JP6109479B2 - X-ray CT system - Google Patents

Description

  Embodiments described herein relate generally to an X-ray CT apparatus.

  An X-ray CT (Computed Tomography) apparatus is an apparatus that scans a subject using X-rays and processes the collected data by a computer, thereby imaging the inside of the subject.

  Specifically, the X-ray CT apparatus emits X-rays to a subject a plurality of times from different directions, detects X-rays transmitted through the subject with an X-ray detector, and generates a plurality of detection data. collect. The collected detection data is A / D converted by the data collection unit and then transmitted to the console device. The console device pre-processes the detection data and creates projection data. Then, the console device performs reconstruction processing based on the projection data, and creates tomographic image data or volume data based on a plurality of tomographic image data. Volume data is a data set representing a three-dimensional distribution of CT values corresponding to a three-dimensional region of a subject.

  The X-ray CT apparatus can perform MPR (Multi Planar Reconstruction) display by rendering the volume data in an arbitrary direction. The MPR-displayed cross-sectional image (hereinafter, referred to as “MPR image”) includes, for example, an axial image showing a cross section orthogonal to the body axis, a sagittal image showing a cross section of the subject along the body axis, and There is a coronal image showing a cross section of the subject across the body axis. Furthermore, an arbitrary cross-sectional image (oblique image) in the volume data is also included in the MPR image.

  In CT fluoroscopy (CTF) performed using an X-ray CT apparatus, an image is created in real time by reducing the collection rate of detection data and the time required for reconstruction processing. This CT fluoroscopy is used, for example, when confirming the positional relationship between a puncture needle and a part from which a specimen is collected during a biopsy.

JP 2002-34969 A

  When a biopsy is performed on a subject while displaying an MPR image obtained by CT fluoroscopy, scanning and puncture may be alternately performed. Specifically, first, an MPR image of the subject is acquired by CT fluoroscopy. A doctor or the like performs puncturing while referring to the MPR image. At this time, for example, in order to confirm the positional relationship between the tip of the puncture needle and the part from which the specimen is collected, CT fluoroscopy is performed again at a stage where puncture is performed to some extent. While referring to the MPR image obtained by another CT fluoroscopy, the doctor or the like further moves the puncture needle toward the target site. This operation is repeated until the biopsy is completed.

  During such repetitive operations, the needle tip of the puncture needle may be displayed near the edge of the screen. For example, when the needle tip of the puncture needle is displayed near the upper edge of the screen, the lower region of the needle tip of the puncture needle can be grasped, but the upper region of the needle tip of the puncture needle can be grasped. difficult. Therefore, it is difficult to perform puncturing work accurately and efficiently.

  The embodiment has been made to solve the above-described problems, and an object thereof is to provide an X-ray CT apparatus capable of achieving accuracy and efficiency of a puncture operation.

The X-ray CT apparatus of the embodiment is an apparatus that creates volume data based on a result of scanning a subject into which a puncture needle is inserted with X-rays. The X-ray CT apparatus includes a display control unit, an input unit, a specifying unit, and a scan control unit. The display control unit displays a plurality of MPR images created based on the first volume data obtained by the first scan. The specifying unit specifies the needle tip position of the puncture needle in the first MPR image selected by the input unit among the plurality of displayed MPR images . The scan control unit shifts the scan center of the first scan based on the specified needle tip position and the center of the first MPR image to execute the second scan. The display control unit causes the display unit to display a second MPR image created based on the second volume data obtained by the second scan.

1 is a block diagram of an X-ray CT apparatus according to a first embodiment. It is a figure which shows the display screen of the display part which concerns on 1st Embodiment. It is a figure which shows the display screen of the display part which concerns on 1st Embodiment. It is a block diagram which shows the structure of the analysis part which concerns on 1st Embodiment. It is a schematic diagram which shows the relationship between the scan center position before the movement of a bed top plate, and a needle point position. It is a schematic diagram which shows the relationship between the scan center position and needlepoint position after the bed top plate moves. It is a figure which shows the 1st MPR image drawn on the display screen. It is a figure which shows the 2nd MPR image drawn on the display screen. It is a figure for demonstrating the difference of the coordinate of the needle point in a MPR image, and the coordinate of a scanning center. It is a figure for demonstrating the difference of the coordinate of the needle point in a MPR image, and the coordinate of a scanning center. It is a flowchart which shows the outline | summary of operation | movement of the X-ray CT apparatus which concerns on 1st Embodiment. It is a block diagram of the X-ray CT apparatus which concerns on 2nd Embodiment. It is a block diagram which shows the structure of the analysis part which concerns on 2nd Embodiment. It is a figure for demonstrating the difference of the coordinate of the needle point in a three-dimensional image, and the coordinate of a scan center. It is a figure for demonstrating the difference of the coordinate of the needle point in a three-dimensional image, and the coordinate of a scan center. It is a flowchart which shows the outline | summary of operation | movement of the X-ray CT apparatus which concerns on 2nd Embodiment. It is a block diagram of the X-ray CT apparatus which concerns on 3rd Embodiment. It is a figure which shows the display screen of the display part which concerns on 3rd Embodiment. It is a figure for demonstrating the change of the display screen of the display part which concerns on 3rd Embodiment. It is a figure for demonstrating the change of the display screen of the display part which concerns on 3rd Embodiment. It is a figure for demonstrating the change of the display screen of the display part which concerns on 3rd Embodiment. It is a flowchart which shows the outline | summary of operation | movement of the X-ray CT apparatus which concerns on 3rd Embodiment.

(First embodiment)
A configuration of the X-ray CT apparatus 1 according to the first embodiment will be described with reference to the drawings. Since “image” and “image data” have a one-to-one correspondence, in the present embodiment, they may be regarded as the same.

<Overall configuration of X-ray CT apparatus 1>
As shown in FIG. 1, the X-ray CT apparatus 1 includes a gantry device 10, a bed device 30, and a console device 40.

[Mounting device (gantry)]
The gantry device 10 is an apparatus that irradiates the subject E with X-rays and collects detection data of the X-rays transmitted through the subject E. The gantry device 10 includes an X-ray generator 11, an X-ray detector 12, a rotating body 13, a high voltage generator 14, a gantry driver 15, an X-ray diaphragm 16, a data collector 18, And an aperture drive unit 19.

  The X-ray generator 11 includes an X-ray tube that generates X-rays (for example, a vacuum tube that generates a conical or pyramidal beam (not shown)). The generated X-ray is exposed to the subject E. The X-ray detection unit 12 includes a plurality of X-ray detection elements (not shown). The X-ray detection unit 12 detects X-ray intensity distribution data (hereinafter sometimes referred to as “detection data”) indicating the intensity distribution of X-rays transmitted through the subject E with an X-ray detection element, and the detection data is Output as a current signal. As the X-ray detection unit 12, for example, a two-dimensional X-ray detector (plane detector) in which a plurality of detection elements are arranged in two directions (slice direction and channel direction) orthogonal to each other is used. The plurality of X-ray detection elements are provided, for example, in 320 rows along the slice direction. By using a multi-row X-ray detector in this way, it is possible to image a three-dimensional imaging region having a width in the slice direction by one rotation scan (volume scan). The slice direction corresponds to the body axis direction of the subject E, and the channel direction corresponds to the rotation direction of the X-ray generation unit 11.

  The rotating body 13 is a member that supports the X-ray generation unit 11 and the X-ray detection unit 12 so as to face each other with the subject E interposed therebetween. The rotating body 13 has an opening 13a penetrating in the slice direction. In the gantry device 10, the rotating body 13 is arranged so as to rotate in a circular orbit around the subject E.

  The high voltage generator 14 applies a high voltage to the X-ray generator 11. The X-ray generator 11 generates X-rays based on the high voltage.

  The gantry driving unit 15 rotates the rotating body 13 around the subject E based on the gantry driving control signal output from the scan control unit 41. Here, the rotator 13 is based on the movement control signal output from the scan control unit 41, the body axis direction (slice direction: z-axis direction), vertical direction (x-axis direction), left-right direction ( move in the y-axis direction). As the rotator 13 moves, the X-ray generator 11 and the X-ray detector 12 supported by the rotator 13 move.

  The X-ray diaphragm section 16 has a slit (opening) having a predetermined width, and by changing the width of the slit, the fan angle (expansion angle in the channel direction) of X-rays exposed from the X-ray generation section 11 and X Adjust the cone angle of the line (the spread angle in the slice direction). The diaphragm drive unit 19 drives the X-ray diaphragm unit 16 so that the X-rays generated by the X-ray generation unit 11 have a predetermined shape.

  A data collection unit 18 (DAS: Data Acquisition System) collects detection data from the X-ray detection unit 12 (each X-ray detection element). The data collection unit 18 converts the collected detection data (current signal) into a voltage signal, periodically integrates and amplifies the voltage signal, and converts the voltage signal into a digital signal. Then, the data collection unit 18 transmits the detection data converted into the digital signal to the console device 40 (processing unit 42 (described later)). When performing CT fluoroscopy, it is desirable that the reconstruction processing unit 42b (described later) performs reconstruction processing in a short time based on the detection data collected by the data collection unit 18 and obtains a CT image in real time. Accordingly, the data collection unit 18 shortens the detection data collection rate.

[Bed equipment]
The couch device 30 is a device for placing and moving the subject E to be imaged. The couch device 30 includes a couch 31 and a couch driving unit 32. The couch 31 includes a couch top 33 for placing the subject E and a base 34 that supports the couch top 33. The couch top 33 is moved by the couch driving unit 32 in the body axis direction of the subject E (front-rear direction: insertion / removal direction with respect to the opening 13a of the rotating body 13) and in the left-right direction (direction orthogonal to the body axis direction). It is possible to do. The base 34 can move the bed top 33 in the vertical direction (direction perpendicular to the body axis direction) by the bed driving unit 32.

[Console device]
The console device 40 is used for operation input to the X-ray CT apparatus 1. Further, the console device 40 has a function of reconstructing CT image data (tomographic image data and volume data) representing the internal form of the subject E from the detection data collected by the gantry device 10. The console device 40 includes a scan control unit 41, a processing unit 42, a display control unit 44, an analysis unit 45, a display unit 46, and a control unit 48.

  The scan control unit 41, the processing unit 42, the analysis unit 45, the display control unit 44, and the control unit 48 are, for example, a CPU (Central Processing Unit), a GPU (Graphic Processing Unit), or an ASIC (Application Specific Integrated Circuit). And a storage device (not shown) such as a ROM (Read Only Memory), a RAM (Random Access Memory), or an HDD (Hard Disc Drive). The storage device stores a control program for executing the function of each unit. A processing device such as a CPU executes the functions of each unit by executing each program stored in the storage device.

  The scan control unit 41 controls various operations related to X-ray scanning. For example, the scan control unit 41 controls the high voltage generation unit 14 to apply a high voltage to the X-ray generation unit 11. The scan control unit 41 controls the gantry driving unit 15 so as to rotationally drive the rotating body 13. The scan control unit 41 controls the aperture drive unit 19 to operate the X-ray aperture unit 16. The scan control unit 41 controls the bed driving unit 32 to move the bed top plate 33.

  The processing unit 42 executes various processes on the detection data transmitted from the gantry device 10 (data collection unit 18). The processing unit 42 includes a preprocessing unit 42a, a reconstruction processing unit 42b, and an MPR rendering processing unit 42c.

  The pre-processing unit 42a performs pre-processing such as logarithmic conversion processing, offset correction, sensitivity correction, and beam hardening correction on the detection data detected by the gantry device 10 (X-ray detection unit 12) to produce projection data (raw data). Data).

  The reconstruction processing unit 42b creates CT image data (tomographic image data or volume data) based on the projection data created by the preprocessing unit 42a. For reconstruction of tomographic image data, any method such as a two-dimensional Fourier transform method, a convolution / back projection method, or the like can be employed. Volume data is created by interpolating a plurality of reconstructed tomographic image data. For the reconstruction of volume data, for example, an arbitrary method such as a cone beam reconstruction method, a multi-slice reconstruction method, an enlargement reconstruction method, or the like can be adopted. As described above, a wide range of volume data can be reconstructed by volume scanning using a multi-row X-ray detector.

  The MPR rendering processing unit 42c renders the volume data created (reconstructed) by the reconstruction processing unit 42b in an arbitrary direction to render a plurality of MPR images (axial images, sagittal images, coronal images having three orthogonal cross sections). Create

  In the present embodiment, a sagittal image created by the MPR rendering processing unit 42c by the display control unit 44 is displayed on the display screen 46a of the display unit 46 (see FIGS. 2A and 2B). 2A and 2B show an example in which a sagittal image is displayed, but an axial image or a coronal image may be displayed.

  The MPR rendering processing unit 42c can also create an oblique image that is an image of an arbitrary cross section in the volume data as an MPR image. For example, a line segment is drawn on a portion of the MPR image displayed on the display unit 46 where a cross section is desired to be shown. The MPR rendering processing unit 42c creates an oblique image by rendering volume data in a predetermined direction with the line segment as a reference.

  The display control unit 44 performs various controls related to image display. For example, control is performed to display the MPR image (the sagittal image in the example of FIGS. 2A and 2B) created by the MPR processing unit 42c on the display unit 46.

  As shown in FIG. 3, the analysis unit 45 includes a specifying unit 51, a displacement calculation unit 52, and a movement amount determination unit 53.

  The specifying unit 51 specifies an MPR image on which a needle point SP, which will be described later, is displayed from among a plurality of MPR images, and the position of the needle point SP of the puncture needle in the specified MPR image (hereinafter referred to as “needle point position SP”). And the specified needle tip position SP is designated as the needle tip position in the image area. When specifying the MPR image (the MPR image in the specific region) in which the needle tip is displayed from among the plurality of MPR images, the specifying unit 51, for example, obtains the difference between the adjacent MPR images to thereby determine the MPR image in the specific region. Can be specified.

  Specifically, the specifying unit 51 takes a difference between MPR images, specifies an MPR image having a large difference, performs image processing such as edge detection on the specified MPR image, and outputs the MPR image in the specified region. Identify. Then, the specifying unit 51 specifies the specified MPR image as an MPR image on which the needle tip is displayed.

  Next, the specifying unit 51 compares the luminance value of the pixel constituting the designated MPR image with a preset threshold value, and sets the coordinate value of a pixel (pixel) larger (or smaller) than the threshold value to the needle of the puncture needle It is specified as the tip position SP. Here, the threshold value is a luminance value determined in advance corresponding to the needle tip of the puncture needle, and is a value for determining whether or not the needle tip of the puncture needle is included in the pixel.

  Next, the specifying unit 51 specifies the coordinate value of the specified pixel as the needle tip position SP of the puncture needle in the image area. In this way, the needle tip position SP is automatically specified by the specifying unit 51.

[Displacement calculation unit]
Hereinafter, the operation of the displacement calculation unit will be described with reference to FIGS. 4A, 4B, 5A, 5B, 6A, and 6B.
The displacement calculation unit 52 obtains the displacement between the position of the needle tip SP of the designated puncture needle PN and the center CP of the MPR image. Specifically, as shown in FIGS. 6A and 6B, this displacement is the difference between the coordinate values (X1, Y1, Z1) of the needle tip SP and the coordinate values (X2, Y2, Z2) of the center CP of the MPR image. It is obtained by taking (X2-X1, Y2-Y1, Z2-Z1). The above description is based on the premise that the center CP of the MPR image and the scan center SC in the same coordinate system coincide. In this way, the displacement is obtained by taking the difference between the coordinate value of the needle tip SP and the coordinate value of the center CP of the MPR image (displaced from FIG. 4A to FIG. 4B, displaced from FIG. 5A to FIG. 5B, and from FIG. 6A). Displacement to FIG. 6B).

  The movement amount determination unit 53 determines a relative movement amount between the couch top 33 and the gantry device 10 corresponding to the displacement obtained by the displacement calculation unit 52. The amount of movement is obtained by converting the displacement into a displacement in actual coordinates. For example, a displacement of 50 pixels is a movement amount of 25 mm on the actual coordinates.

  In the present embodiment, the display control unit 44 causes the display unit 46 to display the MPR image of the cross section at the position of the image region stored in the storage unit 45 in the volume data obtained by scanning.

  The control unit 48 performs overall control of the X-ray CT apparatus 1 by controlling operations of the gantry device 10, the couch device 30, and the console device 40. For example, the control unit 48 controls the scan control unit 41 to cause the gantry device 10 to perform a preliminary scan and a main scan and collect detection data. In addition, the control unit 48 controls the processing unit 42 to perform various processing (preprocessing, reconstruction processing, MPR processing, etc.) on the detected data. Alternatively, the control unit 48 controls the display control unit 44 to display a CT image on the display unit 46 based on the image data created by the processing unit 42.

<Operation>
Below, with reference to FIG. 7, operation | movement of the X-ray CT apparatus 1 which concerns on this embodiment is demonstrated. Here, CT fluoroscopy and puncture are performed alternately, and puncture needle PN is applied to biopsy target S (see FIGS. 2A, 2B, 4A, 4B, 5A, 5B, 6A, and 6B). The operation when puncturing is described.

  In starting the puncture, the X-ray CT apparatus 1 first performs an X-ray scan (first scan) on the subject E to create first volume data.

  Specifically, the X-ray generation unit 11 emits X-rays to the subject E. The X-ray detection unit 12 detects X-rays that have passed through the subject E, and acquires detection data (S10). In the present embodiment, detection data for one rotation is acquired. Detection data detected by the X-ray detection unit 12 is collected by the data collection unit 18 and sent to the processing unit 42 (pre-processing unit 42a).

  The preprocessing unit 42a performs preprocessing on the detection data acquired in S10 and creates projection data (S11). The created projection data is sent to the reconstruction processing unit 42b based on the control of the control unit 48.

  The reconstruction processing unit 42b creates a plurality of tomographic image data based on the projection data created in S11. Next, the reconstruction processing unit 42b creates first volume data by interpolating a plurality of tomographic image data (S12).

  The MPR rendering processor 42c creates a plurality of MPR images by rendering the first volume data created in S12 in an arbitrary direction. The specifying unit 51 specifies the first MPR image including the needle tip of the puncture needle from the plurality of MPR images.

  The MPR rendering processor 42c creates three orthogonal MPR images (axial image, sagittal image, coronal image) in the designated first MPR image. In the present embodiment, a sagittal image is created as an MPR image, and the created sagittal image is displayed on the display unit 46 by the display control unit 44 as a first MPR image (S13, see FIG. 2A).

  Next, the specifying unit 51 obtains the coordinate value of the needle tip of the puncture needle (S14). Then, the displacement calculation unit 52 calculates the displacement between the coordinate value (X1, Y1, Z1) of the needle tip of the designated puncture needle and the position (X2, Y2, Z2) of the scan center SC (MPR image center CP). Calculate (S15).

That is, as described above, since it is assumed that the center CP of the MPR image and the scan center SC in the same coordinate system coincide with each other, the displacement calculation unit 52 determines the position of the needle tip SP of the designated puncture needle PN ( X1, Y1, Z1) and the displacement (X2-X1, Y2-Y1, Z2-Z1) between the center CP (X2, Y2, Z2) of the MPR image are obtained. Then, the movement amount determination unit 53 cancels the calculated displacement (the position of the scan center SC (hereinafter referred to as “scan center position SC”) is made to coincide with the coordinate value of the needle tip SP of the puncture needle). Then, the relative movement amount between the bed top plate 33 and the gantry device 10 corresponding to this displacement is calculated (in this embodiment, the movement amount of the bed top plate 33 is calculated (S16)).
Then, a second scan start signal (not shown) including this movement amount information is sent to the scan control unit 41. This relative movement amount is a difference between the actual coordinate value before the movement of the bed top plate 33 and the gantry device 10 and the actual coordinate value after the movement. The information on the amount of movement is sent to the scan control unit 41 as new actual coordinate values of the bed top plate 33 and the gantry device 10 after movement.

  As a type of relative movement of the couch top 33 and the gantry device 10, the case where only the couch top 33 is moved, the case where only the gantry device 10 is moved, and both the couch top plate 33 and the gantry device 10 are moved. There are cases. This embodiment demonstrates the case where only the bed top plate 33 is moved based on the determined movement amount.

  The scan control unit 41 sends a movement control signal Si (see FIG. 1) to the bed top plate 33 so as to move the bed top plate 33 by the determined amount of movement. In response to the movement control signal Si, the bed top plate 33 moves up and down, moves back and forth, and / or moves left and right, and moves by the determined amount of movement. Then, the scan control unit 41 causes the subject E to perform an X-ray scan (second scan) (S17).

  The X-ray detection unit 12 detects X-rays exposed to the subject E and acquires the detection data (S18). Detection data detected by the X-ray detection unit 12 is collected by the data collection unit 18 and sent to the processing unit 42 (pre-processing unit 42a).

  The pre-processing unit 42a pre-processes the detection data acquired in S18 and creates projection data (S19). The created projection data is sent to the reconstruction processing unit 42b based on the control of the control unit 48.

  The reconstruction processing unit 42b creates a plurality of tomographic image data based on the projection data created in S19. Further, the reconstruction processing unit 42b creates second volume data by performing interpolation processing on a plurality of tomographic image data (S20).

  The MPR rendering processor 42c creates a plurality of MPR images by rendering the second volume data created in S20 in an arbitrary direction. The specifying unit 51 designates a second MPR image including the needle tip of the puncture needle from the plurality of MPR images. This designation is automatically designated based on the designation information when the first MPR image is designated in S13.

  In the present embodiment, the MPR rendering processing unit 42c creates three orthogonal MPR images (axial image, sagittal image, coronal image) in the designated second MPR image. The created second MPR image is displayed on the display unit 46 by the display control unit 44 (S21; see FIG. 2B). In the example of FIG. 2B, the sagittal image SI in the second MPR image is displayed. As can be seen from the second MPR image displayed on the display unit 46, an MPR image in which the needle tip position SP of the puncture needle and the scan center position SC in the second MPR image are matched is displayed (FIGS. 2B and 4B). (See FIGS. 5B and 6B).

  Thereafter, after the puncture is advanced to some extent, the X-ray CT apparatus 1 again scans the subject E with an X-ray scan (first scan) in order to confirm the deviation between the needle tip position SP of the puncture needle and the scan center position SC. 3 scans), volume data (third volume data) is created, and the processing from S10 to S21 is repeated.

<Effect>
The X-ray CT apparatus 1 of the present embodiment is an apparatus that creates volume data based on a result of scanning a subject E, which is a target of medical practice using a puncture needle PN, with X-rays. The X-ray CT apparatus 1 includes an MPR rendering processing unit 42c, a specifying unit 51, a displacement calculating unit 52, a scan control unit 41, and a display control unit 44. The MPR rendering processor 42c creates a first MPR image in which the puncture needle PN is drawn based on the first volume data obtained by the first scan. The specifying unit 51 specifies the position of the needle tip SP of the puncture needle PN in the created first MPR image. The displacement calculation unit 52 obtains the displacement between the specified needle tip position SP and the center CP of the first MPR image. The scan control unit 41 shifts the scan center of the first scan so as to cancel the displacement and causes the second scan to be executed. The display control unit 44 causes the display unit 46 to display the second MPR image in the same cross section as the first MPR image, which is created by the MPR rendering processing unit 42c based on the second volume data obtained by the second scan.

  Specifically, the X-ray CT apparatus 1 includes a couch top 33 on which the subject E is placed and a gantry device 10 that performs scanning. The X-ray CT apparatus 1 further includes a movement amount determination unit 53 that determines the movement amount of the relative position between the bed top plate 33 and the gantry device 10 based on the displacement. The scan control unit 41 controls the movement of the couchtop 33 and / or the gantry device 10 according to the determined movement amount.

  Therefore, as shown in FIGS. 5A and 5B, the needle tip SP of the puncture needle PN can always be displayed at the center of the display screen 46a, so that the periphery of the puncture needle PN can be clearly grasped. For this reason, it is possible to improve the accuracy and efficiency of the puncturing operation.

(Modification 1)
In the above embodiment, as a type of relative movement between the couchtop 33 and the gantry device 10, the case where only the couchtop 33 is moved has been described. A case where both the plate 33 and the gantry device 10 are moved will be described.

  The movement of the gantry device 10 includes movement by tilting the gantry in addition to vertical movement, horizontal movement, and forward / backward movement. The up / down movement, the left / right movement, and the forward / backward movement can be obtained in the same manner as in the case of the bed top 33. When tilting, coordinates before tilting (before rotation) and after tilting (after rotation) are associated using a rotation matrix of three-dimensional polar coordinates. Here, since the coordinates of the needle tip of the puncture needle and the coordinates of the scan center are known, the tilt angle is obtained by obtaining the inverse matrix of the rotation matrix described above.

  As described above, the movement amount of the gantry device 10 is obtained based on the displacement of the coordinates of the tip of the puncture needle and the coordinates of the scan center. When both the couchtop 33 and the gantry device 10 are moved, the amount of movement is obtained by combining the method of moving only the couchtop 33 and the method of moving only the gantry device 10.

(Second Embodiment)
Next, the configuration of the X-ray CT apparatus 50 according to the second embodiment will be described with reference to FIGS. 8 and 9. The X-ray CT apparatus 50 according to the present embodiment automatically designates the needle tip position SP of the puncture needle based on the volume data, and cancels the displacement between the needle tip position SP of the puncture needle and the scan center position SC. The second scan is executed by shifting the scan center of one scan. Since the configuration other than the processing unit 62 and the analysis unit 70 is the same as that of the first embodiment, detailed description may be omitted.

<Overall configuration of X-ray CT apparatus 50>
As shown in FIG. 8, the X-ray CT apparatus 50 includes a gantry device 10, a couch device 30, and a console device 60.

[Console device]
The console device 60 includes a scan control unit 41, a processing unit 62, a display control unit 44, a display unit 46, a control unit 48, and an analysis unit 70. The processing unit 62 performs various processes on the detection data transmitted from the gantry device 10 (data collection unit 18). The processing unit 62 includes a preprocessing unit 62a, a reconstruction processing unit 62b, and a volume rendering processing unit 62c.
The volume rendering processor 62c creates a three-dimensional image based on the volume data created by the reconstruction processor 62b. Specifically, the volume rendering processing unit 62c performs ray tracing on the created volume data, obtains the brightness in the voxel (CT value), and outputs image information based on this brightness to the pixels on the projection plane. By projecting, a three-dimensional image is created by three-dimensionally extracting organs and the like. The three-dimensional image is displayed on the display unit by the display control unit 44.

  As illustrated in FIG. 9, the analysis unit 70 includes a specifying unit 71, a displacement calculation unit 72, and a movement amount determination unit 73. The specifying unit 71 specifies the needle tip position based on the three-dimensional image on which the puncture needle PN created based on the volume data is drawn. Next, the specifying unit 71 specifies the specified needle tip position SP as the needle tip position in the display image area of the display unit 46.

  The specifying unit 71 compares the CT value of each voxel constituting the volume data with a preset threshold value, and uses the coordinate value of the voxel having a CT value larger (or smaller) as the needle point position SP of the puncture needle. Identify. Here, the threshold value is a predetermined CT value corresponding to the material (for example, metal) of the puncture needle, and is a value for determining whether or not the needle tip of the puncture needle is included in the voxel. It is. Next, the specifying unit 71 specifies the coordinate value of the specified voxel as the needle tip position SP of the puncture needle in the image area. In this way, the needle tip position SP is automatically specified by the specifying unit 71.

[Displacement calculation unit]
Hereinafter, the operation of the displacement calculation unit will be described with reference to FIGS. 10A and 10B.
The displacement calculation unit 72 obtains the displacement between the position of the needle tip SP of the designated puncture needle PN and the center of the three-dimensional image based on the volume data. Specifically, as shown in FIGS. 10A and 10B, this displacement is obtained by the coordinate values (x1, y1, z1) of the needle tip SP and the coordinate values (x2, y2, z2) of the center CP of the three-dimensional image. The difference (x2-x1, y2-y1, z2-z1) is obtained. Note that the above description is based on the assumption that the center CP of the three-dimensional image and the scan center SC in the same coordinate system match. In this way, the displacement is obtained by taking the difference between the coordinate value of the needle tip SP and the coordinate value of the center CP of the three-dimensional image (displacement from FIG. 10A to FIG. 10B).

  The movement amount determination unit 53 determines a relative movement amount between the couch top 33 and the gantry device 10 corresponding to the displacement obtained by the displacement calculation unit 52. This amount of movement is obtained by converting the displacement into a displacement in real space coordinates.

<Operation>
Next, the operation of the X-ray CT apparatus 50 according to the present embodiment will be described with reference to FIG. Here, an operation in the case where CT fluoroscopy and puncture are alternately performed and the puncture needle PN is punctured with respect to the target S of the puncture operation will be described.

  In starting the puncture, the X-ray CT apparatus 50 first performs an X-ray scan (first scan) on the subject E to create first volume data.

  Specifically, the X-ray generation unit 11 emits X-rays to the subject E. The X-ray detection unit 12 detects X-rays that have passed through the subject E and acquires the detection data (S30). In the present embodiment, detection data for one rotation is acquired. Detection data detected by the X-ray detection unit 12 is collected by the data collection unit 18 and sent to the processing unit 62 (pre-processing unit 62a).

  The preprocessing unit 62a performs preprocessing on the detection data acquired in S30, and creates projection data (S31). The created projection data is sent to the reconstruction processing unit 62b based on the control of the control unit 48.

  The reconstruction processing unit 62b creates a plurality of tomographic image data based on the projection data created in S31. Next, the reconstruction processing unit 62b creates first volume data by interpolating a plurality of tomographic image data (S32).

  The volume rendering processing unit 62c performs ray tracing on the first volume data created in S32, obtains the brightness in the voxel (CT value), and projects image information based on this brightness onto the pixels on the projection plane. Then, a first three-dimensional image is created by three-dimensionally extracting organs and the like. The created first three-dimensional image (FIG. 10A) is displayed on the display unit 46 by the display control unit 44 (S33). In addition, a transparent process is performed by a known method so that the needle tip of the puncture needle can be seen inside the three-dimensional image.

  Next, the specifying unit 71 specifies the needle tip position SP based on the three-dimensional image on which the puncture needle PN created based on the volume data is drawn. Next, the specifying unit 71 specifies the specified needle tip position SP as the needle tip position in the display image area of the display unit 46. That is, the specifying unit 71 obtains the coordinate value of the needle tip SP of the puncture needle PN (S34).

  Then, the displacement calculator 72 obtains the displacement between the needle tip position SP of the designated puncture needle PN and the center CP of the three-dimensional image based on the volume data (S35). Specifically, as shown in FIGS. 10A and 10B, this displacement is obtained by the coordinate values (x1, y1, z1) of the needle tip SP and the coordinate values (x2, y2, z2) of the center CP of the three-dimensional image. The difference (x2-x1, y2-y1, z2-z1) is obtained.

  Then, the movement amount determination unit 73 cancels the calculated displacement (matches the scan center position SC with the needle tip position SP of the puncture needle), and the bed top plate 33 and the gantry device 10 corresponding to this displacement. The relative movement amount is determined (S36), and a second scan start signal (not shown) including this position information is sent to the scan control unit 41. This relative movement amount is a difference between the actual coordinate value before the movement of the bed top plate 33 and the gantry device 10 and the actual coordinate value after the movement. The information on the amount of movement is sent to the scan control unit 41 as new actual coordinate values of the bed top plate 33 and the gantry device 10 after movement. Below, the case where only the bed top plate 33 is moved based on the determined movement amount will be described.

  The scan control unit 41 sends a movement control signal Si (see FIG. 8) to the bed top plate 33 so as to move the bed top plate 33 by the determined amount of movement. In response to the movement control signal Si, the bed top plate 33 moves up and down, moves back and forth, and / or moves left and right, and moves by the determined amount of movement. Then, the scan control unit 41 causes the subject E to perform an X-ray scan (second scan) (S37).

  The X-ray detection unit 12 detects X-rays exposed to the subject E and acquires the detection data (S38). The detection data detected by the X-ray detection unit 12 is collected by the data collection unit 18 and sent to the processing unit 62 (pre-processing unit 62a).

  The preprocessing unit 62a performs preprocessing on the detection data acquired in S38 and creates projection data (S39). The created projection data is sent to the reconstruction processing unit 62b based on the control of the control unit 48.

  The reconstruction processing unit 62b creates second volume data based on the projection data created in S19 (S40).

  The volume rendering processor 62c creates a second 3D image based on the second volume data created in S40. The created second three-dimensional image (see FIG. 10B) is displayed on the display unit 46 by the display control unit 44 (S41).

  Thereafter, after the puncture is advanced to some extent, the X-ray CT apparatus 1 again scans the subject E with an X-ray scan (first scan) in order to confirm the deviation between the needle tip position SP and the scan center position SC. 3 scans), volume data (third volume data) is created, and the processes from S30 to S41 are repeated.

<Effect>
The X-ray CT apparatus 50 of the present embodiment is an apparatus that creates volume data based on a result of scanning a subject E, which is a target of medical practice using a puncture needle, with X-rays. The X-ray CT apparatus 50 includes a processing unit 62, a specifying unit 71, a displacement calculating unit 72, a scan control unit 41, and a display control unit 44. The processing unit 62 creates a first three-dimensional image in which the puncture needle is drawn based on the first volume data obtained by the first scan. The specifying unit 71 specifies the needle tip position SP of the puncture needle in the first three-dimensional image. The displacement calculator 72 obtains the displacement between the identified needle tip position SP and the center of the first three-dimensional image. The scan control unit 41 shifts the scan center of the first scan so as to cancel this displacement and causes the second scan to be executed. The display control unit 44 causes the display unit 46 to display the second three-dimensional image created by the processing unit 62 based on the second volume data obtained by the second scan.

  Therefore, the needle tip of the puncture needle can always be displayed at the center of the display screen 46a, so that the periphery of the puncture needle can be clearly grasped. For this reason, it is possible to improve the accuracy and efficiency of the puncturing operation.

(Third embodiment)
Next, the configuration of the X-ray CT apparatus 100 according to the third embodiment will be described with reference to FIGS. 12 and 13. The X-ray CT apparatus 100 according to the present embodiment creates a plurality of MPR images based on the volume data, selects an MPR image in which the needle tip of the puncture needle is drawn from the created MPR images, The second scan is executed by shifting the scan center of the first scan so as to cancel the displacement between the needle tip position SP of the puncture needle and the scan center position SC in the MPR image selected via the input means. Is. In addition, since it is the same as that of the above-mentioned 1st Embodiment except the point which added the input part, and the operation | movement of a display control part and an analysis part differing, below, a different point is mainly demonstrated and about the same point, The description may be omitted.

<Overall configuration of X-ray CT apparatus 100>
As shown in FIG. 12, the X-ray CT apparatus 100 includes a gantry device 10, a bed device 30, and a console device 80.

[Console device]
The console device 80 includes a scan control unit 41, a processing unit 42, a display control unit 44, a display unit 46, a control unit 48, an input unit 81, and an analysis unit 90. The input unit 81 is used as an input device for performing various operations on the console device 80. For example, the input unit 81 selects an MPR image on which a puncture needle is drawn from a plurality of MPR images displayed on the display unit, The position of a specific area inside is specified. The input unit 81 includes, for example, a keyboard, a mouse, a trackball, a joystick, and the like. As the input unit 81, a GUI (Graphical User Interface) displayed on the display unit 46 can be used.

  The MPR rendering processing unit 42c generates a plurality of MPR images G1 to G8 (see FIG. 13) described later by rendering the first volume data created (reconstructed) by the reconstruction processing unit 42b in an arbitrary direction. . The plurality of created MPR images G <b> 1 to G <b> 8 are displayed on the display screen 46 a of the display unit 46 by the display control unit 44.

  In the present embodiment, sagittal images as MPR images G1 to G8 are displayed on the display screen 46a of the display screen 46a as shown in FIG. Although FIG. 13 shows an example in which a sagittal image is displayed, an axial image or a coronal image may be displayed. Although FIG. 13 shows an example in which a plurality of sagittal images G1 to G8 are displayed, a plurality of axial images or a plurality of coronal images may be displayed.

  The analysis unit 90 includes a specifying unit 91, a displacement calculation unit 92, and a movement amount determination unit 93. The specifying unit 91 specifies an MPR image selected and instructed by the input unit from among the plurality of MPR images G1 to G8 created by the MPR rendering processing unit 42c. In FIG. 14A, when the MPR image G5 is an MPR image in which a puncture needle is drawn among the plurality of MPR images G1 to G8, when the MPR image G5 is selected by the input unit 81, the specifying unit 91 is selected. The MPR image G5 is designated as the MPR image on which the needle tip is displayed.

  Next, when the needle tip position SP drawn on the MPR image G5 is selected by the input unit 81, the specifying unit 91 specifies the selected position as the needle tip position SP of the puncture needle. Next, the specifying unit 91 specifies the coordinate value at the specified position as the needle tip position SP of the puncture needle in the image area. In this way, the needle tip position SP is manually designated by a selection instruction from the input unit 81.

  The displacement calculation unit 92 obtains the displacement between the position of the needle tip SP of the designated puncture needle PN and the center CP of the MPR image. The movement amount determination unit 93 determines a relative movement amount between the couch top 33 and the gantry device 10 corresponding to the displacement obtained by the displacement calculation unit 92. This amount of movement is obtained by converting the displacement into a displacement in real space coordinates. The above description is based on the premise that the position of the center CP of the MPR image and the position SC of the scan center in the same spatial coordinate system are the same as in the first embodiment.

<Operation>
Hereinafter, the operation of the X-ray CT apparatus 100 according to the present embodiment will be described with reference to FIG. Here, an operation in the case where CT fluoroscopy and puncture are alternately performed and the puncture needle PN is punctured with respect to the target S of the puncture operation will be described.

  In starting the puncture, the X-ray CT apparatus 100 first performs an X-ray scan (first scan) on the subject E to create first volume data.

  Specifically, the X-ray generation unit 11 emits X-rays to the subject E. The X-ray detection unit 12 detects X-rays that have passed through the subject E and acquires the detection data (S50). The detection data detected by the X-ray detection unit 12 is collected by the data collection unit 18 and sent to the processing unit 42 (pre-processing unit 42a).

  The preprocessing unit 42a performs preprocessing on the detection data acquired in S50 and creates projection data (S51). The created projection data is sent to the reconstruction processing unit 42b based on the control of the control unit 48.

  The reconstruction processing unit 42b creates a plurality of tomographic image data based on the projection data created in S51. Next, the reconstruction processing unit 42b creates first volume data by interpolating a plurality of tomographic image data (S52).

  The MPR rendering processing unit 42c creates a plurality of MPR images G1 to G8 by rendering the first volume data created (reconstructed) by the reconstruction processing unit 42b in an arbitrary direction. In the example of FIG. 13, sagittal images are displayed as MPR images G1 to G8 (S53).

  In the present embodiment, an example in which a plurality of MPR images G1 to G8 are sequentially displayed on the display screen 46a of the display unit 46 has been described. Specifically, the display control unit 44 sequentially switches and displays the plurality of MPR images G1 to G8. Further, for example, after displaying only the MPR image G1, the display control unit 44 displays another MPR image in response to a selection instruction via a switching display (changeover switch, switching scroll bar) displayed on a part of the display screen 46a. G2 to G8 may be switched and displayed in order.

  The user operates the input unit 81 to select the first MPR image G5 on which the puncture needle is drawn from the plurality of MPR images G1 to G8 displayed on the display unit 46. The specifying unit 91 designates the first MPR image G5 including the needle tip of the puncture needle from the first MPR image G5 selected by the input unit 81 (see S54, FIG. 14B).

  Next, the specifying unit 91 obtains the coordinate value of the needle tip of the puncture needle (S55).

  Then, the displacement calculation unit 92 calculates the displacement between the calculated coordinate values (X1, Y1, Z1) of the puncture needle and the scan center positions (X2, Y2, Z2) (S56).

  Then, the movement amount determination unit 93 cancels the calculated displacement (matches the scan center position with the needle tip position SP of the puncture needle) between the bed top plate 33 and the gantry device 10 corresponding to this displacement. A relative movement amount is determined (S57), and a second scan start signal (not shown) including this position information is sent to the scan control unit 41. This relative movement amount is a difference between the actual coordinate value before the movement of the bed top plate 33 and the gantry device 10 and the actual coordinate value after the movement. The information on the amount of movement is sent to the scan control unit 41 as new actual coordinate values of the bed top plate 33 and the gantry device 10 after movement.

  As a type of relative movement of the couch top 33 and the gantry device 10, the case where only the couch top 33 is moved, the case where only the gantry device 10 is moved, and both the couch top plate 33 and the gantry device 10 are moved. There are cases. Below, the case where only the bed top plate 33 is moved based on the determined movement amount will be described.

  The scan control unit 41 sends a movement control signal Si (see FIG. 12) to the bed top plate 33 so as to move the bed top plate 33 by the determined amount of movement. In response to the movement control signal Si, the bed top plate 33 moves up and down, moves back and forth, and / or moves left and right, and moves by the determined amount of movement. Then, the scan control unit 41 causes the subject E to perform an X-ray scan (second scan) (S58).

  The X-ray detection unit 12 detects X-rays exposed to the subject E, and acquires the detection data (S59). Detection data detected by the X-ray detection unit 12 is collected by the data collection unit 18 and sent to the processing unit 42 (pre-processing unit 42a).

  The preprocessing unit 42a performs preprocessing on the detection data acquired in S18 and creates projection data (S60). The created projection data is sent to the reconstruction processing unit 42b based on the control of the control unit 48.

  The reconstruction processing unit 42b creates a plurality of tomographic image data based on the projection data created in S19. Further, the reconstruction processing unit 42b creates second volume data by performing interpolation processing on a plurality of tomographic image data (S61).

  The MPR rendering processor 42c creates a plurality of MPR images by rendering the second volume data created in S61 in an arbitrary direction. Next, the specifying unit 91 specifies a second MPR image G5 ′ corresponding to the first MPR image G5 from among the plurality of MPR images. The display control unit 44 displays the designated second MPR image G5 ′ on the display screen 46a of the display unit 46 (see S62, FIG. 14C). As shown in FIG. 14C, the needle tip position SP of the puncture needle and the scan center position SC in the second MPR image G5 ′ coincide.

  Thereafter, the X-ray CT apparatus 1 again scans the subject E with an X-ray scan (third) in order to confirm the deviation between the needle tip position SP of the puncture needle and the scan center position after the puncture has been advanced to some extent. Scan) to create volume data (third volume data), and the processes from S10 to S21 are repeated.

<Effect>
The X-ray CT apparatus 100 of the present embodiment is an apparatus that creates volume data based on a result of scanning a subject E, which is a target of medical practice using a puncture needle PN, with X-rays. The X-ray CT apparatus 100 includes an MPR rendering processing unit 42c, a display control unit 44, a specifying unit 91, and a displacement calculating unit 92. The MPR rendering processor 42c creates a plurality of MPR images based on the first volume data obtained by the first scan. The display control unit 44 switches and displays a plurality of MPR images. The input unit 81 selects a first MPR image in which a puncture needle PN is drawn from a plurality of MPR images according to an operation. The specifying unit 91 specifies the needle tip position SP of the puncture needle PN in the first MPR image that specifies the needle tip position SP of the puncture needle PN in the first MPR image selected according to the operation from the plurality of MPR images. The displacement calculation unit 92 obtains the displacement between the identified needle tip position SP and the center of the first MPR image. The scan control unit 41 shifts the scan center of the first scan so as to cancel the displacement between the needle tip position SP and the center of the first MPR image, and causes the second scan to be executed. The display control unit 44 causes the display unit 46 to display the second MPR image in the same cross section as the first MPR image, which is created by the MPR rendering processing unit 42c based on the second volume data obtained by the second scan.

  Accordingly, as shown in FIG. 14C, the needle tip SP of the puncture needle PN can always be displayed at the center of the display screen 46a, so that the periphery of the puncture needle PN can be clearly grasped. In addition, an MPR image on which a puncture needle is drawn can be selected from a plurality of MPR images while switching the display on the screen, and the needle tip position SP can also be confirmed and identified on the screen. For this reason, the accuracy and efficiency of the puncturing operation can be improved, and the degree of freedom of screen selection can be improved.

  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 1,50,100 X-ray CT apparatus 10 Base apparatus 11 X-ray generation part 12 X-ray detection part 13 Rotating body 13a Opening part 14 High voltage generation part 15 Base drive part 16 X-ray aperture part 18 Data collection part 19 Aperture drive part DESCRIPTION OF SYMBOLS 30 Bed apparatus 31 Bed 32 Bed drive part 33 Bed top plate 34 Base 40 Console apparatus 41 Scan control part 42,62 Processing unit 42a, 62a Pre-processing part 42b, 62b Reconstruction processing part 42c MPR rendering processing part (MPR processing part) )
44 Display control unit 45, 70 Analysis unit 46 Display unit 48 Control unit 51, 71 Identification unit 52, 72 Displacement calculation unit 53, 73 Movement amount determination unit

Claims (2)

An X-ray CT apparatus for creating volume data based on a result of scanning a subject into which a puncture needle has been inserted with X-rays,
A display control unit for displaying a plurality of MPR images created based on the first volume data obtained by the first scan;
An input section;
A specifying unit for specifying the needle tip position of the puncture needle in the first MPR image selected by the input unit among the displayed plurality of MPR images ;
A scan controller that shifts the scan center of the first scan based on the identified needle tip position and the center of the first MPR image , and executes the second scan,
The X-ray CT apparatus, wherein the display control unit causes the display unit to display a second MPR image created based on the second volume data obtained by the second scan. A top plate on which the subject is placed;
A gantry device for performing the scan;
A movement amount determination unit for determining a relative movement amount between the top plate and the gantry device based on the displacement;
The X-ray CT apparatus according to claim 1, wherein the scan control unit controls movement of at least one of the top plate and the gantry device according to the determined movement amount.

Images