JP5459651B2 - X-ray imaging apparatus, inspection / maintenance time notification method and apparatus - Google Patents

Description

  The present invention performs imaging while continuously rotating an X-ray source and an X-ray detector around a subject such as a human body, and subtracks a mask image and a contrast image to obtain a blood vessel image of the subject. The present invention relates to an inspection / maintenance time notification method and apparatus for informing an inspection / maintenance time of the X-ray imaging apparatus.

  For example, R-DAS (rotation-digital subtrackion angiography) and 3D-Angio (three-dimensional angio) examinations are performed as examination applications for grasping complex blood vessel structures of a subject such as a human body as a patient. ing. In imaging techniques such as blood vessel structure in these examinations, an X-ray imaging apparatus including a C-arm holding device that rotatably holds a C-arm provided with an X-ray source and an X-ray detector is used.

  In imaging of blood vessel structure and the like, for example, as shown in FIG. 7, the X-ray source 1 and the X-ray detector 2 are reciprocally rotated around the subject 3 at a high speed by rotating the C arm, for example, continuously at every angle φ. Photographing is performed, a mask image and a contrast image at the same angular position within a predetermined rotation angle range θ of the X-ray source 1 and the X-ray detector 2 are acquired, and two captured images of the mask image and the contrast image are acquired. To extract the blood vessel image of the subject 3.

  In the process of extracting the blood vessel image of the subject 3 from the two photographed images, if there is a deviation of the photographing position between the mask image and the contrast image, it appears as a misregistration in the subtracked image, and the subtracked image Becomes difficult to see and appears as a false image when a three-dimensional image is reconstructed based on a plurality of mask images and a plurality of contrast images, so that accurate photographing information cannot be provided.

The misalignment that causes misregistration is caused by the vibration of the X-ray imaging apparatus itself accompanying the rigidity of the building such as the examination room where the X-ray imaging apparatus is installed, the C arm holding the C arm, etc. This occurs due to the rigidity (vibration resistance) of the device, looseness generated in the fastening portion thereof, and the like, and the looseness caused by long-term use of the mechanical structure portion in the C-arm holding device, that is, aging.
Such a misregistration value gradually increases with long-term use of the X-ray imaging apparatus. Imaging of blood vessel structures and the like using an X-ray imaging apparatus is performed every day, leading to deterioration of clinical sub-tracked images acquired by imaging. For example, the image quality of the sub-trackion image acquired at the beginning of installation of the X-ray imaging apparatus is good, but the image quality of the sub-trackion image acquired using the X-ray imaging apparatus for a long period of time is deteriorated. For this reason, deterioration of the sub-tracked image is often pointed out by the user side of the X-ray imaging apparatus. However, since the X-ray imaging apparatus does not have a function for constantly monitoring the misregistration value, there is no way to know the increase in the misregistration value.

  An object of the present invention is to provide an X-ray imaging apparatus capable of detecting a misregistration amount between a mask image and a contrast image, and informing that when it is time for inspection / maintenance, an inspection / maintenance time notification method, and an apparatus therefor. There is.

The X-ray imaging apparatus according to claim 1 of the present invention performs imaging while continuously rotating the X-ray source and the X-ray detector around the subject, and the X-ray source and the X-ray detector are the same. In an X-ray imaging apparatus that extracts a blood vessel image of a subject by subtracking a mask image and a contrast image within a rotation angle range, an X-ray source and an X-ray source at the initial use of the apparatus and after the initial use The amount of positional deviation between the mask image and the contrast image at the same angular position within the rotational angle range acquired by continuous imaging with the line detector is detected, and the position is detected each time this positional deviation is detected. When the statistical value acquired by this statistical processing exceeds a threshold, statistical processing is performed on the positional deviation amount storage unit that stores and accumulates the positional deviation amount, and a plurality of positional deviation amounts accumulated by the positional deviation amount storage unit. Inspection and maintenance are necessary It includes a statistical processing and notifying unit for notifying the fact that.

According to a sixth aspect of the present invention, an inspection / maintenance time notification method for notifying an inspection / maintenance time of an X-ray imaging apparatus comprises the X-ray imaging apparatus at the initial use of the X-ray imaging apparatus and after the initial use. The amount of misalignment between the mask image and the contrast image at the same angular position acquired when the X-ray source and the X-ray detector are continuously rotated is detected. The amount of misregistration is stored and stored in the memory by computer processing, and a plurality of misregistration amounts accumulated in the memory by computer processing are statistically processed. The statistical value obtained by this statistical processing has a threshold value. If it exceeds, a notification device informs that inspection / maintenance of the X-ray imaging apparatus is necessary.

An inspection / maintenance time notification device for notifying an inspection / maintenance time of an X-ray imaging apparatus according to claim 7 of the present invention constitutes the X-ray imaging apparatus at the initial use of the X-ray imaging apparatus and after the initial use. The amount of misalignment between the mask image and the contrast image at the same angular position acquired when the X-ray source and the X-ray detector are continuously rotated is detected. The misregistration amount storage unit that stores and accumulates misregistration amounts, and the plurality of misregistration amounts accumulated by the misregistration amount storage unit are statistically processed, and the statistical value acquired by this statistical processing has a threshold value. If exceeding, a statistical processing / notification unit for notifying from the alarm device that the inspection / maintenance of the X-ray imaging apparatus is necessary is provided.

  According to the present invention, it is possible to provide an X-ray imaging apparatus, an inspection / maintenance time notification method, and an apparatus for detecting the misregistration amount between a mask image and a contrast image and informing the detection / maintenance time. .

Hereinafter, an embodiment of the present invention will be described with reference to the drawings. In addition, the same code | symbol is attached | subjected to the same part as FIG.
FIG. 1 shows a configuration diagram of an X-ray imaging apparatus. This X-ray imaging apparatus has an inspection / maintenance time notification function. The X-ray source 1 and the X-ray detector 2 are provided at each end of the C arm 10. The C arm 10 is reciprocally rotated around the subject 3 at a high speed by the rotation mechanism 11 via a C arm holding device or the like that holds the C arm 10. The X-ray source 1 and the X-ray detector 2 rotate reciprocally within a predetermined rotation angle range θ, for example.

  The arithmetic processing unit 20 is composed of a computer and has a main control unit 21 having a CPU and the like. A mask image memory 22, a contrast image memory 23, and a subtraction image memory 24 are connected to the main control unit 21, and a C arm control unit 25 that operates according to a command issued from the main control unit 21, and an image processing unit 26, a misregistration amount storage unit 27, and a statistical processing / notification unit 28.

The C-arm control unit 25 controls the rotation mechanism 11 to rotate the X-ray source 1 and the X-ray detector 2 back and forth around the subject 3 at a high speed, for example, within a predetermined rotation angle range θ.
The image processing unit 26 detects the X-ray source 1 and the X-ray detector 1 when the X-ray source 1 and the X-ray detector 2 are reciprocatingly rotated around the subject 3 at a high speed, for example, within a predetermined rotation angle range θ. Each time the device 2 rotates to a predetermined angle, for example, an angle φ, an image is taken and the output signal of the X-ray detector 2 is inputted, and each mask image M as shown in FIG. Saved in the mask image memory 22. The mask image M is stored in the mask image memory 22 at the initial stage of use of the present apparatus, for example, immediately after the installation of the apparatus and every imaging of the angiographic examination on the subject 3 after the installation of the apparatus. As a result, the mask image memory 22 stores a plurality of mask images for each angle φ during each imaging of the subject 3 performed at the time of installation of the apparatus and thereafter, and for each angle φ during one imaging of the subject 3. Is saved.

  Further, the image processing unit 26 moves the X-ray source 1 and the X-ray detector 2 around the subject 3 within, for example, a predetermined rotation angle range θ in a state in which a contrast medium is injected into the subject 3 by angiography. When the X-ray source 1 and the X-ray detector 2 rotate at a predetermined angle, for example, an angle φ, when the reciprocating rotation is performed at high speed, an image is taken and the output signal of the X-ray detector 2 is input. For example, a contrast image C as shown in FIG. 2 is created for each φ and stored in the contrast image memory 23. The storage of the contrast image C in the contrast image memory 23 is performed at the time of installation of the apparatus of the present apparatus and every subsequent imaging of the angiography examination on the subject 3 in the same manner as the storage of the mask image M. Thereby, the contrast image memory 23 stores, for example, a plurality of contrast images for each angle φ during each imaging of the subject 3 performed at the time of installation of the apparatus and thereafter and for each angle φ during one imaging of the subject 3. C is saved.

  Further, the image processing unit 26 reads out, for example, a mask image M as shown in FIG. 2 stored in the mask image memory 22, and the X-ray source 1 and the X-ray detector 2 that have photographed the mask image M. If the shooting angle is the same as the shooting angle, for example, the shooting angle when the mask image M is shot is φn, the contrast image C acquired when angiography is shot at the same shooting angle φn from the contrast image memory 23. A sub-tracking image S is generated by extracting the blood vessel image of the subject 3 by performing sub-tracking of the read mask image M and the contrast image C, and the sub-tracking image S is sub-tracked. Save in the image memory 24.

Here, as shown in FIG. 3, for example, the mask image at the photographing angle φn acquired immediately after the installation of the apparatus is set as M1, and the contrast of the imaging angle φn acquired at the shooting immediately after the installation of the apparatus is set as C1. To do. Further, for example, each mask image at the photographing angle φn acquired for each photographing after the installation of the apparatus is set to M2 to Mm, and the contrast of the photographing angle φn obtained by the photographing at the time of installing the apparatus is set to C2 to Cm. And As a result, the mask image memory 22 stores, for example, each mask image M1 for each angle of the subject 3 taken immediately after the apparatus is installed and thereafter, and for each angle φ during a single photographing of the subject 3. ~ Mm is saved. Similarly, the contrast image memory 23 stores, for example, a plurality of contrast images for each angle of the subject 3 taken immediately after the installation of the apparatus and thereafter, and for each angle φ during a single photographing of the subject 3. C1 to Cm are stored.

The misregistration amount storage unit 27 is, for example, each mask image at an imaging angle φn obtained by imaging during continuous rotation of the X-ray source 1 and the X-ray detector 2 immediately after the apparatus installation and after the apparatus installation, for example. Each misregistration amount, that is, a misregistration amount between M1 to Mm and each of the contrast images C1 to Cm is detected and stored and stored every time this misregistration amount is detected . Specifically, the misregistration detection unit 27a And a misalignment memory 27b.

The misregistration detection unit 27a reads out the mask images M1,..., Mm stored in the mask image memory 22 and captures the contrast stored in the contrast image memory 23, for example, immediately after the apparatus installation and every time after the apparatus installation. image C1, ..., reads Cm, these mask images M1, ..., Mm and contrast image C1, ..., detects each misregistration amount of the X and Y directions between the Cm, respectively. The positional shift detection unit 27a, for example the mask image M1 by the auto-pixel shift function, ..., Mm and contrast image C1, ..., detects each misregistration amount in pixels between Cm, respectively. Specifically, the misregistration detection unit 27a sets ROIs (regions of interest) in the same area of the mask image M1 and the contrast image C1, for example, and the mask image M1 and the contrast image C1 in pixel units by the auto pixel shift function in these ROIs. The misregistration amounts in the X direction and the Y direction are respectively detected. The misregistration detection unit 27a stores and accumulates each misregistration amount sequentially detected in the misregistration memory 27b, for example, immediately after the apparatus installation and after the apparatus installation.

  The statistical processing / notification unit 28 statistically processes a plurality of misregistration amounts accumulated in the positional deviation memory 27b of the positional deviation amount storage unit 27, and a statistical value acquired by the statistical processing exceeds a threshold value. And that the inspection / maintenance is necessary, and specifically includes a statistical processing unit 28a and a notification unit 28b.

Statistical processing section 28a, a plurality of misregistration amount, for example, mask images M1, ..., Mm and contrast image C1, ..., and statistically processing the X-direction, the misregistration amount in the Y direction between the Cm example The frequency distributions F1 and F2 in the X direction and the Y direction as shown in FIGS. 4 and 5 are obtained. The statistical processing unit 28a calculates a statistical value, for example, a maximum value, an average value, a standard deviation value, a variance value, or a median value from each of the frequency distributions F1 and F2, and these maximum value, average value, standard deviation value, variance If any one of the value and the median value exceeds a preset threshold value, it is determined that inspection / maintenance is required for at least the structural portion including the C arm 10 and the rotation mechanism 11, and the notification portion 28. A command is issued to notify that the inspection / maintenance is necessary.

Here, the threshold value is, for example, each maximum value, each average value, each standard deviation value, each variance value, or each median value calculated from each frequency distribution F ₁ , F _{2 in} each of the X direction and the Y direction. Is set to Thereby, the statistical processing unit 28a has a threshold in which any one of the maximum value, each average value, each standard deviation value, each variance value, or each median value is preset in the X direction or the Y direction. When the value is exceeded, a command for notifying the notification unit 28 that it is time to inspect and maintain is issued.

  The notification unit 28 is composed of a display, an alarm device, etc., and receives an inspection / maintenance notification command issued from the statistical processing unit 28a to display on the display screen that it is a time when inspection / maintenance is necessary. And, an alarm is sounded to sound an alarm indicating that it is time to inspect and maintain. Further, when the notifying unit 28 receives the inspection / maintenance notification command issued from the statistical processing unit 28a, the notifying unit 28 informs the service center that inspects / maintains the apparatus that the inspection / maintenance is necessary. Notify via

Next, the inspection / maintenance time notification operation in the apparatus configured as described above will be described with reference to the inspection / maintenance time notification operation flowchart shown in FIG.
The apparatus is installed in a hospital building, for example. For example, immediately after the installation of the apparatus is completed, an initial misregistration amount is obtained, for example, when an angiographic examination is performed on the subject 3 for the first time for the apparatus.
First, in a state in which no contrast agent is injected into the subject 3, the main control unit 21 issues a drive command to the C arm control unit 25 in step # 1 and X-ray emission command is issued. As a result, the C arm control unit 25 drives the rotation mechanism 11 to rotate the C arm 10. The rotation of the C arm 10 causes the X-ray source 1 and the X-ray detector 2 to reciprocate at high speed around the subject 3 within a predetermined rotation angle range θ, for example. At this time, imaging of the subject 3 is performed every time the X-ray source 1 and the X-ray detector 2 rotate by a predetermined angle, for example, an angle φ. That is, every time the X-ray source 1 and the X-ray detector 2 rotate, for example, by an angle φ, the X-ray source 1 emits X-rays. This X-ray passes through the subject 3 and enters the X-ray detector 2. The X-ray detector 2 outputs a signal corresponding to the incident X-ray dose.

The image processing unit 26 inputs an output signal of the X-ray detector 2 every time the X-ray source 1 and the X-ray detector 2 rotate to an angle φ, for example, and a mask as shown in FIG. An image M is created and stored in the mask image memory 22. For example, when the apparatus is installed, if the mask image M acquired at the photographing angle φn is, for example, the mask image M ₁ shown in FIG. 3, the image processing unit 26 stores the mask image M ₁ in the mask image memory 22. To do. Note that the image processing unit 26 also stores each mask image M acquired at another photographing angle φn in the mask image memory 22.

  Next, in a state in which the contrast medium is injected into the subject 3, the main control unit 21 issues a drive command to the C-arm control unit 25 and X-ray emission command to the X-ray source 1. To emit. As a result, the C arm control unit 25 drives the rotation mechanism 11 to rotate the C arm 10. The rotation of the C arm 10 causes the X-ray source 1 and the X-ray detector 2 to reciprocate at high speed around the subject 3 within a predetermined rotation angle range θ, for example. At this time, imaging of the subject 3 is performed every time the X-ray source 1 and the X-ray detector 2 rotate by a predetermined angle, for example, an angle φ. That is, every time the X-ray source 1 and the X-ray detector 2 rotate, for example, by an angle φ, the X-ray source 1 emits X-rays. This X-ray passes through the subject 3 and enters the X-ray detector 2. The X-ray detector 2 outputs a signal corresponding to the incident X-ray dose.

The image processing unit 26 inputs an output signal of the X-ray detector 2 every time the X-ray source 1 and the X-ray detector 2 rotate to an angle φ, for example, and a mask as shown in FIG. An image M is created and stored in the mask image memory 22. For example, when the apparatus is installed, if the contrast image C acquired at the shooting angle φn is, for example, the contrast image C ₁ shown in FIG. 3, the image processing unit 26 stores the contrast image C ₁ in the contrast image memory 23. To do. Note that the image processing unit 26 also saves each contrast image C acquired at another shooting angle φn in the contrast image memory 23.

In order to perform an angiographic examination on the subject 3, the image processing unit 26 reads out the mask image M ₁ stored in the mask image memory 22, and the X-ray source 1 that images the mask image M _1. If the imaging angle is the same as the imaging angle with the X-ray detector 2, for example, the imaging angle when the mask image M is imaged, the contrast image acquired when angiography is performed at the same imaging angle φn. reads the C ₁ from the contrast image memory 23 to create a sub track Deployment image S which performs sub-tracks Deployment extracted blood vessel image of the subject 3 with the mask image M ₁ and the contrast image C ₁ that these read, The sub-trackion image S is stored in the sub-trackion image memory 24. This sub-trackion image S is displayed on a display (not shown), for example.

Then, positional deviation amount storage unit 27, misregistration amount in step # 2, a mask image M ₁ and contrast image C ₁ in which has been for example imaging angle φn obtained by first angiography immediately after example device installation Is detected. That is, the position shift detecting unit 27a, for example reads the mask image M ₁ stored in the mask image memory 22 in device installation immediately after capture, reads the contrast image C ₁ stored in the contrast image memory 23, these mask image Each misregistration amount in the X direction and the Y direction between M ₁ and the contrast image C ₁ is detected in units of pixels, for example, by an auto pixel shift function. Specifically positional shift detection unit 27a, for example to set the ROI (region of interest) in the same area of the mask image M ₁ and the contrast image C _1, a mask image M ₁ in pixels by the auto-pixel shift function in these ROI detecting each misregistration amount of the X and Y directions of the contrast image C _1, respectively.

Then, positional deviation amount storage unit 27, steps in # 3, for example, devices each miss the X and Y directions of the installation and the mask image M ₁ obtained by the first angiography immediately after the contrast image C ₁ Each registration amount is stored in the misregistration memory 27b. Thereby, the misregistration amount immediately after the installation of the apparatus is stored in the misalignment memory 27b.

  Next, in step # 4, the main controller 21 determines whether or not the current angiographic examination is the first angiographic examination. Since the current angiographic examination is the first angiographic examination, the main control unit 21 returns to step # 2 and waits until the next angiographic examination.

  Next, when the second angiographic examination of the subject 3 is performed for the present apparatus, the X-ray source 1 and the X-ray source 1 are set in the state where the contrast medium is not injected into the subject 3 as described above. The line detector 2 reciprocally rotates around the subject 3 at a high speed, for example, within a predetermined rotation angle range θ. At this time, imaging of the subject 3 is performed every time the X-ray source 1 and the X-ray detector 2 rotate, for example, by an angle φ. The subject 3 may be the same patient as the subject 3 in the second angiography examination or may be a different patient.

The image processing unit 26 inputs an output signal of the X-ray detector 2 every time the X-ray source 1 and the X-ray detector 2 rotate to an angle φ, for example, and is obtained at an imaging angle φn, for example, as shown in FIG. Such a mask image M ₁ is created and stored in the mask image memory 22. Note that the image processing unit 26 also stores each mask image M acquired at another photographing angle φn in the mask image memory 22.

Next, the X-ray source 1 and the X-ray detector 2 are reciprocally rotated around the subject 3 at a high speed, for example, within a predetermined rotation angle range θ in a state where the contrast agent is injected into the subject 3. At this time, imaging of the subject 3 is performed every time the X-ray source 1 and the X-ray detector 2 rotate, for example, by an angle φ.
The image processing unit 26 inputs an output signal of the X-ray detector 2 every time the X-ray source 1 and the X-ray detector 2 rotate to an angle φ, for example, and is obtained at an imaging angle φn, for example, as shown in FIG. Such a contrast image C ₂ is created and stored in the contrast image memory 23. Note that the image processing unit 26 also saves the respective contrast images C acquired at other shooting angles φn in the mask image memory 22.
In order to perform angiography to the subject 3, the image processing unit 26, in the same manner as described above to extract the blood vessel image of the subject 3 by performing the sub-tracks Deployment of the mask image M ₂ and contrast image C ₂ A sub-trackion image S is created, and the sub-trackion image S is stored in the sub-trackion image memory 24 and displayed on the display.

Then, positional deviation amount storage unit 27, Step # 2 the example second time misregistration amount detection of the mask image M ₂ and contrast image C ₂ in which the obtained e.g. imaging angle φn by angiography To do. That is, the position shift detecting unit 27a, for example reads the mask image M ₂ stored in the mask image memory 22 in photographing in the second round of angiography, a contrast image C ₂ stored in the contrast image memory 23 reading, to set the ROI (region of interest) in the same area of these mask image M ₂ and contrast image C _2, X direction between the mask image M ₂ and contrast image C ₂ in pixels by the auto-pixel shift function in these ROI And misregistration amounts in the Y direction are detected.

Then, positional deviation amount storage unit 27, in step # 3, for example, the misregistration between the X and Y directions of the mask image M ₂ and contrast image C ₂ obtained by the second round of angiography Each amount is stored in the misregistration memory 27b.

Next, as a result of determining whether or not the current angiography examination is the first angiography examination in Step # 4, the main control section 21 is the second angiography examination. Therefore, the process proceeds to step # 5, and statistical processing of the misregistration amount stored in the misregistration memory 27b is performed. That is, the statistical processing unit 28a stores a plurality of misregistration amounts stored in the misregistration memory 27b, for example, misregistration in the X direction and the Y direction between the mask images M1 and M2 and the contrast images C1 and C2 . The amount is statistically processed to obtain frequency distributions F1 and F2 for each of the X and Y directions as shown in FIGS. 4 and 5, for example.

Next, the statistical processing unit 28a calculates a statistical value, for example, a maximum value, an average value, a standard deviation value, a variance value, or a median value from each of the frequency distributions F ₁ and F ₂ , and these maximum value, average value, and standard value It is determined whether any one of the deviation value, the variance value, or the median value exceeds a preset threshold value. Here, the misregistration amounts in the X direction and Y direction acquired at the first and second angiographic examinations immediately after installation of the present apparatus are only stored in the misalignment memory 27b. Therefore, any _{one of} the statistical values of the frequency distributions F ₁ and F ₂ , for example, the maximum value, the average value, the standard deviation value, the variance value, or the median value does not exceed a preset threshold value. . Note that the threshold value is, for example, for each maximum value, each average value, each standard deviation value, each variance value, or each median value calculated from each frequency distribution F ₁ , F _{2 in} each of the X direction and the Y direction. Is set. Therefore, the main control unit 21 returns to step # 2 and waits for the next angiographic examination.

Thereafter, when the m-th angiographic examination of the subject 3 is performed for the present apparatus, the X-ray source 1 and the X-ray source 1 in the state where the contrast medium is not injected into the subject 3 as described above. The line detector 2 reciprocally rotates around the subject 3 at a high speed, for example, within a predetermined rotation angle range θ. At this time, imaging of the subject 3 is performed every time the X-ray source 1 and the X-ray detector 2 rotate, for example, by an angle φ.
The image processing unit 26 inputs an output signal of the X-ray detector 2 every time the X-ray source 1 and the X-ray detector 2 rotate to an angle φ, for example, and is obtained at an imaging angle φn, for example, as shown in FIG. Such a mask image Mm is created and stored in the mask image memory 22. Note that the image processing unit 26 also stores each mask image M acquired at another photographing angle φn in the mask image memory 22.

Next, the X-ray source 1 and the X-ray detector 2 are reciprocally rotated around the subject 3 at a high speed, for example, within a predetermined rotation angle range θ in a state where the contrast agent is injected into the subject 3. At this time, imaging of the subject 3 is performed every time the X-ray source 1 and the X-ray detector 2 rotate, for example, by an angle φ.
The image processing unit 26 inputs an output signal of the X-ray detector 2 every time the X-ray source 1 and the X-ray detector 2 rotate to an angle φ, for example, and is obtained at an imaging angle φn, for example, as shown in FIG. Such a contrast image Cm is created and stored in the contrast image memory 23. Note that the image processing unit 26 also saves the respective contrast images C acquired at other shooting angles φn in the mask image memory 22.

  Next, in step # 2, the misregistration amount storage unit 27 detects a misregistration amount between the mask image Mm and the contrast image Cm, for example, at the imaging angle φn acquired by the m-th angiography examination, for example. That is, the misregistration detection unit 27a reads out the mask image Mm stored in the mask image memory 22 in, for example, imaging in the m-th angiography examination, and reads out the contrast image Cm stored in the contrast image memory 23. An ROI (region of interest) is set in the same area between the mask image Mm and the contrast image Cm, and the X and Y directions of the mask image Mm and the contrast image Cm are set pixel by pixel by the auto pixel shift function in these ROIs. Each misregistration amount is detected.

  Next, in step # 3, the misregistration amount storage unit 27 calculates the misregistration amounts in the X direction and the Y direction between the mask image Mm and the contrast image Cm acquired by, for example, the m-th angiography examination. Each is stored in the misregistration memory 27b.

Next, since the current angiographic examination is the m-th angiographic examination in step # 4, the main control unit 21 moves to step # 5 and the misregistration amount stored in the misregistration memory 27b. Perform statistical processing. That is, the statistical processing unit 28a has a plurality of misregistration amounts stored in the misregistration memory 27b, for example, errors in the X direction and the Y direction between the mask images M1 to Mm and the contrast images C1 to Cm. The registration amount is statistically processed to obtain frequency distributions F1 and F2 for each of the X direction and the Y direction as shown in FIGS. 4 and 5, for example.

Next, in step # 6, the statistical processing unit 28a calculates a statistical value, for example, a maximum value, an average value, a standard deviation value, a variance value, or a median value from each of the frequency distributions F ₁ and F ₂ , and these maximum values It is determined whether any one of the average value, the standard deviation value, the variance value, or the median value exceeds a preset threshold value.
As a result of this determination, if any _{one of} the statistical values calculated from the frequency distributions F ₁ and F ₂ , for example, any one of the maximum value, average value, standard deviation value, variance value, or median value exceeds a preset threshold value. The statistical processing unit 28a determines that inspection / maintenance is required for at least the structural unit including the C arm 10 and the rotation mechanism 11 and the notification unit 28 needs inspection / maintenance. A command for informing is issued.

  In step # 7, the notification unit 28 receives an inspection / maintenance notification command issued from the statistical processing unit 28a, displays on the display screen that it is necessary to perform inspection / maintenance, and displays an alarm. Sound an alarm to remind you that it is time to inspect and maintain. Further, when the notifying unit 28 receives the inspection / maintenance notification command issued from the statistical processing unit 28a, the notifying unit 28 informs the service center that inspects / maintains the apparatus that the inspection / maintenance is necessary. Notify via As a result, the service person who has received the inspection / maintenance time at the service center performs the inspection / maintenance of the apparatus.

Thus, according to the above-described embodiment, the same angular position acquired when the X-ray source 1 and the X-ray detector 2 are continuously rotated immediately after the installation of the apparatus and thereafter, for example, For example, the misregistration amount between the mask image M and the contrast image C at the photographing angle φn is detected , stored and stored in the misregistration memory 27b each time this detection is performed, and the misregistration accumulated in the misregistration memory 27b. The quantity is statistically processed, and when the statistical value acquired by this statistical process exceeds a threshold value, it is notified that it is time to inspect and maintain the apparatus.

  This makes it possible to inspect and maintain the apparatus before the misregistration amount of the apparatus increases and the image quality of the sub-trackation image S is significantly deteriorated. That is, an imaging position shift that causes misregistration causes vibration of the X-ray imaging apparatus itself of the apparatus accompanying the rigidity of a building such as an examination room in which the X-ray imaging apparatus is installed, C arm holding the C arm, and the like. This occurs due to the rigidity (vibration resistance) of the arm holding device, the backlash generated in the fastening portion thereof, and the backlash generated due to long-term use of the mechanical structure portion in the C arm holding device, that is, the secular change. Thus, it is possible to inspect and maintain the apparatus before the deterioration of the image quality of the sub-trackation image S due to the increase in the misregistration amount caused by the play caused by the secular change or the like becomes significant. .

In addition, since an abnormality or the like occurring in the apparatus can be predicted from the misregistration amount of the apparatus, it is possible to prevent and maintain an abnormality in the apparatus. Further, since each misregistration amount in the X direction and the Y direction is separately statistically processed, it is possible to easily identify the location where an abnormality occurs in the apparatus.
Further, since the misregistration amount is statistically processed, for example, even when the subject 3 such as a patient moves, it is detected that the misregistration has occurred in the X direction or the Y direction, but when the subject 3 moves. 4 and 5 appear as singular points on the frequency distributions F ₁ and F ₂ as shown in FIGS. 4 and 5, for example, in a laboratory where the X-ray imaging apparatus is installed even if the subject 3 moves. Originally generated due to vibration of the X-ray imaging apparatus itself accompanying the rigidity of the building, the rigidity (vibration resistance) of the C-arm holding device that holds the C-arm, etc., and looseness caused by secular change of the fastening portion, etc. The increase in misregistration amount is not affected.

  As a result, it is possible to prevent deterioration of the image quality of the sub-trackation image S due to an increase in misregistration amount in advance, and to accurately grasp the inspection / maintenance time required for the apparatus until the apparatus goes down. The period can be extended.

  However, for example, R-DAS and 3D-Angio tests are performed as test applications for grasping complicated blood vessel structures of a subject such as a human body as a patient, and these R-DAS and 3D-Angio tests are performed. Therefore, if this device is applied, before the image quality of images acquired by R-DAS or 3D-Angio inspection deteriorates, inspection and maintenance can be performed on this device, and abnormalities occurring in this device can be detected. Foreseeing can prevent and maintain the occurrence of abnormalities, and can easily identify the locations where abnormalities occur.

Note that the present invention is not limited to the above-described embodiment as it is, and can be embodied by modifying the constituent elements without departing from the scope of the invention in the implementation stage. In addition, various inventions can be formed by appropriately combining a plurality of components disclosed in the embodiment. For example, some components may be deleted from all the components shown in the embodiment. Furthermore, constituent elements over different embodiments may be appropriately combined.
For example, the misregistration amount storage unit 27 and the statistical processing / notification unit 28 are unitized and not limited to a built-in configuration for performing R-DAS or 3D-Angio inspection, but are attached to and detached from the X-ray imaging apparatus. Possible configurations are also possible.
With such a configuration, the positional deviation amount storage unit 27 and the statistical processing / notification unit 28 that are unitized with respect to the existing X-ray imaging apparatus are attached to the X-ray source 1 in the existing X-ray imaging apparatus. A misregistration amount between the mask image M and the contrast image C at the same angular position acquired when the X-ray detector 2 is continuously rotated, for example, the imaging angle φn, for example, is detected. The misregistration amount stored in and stored in the shift memory 27b is statistically processed, and if the statistical value obtained by the statistical processing exceeds a threshold value, the apparatus is inspected.・ Can notify that maintenance is necessary. The detection of the misregistration amount of the existing X-ray imaging apparatus is started only after the unitized misregistration amount storage unit 27 and the statistical processing / notification unit 28 are attached to the existing X-ray imaging apparatus. It may be from an angiographic examination of specimen 3.

1 is a configuration diagram showing an embodiment of an X-ray imaging apparatus according to the present invention. The figure which shows the subtrackion image produced from the mask image and the contrast image by the same apparatus. The figure which shows the mask image and contrast image which are acquired by the apparatus at the time of apparatus installation and after that. The figure which shows the frequency distribution of the X direction calculated | required by the statistical processing part in the apparatus. The figure which shows the frequency distribution of the Y direction calculated | required by the statistical processing part in the apparatus. The operation | movement alerting | reporting operation | movement time of inspection and maintenance in the same apparatus. The figure which shows the acquisition method of the subtrackion image in an angiography examination.

Explanation of symbols

  1: X-ray source, 2: X-ray detector, 3: Subject, 10: C arm, 11: Rotating mechanism, 20: Arithmetic processing device, 21: Main control unit, 22: Mask image memory, 23: Contrast image Memory, 24: subtraction image memory, 25: C-arm control unit, 26: image processing unit, 27: misregistration amount storage unit, 28: statistical processing / notification unit, 27a: misregistration detection unit, 27b: misregistration memory, 28a: Statistical processing unit, 28b: Notification unit.

Claims (11)

Imaging is performed while continuously rotating the X-ray source and the X-ray detector around the subject, and a mask image and a contrast image within the same rotation angle range of the X-ray source and the X-ray detector are obtained. In an X-ray imaging apparatus that extracts a blood vessel image of the subject by subtracking,
The mask image at the same angular position within the rotation angle range acquired by imaging during continuous rotation of the X-ray source and the X-ray detector at the initial use of the apparatus and after the initial use. A positional deviation amount storage unit that detects the positional deviation amount between the image and the contrast image and stores and accumulates the positional deviation amount each time the positional deviation amount is detected ;
A statistical processing is performed on the plurality of positional deviation amounts accumulated by the positional deviation amount storage unit, and if the statistical value acquired by the statistical processing exceeds a threshold value, it indicates that inspection / maintenance is necessary. A statistical processing / notification unit for reporting;
An X-ray imaging apparatus comprising: The positional deviation amount storage unit detects the positional deviation amount in an X direction and a Y direction between the mask image and the contrast image, and
A misregistration memory for storing the misregistration amount detected by the misregistration detection unit;
The X-ray imaging apparatus according to claim 1, further comprising:   The X-ray imaging apparatus according to claim 2, wherein the misregistration detection unit detects the misregistration amount in a pixel unit size. The statistical processing and notifying unit, said plurality of positional deviation amount statistical processing to determine the frequency distribution of the positional deviation amount, at least the maximum value as the statistical value obtained from the frequency distribution, mean, standard deviation The X-ray imaging apparatus according to claim 1, wherein when any one of a variance value or a median value exceeds the threshold value, the fact that the inspection / maintenance is necessary is notified. A C-arm that holds the X-ray source and the X-ray detector, and continuously rotates the X-ray source and the X-ray detector around the subject ;
A rotation mechanism for rotatably holding the C-arm;
With
When the statistical value acquired by the statistical processing exceeds the threshold value, the statistical processing / notification unit needs to inspect and maintain at least the structural unit including the C arm and the rotation mechanism. To inform you of this,
The X-ray imaging apparatus according to claim 1. In the inspection / maintenance time notification method for informing the inspection / maintenance time of the X-ray imaging apparatus,
At the same angular position acquired when the X-ray source and the X-ray detector constituting the X-ray imaging apparatus are continuously rotated during the initial use of the X-ray imaging apparatus and after the initial use. The amount of misalignment between the mask image and the contrast image is detected, and each time this misalignment amount is detected, the misregistration amount is stored in a memory by a computer process and accumulated.
When a plurality of the positional deviation amounts accumulated in the memory are statistically processed by the processing of the computer, and a statistical value acquired by the statistical processing exceeds a threshold value, inspection / maintenance for the X-ray imaging apparatus is performed. Notifying from the alarm device that it is necessary,
An inspection / maintenance time notification method characterized by that. In the inspection / maintenance time notification device for informing the inspection / maintenance time of the X-ray imaging device,
At the same angular position acquired when the X-ray source and the X-ray detector constituting the X-ray imaging apparatus are continuously rotated during the initial use of the X-ray imaging apparatus and after the initial use. A misregistration amount storage unit that detects the misregistration amount between the mask image and the contrast image, and stores and accumulates the misregistration amount each time the misregistration amount is detected ;
Statistical processing is performed on the plurality of positional deviation amounts accumulated by the positional deviation amount storage unit, and if the statistical value acquired by the statistical processing exceeds a threshold value, inspection / maintenance of the X-ray imaging apparatus is required. A statistical processing / notification unit that informs the fact that it is,
An inspection / maintenance time notification device characterized by comprising: The positional deviation amount storage unit detects the positional deviation amount in an X direction and a Y direction between the mask image and the contrast image, and
A misregistration memory for storing the misregistration amount detected by the misregistration detection unit;
The inspection / maintenance time notification device according to claim 7, wherein:   The inspection / maintenance time notification device according to claim 8, wherein the misregistration detection unit detects the misregistration amount in a pixel unit size.   The statistical processing / notification unit obtains a frequency distribution of the positional deviation amounts by statistically processing the plurality of positional deviation amounts, and at least a maximum value, an average value, and a standard deviation as the statistical values acquired from the apparent frequency distribution 8. The inspection / maintenance time notification device according to claim 7, wherein when any one of a value, a variance value, or a median value exceeds the threshold value, the fact that the inspection / maintenance is necessary is notified. . A C-arm that holds the X-ray source and the X-ray detector and continuously rotates the X-ray source and the X-ray detector around a subject ;
A holding mechanism for rotatably holding the C-arm;
With
When the statistical value acquired by the statistical processing exceeds the threshold value, the statistical processing / notification unit requires the inspection / maintenance for at least the structural unit including the C arm and the holding mechanism. To inform you of this,
The inspection / maintenance time notification device according to claim 7.

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