JP7453313B2 - X-ray photography equipment and X-ray photography method - Google Patents

Description

The present disclosure relates to an X-ray imaging device and an X-ray imaging method.

As X-ray imaging devices, the devices described in Patent Documents 1, 2, and 3 are known. Patent Document 1 describes an apparatus that calculates the degree of roughness of mandibular cortical bone from a dental panoramic image or the like to support diagnosis of osteoporosis. In this device, the contour of the mandible is extracted from a panoramic image or the like, and a region of interest is set using the contour of the mandible. Line segments including the cortical bone line segment and the roughened part line segment are extracted from the image of the region of interest, feature amounts are calculated, and the degree of roughness of the mandibular cortical bone is calculated. Patent Document 2 discloses a method of generating biomarkers by analyzing medical image data such as CT images. Biomarkers are applied to the evaluation of cancer images. Biomarkers may be obtained from CT images of the liver, lungs, esophagus, etc., or may be obtained from dental CT images or dental X-ray images. Biomarkers, when obtained from dental images, are indicators of the extent, spread, grading or staging of dental cancer. Patent Document 3 describes a technique that allows accurate positioning of a target location in a relatively short time in a CT imaging apparatus using an X-ray cone beam.

Japanese Patent Application Publication No. 2017-164412 Special Publication No. 2010-531155 Japanese Patent Application Publication No. 2008-178714

In dental diagnosis, when obtaining a CT image of a specific part (for example, a part of interest that may be a treatment target), it is necessary to specify the position of the part and determine the imaging area. For this positioning, a scout image obtained by X-ray imaging an area that is wider than the imaging area and includes the imaging area is used. For example, in the apparatus described in Patent Document 3, a subject is photographed under two positional conditions in which the positional relationships between the X-ray generator, the subject, and the image sensor are different. Then, a target location (corresponding to the above-mentioned specific portion) is determined on the scout images obtained in these two directions, two-dimensional position data of the target location is calculated, and further, a three-dimensional position is calculated. CT imaging is performed with this three-dimensional position as the center of rotation, and a CT image is obtained. In addition to such two-directional scout images, panoramic scout images may also be used.

When using a scout image for positioning for CT imaging, an operator such as a dentist looks at the image and specifies a position that he or she thinks will be a specific part to be CT imaged. This work is troublesome for the operator. Even if a certain subject may have been CT imaged in the past, the operator needs to perform this positioning operation again. In this case, if the posture of the subject changes between the past image and the current image, the surgeon may specify an incorrect position (for example, a position that is slightly different from a specific part). As described above, conventionally, in positioning for X-ray imaging such as CT imaging, there have been problems of troublesomeness and accuracy.

The present disclosure describes an X-ray imaging apparatus and an X-ray imaging method that can simply and accurately position X-ray imaging.

One aspect of the present invention is an X-ray imaging apparatus that takes an X-ray image of the head of a subject, which includes an X-ray generator that irradiates the head with X-rays, and an X-ray that detects the X-rays that have passed through the head. a support part that supports the X-ray generator and the X-ray detector such that the central space in which the head is placed is located between the X-ray generator and the X-ray detector; A subject holder that holds the subject so as to be positioned in the space, and a support part that allows the X-ray generator and the X-ray detector to rotate around the central space and take X-ray images of a predetermined area within the central space. A drive mechanism configured to move an X-ray generator and an X-ray detector by driving, and a first region corresponding to a first portion that is a part of the inside of the head are X-rayed. A storage unit capable of storing the obtained first region X-ray image data; An image is created for the second X-ray image data based on the second area X-ray image data obtained by radiography and the first X-ray image data based on the first area X-ray image data acquired from the storage unit. A determination unit that determines a third region corresponding to the first portion within the second region by performing recognition processing, and a determination unit that controls a drive mechanism to perform X-ray imaging of the third region. A control unit that moves the ray generator and the X-ray detector.

In this X-ray imaging apparatus, the head of a subject is placed in a central space, and an X-ray generator irradiates the head with X-rays. An X-ray detector detects X-rays that have passed through the head, thereby obtaining X-ray image data. The storage unit can store first region X-ray image data obtained by X-ray photographing a first region corresponding to a first portion that is a part of the inside of the head. When the first area X-ray image data is stored in the storage unit, the determination unit performs X-ray imaging of the first area X-ray image data and the second area based on the first area X-ray image data. Image recognition processing is performed on the second X-ray image data based on the obtained second region X-ray image data, and a third region corresponding to the first portion is determined. Then, the control unit controls the drive mechanism to cause the X-ray generator and the X-ray detector to take X-ray images of the third region. Therefore, while the subject is held in the subject holder, a second region inside the head of the subject is photographed to obtain second region X-ray image data, and then data corresponding to the first region within the head is obtained. The third region can be automatically (or semi-automatically) radiographed. Therefore, positioning work by the operator or the like with respect to the second region X-ray image data or the second X-ray image data is no longer necessary. Even if the posture of the subject changes between the first X-ray image data derived from the past image and the second X-ray image data derived from the current image, the third region is determined based on image recognition. This improves position accuracy. According to the X-ray imaging apparatus of the present disclosure, positioning for X-ray imaging can be performed simply and accurately.

The first X-ray image data is three-dimensional image data obtained by CT imaging the first portion or tomosynthesis image data obtained by tomosynthesis imaging the first portion, and the second X-ray image The data may be one or more projection image data obtained by X-ray imaging the second portion. In this case, the third region is determined from the projection image data using three-dimensional image data having three-dimensional volume data or tomosynthesis image data. Therefore, it is possible to more accurately position the third region for X-ray imaging.

The second X-ray image data may be two projection image data obtained by X-ray photographing the second portion from two different directions. In this case, since the three-dimensional position in space is determined using two projection image data obtained by taking X-rays from two directions, it is possible to more accurately position the third area for taking X-rays. can do.

The determination unit may perform image recognition processing on the first X-ray image data by referring to the X-ray irradiation angles when the two projection image data were obtained. In this case, the determination unit can generate determination image data based on the first X-ray image data such that it is easy to detect a matching point with the specific portion of the second X-ray image data. The third region determination process (ie automatic positioning) can be performed quickly.

The determination unit sets the image data obtained by two-dimensionally processing the three-dimensional image data as the first X-ray image data, and compares the first X-ray image data and the second X-ray image data to determine the third X-ray image data. The area may also be determined.

The determination unit may determine the third region by comparing the Raysum image data of the first X-ray image data and the second X-ray image data. The Raysum image data may include information in a predetermined direction (thickness direction) in the first X-ray image data. Therefore, by using the Raysum image data for comparison, the accuracy of image recognition can be improved. The determination unit can more accurately detect points that match the specific portion of the second X-ray image data.

The determination unit may calculate a change in the position or orientation of the first portion of the head based on the first region and the third region. In this case, changes (deviation, etc.) with respect to past shooting times are calculated. Therefore, the change can be presented, and the X-ray image of the third region (third X-ray image) can be corrected based on the change.

The determination unit inputs the first X-ray image data and the second X-ray image data to a determination model generated by machine learning, and determines a first portion in the second region output from the determination model. A region estimated to correspond to the region is determined to be the third region, and the determination model corresponds to the first information including the first X-ray image data and the first portion within the second X-ray image data. The model may be a trained model that has been machine-learned using teacher data that includes second information that includes a third region. By using a determination model that has learned the correspondence (for example, identity) between the first X-ray image data and the second X-ray image data, the determination accuracy can be improved. For example, even if the second X-ray image data is projection image data and includes information on both the right tooth and the left tooth, the first X-ray image data is a local image of either the left or right tooth. By using the determination model learned using the data, it is possible to easily and accurately position the third region for X-ray imaging.

The X-ray imaging device further includes a display unit, the determination unit calculates a change in orientation of the first portion of the head based on the first X-ray image data and the second X-ray image data, When processing the X-ray image data obtained by X-ray photography of the third region and displaying it on the display unit as an X-ray image, the X-ray image may be generated based on the calculated change in orientation.

The determination unit calculates a change in the orientation of the first portion of the head based on the first X-ray image data and the second X-ray image data, and calculates the change in the orientation of the first portion of the head, and The trajectory of movement of the generator and the X-ray detector may be set.

Another aspect of the present invention is an X-ray imaging apparatus that takes an X-ray image of the head of a subject, and includes an X-ray generator that irradiates the head with X-rays, and an X-ray that detects the X-rays that have passed through the head. An X-ray device comprising: a detector; and a support portion that supports an X-ray generator and an X-ray detector such that a central space in which the head is placed is located between the X-ray generator and the X-ray detector. An X-ray photographing method using an imaging device, the method comprising: X-ray photographing a first region corresponding to a first portion consisting of a part of the inside of the head to obtain first region X-ray image data; an acquisition step, holding the subject such that the head is located in the central space, and capturing a second region corresponding to at least a second region comprising at least a portion within the head and comprising at least a portion of the first region; a second acquisition step of X-ray photographing the region to obtain second region X-ray image data; and second X-ray image data based on the second region X-ray image data and the first region acquired in the first acquisition step. a processing step of determining a third region corresponding to the first portion within the second region by performing image recognition processing on the first X-ray image data based on the X-ray image data; a control step of driving the support part to move the X-ray generator and the X-ray detector so as to X-ray photograph the area. According to this X-ray imaging method, the same effects as those of the above-mentioned X-ray imaging apparatus can be achieved.

According to some aspects of the present disclosure, it is possible to easily and accurately position the third region for X-ray imaging.

FIG. 1 is a diagram showing the configuration of an X-ray imaging apparatus according to an embodiment. FIG. 2 is a diagram showing the main body of the X-ray imaging apparatus in FIG. 1, viewed diagonally from above. 2 is a diagram showing a schematic configuration of an imaging section of the main body of the X-ray imaging apparatus in FIG. 1. FIG. FIG. 4 is a plan view showing a schematic configuration of the upper frame in FIG. 3. FIG. 4 is a side view showing a schematic configuration of the upper frame in FIG. 3. FIG. FIG. 2 is a diagram illustrating an example of the functional configuration of the X-ray imaging apparatus main body in FIG. 1. FIG. 1 is a diagram illustrating an example of a functional configuration of an X-ray imaging system including a computer of an X-ray imaging apparatus. FIG. 2 is a diagram illustrating an example of a processing flow executed by an X-ray imaging apparatus. 8 is a diagram illustrating an example of a process flow of the target area determination process in FIG. 7. FIG. FIG. 2 is a diagram schematically showing an outline of a determination model. FIG. 3 is a diagram showing an example of a data structure of a first X-ray image. FIG. 7 is a diagram showing a procedure for creating a scout image as a second X-ray image. It is a figure which shows an example of the scout image image|photographed from two different directions. FIG. 3 is a diagram showing an example of image recognition for a first X-ray image. It is a figure which shows an example of the 3rd area|region displayed on the 2nd X-ray image. FIG. 16 is a diagram illustrating an example in which the X-ray image portion of FIG. 15 is omitted and the arrangement and/or size of the outline is changed. FIG. 2 is a conceptual diagram for explaining tomosynthesis imaging viewed from the Z-axis direction. FIG. 3 is a diagram for explaining a first setting example of rotation axes of an X-ray generator and an X-ray detector. FIG. 7 is a diagram for explaining a second setting example of the rotation axes of the X-ray generator and the X-ray detector. FIG. 7 is a diagram for explaining a third setting example of the rotation axes of the X-ray generator and the X-ray detector.

Embodiments of the present invention will be described below with reference to the drawings. In addition, in the description of the drawings, the same elements are given the same reference numerals, and overlapping description will be omitted. In this specification, an XYZ orthogonal coordinate system and an xyz orthogonal coordinate system are used. The XYZ orthogonal coordinate system and the xyz orthogonal coordinate system will be described later.

In addition, in this specification, the terms "imaging area," "first area," "second area," and "third area" refer to absolute coordinates defined on a fixed part such as the support 4. This is an area based on an XYZ orthogonal coordinate system as a system. On the other hand, the terms "first part," "second part," and "third part" are parts within the head B of the subject A. For example, when the same subject A undergoes X-ray imaging multiple times using the X-ray imaging device 1, the "third portion" corresponding to the "third region" that is the current imaging target region is In head B, the "third part" is the same or approximately the same as the "first part" at the time of past photography, but if the orientation or posture of head B has changed, the "third part" has been photographed. The "third region" that is the region and the "first region" that is the region where the "first portion" is photographed are different in the XYZ orthogonal coordinate system as the absolute coordinate system. The position of the "nth region" (n is a natural number) is a fixed support element (in this embodiment, a fixed support element such as the column 4) that supports the imaging system consisting of an X-ray generator and an X-ray detector. means one position of a region in space (specifically, the position of a region in a coordinate system of spatial coordinates) where an element) exists. Similarly, the position of the "mth part" (m is a natural number) means the position of one partial region in or on the body of the subject.

The X-ray imaging apparatus 1 of this embodiment will be described with reference to FIGS. 1 to 3. As shown in FIGS. 1 and 2, the X-ray imaging apparatus 1 is an apparatus for X-ray imaging the head B of a subject A. The X-ray imaging apparatus 1 is used, for example, for dental diagnosis or dental treatment of a subject A, who is a patient. The X-ray imaging apparatus 1 is used, for example, when implant treatment is to be performed on a patient, and performs CT imaging of a target region R (see FIG. 3) in the head B of a subject A.

The X-ray imaging device 1 includes, for example, an X-ray imaging device main body 2 that is installed in an X-ray-proof room and performs X-ray imaging, and an image recognition process etc. based on the X-ray detection signal output from the X-ray imaging device main body 2. and an information processing device 70 (see FIG. 7) that performs predetermined information processing including. The X-ray imaging apparatus body 2 includes a first imaging section 10 for performing CT imaging, etc., a second imaging section 100 for performing cephalometric imaging, etc., and the first imaging section 10 and the second imaging section 10 for performing CT imaging, etc. The apparatus includes a control device 50 (see FIG. 6) that controls X-ray imaging in the section 100, and an operation panel 90 that allows an operator or the like to operate the X-ray imaging apparatus main body 2.

The operation panel 90 may be incorporated into the X-ray imaging apparatus main body 2 as shown in FIG. 1, or may be provided separately from the X-ray imaging apparatus main body 2. The operation panel 90 may be installed at a location away from the X-ray imaging apparatus main body 2. The X-ray imaging apparatus 1 includes an X-ray irradiation operation section 92 for instructing the X-ray imaging apparatus main body 2 to perform X-ray imaging. The X-ray irradiation operation unit 92 includes an emission switch 93 for causing the X-ray imaging apparatus main body 2 to perform X-ray irradiation. Emission switch 93 has one or more buttons. The emission switch 93 is a dead man's switch or the like that allows X-ray irradiation when the button is pressed, and stops the X-ray irradiation when the button is released. The X-ray irradiation operation section 92 is provided, for example, on a wall surface outside the X-ray-proof room. The information processing device 70 includes, for example, a computer or a workstation connected to the X-ray imaging device main body 2. The X-ray imaging apparatus main body 2 may be equipped with the information processing device 70 as a part of the X-ray imaging apparatus main body 2.

In the present embodiment, X-ray imaging is performed in the X-ray imaging apparatus main body 2, and the X-ray detection signal obtained by the X-ray imaging is image-processed by the information processing device 70, resulting in an X-ray image (a scout image to be described later). is obtained. The information processing device 70 performs positioning for CT imaging based on this X-ray image. This positioning means determining the center position of the CT imaging target area (ie, FOV; Field of View). The information processing device 70 outputs information indicating the center position of CT imaging to the control device 50 of the X-ray imaging device main body 2, and the control device 50 controls the first imaging section 10 based on this information, CT imaging is performed in a predetermined target area within the head B of the subject A.

The X-ray imaging apparatus main body 2 includes a base 3 fixed (installed) on the floor, a column 4 fixed on the base 3 and extending in the vertical direction, and a column 4 extending horizontally from one side of the column 4. It includes a first photographing section 10 attached thereto, and a second photographing section 100 attached to the column 4 so as to extend horizontally from the other side of the column 4. When subject A is to undergo X-ray imaging such as CT imaging, for example, he stands with his head B positioned in the central space S of the first imaging unit 10 . When subject A is undergoing X-ray imaging such as cephalometric imaging, for example, he stands with his head B positioned in the central space Sa of the second imaging unit 100. Note that the posture of the subject A is not limited to a standing state, but may be a seated state.

The upper frame 11 that supports the X-ray generation section 20 and the X-ray detection section 30 of the first imaging section 10 and the upper frame 104 that supports the X-ray detection section 101 of the second imaging section 100 both extend horizontally. At the same time, they are bent so as to protrude on the same side with respect to an imaginary vertical plane that includes the center line of the support column 4. As a result, the support 4 is not located between the first imaging section 10 and the second imaging section 100, and the X-ray generation section 20 (rotated by the rotation drive section 19 described later) and the X-ray detection section 101 are However, they can now face each other without any obstacles between them.

The configuration of the first imaging section 10 will be explained with reference to FIGS. 1 to 3. The first photographing unit 10 has an upper frame 11 attached to the column 4 so as to extend horizontally from the column 4, and is attached to be rotatable (swivelable) around a central axis L extending perpendicularly to the upper frame 11. A rotating arm 12 is provided. The upper frame 11 and the swing arm 12 are movable in the vertical direction (Z-axis direction) by an upper frame elevating drive unit 13, which will be described later. An X-ray generating section 20 and an X-ray detecting section 30 are arranged at both ends of the horizontally extending rotating arm 12. The swing arm 12 includes a horizontal arm 12a attached to the upper frame 11 via a rotating shaft 12d, a first housing 12b connected to a first end of the horizontal arm 12a and hanging from the horizontal arm 12a, and a horizontal arm 12a. and a second housing 12c connected to the second end of the horizontal arm 12a and hanging down from the horizontal arm 12a. These horizontal arm 12a, first housing 12b, and second housing 12c are integrally molded. The swing arm 12 has an overall U-shape (or C-shape) that is open downward. A central space S in which the head B of the subject A is positioned is formed between the first housing 12b and the second housing 12c.

As shown in FIG. 3, the first photographing unit 10 includes an upper frame elevating drive unit 13 that moves the upper frame 11 and the swing arm 12 in the vertical direction (vertical direction) with respect to the support column 4. The support column 4 has a pair of parallel rails 6 that extend in the vertical direction. The upper frame 11 includes a base portion 11a (upper frame base portion) attached to the rail 6 of the support column 4, and an arm portion 11b (upper frame arm) extending horizontally from the base portion 11a and having the above-described swing arm 12 attached thereto. Department). The base portion 11a is fitted into the rail 6 of the support column 4 via a plurality of rollers 13d and is movable on the rail 6. The upper frame elevating drive section 13 includes a motor 13a fixed to the lower end of the support column 4, a ball screw 13b arranged vertically and rotated by the motor 13a, and a ball screw 13b fixed to the lower end of the base section 11a. The nut 13c is screwed into the nut 13c. The upper frame elevating drive unit 13 is controlled by the drive control unit 57 of the control device 50 to move the upper frame 11 and the swing arm 12 in the vertical direction (elevating).

The first photographing unit 10 includes a subject holder 40 that holds the subject A so that the head B of the subject A is located in the central space S. In the first imaging unit 10, the head B of the subject A is irradiated with X-rays. The subject holder 40 includes a head support part 40H so that the head B of the subject A can be held without moving as much as possible. The head support section 40H includes a chin rest 43, a head holder 44, and the like. The head B of the subject A in the central space S is positioned such that the front surface (face) of the head B faces the second imaging unit 100 (the second housing 12c shown in FIGS. 1 and 2).

Here, the XYZ orthogonal coordinate system will be explained. The XYZ orthogonal coordinate system is an orthogonal coordinate system defined in a three-dimensional space in which the X-ray imaging apparatus main body 2 is installed. The Z-axis direction is parallel to the axial direction of the rotating shaft 12d. In this embodiment, the axial direction of the rotating shaft 12d and the vertical direction of the swing arm 12 match and are parallel to the Z-axis direction. The Y-axis direction is perpendicular to the Z-axis direction. The X-axis direction is orthogonal to both the Z-axis direction and the Y-axis direction. In this specification, the Y-axis direction is the front-rear direction of the head B set on the head support part 40H. The X-axis direction is the left and right direction of the head B set on the head support section 40H. In this specification, the Z-axis direction may be referred to as the Z direction, the Y-axis direction as the Y direction, and the X-axis direction as the X direction.

In this specification, the direction from the head B toward the base 3, ie, the lower side, is the -Z side, and the direction from the head B away from the base 3, ie, the upper side, is the +Z side. The front of head B is the +Y side, and the back of head B is the -Y side. The right side of head B is the +X side, and the left side is the -X side.

The xyz orthogonal coordinate system is an orthogonal coordinate system defined in the rotating arm 12 that constitutes an imaging system that performs X-ray generation and X-ray detection. The xyz orthogonal coordinate system rotates around the rotation axis 12d. The z-axis direction is the axial direction of the rotating shaft 12d, and coincides with the Z-axis direction in the XYZ orthogonal coordinate system. The y-axis direction is perpendicular to the z-axis direction. The x-axis direction is orthogonal to both the z-axis direction and the y-axis direction. In this specification, the y-axis direction is the direction in which the X-ray detection section 30 and the X-ray generation section 20 face each other. The x-axis direction is a direction perpendicular to the y-axis direction and the z-axis direction. When the swing arm 12 rotates around the rotation axis 12d, the xyz orthogonal coordinate system rotates around the Z axis with respect to the XYZ orthogonal coordinate system. In this specification, the z-axis direction is sometimes referred to as the z direction, the y-axis direction as the y-direction, and the x-axis direction as the x-direction.

In this specification, the X-ray detection section 30 side is the +y side, and the X-ray generation section 20 side is -y. The right side from the -y side to the +y side is the +x side, and the left side from the -y side to the +y side is the -x side. The upper side in the vertical direction is the +z side, and the lower side is the -z side.

Which coordinate in the XYZ orthogonal coordinate system corresponds to the coordinate in the xyz orthogonal coordinate system can be specified by calculation. Trigonometric functions or two-dimensional coordinate calculations may be used for the calculation. For example, assume that when the swing arm 12 is at the reference position, the position of the zero point (x0, y0, z0) in the xyz orthogonal coordinate system matches the position of the zero point (X0, Y0, Z0) in the XYZ orthogonal coordinate system. be done. It is assumed that the reference point (x1, y1, z1) in the xyz orthogonal coordinate system is located at the same position as the coordinate (X1, Y1, Z1) in the XYZ orthogonal coordinate system. Under this assumption, it is assumed that the pivot arm 12 pivots by an angle α. It is assumed that the reference point (x1, y1, z1) after turning is located at coordinates (X2, Y2, Z2) in the XYZ orthogonal coordinate system. The coordinates (X2, Y2, Z2) are each expressed by the following formula.
X2=x1cosα+y1sinα
Y2=-x1sinα+y1cosα
Z2=z1

Note that when the horizontal movement drive section 18 (to be described later) moves the rotating shaft 12d in the X-axis direction or moves the rotating shaft 12d in the Y-axis direction, calculations are performed in which the movement component is added. Even when movement of the swing arm 12 in the Z-axis direction by the upper frame elevating drive section 13 occurs, calculations are performed in which the movement component is added.

Various amounts of movement of the swing arm 12 can be detected as appropriate. For example, a stepping motor may be used as the drive motor for the drive mechanism 7. By detecting the amount of drive, the amount of turning, horizontal movement, or vertical movement can be detected. Other position sensing devices may also be used.

Using the above configuration, the XYZ orthogonal Position calculations can be performed in a coordinate system. Even when the rotating arm 12 moves to perform various types of X-ray photography, the positional information of each point in the image reflected in the X-ray image can be used for calculations in the XYZ orthogonal coordinate system.

A configuration related to X-ray irradiation and X-ray detection of the first imaging unit 10 will be described with reference to FIGS. 1 and 3. The first imaging unit 10 is configured to be able to perform X-ray imaging in various imaging modes. Thereby, the first imaging unit 10 outputs an X-ray detection signal for a CT image (tomographic image) by performing CT imaging of all or part of the head B. The first photographing unit 10 outputs an X-ray detection signal for a projection image by X-ray photographing all or part of the head B. In this embodiment, the projected image is, for example, a scout image. The projected image may be a two-directional scout image that is a projected image obtained by taking X-rays from two different directions, and the X-ray shape adjustment unit 22 regulates the X-rays into a vertically elongated slit X-ray beam. The image may be a panoramic image that is a tomographic image obtained by rotating the X-ray generating section 20 and the X-ray detecting section 30.

The first imaging unit 10 includes an X-ray generation unit 20 for irradiating the head B of the subject A with X-rays, and an X-ray detection unit 30 for detecting the X-rays that have passed through the head B. The X-ray generator 20 is provided at the first end of the swing arm 12. The X-ray detection section 30 is provided at the second end of the swing arm 12. The X-ray generating section 20 and the X-ray detecting section 30 face each other substantially horizontally so that a central space S is located between the X-ray generating section 20 and the X-ray detecting section 30.

The X-ray generator 20 includes the above-described first housing 12b, an X-ray generator 21 housed in the first housing 12b, and an X-ray shape adjustment device located adjacent to the X-ray generator 21. 22. The X-ray generator 21 has an X-ray tube 21a, and irradiates X-rays toward the central space S (that is, toward the head B) from a focal point 21b. The X-ray shape adjustment section 22 includes a plurality of shielding members installed vertically so as to face the X-ray tube 21a, and a moving mechanism that moves these shielding members. The plurality of shielding members are installed so as to partially overlap each other, and an opening having a certain size is formed between the shielding members. By moving the shielding member by the moving mechanism, the size of the opening can be freely changed (adjusted).

Here, scout imaging is preliminary X-ray imaging to capture a positioning image in order to perform another imaging, such as CT imaging. The positioning image is called a scout image. In contrast to preliminary scout imaging, X-ray imaging such as CT imaging is called main imaging. Scout photography is carried out for the purpose of conducting actual photography.

Examples of scout photography include two-directional scout photography and panoramic scout photography. In two-directional scout photography, a first scout photography is performed from a first direction, and a second scout photography is performed from a second direction. In panoramic scout photography, panoramic photography is performed. If a panoramic image obtained by panoramic imaging performed as main imaging in the X-ray imaging apparatus main body 2 is originally stored, the panoramic image may be used as a panoramic scout image. Panoramic imaging in this case is comparatively preliminary imaging compared to CT imaging, which is the actual imaging.

For example, when acquiring a CT image (that is, during CT imaging), the X-ray shape adjustment unit 22 forms a cone beam (CB) that spreads in the shape of a truncated quadrangular pyramid (for example, a truncated square pyramid). The shape of the X-rays making up the cone beam can be any kind of frustum. The shape of the cone beam may be a truncated cone shape whose cross section perpendicular to the X-ray irradiation direction is a circle, or may be another frustum shape whose cross section is a different shape. The size of the cone beam is also changed (adjusted) as appropriate depending on the size of the irradiation field. Further, when acquiring a projection image such as a two-directional scout image, that is, a scout image, the X-ray shape adjustment unit 22 forms a frustum-shaped cone beam similar to that during CT imaging.

Two-directional scout photography is performed by one-shot photography using a simple projection using a cone beam. In two-direction scout photography, one-shot photography is performed from one direction, and one-shot photography is performed from another direction. The spread of the cone beam may be wider than that during CT imaging. Regarding the X-ray irradiation range, there are restrictions based on the width of the detection surface of the X-ray detector 31 and restrictions based on the need to avoid unnecessary X-ray irradiation to the subject A depending on the purpose of imaging. be. Considering these constraints, the cone beam spread may be adjusted accordingly. When capturing a two-directional scout image, the rotation arm 12 may be controlled to move so that the X-ray detector 31 approaches the head B more closely than during CT imaging. That is, the X-ray detector 31 may be moved to the −y side compared to when CT imaging is performed. With this control, the magnification rate of the head image is reduced, and a wider range is reflected in the image. This control is possible by controlling the horizontal movement of the swing arm by a horizontal movement drive unit 18, which will be described later. Instead of one-shot imaging, a slit beam may be formed that extends in the z direction and spreads out in the shape of a vertically elongated truncated quadrangular pyramid, and the range necessary for acquiring the scout image may be scanned from one side to the other.

During panoramic imaging, the X-ray shape adjustment section 22 forms a slit beam that extends in the z direction and spreads out into a vertically elongated quadrangular truncated pyramid shape. For irradiation in the y direction, the drive mechanism 7 rotates the rotation arm 12 so that the slit beam is incident as perpendicularly to the irradiation target location on the dental arch row. The dental arch is scanned from one side to the other.

The specific configuration of the X-ray shape adjustment unit 22 may be a configuration including a plurality of shielding members as described above (for example, see Japanese Patent Application Laid-open No. 2019-37393), but other known aperture mechanisms (collimators, etc.) may be used. ). The X-rays generated in the X-ray generating section 20 are formed into an X-ray beam by the X-ray shape adjusting section 22. This X-ray beam includes the above-mentioned cone beam and slit beam.

The X-ray detection unit 30 includes the second casing 12c described above, an outer casing 16 fitted into the second casing 12c from below, and an X-ray detector housed inside the second casing 12c and the outer casing 16. It has a line detector 31. The X-ray detector 31 detects the X-rays emitted from the X-ray generator 20, irradiated onto the head B, and transmitted through the head B. The X-ray detector 31 is constituted by, for example, a flat panel detector (FPD) having a detection surface extending in a planar manner, an X-ray fluorescence intensifier tube, or the like. A plurality of detection elements arranged on the detection surface of the X-ray detector 31 convert the intensity of incident X-rays into electrical signals. The electrical signal is input to the control device 50 (or information processing device 70) as an output signal, and an X-ray image is generated based on the signal.

In the first imaging unit 10 of the X-ray imaging apparatus main body 2, the upper frame 11 and the rotating arm 12 are arranged so that the central space S where the head B is placed is located between the X-ray generator 21 and the X-ray detector 31. It is a support part that supports the X-ray generator 21 and the X-ray detector 31 so that the X-ray generator 21 and the X-ray detector 31 are supported.

The X-ray detector 30 is a detector lifter configured to move the height (position in the Z-axis direction) of the X-ray detector 31 with respect to the second housing 12c (upper frame 11 and rotating arm 12). A drive section 33 is provided. The cylindrical second casing 12c is open downward, and one cylindrical outer casing 16 is open upward. The outer housing 16 is slidable in the vertical direction (Z-axis direction) with respect to the second housing 12c. The detector lift drive unit 33 includes a motor 33a fixed to the lower end of the second housing 12c, a ball screw 33b arranged in the vertical direction (Z-axis direction) and rotated by the motor 33a, and an X-ray detector. 31 (opposite side to the detection surface) and into which a ball screw 33b is screwed. The ball screw 33b may be rotatably supported by the second housing 12c by some kind of support member attached to a location away from the range of movement of the nut 33c. The nut 33c and the X-ray detector 31 are provided with a mechanism (rotation stop) for preventing rotation around the Z-axis. When the ball screw 33b rotates around the rotation axis extending in the vertical direction, the nut 33c moves up and down together with the X-ray detector 31.

Two sets of motors 33a and ball screws 33b may be attached to the second housing 12c, and two sets of nuts 33c may be attached to the back side of the X-ray detector 31. Each element is placed at the same height. A plurality of ball screws 33b may be installed in parallel and rotated synchronously. As a result, the plurality of nuts 33c move up and down synchronously. Regarding the motor 33a, the ball screw 33b, and the nut 33c, the detailed structures are not particularly limited as long as the parts that move up and down can be prevented from rotating. One motor 33a may be omitted, and a guide member and a guided member may be used instead of one ball screw 33b and nut 33c. For example, a rod-shaped guide member may be fixed to the second housing 12c instead of the ball screw 33b, and a guided member having a guided portion such as a bore may be fixed to the X-ray detector 31 instead of the nut 33c. good. A guided portion of the guided member fits into the guide member. The guide member and the guided member constitute an elevating guide mechanism without a driving function, in which the guided member moves up and down with low resistance relative to the guide member. In this case, the lifting and lowering drive may be performed by only one motor 33a, ball screw 33b, and nut 33c. The detector elevation drive section 33 is controlled by the drive control section 57 of the control device 50 to move the X-ray detector 31 vertically relative to the upper frame 11 and the rotating arm 12 (moves it up and down).

The detector lifting/lowering drive section 33 further includes a spring 17 that engages with the second housing 12c and the outer housing 16. The spring 17 is, for example, a tension coil spring. A first end of the spring 17 is connected to the upper end of the second housing 12c, and a second end of the spring 17 is connected to the upper end of the outer housing 16. Thereby, the spring 17 applies a biasing force to the outer casing 16 to pull the outer casing 16 upward. The lower end of the X-ray detector 31 is in contact with the bottom surface of the outer housing 16. When the X-ray detector 31 is moved downward by the detector lifting/lowering drive unit 33, the outer housing 16 is pushed by the lower end of the X-ray detector 31 and lowers against the force pulled by the spring 17. When the X-ray detector 31 is moved upward by the detector lift drive section 33, the outer casing 16 is pulled upward by the restoring force of the spring 17. As a result, the outer casing 16 that contacts the lower end of the X-ray detector 31 rises to follow the rising X-ray detector 31.

Next, a drive mechanism for horizontally moving and rotating the X-ray generating section 20 and the X-ray detecting section 30 will be described with reference to FIGS. 3, 4, and 5. As shown in FIGS. 3, 4, and 5, the first photographing section 10 is mounted in the arm section 11b of the upper frame 11, and is horizontally movable by moving the rotating shaft 12d in the X-axis direction and the Y-axis direction. A drive unit (two-dimensional movement drive unit) 18 is provided. The horizontal movement drive unit 18 moves the rotating shaft 12d in the X-axis direction and the Y-axis direction, thereby moving the swing arm 12 in the X-axis direction and the Y-axis direction. The horizontal movement drive section 18 includes a table 18a and a horizontal movement motor 18b for horizontally moving the table 18a. The table 18a includes an X table 18x to which the upper end of the rotating shaft 12d is fixed, and a Y table 18y arranged above the X table 18x. The horizontal movement motor 18b includes an X-axis movement motor 18c that moves the X-table 18x, and a Y-axis movement motor 18d that is fixed within the arm portion 11b and moves the Y-table 18y. The X table 18x is attached to the Y table 18y via a guide member, and is slidable within a certain range in the X-axis direction with respect to the Y table 18y. The X-axis moving motor 18c is fixed to the Y-table 18y and drives the X-table 18x to move in the X-axis direction. The Y table 18y is attached to the arm portion 11b via a guide member, and is slidable within a certain range in the Y-axis direction with respect to the arm portion 11b. The Y-axis moving motor 18d is fixed to the arm portion 11b and drives the Y-table 18y to move in the Y-axis direction.

The X-axis movement motor 18c and the Y-axis movement motor 18d are controlled by the drive control section 57 of the control device 50 to move the X table 18x and the Y table 18y, respectively. The X table 18x moves the rotating shaft 12d (swivel arm 12) in the lateral direction (X-axis direction) by the X-axis moving motor 18c. The Y-table 18y moves the rotating shaft 12d (swivel arm 12) in the front-rear direction (Y-axis direction) by moving the X-table 18x in the Y-axis direction using the Y-axis moving motor 18d. The X table 18x moves in the Y-axis direction as the Y table 18y moves.

The first imaging unit 10 includes a swing drive unit 19 that is mounted in the horizontal arm 12a of the swing arm 12 and swings the swing arm 12 around the center axis L of the rotation shaft 12d. The swing drive unit 19 includes a swing motor 19b fixed within the horizontal arm 12a, and a belt 19c that spans the output shaft of the swing motor 19b and the lower end of the rotating shaft 12d. A bearing 19d is interposed between the rotating shaft 12d and the horizontal arm 12a. The bearing 19d includes an inner ring and an outer ring. The bearing 19d supports the rotating shaft 12d with its inner ring, and supports the horizontal arm 12a with its outer ring. The horizontal arm 12a (swivel arm 12) rotates smoothly about the rotation axis 12d. The swing motor 19b is controlled by the drive control unit 57 of the control device 50 to rotate the horizontal arm 12a (swivel arm 12) around the central axis L.

The rotation axis RCT around which the X-ray generator 21 and the X-ray detector 31 rotate can be set by the following steps (i) to (iv). Examples of this setting are shown in FIGS. 18 to 20, which are plan views of the swing arm 12 from the Z direction. Note that although the internal structures of the X-ray generator 21, the X-ray detector 31, etc. are shown in FIGS. 18 to 20, some portions are shown with solid lines to make the figures easier to read.
(i) The axis of the rotating shaft 12d is defined as an axis 12dc (the position of this axis 12dc coincides with the above-mentioned central axis L).
(ii) The swing drive unit 19 causes the swing arm 12 to swing around the axis 12dc. This turn is referred to as a first turn.
(iii) The horizontal movement drive unit 18 causes the rotating shaft 12d to rotate around the axis AX. This turning will be referred to as a second turning.
(iii-a) A calculation axis AX extending in the Z-axis direction is temporarily set between the X-ray generator 21 and the X-ray detector 31.
(iii-b) The axis AX may be located at the same location as the axis 12dc, as illustrated in FIG. 18, or may be located away from the axis 12dc, as illustrated in FIG. 19 or 20. good.
(iii-c) Axis line AX is shown in FIG. 18 or FIG. As illustrated, it may be on the line GD, or as illustrated in FIG. 20, it may be deviated from the line GD in the +x-axis direction or the -x-axis direction. In the examples shown in FIGS. 18 to 20, the X-ray shape adjustment unit 22 forms the X-ray beam XB such as the X-ray cone beam CB so that the center beam and the line GD coincide in position with respect to the spread in the x direction. The degree of opening of the aperture through which the X-rays are passed is set.
(iii-d) If the axis AX is at the same location as the axis 12dc, the second turn is not performed and only the first turn is performed. The X-ray generator 21 and the X-ray detector 31 rotate about the axis 12dc as a rotation center. That is, the X-ray generator 21 and the X-ray detector 31 rotate around the rotation axis RCT, with the rotation axis RCT placed on the axis 12dc.
(iii-e) When the axis AX is located away from the axis 12dc, the first turn and the second turn are executed. The first pivot and the second pivot are performed as synchronous pivot movements of the same angle. The X-ray generator 21 and the X-ray detector 31 rotate around the rotation axis RCT, with the axis AX as the rotation center, that is, the rotation axis RCT is placed on the axis AX.
(iv) Through the above steps, the rotation axis RCT is set at an arbitrary position within the mechanical constraints and geometric constraints in the XYZ orthogonal coordinate system by controlling the rotation drive unit 19 and the horizontal movement drive unit 18. be done.

Note that for control when the axis AX is located at the same location as the axis 12dc, it is sufficient to execute the first turn, so the calculation for setting the axis AX does not necessarily need to be performed. The calculation for setting the axis AX may be omitted. It can also be considered that the second turning is performed when the axis AX is at the same location as the axis 12dc. In other words, although the second turning is performed, it can be considered that the amount of turning (momentum) is zero. In most cases, X-ray photography is performed by rotating the X-ray generator 21 and the X-ray detector 31 around the rotation axis RCT as described above. be exposed. CT imaging can also be performed with high precision by such rotation. As illustrated in FIG. 18 or 19, when the axis AX is on the line GD, it is applicable to a normal CT scan in which the X-ray beam is not offset with respect to the imaging area. As illustrated in FIG. 20, when the axis AX deviates from the line GD in the +x-axis direction or the -x-axis direction, it is possible to apply an offset CT scan in which the X-ray beam is offset with respect to the imaging region.

Incidentally, in FIG. 18, during CT imaging of the target area FOV1, the rotating arm 12 performs a rotating movement at an angle θ1 (90° clockwise in plan view) around the axis AX (axis 12dc) placed at the center of the FOV1. It is shown. In FIG. 19, during CT imaging of the target area FOV2, the rotating arm 12 rotates at the same rotating angle (synchronized) as it performs a rotating movement of angle θ2 (90° clockwise in plan view) around the axis 12dc. It is shown that the axis 12d performs a turning movement at an angle θ3 (90° clockwise in plan view) around the axis AX placed at the center of the FOV2. In FIG. 19, during CT imaging of the target area FOV3, the rotating arm 12 performs a rotating movement of θ4 (90° clockwise in plan view) around the axis 12dc at the same rotating angle (synchronized). 12d is shown rotating at an angle θ5 (90° clockwise in plan view) around the axis AX placed at the center of FOV3.

As shown in FIG. 6, in the first imaging unit 10, an X-ray generator 21 and an ) is provided with a drive mechanism 7 configured to move an X-ray generator 21 and an X-ray detector 31 by driving an upper frame 11 and a rotating arm 12, which are supporting parts, so as to take an X-ray image. This drive mechanism 7 includes the above-mentioned upper frame elevating drive section 13, horizontal movement drive section 18, and rotation drive section 19.

As shown in FIG. 1, the first photographing unit 10 further includes a lower frame 41, the above-mentioned subject holder 40 that holds the subject A so that the head B of the subject A is located in the central space S, and the above-mentioned A subject holder lifting/lowering drive section 46 is provided for moving the subject holder 40 in the vertical direction (vertical direction) with respect to the upper frame 11. The lower frame 41 has a base portion 41a (lower frame base portion) attached to the rail 6 of the support column 4, and an arm portion 42 (lower frame arm portion) extending horizontally from the base portion 41a. A subject holder 40 is provided on the arm portion 42 . In this embodiment, the subject holder 40 includes a head support section 40H. The head support section 40H includes a chin rest 43 on which the chin of the subject A is placed, and a head holder 44 that holds the head B of the subject A from the side. The chin rest 43 stands up from the tip of the arm portion 42 toward the central space S. The head holder 44 includes a pair of rod portions 44a and an abutment member 44b that abuts the head B. The rod portion 44a stands up from the arm portion 42 toward the central space S. A first end of the rod portion 44a is connected to the arm portion 42, and an abutting member 44b is provided at a second end of the rod portion 44a. The base portion 41a is fitted into the rail 6 of the support column 4 via a plurality of rollers 46d and is movable on the rail 6.

The subject holder elevating drive unit 46 includes a motor 46a fixed to a base part 41a, a ball screw 46b arranged vertically and rotated by the motor 46a, and a ball screw 46b fixed to the base part 11a of the upper frame 11. and a nut 46c that is screwed into the nut 46c. The subject holder elevation drive section 46 is controlled by the drive control section 57 of the control device 50 to move the subject holder 40 in the vertical direction with respect to the upper frame 11 (moves it up and down). Note that, as shown in FIG. 1, the subject holder 40 may include a grip 47 that can be held by the hand of the subject A. When the X-ray imaging apparatus main body 2 is configured as a sitting type in which the subject A is seated, the subject holder 40 may further include a chair.

The upper frame 11 and the rotating arm 12 are raised and lowered by the upper frame elevating drive section 13 so that the height of the chin rest 43 of the subject holder 40 approximately matches the height of the chin of the naturally standing subject A, for example. At this time, the height of the chin rest 43 may be finely adjusted by moving the subject holder 40 using the subject holder elevating drive section 46. Thereafter, with the head B of the subject A fixed on the head support part 40H, the upper frame 11 and the rotating arm 12 are raised or lowered by the upper frame elevating drive part 13, and at the same time, the upper frame 11 and the rotating arm 12 are raised or lowered by the subject holder elevating drive part 46. The subject holder 40 is lowered or raised. The speed and amount of movement of the upper frame 11 and the rotating arm 12 and the lowering/lowering of the subject holder 40 are controlled to be synchronized. Control is performed by the drive control unit 57 so that the distance by which the swing arm 12 is raised or lowered is equal to the distance by which the subject holder 40 is lowered or raised. Through this control, the rotation arm 12 is moved relative to the head B while maintaining the height of the chin rest 43, the height of the head holder 44, the height of the subject holder 40, and the height of the head B constant. to raise and lower. As a result, the location of X-ray irradiation on the head B can be changed in the vertical direction (Z-axis direction). In this way, the rotating arm 12 and the subject holder 40 can each independently slide in the vertical direction.

The specific configurations of the upper frame elevation drive unit 13, horizontal movement drive unit 18, rotation drive unit 19, detector elevation drive unit 33, and subject holder elevation drive unit 46 are not limited to those described above. The drive mechanism is not limited to a configuration using a ball screw and a nut, and may be a drive mechanism equipped with, for example, a rotating roller and a belt. Both the horizontal movement drive section 18 and the rotation drive section 19 may be mounted within the arm section 11b of the upper frame 11. Both the horizontal displacement drive 18 and the pivot drive 19 may be mounted within the horizontal arm 12a of the pivot arm 12. One of the horizontal movement drive unit 18 and the swing drive unit 19 may be mounted within the arm portion 11b of the upper frame 11, and the other may be mounted within the horizontal arm 12a of the swing arm 12.

The configuration related to cephalometric imaging will be described with reference to FIGS. 1 and 2. As shown in FIGS. 1 and 2, the second imaging section 100 includes an X-ray detection section 101, a slit mechanism 102, and a head fixture 103. When cephalometric imaging is performed, the X-ray detection section 30 is not located between the X-ray generation section 20 and the X-ray detection section 101; The swing arm 12 is rotated so that the X-ray detection unit 101 is not located on the connecting line.

In the state shown in FIGS. 1 and 2, the X-ray detection unit 101 is located at the end of the X-ray imaging apparatus main body 2 in the +Y direction. Therefore, the X-ray detecting section 30 and the support column 4 are arranged so that the X-ray generating section 20 is located as far as possible in the -Y direction, and from the X-ray irradiation path between the X-ray generating section 20 and the X-ray detecting section 101. The swing arm 12 rotates so that both are in the retracted position and stops at the desired position. If the swing arm 12 is viewed from above and the 12 directions are likened to the time on a clock, the +Y direction is 12 o'clock, the -Y direction is 6 o'clock, the +X direction is 3 o'clock, and the -X direction is Assume that it is 9 o'clock. It is assumed that the X-ray generating section 20 is located at approximately 6 o'clock direction and the X-ray detection section 30 is located at approximately 12 o'clock direction with respect to the rotation axis 12d. Since the X-ray detection section 101 is located at approximately the 12 o'clock direction, the X-ray detection section 30 will block the X-ray irradiation path between the X-ray generation section 20 and the X-ray detection section 101 if this continues. Therefore, if the positions of the X-ray generating section 20 are adjusted to be approximately at 7 o'clock or 8 o'clock, and the X-ray detection section 30 is approximately at 1 or 2 o'clock, centering on the rotation axis 12d, the X-ray Elements that block the X-ray irradiation path between the generating section 20 and the X-ray detecting section 101 can be eliminated. In addition, with this configuration, the distance (specifically For example, it is possible to shorten the length of the arm portion 11b while maintaining the length (165 cm). As a result, the size of the X-ray imaging apparatus main body 2 can be made compact.

The first housing 12b is configured to be rotatable relative to the horizontal arm 12a around a rotation axis parallel to the Z-axis direction. During cephalometric imaging, the first housing 12b is positioned relative to the horizontal arm 12a so that the X-ray detection section 101 of the second imaging section 100 faces the X-ray generator 21 of the X-ray generation section 20 via the slit mechanism 102. be rotated. Cephalometric imaging is performed on the head B of the subject A fixed on the head fixture 103.

The head fixture 103 is a device for positioning the head B, and includes, for example, a pair of rod-shaped members. The head fixing device 103 has ear rods that position both ears by inserting the tips of these rod-like members into the ears on both sides of the head B, and the head fixing device 103 that comes into contact with the forehead of the head B and fixes the head. and a forehead rod for positioning the section.

The slit mechanism 102 includes a slit member in which a slit extending in the vertical direction (vertical direction) is formed, and a movement mechanism that moves the slit member in the horizontal direction. The X-rays are formed by the shielding member of the X-ray shape adjustment section 22 into a slit beam that spreads out in the shape of a vertically long truncated quadrangular pyramid. That is, the shielding member of the X-ray shape adjustment section 22 forms a slit to form a slit beam. During cephalometric imaging, the shielding member of the X-ray shape adjustment section 22 moves in the horizontal direction, so that the slit moves in the horizontal direction. Among the X-rays emitted from the X-ray generator 21, the X-rays are further regulated by the slit of the slit mechanism 102, and the X-rays that have passed through the slit member are irradiated onto the head B fixed to the head fixture 103. In cephalometric imaging, the slit formed by the X-ray shape adjustment section 22 moves in the horizontal direction, and in synchronization with this, the slit member (i.e., slit) of the slit mechanism 102 moves in the same direction. is scanned by X-rays. In addition, a configuration is adopted in which the detection surface of the X-ray detector 101D is widened, the regulation amount of the X-ray shape adjustment unit 22 and the regulation amount of the slit mechanism 102 are made small, and one-shot imaging is performed with a wide X-ray cone beam. may be done.

The X-ray detector 101 includes an X-ray detector 101D having the same configuration as the X-ray detector 31. This X-ray detector detects X-rays that have passed through the head B positioned by the head fixture 103. The X-ray detector is configured to move the detection surface parallel to the movement direction of the slit member of the slit mechanism 102 in the horizontal direction. The X-ray detector detects the X-rays that have passed through the slit and transmitted through the head MH. The moving direction of the slit mechanism 102 and the detection surface is perpendicular to the straight line connecting the X-ray generator 21 and the center of the head fixture 103, and is horizontal.

A plurality of detection elements arranged on the detection surface of the X-ray detector 101D convert the intensity of incident X-rays into electrical signals. The electrical signal is input to the control device 50 (or information processing device 70) as an output signal, and a cephalometric image is generated based on the signal. In the following description, control and information processing between the control device 50, the information processing device 70, and the second imaging unit 100 will be omitted.

Next, with reference to FIG. 6, the control device 50 included in the X-ray imaging apparatus main body 2 will be described. The control device 50 controls X-ray imaging in the first imaging section 10 and the second imaging section 100. The control device 50 is installed at an appropriate location in the main body 2 of the X-ray imaging apparatus. The control device 50 may be installed inside the arm portion 42 of the lower frame 41, for example. The control device 50 may be installed somewhere within the swing arm 12, for example inside the X-ray detection section 30. The control device 50 includes an information processing section 51, a display section 50a, a storage section 52, an interface 53, and an operation section 50b. The control device 50 is a computer device that includes a processor (eg, CPU, etc.), memory (eg, ROM, RAM, etc.), and the like. The information processing section 51 includes an image processing section 54, a mode setting section 55, a shooting area setting section 56, a drive control section 57, and a shooting control section 58 as functional elements.

The display unit 50a displays the image generated by the image processing unit 54. The display unit 50a is provided, for example, on the operation panel 90 as a display. The display section 50a may be configured with a touch panel so that the display section 50a receives operations. In this case, the display section 50a also serves as the operation section 50b. The display on the display unit 50a may include not only a visual display but also an auditory display and/or a tactile display such as vibration. The storage unit 52 stores control programs and the like. The control device 50 communicates information with each of the first imaging unit 10, the second imaging unit 100, the information processing device 70, and the operation panel 90 via an interface 53 by wire or wirelessly. The operation unit 50b includes input means such as a mouse or a keyboard, and accepts operations related to X-ray photography, for example, by an operator. The operation section 50b outputs a control signal to the photographing area setting section 56, the drive control section 57, the photographing control section 58, etc. according to the operation content. Note that the display unit 50a may be configured to be able to display an X-ray image generated by the information processing device 70. The display unit 50a may have the function of a user interface by displaying an X-ray image and displaying a cursor or the like for specifying a position with respect to the X-ray image (for example, a scout image).

The image processing unit 54 can generate various images, but for example, it generates an image related to control of X-ray photography. Examples of images related to control include images of mode setting screens, imaging condition setting images such as tube current and tube voltage, and positioning images. An example of an image for positioning is a schematic diagram simulating a dental arch in which the imaging area of CT imaging is displayed with a circular index. By moving the relative position of the circular index with respect to the schematic diagram of the dental arch, the position of the rotating arm 12 is adjusted, and the configuration is configured such that the position indicated by the circular index becomes the actual CT imaging area. Ru. Alternatively, for example, an image of a mode setting screen may be generated.

The mode setting section 55 sets the imaging mode in the first imaging section 10 based on the operator's operation input on the operation panel 90. A mode setting screen for selecting a shooting mode is displayed on the operation panel 90. On the mode setting screen, for example, shooting modes such as two-directional scout shooting, panoramic scout shooting, or CT shooting are displayed. In this embodiment, the automatic shooting mode is displayed on the mode setting screen. This automatic imaging mode means, for example, after performing scout imaging such as two-directional scout imaging to obtain a scout image, a target area for CT imaging (a third area or region of interest to be described later) is determined based on the scout image. In this mode, the target area is CT-photographed. Buttons corresponding to each imaging mode are displayed on the mode setting screen of the operation panel 90, and when the operator presses one of the buttons, the mode setting section 55 selects the imaging mode corresponding to the pressed button. Set the mode. When the automatic shooting mode button is pressed, either two-directional scout shooting or panoramic scout shooting may be set on the operation panel 90. The mode setting unit 55 transmits a signal indicating the set shooting mode to the information processing device 70 via the interface 53.

The imaging area setting unit 56 receives an operation input by the operator, and sets an imaging area according to the content of the operation. For example, the imaging area setting unit 56 causes the display unit 50a to display an area setting screen that matches the imaging mode set by the mode setting unit 55, and sets the imaging area based on the operation input performed on the screen. do. When the automatic shooting mode is selected, the shooting area setting unit 56 sets the area of the shooting target output from the information processing device 70 (specifically, the coordinates corresponding to the shooting direction and shooting range in scout shooting, the coordinates corresponding to the shooting direction and shooting range in CT shooting, coordinates of the center position, etc.) and outputs a signal indicating the imaging area to the drive control section 57 and the imaging control section 58. Note that when the imaging area is manually input via the operation unit 50b, the imaging area setting unit 56 inputs the area of the imaging target output from the operation unit 50b (accepting position designation), and sets the imaging area. A signal indicating the area is output to the drive control section 57 and the photographing control section 58.

When performing positioning using a scout image, when the position setting for the scout image is performed in the information processing device 70, information on the set area to be photographed is sent from the information processing device 70 to the photographing area setting unit 56. . When the imaging area setting unit 56 receives information about the area to be imaged, it outputs a signal indicating the imaging area to the drive control unit 57 and the imaging control unit 58. The fact that the position setting has been performed may be displayed on the display section 50a, and X-ray imaging may be executed by accepting an operation using the X-ray irradiation operation section 92 (execution permission). The information processing device 70 may issue instructions up to the execution of X-ray photography. The configuration in which X-ray imaging is permitted on the X-ray imaging apparatus main body 2 side has the advantage that on-site safety confirmation can be made more reliably.

The drive control unit 57 controls the drive mechanism 7 of the first imaging unit 10 so that the first imaging unit 10 performs X-ray imaging of the imaging area output from the imaging area setting unit 56. When the automatic imaging mode is set in the mode setting unit 55, the drive control unit 57 receives information from the information processing device 70 and sets the first imaging mode so that, for example, X-ray imaging is performed sequentially according to a flow described later. 10.

The imaging control unit 58 controls the X-ray generation unit 20 and the X-ray detection unit 30 of the first imaging unit 10 in conjunction with the drive control unit 57, and receives X-rays from the X-ray detection unit 30 via the interface 53. Obtain the detection signal. The imaging control unit 58 outputs the acquired X-ray detection signal to the image processing unit 71i of the information processing device 70.

These imaging area setting unit 56, drive control unit 57, and imaging control unit 58 control the drive mechanism 7 to operate the X-ray generator 21 and the X-ray detector 31 so as to perform X-ray imaging in a predetermined imaging area. This is a control unit that moves the object.

The drive control section 57 and the imaging control section 58 horizontally irradiate the X-ray cone beam when the first imaging section 10 performs two-directional scout imaging (so-called horizontal irradiation). In horizontal irradiation, the center beam of the X-ray cone beam is irradiated from the −y side to the +y side without changing the height in the z direction. Note that at this time, the X-ray cone beam may be irradiated at other appropriate angles. In that case, coordinate calculations may be adjusted during positioning (scouting). For example, when performing scout imaging from the X direction in either the first or second scout imaging, it is conceivable to move the X-ray detection unit 30 closer to the head B than during CT imaging. When bringing the X-ray detection unit 30 close, so-called launch irradiation may be employed if it is possible to avoid contact or collision of the X-ray detection unit 30 with the shoulder of the subject A. The drive control unit 57 and the imaging control unit 58 control the X-ray generation unit 20 so that when the first imaging unit 10 performs panoramic scout imaging, the slit beam is irradiated at an inclination angle of, for example, 5 degrees with respect to the horizontal plane. and controls the X-ray detection section 30. The slit beam at this time is controlled to be tilted upward from the X-ray generator 21 toward the X-ray detector 31 (so-called launch irradiation). In launch irradiation, the center beam of the slit beam is tilted, for example, by 5 degrees in the +z direction with respect to a straight line from the -y side to the +y side. The drive control unit 57 and the imaging control unit 58 control the X-ray generation unit 20 and the X-ray detection unit 30 so that the central axis of the cone beam is directed horizontally when the first imaging unit 10 performs CT imaging. (so-called horizontal irradiation).

Next, with reference to FIG. 7, the information processing device 70 included in the X-ray imaging apparatus 1 will be described. The information processing device 70 performs image processing of the X-ray detection signal output from the X-ray imaging apparatus main body 2 side. In particular, when the information processing device 70 receives a signal from the control device 50 indicating that the automatic photographing mode has been set, the information processing device 70 executes various calculation processes and control processes related to the automatic photographing mode. The information processing device 70 includes an information processing section 71, a display section 70a, a storage section 72, an interface 73, and an operation section 70b. The information processing device 70 is a computer device including a processor (eg, CPU, etc.), memory (eg, ROM, RAM, etc.), and may be, for example, a workstation. The information processing section 71 includes an image processing section 71i, a photographing area setting section 71r, an acquisition section 74, a determination image generation section 75, a determination section 76, a coordinate calculation section 77, and a control section 78 as functional elements. The aforementioned control device 50 may be provided in the information processing device 70.

Note that, in FIG. 7, a determination model storage unit 79 and a server 200 are shown in order to explain determination processing using a determination model. However, these judgment model storage unit 79 and server 200 may be omitted. In the following explanation, the functions and processing when these are omitted will be explained first. Subsequently, an X-ray imaging system M including an information processing device 70 including a determination model storage section 79, a server 200, and the X-ray imaging apparatus main body 2 will be described.

The image processing unit 71i acquires the X-ray detection signal output from the X-ray imaging apparatus main body 2 through the interface 73, performs predetermined image processing, and generates X-ray image data and an X-ray image. The storage unit 72 stores X-ray image data and X-ray images generated by the image processing unit 71i. The storage unit 72 stores attribute information including ID information of the subject A, X-ray imaging conditions (information regarding imaging mode, date and time), etc. in association with the X-ray image data.

The image processing unit 71i inputs the X-ray detection signals output from the first imaging unit 10 and the second imaging unit 100, and performs predetermined image processing based on the X-ray detection signals to generate X-ray image data. and generate an X-ray image. The X-ray detection signals output from the first imaging section 10 and the second imaging section 100 may be configured such that they are once collected in the control device 50 and then enter the image processing section 71i via the control device 50. good.

For example, when CT imaging is performed in the first imaging unit 10, the image processing unit 71i performs pre-processing and filtering on a plurality of input projection image data (corresponding to "raw CT image data" to be described later). Perform processing, back projection processing, etc. Through these processes, the image processing unit 71i generates three-dimensional image data, specifically, three-dimensional volume data (corresponding to "visualized processed CT image data" described later), and extracts a section of interest from the three-dimensional data. CT image data (corresponding to "visualized CT image data" to be described later) of each sliced slice is generated. The data structure of such three-dimensional image data is volume data DT in which CT values are stored in a large number of voxels, as shown in FIG. 11, for example. When a scout image is photographed in the first photographing section 10, the image processing section 71i generates projection image data and a projection image based on the input X-ray detection signal. The image processing unit 71i generates two X-ray image data and two X-ray images when the first imaging unit 10 performs X-ray imaging from two different directions (irradiation angles). The two X-ray image data in this case are two-directional scout image data C1 and C2 (see FIG. 12). Further, when panoramic imaging is performed in the first imaging unit 10 and the slit beam of X-rays is irradiated so as to trace the curved surface corresponding to the dental arch from one end of the left and right to the other end, the image processing unit 71i X-ray image data for a panoramic scout image is generated by connecting the strip-shaped image data obtained by compositing or the like. The image processing unit 71i causes the display unit 70a to display the single generated panoramic image. The image data and images generated by the image processing section 71i are sent to the display section 70a for display and/or sent to the storage section 72 for storage.

The display unit 70a displays the X-ray image generated by the image processing unit 71i on a display or the like. The display on the display unit 70a may include not only a visual display but also an auditory display and/or a tactile display such as vibration. The storage unit 72 stores the X-ray image generated by the image processing unit 71i. The storage unit 72 may store attribute information including ID information of the subject A, X-ray imaging conditions (information regarding imaging mode, date and time), etc. in association with the X-ray image. The information processing device 70 communicates information with each of the first imaging unit 10, the second imaging unit 100, the control device 50, and the operation panel 90 via an interface 73, either by wire or wirelessly. The operation unit 70b may include input means such as a mouse or a keyboard, and may accept operations related to X-ray imaging by an operator, for example. Note that the display unit 70a may have the function of a user interface by displaying an X-ray image and displaying a cursor or the like for specifying a position with respect to the X-ray image (for example, a scout image, etc.).

The acquisition unit 74 acquires X-ray image data of various X-ray images generated by the image processing unit 71i. The acquisition unit 74 also acquires a signal indicating the shooting mode transmitted from the control device 50. The following functional elements mainly function when a signal indicating that the automatic shooting mode is set is acquired. Therefore, regarding the following functional elements, the functions or processing contents when the automatic shooting mode is set will be explained.

In the following description, the CT image data stored in the storage unit 72 (or the storage unit 52 of the control device 50) may be referred to as "past CT image data" or "reference CT image data." On the other hand, CT imaging performed after scout imaging of the head B of subject A held in the subject holder 40 is called "current CT imaging", and the CT image data obtained by the CT imaging is "current CT imaging". It is sometimes called "CT image data". "Current CT imaging" is synonymous with the above-mentioned main imaging. Further, although an X-ray image is actually X-ray image data in the internal processing of the control device 50 or the information processing device 70, such X-ray image data can be simply called an "X-ray image." be. When X-ray image data is displayed for human viewing by the display unit 70a, and when expressed from the viewpoint of the observer, the displayed image is referred to as "X-ray image data", which is an abbreviation for "X-ray image data". It is not an "image" but an "X-ray image" in its original meaning.

When there is X-ray image data (CT image data, first region X-ray image data) of a CT image stored in the storage section 72 (or the storage section 52 of the control device 50), the determination image generation section 75 Based on the past CT image data, for example, image data for determination (judgment image data, first X-ray image data). In this case, the ID indicating the subject A linked to the CT image data needs to match the ID of the scout image data. In this embodiment, basically both the first X-ray image data and the second X-ray image data are obtained from the same X-ray imaging apparatus main body 2 or from the same type of X-ray imaging having the same mechanical structure. This is based on X-ray image data obtained by imaging with the device main body 2. This ensures reproducibility of the coordinates. However, a different X-ray imaging apparatus main body 2 may be used as long as the location information can be converted. For example, when a two-directional scout image is acquired by the control device 50, the determination image generation unit 75 refers to the X-ray irradiation angle at which the two scout images were obtained, and generates a corresponding image corresponding to the irradiation angle. Two tomographic images may be generated from the CT images stored in the storage unit 72. The determination image generation unit 75 may generate one or more Raysum images from the CT images stored in the storage unit 72. In that case, the direction of the Raysum processing may be set to be equal or approximately equal to the direction in which the scout image (second X-ray image) is photographed (the direction of irradiation of the X-ray beam). For example, when two-directional scout images are acquired by the control device 50, the determination image generation unit 75 refers to the X-ray irradiation angle at which the two scout images were obtained, and determines the X-ray irradiation angle to be equal to the X-ray irradiation angle. Alternatively, two raysum images may be generated by performing raysum processing in substantially equal directions.

The target range of the Raysum processing does not have to be the entire CT image data. The range to be subjected to the ray sum processing may be a partial area, such as a certain range before and after the central portion, for example. The determination image generation unit 75 may generate a cross-sectional image instead of the Raysum image. For example, the determination image generation unit 75 generates tomographic image data of a cross section perpendicular to the X-ray irradiation direction when the scout image is obtained, and that is a cross section at the center of the X-ray irradiation direction in the CT image data. generate.

As the first X-ray image data, X-ray image data obtained by MIP (Maximum Intensity Projection) may be used. MIP is a method in which a viewpoint direction is determined and a projection process is performed on three-dimensionally constructed X-ray image data such as X-ray CT image data, and the maximum value in the projection path is displayed on a projection plane. In addition, processing is performed to extract, for example, metal parts and characteristic hard tissue parts from the three-dimensional volume rendering image data, and metal parts and characteristic hard tissue parts are also extracted from the second X-ray image data. The determination may be made by processing. Processing may be performed to increase the transparency of the three-dimensional volume rendering image data and project it onto the projection surface. In this way, the image data obtained by two-dimensional processing of the three-dimensional image data is used as the first X-ray image data. Good too. Image processing in which a tissue structure is projected in one direction, such as in Raysum processing or MIP processing, is referred to as projection or projection processing. As the projection processing, MinIP or SSD may be performed depending on the case.

The determination unit 76 performs image recognition on, for example, the scout image data (second X-ray image data) and the CT image data stored in the storage unit 72, that is, the reference CT image data, thereby determining whether A third region corresponding to the imaging region (first region, first portion consisting of part of head B) of the reference CT image data is determined. The determination unit 76 compares the scout image data with the determination image data generated by the determination image generation unit 75 and calculates the degree of coincidence or similarity of these image data by, for example, performing pattern matching. do. The determining unit 76 determines that an area in which a degree of coincidence or similarity of a certain level or higher is obtained with respect to the scout image is a third area corresponding to a photographed area of a past CT image. This third region corresponds to the first portion where past CT images were taken, and is a region of interest in dental diagnosis or dental treatment. The region to be compared does not necessarily have to be the entire region corresponding to the first portion. The region to be compared may be a part of the region corresponding to the first portion, for example, only the central region may be compared.

The coordinate calculation unit 77 calculates the coordinates of the center position of CT imaging based on the third region determined by the determination unit 76. More specifically, the coordinate calculation unit 77 may calculate, for example, the coordinates of the center position of the third region obtained by the determination, and use these coordinates as the center position of CT imaging. The coordinate calculation unit 77 transmits a signal indicating the calculated coordinates to the imaging area setting unit 56 of the control device 50 via the interface 73.

The control unit 78 generates information for overall control of X-ray imaging by the X-ray imaging apparatus 1 when the automatic imaging mode is set, and passes it to the control device 50. The control unit 78 determines the conditions (for example, the coordinates corresponding to the imaging direction and imaging range in scout imaging) under which the first imaging unit 10 takes the scout image (second imaging X-ray image data), and performs operations under the conditions. Control support information is given to the control device 50, and the control device 50 controls the first image capturing section 10 so that the image capturing is performed. Note that when the type of scout photography is not set in the mode setting section 55 of the control device 50, the control section 78 selects two typical irradiation angles (for example, 0 degrees or 180 degrees in front of the chin rest 43). The control device 50 controls the control device 50 to perform two-direction scout photography at a first angle and a second angle shifted 90 degrees clockwise or counterclockwise from the first angle when viewed from above in the central axis L direction. Support information may also be provided. The control unit 78 may directly control the control device 50, or the control unit 78 may directly control the first imaging unit 10.

In this specification, “first region The image data includes frame data (not processed), that is, raw X-ray image data, and processed X-ray image data that is image data obtained by processing the raw X-ray image data. The first region X-ray image data is stored in the storage section 72 (or the storage section 52). That is, the X-ray image data in the first area stored in the storage section 72 (or the storage section 52) may be raw X-ray image data or processed X-ray image data. The "first X-ray image data" used in the comparison process by the determination unit 76 may be the first region X-ray image data without any processing, or the first region X-ray image data may be the first region X-ray image data that has not been processed. It may also be image data. That is, the "first X-ray image data" is based on the first region X-ray image data. For example, "first X-ray image data" includes raw X-ray image data stored in the storage unit 72 (or storage unit 52) and processed X-ray image data stored in the storage unit 72 (or storage unit 52). data, and processed X-ray image data obtained by processing raw X-ray image data during comparison processing. The "first X-ray image data" may also include processed X-ray image data obtained by further processing the processed X-ray image data stored in the storage unit 72 during the comparison process. The "first X-ray image data" based on the first region X-ray image data can be said to be image data derived from the first region X-ray image data, and can also be said to be image data that is composed of the first region X-ray image data. It can also be said that it is image data.

Regarding "second region X-ray image data" obtained by X-ray imaging the second region (second region) and "second X-ray image data" based on the second region X-ray image data. , the same definitions as above apply. "Second region X-ray image data" obtained by X-ray imaging the second region is one-shot imaging data as it is (without any processing) obtained by X-ray imaging such as two-directional scout imaging, i.e. It includes raw X-ray image data and processed X-ray image data that is image data obtained by processing the raw X-ray image data. The "second X-ray image data" based on the second region X-ray image data may be the second region X-ray image data as is, or may be image data obtained by processing the second region X-ray image data. You can. That is, the "second X-ray image data" is based on the second area X-ray image data. "Second X-ray image data" based on the second region X-ray image data can be said to be image data derived from the second region X-ray image data, or is composed of the second region X-ray image data. It can also be said that it is image data.

Processed X-ray image data includes "visualized processed X-ray image data," which is image data that has been processed to a state close to the visualization level, and "visualized processed X-ray image data," which is image data that has been processed to the level of visualization. data”. "Visualized processed X-ray image data" is raw X-ray image data that has been slightly processed for visualization. It cannot be recognized as an image. "Visualized processed X-ray image data" differs from "visualized processed X-ray image data" in whether it can be recognized as an image of the head, upper jaw, lower jaw, or teeth. "Visualized processed X-ray image data" includes, for example, image data such as three-dimensional volume data that has been obtained by back projecting frame image data, but has not undergone tomographic image processing or volume rendering image processing. Can be mentioned. For example, when these terms are used regarding CT imaging, the various image data mentioned above are "raw CT image data," "processed CT image data," "visualized processed CT image data," and "visualized processed CT image data." can be called respectively.

Here, the determination unit 76 of the information processing device 70 is not limited to the above-described determination method, and may perform determination using a determination model learned by machine learning, for example. For example, as shown in FIG. 7, as another embodiment of the present disclosure, an information processing device 70 including a determination model storage section 79, a server 200 for machine learning, and the X-ray imaging apparatus main body 2 are configured. An X-ray imaging system M may be provided.

As shown in FIGS. 7 and 10, the determination unit 76 stores past CT image data CT1 (first region X-ray image data) or determination image data in the determination model 210 stored in the determination model storage unit 79. Input D1, D2 (first X-ray image data) and scout image data (second X-ray image data) such as two-directional scout image data C1, C2, which is X-ray image data of two-directional scout images. do. The determination unit 76 obtains, as the third region, an area that is estimated to correspond to the first part (the part where the past CT image was taken) in the scout image data that is output from the determination model 210.

Note that the number of past CT image data is not limited to one, and there may be cases in which a plurality of pieces of past CT image data are stored. For example, this may be the case when CT images were taken at a plurality of different times in the past and a plurality of CT image data are stored. In this case, a priority order may be determined, such as using the latest data as the determination image data. The operator may be able to select CT image data to be used as the image data for determination. The operator may be able to select CT image data to be used as the image data for determination from a list display of thumbnails or the like.

The server 200 includes a judgment model teacher data generation section 201, a judgment model teacher data storage section 202, and a judgment model learning section 203 as functional elements for generating the judgment model 210 described above. The server 200 is a computer device including a processor (eg, CPU, etc.), memory (eg, ROM, RAM, etc.), and may be, for example, a workstation. The server 200 may be configured by one or more devices provided on a cloud, for example.

The judgment model teacher data generation unit 201 generates teacher data for learning the judgment model 210. The judgment model teacher data storage unit 202 stores the teacher data generated by the judgment model teacher data generator 201. The judgment model learning unit 203 generates a judgment model 210, which is a learned model, by performing machine learning using the teacher data stored in the judgment model teacher data storage unit 202. For example, the determination model is based on the pattern of the first image shown in past CT image data (first region X-ray image data) or determination image data (first X-ray image data) and the X-ray image of the scout image. It consists of a learned model that uses machine learning to determine the identity of a portion of a second image pattern shown in image data (second X-ray image data) that corresponds to a first image pattern. That is, the judgment model 210 is a teacher that includes first information including first X-ray image data and second information including a third region corresponding to a first portion within the second X-ray image data. This is a trained model that has been machine learned using data.

FIG. 10 is a diagram schematically showing an overview of the determination model 210. As shown in FIG. 10, first, the judgment model training data generation unit 201 generates the past judgment results obtained from the subject A and the X-ray image data of the CT image or the judgment image according to the judgment results. A plurality of sets of teacher data including X-ray image data and X-ray image data of scout images are generated. The training data may include, for example, information on the pattern of the first image shown in the X-ray image data (first region X-ray image data) or the determination image data (first X-ray image data) of past CT images. , this first image pattern and information on a portion of the second image pattern shown in the X-ray image data (second X-ray image data) of the scout image that corresponds to the first image pattern. include.

Subsequently, the judgment model learning unit 203 generates a judgment model 210, which is a learned model, by performing machine learning using the teacher data accumulated in the judgment model teacher data storage unit 202. The machine learning method executed by the judgment model learning unit 203 is not limited to a specific method, and various methods such as SVM, neural network, deep learning, etc. can be used, for example. For example, when the judgment model 210 is configured by a neural network, a trained model in which the parameters of the intermediate layer of the neural network are tuned using teacher data is obtained as the judgment model 210.

The determination model 210 obtained by such machine learning is based on past CT image data CT1 (first region X-ray image data) or determination image data D1, D2 (first X-ray image data), and two-direction scouting. Input the X-ray image data (second X-ray image data) of the scout image such as image data C1 and C2 to correspond to the first part (the part where the past CT image was taken) in the scout image. This is a trained model configured to output the estimated region as a third region. The decision model 210 generated by the decision model learning unit 203 is provided from the server 200 to the information processing device 70 and is stored in the decision model storage unit 79 of the information processing device 70 .

The determination unit 76 does not necessarily need to determine the third area using the determination image data D1 and D2 generated by the determination image generation unit 75. The determination unit 76 determines the third area based on the correspondence between the unprocessed past CT image data CT1 (first area X-ray image data) and the two-direction scout image data C1 and C2 (second X-ray image data). may be determined (see FIG. 10). Since the training data used for learning includes the X-ray image data of unprocessed past CT images, the judgment model learning unit 203 uses the unprocessed past CT image data CT1 and the bidirectional scout image data C1, C2. You may learn to determine the third region based on the correspondence. The determination model learning unit 203 determines the correspondence between unprocessed past CT image data CT1 (first area X-ray image data) and two-directional scout image data C1 and C2 (second X-ray image data), and As shown in the image, both the correspondence between the data obtained by processing the past CT image data CT1 (first X-ray image data) and the two-directional scout image data C1 and C2 (second X-ray image data) , may be studied in a mixed manner (in combination or together).

Next, the processing flow executed by the X-ray imaging apparatus 1 (or the X-ray imaging system M) of this embodiment will be described with reference to FIGS. 8 and 9. First, at some point in the past, a first area corresponding to a first part consisting of a part of the head B of a subject A is subjected to CT image data (first area X-ray image data). has been acquired (first acquisition step). The CT image data is stored in the storage section 72 (or the storage section 52). The control unit 78 of the information processing device 70 receives imaging conditions set for the X-ray imaging device 1 (step S01). The photographing conditions here are, for example, the photographing mode set in the mode setting section 55 of the control device 50. For example, the control unit 78 receives a signal indicating that X-ray imaging is to be performed in the automatic imaging mode described above as the imaging condition. "Photographing a first region corresponding to a first portion" is interpreted to mean that the first region targets the first portion. "Photographing a first region corresponding to a first portion" may be interpreted as meaning that the first region is a photographing region in which the first portion is the object of photographing.

In the following explanation, a case will be described in which information indicating that the shooting condition is automatic shooting mode is input. Next, the control unit 78 of the information processing device 70 performs two-direction X-ray imaging of a portion of the head B including the upper and lower jaws (a second portion consisting of at least a portion of the head B) from two different directions. Information for executing scout imaging is sent to the control device 50 of the X-ray imaging apparatus main body 2. Then, the control device 50 controls the first imaging unit 10 to perform two-directional scout imaging (step S02). In step S02, the region to be imaged (second region) is wider than the region to be imaged (first region) in the past CT imaging, and covers at least a portion of the region to be imaged in the past CT imaging. This is the area that includes. The area to be imaged (second area) may be an area that includes the area to be imaged in the past (first area), and the area to be imaged (second area) may be the area to be imaged in the past. The area may be wider than the area (first area). For example, as shown in FIG. 11, the target region R of past CT imaging has a cylindrical shape with a diameter of 40 mm and a height of 40 mm. The target area for scout photography is set to include this cylindrical area R. The second region corresponds to a second portion consisting of at least a portion of the head B. The second region includes at least a portion of the first region. "Photographing a second region corresponding to the second portion" is interpreted as the second region targeting the second portion. "Photographing a second region corresponding to the second portion" may be interpreted as meaning that the second region is a photographing region in which the second portion is the subject of photographing.

Next, the acquisition unit 74 of the information processing device 70 acquires two scout images (projected images) obtained by two-directional scout photography, and displays them on the display unit 70a (step S03; second acquisition step). FIG. 12 is a diagram showing a procedure for creating a scout image as a second X-ray image. FIG. 13 is a diagram showing an example of two scout images. As a result of the two-directional scout imaging, two-directional scout image data C1 (first scout image data C1) and two-directional scout image data C2 (second scout image data C2) are obtained by X-ray irradiation from two different directions, It is displayed on the display section 70a. When performing two-directional scout imaging using simple projection using cone beam irradiation, the X-ray generator 21 and the X-ray detector 31 are rotated around the rotation axis RCT by the rotation drive of the rotation arm 12. The first photographing unit 10 is controlled, and first scout image data C1 is acquired by one-shot photography from a certain direction, and second scout image data C2 is acquired by one-shot photography from another direction. The certain direction and the other direction are preferably two orthogonal directions. The first scout image data C1 and the second scout image data C2 are detected on the detection surface of the X-ray detector 31. Note that in FIG. 12, the display above the cone beam CB is omitted to facilitate understanding.

Next, the determination unit 76 of the information processing device 70 refers to the storage unit 72 or the storage unit 52 and determines whether or not there is CT image data photographed in the past (step S04). The determination unit 76 determines whether CT image data having an ID that matches the ID of the subject A shown in the X-ray image data of the scout image is stored in the storage unit 72 or the storage unit 52. When determining that there is CT image data photographed in the past (step S04; YES), the determination unit 76 performs a target area determination process (step S05). When the determination unit 76 determines that there is no CT image data photographed in the past (step S04; NO), the control unit 78 displays a display so that the imaging area can be manually input via the operation unit 50b and the display unit 50a. The message is displayed on the section 50a. A message may be displayed on the display section 70a to prompt the user to manually input the shooting area via the operation section 70b and the display section 70a. Thereby, the control unit 78 receives the input of the area to be photographed and accepts the position designation (step S10). The control unit 78 transmits a signal indicating the imaging area to the imaging control unit 58 via the interface 73, and the imaging control unit 58 controls the drive control unit 57. The control section 78 may directly control the drive control section 57.

In this way, preferably, the determination unit 76 refers to the storage unit 72 or the storage unit 52 and selects the first area having the ID that matches the ID of the subject A assigned to the second area X-ray image data, for example. Depending on whether the X-ray image data is stored in the storage unit 72 or the storage unit 52, it is determined whether or not the first region X-ray image data obtained by photographing the subject A in the past is held. When the determination unit 76 determines that there is first region X-ray image data photographed in the past, it performs a target region determination process. More preferably, for example, in a case where the first region X-ray image data having an ID that matches the ID of the subject A assigned to the second region X-ray image data is not stored in the storage unit 72 or the storage unit 52, If the determining unit 76 determines that there is no first region X-ray image data of the subject A photographed in the past, a display prompting the operator to manually input the photographing region is displayed on the display unit 70a. In this case, preferably, the control unit 78 receives an operation input for the area to be photographed and receives position designation. In this manner, the determination unit 76 refers to the ID of the subject A given to the X-ray image data and determines the identity of the subject, thereby making it possible to prevent the subject from being confused.

As shown in FIG. 9, in the target region determination process, first, the determination section 76 acquires past CT image data (first region X-ray image data) from the storage section 72 (or the storage section 52). Step S51). Then, the determination image generation unit 75 generates determination image data (first X-ray image data) based on past CT image data (step S52). FIG. 14 is a diagram showing an example of image recognition for the first X-ray image. As shown in FIG. 14, the determination image generation unit 75 refers to the irradiation angle in the two-direction scout imaging in step S02, and generates two pieces of tomographic image data D1 and D2 corresponding to the irradiation angle from the past. Generated from CT image data. For example, the determination image generation unit 75 refers to the irradiation angle in the two-direction scout photography in step S02, and generates a direction that is equal to or approximately equal to the irradiation angle (hereinafter, a direction including both of these directions will be referred to as a direction). Two tomographic image data D1 and D2 are generated by determining a cross section that is perpendicular or substantially perpendicular to the "substantially irradiation direction"). For example, when X-ray image data (second X-ray image data) of a two-directional scout image is acquired by the control device 50, the determination image generation unit 75 determines the irradiation angle in the two-directional scout imaging in step S02. Two Raysum image data may be generated by referring to and performing Raysum processing in a direction (substantially the irradiation direction) that is equal to or approximately the same as the irradiation angle. As image processing, a process of collecting pixel data in a cross section that is substantially orthogonal to the irradiation direction or substantially perpendicular to the irradiation direction and has a thickness in the substantially irradiation direction can also be considered. Examples of collection methods include averaging pixel data aligned approximately in the irradiation direction, integrating methods, generating multi-layered two-dimensional data aligned approximately in the irradiation direction and then synthesizing it, and volume rendering within the tomography. , there are various possibilities.

Assuming that the past CT image data is CT image data PI, projection processing is performed from multiple directions without referring to the information on the irradiation angle when the CT image data PI was obtained. Image data matching the area may be searched for. Since the orientation of the head B held by the subject holder 40 is almost constant, it is efficient to perform the search only by projecting in the y direction (multidirectional in the y direction). That is, the search may be performed using an image in which the three-dimensional CT image data PI is rotated around the z-axis and observed from the y direction.

In addition, in the process of generating the determination image data D1 and D2, correction may be applied to the CT image data in consideration of the magnification rate of scout imaging. Although the scout image data has different magnification factors in the front and back, by adding such correction to the CT image data, the determination accuracy can be improved.

Returning to FIG. 9, the determination unit 76 uses the first scout image data C1 and second scout image data C2 obtained by two-directional scout photography, and the two determination image data D1 and D2 generated in step S52. The degree of coincidence or similarity of these image data is calculated by comparing them and performing pattern matching, for example. The determination unit 76 determines that the region for which a degree of coincidence or similarity of a certain level or higher is obtained is the third region corresponding to the first portion that was the subject of the past CT image (step S53; process).

After the target area determination process in step S53, a process for determining whether the target area determination was successful or failed may be performed. For example, if the determination unit 76 determines that the target area has been successfully determined, it performs the process of the next step S06 (see FIG. 8). As a result of the image comparison process, a region having a degree of coincidence or similarity above a certain level may not be found in the first scout image data C1 and the second scout image data C2 (second X-ray image data). obtain. In such a case, the determination unit 76 determines that determination of the target area has failed. If the determination unit 76 determines that the target area determination has failed, the control unit 78 receives input of the area to be photographed and accepts position designation. This process corresponds to the designated position acceptance process in step S10 described above.

Returning to FIG. 8, the determination unit 76 causes the display unit 70a to display the area determined to be the third area in the first scout image data C1 and the second scout image data C2 as an X-ray image (step S06). . The area determined to be the third area in step S06 is the current CT imaging target area. For example, the determination unit 76 displays a rectangular frame surrounding the target area on the X-ray image of the first scout image data C1 and the X-ray image of the second scout image data C2, and also A point is displayed on the X-ray image of the first scout image data C1 and the X-ray image of the second scout image data C2. FIG. 15 is a diagram showing an example of a third area displayed on two scout images. In many cases, past CT image data was taken with the center of the volume as the center of rotation of the X-ray generator 21 and the X-ray detector 31. Therefore, even after scout imaging, the center points G1 and G2 of the target area are set to become the new turning centers of the X-ray generator 21 and the X-ray detector 31. As shown in FIG. 15, in step S53 and step S06, the frame lines F1, F2 and the center point are placed on the X-ray image of the first scout image data C1 and the X-ray image of the second scout image data C2, respectively. G1 and G2 are shown. When using a two-directional scout image, the determination unit 76 determines the third area such that the positions of these frame lines F1, F2 and center points G1, G2 in the vertical direction match. The vertical position in the X-ray image of the first scout image data C1 and the X-ray image of the second scout image data C2 corresponds to the vertical position (that is, height) in the absolute coordinate system. In addition, in cases such as when the magnification rate in CT photography (X-ray photography of the first region) and the magnification rate in scout photography (X-ray photography of the second region) are different, it is determined that the area is in the third area. The center point of the area may be located outside the biological tissue of the subject A. In such a case, the determination unit 76 adjusts the target area (specifically, the positions of the frame lines F1 and F2) so that at least the positions of the center points G1 and G2 are located on the living tissue of the subject A. You may.

Next, the coordinate calculation unit 77 calculates the coordinates of the center position of the third area (step S07). The coordinate calculation unit 77 calculates, for example, the position information shown in the first scout image data C1 and the second scout image data C2, and the positions of the center points G1 and G2 in the first scout image data C1 and the second scout image data C2. From the information, two straight lines corresponding to the first scout image data C1 and the second scout image data C2 are calculated, and their intersection points are calculated. These two straight lines are, for example, a straight line connecting the focal point 21b when the first scout image data C1 is photographed and the position of the center point G1 shown on the X-ray image of the first scout image data C1; This is a straight line connecting the focal point 21b when the second scout image data C2 is photographed and the position of the center point G2 shown on the X-ray image of the second scout image data C2. The coordinate calculation unit 77 calculates the coordinates of this intersection as the coordinates of the center position of the third area.

Note that the output of the determination unit 76 is position information of the third area on the X-ray image, and the coordinate calculation unit 77 calculates the center position of the third area in the XYZ orthogonal coordinate system based on the position information. You may. The positional information of the third region on the X-ray image may be, for example, information numerically indicating the position of the third region in the two-dimensional matrix of the X-ray image.

Alternatively, the determination unit 76 may be configured to output up to the coordinates. Coordinate information may be added to the learning of the judgment model 210 in the judgment model learning unit 203 in addition to the X-ray image data information. The determination model learning unit 203 may be caused to perform learning so as to output the coordinate information of the third region in response to coordinate information being input to the determination model 210 in addition to information on the X-ray image data. That is, the determination model 210 may have the function of the coordinate calculation section 77.

The second region only needs to include at least a portion of the first region. FIG. 16 is a diagram illustrating an example in which the X-ray image portion of FIG. 15 is omitted and the arrangement and/or size of the outline of the X-ray image is changed. As shown in FIG. 16, the first scout image data C1 and the determination image data D1 overlap in some areas (see the hatched area RC in the figure). If the determining unit 76 can determine coincidence or similarity through image recognition of this overlapping region RC, the position indicated by the center point G1 can be specified, and the position of the third region can be calculated. As in the image data C1 and D1 illustrated in FIG. 16, the second area may be larger than the first area but may include only a part of the first area. That is, the second region may partially overlap the first region.

As in image data C1, D1/C2, D2 illustrated in FIG. 15, the second area may be larger than the first area and may include the entire first area. That is, the second region may include the first region.

Note that the above frame lines F1, F2 and center points G1, G2 are data automatically generated by the X-ray imaging apparatus 1, but in conventional manual positioning based on a scout image, the frame cursor and position specifying cursor It corresponds to what was expressed as.

Next, the control unit 78 sends information regarding the third area (control support information including the above-mentioned center position, including support information such as appropriate tube current, etc.) to the imaging area setting unit 56 of the control device 50 via the interface 73. ). A drive control section 57 of the control device 50 executes drive control of the drive mechanism 7 and the like, and an imaging control section 58 controls the X-ray generation section 20 and the X-ray detection section 30. As a result, the first imaging unit 10 is driven (step S08; control process), and CT imaging is further performed (step S09). In these steps S08 and S09, the control unit 78 gives information to the control device 50, so that the control device 50 controls the drive mechanism 7 to move the X-ray generator 21 and the X-ray detector 31, and 1. The imaging unit 10 is caused to perform CT imaging (X-ray imaging) of the third region. In this CT imaging, the coordinates of the center position of the third area become the center of rotation. That is, the rotating arm 12 (the rotating shaft 12d, the X-ray generator 21, and the X-ray detector 31) is moved so that the central axis L of the rotating shaft 12d passes through the coordinates of the center position of the third region. The coordinates of the center position of the third area are the turning center setting target position, which is a target for setting the turning center, and the information on the coordinates of the center position of the third area is turning center setting target position information. Regarding the execution of X-ray irradiation, it is preferable to permit execution only while the emission switch 93 of the X-ray irradiation operation unit 92 is turned on. With this configuration, the photographing control is performed only while the emission switch 93 is turned on, and when the emission switch 93 is turned off, the photographing control is stopped. The X-ray detection signal obtained in step S09 is generated by the image processing section 71i of the information processing section 71 and displayed on the display section 50a and/or the display section 70a.

The above series of processes (steps S02 to S09) are executed while the fixing condition of the head B of the subject A is maintained. In the series of processing (steps S02 to S09), the subject A keeps the head B held in the subject holder 40, but the processing is performed automatically and no manual work by the operator is required. This saves time and effort. Furthermore, the target area determination processing in step S05 enables accurate positioning for CT imaging.

In this embodiment, the control device 50 performs X-ray imaging control, and the information processing device 70 performs image processing and image recognition determination, but these roles may be changed as appropriate. For example, the control device 50 may be responsible for all or part of image processing and storage. Further, the information processing device 70 may be responsible for all or part of the X-ray imaging control.

In the X-ray imaging apparatus 1 of this embodiment, the head B of the subject A is placed in the central space S, and the X-ray generator 21 irradiates the head B with X-rays. The X-ray detector 31 detects the X-rays that have passed through the head B, thereby obtaining X-ray image data. The storage units 52 and 72 store CT image data (first region X-ray image data) obtained by X-ray photographing a first region corresponding to a first portion that is a part of the inside of the head B. can. When the storage units 52 and 72 store CT image data (first region X-ray image data), the determination unit 76 stores determination image data (first region X-ray image data) based on the CT image data (first region X-ray image data). (first X-ray image data) and one or more scout image data (second region X-ray image data and second X-ray image data) obtained by X-ray imaging the second region. On the other hand, image recognition processing is performed to determine a third region corresponding to the first portion. Then, the control unit 78 provides control support information to the control device 50, and the control device 50 controls the drive mechanism 7 to cause the X-ray generator 21 and the X-ray detector 31 to take an X-ray image of the third region. Therefore, with the subject A held in the subject holder 40, the second part of the head B of the subject A is photographed to obtain scout image data (second region X-ray image data), and then the head A third region corresponding to the first portion within the organ can be automatically X-rayed. Therefore, positioning work by the operator or the like with respect to the scout image data (second region X-ray image data or second X-ray image data) is no longer necessary. Even if the posture of subject A has changed between the judgment image data (first X-ray image data) derived from the past image and the scout image data (second X-ray image data) derived from the current image. , since the third region is determined based on image recognition, positional accuracy is improved. According to the X-ray imaging apparatus 1, positioning for X-ray imaging can be performed simply and accurately. "Photographing the third area corresponding to the first part" is interpreted as the third area targets the first part. "Photographing a third region corresponding to the first portion" may be interpreted as meaning that the third region is a photographing region that targets the first portion. The data obtained by photographing the third region (third region) may be referred to as third region X-ray image data, and the data based on the third region X-ray image data may also be referred to as third region X-ray image data. good. The X-ray photography of the first area is referred to as the first X-ray photography, the X-ray photography of the second area is referred to as the second X-ray photography, and the X-ray photography of the third area is referred to as the third X-ray photography. Good too.

A third region is determined from one or more pieces of scout image data using CT image data (three-dimensional image data) having three-dimensional volume data. Therefore, it is possible to more accurately position the third region for X-ray imaging.

Since the three-dimensional position in space is determined using two scout image data (projected image data) obtained by taking X-rays from two directions, it is possible to more accurately take X-rays in the third area. can be positioned.

The determination unit 76 performs image recognition on the CT image data (first X-ray image data) by referring to the X-ray irradiation angles when the two scout image data (projection image data) are obtained. Therefore, the determination unit 76 uses the determination image data D1 and D2, which makes it easy to detect a matching point with a specific portion of the scout image data (second X-ray image data), as the CT image data (first X-ray image data). image data). The third region determination process (ie automatic positioning) can be performed quickly.

The Raysum image data may include information in a predetermined direction (thickness direction) in the CT image data (first X-ray image data). Therefore, by using the Raysum image data for comparison, the accuracy of image recognition can be improved. The determination unit 76 can more accurately detect a matching point with a specific portion of the scout image data (second X-ray image data).

When the determination unit 76 uses the determination model 210 (see FIG. 10), which is a learned model subjected to machine learning, CT image data (first X-ray image data) and scout image data (second X-ray image data) are used. By using the determination model 210 that has learned the correspondence relationship (for example, identity) with the data), the determination accuracy can be improved. That is, the teacher data includes information in which scout image data and CT image data positioned with respect to the scout image data are accumulated. For example, even if the scout image data (second X-ray image data), which is projection image data, includes both right and left tooth information, CT image data (first By using the determination model 210 learned using the data of one of the left and right local images as data), it is possible to easily and accurately position the third region for X-ray imaging. For example, if X-rays are irradiated from the side of the head B in one of the two-directional scout images, both the right and left sides of the tooth row will overlap in this scout image. obtain. Even in that case, a large amount of scout image data with different overlaps between the right and left sides of the dentition is learned so that accurate judgment can be made using CT image data from either the left or right side of the dentition as the first X-ray image data. At the same time, the third region can be accurately positioned for X-ray imaging.

When generating image data for determination, the number of second X-ray image data and the number of image data for determination are equal. In the above embodiment, two determination image data are used for the two second X-ray image data (see FIGS. 15 and 16). That is, when determining the target region (third region), the determination unit 76 uses determination image data (or unprocessed X-ray image data) in a number equal to the number of second X-ray image data. , X-ray image data may be compared. By making the number of X-ray image data used for comparison equal, the determination process is facilitated.

Although the embodiments of the present invention have been described above, the present invention is not limited to the above embodiments. For example, in step S06, the control unit 78 may ask the operator via the display unit 70a whether to approve or reject the displayed position. In the case of approval, the operator performs the approval operation, and in the case of refusal, the operator performs the rejection operation. When a rejection operation is performed, the determining unit 76 may determine and present the next candidate position, or may accept position designation by manual operation.

The determination image data for detecting matching points with respect to the second image data may be generated in any manner based on the first image data. Image data for determination may be generated regardless of the direction of the second image data such as panoramic scout image data. For example, generation of determination image data based on the first image data and determination may be repeated multiple times until a predetermined level of coincidence (or similarity) is detected. That is, sufficient image data for determination to determine the third region may be obtained by trial and error. If the determination of the third region is not successful after repeating the generation and determination of the determination image data a predetermined number of times, or if the determination of the third region is not successful even after a predetermined period of time has elapsed, step S10 Manual reception of the specified position may also be performed.

A second area including at least a part of a previously imaged area may be subjected to panoramic scout photography, and the panoramic scout image data may be used as the second X-ray image data. For example, using panoramic scout image data and a standard XY curve of a dental arch, an X-ray image is reconstructed by plane-projecting the data of the plane corresponding to the panoramic tomographic plane in the first X-ray image data. For example, image recognition and comparison with the first X-ray image data is possible. As long as a part of the dentition is CT-photographed, if the panoramic image is a full-mouth panoramic image, at least a portion of the first X-ray image data applies to any region thereof. By slicing CT image data along a panoramic tomographic plane or by performing Raysum processing, matching or similar locations can be found. Alternatively, a second area that is wider than and includes a previously imaged area may be cephalometrically imaged, and the cephalometric image data may be used as the second X-ray image data. In actual dental treatment, panoramic photography is often performed first at the first consultation. Therefore, when CT image data is saved as the first X-ray image data, panoramic image data is often already saved. In this case, the stored panoramic image data can be recalled and used as second X-ray image data.

CT imaging may be performed as the X-ray imaging of the second region, and the X-ray image data of the CT image may be used as the scout image data (second X-ray image data). In this case, it is preferable to perform CT imaging as X-ray imaging of the second region at a low X-ray dose and reduce noise by binning the light-receiving pixels or the like. A CT tomographic image is displayed by slicing the generated volume data at an arbitrary cross section, and positioning (scouting) can be performed by specifying a position on this tomographic image. If the first X-ray image data is also CT image data obtained in the past, set the tomographic plane of the first image data based on the angle and/or position of the cross section at the time of positioning (scouting). is possible. In addition, for example, if X-ray image data of a CT image of a local area has already been saved and CT imaging of a wide area of the head is separately performed to observe the wide area, the CT image data of the local area may be CT image data of a wide area is obtained. Here, there are cases where it is desired to perform CT imaging of the same location as the CT image data of the local region with higher definition. In this case, it is conceivable to use the CT image data of a local area as the first X-ray image data and the CT image data of a wide area as the second X-ray image data. Of the CT image data input to the determination model 210, both the first X-ray image data and the second X-ray image data may be three-dimensional volume data. In this case, a process is performed to find the location of the three-dimensional volume data of the first X-ray image data in the three-dimensional volume data of the second X-ray image data. It is not necessarily necessary to assume a wide-narrow relationship. It is sufficient that the second region related to the second X-ray image data includes at least a part of the first region related to the first X-ray image data. The second region may be smaller than the first region.

The first X-ray image data taken in the past is not limited to CT image data. For example, tomosynthesis image data or the like may be used as the first X-ray image data.

Here, tomosynthesis image data will be explained. Tomosynthesis image data is image data obtained by tomosynthesis imaging. FIG. 17 is a conceptual diagram for explaining tomosynthesis imaging viewed from the Z-axis direction. In tomosynthesis imaging, as shown in FIG. 17, the rotating arm 12 is rotated from the imaging start position shown by the solid line, through the intermediate position shown by the dotted line, to the imaging end position shown by the two-dot chain line, and the observation target in the subject A is rotated. An X-ray cone beam CB is irradiated onto the target layer TL. Then, the X-ray generator 21 and the X-ray detector 31 are rotated so that the swing angle SWA of the irradiation center axis (X-ray axis CTB) of the X-ray cone beam CB around the rotation axis RCT is 30 degrees or more and less than 180 degrees. X-ray projection images are collected at a predetermined frame rate by irradiating the subject A with the X-ray cone beam CB. The swing angle SWA is also the swing angle of the swing arm 12. In the illustrated embodiment, the pivot axis RCT is centered in the target layer TL.

In tomosynthesis imaging, the direction corresponding to the line of sight direction for observing the generated tomosynthesis image is determined as the swing angle center direction. In the example shown in FIG. 17, the swing angle center direction CTD passing through the center of the swing angle SWA is set at an intermediate position shown by a dotted line. If the swing angle from the shooting start position to the intermediate position is the swing angle HA1, and the swing angle from the intermediate position to the shooting end position is the swing angle HA2, both swing angles HA1 and HA2 are angles that bisect the swing angle SWA. be. The swing angle center direction CTD coincides with the axial direction of the X-ray axis CTB at the intermediate position.

Image data obtained by X-ray photographing the first portion from a plurality of directions can be used as the first X-ray image data. The plurality of directions may be multidirectional. Examples of image data obtained by taking X-rays from multiple directions include tomosynthesis image data and CT image data. The CT image data may be obtained by X-ray photographing the first portion from multiple directions. The tomosynthesis image data may be obtained by X-ray photographing the first portion from several directions, or may be obtained by X-ray photographing the first portion from multiple directions.

Scout image data such as a two-directional scout image may be used as the first X-ray image data. In the scout image data in this case, the frame lines F1 and F2 or their positional information are stored in pairs as regions of interest, as in the two-directional scout image data C1 and C2 shown in FIG. 15. If the new two-directional scout imaging is performed from the same direction as the direction in which the stored two-directional scout image data was acquired, the determination unit 76 recognizes the X-ray image data within the frame lines F1 and F2, A process is performed to find out where in the X-ray image data (second X-ray image data) of the two-directional scout image obtained by the new two-directional scout image, there is a matching or similar point.

The determination unit 76 may calculate a change in the position or orientation of the first portion of the head B based on the first region and the third region. As a result, changes (deviation, etc.) with respect to past shooting times are calculated. Therefore, the change can be presented, and the X-ray image of the third region (third X-ray image) can be corrected based on the change.

The determination unit 76 may calculate a change in the position or orientation of the first portion of the head B based on the first X-ray image data and the second X-ray image data. For example, assume that the first region X-ray image data is image data obtained by CT imaging, and is attached with coordinate information or azimuth information. It is assumed that this first region X-ray image data has been processed and once displayed as X-ray image data on the display unit 50a as a tomographic image sliced at a specific tomographic plane and stored in the storage unit 52. Furthermore, when obtaining second X-ray image data using image data obtained by two-direction scout photography, assume that subject A is positioned facing in a different direction from when acquiring first area X-ray image data. By determining the position of the first region in the second X-ray image data, the determination unit 76 can detect a change in the orientation of the first portion by referring to coordinate information or azimuth information. Then, the X-ray imaging apparatus 1 performs CT imaging of the third region to generate an X-ray CT image of the third region. When displaying this generated X-ray CT image on the display section 50a, it can be displayed by default as an image sliced at the same position as the tomographic image stored in the storage section 52. That is, based on the first X-ray image data and the second X-ray image data, a change in the orientation of the first part of the head is calculated, and an X-ray image obtained by X-ray imaging of the third region is calculated. When processing the data and displaying it on the display unit 50a as an X-ray image, the X-ray image can be generated based on the calculated change in orientation.

The determination unit 76 can also calculate a change in the position or orientation of the first portion of the head B based on the first X-ray image data and the second X-ray image data, and use it for another purpose. . For example, it is assumed that the first region X-ray image data is image data obtained by tomosynthesis imaging, and coordinate information or orientation information is attached. It is assumed that this first area X-ray image data is stored in the storage unit 52. Furthermore, when obtaining the second X-ray image data using the image data obtained by the two-direction scout imaging, assume that the subject A is positioned facing in a different direction from when the first area X-ray image data was obtained. . The determination unit 76 can detect a change in the orientation of the first portion by determining the position of the first region in the second X-ray image data by referring to coordinate information or azimuth information. When the X-ray imaging apparatus 1 performs tomosynthesis imaging of the third region on this basis, drive control of the horizontal movement drive unit 18 and the rotation drive unit 19 is performed so that the target layer in the same direction is imaged during the tomosynthesis imaging. It can be performed. In this way, the movement trajectory of the X-ray generator 21 and the X-ray detector 31 can be set. That is, based on the first X-ray image data and the second X-ray image data, a change in the orientation of the first part of the head is calculated, and the X-ray generator 21 in X-ray imaging of the third region is calculated. and the trajectory of movement of the X-ray detector 31 can be set.

If both the first X-ray photography and the second X-ray photography are performed using rotation of the X-ray generator 21 and the X-ray detector 31, the first X-ray photography and the second X-ray photography By setting the axial directions of the rotation axes RCT during imaging in parallel directions (including the case where they are set at the same location), it may be possible to reduce the burden of determining the third region.

When both the first X-ray photography and the third X-ray photography are performed using rotation of the X-ray generator 21 and the X-ray detector 31 (the first X-ray photography and the second X-ray photography The first X-ray photograph and By setting the axial direction of the rotation axis RCT in the third X-ray imaging in a parallel direction (including when setting it at the same location), it may be possible to reduce the burden of setting the imaging of the third region. . Note that if the same area is photographed in the same manner as the first photograph, it may be considered to reduce the burden of reproduction.

When both the second X-ray photography and the third X-ray photography are performed using rotation of the X-ray generator 21 and the X-ray detector 31 (the first X-ray photography and the second X-ray photography The second X-ray photograph may be performed by setting the rotation axes RCT in parallel directions using the rotation of the X-ray generator 21 and the X-ray detector 31. By setting the axial direction of the rotation axis RCT in the third X-ray imaging in a parallel direction (including when setting it at the same location), it may be possible to reduce the burden of setting the imaging of the third region. .

In the X-ray imaging apparatus 1, the second imaging unit 100 that performs cephalometric imaging may be omitted.

DESCRIPTION OF SYMBOLS 1...X-ray imaging device, 2...X-ray imaging device main body, 7...Drive mechanism, 10...First imaging section, 11...Upper frame (supporting part), 12...Swivel arm (supporting part), 13...Upper frame lifting/lowering Drive unit, 18... Horizontal movement drive unit, 19... Turning drive unit, 20... X-ray generation unit, 21... X-ray generator, 30... X-ray detection unit, 31... X-ray detector, 40... Subject holder, 50 ...control device, 50a...display section, 52...storage section, 70...information processing device, 71...information processing section, 72...storage section, 76...judgment section, 78...control section, 200...server, 210...judgment model, A...Subject, B...Head, S...Central space.

Claims (11)

An X-ray imaging device that takes an X-ray image of a subject's head,
an X-ray generator that irradiates the head with X-rays;
an X-ray detector that detects the X-rays that have passed through the head;
a support part that supports the X-ray generator and the X-ray detector such that a central space in which the head is placed is located between the X-ray generator and the X-ray detector;
a subject holder that holds the subject so that the head is located in the central space;
The X-ray generator and the X-ray detector are driven by driving the support section so that the X-ray generator and the X-ray detector rotate around the central space and X-ray photograph a predetermined area within the central space. and a drive mechanism configured to move the X-ray detector;
a storage unit capable of storing first region X-ray image data obtained by X-ray photographing a first region corresponding to a first portion that is a part of the inside of the head;
second region X-ray image data obtained by X-ray photographing a second region that corresponds to a second region consisting of at least a part of the inside of the head and includes at least a part of the first region; By performing image recognition processing on the second X-ray image data based on the X-ray image data obtained from the storage unit and the first X-ray image data based on the first region X-ray image data acquired from the storage unit, a determination unit that determines a third region corresponding to the first portion;
a control unit that controls the drive mechanism to move the X-ray generator and the X-ray detector to take an X-ray image of the third area after the third area is determined by the determination unit; An X-ray imaging device comprising: The first X-ray image data is three-dimensional image data obtained by CT imaging the first portion or tomosynthesis image data obtained by tomosynthesis imaging the first portion,
The X-ray imaging apparatus according to claim 1, wherein the second X-ray image data is one or more projection image data obtained by X-ray imaging the second portion. 3. The X-ray imaging apparatus according to claim 1, wherein the second X-ray image data is two projection image data obtained by X-ray photographing the second portion from two different directions. The X-ray according to claim 3, wherein the determination unit performs image recognition processing on the first X-ray image data by referring to the irradiation angle of the X-ray when the two projection image data are obtained. Photography equipment. The determination unit compares the first X-ray image data and the second X-ray image data by using image data obtained by two-dimensionally processing three-dimensional image data as the first X-ray image data. , the X-ray imaging apparatus according to any one of claims 1 to 4, wherein the third region is determined. Any one of claims 1 to 5, wherein the determination unit determines the third region by comparing Raysum image data of the first X-ray image data and the second X-ray image data. The X-ray imaging device according to item (1). Any one of claims 1 to 6, wherein the determination unit calculates a change in position or orientation of the first portion of the head based on the first region and the third region. The X-ray imaging device described in . The determination unit inputs the first X-ray image data and the second X-ray image data into a determination model generated by machine learning, and the determination unit inputs the first X-ray image data and the second X-ray image data into a determination model that is output from the determination model. determining a region estimated to correspond to the first portion in to be the third region;
The determination model includes first information including the first X-ray image data and second information including the third region corresponding to the first portion within the second X-ray image data. The X-ray imaging apparatus according to any one of claims 1 to 7, wherein the X-ray imaging apparatus is a trained model that has been machine-learned using training data that includes the X-ray imaging apparatus. further comprising a display unit, the determination unit calculating a change in orientation of the first portion of the head based on the first X-ray image data and the second X-ray image data, When processing the X-ray image data obtained by X-ray imaging of the third region and displaying it on the display unit as an X-ray image, the X-ray image is generated based on the calculated change in orientation. The X-ray imaging device according to any one of Items 1 to 8. The determination unit calculates a change in orientation of the first portion of the head based on the first X-ray image data and the second X-ray image data, and calculates a change in the orientation of the first portion of the head. The X-ray imaging apparatus according to any one of claims 1 to 8, wherein a trajectory of movement of the X-ray generator and the X-ray detector during X-ray imaging is set. An X-ray imaging device that takes an X-ray image of the head of a subject, comprising: an X-ray generator that irradiates the head with X-rays; an X-ray detector that detects the X-rays that have passed through the head; a support part that supports the X-ray generator and the X-ray detector so that a central space in which the head is placed is located between the X-ray generator and the X-ray detector; An X-ray photography method using a radiography device, the method comprising:
a first acquisition step of acquiring first region X-ray image data by X-raying a first region corresponding to a first portion that is a part of the inside of the head;
The subject is held such that the head is located in the central space, and a second region that corresponds to a second portion consisting of at least a part of the inside of the head and that includes at least a portion of the first region a second acquisition step of acquiring second region X-ray image data by X-ray photographing the region;
Image recognition processing is performed on second X-ray image data based on the second area X-ray image data and first X-ray image data based on the first area X-ray image data acquired in the first acquisition step. a processing step of determining a third region corresponding to the first portion within the second region by performing;
After the third region is determined in the processing step, a control step of driving the support section to move the X-ray generator and the X-ray detector to take an X-ray image of the third region; An X-ray imaging method including .

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