JP5352224B2 - X-ray imaging apparatus and panorama image processing program - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a technology for reconstructing a tomographic image in a tomographic position of a subject desired by a user. <P>SOLUTION: A camera-photographed image of an impression taken from the subject that is a radiographic object by a radiographic apparatus is acquired as first prior operation S1-S4. A panoramic image of the subject is acquired as second prior operation S5-S7. Selecting operation for forming an ROI (region of interest) image and a navigation display is performed as main operation S8-S11. In the radiographic apparatus 1, a panoramic image processing means 7 superimposes an orbit of the tomographic position of the subject viewed from a rotation axis direction of a turning driving means 4, on the camera-photographed image and outputs it to a first output means 10, receives instructions for selection and deformation of the displayed orbit of the tomographic position, determines the superimposed width of a plurality of frame images based on information on the selected and deformed orbit, and reconstructs the tomographic image of the selected and deformed orbit to form a panoramic tomographic image. <P>COPYRIGHT: (C)2010,JPO&amp;INPIT

Description

  The present invention relates to an X-ray imaging apparatus and a panoramic image processing program, and in particular, by superimposing a plurality of frame images stored by panoramic imaging of a general medical or dental subject, an arbitrary tomographic image of the subject is captured. The present invention relates to an X-ray imaging apparatus for reconstructing an image and a panorama image processing program.

  Conventionally, a panoramic imaging apparatus is known as a dental X-ray tomography apparatus (see, for example, Patent Document 1 and Patent Document 2). The devices disclosed in Patent Documents 1 and 2 acquire a tomographic image in the vertical plane direction (Z direction) of a dentition at a position of a dentition aligned on a horizontal plane (XY plane), and form one dentition. On the other hand, a plurality of tomographic images (multi-tomographic images) can be displayed.

  The techniques disclosed in Patent Literature 1 and Patent Literature 2 perform a series of imaging corresponding to one tomography of the subject while turning the X-ray source and the X-ray imaging means around the subject. A panoramic image of an arbitrary tomographic image is formed by acquiring a plurality of frame images (frame data), and performing image processing that adds each frame image read from the storage means while shifting the image by a predetermined distance. To do.

Among these, in the panoramic image photographing device disclosed in Patent Document 1, a local region of interest (ROI: ROI) that the user most wants to focus on is observed on the panoramic image while the user observes the panoramic image. Region of Interest). In this panoramic image photographing apparatus, a mouthpiece is detachably attached to a chin rest. When the mouthpiece is picked up by the subject during panoramic photography, the chin rest and the mouthpiece serve to fix the oral cavity of the subject. In this regard, conventionally, techniques related to dentition positioning have been known in dental X-ray tomography apparatuses (see Patent Document 3 and Patent Document 4).
JP 2007-136163 A JP 2006-180944 A Japanese Patent Publication No.7-114773 JP 10-314165 A

  However, in the technique described in Patent Document 1, in response to user operation information, the position specified in the region of interest is the front side or the back side from the cross section having the size of the region of interest on the panoramic image of the standard plane. When examining a cross section with a shift, the shifted position is defined in the structure of the phantom used for the preliminary measurement. For this reason, it is impossible to freely specify the tomographic position of the dentition desired by the user or to view the designated tomographic position freely. Therefore, image reconstruction cannot be performed at a tomographic position of a freely specified dentition. In addition, if the user is a doctor, the reproducibility of the dentition position as the subject is important clinically.

  Therefore, an object of the present invention is to solve the above-described problems and provide a technique that can reconstruct a tomographic image at a tomographic position of a subject desired by a user.

  In order to solve the above problem, an X-ray imaging apparatus according to claim 1 is an X-ray source that irradiates an object positioned at a reference position for X-ray imaging with an X-ray source, and an X-ray transmitted through the object. An X-ray imaging means for receiving light; and a turning drive means for rotating an arm that holds the X-ray source and the X-ray imaging means at a predetermined interval so that the subject can be held around a predetermined rotation center; Frame storage means for storing a plurality of frame images as X-ray imaging results of the subject at standard tomographic positions predetermined in the apparatus corresponding to the positioning of the subject to the reference position, and a specified tomographic position An X-ray imaging apparatus having a panoramic image processing means for generating a panoramic tomographic image and a display means for displaying the panoramic tomographic image, and is attached to a positioning aid for copying a subject type A camera for storing a camera-captured image obtained by aligning the impression of the subject collected by the impression material taken with a standard imaging trajectory indicating the standard tomographic position viewed from the direction of the rotation axis of the turning drive unit A panoramic image processing unit that superimposes the trajectory of the tomographic position of the subject viewed from the direction of the rotation axis of the turning drive unit on the camera captured image and outputs the superimposed image to the display unit; An instruction for selection and deformation with respect to the trajectory of the selected tomographic position is received, an overlapping width of the plurality of frame images is obtained based on the information of the selected and deformed trajectory, and the tomographic image of the selected and deformed trajectory is reproduced. The panoramic tomographic image is generated by configuring.

  According to such a configuration, the X-ray imaging apparatus stores in the camera-captured image storage means the camera-captured image captured after aligning the impression of the subject with the standard imaging trajectory, and X-rays the subject at the standard tomographic position. The result is stored in the frame storage means. Then, the X-ray imaging apparatus superimposes the trajectory of the tomographic position of the subject on the camera photographed image of the subject by the panoramic image processing means and outputs it to the display means. Here, for example, a standard photographing trajectory unique to the apparatus can be adopted as the tomographic position of the subject. This standard imaging trajectory is statistically obtained from the basic tomograms of many subjects, and is different from the basic tomograms of individual subjects to be actually X-rayed. Since the X-ray imaging apparatus of the present invention superimposes the tomographic position trajectory of the subject by, for example, drawing it on the camera-captured image of the impression of the subject, only the trajectory of the tomographic position of the subject is displayed. Compared with the prior art which selects only depending on the above, it is possible to easily select a desired tomographic position in an individual subject.

  In the X-ray imaging apparatus of the present invention, the panoramic image processing means accepts an instruction for selection and deformation with respect to the trajectory of the displayed tomographic position. Here, an instruction for selection and transformation can be received from an input operation on the display screen by using, for example, a GUI. Then, the X-ray imaging apparatus obtains the overlapping width of the plurality of frame images based on the selected and deformed trajectory information by the panoramic image processing means, and reconstructs the tomographic image at the tomographic position to obtain the panorama. A tomographic image is generated.

  The X-ray imaging apparatus according to claim 2 is the X-ray imaging apparatus according to claim 1, wherein the subject is selected and the position of the deformed trajectory based on the information of the selected and deformed trajectory. And an image assumed when there is no deviation by enlarging or reducing the tomographic image reconstructed at the position of the selected and deformed trajectory in accordance with the deviation from the standard tomographic position. Image size correcting means for correcting to an image size corresponding to the size is provided, and the display means displays the tomographic image with the image size corrected as the panoramic tomographic image.

  According to such a configuration, the X-ray imaging apparatus enlarges or reduces the reconstructed tomographic image by the image size correcting unit, and displays a preset display corresponding to the standard imaging trajectory before being selected and deformed. A tomographic image reconstructed at a position shifted from the standard tomographic position can be displayed with the same size as the image size. Therefore, it is possible to easily compare an image of a desired tomographic position on an individual subject with a tomographic image of another desired tomographic position or a tomographic image of another subject.

  The X-ray imaging apparatus according to claim 3 is the X-ray imaging apparatus according to claim 1 or 2, wherein the camera is aligned with the reference position for the X-ray imaging and the standard imaging trajectory. Is provided in the arm.

  According to such a configuration, the X-ray imaging apparatus includes the camera that captures the impression of the subject in a state in which the camera is aligned with the reference position for X-ray imaging and the standard imaging trajectory. Therefore, it is possible to easily acquire and save a camera-captured image of the impression of the subject. In addition, it is not necessary to separately prepare an alignment device or the like for acquiring a camera-captured image of the subject impression.

  The panorama image processing program according to claim 4 is obtained by panoramic imaging of a tomographic image of a subject by an X-ray imaging apparatus in order to generate a panoramic tomographic image of a specified tomographic position of the subject. A standard image of the X-ray imaging apparatus for an impression of the subject collected by a frame image storage means for storing the plurality of frame images and an impression material attached to a positioning aid for copying the type of the subject A computer having camera-captured image storage means for storing a camera-captured image captured by a camera in alignment with a trajectory, drawing means for drawing a trajectory of the tomographic position of the subject, and the tomographic position of the drawn subject Combining means for combining the trajectory and the camera-captured image and outputting it to the display means, selection for the trajectory of the displayed tomographic position and instructions for deformation A change receiving unit that receives and draws the selected and transformed trajectory to the drawing unit; obtains an overlapping width of the plurality of frame images based on the information of the selected and transformed trajectory; and the selection and transformation It is made to function as an image reconstruction means for reconstructing a tomographic image of the trajectory formed. By being configured in this way, a computer in which this program is installed can realize each function based on this program.

  According to the present invention, the X-ray imaging apparatus superimposes and displays the trajectory of the tomographic position of the subject on the camera-captured image of the subject's impression, and selects and deforms the tomographic position of the displayed tomographic position. The designation can be accepted and a tomographic image at the tomographic position can be reconstructed. Therefore, the tomographic image can be reconstructed at the tomographic position of the subject desired by the user. As a result, it is possible to generate an image that is easy to use for the user viewing the display.

  Hereinafter, the best mode for carrying out the X-ray imaging apparatus of the present invention (hereinafter referred to as “embodiment”) will be described in detail with reference to the drawings.

[Overall configuration of X-ray imaging apparatus]
FIG. 1 is a configuration diagram schematically showing an X-ray imaging apparatus according to an embodiment of the present invention. The X-ray imaging apparatus 1 captures an X-ray image of a predetermined tomography along a dentition in the maxilla / mandible of a subject (person) by panoramic radiography (panoramic X-ray tomography) to obtain a dental tomographic image. Is to be generated. As shown in FIG. 1, the X-ray imaging apparatus 1 includes an X-ray source 2, an X-ray imaging means 3, a turning drive means 4, an A / D conversion means 5, an image storage means 6, and a panorama. Image processing means 7, processed image storage means 8, all image display storage means 9, first output means 10, camera 11, auxiliary tool (positioning auxiliary tool) 12, image storage means 13, and camera Image processing means 14, processed image storage means 15, all image display storage means 16, second output means 17, first input means 18, and second input means 19 are provided.

[Outline of X-ray system]
<Panorama tomographic image>
A panoramic tomographic image generated and displayed by the X-ray imaging apparatus 1 (hereinafter also simply referred to as a tomographic image) will be described with reference to FIG. FIG. 2 is an explanatory diagram showing a plurality of slices assigned to correspond to a dentition as a subject. In the state shown in FIG. 2, the X-ray source 2 emits X-rays from the molar part d side of the dentition of the person who is the subject, and the X-ray imaging means 3 receives light on the front tooth part c side of the dentition. However, during imaging, the X-ray source 2 and the X-ray imaging means 3 rotate and the position of the rotation center O slides. In FIG. 2, the basic fault b ₀ is taken at the center in the depth direction before and after the dentition, the lingual fault b _m on the rear side (inner side) of the dentition in the depth direction, and the buccal fault b _n on the front side (outer side). Illustrated. Here, m is identification information (m = −1, −2, −3,...) Of the tongue side direction, and n is identification information (n = 1, 2, 3,...) Of the buccal direction. Each is shown. However, in FIG. 2, one each of the lingual-side fault and the buccal-side fault is illustrated. Since the tomography is farther from the rotation center O toward the cheek side, the lateral width of the panoramic tomographic image becomes longer accordingly. When the subject is a dentition of a human body, the basic tomography b ₀ is a distance from the rotation center O to the first central incisor on the front tooth c side, for example, about 50 mm, lingual direction tomography, cheek side The directional fault is preferably set in a region from the basic fault b ₀ to about ± 30 mm, for example.

<Region of Interest (ROI)>
A region of interest (ROI) as operation input information received by the first input unit 18 by the X-ray imaging apparatus 1 will be described. FIG. 3 is a diagram illustrating an example of an input region of interest (ROI), where (a) corresponds to the ROI specified on the panoramic tomographic image displayed on the screen, and (b) corresponds to the specified ROI. Each fault in the depth direction is shown. A region of interest (ROI) 301 is designated as a region where a user wants to obtain a tomographic image (region to be displayed), and is reconstructed with respect to a basic tomography as indicated by a broken line in FIG. For example, it is indicated by a rectangular area on the panoramic tomographic image. The range of the region of interest is specified by a two-dimensional coordinate value. When the user selects the region of interest 301 by, for example, a mouse click-and-drag operation, the panoramic image processing means 7 detects the coordinate value of the selected region.

  Selecting this region of interest (ROI) 301 designates the fan-shaped range of FIG. 3B in the dentition. That is, the left boundary line 302 and the right boundary line 303 of the region of interest 301 in FIG. 3A are represented by points on the basic fault in FIG. 3B. And the designation of the left boundary line 302 and the right boundary line 303 represented by the points on the basic fault in FIG. 3B means that the straight lines 304 and 305 are designated in FIG. 3B. . Although it is possible to designate the entire panoramic tomographic image as the region of interest (ROI) 301, in the following, when the region of interest is designated, the region of interest is set in a part of the panoramic tomographic image, and the region of interest is designated. When there is no area of interest, a region of interest is set for the entire panoramic tomographic image.

FIG. 4 is an explanatory diagram showing processing in which the panoramic image processing means of the X-ray imaging apparatus according to the embodiment of the present invention extracts a frame image from the ROI. Here, the panoramic tomographic image at the position of the standard imaging trajectory is denoted as B ₀ . As shown in FIG. 4, the two-dimensional coordinate values of the upper left point of the rectangular region of interest on the panoramic tomographic image B ₀ and the lower right point that is the diagonal thereof are (x, y) and (x ₁ , y _{1, respectively.} when it is detected as a), panorama image processing unit 7, a panoramic tomographic image B of all the frame images g constituting the entire _0, point horizontal coordinate x in the panoramic tomographic image B ₀ To the right in the figure, a plurality of frame images g constituting a portion of the region of width (x ₁ -x) are specified as frame images g to be extracted.

  When the user selects the region of interest 301 in FIG. 3A, it should be used for reconstruction processing among all the frame images g photographed at the position of the basic tomogram (position of the standard photographing trajectory) as shown in FIG. A plurality of frame images g are designated. However, when the user desires to display a tomographic image at a fault position other than the basic fault, the selection of the region of interest 301 is not sufficient.

  Here, tentatively, a plan view of the dentition including the position of the basic fault as shown in FIG. 3B is presented to the user by a screen display, and the fault position one inner side from the basic fault, for example, from the user. It is conceivable to receive information that specifies etc. However, the plan view of the dentition shown in FIG. 3B corresponds to the position of the basic tomography and the position of the standard imaging trajectory determined in advance by the apparatus of the X-ray imaging apparatus 1 as a standard. is there. That is, the position of the basic fault in the plan view of the dentition shown in FIG. 3B corresponds to the theoretical dentition position that is statistically determined with the cooperation of many subjects. . Therefore, when an X-ray imaging target patient (subject) is positioned on the X-ray imaging apparatus 1, the actual dentition is positioned, for example, inside the theoretical dentition as shown in FIG. In this case, there is a difference between the tomographic position at the center of the dentition of the patient (subject) to be X-rayed and the position of the basic tomogram of the theoretical dentition (the position of the standard imaging trajectory). Therefore, from the plan view of the dentition shown in FIG. 3B, the tomographic position that the user (doctor) of the X-ray imaging apparatus 1 wants to actually observe from the dentition of the patient (subject) to be X-rayed is shown. It is difficult to choose.

  Therefore, in the present invention, an impression of the dentition of an X-ray imaging target patient (subject), which is an actual panoramic tomographic image reconstruction process target, is collected in advance, and a camera-captured image of this impression is obtained by X-ray imaging. The user (doctor) of the apparatus 1 is used for screen display for selecting a desired tomographic position.

[Configuration of each part of X-ray imaging apparatus]
Returning to FIG. 1, the configuration of each part of the X-ray imaging apparatus 1 will be described.
The X-ray source 2 has a slit (not shown), and is generated by irradiating the subject positioned at the reference position for X-ray imaging of the X-ray imaging apparatus 1 via this slit. An object is irradiated with a slit-shaped beam (X-ray beam) at a predetermined timing. Here, the reference position for X-ray imaging at which the subject is positioned indicates, for example, a predetermined position of a chin rest on which a person to be imaged places a chin. Corresponding to the positioning of the subject to the reference position for X-ray imaging, a standard tomographic position is predetermined in the X-ray imaging apparatus 1. The trajectory when the standard tomographic position is viewed from the rotation axis direction of the turning drive means 4 of the X-ray imaging apparatus 1 is the standard imaging trajectory.

  The X-ray imaging means 3 receives X-rays emitted from the X-ray source 2 and transmitted through the subject, and images a portion of the subject through which the X-rays are transmitted at a predetermined frame rate. The X-ray imaging means 3 is an X-ray image sensor, an X-ray detector, or a combination thereof. Here, the image sensor is, for example, a CCD (Charge Coupled Device) image sensor, a CMOS image sensor, a TFT (Thin Film Transistor) sensor, a CdTe sensor, or the like. The X-ray detector is an X-ray image intensifier (I.I.), a flat panel detector (FPD), or the like. In the present embodiment, the X-ray imaging unit 3 will be described as a CMOS image sensor. In this case, one pixel size can be set to 100 μm, for example.

  The turning drive means 4 holds the X-ray source 2 and the X-ray imaging means 3 on the arm 4a at a predetermined interval, and turns so that the arm 4a is rotated at a predetermined angular velocity by driving a motor, an actuator or the like. Let This interval is set to, for example, 30 cm to 1 m so that the subject K is accommodated between the X-ray source 2 and the X-ray imaging means 3. In addition, the irradiation part of the X-ray source 2 and the light-receiving surface of the X-ray imaging means 3 are arranged to face each other. Further, the arm 4a is configured to be rotatable around the rotation center O, and further configured to be able to perform a sliding operation for moving the rotation center O. As a result, the X-ray imaging unit 3 can capture a tomographic image in any direction around the subject while the X-ray source 2 and the X-ray imaging unit 3 maintain a predetermined interval.

  The turning drive means 4, the X-ray source 2, and the X-ray imaging means 3 are controlled by a controller (not shown), and the X-ray source 2 emits X-rays while the turning drive means 4 turns the arm 4a. The imaging is repeated, and in synchronization with the X-ray irradiation timing, the X-ray imaging unit 3 continuously captures a frame image (simple X-ray imaging image) as an X-ray image of the subject and outputs it to the A / D conversion unit 5 To do.

  The A / D conversion means 5 acquires the output signal (frame image) of the X-ray imaging means 3, performs A / D conversion (analog to digital translation), and outputs the output signal (A / D converted) of the X-ray imaging means 3 ( Frame image) is stored in the image storage means 6. The panorama image processing means 7 reads out the frame image from the image storage means 6 and stores the result of image reconstruction processing using the frame image in the processed image storage means 8 as a processed image. That is, the panoramic image processing means 7 acquires the frame image converted and output by the A / D conversion means 5 and processes it.

  The image storage means 6, the panoramic image processing means 7, the processed image storage means 8, and the entire image display storage means 9 can be realized by, for example, a general computer (computer), and a CPU (Central Processing Unit). A unit (RAM), a random access memory (RAM), a read only memory (ROM), a hard disk drive (HDD), and an input / output interface.

  The image storage means (frame image storage means) 6 stores a frame image as an X-ray image of a subject imaged by the X-ray imaging means 3 and subjected to A / D conversion. Etc. This frame image is an X-ray imaging result of a subject at a standard tomographic position determined in advance corresponding to the positioning of the subject to a reference position for X-ray imaging.

  The processed image storage means 8 stores a plurality of processed images generated as a result of the reconstruction process by the panorama image processing means 7, and is composed of a general image memory, a hard disk, and the like. This processed image storage means 8 is used for processing such as image synthesis by the panorama image processing means 7.

  The all-image display storage unit 9 stores a tomographic image (a tomographic image corresponding to a designated tomographic image) that is generated as a result of the reconstruction process by the panoramic image processing unit 7 and is to be displayed on the first output unit 10. It is composed of a general image memory or the like. This tomographic image is represented by a luminance value, for example.

  The first output means (display means) 10 is a monitor that displays a panoramic tomographic image. For example, a CRT (Cathode Ray Tube), a liquid crystal display (LCD), a PDP (Plasma Display Panel), an EL (EL) Electronic Luminescence). The first output means 10 can continuously output the tomographic images processed by the panoramic image processing means 7 for each tomogram corresponding to the tomographic image specified and generated and displayed by the first input means 18. .

The first input means 18 includes, for example, a mouse, a keyboard, a disk drive device, and the like. In the present embodiment, the first input means 18 uses the panoramic tomography reconstructed with respect to the basic tomography b ₀ as information input to the panoramic image processing means 7 in order to designate a tomographic image to be generated and displayed. An input of a two-dimensional coordinate value indicating a region of interest (ROI) on the image and operation input information for designating a tomography (fault region) included in the region of interest is accepted.

  For this purpose, the first input means 18 includes a GUI (graphical user interface) for inputting data to a computer using a pointing device such as a mouse or a touch panel, and the operation position coordinates of the pointing device are used for panorama. Input to the image processing means 7. As a result, the panoramic image processing means 7 draws the trajectory of the tomographic position based on the operation position coordinates input from the first input means 18 and outputs it to the first output means 10.

  The panorama image processing means 7 acquires a frame image as an output signal of the A / D conversion means 5 and stores it in the image storage means 6. This panorama image processing means 7 has a function of image reconstruction processing and a function of displaying an image for the user to select a tomographic position. The panoramic image processing means 7 is arbitrarily designated as a function of image reconstruction processing by developing a plurality of frame images stored in the image storage means 6 on the processed image storage means 8 and superimposing them in the horizontal direction. Reconstruct a panoramic tomographic image of the tomographic position. The reconstructed tomographic image is output to the first output means 10 via the entire image display storage means 9.

In addition, the panoramic image processing means 7 performs a region of interest (based on the horizontal direction value of the two-dimensional coordinate value of the panoramic tomographic image B ₀ input by the first input means 18 as preprocessing of the image reconstruction processing. receiving a selection of ROI), further, based on the tomographic position specified by the fault zone selection screen to be described later, it extracts a frame image constituting a region of interest among all frame images constituting the panoramic tomographic image B _0. Details of the processing of the panorama image processing means 7 will be described later.

  An impression material for copying the type of the subject is attached to the auxiliary tool (positioning auxiliary tool) 12. The auxiliary tool 12 is detachable from the X-ray imaging apparatus 1. As the auxiliary tool 12, for example, an auxiliary commercially available instrument for positioning a subject that is an X-ray imaging target with respect to the X-ray imaging apparatus 1 can be used.

  The camera 11 captures an impression copied on an impression material attached to the auxiliary tool 12, and is composed of a general-purpose camera having a digital output. The camera 11 photographs the subject's impression from right above by aligning it with the standard photographing trajectory indicating the standard tomographic position as viewed from the rotation axis direction of the turning drive means 4. For this purpose, the camera 11 is fixed to a predetermined position of the arm 4a in a state of being aligned with a reference position for X-ray imaging and a standard imaging trajectory. An image acquired by this shooting is simply referred to as a camera shot image.

  The image storage means 13, the camera image processing means 14, the processed image storage means 15, the whole image display storage means 16, the second output means 17 and the second input means 19 are configured for impression camera-captured images. , Image storage means 6, panoramic image processing means 7, processed image storage means 8, all-image display storage means 9, first output means 10 and first input means, each of which is configured for the above-described X-ray image. 18 is the same. Therefore, the description will be omitted as appropriate, and different functions will be described. It should be noted that the configuration for the camera-captured image of these impressions and the configuration for the X-ray captured image can be shared by a common configuration without being separated.

The image storage unit 13 stores a camera-captured image of an impression captured by the camera 11.
The camera image processing unit 14 reads a camera-captured image of the designated impression from the image storage unit 13 based on a command input from the first input unit 18 via the panoramic image processing unit 7. Then, the read camera-captured image is developed in the processing image storage unit 15 and, for example, processing such as movement, rotation, enlargement / reduction, and the like is performed based on the command. Note that, for example, a similar process may be performed based on a command input from the second input unit 19.

  The all-image display storage unit 16 stores a camera-captured image (camera-captured image of a specified impression) generated as a processing result of the camera-image processing unit 14, and uses the camera-captured image as a camera image. Similar to the processing means 14, the data is output to the second output means 17 based on the command. Note that the camera-captured image may be output to the first output means 10.

  The second output means 17 displays an impression camera image. The second output unit 17 does not need to be a device independent of the first output unit 10, and may display another display mode using the display screen of the first output unit 10. You may make it display on a one part area | region of all the screens which 1 output means 10 displays on a small screen.

  The second input means 19 is for inputting necessary information such as a command for operating the operation of the camera 11 and a file name of the image in order to acquire and store an image captured by the camera. In the present embodiment, as an example, an “impression shooting” button is displayed on the monitor of the second output means 17, and camera shooting is performed by clicking this with a mouse or the like.

  In this X-ray imaging apparatus 1, the panoramic image processing means 7 superimposes the trajectory of the tomographic position of the subject viewed from the rotation axis direction of the turning drive means 4 on the camera photographed image to the first output means 10. Outputs, receives selection and deformation instructions for the trajectory of the displayed tomographic position, obtains an overlap width of a plurality of frame images g based on information of the selected and deformed trajectory, and selects a tomographic trajectory of the selected and deformed trajectory A panoramic tomographic image is generated by reconstructing the image.

[Flow of work and processing of X-ray equipment]
Next, a work flow and a process flow in the X-ray imaging apparatus 1 will be described with reference to FIG. FIG. 6 is a flowchart showing a work flow and a process flow using the X-ray imaging apparatus according to the embodiment of the present invention. The flow of work performed by the user of the X-ray imaging apparatus 1 can be roughly divided into three phases. The first phase is a first preliminary operation for acquiring a captured image of an impression taken from a subject (patient) that is an X-ray imaging target by the X-ray imaging apparatus 1. The second phase is a second preliminary operation for acquiring a panoramic image of a subject (patient) that is an X-ray imaging target. The third phase is a main operation in which the X-ray imaging apparatus 1 performs a selection operation for generating an ROI image and a navigation display.

<First phase>
First, the user collects an impression of the dentition of the subject (patient) using the auxiliary material with impression material (step S1), and attaches the auxiliary material with impression material that has acquired the impression to the X-ray imaging apparatus 1 (step S2). . Then, the user captures the collected impression from above with the camera 11 (step S3), and captures the camera captured image into the X-ray imaging apparatus 1 (step S4).

<Second phase>
Next, the user introduces a subject (patient) and positions it on the X-ray imaging apparatus 1 (step S5). Then, the user X-rays the panoramic image of the dentition with the X-ray imaging apparatus 1 (step S6). The panoramic image of the taken standard tomographic position is displayed on the monitor (first output means 10) (step S7). In step S5 described above, the method of positioning the subject (patient) on the X-ray imaging apparatus 1 is performed, for example, by removing the auxiliary tool with impression material and fixing the patient to the chin rest 26. In addition, it can also be positioned by having the patient bite the auxiliary tool with impression material.

<Third phase>
The X-ray imaging apparatus 1 displays a panoramic image on a monitor (first output means 10), and the second output means 17 displays a tomographic image currently selected on a tomographic area selection screen for displaying an impression camera captured image. The trajectory representing the position is superimposed and displayed for navigation (step S7). The initial state of the trajectory representing the currently selected tomographic position is a basic tomographic trajectory (standard imaging trajectory) determined in advance by the X-ray imaging apparatus 1 as shown in FIG.

  Here, the user can select the ROI on the monitor and select a desired tomographic position on the screen of the second output means 17. The X-ray imaging apparatus 1 determines whether or not a ROI slice is newly selected (step S9). When a ROI slice is newly selected (step S9: Yes), the X-ray imaging apparatus 1 reconstructs a tomographic image of the newly selected tomographic position (step S10), as shown in FIG. In this way, the reconstructed panoramic image is displayed again on the monitor (first output means 10) (step S11), and the process returns to step S8. Note that when the end command is executed without newly selecting a tomography (step S9: No), the X-ray imaging apparatus 1 ends the process.

(Auxiliary tool configuration example)
FIG. 7 is a plan view showing an example of an auxiliary tool attached to the X-ray imaging apparatus according to the embodiment of the present invention. The auxiliary tool 12 is made of, for example, a transparent resin and is formed in a U shape corresponding to the dentition, and an impression material 21 is attached to the U shape portion as shown in FIG. FIG. 8 shows a state where the impression 22 has already been copied. The auxiliary tool 12 is provided with a hole at an appropriate position of the U-shaped portion so that the impression material is easily fixed. Further, an iron ball 602 is embedded at the position of the median line 601 of the U-shaped part. As shown in FIG. 7, the auxiliary tool 12 is provided with a locking portion having a screwable hole at a position where the impression material is not attached.

(Auxiliary tool alignment)
The position where the auxiliary tool 12 is attached to the X-ray imaging apparatus 1 is a position where alignment is performed as follows. That is, the iron ball 602 embedded at the position of the median line 601 of the auxiliary tool 12, the median line of the X-ray imaging apparatus 1, and the apex (reference position) on the front tooth side of the imaging trajectory of the X-ray imaging apparatus 1. It is a position where the positions match. Note that the X-ray imaging apparatus 1 of the present embodiment has a position between the median line when the subject is fixed in the X-ray imaging apparatus 1 and the apex (reference position) on the front tooth side of the imaging trajectory of the X-ray imaging apparatus 1. It is assumed that it is verified by a 3D phantom to be described later.

(Camera mounting position)
As described above, the camera 11 is attached to a position where the auxiliary tool 12 can be imaged from directly above in accordance with the position where the auxiliary tool 12 is mounted on the X-ray imaging apparatus 1. Details of the mounting position will be described with reference to FIG. FIG. 9 shows an example of the appearance of the X-ray imaging apparatus 1 shown in the block diagram of FIG. In the X-ray imaging apparatus 1 shown in FIG. 9, the turning drive means 4 is connected to a support column 24 provided on a base 23 fixed to the floor so as to move up and down. Here, since the appearance is shown in a simplified manner, the X-ray source 2 and the X-ray imaging means 3 held by the arm 4a of the turning drive means 4 are housed in dedicated units, respectively, and are shown in FIG. Further, the control unit, the operation unit, and the display unit of the panoramic image processing means 7 and the like are assumed to be collectively stored in the controller 25 above the support column 24.

  As shown in the enlarged view of the region indicated by the broken line 603 in FIG. 9, the X-ray imaging apparatus 1 includes a chin rest 26 that can move up and down for positioning a subject (patient) during X-ray imaging. In positioning the subject (patient) in the second phase, for example, the auxiliary tool 12 is removed from the chin rest 26, and the person is positioned with the first central incisor with the right side as the front in FIG. At this time, the forehead is fixed by a forehead support 27 that can move back and forth, and the side of the head is fixed by a side head support 28 that can move left and right.

  On the other hand, in the first phase described above, when acquiring a camera-captured image of an impression, the auxiliary tool 12 is fixed horizontally to the chin rest 26. When fixing, the iron ball 602 embedded in the position of the median line 601 of the auxiliary tool 12 and the median line of the X-ray imaging apparatus 1 are matched. In this state, the camera mounting is such that a line connecting the iron ball 602 embedded at the position of the median line 601 of the auxiliary tool 12 and the lower surface of the arm 4a in the vertical direction intersects the lower surface of the arm 4a. The camera 11 is attached to the position 604.

More specifically, the camera attachment position 604 does not have to be the lens center itself of the camera 11, and the impression 22 and the iron ball 602 may be included in the angle of view of the camera 11 as shown in FIG. 10. In FIG. 10, H _b represents an actual distance within the angle of view in the vertical direction (hereinafter simply referred to as height) of the U-shaped portion of the auxiliary tool 12 fixed to the X-ray imaging apparatus 1. Here, the subscript “b” indicates an actual distance. In FIG. 10, h represents an example of the actual distance from the camera 11 to the auxiliary tool 12. In this embodiment, as an example, the distance is measured in units of mm.

The camera-captured image 605 is acquired in a state where the impression material 21 is not attached to the auxiliary tool 12 corresponding to the angle of view shown in FIG. H _c that indicates the size of the camera captured image 605 shows the vertical U-shaped portion of the image of the aid 12 (hereinafter, simply referred to as height) that represent in pixels (pixel) basis. Here, c indicates a camera image. Further, W _c that indicates the size of the camera captured image 605, the lateral U-shaped portion of the image of the aid 12 (hereinafter, simply referred to as width) shows those represent in pixels (pixel) basis. A calculation formula for obtaining the correspondence between the actual size of the auxiliary tool 12 and the number of pixels of the camera photographed image 605 will be described later.

  FIG. 11 shows an example of the capturing process of the camera-captured image 605 corresponding to step S4 described above. In this case, the user clicks the “impression imaging” button displayed on the monitor (second output means 17) of the X-ray imaging apparatus 1 (step S21). In response to this, the X-ray imaging apparatus 1 transfers the camera captured image 605 captured by the camera 11 and stores it in the image storage means 13.

When another tomography is to be reconstructed based on the X-ray panoramic tomographic image B ₀ , the basic tomographic position that is the original in the reconstruction is the same as the standard imaging trajectory in the set imaging mode. Therefore, the currently displayed tomographic position can be obtained by arranging the shooting trajectory on the camera image as follows.

  Corresponding to step S8 described above, an initial state of the navigation display on the tomographic area selection screen will be described with reference to FIG. In the initial state, the imaging trajectory display processing process includes the following steps in more detail. First, the X-ray imaging apparatus 1 reads a camera-captured image by the panoramic image processing means 7 (step S31), and reads an imaging trajectory coordinate table corresponding to the imaging mode (step S32). In the present embodiment, the photographing mode has a standard panorama mode for adults and a panorama mode for children. The X-ray imaging apparatus 1 includes a table in which imaging trajectory coordinate values used in the standard panorama mode for adults are registered in advance (simply referred to as a standard table) and a table in which imaging trajectory coordinate values used in the panorama mode for children are registered in advance. (Simply referred to as a child table) is stored in the storage means in advance. Here, it is assumed that the shooting trajectory coordinate values are registered based on a verification 3D phantom described later. Note that the order of step S31 is not limited as long as it is before step S34, and parallel processing is also possible.

  Subsequent to step S32, the X-ray imaging apparatus 1 calculates imaging trajectory coordinate values to be arranged on the camera imaging image (step S33). This process is a process of converting a coordinate value corresponding to an actual distance on the verification 3D phantom described later into a coordinate value on the image (a pixel value on the screen). If the camera 11 is fixed and the correspondence between the actual size and the pixel value is not changed as in the present embodiment, it can be converted into a pixel value at the stage of the stored table.

  Subsequently, the X-ray imaging apparatus 1 places the calculated coordinate values on the camera captured image (step S34). That is, drawing is performed with CG or the like at the position of the calculated coordinate value. Then, the X-ray imaging apparatus 1 displays the tomographic position drawn on the second output means 17 based on the arranged coordinate values (step S35). Although the CG image used for drawing is not particularly limited, as shown in FIG. 17, for example, relatively large dots (points) as many as the number of teeth and lines connecting the points can be used. The line is not limited to a straight line, but may be a smoothly interpolated curve or the like. The number of points is not limited to this.

(Verification phantom)
As described above, the X-ray imaging apparatus 1 is configured so that the alignment is completed when the auxiliary tool 12 is mounted. A verification 3D phantom that supports this will be described with reference to FIGS. 13 and 14. FIG. This verification is performed after the X-ray imaging apparatus 1 is manufactured and made usable before the X-ray imaging apparatus 1 is used by a user. Therefore, it does not appear in the work flow or processing process using the X-ray imaging apparatus 1.

  FIG. 13 shows an example of a bird's eye view of the 3D phantom 606. The 3D phantom 606 is the highest plane on the left side in FIG. 13, and becomes lower toward the right side, the upper side, and the lower side. The 3D phantom 606 is created corresponding to the standard imaging trajectory 607 of the X-ray imaging apparatus 1. In the standard imaging trajectory 607, the right half in FIG. 13 corresponds to the dentition, and the left half corresponds to the jaw of the skull or the like.

In FIG. 13, intersections (a total of 25 locations) between the straight line indicated by reference numeral 608 and the standard imaging trajectory 607 correspond to imaging trajectory coordinates registered in advance in the standard table. The photographing trajectory coordinates are based on the origin 0. Let that value be (X ₀ , Y ₀ ). The position of the upper intersection in FIG. 13 from the origin 0 is shown as “1,..., 12” in order, and is called “Left No. 1,..., Left No. 12”, and the coordinate values of these intersections are expressed as (X _L1 , Y _L1 ),..., (X _L12 , Y _L12 ). Similarly, the position of the lower intersection in FIG. 13 from the origin 0 is indicated by “1,..., 12” in order, and is called “right first,..., Right twelfth”. X _R1 , Y _R1 ),..., (X _R12 , Y _R12 ).

  In FIG. 14, a child's imaging trajectory 609 is shown on a 3D phantom 606. The child's imaging trajectory 609 is the same as it is only smaller than the standard imaging trajectory 607, and therefore the description thereof will be omitted. Hereinafter, description will be given using the standard imaging trajectory 607 shown in FIG.

  Next, alignment between the standard imaging trajectory 607 and the auxiliary tool 12 will be described with reference to FIG. In the X-ray imaging apparatus 1, the origin 0 of FIG. 13 which is one point of the standard imaging trajectory 607 is aligned with the iron ball 602 of the auxiliary tool 12 shown in FIG. FIG. 15 is a diagram showing the relationship between the actual size of the auxiliary tool 12 corresponding to the actual object and its plane coordinates.

The actual size of the auxiliary tool 12 is defined as shown in FIG. Here, as described above, _Hb represents the actual distance within the angle of view at the height of the U-shaped portion of the auxiliary tool 12 fixed to the X-ray imaging apparatus 1. W _b represents the actual distance within the angle of view in the width of the U-shaped portion of the auxiliary tool 12. The origin of the plane coordinates is set to the position (0, 0) shown in FIG. At this time, indicating the actual size in the height direction of the U-shaped portion to the position coordinates of the iron ball 602 relative to the origin of the plane coordinate (0,0) (x-coordinate) in H _a. Similarly, show the actual size in the width direction of the U-shaped portion to the position coordinates of the iron ball 602 (y-coordinate) in W _a.

From the relationship between the actual size of the auxiliary tool 12 shown in FIG. 15 and the number of pixels of the camera-captured image 605 that is the image of the auxiliary tool 12 shown in FIG. 10, as shown in Expression (1), the length L per pixel _p [mm / pixel] can be obtained.

_Lp = _Wb / _Wc ... Formula (1)

A method of calculating the shooting trajectory coordinate value to be arranged on the camera shot image in the above-described step S33 will be described using this equation (1). As shown in FIG. 15, when the distance from the origin (0, 0) of the plane coordinates to the iron ball 602 at the median position of the auxiliary tool 12 is the width W _a [mm] and the height H _a [mm]. That can be paraphrased as follows. That is, when the origin (0, 0) of the plane coordinate shown in FIG. 15 is replaced with the coordinate value (X ₀ , Y ₀ ) of the origin 0 of the 3D phantom 606 shown in FIG. The actual width from the actual size value Y ₀ [mm], which is the y coordinate) to the iron ball 602, is W _a [mm]. Similarly, the length (height) from the actual dimension value X ₀ [mm], which is the x coordinate of the origin (0, 0) of the plane coordinates, to the iron ball 602 is H _a [mm].

  Therefore, in the camera-captured image of the auxiliary tool 12 shown in FIG. 10, if the origin (0, 0) of the plane coordinates is set to the same position as in FIG. 15, the x coordinate of the origin (0, 0) of the plane coordinates is The number of pixels in the width direction to the position of the image of the iron ball 602 at the median position of the assisting tool 12 is calculated by the equation (2) by using the equation (1) described above. Similarly, the number of pixels in the height direction from the y coordinate of the origin (0, 0) of the plane coordinate to the position of the image of the iron ball 602 at the median position of the auxiliary tool 12 is calculated by Expression (3). become.

W _a / L _p (pixel) (2)
H _a / L _p (pixel) ... Formula (3)

From the origin (0, 0) = origin 0 (X ₀ , Y ₀ ) to the respective intersections of the standard imaging trajectory 607 and the straight line 608 shown in FIG. 13 based on the plane coordinates defined in FIGS. The actual size of the horizontal distance (height) and the vertical distance (width) can be calculated. An example is shown in Table 1. It is assumed that the calculated value is an absolute value when calculating the distance in the horizontal direction and the vertical direction.

By drawing the distance [mm] in the horizontal direction and the vertical direction shown in Table 1 by the length L _p [mm / pixel] per pixel shown in the above equation (1), the image is drawn on the camera photographed image. It is possible to calculate a pixel position necessary for the operation. This converted value is shown in Table 2.

  Next, an example of the tomographic selection and display process of the region of interest shown in steps S9 to S11 will be described with reference to FIG. When the X-ray imaging apparatus 1 receives a display screen selection instruction from the first input unit 18 by a user operation, the X-ray imaging apparatus 1 sets a desired tomographic area on the monitor of the first output unit 10 or the second output unit 17. The fault area selection screen is displayed. At this time, as shown in FIG. 17A, the basic tomogram (standard imaging trajectory) is superimposed and displayed on the impression camera image. In this way, by displaying the basic tomography (standard imaging trajectory) of panoramic imaging on the impression camera imaging image, the user can perform X-ray imaging of the actual dentition of the subject (patient) to be X-rayed. It is possible to clearly know how much deviation has occurred from the basic fault set in advance in the apparatus 1.

  Then, on the tomographic area selection screen displayed on the monitor, the user matches the point of the basic tomography (standard imaging trajectory) with the tomography of the region of interest desired by the user by operating the mouse (step S41). The position information of the point moved by the operation is input from the first input unit 18 to the panoramic image processing unit 7. The panorama image processing means 7 draws the trajectory of the tomographic position based on the acquired position coordinates and outputs it to the first output means 10 as shown in FIG. The user can perform delicate mouse operations by confirming the trajectory displayed after the movement.

  Then, the user clicks a “setting” button (not shown) displayed on the screen on the tomographic area selection screen with the mouse (step S42). Thereby, the X-ray imaging apparatus 1 reconstructs the image of the tomographic area of the selected region of interest by the panoramic image processing means 7 and displays the panoramic image as a processing result on the first output means 10 (monitor). (Step S43).

[Functional block of image processing means for panorama]
FIG. 18 is a block diagram showing functions of the panoramic image processing means of the X-ray imaging apparatus according to the embodiment of the present invention. As shown in FIG. 18, the panorama image processing means 7 is roughly provided with a tomographic area selection receiving means 40, an image reconstruction means 50, and an image size correction means 60. The processed image storage unit 8 stores a camera-captured image 31, a standard table 32, and a child table 33 as information referred to by the panoramic image processing unit 7.

  The camera captured image 31 is an image similar to the camera captured image 605 shown in FIG. However, as illustrated in FIG. 8, it is an image of the auxiliary tool 12 in a state where the impression material 21 is attached and the impression 22 is copied.

As shown in FIG. 13, the standard table 32 is a table that stores coordinate values indicating intersection points (a total of 25 locations) between the straight line indicated by the reference numeral 608 and the standard imaging trajectory 607 in the 3D phantom 606. It has a storage structure as shown in Table 1. In addition, since the 1st to 8th coordinates correspond to the position of the dentition on both the left and right, the 9th to 12th coordinates may not be used.
The child table 33 is a table storing the coordinate values described with reference to FIG.

  As shown in FIG. 18, the tomographic area selection receiving means 40 includes a camera image reading means 41, a table reading means 42, a coordinate value calculating means 43, a drawing means 44, a synthesizing means 45, and a point change receiving means. 46.

The camera shot image reading unit 41 reads the designated camera shot image 31 from the processed image storage unit 8 and outputs it to the synthesis unit 45.
The table reading means 42 reads a specified table (standard table 32 or child table 33) from the processed image storage means 8 and outputs it to the coordinate value calculation means 43.

  The coordinate value calculation unit 43 calculates a pixel position necessary for drawing on the camera image. The coordinate value calculation unit 43 calculates a conversion value as shown in Table 2 on the basis of the above formulas (1) to (3), and outputs the calculation result to the drawing unit 44.

The drawing unit 44 draws the trajectory of the tomographic position of the subject calculated by the coordinate value calculation unit 43.
The synthesizing unit 45 generates a tomographic area selection screen by synthesizing the trajectory of the tomographic position of the subject drawn by the drawing unit 44 and the camera captured image read by the camera captured image reading unit 41, and generates a tomographic area selection screen. 10 is output.

  The drawing unit 44 and the combining unit 45 are configured by, for example, a GPU (Graphics Processing Unit), a CPU or an FPGA (Field Programmable Gate Array), and a predetermined program is developed on the RAM and executed. Fulfills the function.

  The point change accepting means (change accepting means) 46 accepts an instruction for selection and deformation for the trajectory of the tomographic position displayed on the first output means 10 from the first input means 18, and draws the selected and deformed trajectory. It instructs the drawing means 44. Here, the information on the selected and deformed trajectory is output to the image reconstruction unit 50. The point change accepting unit 46 performs processing related to the first input unit 18 (GUI).

The image reconstruction means 50 constructs a panoramic tomographic image B ₀ in the initial state in order to accept the selection of the region of interest (ROI) as a premise for displaying the tomographic area selection screen. That is, when the image reconstruction unit 50 superimposes the frame images g stored in the image storage unit 6 in combination, the image reconstruction unit 50 changes the combination of the frame images g as appropriate so that the panoramic tomographic image B corresponding to the basic tomography b ₀ is obtained. Generate ₀ .

Further, when the image reconstruction unit 50 acquires information on the trajectory selected and deformed from the point change accepting unit 46, the image reconstruction unit 50 configures the panoramic tomographic image B ₀ based on the information on the selected and deformed trajectory. The overlap width of a plurality of frame images g is obtained, and the data of each frame image g is superimposed on the memory, thereby reconstructing a tomographic image of the selected and transformed trajectory (specified tomographic area). The panoramic tomographic image B ₀ generated by the image reconstructing unit 50 and information on the reconstructed tomographic image are output to the image size correcting unit 60.

  The image size correcting means 60 receives the object from the first input means 18 and, based on the selected and deformed trajectory information, the subject according to the deviation between the selected and deformed trajectory position and the standard tomographic position. The tomographic image reconstructed by the image reconstructing means 50 at the position of the selected or deformed trajectory is enlarged or reduced to correct the image size corresponding to the assumed image size when there is no deviation. To do. Here, the image size correcting unit 60 includes a vertical direction correcting unit 61 and a horizontal direction correcting unit 62.

  The vertical direction correction unit 61 corrects the vertical image size, and the horizontal direction correction unit 62 corrects the horizontal image size. The principle of correction for enlarging / reducing the image size (hereinafter simply referred to as the size correction principle) will be described with reference to FIGS. The size correction principle includes a principle considering the positional relationship between the subject and the X-ray source 2 (size correction principle A), and a positional relationship between the selected tomographic area (region of interest) and the rotation center O of the turning drive means 4. There are two types: a principle that considers (size correction principle B).

(Premise of the example shown in FIG. 19)
In the X-ray imaging apparatus 1, since the X-ray source 2 and the X-ray imaging unit 3 are held by the arm 4 a of the turning drive unit 4, the distance between the X-ray source 2 and the light receiving surface of the X-ray imaging unit 3 is It is assumed that the X-ray source 2 and the X-ray imaging means 3 rotate around the rotation center O. In FIG. 19, a standard tomographic position 701 (a standard imaging trajectory at a certain moment; a position of a broken line) which is a normal tomographic position is a position away from the rotation center O by a distance r. The X-ray imaging unit 3 is adjusted so that when an object at the standard tomographic position 701 is imaged, an object image of an appropriate size is acquired and displayed at the appropriate size. Here, the distance between the X-ray source 2 and the standard tomographic position 701 is a, and the distance between the X-ray imaging means 3 and the standard tomographic position 701 is b.

(Size correction principle A)
The size correction principle A is that when the subject of the X-ray source 2 and the X-ray imaging unit 3 approaches the fixed one X-ray source 2, the image of the subject imaged by the other X-ray imaging unit 3 Is enlarged by that amount, and conversely, when the subject is moved away from the X-ray source 2, the size of the image is reduced.

  As shown in FIG. 19, the position 702 (thick line position) of the dentition in the region of interest is shifted by a predetermined distance L from the standard tomographic position 701 to the rotation center O side (left side in FIG. 19). In this case, when the position 702 of the dentition in the region of interest is brought closer to the fixed X-ray source 2 (moved to the left in FIG. 19), the size of the image captured by the X-ray imaging unit 3 is The image size is enlarged as compared with a predetermined image size in the X-ray imaging apparatus 1.

  More specifically, the X-ray imaging apparatus 1 assumes the following relationship with respect to a subject assumed to be at the standard tomographic position 701 (subject at a normal position). That is, in FIG. 19, the subject at the correct position is photographed on the light receiving surface of the X-ray imaging means 3 at a size (a + b) / a times larger than the actual size. The image is displayed larger than the subject size. Therefore, (a + b) / a is referred to as an enlargement ratio, and this is represented by M.

A subject (subject at the position of the region of interest) assumed to be at the position 702 of the dentition of the region of interest is similarly magnified and photographed on the light receiving surface of the X-ray imaging unit 3. It represents the magnification at this time is M _1.

Since the enlargement ratio M ₁ is larger than the enlargement ratio M, the enlargement ratio M _m resulting from the shift of the position of the dentition from the normal position to the X-ray source 2 side is expressed by Expression (6). The

In other words, the position of the region of interest, due to the offset from the normal position by a distance L, the image of the object is displayed horizontally even vertical direction to expand M _m times only unnecessarily.

(Size correction principle B)
The size correction principle B is that when the subject of the X-ray source 2 and the X-ray imaging unit 3 approaches the fixed rotation center O, the size of the subject image captured by the X-ray imaging unit 3 is If the subject is reduced by that amount and, on the contrary, the subject is moved away from the rotation center O, the size of the image is enlarged. Therefore, the size correction principle B is a principle that affects the image size only in the horizontal direction of the subject image.

  As described above, the position 702 of the dentition of the region of interest is shifted from the standard tomographic position 701 by the distance L toward the rotation center O side. In other words, the position 702 of the dentition in the region of interest is separated from the rotation center O by a predetermined distance (Lr) to the right in FIG. In this case, when the position 702 of the dentition of the region of interest is brought close to the rotation center O (moved to the left in FIG. 19), the size of the image captured by the X-ray imaging unit 3 is the X-ray imaging apparatus. Therefore, the image size is reduced as compared with the size of the image determined in advance.

  More specifically, in the X-ray imaging apparatus 1, when the image is reconstructed using a frame image of a subject (subject at a normal position) assumed to be at the standard tomographic position 701, the enlargement of Expression (4) described above is performed. It is displayed correctly at the rate M. However, as shown in FIG. 19, the position 702 of the dentition in the region of interest has approached the rotation center O. Therefore, when the image is similarly reconstructed using the frame image, the image of the subject at the position of the region of interest is The image is not displayed correctly at the enlargement factor M, and is displayed with a smaller size than the assumed enlargement factor M. The reduced ratio N at this time is expressed by Expression (7).

  In summary, the size correction principle A (formula (6)) may be used for vertical correction, and the size correction principle A and the size correction principle B (formula (6) and formulas) are used for horizontal correction. (7)) may be used. Therefore, the vertical direction correction unit 61 of the image size correction unit 60 multiplies the vertical size of the tomographic image reconstructed by the image reconstruction unit 50 by the vertical direction enlargement ratio v shown in Expression (8). The vertical size of the reconstructed tomographic image is corrected.

  Further, the horizontal direction correcting unit 62 multiplies the horizontal size of the reconstructed tomographic image by the horizontal enlargement factor h shown in Expression (9), thereby obtaining the horizontal size of the reconstructed tomographic image. Correct.

(Example shown in FIG. 20)
Next, a description will be given with reference to FIG. The example shown in FIG. 20 and the example shown in FIG. 19 are different in the position 702 (position of the thick line) of the dentition of the region of interest on the premise. That is, in the example shown in FIG. 20, the distance from the standard tomographic position 701 is shifted by the distance L to the X-ray imaging means 3 side (right side in FIG. 20). Further, the position 702 of the dentition in the region of interest is separated from the rotation center O by a predetermined distance (L + r) to the right in FIG.

  Except for these differences, the size correction principle can be derived in the same manner, and detailed description thereof will be omitted. According to the size correction principle in the example shown in FIG. 20, “a−L” is replaced with “a + L” in the equations (5), (6), and (8), and the equation (7) ) And (9), by replacing “r−L” with “r + L”, respectively, the corresponding relational expression can be derived.

  After the correction as described in the example shown in FIG. 19 or FIG. 20, the first output unit 10 can display the tomographic image whose image size is corrected as a panoramic tomographic image. Here, a display image example corresponding to the example shown in FIG. 20 is shown in FIG. In FIG. 21, for the purpose of corresponding to FIG. 20, the standard tomographic position 701, that is, the imaging trajectory is indicated by a broken line (inner line), and the dentition position 702 of the region of interest, that is, the deformed trajectory. Is indicated by a solid line (outer line). However, on the tomographic area selection screen, in the initial state, only the standard tomographic position 701 is displayed together with the impression, and subsequently, the position 702 of the dentition of the region of interest is displayed as a display of the result selected by the user. .

  The distance L shown in FIG. 21 is the deviation width L in the above-described equations (5) to (9). Here, for the sake of simplicity, it is assumed that the trajectory of the standard tomographic position 701 and the trajectory of the dentition position 702 of the region of interest are separated by a certain distance L at any position. In the panoramic image processing unit 7 of the X-ray imaging apparatus 1, for example, the information on the distance L can be acquired by the synthesizing unit 45 and the point change receiving unit 46 and notified to the image size correcting unit 60.

  In the example shown in FIG. 19 or FIG. 20, the image size correction means 60 uses the image vertical direction and the image horizontal in the desired tomographic image obtained when the frame image is tomographically reconstructed at the position of the dentition (region of interest). Correction is performed by applying a relational expression obtained by replacing the enlargement ratio or the sign of Expression (8) and Expression (9) to the image size in the direction. As a result, the same size as the tomographic image obtained in the normal tomographic area is displayed.

In particular,
Width of image obtained in normal fault area: W _s
Height of image obtained in normal fault area: H _s
Width of image obtained at dentition position (region of interest): W _r
Height of image obtained at position of dentition (region of interest): H _r
Then, the relational expressions of Expression (10) and Expression (11) are obtained.

_{H r} = H _s × v ... (10)
_{W r} = W _s × h ... (11)

Therefore, the following usage 1 and usage 2 are conceivable with respect to the vertical magnification v shown in equation (8) and the horizontal magnification h shown in equation (9).
(Application 1) The panorama image can be reconstructed by using the enlargement ratio calculated as in the equations (8) and (9).
(Application 2) By calculating the enlargement ratio at the position that is most in focus in the panoramic image, an image that is enlarged / reduced with respect to the normal tomographic area is displayed as a tomographic image after size correction. It can be clarified.

  From these ideas, for example, when the position 702 of the dentition in the region of interest is the tomographic position in focus, the image vertical direction and the image when the tomographic reconstruction is performed at the position 702 of the dentition in the region of interest. It is also possible to correct the horizontal image size to the actual size of the subject. This is equivalent to setting the enlargement ratio M of the above-described formula (4) to “1”.

A vertical correction rate (vertical size correction rate) v _s for correcting the image size in the image vertical direction and the image horizontal direction to the size of the subject when the tomographic reconstruction is performed at the dentition position 702 of the region of interest. The horizontal correction rate (horizontal size correction rate) h _s is expressed by Equation (12) and Equation (13), respectively.

The relationship when correcting to the subject size using the vertical size correction rate v _s and the horizontal size correction rate h _s for correcting to the actual size of the subject is as follows.
In particular,
Width of image obtained at dentition position (region of interest): W _r
Height of image obtained at position of dentition (region of interest): H _r
Image width at subject position: W '
Height at subject position: H '
Then, the relational expressions of Expression (14) and Expression (15) are obtained.

W ′ = W _r × h _s Formula (14)
_{H '= H r × v s} ... formula (15)

Thus, following application 3 with respect to the horizontal size correction factor h _s shown in vertical size correction factor v _s and the formula (13) shown in Equation (12) can be considered.
(Use 3)
By calculating the correction rate at the most focused position in the panoramic image, an image having the same size as the actual size of the subject can be displayed. Therefore, when the subject is, for example, a dentition, it is possible to obtain the formal size of the lesion from the display image.

  According to the present embodiment, the X-ray imaging apparatus 1 captures an impression collected in advance with the camera 11 and displays a basic tomogram (standard imaging trajectory) superimposed on the image. Therefore, the user can visually recognize the tomographic position actually obtained by panoramic imaging. In addition, the user can clearly recognize the degree of deviation between the basic tomography (standard imaging trajectory) and the tomographic position of the region of interest.

  Further, according to the present embodiment, the X-ray imaging apparatus 1 can accept an operation of selecting and deforming a tomographic position of a region of interest on a displayed captured image of an impression. Therefore, the user can easily specify a tomographic position suitable for diagnosis. For example, on the tomographic area selection screen, when the subject is a dentition, it is possible to specify an adjacent surface between teeth. When specifying adjacent surfaces between teeth, move the point toward the next point in the row direction of the dentition, or the width direction of the dentition so that the straight part between the points penetrates the adjacent surface of the teeth (Inside and outside of the dentition). Thereby, when the selected tomographic image is displayed, the user can observe the caries (tooth decay) on the adjacent surface. Further, since the X-ray imaging apparatus 1 can easily reconstruct a tomographic image at an arbitrary tomographic position, the exposure is minimal for the patient.

  Further, according to the present embodiment, the X-ray imaging apparatus 1 can calculate the image enlargement ratio of the region of interest from the deviation width between the basic tomography (standard imaging trajectory) and the tomographic position of the region of interest. . As a result, panoramic image reconstruction can be performed using the calculated enlargement ratio. It is also possible to clarify how much the dentition tomography (region of interest) is looking at an enlarged / reduced image with respect to the normal tomographic area by calculating the enlargement ratio at the position that is in focus. it can. Further, it is possible to correct the size of the enlarged / reduced image so as to be the actual size of the subject. From the above, it is clinically effective.

  Furthermore, according to the present embodiment, once the impression of the subject (patient) is photographed by the X-ray imaging apparatus 1, the photographed image of the subject (patient) can be captured even when the subject (patient) performs panoramic photography again. Can be reflected on the fault area selection screen. Moreover, if the auxiliary material with impression material used at the time of acquiring the camera-captured image is stored, the apparatus can be positioned in the same manner as the previous time if it is the same subject (patient). Furthermore, when this auxiliary tool with impression material is used again for positioning, the position of the previous tomographic plane can be grasped, so that there is reproducibility. At this time, the user can easily follow the change with time.

  As mentioned above, although embodiment of this invention was described, this invention is not limited to this, It can implement in the range which does not change the meaning. For example, in the present embodiment, the best mode in which the panoramic image processing unit 7 includes the image size correcting unit 60 has been described, but the image size correcting unit 60 is not an essential configuration. However, since the image size correcting means 60 can be applied to various uses and exert more excellent effects, the best mode is preferable.

  In the present embodiment, the X-ray imaging apparatus 1 includes the camera 11. However, the camera 11 is not indispensable, and the X-ray imaging apparatus 1 captures an image with an alignment apparatus including another camera. It can also be configured to acquire a camera image.

  In the present embodiment, the arm 4a of the turning drive means 4 is configured to be rotatable around the rotation center O, and further configured to be capable of sliding to move the rotation center O. In the X-ray imaging apparatus of the invention, a sliding operation for moving the rotation center O is not essential, and the arm 4a of the turning driving means 4 can be configured to perform only an operation for rotating around the rotation center O.

  Further, the relational expressions of the above formulas (10) and (11) can be used not only for a tomographic image after image reconstruction but also for a frame image before image reconstruction.

  Further, the display of the tomographic image in which the region of interest is reconstructed is not limited to a still image. For example, a tomographic image obtained by shifting the tomographic position in units of 0.1 mm from the inside to the outside of the dentition may be continuously displayed as a movie. In this case, in the display of the tomographic area selection screen (navigation display), the trajectory of the tomographic position corresponding to the movie display may be continuously displayed as the trajectory superimposed on the impression camera-captured image.

  In the present embodiment, the panoramic image processing means 7 has been described as having both a function of image reconstruction processing and a function of displaying an image for the user to select a tomographic position. You may make it provide.

  The panorama image processing means 7 executes a panorama image processing program that causes a general computer to execute the functions of the drawing means 44, the synthesis means 45, the point change accepting means 46, and the image reconstruction means 50. It can also be realized. This program can be provided via a communication line, or can be written on a recording medium such as a CD-ROM and distributed.

1 is a block diagram schematically showing a configuration of an X-ray imaging apparatus according to an embodiment of the present invention. It is explanatory drawing which shows the some tomography allocated so as to correspond to the standard dentition as a to-be-photographed object. It is a figure which shows an example of the input region of interest (ROI), Comprising: (a) shows ROI designated on the panoramic tomographic image, (b) shows each tomography of the depth direction corresponding to the designated ROI, respectively. ing. It is explanatory drawing which shows the process which the image processing means for panoramas of the X-ray imaging apparatus which concerns on embodiment of this invention extracts and reconstructs a frame image from ROI. It is explanatory drawing which shows an example of a dentition smaller than a standard dentition. It is a flowchart which shows the flow of a process using the X-ray imaging apparatus which concerns on embodiment of this invention, and the flow of a process. It is a top view which shows an example of the auxiliary tool with which the X-ray imaging apparatus which concerns on embodiment of this invention is mounted | worn. It is a top view which shows an example of the impression of the dentition extracted by the impression material adhering to the auxiliary tool shown in FIG. It is explanatory drawing of the attachment position of the camera with which the X-ray imaging apparatus which concerns on embodiment of this invention is provided. It is explanatory drawing of the correspondence of the arrangement | positioning of the camera with which the X-ray imaging apparatus which concerns on embodiment of this invention is provided, and a camera picked-up image. It is a flowchart which shows an example of the taking-in process of the camera picked-up image shown in FIG. 7 is a flowchart illustrating an example of a shooting trajectory display processing process as an initial state of the navigation display illustrated in FIG. 6. It is explanatory drawing which shows the standard imaging | photography trajectory corresponding to standard imaging | photography mode. It is explanatory drawing which shows the imaging trajectory for children corresponding to the imaging mode for children. It is explanatory drawing of the length and width | variety in real space of the auxiliary tool and iron ball which are positioned in the X-ray imaging apparatus which concerns on embodiment of this invention. 7 is a flowchart illustrating an example of a process for selecting and displaying a tomographic region of interest shown in FIG. 6. It is a figure which shows the example of a display of a tomographic area selection screen, Comprising: (a) has shown the standard imaging | photography trajectory, (b) has shown the trajectory transformed by input operation. It is a block diagram which shows the function of the image processing means for panoramas of the X-ray imaging apparatus which concerns on embodiment of this invention. It is explanatory drawing for demonstrating the case where a dentition is expanded and displayed rather than assumption. It is explanatory drawing for demonstrating the case where a dentition is reduced and displayed rather than assumption. It is explanatory drawing of the tomographic area selection screen when the position of the dentition of the region of interest is outside the standard tomographic position.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 X-ray imaging apparatus 2 X-ray source 3 X-ray imaging means 4 Rotation drive means 4a Arm 5 A / D conversion means 6 Image storage means (frame image storage means)
7 Image processing means for panorama 8 Processed image storage means 9 Whole image display storage means 10 First output means 11 Camera 12 Auxiliary tool (positioning auxiliary tool)
13 Image storage means (camera shot image storage means)
14 camera image processing means 15 processed image storage means 16 all image display storage means 17 second output means 18 first input means 19 second input means 21 impression material 22 impression 23 base 24 strut 26 chin rest 25 controller 27 forehead support 28 Side head support 31 Camera captured image 32 Standard table 33 Pediatric table 40 Tomographic area selection receiving means 41 Camera captured image reading means 42 Table reading means 43 Coordinate value calculating means 44 Drawing means 45 Compositing means 46 Point change receiving means 50 Image reconstruction Means 60 Image size correction means 61 Vertical direction correction means 62 Horizontal direction correction means

Claims (4)

An X-ray source that emits X-rays to a subject positioned at a reference position for X-ray imaging;
X-ray imaging means for receiving X-rays transmitted through the subject;
Swivel drive means for rotating an arm that holds the X-ray source and the X-ray imaging means at a predetermined interval so that the subject can be held around a predetermined rotation center;
Frame storage means for storing a plurality of frame images which are X-ray imaging results of the subject at a standard tomographic position predetermined in the apparatus corresponding to the positioning of the subject to the reference position;
Panoramic image processing means for generating a panoramic tomographic image of a specified tomographic position;
An X-ray imaging apparatus having display means for displaying the panoramic tomographic image,
The impression of the subject collected by the impression material attached to the positioning aid for copying the type of the subject is aligned with the standard photographing trajectory indicating the standard tomographic position viewed from the rotation axis direction of the turning drive means. A camera-captured image storage means for storing a camera-captured image captured by the camera,
The panoramic image processing means superimposes the trajectory of the tomographic position of the subject viewed from the rotation axis direction of the turning drive means on the camera image and outputs it to the display means. The panoramic tomography is received by receiving selection and deformation instructions, obtaining an overlap width of the plurality of frame images based on information of the selected and deformed trajectories, and reconstructing the tomographic images of the selected and deformed trajectories An X-ray imaging apparatus characterized by generating an image. Based on the information on the selected and deformed trajectory, the subject is selected and deformed at the position of the deformed trajectory according to the deviation of the selected and deformed trajectory position from the standard tomographic position. Image size correction means for correcting to an image size corresponding to the image size assumed when there is no shift by enlarging or reducing the configured tomographic image,
The X-ray imaging apparatus according to claim 1, wherein the display unit displays the tomographic image with the image size corrected as the panoramic tomographic image.   The X-ray imaging apparatus according to claim 1, wherein the arm is provided with the camera aligned with the reference position for the X-ray imaging and the standard imaging trajectory. In order to generate a panoramic tomographic image of the specified tomographic position of the subject,
Frame image storage means for storing a plurality of frame images acquired by panoramic imaging of a tomographic image of a subject by an X-ray imaging apparatus;
Stores a camera-captured image taken by the camera by aligning the impression of the subject collected by an impression material attached to a positioning aid to copy the subject's mold with the standard imaging trajectory of the X-ray imaging apparatus. A computer equipped with camera-captured image storage means for
Drawing means for drawing a trajectory of the tomographic position of the subject;
A synthesizing unit that synthesizes the trajectory of the tomographic position of the drawn subject and the camera image and outputs the synthesized image to the display unit;
Change accepting means for accepting selection and deformation instructions for the trajectory of the displayed fault position and instructing the drawing means to draw the selected and deformed trajectory;
Image reconstructing means for obtaining an overlap width of the plurality of frame images based on the selected and deformed trajectory information, and reconstructing a tomographic image of the selected and deformed trajectory;
An image processing program for panorama characterized in that it functions as

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