JP2015084800A - X-ray ct apparatus, and method for controlling x-ray ct apparatus - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a technique allowing for reduction in a radiation dose of an operator when performing paracentesis while performing CT (Computed Tomography) fluoroscopy.SOLUTION: An X-ray CT apparatus according to the embodiment includes an X-ray generation part provided turnably along a circular orbit around a subject, and scans the subject with X-rays by exposing the subject to the X-rays from the X-ray generation part to obtain detection data. The X-ray CT apparatus further includes a calculation part and a scan control part. The calculation part calculates a position on the circular orbit opposite to a paracentesis position of the subject with the subject between the position on the circular orbit and the paracentesis position, as a scan reference position. The scan control part controls the X-ray generation part so as to perform X-ray exposure in some zones including the scan reference position calculated by the calculation part in the circular orbit.

Description

  Embodiments described herein relate generally to an X-ray CT apparatus and a method for controlling the 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. Each of the collected plurality of detection data is A / D converted by the data collection unit and then transmitted to the console device. The console device performs preprocessing and the like on the detected data to create projection data. Then, the console device performs reconstruction processing based on the created projection data, and creates volume data based on tomographic image data or a plurality of tomographic image data. The volume data is a data set representing a three-dimensional distribution of CT values corresponding to a three-dimensional region of the 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 showing a cross section taken along the body axis. There are statues. 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 are simultaneously displayed on a display unit or the like, for example.

  As an imaging method using an X-ray CT apparatus, there is an imaging method called CT fluoroscopy (CTF: Computed Tomography Fluoroscopy). CT fluoroscopy is an imaging method in which an image related to a region of interest of a subject is acquired in real time by continuously irradiating the subject with X-rays. In CT fluoroscopy, images are created in real time by shortening the collection rate of detection data. 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 body fluid accumulated in a body cavity with a tube or the like.

  When an operator performs puncturing while confirming the position of the puncture needle by CT fluoroscopy, not only the subject but also the operator is exposed, and reduction of the exposure amount of both the subject and the operator is an important issue. ing.

JP 2006-320468 A JP 2007-301228 A

  In order to reduce the exposure amount of the subject, for example, the scanning method of the X-ray CT apparatus may be controlled. One scanning method using such an X-ray CT apparatus is a method of performing X-ray exposure only in a predetermined section of a circular orbit centered on the subject. For example, in a method called half scan, X-ray exposure is performed in a section of 180 degrees (+ fan angle) corresponding to half of the entire circular orbit. Half-scan enables a reduction in the amount of X-ray exposure compared to a full scan (method of performing X-ray exposure over the entire circular orbit (360 degrees)), and is effective in reducing the exposure dose of the subject. It is.

  On the other hand, in order to reduce the exposure dose of the operator, for example, by using a puncture tool, the operator can work at a position away from the X-ray exposure position, or the operator can wear protective clothing, etc. And may wear it. However, this technique has a problem that when the surgeon performs work at a position close to the puncture position, the exposure dose is not sufficiently reduced for the hands and arms of the surgeon.

  The present invention has been made to solve the above-described problems, and an object of the present invention is to provide a technique capable of reducing the exposure dose of an operator when performing a puncture while performing CT fluoroscopy. .

The X-ray CT apparatus of the embodiment has an X-ray generation unit that is rotatably provided along a circular orbit around the subject, and exposes the subject to X-rays from the X-ray generation unit. As a result, the subject is scanned with X-rays to obtain detection data. The X-ray CT apparatus includes a calculation unit and a scan control unit. The calculation unit calculates a position on the circular orbit facing the puncture position of the subject with the subject interposed therebetween as the scan reference position. The scan control unit controls the X-ray generation unit to emit X-rays in a part of the circular orbit including the scan reference position calculated by the calculation unit.
In addition, the control method of the X-ray CT apparatus according to the embodiment includes an X-ray generation unit that is provided to be rotatable along a circular orbit around the subject, and the X-ray generation unit performs X to X with respect to the subject. This is a control method of an X-ray CT apparatus that scans a subject with X-rays by exposing a line and acquires detection data. The control method of the X-ray CT apparatus has a calculation step and a scan control step. In the calculation step, a position on the circular orbit facing the puncture position of the subject with the subject interposed therebetween is calculated as the scan reference position. In the scan control step, the X-ray generation unit is controlled so that X-rays are exposed in a part of the circular orbit including the scan reference position calculated in the calculation step.

1 is a block diagram of an X-ray CT apparatus according to a first embodiment. The figure explaining the structure of the puncture needle which concerns on 1st Embodiment. The figure explaining the structure of the puncture device which concerns on 1st Embodiment. Explanatory drawing of the specific | specification part which concerns on 1st Embodiment, a calculation part, and a scanning control part. Explanatory drawing of the specific | specification part which concerns on 1st Embodiment, a calculation part, and a scanning control part. Explanatory drawing of the specific | specification part which concerns on 1st Embodiment, a calculation part, and a scanning control part. The flowchart which shows the outline | summary of operation | movement of the X-ray CT apparatus which concerns on 1st Embodiment. Explanatory drawing of the specific | specification part, the calculation part, and scan control part which concern on the modification of 1st Embodiment. The block diagram of the X-ray CT apparatus which concerns on 2nd Embodiment. The flowchart which shows the outline | summary of operation | movement of the X-ray CT apparatus which concerns on 2nd Embodiment. The block diagram of the X-ray CT apparatus which concerns on 3rd Embodiment. The flowchart which shows the outline | summary of operation | movement of the X-ray CT apparatus which concerns on 3rd Embodiment.

(First embodiment)
FIG. 1 shows the configuration of the X-ray CT apparatus according to the first embodiment. Since “image” and “image data” correspond one-to-one, in the following embodiments, they may be regarded as the same. Further, in the following embodiments, “X-ray dose” and “(X-ray) exposure dose” may be regarded as the same. The X-ray CT apparatus according to this embodiment includes an X-ray generation unit that is rotatably provided along a circular trajectory around a subject being punctured, and the subject is placed at a puncture position where puncture is performed. Control is performed so that X-rays are exposed in a part of a circular orbit including a scan reference position facing each other. In this embodiment, a case where a half scan of a range of 180 degrees (+ fan angle) corresponding to half of the entire circular orbit is performed as a partial section of the circular orbit will be described.

<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 (scan data) of the X-rays that have passed through the subject E. The gantry device 10 includes an X-ray generation unit 11, an X-ray detection unit 12, a rotating body (rotating body) 13, a high voltage generation unit 14, a gantry driving unit 15, an X-ray diaphragm unit 16, and a diaphragm drive. Unit 17 and 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 indicating the intensity distribution of X-rays transmitted through the subject E with an X-ray detection element, generates the detection data as an electrical signal, and generates After the amplified electrical signal is amplified, it is converted into a digital signal and output. As the X-ray detection unit 12, for example, a two-dimensional X-ray detector (planar 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 a predetermined rotation center position. This rotation center position is provided in a placement space in which the subject E is placed. That is, the X-ray generation unit 11 and the X-ray detection unit 12 are provided to be rotatable along a circular orbit around the subject E (a circular orbit around 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 high voltage generator 14 can change the value of the applied high voltage based on the control of the scan controller 44 (described later). Along with the change of the applied high voltage, the X-ray dose (X-ray exposure amount) that the X-ray generation unit 11 exposes to the subject E is also changed.

  The gantry driving unit 15 drives the rotating body 13 to rotate. The X-ray diaphragm unit 16 forms a slit (opening), and changes the size and shape of the slit so that the X-ray fan angle (divergence angle in the channel direction) output from the X-ray generation unit 11 and the X-rays are changed. Adjust the cone angle (spreading angle in the slice direction). The diaphragm drive unit 17 drives the X-ray diaphragm unit 16 to change the size and shape of the slit.

  A data collection unit 18 (DAS: Data Acquisition System) collects detection data from the X-ray detection unit 12 (each X-ray detection element). Then, the data collection unit 18 transmits the collected detection data 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. That is, the placement space for the subject E is provided above the bed top plate 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. Thereby, 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.

  FIG. 1 illustrates an example of an X-ray CT apparatus when an operator such as a doctor performs puncture on the subject E using the puncture needle 35. The X-ray CT apparatus 1 images the inside of the subject E during puncture.

[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 specifying unit 42, a calculating unit 43, a scan control unit 44, a display control unit 45, a storage unit 46, a display unit 47, an operation unit 48, and a control unit 49. And a position acquisition unit 50.

  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 performs reconstruction processing corresponding to the scan range controlled by the scan control unit 44 on the projection data created by the preprocessing unit 41a, and obtains CT image data (tomographic image data and volume data). Create For example, when half scan described later is performed by the scan control unit 44, the reconstruction processing unit 41b performs known half reconstruction processing. The half reconstruction process is a technique for performing the reconstruction process by adding projection data for the fan angle of the X-ray beam to the projection data for 180 degrees around the subject E. As a specific example, in the half reconstruction process, the projection data for 180 degrees around the subject E is added to the projection data for the remaining 180 degrees duplicated using this projection data, and is obtained by a full scan. A reconstruction process similar to the process for the received projection data is performed.

  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 expansion 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. Moreover, when performing CT fluoroscopy, the reconstruction time by the reconstruction process part 41b is shortened. Therefore, the reconstruction processing unit 41b can create real-time CT image data corresponding to the scan.

  The rendering processor 41c performs a rendering process on the volume data created by the reconstruction processor 41b. For example, the rendering processing unit 41c performs MPR display by rendering the volume data created by the reconstruction processing unit 41b in an arbitrary direction (that is, the rendering processing unit 41c creates an MPR image).

  The specifying unit 42 can specify the puncture position where the surgeon performs puncture on the subject E. In this embodiment, the puncture position is described as a position corresponding to the insertion position of the puncture needle 35 on the body surface of the subject E. Such a puncture position may be a position inside or outside the subject E within a predetermined distance from the body surface. The specifying unit 42 specifies the puncture position based on the detection result obtained by the position sensor provided on the puncture needle 35.

  FIG. 2 shows an outline of the configuration of the puncture needle 35. The puncture needle 35 includes a position sensor 35a. The position sensor 35a is provided at the distal end portion of the puncture needle 35, the grip portion of the puncture needle 35 gripped by the operator, or between the distal end portion of the puncture needle 35 and the grip portion. The position sensor 35a generates position information corresponding to coordinate values in a predetermined first coordinate system as a detection result based on, for example, a displacement (displacement direction, displacement amount) from a preset reference position. As such a position sensor 35a, for example, a known magnetic position sensor or optical position sensor can be used.

  As shown in FIG. 3, the position sensor 35 a may be attached to a puncture device (for example, a puncture adapter) 36 that is a means (member) for holding the puncture needle 35. In this case, the position sensor 35 a generates a detection result corresponding to the position of the puncture tool 36.

  For example, the specifying unit 42 can obtain a coordinate position in a predetermined second coordinate system from the detection result obtained by the position sensor 35a, and can specify this coordinate position as the position of the position sensor 35a. The second coordinate system can be the same coordinate system as the first coordinate system. And the specific | specification part 42 makes the attachment position of the position sensor 35a a puncture position, and produces | generates the positional information. That is, the specifying unit 42 specifies the puncture position by regarding the position of the puncture needle 35 or the puncture tool 36 to which the position sensor 35a is attached as the puncture position.

  The specifying unit 42 may specify the insertion position of the puncture needle 35 on the body surface of the subject E as the puncture position based on the detection result obtained by the position sensor 35a. In addition, the specifying unit 42 can repeatedly acquire the detection result obtained by the position sensor 35a, and specify the puncture position based on the detection result each time it is acquired. The position information of the puncture position specified by the specifying unit 42 is sent to the control unit 49.

  Position information of the puncture position specified by the specifying unit 42 is sent from the control unit 49 to the calculating unit 43. The calculation unit 43 calculates a scan reference position for setting a scan range based on the position information of the puncture position. In this embodiment, the calculation unit 43 calculates, as the scan reference position, a position on a circular orbit facing the subject E with respect to the puncture position specified by the specifying unit 42. That is, it can be said that the calculation unit 43 calculates the scan reference position based on the detection result obtained by the position sensor 35a.

  The calculation unit 43 according to this embodiment includes a coordinate conversion unit 43a and a scan reference position calculation unit 43b.

  The coordinate conversion unit 43a converts the puncture position (coordinate value) specified by the specifying unit 42 into a circular orbit coordinate system (third coordinate system). The “circular orbit coordinate system” is a trajectory drawn by the X-ray generator 11 as the rotating body 13 rotates. That is, the coordinate system of the circular orbit means a coordinate system of the rotating body 13 (the gantry device 10).

  The scan reference position calculation unit 43b calculates the scan reference position based on the puncture position whose coordinates have been converted by the coordinate conversion unit 43a and the rotation center position of the circular orbit around which the rotating body 13 rotates. As a specific example, the scan reference position calculation unit 43b calculates, as the scan reference position, a position where a straight line passing through the puncture position specified by the specifying unit 42 and the rotation center position of the circular orbit intersects the circular orbit. More specifically, the scan reference position calculation unit 43b calculates, as the scan reference position, a position where a straight line passing through the rotation center position of the circular orbit starting from the puncture position specified by the specifying unit 42 intersects the circular orbit.

  4 and 5 are explanatory diagrams of processing of the specifying unit 42 and the calculation unit 43 (the coordinate conversion unit 43a and the scan reference position calculation unit 43b). 4 and 5 schematically show cross-sectional views of the subject E and the rotating body 13 (X-ray generation unit 11). Here, it is assumed that the rotating body 13 (the gantry device 10) and the subject E have different coordinate systems (the coordinate system of the rotating body 13: XYZ, the coordinate system of the subject E: xyz). The X direction indicates the lateral direction of the rotating body 13. The Y direction indicates the vertical direction of the rotating body 13. The x direction indicates the lateral direction (coronal direction) of the subject E. The y direction indicates the vertical direction (sagittal direction) of the subject E. In the following description, the position in the Z (z) direction (the body axis direction of the subject E) is not considered, but the puncture position specification and coordinate conversion including the position in the Z (z) direction are performed. It is also possible to do this.

First, the identifying unit 42, the coordinate values of the puncture position P from the coordinate position of the mounting position of the position sensor 35a in the first coordinate system in the second coordinate system (x _{0, y 0)} to identify (see FIG. 4) . Here, as the puncture position P, the position of the position sensor 35a attached to a predetermined position of the puncture needle 35 is specified as a coordinate value.

The coordinate conversion unit 43a converts the coordinate value (x _0, y ₀ ) to the coordinate system of the rotating body 13 and obtains the coordinate value (X _0, Y ₀ ) in the third coordinate system (see FIG. 5). A known method can be used for coordinate conversion (movement, rotation, etc.).

Scanning reference position calculation unit 43b is puncturing position P and the X-ray generation unit 11 from the rotation center position C ₀ Metropolitan circular orbit C which moves, and calculates the scan reference position Sc of the circular orbit C. As a specific example, the scan reference position calculation unit 43b has a straight line L that passes through the coordinate value (X ₀ , Y ₀ ) of the puncture position P and the coordinate value (X _c , Y _c ) of the rotation center position C _0. The position that intersects the trajectory C is calculated as the scan reference position Sc (see FIG. 5).

  The scan control unit 44 controls various operations related to the X-ray scan. For example, the scan control unit 44 controls the high voltage generation unit 14 to apply a high voltage to the X-ray generation unit 11. The scan control unit 44 controls the gantry driving unit 15 to rotationally drive (rotate drive) the rotating body 13. The scan control unit 44 controls the aperture driving unit 17 to operate the X-ray aperture unit 16. The scan control unit 44 controls the bed driving unit 32 to move the bed 31.

  Further, the scan control unit 44 controls the X-ray generation unit 11 via the high voltage generation unit 14 so as to emit X-rays in a part of the circular orbit C including the scan reference position Sc. To do. That is, the “X-ray generator” is a concept including the high voltage generator 14.

  Further, the scan control unit 44 includes a setting unit 44a. The setting unit 44a sets a partial section Cs of the circular orbit C so that the scan reference position Sc is an intermediate position. By setting the scan reference position Sc so as to be an intermediate position of a part of the section Cs, it becomes possible to reliably reduce the exposure dose of the operator's hand and arm portions close to the puncture position. Furthermore, it is easy to ensure the image quality obtained by CT fluoroscopy so that the puncture state (angle, directionality) of the puncture needle and the positional relationship between the puncture needle and the target object can be easily understood. Further, the scan control unit 44 (setting unit 44a) according to this embodiment sets a half-scan range as a partial section Cs of the circular orbit C. Thereby, in addition to the reduction of the exposure amount to the subject E by the known half scan, the exposure amount of the operator's hand and arm portions can be reduced. In particular, by using half reconstruction processing corresponding to half scanning, it is possible to achieve both reduction in exposure dose and ensuring image quality.

  As a specific example, the setting unit 44a scans the scan range so that an intermediate position of a preset half-scan range (180 degrees + fan angle; fan angle is omitted below) becomes the scan reference position Sc. Set.

  FIG. 6 is an explanatory diagram of a half scan range set by the setting unit 44a. FIG. 6 schematically illustrates a cross-sectional view of the subject E and the rotating body 13 (X-ray generation unit 11). When the half scan is performed in a range of 180 degrees, the setting unit 44a sets a range of ± 90 degrees from the scan reference position Sc as a part of the section Cs as shown in FIG. Accordingly, the scan control unit 44 can control the X-ray generation unit 11 (high voltage generation unit 14) so as to emit X-rays in a set partial section Cs.

  The display control unit 45 performs various controls related to image display. For example, control is performed to display the MPR image (axial image, sagittal image, coronal image, oblique image) or the like created by the rendering processing unit 41c on the display unit 47. When the display control unit 45 displays a plurality of MPR images, for example, it becomes easier to grasp the puncture state (angle, directionality) of the puncture needle and the positional relationship between the puncture needle and the target of interest.

  The memory | storage part 46 is comprised by memory | storage devices, such as RAM (Random Access Memory) and ROM (Read Only Memory). The storage unit 46 stores detection data, projection data, or CT image data after reconstruction processing.

  The display unit 47 includes an arbitrary display device such as an LCD (Liquid Crystal Display) or a CRT (Cathode Ray Tube) display. For example, the display unit 47 displays an MPR image obtained by rendering volume data.

  The operation unit 48 is used as an input device that performs various operations on the console device 40. The operation unit 48 includes, for example, a keyboard, a mouse, a trackball, a joystick, and the like. As the operation unit 48, a GUI (Graphical User Interface) displayed on the display unit 47 can be used.

  The position acquisition unit 50 acquires the detection result obtained by the position sensor 35a. The position acquisition unit 50 can acquire a detection result from the position sensor 35a via a wired or wireless transmission path. The detection result of the position sensor 35 a acquired by the position acquisition unit 50 is sent to the control unit 49. The detection result of the position sensor 35 a sent to the control unit 49 is sent to the specifying unit 42.

  The control unit 49 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 49 controls the scan control unit 44 to cause the gantry device 10 to execute, for example, a preliminary scan and a main scan, and collect detection data. In addition, the control unit 49 controls the processing unit 41 to perform various processing (preprocessing, reconstruction processing, MPR processing, etc.) on the detected data. Alternatively, the control unit 49 controls the display control unit 45 to display the CT image on the display unit 47 based on the image data stored in the storage unit 46.

  In this embodiment, the specifying unit 42 is an example of a “specifying unit”, the calculating unit 43 is an example of a “calculating unit”, the scan control unit 44 is an example of a “scan control unit”, and the position sensor 35a is It is an example of “position detection means”.

<Operation>
Next, the operation of the X-ray CT apparatus 1 according to this embodiment will be described.

  FIG. 7 shows an example of an operation flow of the X-ray CT apparatus 1 according to this embodiment. Here, it is assumed that the X-ray CT apparatus 1 can operate in a designated operation mode in the exposure dose reduction mode or the normal mode. In the exposure reduction mode, the X-ray CT apparatus 1 obtains the scan reference position Sc corresponding to the puncture position specified by the position sensor 35a, and then performs CT fluoroscopy by half scanning. In the normal mode, the X-ray CT apparatus 1 performs CT fluoroscopy with a full scan.

(S01)
The X-ray CT apparatus 1 receives an operation mode designation. The control unit 49 monitors whether or not an operation mode is designated via the operation unit 48. When the operation mode is designated through the operation unit 48, the operation of the X-ray CT apparatus 1 proceeds to S02.

(S02)
The control unit 49 determines whether the operation mode designated via the operation unit 48 is the exposure dose reduction mode or the normal mode. When it is determined that the designated operation mode is the normal mode (S02: N), the operation of the X-ray CT apparatus 1 proceeds to S03. On the other hand, when it is determined that the designated operation mode is the exposure reduction mode (S02: Y), the operation of the X-ray CT apparatus 1 proceeds to S04.

(S03)
The X-ray CT apparatus 1 starts CT fluoroscopy with a full scan. When CT fluoroscopy is started, the X-ray CT apparatus 1 performs an X-ray scan on the subject E with a full scan, and creates a plurality of tomographic image data. That is, the X-ray generator 11 emits X-rays to the subject E. The X-ray detection unit 12 detects X-rays that have passed through the subject E. Detection data based on the X-rays 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 preprocessing unit 41a performs preprocessing such as logarithmic conversion processing on the acquired detection data to create projection data. The created projection data is sent to the reconstruction processing unit 41b based on the control of the control unit 49. The reconstruction processing unit 41b creates a plurality of tomographic image data based on the created projection data. In addition, the reconstruction processing unit 41b can create volume data by interpolating a plurality of tomographic image data. With the end of such CT fluoroscopy, the X-ray CT apparatus 1 ends a series of operations (end).

(S04)
The position acquisition unit 50 acquires the detection result obtained by the position sensor 35a. The detection result is sent to the specifying unit 42 via the control unit 49. The specifying unit 42 specifies the puncture position based on the detection result sent from the control unit 49.

(S05)
The calculation unit 43 calculates the position on the circular orbit C that faces the puncture position specified in S04 with the subject E interposed therebetween as the scan reference position. That is, the coordinate conversion unit 43a converts the puncture position (coordinate value) specified in S04 into the coordinate system of the circular orbit C. The scan reference position calculation unit 43b calculates the scan reference position Sc from the puncture position coordinate-converted by the coordinate conversion unit 43a. In this embodiment, the scan reference position calculation unit 43b calculates the scan reference position Sc as described with reference to FIGS. S05 is an example of a “calculation step”.

(S06)
The setting unit 44a sets a part of the section Cs so that the scan reference position Sc calculated in S05 is an intermediate position. In this embodiment, the setting unit 44a sets the half-scan range so that a range of ± 90 degrees from the scan reference position Sc becomes a partial section Cs.

(S07)
The scan control unit 44 controls the X-ray generation unit 11 (high voltage generation unit 14) to emit X-rays in a part of the section Cs set in S04. That is, the scan control unit 44 starts CT fluoroscopy.

  When CT fluoroscopy is started, the X-ray CT apparatus 1 performs X-ray scanning on the subject E by half scanning, and creates a plurality of tomographic image data. That is, the X-ray generator 11 emits X-rays to the subject E. The X-ray detection unit 12 detects X-rays that have passed through the subject E. Detection data based on the X-rays 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 preprocessing unit 41a performs preprocessing such as logarithmic conversion processing on the acquired detection data to create projection data. The created projection data is sent to the reconstruction processing unit 41b based on the control of the control unit 49. The reconstruction processing unit 41b creates a plurality of tomographic image data by a known half reconstruction process based on the created projection data. In addition, the reconstruction processing unit 41b can create volume data by interpolating a plurality of tomographic image data. S07 is an example of a “scan control step”. With the end of such CT fluoroscopy, the X-ray CT apparatus 1 ends a series of operations (end).

  When the volume data is created, the rendering processing unit 41c can perform rendering processing on the created volume data to create an MPR image.

  In this embodiment, when the position sensor 35a is attached to the puncture needle 35 (see FIG. 2), the specifying unit 42 determines the direction of the puncture needle 35 and the position in the depth direction detected by another detection means. And the shape of the puncture needle 35 recognized in advance, the puncture position on the body surface of the subject E may be specified from the attachment position of the position sensor 35a. When the position sensor 35a is attached to the puncture device 36 (see FIG. 3), the specifying unit 42 determines the subject E from the attachment position of the position sensor 35a based on the shape of the puncture device 36 that has been recognized in advance. The puncture position on the body surface may be specified. That is, the specifying unit 42 may specify the puncture position based on the detection result obtained by the position sensor 35a attached to the puncture needle 35 or the puncture tool 36.

  In this case, the position information of the puncture position specified by the specifying unit 42 is sent from the control unit 49 to the calculating unit 43. The calculation unit 43 calculates a scan reference position for setting a scan range based on the position information of the puncture position.

  The processing unit 41, the specifying unit 42, the calculation unit 43, the scan control unit 44, the display control unit 45, and the control unit 49 are, for example, a CPU (Central Processing Unit), a GPU (Graphic Processing Unit), or an ASIC (Application). It may be configured by a processing device (not shown) such as a Specific Integrated Circuit (ROM) and a storage device (not shown) such as a ROM, RAM, or HDD (Hard Disc Drive). The storage device stores a processing program for executing the function of the processing unit 41. The storage device stores a specific unit processing program for executing the function of the specific unit 42. The storage device stores a calculation unit processing program for executing the function of the calculation unit 43. Further, the storage device stores a scan control program for executing the function of the scan control unit 44. The storage device stores a display control program for executing the function of the display control unit 45. The storage device stores a control program for executing the function of the control unit 49. The function of each unit is executed by a processing device such as a CPU executing each program stored in the storage device.

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

  The X-ray CT apparatus 1 according to this embodiment includes an X-ray generation unit 11 that is rotatably provided along a circular orbit C around the subject E, and the X-ray generation unit 11 with respect to the subject E. The subject E is scanned with X-rays by exposing the X-rays to obtain detection data. The X-ray CT apparatus 1 includes a calculation unit 43 and a scan control unit 44. The calculation unit 43 calculates a position on the circular orbit C facing the puncture position P of the subject E with the subject E interposed therebetween as the scan reference position Sc. The scan control unit 44 controls the X-ray generation unit 11 so that X-rays are emitted in a part of the circular orbit C including the scan reference position Sc calculated by the calculation unit 43.

  In this way, the calculation unit 43 calculates the position on the circular orbit C that faces the puncture position P across the subject E as the scan reference position Sc. The scan control unit 44 receives the scan reference position Sc calculated by the calculation unit 43 and controls the X-ray generation unit 11 to emit X-rays in a part of the section Cs including the scan reference position Sc. That is, in the X-ray CT apparatus 1 according to this embodiment, the X-ray generation unit 11 exposes X-rays to the puncture position P via the subject E, so Absorbed by specimen E. Thereby, it becomes possible to reduce the exposure amount of the operator's hand and arm portions close to the puncture position.

(Modification of the first embodiment)
In the first embodiment, the case where the position sensor 35a is attached to the puncture needle 35 or the puncture tool 36 in order to specify the puncture position has been described, but the first embodiment is not limited to this. In this modification, it is assumed that the position sensor 35a is attached to the hand or arm of the operator who performs puncture.

  The configuration of the X-ray CT apparatus according to this modification is the same as the configuration of the X-ray CT apparatus 1 in the first embodiment. The operation of the X-ray CT apparatus according to this modified example uses the detection result obtained by the position sensor 35a attached to the operator's hand or arm, except that the X-ray CT apparatus 1 according to the first embodiment is used. This is the same as the operation and configuration. Hereinafter, an X-ray CT apparatus according to this modification will be described focusing on differences from the first embodiment.

  FIG. 8 is an operation explanatory diagram of the X-ray CT apparatus according to this modification. FIG. 8 is an explanatory diagram of a half-scan range set by the setting unit 44a. 8, parts similar to those in FIG. 6 are given the same reference numerals, and description thereof will be omitted as appropriate.

Based on the detection result obtained by the position sensor 35a attached to the surgeon's arm, the specifying unit 42 according to this modification example uses the second coordinate position from the coordinate position of the position sensor 35a in the first coordinate system. The coordinate value (x _0, y ₀ ) of the position of the position sensor 35a is specified as the puncture position P in the coordinate system. The specifying unit 42 calculates the position P ′ where the subject E is punctured by the puncture needle 35 from the detection result obtained by the position sensor 35a, and calculates the position P ′ as the puncture position P. You may do it.

The coordinate conversion unit 43a according to this modification converts the coordinate value (x _0, y ₀ ) into the coordinate system of the rotating body 13, and the coordinate values (X _0, Y in the third coordinate system as shown in FIG. 8). ₀ ). A known method can be used for coordinate conversion (movement, rotation, etc.).

Scanning reference position calculation unit 43b according to this modification, the puncturing position P and the X-ray generation unit 11 from the rotation center position C ₀ Metropolitan circular orbit C which moves, and calculates the scan reference position Sc of the circular orbit C . As a specific example, the scan reference position calculation unit 43b has a straight line L that passes through the coordinate value (X ₀ , Y ₀ ) of the puncture position P and the coordinate value (X _c , Y _c ) of the rotation center position C _0. The position that intersects the trajectory C is calculated as the scan reference position Sc.

  When the exposure reduction mode is performed by half scanning, the setting unit 44a according to this modification sets a range of ± 90 degrees from the scan reference position Sc as a partial section Cs. Accordingly, the scan control unit 44 can control the X-ray generation unit 11 (high voltage generation unit 14) so as to emit X-rays in a set partial section Cs.

  As described above, the calculation unit 43 according to this modified example can calculate the scan reference position Sc by regarding the position of the body of the surgeon performing the puncture as the puncture position P. Further, the calculation unit 43 according to this modification can calculate the scan reference position Sc based on the detection result obtained by the position sensor 35a attached to the body of the surgeon performing the puncture.

  In addition, although this modification demonstrated the case where the position sensor 35a was attached to the operator's arm who performs puncture, it is not limited to this. The position sensor 35a according to this modification may be attached to another body part such as the hand of an operator who performs puncture.

<Action and effect>
In the X-ray CT apparatus according to this modification, the calculation unit 43 can calculate the scan reference position Sc with the position of the body of the operator performing the puncture as the puncture position P.

  Thus, for example, when the position of the body of the surgeon performing the puncture is specified by the specifying unit 42, the calculation unit 43 calculates the scan reference position Sc using the specified position as the puncture position P. The scan control unit 44 controls the X-ray generation unit 11 so that X-rays are emitted in a part of the circular orbit C including the scan reference position Sc calculated by the calculation unit 43. That is, in the X-ray CT apparatus according to this modification, the X-ray generation unit 11 exposes the X-rays to the puncture position P via the subject E. Absorbed by specimen E. Thereby, it is possible to reduce the exposure dose of the operator's hand and arm portions close to the puncture position while performing CT fluoroscopy.

  Further, the X-ray CT apparatus according to this modification specifies the puncture position P based on the detection result obtained by the position detection means (for example, the position sensor 35a) attached to the body of the operator who performs the puncture. The specifying unit 42 can be included. The calculating unit 43 calculates the scan reference position Sc for the puncture position P specified by the specifying unit 42.

  In this manner, the specifying unit 42 specifies the puncture position P from the position of the body of the operator who performs puncture. The calculation unit 43 calculates a position on the circular orbit C facing the puncture position P specified by the specifying unit 42 across the subject E as the scan reference position Sc. In the X-ray CT apparatus according to this modification, the X-ray generator 11 exposes X-rays to the puncture position P via the subject E, and thus the exposed X-rays are the subject E. Is absorbed by. Thereby, it is possible to reduce the exposure dose of the operator's hand and arm portions close to the puncture position while performing CT fluoroscopy.

(Second Embodiment)
In the first embodiment or the modification thereof, the case where the puncture position is specified using the detection result obtained by the position sensor 35a attached to the puncture needle 35 or the like has been described, but the puncture position is not used without using the position sensor 35a. Can be specified. In the second embodiment, the puncture position P is specified based on volume data including the puncture position of the subject E being punctured acquired in advance by a preliminary scan or the like.

  FIG. 9 shows a configuration of an X-ray CT apparatus according to the second embodiment. 9, parts that are the same as those in FIG. 1 are given the same reference numerals, and descriptions thereof will be omitted as appropriate. In the X-ray CT apparatus according to this embodiment, the specifying unit specifies the puncture position based on the volume data, and the calculation unit is on the circular orbit C facing the subject E with respect to the specified puncture position. The position is calculated as the scan reference position Sc. Hereinafter, the X-ray CT apparatus according to the second embodiment will be described focusing on differences from the first embodiment.

<Device configuration>
As shown in FIG. 9, the X-ray CT apparatus 1a according to the second embodiment includes a gantry device 10, a couch device 30, and a console device 40a.

  The main differences between the configuration of the console device 40a and the configuration of the console device 40 according to the first embodiment are that the position acquisition unit 50 is omitted, and that a specifying unit 42a is provided instead of the specifying unit 42. The control unit 49a is provided in place of the control unit 49.

  The control unit 49 according to the first embodiment performs specific control of the puncture position using the detection result obtained by the position sensor 35a. On the other hand, the control unit 49a performs specific control of the puncture position based on the volume data. For other controls, the control unit 49 a performs the same control as the control unit 49.

  In the second embodiment, volume data including the puncture position of the subject E is created in advance by performing a preliminary scan on the subject E prior to specifying the puncture position. The specifying unit 42a can specify the puncture position based on the volume data. As a specific example, the specifying unit 42a specifies a voxel indicating the puncture needle 35 and a voxel indicating the body surface of the subject E from the voxel group in the obtained volume data. At this time, the specifying unit 42a can specify a voxel indicating the puncture needle 35 and a voxel indicating the body surface of the subject E based on the CT value. Then, the specifying unit 42a specifies a voxel indicating the puncture position on the body surface of the subject E from the voxel indicating the specified puncture needle 35 and the voxel indicating the body surface of the subject E. For example, the specifying unit 42a specifies the voxel indicating the puncture needle 35 on the body surface of the subject E by sequentially tracking the voxels indicating the puncture needle 35, and employs the specified voxel as the voxel indicating the puncture position. can do.

<Operation>
Next, the operation of the X-ray CT apparatus 1a according to this embodiment will be described.

  FIG. 10 shows an example of an operation flow of the X-ray CT apparatus 1a according to this embodiment. Here, it is assumed that the X-ray CT apparatus 1a is operable in a designated operation mode in the exposure dose reduction mode or the normal mode. In the exposure reduction mode, the X-ray CT apparatus 1a performs a preliminary scan, obtains a scan reference position Sc corresponding to the puncture position specified based on the volume data obtained by the preliminary scan, and then performs a CT by half scan. Perform fluoroscopy. In the normal mode, the X-ray CT apparatus 1a performs CT fluoroscopy with a full scan.

(S11)
First, the X-ray CT apparatus 1a accepts designation of an operation mode. The control unit 49a monitors whether or not the operation mode is designated via the operation unit 48. When the operation mode is designated via the operation unit 48, the operation of the X-ray CT apparatus 1a proceeds to S12.

(S12)
The control unit 49a determines whether the operation mode designated through the operation unit 48 is the exposure dose reduction mode or the normal mode. When it is determined that the designated operation mode is the normal mode (S12: N), the operation of the X-ray CT apparatus 1a proceeds to S13. On the other hand, when it is determined that the designated operation mode is the exposure reduction mode (S12: Y), the operation of the X-ray CT apparatus 1a proceeds to S14.

(S13)
As in S03, the X-ray CT apparatus 1a performs CT fluoroscopy with a full scan and creates volume data. With the completion of such CT fluoroscopy, the X-ray CT apparatus 1a ends a series of operations (end).

(S14)
The X-ray CT apparatus 1a performs a preliminary scan. In the preliminary scan, X-ray exposure is performed on the entire circular orbit (360 degrees). Specifically, under the control of the scan control unit 44, the X-ray generation unit 11 irradiates the subject E with X-rays over the entire circular orbit.

(S15)
The X-ray detection unit 12 of the X-ray CT apparatus 1a detects X-rays that have passed through the subject E and acquires the detection data. 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 41 (pre-processing unit 41a).

(S16)
The X-ray CT apparatus 1a creates projection data based on the detection data obtained in S15. Specifically, the preprocessing unit 41a creates projection data by performing preprocessing such as logarithmic conversion processing, offset correction, sensitivity correction, and beam hardening correction on the detection data obtained in S15. . The created projection data is sent to the reconstruction processing unit 41b based on the control of the control unit 49a.

(S17)
The X-ray CT apparatus 1a creates volume data based on the projection data created in S16. Specifically, the reconstruction processing unit 41b creates a plurality of tomographic image data based on the projection data created in S16. Then, the reconstruction processing unit 41b creates volume data by interpolating a plurality of tomographic image data.

(S18)
The identification unit 42a identifies the puncture position as described above based on the volume data created in S17.

(S19)
The calculation unit 43 calculates a position on the circular orbit C facing the subject E with respect to the puncture position specified in S18 as a scan reference position. That is, the coordinate conversion unit 43a converts the puncture position (coordinate value) identified in S18 into the circular orbit C coordinate system. The scan reference position calculation unit 43b calculates the scan reference position Sc from the puncture position coordinate-converted by the coordinate conversion unit 43a. In this embodiment, the scan reference position calculation unit 43b calculates the scan reference position Sc as in the first embodiment or its modification. S19 is an example of a “calculation step”.

(S20)
The setting unit 44a sets a part of the section Cs so that the scan reference position Sc calculated in S19 is an intermediate position. In this embodiment, the setting unit 44a sets the half-scan range so that a range of ± 90 degrees from the scan reference position Sc becomes a partial section Cs.

(S21)
The scan control unit 44 controls the X-ray generation unit 11 (high voltage generation unit 14) so as to emit X-rays in a part of the section Cs set in S20. That is, the scan control unit 44 performs CT fluoroscopy and creates volume data as in S07. S21 is an example of a “scan control step”. With the completion of such CT fluoroscopy, the X-ray CT apparatus 1a ends a series of operations (end).

  The specifying unit 42a and the control unit 49a may also be configured by a processing device (not shown) such as a CPU, GPU, or ASIC and a storage device (not shown) such as a ROM, RAM, or HDD, for example. The storage device stores a specific unit processing program for executing the function of the specific unit 42a. The storage device stores a control program for executing the function of the control unit 49a. A processing device such as a CPU executes the functions of each unit by executing each program stored in the storage device.

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

  The X-ray CT apparatus 1a of this embodiment can include a specifying unit 42a. The specifying unit 42a specifies the puncture position based on the volume data obtained by reconstructing the projection data created from the detection data. The calculating unit 43 calculates the scan reference position Sc for the puncture position specified by the specifying unit 42a. The scan control unit 44 controls the X-ray generation unit 11 so that X-rays are emitted in a part of the circular orbit C including the scan reference position Sc calculated by the calculation unit 43. Thereby, it is possible to reduce the exposure dose of the operator's hand and arm portions close to the puncture position while performing CT fluoroscopy. In addition, hardware such as a position sensor and a position acquisition unit for specifying the puncture position can be eliminated. Furthermore, the puncture position can be accurately specified by the volume data.

(Third embodiment)
In the first embodiment or the modified example and the second embodiment, the case where the puncture position is specified using the detection result obtained by the position sensor 35a or the puncture position is specified based on the volume data has been described. However, the present invention is not limited to this. In the third embodiment, the puncture position is designated via the operation unit 48 as designation means.

  FIG. 11 shows the configuration of an X-ray CT apparatus according to the third embodiment. In FIG. 11, the same parts as those in FIG. In the X-ray CT apparatus according to this embodiment, using the puncture position designated via the operation unit 48, the calculation unit uses the position on the circular orbit C facing the subject E as the scan reference position Sc. calculate. Hereinafter, the X-ray CT apparatus according to the third embodiment will be described focusing on differences from the first embodiment.

<Device configuration>
As shown in FIG. 11, the X-ray CT apparatus 1b according to the third embodiment includes a gantry device 10, a couch device 30, and a console device 40b.

  The main difference between the configuration of the console device 40b and the configuration of the console device 40 according to the first embodiment is that the specifying unit 42 and the position acquisition unit 50 are omitted, and a control unit 49b is provided instead of the control unit 49. This is the point.

  The control unit 49 according to the first embodiment performs specific control of the puncture position using the detection result obtained by the position sensor 35a. On the other hand, the control unit 49 b performs calculation control of the scan reference position Sc for the puncture position designated via the operation unit 48. For other controls, the control unit 49b performs the same control as the control unit 49.

<Operation>
Next, the operation of the X-ray CT apparatus 1b according to this embodiment will be described.

  FIG. 12 shows an example of an operation flow of the X-ray CT apparatus 1b according to this embodiment. Here, it is assumed that the X-ray CT apparatus 1b can operate in a designated operation mode in the exposure dose reduction mode or the normal mode. In the exposure reduction mode, the X-ray CT apparatus 1b obtains the scan reference position Sc corresponding to the puncture position designated via the operation unit 48, and then performs CT fluoroscopy by half scanning. In the normal mode, the X-ray CT apparatus 1b performs CT fluoroscopy with a full scan.

(S31)
The X-ray CT apparatus 1b accepts an operation mode designation. The control unit 49b monitors whether or not the operation mode is designated via the operation unit 48. When the operation mode is designated via the operation unit 48, the operation of the X-ray CT apparatus 1b proceeds to S32.

(S32)
The control unit 49b determines whether the operation mode designated through the operation unit 48 is the exposure dose reduction mode or the normal mode. When it is determined that the designated operation mode is the normal mode (S32: N), the operation of the X-ray CT apparatus 1b proceeds to S33. On the other hand, when it is determined that the designated operation mode is the exposure reduction mode (S32: Y), the operation of the X-ray CT apparatus 1b proceeds to S34.

(S33)
As in S03, the X-ray CT apparatus 1b starts CT fluoroscopy with a full scan. With the end of CT fluoroscopy, the X-ray CT apparatus 1b ends a series of operations (end).

(S34)
The X-ray CT apparatus 1b accepts designation of the puncture position. The control unit 49b monitors whether or not a puncture position is designated via the operation unit 48. When the puncture position is designated via the operation unit 48, the operation of the X-ray CT apparatus 1b proceeds to S35.

(S35)
The calculation unit 43 calculates a position on the circular orbit C facing the subject E with respect to the puncture position designated in S34 as a scan reference position. That is, the coordinate conversion unit 43a converts the puncture position (coordinate value) designated in S34 into the coordinate system of the circular orbit C. The scan reference position calculation unit 43b calculates the scan reference position Sc from the puncture position coordinate-converted by the coordinate conversion unit 43a. In this embodiment, the scan reference position calculation unit 43b calculates the scan reference position Sc as in the first embodiment or its modification. Note that the puncture position specified via the operation unit 48 may be a coordinate value in the coordinate system of the circular orbit C. In this case, it is not necessary to perform coordinate conversion by the coordinate conversion unit 43a. S35 is an example of a “calculation step”.

(S36)
The setting unit 44a sets a part of the section Cs so that the scan reference position Sc calculated in S35 is an intermediate position. In this embodiment, the setting unit 44a sets the half-scan range so that a range of ± 90 degrees from the scan reference position Sc becomes a partial section Cs.

(S37)
The scan control unit 44 controls the X-ray generation unit 11 (high voltage generation unit 14) to emit X-rays in a part of the section Cs set in S36. That is, the scan control unit 44 starts CT fluoroscopy.

  When CT fluoroscopy is started, the X-ray CT apparatus 1b performs X-ray scanning with respect to the subject E by half scanning, as in S07, and creates a plurality of tomographic image data. S37 is an example of a “scan control step”. With the end of CT fluoroscopy, the X-ray CT apparatus 1b ends a series of operations (end).

  The control unit 49b may also be configured by a processing device (not shown) such as a CPU, GPU, or ASIC and a storage device (not shown) such as a ROM, RAM, or HDD, for example. The storage device stores a control program for executing the function of the control unit 49b. A processing device such as a CPU executes the functions of each unit by executing each program stored in the storage device.

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

  In the X-ray CT apparatus 1b of this embodiment, the calculation unit 43 can calculate the scan reference position Sc for the puncture position specified by the specifying means (for example, the operation unit 48). The scan control unit 44 controls the X-ray generation unit 11 so that X-rays are emitted in a part of the circular orbit C including the scan reference position Sc calculated by the calculation unit 43. Thereby, it is possible to reduce the exposure dose of the operator's hand and arm portions close to the puncture position while performing CT fluoroscopy. In addition, hardware such as a position sensor and a position acquisition unit for specifying the puncture position can be eliminated.

(Other)
In the above embodiment, the method of using a position sensor or volume data has been described as the method for specifying the puncture position by the specifying unit. However, the method is not limited to this. For example, the specifying unit may specify the puncture position by performing image processing on an image taken by a camera as a photographing unit. For example, the specifying unit reversely calculates a camera position from an image obtained by photographing a range including a puncture position and a plurality of predetermined reference positions with a camera, and then calculates a three-dimensional coordinate position of the puncture position. The position may be estimated and specified as the puncture position. In addition, as a puncture position, a puncture needle, a puncture device, or an operator's hand or arm may be photographed with a camera to specify these positions. Alternatively, the specifying unit may specify the puncture position from the image taken by the camera using a preset area on the body surface of the subject E, the shape of the puncture needle, and the like. Further, the specifying unit may specify the puncture position using a reference distance in an image captured by a camera set to a predetermined position and orientation.

  In the above embodiment, as an example, a half scan in which X-ray exposure is performed in a section of 180 degrees (+ fan angle) corresponding to half of the entire circular orbit as a part of the circular orbit, The range of scanning is not limited to this. The range of scanning may be a range that can obtain the required image quality.

  In the above embodiment, an X-ray CT apparatus that reduces the exposure amount by changing the scan range in real time during puncture by changing the scan range when a change in the puncture position is detected. It is possible to provide.

  In the above-described embodiment, the X-ray CT apparatus has been described as having the rotating body 13 provided with the X-ray generation unit 11 and the X-ray detection unit 12 and configured to be rotatable, but is not limited thereto. . The X-ray CT apparatus may be of a type in which a large number of detection elements are arrayed in a ring shape and the X-ray tube rotates around the subject.

  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, 1a, 1b X-ray CT apparatus 10 Base apparatus 11 X-ray generation part 12 X-ray detection part 13 Rotor 14 High voltage generation part 15 Base drive part 16 X-ray aperture part 17 Aperture drive part 18 Data collection part 30 Sleeper apparatus 32 Bed driving unit 33 Bed top plate 34 Base 35 Puncture needle 35a Position sensor 36 Puncture tool 40, 40a, 40b Console device 41 Processing unit 41a Preprocessing unit 41b Reconfiguration processing unit 41c Rendering processing unit 42, 42a Identification unit 43 Calculation Unit 43a coordinate conversion unit 43b scan reference position calculation unit 44 scan control unit 44a setting unit 45 display control unit 46 storage unit 47 display unit 48 operation unit 49, 49a, 49b control unit 50 position acquisition unit C circular trajectory Cs partial section E Subject P Puncture position Sc Scan reference position

Claims (9)

An X-ray generation unit is provided so as to be rotatable along a circular orbit around the subject, and the subject is exposed to X-rays by exposing the subject to X-rays from the X-ray generation unit. An X-ray CT apparatus that scans with a line and acquires detection data,
A calculation unit that calculates a position on the circular orbit facing the puncture position of the subject across the subject as a scan reference position;
A scan control unit that controls the X-ray generation unit so as to expose the X-ray in a part of the circular orbit including the scan reference position calculated by the calculation unit. X-ray CT apparatus. The calculation unit includes:
The X-ray CT apparatus according to claim 1, wherein a position where a straight line passing through the puncture position and a rotation center position of the circular orbit intersects the circular orbit is calculated as the scan reference position. The scan control unit
The X-ray generation unit is controlled so as to expose the X-rays in the partial section in which the scan reference position calculated by the calculation unit is an intermediate position. 2. The X-ray CT apparatus according to 2. The scan control unit
The X-ray CT apparatus according to claim 1, wherein a half scan is performed in a section including the scan reference position calculated by the calculation unit. The calculation unit includes:
The X-ray CT apparatus according to any one of claims 1 to 4, wherein the scan reference position is calculated with respect to the puncture position designated by a designation means. The calculation unit includes:
The X-ray according to any one of claims 1 to 4, wherein the scan reference position is calculated using a puncture needle, a puncture tool, or a position of an operator performing puncture as the puncture position. CT device. Based on the detection result obtained by the position detection means attached to the body of the puncture needle, the puncture tool, or the operator performing the puncture, including a specifying unit for specifying the puncture position,
The calculation unit includes:
The X-ray CT apparatus according to claim 1, wherein the scan reference position is calculated with respect to the puncture position specified by the specifying unit. Including a specifying unit that specifies the puncture position based on volume data obtained by reconstructing projection data created from the detection data;
The calculation unit includes:
The X-ray CT apparatus according to claim 1, wherein the scan reference position is calculated with respect to the puncture position specified by the specifying unit. An X-ray generation unit is provided so as to be rotatable along a circular orbit around the subject, and the subject is exposed to X-rays by exposing the subject to X-rays from the X-ray generation unit. A method for controlling an X-ray CT apparatus that scans with a line and acquires detection data,
A calculation step of calculating a position on the circular orbit facing the puncture position of the subject across the subject as a scan reference position;
A scan control step of controlling the X-ray generation unit so as to expose the X-rays in a part of the circular orbit including the scan reference position calculated in the calculation step. A control method for the X-ray CT apparatus.

Images