JP2013154161A - X-ray ct apparatus - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a technology which enables a preset image to be easily recognized on an image obtained at this time.SOLUTION: An X-ray CT apparatus produces volume data on the basis of on the basis of the result of scanning a subject body by means of x-rays in the state of being inserted with a puncture needle. The X-ray CT apparatus has a processing section and an image processing section. The processing section identifies the puncture needle position in the volume data. The image processing section creates the image of a cross-section including the puncture needle.

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 irradiates the subject a plurality of times from different directions along a circular orbit centered on the subject. The X-ray CT apparatus collects a plurality of detection data by detecting X-rays transmitted through a subject with an X-ray detector. 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. Hereinafter, a cross-sectional image displayed in MPR by rendering volume data may be referred to as an “MPR image”. The 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 a coronal image showing a cross section of the subject along the body axis. There is. Furthermore, an arbitrary cross-sectional image (oblique image) in the volume data is also included in the MPR image. The plurality of created MPR images can be simultaneously displayed on a display unit or the like.

  There is an imaging method called CT fluoroscopy (CTF) that is performed using an X-ray CT apparatus. CT fluoroscopy is an imaging method in which an image relating to a region of interest of a subject is obtained in real time by continuously irradiating the subject with X-rays. In CT fluoroscopy, images are created in real time by reducing the detection data collection rate and reducing the time required for reconstruction processing. CT fluoroscopy is used, for example, for confirming the positional relationship between the tip of a puncture needle and a part from which a specimen is collected during a biopsy, or for confirming the position of a tube when performing a drainage method. The drainage method is a method of draining the body fluid accumulated in the body cavity with a tube or the like.

  When performing a biopsy on a subject while referring to an MPR image based on volume data obtained by CT fluoroscopy, for example, scanning and puncturing may be performed alternately. 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 advances the puncture. By repeatedly performing this operation until the biopsy is completed, the biopsy can be reliably performed.

  Moreover, when performing a biopsy by CT fluoroscopy, a puncture plan may be created in advance. The puncture plan is information including a preset insertion path of the puncture needle to the subject (hereinafter sometimes referred to as “planned path”). The puncture plan is set, for example, by drawing a planned route by inputting an instruction from a mouse or the like in a CT image acquired in advance before performing CT fluoroscopy. A doctor or the like punctures a subject while referring to a CT image showing a planned route and an MPR image based on volume data obtained by X-ray scanning each time.

JP 2002-112998 A

  By the way, an image (for example, a planned route) set in a CT image acquired in advance is not displayed on an image based on volume data obtained each time by X-ray scanning.

  The embodiment has been made to solve the above-described problems, and an object thereof is to provide a technique capable of easily recognizing a preset image on an image obtained at the present time. .

  The X-ray CT apparatus of the embodiment is an X-ray CT apparatus that creates volume data based on a result of scanning a subject with a puncture needle inserted with X-rays. The X-ray CT apparatus has a processing unit and an image processing unit. The processing unit specifies the position of the puncture needle in the volume data. The image processing unit creates an image of a cross section including the puncture needle.

1 is a block diagram of an X-ray CT apparatus according to a first embodiment. It is a figure which supplements description of the setting part which concerns on 1st Embodiment. It is a figure which supplements description of the setting part which concerns on 1st Embodiment. 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 figure which supplements description of the setting part which concerns on 2nd Embodiment. It is a figure which supplements description of the setting part which concerns on 2nd Embodiment. It is a flowchart which shows the outline | summary of operation | movement of the X-ray CT apparatus which concerns on 2nd Embodiment.

(First embodiment)
The configuration of the X-ray CT apparatus 1 according to the first embodiment will be described with reference to FIGS. 1 to 3. Since “image” and “image data” have a one-to-one correspondence, in the present embodiment, they may be regarded as the same.

<Device configuration>
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]
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 diaphragm driver 17, And a data collection unit 18.

  The X-ray generator 11 includes an X-ray tube that generates X-rays (for example, a vacuum tube that generates a cone-shaped or pyramid-shaped X-ray beam, not shown). The X-ray generator 11 exposes the generated X-rays 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-rays that have passed through the subject E. Specifically, 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. 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. That is, the X-ray generation unit 11 and the X-ray detection unit 12 are provided so as to be rotatable along a circular orbit centered on the subject E.

  The high voltage generator 14 applies a high voltage to the X-ray generator 11 (hereinafter, “voltage” means the voltage between the anode and the cathode in the X-ray tube). The X-ray generator 11 generates X-rays based on the high voltage.

  The gantry driving unit 15 drives the rotating body 13 to rotate. 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 17 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 collecting unit 18 transmits the detection data converted into the digital signal to the console device 40. In addition, when performing CT fluoroscopy, the data collection part 18 shortens the collection rate of detection data.

[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 can be moved by the couch driving unit 32 in the body axis direction of the subject E and in the direction perpendicular to the body axis direction. That is, the bed driving unit 32 can insert and remove the bed top plate 33 on which the subject E is placed with respect to the opening 13 a of the rotating body 13. The base 34 can move the bed top 33 in the vertical direction (a direction perpendicular to the body axis direction of the subject E) by the bed driving unit 32.

[Console device]
The console device 40 is used for operation input to the X-ray CT apparatus 1. 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 processing unit 41, a setting unit 42, a storage unit 43, a display control unit 44, a display unit 45, a scan control unit 46, and a control unit 47.

  The processing unit 41 executes various processes on the detection data transmitted from the gantry device 10 (data collection unit 18). The processing unit 41 includes a preprocessing unit 41a, a reconstruction processing unit 41b, and a rendering processing unit 41c.

  The pre-processing unit 41a performs pre-processing such as logarithmic conversion processing, offset correction, sensitivity correction, and beam hardening correction on detection data detected by the gantry device 10 (X-ray detection unit 12) to create projection data. To do.

  The reconstruction processing unit 41b creates CT image data (tomographic image data and volume data) based on the projection data created by the preprocessing unit 41a. 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. Further, when performing CT fluoroscopy, since the collection rate of the detection data is shortened, the reconstruction time by the reconstruction processing unit 41b is shortened. Therefore, real-time CT image data corresponding to scanning can be created.

  The rendering processor 41c performs a rendering process on the volume data created by the reconstruction processor 41b. The rendering processing unit 41c includes a first image processing unit 411c and a second image processing unit 412c.

  The first image processing unit 411c creates a pseudo three-dimensional image (image data) based on the volume data. The “pseudo three-dimensional image” is an image for displaying the three-dimensional structure of the subject E two-dimensionally. As a specific example, the first image processing unit 411c creates a pseudo three-dimensional image that is a display image (image data) by performing volume rendering processing on the volume data created by the reconstruction processing unit 41b. To do.

  The second image processing unit 412c creates an MPR image (image data) based on the volume data. The “MPR image” is an image showing a desired cross section of the subject E. The MPR image includes an axial image, a sagittal image, and a coronal image that are three orthogonal cross sections. Alternatively, the second image processing unit 412c may create an oblique image indicating an arbitrary cross section as an MPR image. As a specific example, the second image processing unit 412c creates an MPR image by performing rendering processing in a desired direction on the volume data created by the reconstruction processing unit 41b.

  The setting unit 42 sets a predetermined setting image for the image based on the volume data. A “setting image” is a desired image drawn on an image based on volume data. For example, when a biopsy is performed on the subject E, the plan of the insertion path of the puncture needle (which route is used to insert the puncture needle, that is, the planned path) may be drawn on the image in advance. . The drawn image (plan route image) is an example of a setting image. Alternatively, a marking image in which the position of an attention site (lesioned part or the like) in the image is surrounded by a circle or an ellipse can be used as the setting image. The display control unit 44 displays the set setting image on an image based on the volume data. The image based on the volume data on which the setting image is displayed can be used as a reference image when puncturing the subject E or the like.

  As a specific example of the setting unit 42, an image (setting image) indicating a planned path with respect to a pseudo three-dimensional image based on volume data (first volume data) obtained by scanning (first scanning) performed at a certain timing. The case of setting is described. The cube shown in FIGS. 2A and 2B schematically shows a pseudo three-dimensional image D based on volume data. Here, it is assumed that each surface of the cube indicates the body surface of the subject E. The display control unit 44 causes the display unit 45 to display the pseudo 3D image D.

  The surgeon uses the input device provided in the X-ray CT apparatus 1 or the like for the pseudo three-dimensional image D displayed on the display unit 45 to perform the position S of the target site (lesion site or the like). And two points of the insertion position P of the puncture needle on the body surface are designated (see FIG. 2A). The setting unit 42 calculates the shortest distance L connecting the two points, and sets a line segment connecting the shortest distances L as the setting image I. The display control unit 44 displays the set image I that has been set on the pseudo three-dimensional image (see FIG. 2B). Further, the setting unit 42 obtains the position of the setting image I in the volume data (coordinate values; hereinafter, sometimes referred to as “setting position”). The setting image I and the setting position are stored in the storage unit 43.

  The surgeon can directly draw a line segment indicating the planned route on the pseudo three-dimensional image using an input device or the like. In this case, the setting unit 42 sets the drawn line segment as the setting image I. Alternatively, the setting unit 42 calculates the position of the lesioned part and the position of the body surface closest to the lesioned part by performing image analysis processing such as a region growing method on the volume data. And the setting part 42 can also calculate the line segment which connects them, and can also set the said line segment as the setting image I.

  The memory | storage part 43 is comprised by semiconductor memory devices, such as RAM and ROM. The storage unit 43 stores detection data, projection data, CT image data after reconstruction processing, and the like in addition to the setting image and the setting position of the setting image.

  The display control unit 44 performs various controls related to image display. For example, a pseudo three-dimensional image created by the first image processing unit 411c, an MPR image (axial image, sagittal image, coronal image, oblique image) created by the second image processing unit 412c, etc. are displayed on the display unit 45. To control.

  In the present embodiment, the display control unit 44 displays the setting image at a position corresponding to the setting position in the image based on the volume data displayed on the display unit 45.

  As a specific example of the display control unit 44, a pseudo three-dimensional image based on volume data (second volume data) obtained by a scan (second scan) performed at a timing different from the first scan is displayed on the display unit 45. The case where it is made to describe is described. In the present embodiment, the first volume data and the second volume data are assumed to have the same number of tomographic image data and the number of pixels of the image. In addition, the imaging conditions of the first scan and the second scan (imaging position, rotation speed of the rotating body 13, etc.) are also assumed to be equal. That is, it is assumed that the first volume data and the second volume data are in the same coordinate system.

  In this case, the display control unit 44 displays the same image as the set image at a position corresponding to the set position stored in the storage unit 43. As a display mode of the setting image, the display control unit 44 can replace the pixel (pixel value) in the pseudo three-dimensional image based on the second volume data with the pixel (pixel value) of the setting image. Alternatively, the display control unit 44 can superimpose the setting image on the pseudo three-dimensional image based on the second volume data. An image based on the second volume data on which the setting image is displayed can be used as a new reference image.

  The display unit 45 includes an arbitrary display device such as an LCD (Liquid Crystal Display) or a CRT (Cathode Ray Tube) display. For example, the display unit 45 displays an MPR image obtained by rendering volume data.

  The scan control unit 46 controls various operations related to the X-ray scan. For example, the scan control unit 46 controls the high voltage generation unit 14 to apply a high voltage to the X-ray generation unit 11. The scan control unit 46 controls the gantry driving unit 15 to rotationally drive the rotating body 13. The scan control unit 46 controls the aperture driving unit 17 to operate the X-ray aperture unit 16. The scan control unit 46 controls the bed driving unit 32 to move the bed 31.

  The control unit 47 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 47 controls the scan control unit 46 to cause the gantry device 10 to perform a preliminary scan and a main scan and collect detection data. In addition, the control unit 47 controls the processing unit 41 to perform various types of processing (preprocessing, reconstruction processing, etc.) on the detected data. Alternatively, the control unit 47 controls the display control unit 44 to display an image based on the CT image data stored in the storage unit 43 on the display unit 45.

<Operation>
Next, the operation of the X-ray CT apparatus 1 according to the present embodiment will be described with reference to FIG. Here, the operation when a biopsy is performed using CT fluoroscopy after creating a planned path for the puncture needle will be described.

  Before starting a biopsy, the X-ray CT apparatus 1 first performs X-ray scan (first scan) on the subject E to create volume data (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 (S10). Detection data detected by the X-ray detection unit 12 is collected by the data collection unit 18 and sent to the processing unit 41 (pre-processing unit 41a).

  The pre-processing unit 41a performs pre-processing such as logarithmic conversion processing, offset correction, sensitivity correction, and beam hardening correction on the detection data acquired in S10, and creates projection data (S11). The created projection data is sent to the reconstruction processing unit 41b based on the control of the control unit 47.

  The reconstruction processing unit 41b creates a plurality of tomographic image data based on the projection data created in S11. The reconstruction processing unit 41b creates first volume data by performing interpolation processing on a plurality of tomographic image data (S12).

  The first image processing unit 411c creates a pseudo three-dimensional image by rendering the first volume data created in S12. The display control unit 44 displays the created pseudo 3D image on the display unit 45 (S13).

  While referring to the pseudo three-dimensional image displayed on the display unit 45, the surgeon makes a plan of the insertion path of the puncture needle (planned path). The operator designates the position of the lesion in the pseudo three-dimensional image and the insertion position of the puncture needle using an input device or the like. The setting unit 42 sets a line segment connecting the designated positions as a setting image (S14). The display control unit 44 displays the set setting image on the pseudo three-dimensional image. The setting unit 42 sends the setting image and the coordinate value (setting position) of the setting image to the storage unit 43. The storage unit 43 stores the setting image and the coordinate value (setting position) (S15).

  Thereafter, the surgeon starts biopsy of the subject E while referring to the pseudo three-dimensional image showing the setting image.

  After a certain amount of biopsy (after inserting the puncture needle into the subject E), the X-ray CT apparatus 1 is used to confirm the puncture state (whether the puncture needle is traveling along the planned path, etc.). Performs an X-ray scan (second scan) on the subject E again to create volume data (second volume data).

  That is, as in the first scan, 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 (S16). As described above, the imaging conditions for the first scan and the second scan are the same.

  The preprocessing unit 41a performs preprocessing on the detection data acquired in S16 and creates projection data (S17). The reconstruction processing unit 41b creates second volume data by interpolating a plurality of tomographic image data created based on the projection data created in S17 (S18). The first image processing unit 411c creates a pseudo three-dimensional image by rendering the second volume data created in S18 (S19).

  The display control unit 44 causes the display unit 45 to display the pseudo 3D image created in S19, and sets the position corresponding to the setting position stored in S15 in the pseudo 3D image based on the second volume data in S14. The same image as the set image is displayed (S20).

  As described above, by displaying a setting image (an image showing a planned route) drawn in advance before the start of the biopsy with respect to the image based on the second volume data, the volume data (first volume) in which the setting image is set The setting image can be easily grasped even in an image based on volume data (second volume data) different from (data). In addition, when the puncture needle is displaced from the planned route as a result of the biopsy, the position of the puncture needle displayed in the image based on the volume data and the setting image displayed in the image are displayed in a shifted state. Is done. Conversely, when the puncture needle is inserted along the planned route, the position of the puncture needle displayed in the image based on the volume data is displayed in a state where the setting image displayed in the image overlaps. . That is, by referring to the image on which the setting image is displayed, the surgeon can easily grasp the puncture needle displacement (deviation from the planned route).

  The processing unit 41, the setting unit 42, the display control unit 44, the scan control unit 46, and the control unit 47 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 processing program for executing the function of the processing unit 41. The storage device also stores a setting unit processing program for executing the function of the setting unit 42. Further, the storage device stores a display control program for executing the function of the display control unit 44. Further, the storage device stores a scan control program for executing the function of the scan control unit 46. The storage device stores a control program for executing the function of the control unit 47. A processing device such as a CPU executes the functions of each unit by executing each program stored in the storage device.

  The configuration and operation of the single X-ray CT apparatus 1 have been described so far. On the other hand, the configuration of the present embodiment can be realized as an X-ray CT system including the X-ray CT apparatus 1.

  For example, the X-ray CT apparatus 1 sets a setting image for an image based on volume data created in advance, and stores the setting image and the setting position of the setting image. Then, a biopsy using CT fluoroscopy is performed with another X-ray CT apparatus. In this case, another X-ray CT apparatus displays an image based on the second volume data obtained by CT fluoroscopy on the display unit. Further, the other X-ray CT apparatus reads the stored setting image and the setting position of the setting image from the X-ray CT apparatus 1, and sets the setting image at a position corresponding to the setting position of the setting image in the image based on the second volume data. Display an image.

  Alternatively, the X-ray CT apparatus 1 creates an image based on the first volume data. A computer provided separately from the X-ray CT apparatus 1 sets a setting image for an image based on the first volume data, and stores the setting image and the setting position of the setting image. When performing CT fluoroscopy with the X-ray CT apparatus 1 (or another X-ray CT apparatus), the X-ray CT apparatus 1 displays an image based on the second volume data obtained by CT fluoroscopy on the display unit. Let Further, the X-ray CT apparatus 1 reads the stored setting image and the setting position of the setting image from the computer, and displays the setting image at a position corresponding to the setting position of the setting image in the image based on the second volume data. Is also possible.

<Action and effect>
The operation and effect of this embodiment will be described.

  The X-ray CT apparatus 1 of the present embodiment creates first volume data and second volume data based on the results of scanning a subject with X-rays at different timings. The X-ray CT apparatus 1 includes a setting unit 42, a storage unit 43, and a display control unit 44. The setting unit 42 sets a predetermined setting image for the image based on the first volume data. The storage unit 43 stores the setting image and the setting position of the setting image. The display control unit 44 causes the display unit 45 to display an image based on the second volume data, and causes the setting image to be displayed at a position corresponding to the setting position in the image based on the second volume data.

  Specifically, the X-ray CT apparatus 1 includes a first image processing unit 411c. The first image processing unit 411c creates a pseudo three-dimensional image that two-dimensionally shows the three-dimensional structure of the subject E based on the volume data. The setting unit 42 sets a setting image for the pseudo three-dimensional image based on the first volume data. The display control unit 44 causes the display unit 45 to display the pseudo three-dimensional image based on the second volume data, and displays the setting image at a position corresponding to the setting position in the pseudo three-dimensional image based on the second volume data.

  In addition, the configuration of the present embodiment can be realized as an X-ray CT system. The X-ray CT system includes at least one X-ray CT apparatus, a setting unit 42, a storage unit 43, and a display control unit 44. The X-ray CT apparatus creates volume data based on the result of scanning the subject E with X-rays. The setting unit 42 sets a predetermined setting image for an image based on first volume data created in advance. The storage unit 43 stores the setting image and the setting position of the setting image. The display control unit 44 causes the display unit 45 to display an image based on the newly created second volume data, and causes the setting image to be displayed at a position corresponding to the setting position in the image based on the second volume data.

  In this way, the display control unit 44 causes the setting image set for the pseudo three-dimensional image based on the first volume data to be displayed at a position corresponding to the setting position in the pseudo three-dimensional image based on the second volume data. Can do. For example, in a biopsy using CT fluoroscopy, the display control unit 44 also displays an image showing a preset planned route in a pseudo three-dimensional image based on volume data (second volume data) obtained each time by X-ray scanning. Can be displayed at the same position. Therefore, by referring to the pseudo three-dimensional image, the operator can confirm the planned route in the current image. Further, when the puncture needle is displayed in the image based on the second volume data, the puncture needle Therefore, it is possible to easily grasp whether the puncture needle is moving along the planned route. That is, according to the present embodiment, it is possible to easily recognize a preset image (set image) on the image obtained at the current time.

(Second Embodiment)
The configuration of the X-ray CT apparatus 1 according to the second embodiment will be described with reference to FIGS. 4A to 5. In the present embodiment, the setting unit 42 sets a setting image for the MPR image based on the first volume data. A configuration in which the display control unit 44 displays the setting image on the MPR image based on the second volume data will be described. Detailed description of the same configuration as that of the first embodiment will be omitted. In the following description, an axial image is used as an example of an MPR image, but the configuration of the present embodiment can be similarly applied to a sagittal image or a coronal image.

  The setting unit 42 in the present embodiment sets a predetermined setting image for the MPR image based on the volume data. The MPR image is created by the second image processing unit 412c.

  As a specific example of the setting unit 42, an image (setting image) indicating a planned path of the puncture needle with respect to an axial image based on volume data (first volume data) obtained by scanning (first scanning) performed at a certain timing. ) Is described. 4A and 4B show an axial image AI based on volume data. The display control unit 44 displays the axial image AI on the display unit 45.

  For the axial image AI displayed on the display unit 45, the surgeon selects 2 of the position S of the target site (lesion site or the like) where biopsy is performed using an input device or the like, and the insertion position P of the puncture needle on the body surface. A point is designated (see FIG. 4A). The setting unit 42 calculates the shortest distance L connecting the two points, and sets a line segment connecting the shortest distances L as the setting image I. The display control unit 44 displays the set setting image I on the axial image AI (see FIG. 4B). The setting unit 42 obtains a set position (coordinate value) in the axial image AI. The setting image I and the setting position are stored in the storage unit 43. The axial image AI is an image based on three-dimensional volume data. Therefore, the position of the setting image set in the axial image AI can be specified by a three-dimensional coordinate value.

  In the present embodiment, the display control unit 44 displays the setting image at a position corresponding to the setting position in the MPR image based on the volume data displayed on the display unit 45.

  As a specific example of the display control unit 44, an axial image based on volume data (second volume data) obtained by a scan (second scan) performed at a timing different from the first scan is displayed on the display unit 45. Is described. Note that the axial image based on the first volume data and the axial image based on the second volume data show cross sections at the same position in the body axis direction.

  In this case, the display control unit 44 displays the same image as the set image at a position in the axial image corresponding to the set position stored in the storage unit 43.

  Alternatively, as the processing of the display control unit 44, as in the first embodiment, the same image as the setting image may be displayed at a position corresponding to the setting position in the pseudo three-dimensional image based on the second volume data. As described above, the setting position set for the MPR image (axial image) based on the first volume data has a three-dimensional coordinate value. Therefore, even if the image based on the second volume data is a pseudo three-dimensional image, the position corresponding to the set position can be specified.

<Operation>
Next, the operation of the X-ray CT apparatus 1 according to the present embodiment will be described with reference to FIG. Here, an operation when a biopsy is performed using CT fluoroscopy after creating a planned path for the puncture needle in the axial image will be described.

  Before starting a biopsy, the X-ray CT apparatus 1 first performs X-ray scan (first scan) on the subject E to create volume data (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). The preprocessing unit 41a performs preprocessing such as logarithmic conversion processing, offset correction, sensitivity correction, and beam hardening correction on the detection data acquired in S30, and creates projection data (S31). The reconstruction processing unit 41b creates a plurality of tomographic image data based on the projection data created in S31. Further, the reconstruction processing unit 41b creates first volume data by interpolating a plurality of tomographic image data (S32).

  The second image processing unit 412c creates an axial image by rendering the first volume data created in S32. The display control unit 44 displays the created axial image on the display unit 45 (S33).

  While referring to the axial image displayed on the display unit 45, the surgeon makes a plan of the insertion path of the puncture needle (planned path). The operator designates the position of the lesion in the axial image and the insertion position of the puncture needle using an input device or the like. The setting unit 42 sets a line segment connecting the designated positions as a setting image (S34). The display control unit 44 displays the set setting image on the axial image. The setting unit 42 sends the coordinate value (setting position) of the setting image to the storage unit 43. The storage unit 43 stores the setting image and the coordinate value (setting position) of the setting image (S35).

  Thereafter, the surgeon advances the puncture to the subject E while referring to the axial image showing the setting image.

  After a certain amount of biopsy (after inserting the puncture needle into the subject E), the X-ray CT apparatus 1 is used to confirm the puncture state (whether the puncture needle is traveling along the planned path, etc.). Performs an X-ray scan (second scan) on the subject E again to create volume data (second volume data).

  That is, as in the first scan, 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 (S36). As in the first embodiment, the imaging conditions for the first scan and the second scan are the same.

  The preprocessing unit 41a performs preprocessing on the detection data acquired in S36 and creates projection data (S37). The reconstruction processing unit 41b creates second volume data by interpolating a plurality of tomographic image data created based on the projection data created in S37 (S38). The second image processing unit 412c creates an axial image by rendering the second volume data (S39).

  The display control unit 44 causes the display unit 45 to display the axial image created in S39 and sets the setting image set in S34 at a position corresponding to the setting position stored in S35 in the axial image based on the second volume data. The same image is displayed (S40).

<Action and effect>
The operation and effect of this embodiment will be described.

  The X-ray CT apparatus 1 of the present embodiment includes a second image processing unit 412c. The second image processing unit 412c creates an MPR image showing a cross section of the subject E based on the volume data. The setting unit 42 sets a setting image for the MPR image based on the first volume data. The display control unit 44 displays the MPR image based on the second volume data on the display unit 45 and displays the setting image at a position corresponding to the setting position in the MPR image based on the second volume data.

  In addition, the X-ray CT apparatus 1 of the present embodiment includes a first image processing unit 411c and a second image processing unit 412c. The first image processing unit 411c creates a pseudo three-dimensional image that two-dimensionally shows the three-dimensional structure of the subject E based on the volume data. The second image processing unit 412c creates an MPR image showing a cross section of the subject E based on the volume data. The setting unit 42 sets a setting image for the MPR image based on the first volume data. The display control unit 44 causes the display unit 45 to display the pseudo three-dimensional image based on the second volume data, and displays the setting image at a position corresponding to the setting position in the pseudo three-dimensional image based on the second volume data.

  Further, the second image processing unit 412c in the X-ray CT apparatus 1 of the present embodiment creates at least one of an axial image, a sagittal image, a coronal image, and an oblique image of the subject E as an MPR image.

  As described above, the display control unit 44 sets the setting image set for the MPR image based on the first volume data to a position corresponding to the setting position in the image (pseudo three-dimensional image or MPR image) based on the second volume data. Can be displayed. For example, in a biopsy using CT fluoroscopy, the display control unit 44 displays an image showing a preset planned route at the same position in an image based on volume data (second volume data) obtained each time by X-ray scanning. Can be displayed. Therefore, by referring to this image, the operator can confirm the planned route in the current image. Furthermore, when the puncture needle is displayed in the image based on the second volume data, the puncture needle and the planned route are displayed. Therefore, it is possible to easily grasp whether the puncture needle is moving along the planned route. That is, according to the present embodiment, it is possible to easily recognize a preset image (set image) on the image obtained at the current time. Further, the setting image can be easily set with an MPR image which is a two-dimensional image.

(Modification 1)
In the second embodiment, a setting image is set for an axial image. Here, since the setting image is set from an image based on volume data, it has a three-dimensional coordinate value. Therefore, the setting unit 42 can automatically set a setting image at a position corresponding to the three-dimensional coordinate value in a coronal image or a sagittal image created from volume data that is a source of an axial image.

  That is, the setting unit 42 may set a setting image for an MPR image showing a certain cross section, and set a setting image for an MPR image showing another cross section based on the setting position of the setting image. it can. The display control unit 44 displays the set setting image on each MPR image.

(Modification 2)
By observing a cross-sectional image along the image (setting image) indicating the planned path of the puncture needle set by the setting unit 42, the operator can grasp the entire planned path on a two-dimensional image. Become. In this case, the second image processing unit 412c creates an oblique image of a cross section along the setting image based on the first volume data.

  Further, the second image processing unit 412c can store the cross-sectional position of the oblique image of the cross section along the setting image, and can create the oblique image of the same cross section in the second volume data. That is, the second image processing unit 412c always creates an oblique image at the same cross-sectional position in each of the volume data (first to nth volume data) obtained at different timings. Each oblique image created is displayed on the display unit 45 by the display control unit 44.

  Here, for example, when the puncture needle does not travel along the planned route, the puncture needle is not displayed in the oblique image based on the second volume data. Therefore, the surgeon can easily grasp the puncture needle displacement (deviation from the planned route). Note that the image created by the second image processing unit 412c is not limited to the oblique image, but may be an image of a cross section along the setting image. For example, when an insertion path is planned perpendicular to the body axis direction of the subject E, the image created by the second image processing unit 412c is preferably an axial image.

(Modification 3)
In addition, after performing a biopsy on the subject E, there is a case where it is desired to confirm a path (the path through which the puncture needle is inserted) in which the puncture needle has actually traveled. In this case, it is desirable to create and store a cross section including the puncture needle in each of the volume data (first to nth volume data) obtained at different timings.

  Therefore, in this modification, a configuration in which the position of the puncture needle is detected in each volume data and a new image is created with a cross section including the puncture needle will be described. Hereinafter, an example of creating an oblique image as a new image will be described.

  For example, the processing unit 41 specifies the position of the puncture needle for each of the plurality of volume data. As a specific example, the processing unit 41 calculates a difference between tomographic image data constituting volume data for each of a plurality of volume data, and identifies tomographic image data having a large difference. Then, the processing unit 41 performs image processing such as edge detection on the specified tomographic image data, and specifies the position of the puncture needle. Note that the method of specifying the position of the puncture needle in the volume data is not limited to the above method, and a known method can be used.

  The second image processing unit 412c creates an oblique image that is a cross section including the puncture needle by rendering the volume data in a predetermined direction with the specified position of the puncture needle as a reference. The second image processing unit 412c performs this process for each of the plurality of volume data. Therefore, the puncture needle is always displayed on the oblique image created by the second image processing unit 412c. The oblique image created by the second image processing unit 412 c is stored in the storage unit 43. Therefore, after the biopsy is completed, the surgeon observes a plurality of oblique images stored in the storage unit 43, so that the path along which the puncture needle has advanced (how the puncture needle has been inserted) It can be confirmed again.

<Effects common to the embodiments>
According to the X-ray CT apparatus of at least one embodiment described above, the display control unit corresponds to the setting position in the image based on the second volume data, the setting image set for the image based on the first volume data. Can be displayed in the position. That is, according to the present embodiment, it is possible to easily recognize a preset image (set image) on the image obtained at the current time.

  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 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 17 Aperture drive part 18 Data collection part 30 Bed apparatus 32 Bed driving unit 33 Bed top plate 34 Base 40 Console device 41 Processing unit 41a Preprocessing unit 41b Reconstruction processing unit 41c Rendering processing unit 411c First image processing unit 412c Second image processing unit 42 Setting unit 43 Storage unit 44 Display control Unit 45 display unit 46 scan control unit 47 control unit E subject

Claims (7)

An X-ray CT apparatus for creating volume data based on a result of scanning a subject with a puncture needle inserted by X-ray,
A processing unit for specifying the position of the puncture needle in the volume data;
An image processing unit for creating an image of a cross section including the puncture needle;
An X-ray CT apparatus comprising:   The image processing unit renders the volume data in a predetermined direction on the basis of the specified position of the puncture needle, and creates a cross-sectional image including the puncture needle. X-ray CT system.   The processing unit takes a difference between tomographic image data constituting the volume data for the volume data, identifies the tomographic image data having a large difference, and determines the puncture needle from the identified tomographic image data. The X-ray CT apparatus according to claim 1 or 2, wherein a position is specified.   The X-ray CT apparatus according to claim 1, further comprising a storage unit that stores a cross-sectional image including the puncture needle. The volume data is a plurality of volume data,
The processing unit identifies the position of the puncture needle in each of the plurality of volume data,
The X-ray CT apparatus according to claim 1, wherein the image processing unit creates a cross-sectional image including the puncture needle for each of the plurality of volume data.   The X-ray CT apparatus according to claim 5, wherein the plurality of volume data are data acquired at different timings.   The X-ray CT apparatus according to claim 1, wherein the cross-sectional image is an oblique image.

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