21 on the bed 2 moves, and the subject P moves at a distance D4 from the projectors 41a, 41b, 41c, the cross line length of the projections L1, L3, The line length of the two lines and the distance between the two lines in the light L2 are shortened.

  In this way, if the projection width of the light projections L1, L2, and L3 on the subject P changes due to the movement of the position of the top plate 21 in the bed 2, it becomes difficult for the operator to see. Therefore, the projector control unit 40 projects the light to be projected so that the projection widths of the projections L1, L2, and L3 on the subject P are constant based on the position of the top plate 21 on the bed 2. Adjust the light angle.

  Specifically, the projector control unit 40 obtains distance values (distance change values) from the projectors 41a, 41b, 41c to the subject P based on the position of the top plate 21 in the bed 2, and the obtained distance value. The projection angle corresponding to (distance change value) is used. In addition, regarding the adjustment of the projection angle based on the position of the top plate 21 on the bed 2 in the projector control unit 40, the position of the top plate 21 on the bed 2 and the distance value from the projectors 41a, 41b, 41c to the subject P. (Distance change value) and calculation formulas indicating correspondence relationships such as projection angles may be calculated, or table data based on the above correspondence relationships is prepared in a memory or the like in advance. The table data may be referred to.

  For example, when the distance from the projectors 41a, 41b, and 41c to the subject P changes from the distance D3 to the distance D4, the projector control unit 40 adjusts the projector angle to a larger projection angle, thereby projecting the projectors 41a, 41a, The projection widths of the projections L1, L2, and L3 from 41b and 41c to the subject P are fixed as the projection width W3. As a result, the cross line lengths of the projections L1 and L3 on the subject P, the line lengths of the two lines in the projection L2 and the interval between the two lines, and the like are kept constant. Even when the position of the subject P is adjusted by operating the sleeper 2, the projections L 1, L 2 and L 3 are easy to see.

  Returning to FIG. 1, the bed 2 is a table on which the subject P to be imaged is placed, and includes a top plate 21, a bed driving device 22, and a base frame 23.

  The top plate 21 is a plate on which the subject P is placed, and is moved by the bed driving device 22 in the vertical direction (x-axis direction shown in FIG. 1), the IN / OUT direction (z-axis direction shown in FIG. 1), and the left-right direction ( It is moved in the y-axis direction shown in FIG.

  The bed driving device 22 is a device (moving mechanism) that adjusts the position of the subject P by moving the top plate 21 in the vertical direction, the IN / OUT direction, and the horizontal direction on the base frame 23. The couch driving device 22 includes a motor that is driven under the control of the couch controller 19 and a movable unit that is driven by the motor. In addition, a left-right movement mechanism for moving in the left-right direction and a back-and-forth movement mechanism for moving the top plate 21 back and forth in the IN / OUT direction are provided. The base frame 23 is a base that supports the bed driving device 22 and fixes the bed 2 to the floor surface.

  The console device 30 accepts the operation of the X-ray CT apparatus 100 by the operator and reconstructs an image from the projection data collected by the gantry 1. Specifically, the console device 30 includes an input unit 31, a display unit 32, a gantry bed drive / scan control unit 33, an image processing unit 37, an image storage unit 38, and a system control unit 39.

  The input unit 31 is a mouse, a keyboard, or the like, and is used by an operator to input various instructions to the X-ray CT apparatus 100. For example, the input unit 31 accepts setting of shooting conditions and accepts setting of ROI. Further, the input unit 31 receives a movement instruction for the top plate 21 and instructions for turning on / off the projectors 41a, 41b, and 41c.

  The display unit 32 is a display such as an LCD (Liquid Crystal Display) and displays various types of information. For example, the display unit 32 displays an image stored in the image storage unit 38, a GUI (Graphical User Interface) for receiving various instructions from the operator, and the like.

  The system control unit 39 controls the X-ray CT apparatus 100 as a whole by controlling the gantry 1, the bed 2, and the console device 30. For example, the system control unit 39 controls the gantry bed drive / scan control unit 33 and the image processing unit 37 to collect projection data, and reconstructs an image from the collected projection data. When the system control unit 39 receives an instruction to move the top plate 21 from the operator, the system control unit 39 controls the gantry bed driving / scanning control unit 33 to move the top plate 21.

  The image processing unit 37 performs various processes on the projection data generated by the data collecting unit 15. Specifically, the image processing unit 37 performs preprocessing such as sensitivity correction on the projection data generated by the data collection unit 15, and reconstructs an image based on the reconstruction conditions instructed from the system control unit 39. Then, the reconstructed image is stored in the image storage unit 38.

  The gantry bed driving / scanning control unit 33 controls the high voltage generator 13 and the gantry driving device 14 based on the imaging conditions instructed by the system control unit 39 under the control of the system control unit 39. Further, the gantry bed drive / scan control unit 33 may control the top plate 21 based on an instruction to move the top plate 21 instructed by the system control unit 39 under the control of the system control unit 39.

  FIG. 7 is a flowchart illustrating an example of the operation of the X-ray CT apparatus 100 according to the embodiment. More specifically, FIG. 7 is a flowchart illustrating the operation of the projectors 41 a, 41 b, 41 c according to the movement of the top plate 21 in the bed 2.

  As shown in FIG. 7, when the process is started, the bed control unit 19 operates the bed (moving the table 21 up and down, moving back and forth, moving left and right) according to the movement of the table 21 from the table operation unit 16 or the console device 30. Motion operation) is received (S10). Next, the bed control unit 19 drives the bed 2 based on the received bed operation (S20). Specifically, the bed control unit 19 drives the vertical movement mechanism, the forward / backward movement mechanism, and the left / right movement mechanism of the bed driving device 22 according to operations of the vertical movement, forward / backward movement, and left / right movement of the top plate 21 to The plate 21 is moved.

  Next, the vertical motion encoder 17a, the longitudinal motion encoder 17b, and the left / right motion encoder 17c are configured such that the height (X) of the top plate 21, the amount of movement (Z) of the top plate 21 in the front-rear direction, and the horizontal direction of the top plate 21. The position information relating to the position of the top board 21 such as the amount of movement (Y) is acquired (S30). The position information acquired in S30 is stored in the position information storage unit 18.

  Next, the projector control unit 40, based on the position information of the top plate 21 stored in the position information storage unit 18, the lens positions of the focus adjustment lens 45 and the projection angle adjustment lens 46 in the projectors 41a, 41b, 41c. The lens is driven to adjust (S40). This lens driving may be performed in real time when the top plate 21 of the bed 2 is moved, or may be performed when the top plate 21 of the bed 2 is moved and temporarily stopped.

  For example, the projector control unit 40 confirms the update of the position information stored in the position information storage unit 18 in a predetermined cycle (several milliseconds for real time, and when paused for pause). When the position information is updated, the projector control unit 40 determines the height (X) of the top plate 21 stored in the position information storage unit 18, the amount of movement (Z) of the top plate 21 in the front-rear direction, and The size of the subject P placed on the top 21 at the position of the top 21 in the bed 2 based on the amount of movement (Y) of the top 21 in the left-right direction (for example, the height direction (x The offset (for example, a fixed value) corresponding to the thickness in the axial direction) and the width in the left-right direction (y-axis direction) is added, and the distance from the projectors 41a, 41b, 41c to the subject P is obtained. Next, the projector control unit 40, based on the distance from the projectors 41a, 41b, 41c to the subject P, the focus adjustment lens 45 and the projection angle so that the beam width and the projection width are constant. The position of the adjustment lens 46 is adjusted.

  Specifically, for the projectors 41 a and 41 b that project light on the upper surface of the subject P, the projector control unit 40 determines the height (X) value of the top 21 stored in the position information storage unit 18. Based on the thickness of the subject P placed on the bed 2 in the height direction (x-axis direction), the distance from the projectors 41a and 41b to the upper surface of the subject P is obtained. Next, the projector control unit 40, based on the distance from the projectors 41a and 41b to the upper surface of the subject P, the focus adjustment lens 45 and the projection angle so that the beam width and the projection width are constant. The position of the adjustment lens 46 is adjusted. As a result, in the X-ray CT apparatus 100, even when the position of the subject P is adjusted by operating the bed 2 on which the subject P is placed, the X-ray CT apparatus 100 on the upper surface of the subject P in the dome of the gantry 1. The projections L1 and L2 from the projectors 41a and 41b are easy to see.

  For the projector 41 c that projects light onto the side surface of the subject P, the projector controller 40 includes a value of the amount of movement (Y) in the left-right direction of the top 21 stored in the position information storage unit 18, and Based on the width in the left-right direction (y-axis direction) of the subject P placed on the bed 2, the distance from the projector 41 c to the side surface of the subject P is obtained. Next, the projector controller 40 adjusts the focus adjustment lens 45 and the projection angle adjustment so that the beam width and the projection width are constant based on the distance from the projector 41 c to the side surface of the subject P. The position of the lens 46 is adjusted. Thereby, in the X-ray CT apparatus 100, even when the position of the subject P is adjusted by operating the bed 2 on which the subject P is placed, the X-ray CT apparatus 100 is arranged on the side surface of the subject P in the dome of the gantry 1. The light projection L3 from the light projector 41c is easy to see.

(Modification)
Next, patient information related to the body shape of the subject P is acquired, and an offset (for example, a correction value that is variable in position) based on the body shape indicated by the acquired patient information is added to the position information of the top plate 21, A modification in which the lens positions of the focus adjustment lens 45 and the projection angle adjustment lens 46 in the projectors 41a, 41b, and 41c are adjusted will be described.

  FIG. 8 is an explanatory diagram for explaining the body shape of the subject P. As shown in FIG. 9, the body shape of the subject P is such that the top 21 is at the home position at the head position (z1), chest position (z2), abdominal position (z3), and leg position (z4) from the top of the head. The thicknesses (x1, x2, x3, x4) in the height direction (x-axis direction) and the widths (y1, y2, y3, y4) in the left-right direction (y-axis direction) with respect to the references K1, K2 are different. Further, the head position from the top (z1), the chest position (z2), the abdominal position (z3), and the leg position (z4) also differ for each subject P due to differences in height and sex.

  This difference in the body shape of the subject P affects the distance from the projectors 41a, 41b, 41c to the subject P, and the appearance of the light projections L1, L2, L3 from the projectors 41a, 41b, 41c to the subject P. Affects. Therefore, by adding the offset (correction value) based on the body shape of the subject P to the position information of the top plate 21, the distance from the projectors 41a, 41b, 41c to the subject P can be obtained more accurately. The light projections L1, L2, and L3 from the light projectors 41a, 41b, and 41c can be made easy to see according to the body shape of the subject P.

  FIG. 9 is a flowchart showing an example of the operation of the X-ray CT apparatus 100 according to the modification. More specifically, FIG. 9 is a flowchart illustrating the operation of the projectors 41a, 41b, and 41c according to the movement of the couchtop 21 in the bed 2 and the patient information indicating the body type of the subject P.

  As shown in FIG. 9, the projector control unit 40 acquires patient information indicating the body type of the subject P (S31). Specifically, the projector control unit 40 acquires patient information input by the operator through the input unit 31 of the console device 30 or the like. S31 related to the acquisition of the patient information may be performed any time before the position information correction process (S32) performed after the acquisition of the position information (S30).

  The patient information indicating the body shape of the subject P may be head circumference, chest circumference, abdominal circumference, foot thickness, age, height, weight, sex, and the like. Further, table data indicating correspondence between patient information and standard body shape is stored in a memory, and a standard body shape that matches some information (for example, age, height, weight, sex) is obtained. Also good.

  Next, the projector control unit 40 corrects the position information acquired in S30 based on the body shape indicated by the acquired patient information (S32). Specifically, the projector control unit 40 is information (for example, the amount of movement (Z) in the front-rear direction of the top plate 21 stored in the position information storage unit 18 and the body shape in the body axis direction (z-axis direction)). The projection light from the projectors 41a, 41b, 41c to the subject P is transmitted to any position of the head position (z1), the chest position (z2), the abdominal position (z3), and the leg position (z4). Judgment is made. Next, the projector control unit 40 determines the body shape (height direction (x-axis direction) at the position determined among the head position (z1), the chest position (z2), the abdominal position (z3), and the leg position (z4). ) (X1, x2, x3, x4) and the width (y1, y2, y3, y4) in the left-right direction (y-axis direction)). Next, the projector control unit 40 corrects the position information in the height direction (x-axis direction) and the left-right direction (y-axis direction) based on the read value.

  In this way, by performing the lens driving by adding the offset (correction value) based on the body shape of the subject P to the position information of the top plate 21, the light projections L1, L2 from the projectors 41a, 41b, 41c are performed. , L3 can be easily seen according to the body shape of the subject P.

  According to at least one embodiment described above, the light projected on the subject can be easily seen.

  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 embodiments can be implemented in various other forms, and various omissions, replacements, and changes can be made without departing from the spirit of the invention. These embodiments and their modifications are included in the scope and gist of the invention, and are also included in the invention described in the claims and the equivalents thereof.

  DESCRIPTION OF SYMBOLS 100 ... X-ray CT apparatus, 1 ... Stand, 2 ... Bed, 10 ... X-ray tube, 11 ... Rotating frame, 12 ... X-ray detector, 16 ... Bed operation part, 17a ... Vertical motion encoder, 17b ... Forward / backward motion encoder , 17c ... Left-and-right encoder, 18 ... Position information storage unit, 19 ... Bed control unit, 21 ... Top plate, 22 ... Bed driving device, 30 ... Console device, 40 ... Projector control unit, 41a, 41b, 41c ... Projector 42 ... Case, 43 ... Substrate unit, 44 ... Light source, 45 ... Focus adjustment lens, 46 ... Light projection angle adjustment lens, 60, 61 ... Motor, 62, 64 ... Rack gear, 63, 65 ... Pinion gear, D1, D2, D3, D4 ... Distance, F1, F2 ... Focus position, K1, K2 ... Reference, L1, L2, L3 ... Projection, P ... Subject, W1, W2 ... Beam width, W3 ... Projection width

Claims (5)

A bed on which the subject is placed;
A projector that projects light onto the subject placed on the bed;
A position acquisition unit for acquiring position information indicating the position of the bed;
A control unit for controlling at least one of a focal position and a projection angle of light projected by the projector based on the acquired position information;
A medical image diagnostic apparatus comprising: An operation unit for receiving a movement instruction relating to movement of the subject;
A movement mechanism that moves the position of the bed based on the movement instruction,
The position acquisition unit acquires the position information based on a movement amount in the movement mechanism;
The medical image diagnostic apparatus according to claim 1. The projector projects light on the upper surface of the subject placed on the bed,
The control unit, based on a distance between the projector and the upper surface of the subject, based on the acquired position information, the focal position and the light of the light projected by the projector on the upper surface of the subject Control at least one of the corners,
The medical image diagnostic apparatus according to claim 1 or 2. The projector projects light onto a side surface of a subject placed on the bed,
The control unit, based on the acquired position information, based on the distance between the projector and the side surface of the subject, the focal position of the light projected by the projector on the upper surface of the subject and the projection Control at least one of the corners,
The medical image diagnostic apparatus according to claim 1 or 2. A patient information acquisition unit for acquiring patient information relating to the body type of the subject;
The control unit corrects the acquired position information based on the acquired patient information, and based on the corrected position information, at least a focal position and a projection angle of light projected by the projector. Control one side,
The medical image diagnostic apparatus according to any one of claims 1 to 4.

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