JP2021180836A - X-ray diagnostic apparatus and x-ray diagnostic method - Google Patents

Abstract

To easily grasp a positional relation between an X-ray tube and an X-ray detector without using any position detection devices.SOLUTION: An X-ray diagnostic apparatus includes a processing circuit. The processing circuit controls an X-ray tube so as to perform X-ray irradiation that is performed before X-ray photographing to be performed on an analyte and is performed on the basis of a photographing condition in which at least one of an irradiation range and dosage of an X-ray is smaller than that of the X-ray photographing. The processing circuit also evaluates a positional relation between the X-ray tube and an X-ray detector from a detection result of the X-ray detector of an X-ray with which the X-ray irradiation is performed.SELECTED DRAWING: Figure 1

Description

The embodiments disclosed in the present specification and drawings relate to an X-ray diagnostic apparatus and an X-ray diagnostic method.

In some X-ray diagnostic devices, the X-ray tube and the X-ray detector do not face each other mechanically, and their positional relationship with each other is not fixed. In this type of X-ray diagnostic apparatus, the positions of the X-ray tube and the X-ray detector can be freely set independently.

On the other hand, when using this type of X-ray diagnostic device, X-ray irradiation by the X-ray tube is performed in order to reliably detect and image the X-rays emitted from the X-ray tube by the X-ray detector. It is important to minimize the deviation between the range and the detection range (image receiving area) of the X-ray detector. However, it is difficult to visually confirm whether or not the X-ray tube and the X-ray detector have a predetermined positional relationship. Further, it is conceivable to use a position detection device including an optical camera to detect the positions of the X-ray tube and the X-ray detector, but in this case, an additional configuration is required. Further, when an inspection is performed in a limited space such as an X-ray round-trip device, the position detection device may not function properly due to obstacles such as peripheral devices.

Japanese Unexamined Patent Publication No. 2014-033953

One of the problems to be solved by the embodiments disclosed in the present specification and the drawings is to easily grasp the positional relationship between the X-ray tube and the X-ray detector without using a position detection device. However, the problems to be solved by the embodiments disclosed in the present specification and the drawings are not limited to the above problems. The problem corresponding to each effect by each configuration shown in the embodiment described later can be positioned as another problem.

The X-ray diagnostic apparatus according to the embodiment has a processing circuit. The processing circuit is X-ray irradiation performed before X-ray imaging performed on the subject, and X-ray irradiation is performed based on imaging conditions in which at least one of the X-ray irradiation range and dose is smaller than that of X-ray imaging. Control the X-ray tube to do. Further, the processing circuit evaluates the positional relationship between the X-ray tube and the X-ray detector from the detection result of the X-ray irradiated by the X-ray irradiation by the X-ray detector.

The block diagram which shows one configuration example of the X-ray diagnostic apparatus which concerns on one Embodiment. The block diagram which shows the other configuration example of the X-ray diagnostic apparatus. Explanatory drawing which shows an example of the method of discriminating the positional relationship between an X-ray tube and an X-ray detector when the initial irradiation range is a range corresponding to a pencil beam. (A) is an explanatory diagram showing an example of an image displayed on the display after the start of fluoroscopy, and (b) is an explanatory diagram showing another example. (A) is an explanatory diagram showing an example of a case where it is determined that the X-ray tube and the X-ray detector do not have a predetermined positional relationship when the initial irradiation range is the range corresponding to the imaging site, and (b) is an explanatory diagram. An explanatory diagram showing another example when it is determined that the position is not in a predetermined position, and (c) is an explanatory diagram showing an example in the case where it is determined that the position is not in a predetermined position. The figure for demonstrating an example of the position adjustment method based on the center position of an initial irradiation range. The figure for demonstrating an example of the position adjustment method based on the 2nd irradiation range. The figure for demonstrating an example of the position adjustment method in the case where the irradiation opening shape of a diaphragm is rectangular, and the X-ray tube and the X-ray detector do not face each other. Explanatory drawing which shows an example of the control method of a diaphragm when the relative position of an X-ray tube and an X-ray detector changes after the start of fluoroscopy. (A) is a diagram for explaining the deviation detection region of the peripheral edge of the image receiving surface, and (b) is a method of controlling the diaphragm when the relative positions of the X-ray tube and the X-ray detector change after the start of fluoroscopy. Explanatory diagram showing another example. The explanatory view which shows an example of the method of evaluating the accuracy of the auto-positioning function of an X-ray diagnostic apparatus.

Hereinafter, embodiments of the X-ray diagnostic apparatus and the X-ray diagnostic method will be described in detail with reference to the drawings.

The X-ray diagnostic apparatus according to the embodiment has a processing circuit. The processing circuit is X-ray irradiation performed before X-ray imaging performed on the subject, and X-ray irradiation is performed based on imaging conditions in which at least one of the X-ray irradiation range and dose is smaller than that of X-ray imaging. Control the X-ray tube to do. Further, the processing circuit evaluates the positional relationship between the X-ray tube and the X-ray detector from the detection result of the X-ray irradiated by the X-ray irradiation by the X-ray detector.

In the X-ray diagnostic apparatus according to one embodiment, the X-ray tube and the X-ray detector are configured to be movable independently of each other, and are configured to be capable of X-ray imaging. The X-ray diagnostic apparatus includes a general imaging apparatus, an X-ray round-trip apparatus, an X-ray angio apparatus, an X-ray TV apparatus, and the like.

FIG. 1 is a block diagram showing a configuration example of the X-ray diagnostic apparatus 1 according to the embodiment. Further, FIG. 2 is a block diagram showing another configuration example of the X-ray diagnostic apparatus 1. FIG. 1 is an example of an X-ray diagnostic apparatus 1 for X-ray imaging of a standing subject, and FIG. 2 is an example of an X-ray diagnostic apparatus 1 for X-ray imaging of a recumbent subject.

As shown in FIGS. 1 and 2, the X-ray diagnostic apparatus 1 includes a photographing apparatus 10 and a console 20. When an X-ray image is taken of a standing subject, as shown in FIG. 1, the image pickup device 10 is an X-ray detector 13 movably supported by a stand 11, an X-ray tube holding device 12, and a stand 11. , A high voltage power supply 14, a throttle control device 15, a drive circuit 16, and a controller 17. On the other hand, when an X-ray image is taken of a subject in a recumbent position, as shown in FIG. 2, the imaging device 10 has a bed 42 provided with a top plate 41 on which the subject is placed, instead of the stand 11.

The X-ray tube holding device 12 of the photographing device 10 includes an X-ray tube 31, a diaphragm 32, and an operation panel 33.

When an X-ray image is taken of a standing subject, the standing subject is located in front of the stand 11 as shown in FIG. At least one of the X-ray tube holding device 12 and the X-ray detector 13 is controlled by the processing circuit 24 of the console 20 via the drive circuit 16 to change the positional relationship between the X-ray tube 31 and the X-ray detector 13. Move like. The movement of the X-ray tube holding device 12 and the X-ray detector 13 includes translation along the X-ray irradiation axis, translation in the direction orthogonal to the X-ray irradiation axis, and rotation.

When an X-ray image is taken of a subject in the recumbent position, the subject in the recumbent position is placed on the top plate 41 as shown in FIG. In this case as well, at least one of the X-ray tube holding device 12 and the X-ray detector 13 is controlled by the processing circuit 24 of the console 20 via the drive circuit 16 as in the case of standing shooting, and the X-ray tube is controlled. It moves so as to change the positional relationship between 31 and the X-ray detector 13.

The X-ray detector 13 is composed of a plane detector (FPD: flat panel detector) having a plurality of X-ray detectors arranged in two dimensions, and is irradiated to the X-ray detector 13 through a subject. Fluoroscopic data generated by X-ray fluoroscopy (hereinafter referred to as fluoroscopy) that detects X-rays and captures continuous X-ray images (frame images) in real time based on the detected X-rays, and Image data such as simple radiography data generated by simple radiography (hereinafter referred to as simple radiography) for shooting one X-ray image is given to the console 20. The X-ray detector 13 may include an image intensifier, a TV camera, or the like, or is an X-ray detection element composed of a semiconductor element that accumulates a signal charge according to the amount of X-ray incident. It may be a CMOS-FPD having a plurality of CMOS-FPDs.

The X-ray tube 31 is a vacuum tube that irradiates thermoelectrons from the cathode (filament) toward the anode (target) by applying a high voltage from the high voltage power supply 14.

The high-voltage power supply 14 is composed of an electric circuit such as a transformer and a rectifier, and corresponds to a high-voltage generator having a function of generating a high voltage applied to the X-ray tube 31 and X-rays emitted by the X-ray tube 31. It consists of an X-ray control device that controls the output voltage.

The squeezer 32 is a lead plate or the like for narrowing the irradiation range of the X-rays generated by the X-ray tube 31, and a slit is formed by a combination of a plurality of lead plates or the like. For example, the diaphragm 32 has a plurality of pairs of movable blades, is controlled by a processing circuit 24 via a diaphragm control device 15, and X-rays emitted from an X-ray tube 31 by opening and closing each pair of movable blades. Adjust the irradiation range of.

The operation panel 33 is provided in the housing of the X-ray tube holding device 12, and has hard keys such as buttons that give a unique instruction signal to the processor when the user presses the X-ray tube holding device 12, and a display input device. The display input device has a display as a display unit and a touch sensor as an input unit provided in the vicinity of the display unit.

The display of the operation panel 33 displays various images such as an image showing information about the X-ray diagnostic apparatus 1. Further, the user can input various instructions to the image displayed on the display to the X-ray diagnostic apparatus 1 via the touch sensor or the hard key of the operation panel 33. The operation panel 33 gives a signal corresponding to the user's input to the processing circuit 24 of the console 20. The X-ray diagnostic apparatus 1 does not have to include the operation panel 33.

The controller 17 has at least a processor and a storage circuit, and is controlled by the processing circuit 24 of the console 20 to collectively control each component of the photographing apparatus 10.

On the other hand, the console 20 has an input interface 21, a display 22, a storage circuit 23, and a processing circuit 24. The console 20 does not have to be provided independently. For example, the operation panel 33 of the photographing device 10 is responsible for the functions of the input interface 21 and the display 22 of the console 20, and the photographing device 10 is responsible for the functions of the storage circuit 23 and the processing circuit 24. The storage circuit and the processor of the controller 17 of the above may be carried by each. Further, in the following description, it is assumed that the console 20 executes all functions on a single console, but these functions may be executed by a plurality of consoles.

The input interface 21 of the console 20 is composed of general pointing devices such as a joystick, a trackball, a trackball mouse, a keyboard, a touch panel, and a ten key, and a hand switch for instructing the X-ray exposure timing. An operation signal corresponding to the user's operation is given to the processing circuit 24.

The display 22 is composed of a general display output device such as a liquid crystal display or an OLED (Organic Light Emitting Diode) display, and displays various information under the control of the processing circuit 24.

The storage circuit 23 has a configuration including a recording medium that can be read by a processor, such as a magnetic or optical recording medium or a semiconductor memory, and a part or all of the programs and data in these storage media have an electronic network. It may be configured to be downloaded via.

The processing circuit 24 is a process for easily grasping the positional relationship between the X-ray tube 31 and the X-ray detector 13 without using a position detection device by reading and executing the program stored in the storage circuit 23. Is a processor that executes. Further, the processing circuit 24 collectively controls each component of the photographing apparatus 10 via the controller 17.

The processing circuit 24 is configured to be able to determine whether or not the X-ray tube 31 and the X-ray detector 13 have a predetermined positional relationship.

Here, "the X-ray tube 31 and the X-ray detector 13 have a predetermined positional relationship (hereinafter referred to as a predetermined positional relationship)" means, for example, when fluoroscopy is performed by the X-ray diagnostic apparatus 1. , Refers to a positional relationship that meets the same standards as those applied to fluoroscopic devices such as X-ray angio devices. The positional relationship satisfying this standard includes a positional relationship in which the amount of protrusion from the end of the image receiving region (image receiving surface) 131 of the X-ray irradiation range during fluoroscopy or simple radiography is within a certain value. Further, the regulation requires that X-ray irradiation for fluoroscopy or simple radiography is prohibited when the X-ray irradiation range extends beyond a predetermined range from the end of the image receiving region 131 of the X-ray detector 13.

When the X-ray diagnostic apparatus 1 has an auto-positioning function, the X-ray tube 31 and X-rays are actually irradiated with X-rays in the estimated irradiation range corresponding to the imaging conditions set by using the auto-positioning function. Refers to the positional relationship of the detector 13. The auto-positioning function is a function that automatically moves the X-ray tube 31 and the X-ray detector 13 to the imaging position according to the inspection. For example, the processing circuit 24 uses the processing circuit 24 based on the information of the imaging target portion included in the inspection information. Will be executed.

Further, when performing pre-imaging for confirming the positional relationship between the X-ray tube 31 and the X-ray detector 13 and aligning as necessary before the simple imaging by the X-ray diagnostic apparatus 1, the simple imaging is used. The range (estimated irradiation range) on the image receiving area 131 estimated from the intended focus-image receiving surface distance (hereinafter referred to as SID) and the opening range of the aperture 32 is actually irradiated with X-rays. It refers to the positional relationship between the wire tube 31 and the X-ray detector 13.

The processing circuit 24 performs X-ray imaging such as fluoroscopy or simple radiography performed on the subject in order to determine whether or not the X-ray tube 31 and the X-ray detector 13 have a predetermined positional relationship. Before, the X-ray tube 31 is controlled so that X-ray irradiation is performed based on an imaging condition in which at least one of the X-ray irradiation range and the dose is smaller than that of the X-ray imaging.

Note that "X-ray irradiation performed before X-ray photography" is different from X-ray irradiation for X-ray photography such as fluoroscopy and simple radiography, and includes pre-shooting for setting conditions for simple radiography. good.

For example, by making the X-ray irradiation range of X-ray irradiation (initial irradiation) performed before X-ray imaging smaller than the X-ray irradiation range of the X-ray imaging, the X-ray conditions of initial irradiation and X-ray imaging are the same. Even so, the exposure dose of the subject can be reduced by the initial irradiation than by the X-ray irradiation. Similarly, by making the dose of initial irradiation smaller than that of X-ray photography, even if the X-ray irradiation range of initial irradiation and X-ray photography is the same, the exposure dose of the subject is higher in the initial irradiation than in X-ray irradiation. Can be reduced. Therefore, by performing the initial irradiation based on the imaging conditions in which at least one of the X-ray irradiation range and the dose is smaller than that of the X-ray imaging, the X-ray tube 31 and the X-ray detector 13 have an exposure dose smaller than that of the X-ray irradiation. It is possible to determine whether or not and are in a predetermined positional relationship.

In the following description, before X-ray imaging such as fluoroscopy or simple imaging, X-rays are irradiated so as to irradiate X-rays in an initial irradiation range 51 smaller than the X-ray irradiation range (second irradiation range) in the X-ray imaging. An example of controlling the tube 31 is shown.

In this case, as shown in FIGS. 1 and 2, the processor of the processing circuit 24 realizes the range control function 241, the discrimination function 242, the photographing control function 243, and the position adjustment function 244. Each of these functions is stored in the storage circuit 23 in the form of a program. A part of the function 241-244 of the processing circuit 24 may be realized by an external processor or a processor of the controller 17 connected to the photographing device 10 so as to be able to transmit and receive data.

Next, the configuration and operation of the function 241-244 of the processing circuit 24 will be described.

FIG. 3 is an explanatory diagram showing an example of a method for determining the positional relationship between the X-ray tube 31 and the X-ray detector 13 when the initial irradiation range 51 is a range corresponding to the pencil beam.

The range control function 241 is based on an imaging condition in which at least one of the X-ray irradiation range and the dose is smaller than that of the X-ray imaging before the X-ray imaging such as fluoroscopy or simple imaging performed on the subject. The X-ray tube 31 is controlled so as to perform ray irradiation.

In the following description, before X-ray imaging such as fluoroscopy or simple imaging, X-rays are irradiated so as to irradiate X-rays in an initial irradiation range 51 smaller than the X-ray irradiation range (second irradiation range) in the X-ray imaging. An example of controlling the tube 31 is shown.

At the stage of irradiating X-rays in the initial irradiation range 51, the positional relationship between the X-ray tube 31 and the X-ray detector 13 is unknown. Therefore, at this stage, the radiography control function 243 may prohibit fluoroscopy and simple radiography.

The upper part of FIG. 3 shows an example in which the initial irradiation range 51 is a range corresponding to a so-called pencil beam. For example, even if the diaphragm blades of the diaphragm 32 are fully closed, if a slightly thin pencil beam is emitted from the center of the X-ray shielding range, the diaphragm blades are fully closed to be in the upper stage of FIG. The initial irradiation range 51 can be as small as shown in.

The smaller the initial irradiation range 51, the easier it is to identify the central position of the X-ray irradiation range, and the more the exposure dose of the subject and the user can be reduced. Therefore, when irradiating X-rays in the initial irradiation range 51, it is preferable that the X-ray conditions including the tube voltage and the tube current are conditions in which the exposure is smaller than the X-ray conditions when performing normal fluoroscopy or simple radiography. , Preferably the minimum condition that can be set by the device. The shape of the initial irradiation range 51 may be a polygon such as a rectangular shape, or may be a circular shape or an elliptical shape.

In the discrimination function 242, for example, the X-ray tube 31 and the X-ray detector 13 are predetermined based on the detection result of the X-ray detector 13 irradiated in the initial irradiation range 51 (see the upper part of FIG. 3). By determining whether or not there is a positional relationship, the positional relationship between the X-ray tube 31 and the X-ray detector 13 is evaluated.

As shown in FIG. 3, when the initial irradiation range 51 is a small range such as a range corresponding to a pencil beam, the range control function 241 has a discrimination function 242 such that the X-ray tube 31 and the X-ray detector 13 are used. When it is determined that the X-ray detector has a predetermined positional relationship, as shown in the middle and lower stages of FIG. 3, in the second irradiation range 52 which is wider than the initial irradiation range 51 and fits in the image receiving area 131 of the X-ray detector 13. The irradiation range is expanded by controlling the X-ray tube 31 and the squeezing device 32 provided on the front surface of the X-ray tube 31 so as to irradiate X-rays. The size of the second irradiation range 52 may be, for example, a size corresponding to the imaging region under the condition that the imaging region is within the image receiving region 131 when the imaging region is determined.

The range control function 241 evaluates the position of the initial irradiation range 51. When all the X-rays irradiated in the initial irradiation range 51 are contained on the X-ray detector 13, the center of the irradiation range is obtained. In this case, the range control function 241 can obtain the second irradiation range 52 that fits in the image receiving region 131 based on this center. Therefore, the second irradiation range 52 does not protrude from the image receiving region 131 and satisfies the fluoroscopic standard.

The imaging control function 243 prohibits fluoroscopy or simple imaging unless the X-ray tube 31 and the X-ray detector 13 have a predetermined positional relationship. In this case, fluoroscopy will be interlocked. On the other hand, the imaging control function 243 permits fluoroscopy or simple imaging when the X-ray tube 31 and the X-ray detector 13 are in a predetermined positional relationship.

Hereinafter, an example in which the imaging control function 243 prohibits fluoroscopy when irradiating X-rays in the initial irradiation range 51 will be specifically described with reference to FIGS. 3 to 8.

For example, as shown in the upper part of FIG. 3, when the initial irradiation range 51 is detected by the X-ray detector 13, the discrimination function 242 has a predetermined positional relationship between the X-ray tube 31 and the X-ray detector 13. To determine. The imaging control function 243 permits fluoroscopy, which was prohibited at the stage of irradiating X-rays in the initial irradiation range 51, in response to this determination result. In this case, the photographing apparatus 10 can start fluoroscopy of the subject, for example.

On the other hand, in the example shown in the upper part of FIG. 3, when the initial irradiation range 51 is not detected by the X-ray detector 13, the discrimination function 242 has a predetermined positional relationship between the X-ray tube 31 and the X-ray detector 13. The imaging control function 243 prohibits fluoroscopy unless the X-ray tube 31 and the X-ray detector 13 have a predetermined positional relationship.

When the fluoroscopy information is immediately required, the imaging control function 243 permits fluoroscopy immediately after the discrimination function 242 determines that the X-ray tube 31 and the X-ray detector 13 are in a predetermined positional relationship. It is advisable to perform fluoroscopic output while expanding the irradiation range. Further, the imaging control function 243 may allow fluoroscopy when the irradiation range becomes a size larger than a predetermined irradiation range.

As described above, according to the photographing apparatus 10, even in the X-ray diagnostic apparatus 1 in which the X-ray tube 31 and the X-ray detector 13 are configured to be movable independently of each other, the X-ray tube 31 and the X-ray detector are detected. The positional relationship with the device 13 can be easily grasped without using an additional configuration such as a position detection device.

Further, if the positional relationship does not satisfy the same standard as the standard applied to a fluoroscopic device such as an X-ray angio device, fluoroscopy can be interlocked. Therefore, even in the X-ray diagnostic apparatus 1 in which the X-ray tube 31 and the X-ray detector 13 are configured to be movable independently of each other, it is possible to safely see through the subject in accordance with the standard. ..

FIG. 4A is an explanatory diagram showing an example of an image displayed on the display 22 after the start of fluoroscopy, and FIG. 4B is an explanatory diagram showing another example.

When fluoroscopy is started, an image showing the position of the irradiation range in the image receiving region 131 may be displayed for adjusting the position of the irradiation range (see FIG. 4A). Further, an image obtained by cutting out only the irradiation range and an image showing the position of the irradiation range in the image receiving area 131 may be displayed in different windows on the same display, or may be displayed in different displays (display 22 and operation panel 33). It may be displayed on a display (see FIG. 4 (b)).

The photographing device 10 can easily adjust the position while checking the fluoroscopic image. Therefore, it is possible to prevent unnecessary exposure due to re-shooting due to a position adjustment error.

FIG. 5A shows an example in which the X-ray tube 31 and the X-ray detector 13 are determined not to have a predetermined positional relationship when the initial irradiation range 51 is a range corresponding to the imaging site. It is a figure, (b) is explanatory drawing which shows the other example of the case which it is determined that it is not in a predetermined positional relationship, and (c) is the explanation which shows an example of the case that it is determined that it is in a predetermined positional relationship. It is a figure.

In the example shown in FIG. 5, unlike the example shown in FIG. 3, the initial irradiation range 51 is set to the range corresponding to the imaging site, and the diaphragm 32 has the range control function 241 so as to have an opening corresponding to the initial irradiation range 51. Be controlled.

In this case, the photographing apparatus 10 further includes a shielding plate 35 that shields the initial irradiation range 51. The shielding plate 35 is made of an X-ray shielding member such as lead, and has at least three transmission portions 35h provided on the peripheral portion. The transmission unit 35h transmits X-rays. The transmission portion 35h may be a hole portion provided in the shielding plate 35, or may be composed of an X-ray transmission member such as a filter. When the shielding plate 35 is rectangular, the transmission portion 35h may be provided in the vicinity of three of the four vertices (see FIG. 5A).

The discrimination function 242 determines whether or not the X-ray tube 31 and the X-ray detector 13 have a predetermined positional relationship based on the detection result of the X-ray detector 13 that has passed through the transmission unit 35h. .. For example, the discrimination function 242 determines that all the transparent portions 35h are not in a predetermined positional relationship when they are not detected (see FIGS. 5 (a) and 5 (b)), while all the transparent portions 35h are present. If it is detected, it is determined that it has a predetermined positional relationship (see FIG. 5 (c)).

Further, when the shielding plate 35 is used, at least three transmission ranges corresponding to the transmission portion 35h can be detected. In this case, if the figure connecting the three transmission ranges has a shape different from the original shape (for example, a right-angled isosceles triangle), the X-ray tube 31 does not face the X-ray detector 13 and tilts. It is supposed to be in position. Therefore, when the shape of the figure connecting the three transmission ranges is different from the original shape, the discrimination function 242 does not have a predetermined positional relationship even when all the transmission portions 35h are detected. It may be determined that.

When it is determined that the position is in a predetermined position, the photographing control function 243 allows fluoroscopy. In this case, as soon as the shielding plate 35 is retracted, simple radiography or fluoroscopy of the imaged portion becomes possible. Therefore, the inspection can be started earlier than the case where the positional relationship is determined from the pencil beam by the time for expanding the irradiation range.

The size of the target irradiation range differs depending on the subject and the test site. Therefore, it is advisable to prepare shielding plates 35 having a plurality of sizes in advance.

Next, a method of adjusting the position before permission for fluoroscopy by the imaging control function 243 will be described.

The position adjustment function 244 X-rays so that the X-ray tube 31 and the X-ray detector 13 have a predetermined positional relationship based on the detection result of the X-ray detector 13 irradiated in the initial irradiation range 51. The drive circuit 16 that drives the wire tube 31 and the X-ray detector 13 is controlled to automatically move at least one of the X-ray tube 31 and the X-ray detector 13.

FIG. 6 is a diagram for explaining an example of a position adjusting method based on the center position of the initial irradiation range 51.

When the X-rays irradiated in the initial irradiation range 51 fit on the X-ray detector 13 as shown in the upper part of FIG. 3 and the upper part of FIG. 6, the center of the initial irradiation range 51 is obtained as described above. In this case, the position adjustment function 244 and the X-ray tube 31 by moving at least one of the X-ray tube 31 and the X-ray detector 13 so that the center of the initial irradiation range 51 coincides with the center of the image receiving region 131. Adjust the positional relationship with the X-ray detector 13 (see the middle section of FIG. 6). After that, the range control function 241 controls the diaphragm 32 to irradiate X-rays in the second irradiation range 52 that fits in the image receiving area 131 of the X-ray detector 13 to expand the irradiation range (see the lower part of FIG. 6). ). When expanding the irradiation range after adjusting the position of the center, the maximum size of the second irradiation range 52 can be increased compared to the case where the position of the center is not adjusted (see the lower part of FIG. 3), and a wide field of view is secured. can do.

FIG. 7 is a diagram for explaining an example of a position adjusting method based on the second irradiation range 52.

After expanding the irradiation range to the second irradiation range 52 as shown in the lower part of FIG. 3 (see the uppermost stage and the second stage from the top in FIG. 7), move at least one of the X-ray tube 31 and the X-ray detector 13. After that (see the third row from the top of FIG. 7), the second irradiation range 52 may be further expanded (see the bottom row of FIG. 7). Also in this case, the maximum size of the second irradiation range 52 can be increased and a wide field of view can be secured as compared with the case where the position adjustment is not performed (see the lower part of FIG. 3).

FIG. 8 is a diagram for explaining an example of a position adjusting method when the irradiation opening shape of the diaphragm 32 is rectangular and the X-ray tube 31 and the X-ray detector 13 are not facing each other. ..

In the state shown in the second or third stage from the top of FIG. 7, the irradiation range has already been expanded, and the range of the shape corresponding to the irradiation aperture shape of the diaphragm 32 is projected on the image receiving region 131. In this state, the direction of the irradiation opening of the diaphragm 32 can be evaluated based on the shape of the detection range detected in the image receiving region 131.

Therefore, in the discrimination function 242, the shape of the actually measured detection range in which the X-ray detector 13 actually detects X-rays is the estimated detection range of X-rays in the X-ray detector 13 estimated from the opening shape of the diaphragm 32. Determine if it matches the shape. When the discrimination function 242 determines that the shape of the measured detection range does not match the shape of the estimated detection range, the position adjustment function 244 sets the drive circuit 16 so that the shape of the measured detection range approaches the shape of the estimated detection range. Controlled to adjust the angle of at least one of the X-ray tube 31 and the X-ray detector 13.

For example, when the irradiation aperture shape of the diaphragm 32 is rectangular, as shown in FIG. 8, if the shape of the detection range detected in the image receiving region 131 is trapezoidal, the X-ray tube 31 and the X-ray detector 13 Is not directly facing (inclined). In this case, the position adjustment function 244 controls the drive circuit 16 so that the trapezoidal shape of the measured detection range in which the X-ray detector 13 actually detects X-rays approaches a rectangle, and the X-ray tube 31 and the X-ray detector. Adjust at least one angle of 13.

On the other hand, when the discrimination function 242 determines that the shape of the actually measured detection range matches the shape of the estimated detection range, the radiography control function 243 may allow X-ray radiography such as fluoroscopy or simple radiography.

Further, even if the X-ray tube 31 and the X-ray detector 13 face each other and the shape of the measured detection range and the shape of the estimated detection range match, the SID (focus-image receiving surface distance) ) May differ from the target distance. Therefore, the position adjustment function 244 may obtain the size of the estimated X-ray detection range of the X-ray detector 13 from the target distance of the SID and the aperture size of the diaphragm 32. In this case, the position adjustment function 244 moves at least one of the X-ray tube 31 and the X-ray detector 13 along the X-ray irradiation axis direction so that the size of the measured detection range approaches the size of the estimated detection range. The SID can be adjusted.

At the start of the fluoroscopy procedure, the X-ray diagnostic apparatus 1 including the imaging apparatus 10 performs X-ray irradiation in the initial irradiation range 51 with, for example, a maximum irradiation range (pencil beam) and a minimum X-ray condition. Whether or not the X-ray tube 31 and the X-ray detector 13 are in a predetermined positional relationship based on the output of the X-ray detector 13 without using an additional sensor such as a position detection device (for example, can be aligned). Whether or not) can be determined. Further, when the X-ray tube 31 and the X-ray detector 13 are in a predetermined positional relationship, it is determined that fluoroscopy is possible and the output of fluoroscopy can be started, while the X-ray tube 31 and the X-ray detector 13 make it possible to start the output of fluoroscopy. Fluoroscopy can be interlocked if it is not in a predetermined positional relationship.

Further, when the center of the initial irradiation range 51 can be detected by X-ray irradiation of the initial irradiation range 51, the maximum irradiation range that can be expanded in the image receiving region 131 can be obtained from the initial irradiation range 51, so that the image receiving region 131 can be obtained. The irradiation range can be expanded within the range that does not deviate from the end of the.

Therefore, fluoroscopy is possible even with a general imaging device, an X-ray round-trip device, an X-ray TV device, or the like in which the X-ray tube 31 and the X-ray detector 13 are configured to be movable independently of each other. Further, the position of the X-ray tube 31 and the direction of the irradiation opening of the diaphragm 32 can be automatically adjusted based on the shape of the irradiation range by fluoroscopy and the opening degree information of the diaphragm 32.

As described above, the information obtained by the X-ray irradiation in the initial irradiation range 51 can be used to grasp the positional relationship between the X-ray tube 31 and the X-ray detector 13 for fluoroscopy.

Further, the imaging of the initial irradiation range 51 can also be used as a pre-imaging for setting conditions for performing simple imaging. In this case, the imaging control function 243 prohibits simple imaging when irradiating X-rays in the initial irradiation range 51.

Further, the method for grasping the positional relationship between the X-ray tube 31 and the X-ray detector 13 described above can be applied even after the start of fluoroscopy.

FIG. 9 is an explanatory diagram showing an example of a control method of the diaphragm 32 when the relative positions of the X-ray tube 31 and the X-ray detector 13 change after the start of fluoroscopy. The diagonal lines of the actually measured detection range 61 (the range in which the X-ray detector 13 actually detected X-rays) shown in FIG. 9 are provided for convenience of explanation and are actually detected by the X-ray detector 13. Note that it is not.

The discrimination function 242 evaluates in time series whether or not the positional relationship between the X-ray tube 31 and the X-ray detector 13 satisfies the criteria after the start of X-ray imaging such as fluoroscopy of the subject. Specifically, when the fluoroscopy is started, the discrimination function 242 acquires the actual measurement detection range 61 (the range in which the X-ray detector 13 actually detects X-rays) in time series, and sets the actual measurement detection range 61 in the actual measurement detection range 61. Based on this, it is determined whether or not the amount of time change in the relative positions of the X-ray tube 31 and the X-ray detector 13 is equal to or greater than the threshold value. The amount of change over time may be determined to be compared with the previous frame for each frame, may be determined every few frames, or a plurality of comparison results may be averaged. The photographing control function 243 determines that when the time change amount exceeds the threshold value, the relative positions of the X-ray tube 31 and the X-ray detector 13 are instantaneously greatly displaced, and the aperture 32 cannot handle the change. , The photographing device 10 is controlled so as to end the X-ray fluoroscopy and prohibit the subsequent X-ray fluoroscopy. In such a case, when the X-ray diagnostic device 1 is an X-ray round-trip device and the X-ray detector 13 is inserted between the subject and the hospital bed, the engineer instructs the subject to move. In response to this, it is conceivable that the X-ray detector 13 may also move when the subject turns over.

On the other hand, when a part of the actually measured detection range 61 moves out of the image receiving region 131 of the X-ray detector 13 and the time change amount of the relative position between the X-ray tube 31 and the X-ray detector 13 is smaller than the threshold value ( The imaging control function 243 controls the X-ray detector 32 so as to block the X-rays that have moved out of the image receiving region 131 of the X-ray detector 13 (see the lower part of FIG. 9).

Specifically, at the start of fluoroscopy, the entire measured detection range 61 is within the image receiving region 131. Therefore, both the center coordinates of the actually measured detection range 61 and the size of the actually measured detection range 61 (for example, the horizontal width and the vertical width in the case of a rectangle) can be obtained. Therefore, when the amount of time change in the relative positions of the X-ray tube 31 and the X-ray detector 13 is smaller than the threshold value, the aperture is easily controlled so that the measured detection range 61 does not deviate from the image receiving region 131 based on this information. Can be handled with.

Further, when X-rays are obliquely incident on the X-ray detector 13, the shape of the actually measured detection range 61 is distorted, for example, the rectangular shape should be trapezoidal, or the circular shape should be elliptical. In this case, for example, if the shape of the actually measured detection range 61 is a polygon, special care should be taken so that the longest side does not deviate from the image receiving region 131.

FIG. 10A is a diagram for explaining a deviation detection region 72 at the peripheral edge of the image receiving region 131, and FIG. 10B is a diagram in which the relative positions of the X-ray tube 31 and the X-ray detector 13 change after the start of fluoroscopy. It is explanatory drawing which shows the other example of the control method of the diaphragm 32 in the case.

In the example shown in FIG. 10, the peripheral portion of the image receiving region 131 is used as a shift detection region (hereinafter referred to as a shift detection region) 72, and the protrusion from the detection region 71 surrounded by the shift detection region 72 is monitored. The data detected in the shift detection area 72 may be used only for shift detection, or may be used for both shift detection and imaging.

The deviation detection region 72 is composed of regions 72X1 and 72X2 at both ends in the horizontal direction of the image receiving region 131, for example, regions 72X1 and 72X2 for 10 rows of detection elements, and regions 72Y1 and 72Y2 at both ends in the horizontal direction of the image receiving region 131 (FIG. 10 (a)).

When the deviation detection area 72 is available, the discrimination function 242 detects that the actual measurement detection range 61 has invaded the deviation detection area 72 before a part of the actual measurement detection range 61 protrudes from the image receiving area 131. be able to. In this case, the photographing control function 243 may control the diaphragm 32 so as to shield the X-rays that have entered the deviation detection region 72 (see FIG. 10B).

Further, also in the cases shown in FIGS. 10 (a) and 10 (b), as in the case shown in FIG. 9, the discrimination function 242 is the X-ray tube 31 and the X-ray detector 13 based on the actually measured detection range 61. It is determined whether or not the amount of time change in the relative position is equal to or greater than the threshold value. Specifically, the discrimination function 242 detects a deviation of a predetermined frame (for example, 1 frame) or more by a threshold intrusion width (for example, 7 columns) with respect to the width of the deviation detection area 72 (for example, 10 columns of the area 72X2). When the actual measurement detection range 61 invades the region 72, it is preferable to determine that the amount of time change is equal to or greater than the threshold value. In this case as well, as in the example shown in FIG. 9, the photographing control function 243 determines that the diaphragm 32 cannot handle the change in time when the change amount exceeds the threshold value, and terminates X-ray fluoroscopy and thereafter. The imaging device 10 may be controlled so as to prohibit fluoroscopy.

FIG. 11 is an explanatory diagram showing an example of a method for evaluating the accuracy of the auto-positioning function of the X-ray diagnostic apparatus 1.

The above-mentioned method for grasping the positional relationship between the X-ray tube 31 and the X-ray detector 13 can also be applied to evaluate the accuracy of the auto-positioning function of the X-ray diagnostic apparatus 1.

When the X-ray diagnostic apparatus 1 has an auto-positioning function, the positioning accuracy by the auto-positioning function may deteriorate due to a change with time, and the component may not be accurately positioned at a desired position. In this case, the internal parameters of the auto-positioning function can be corrected by using the method of grasping the positional relationship between the X-ray tube 31 and the X-ray detector 13 described above. For example, the accuracy of the auto-positioning function is evaluated by comparing the correct answer range 81, which is estimated to detect X-rays when the auto-positioning function works correctly in the image receiving region 131, with the actually measured detection range 61. can do.

Further, as shown in FIG. 11, the position of the threshold range 82 including the correct answer range 81 may be set in advance. In this case, when the actually measured detection range 61 exceeds the threshold range 82, the processing circuit 24 transmits information that an abnormality has occurred in the X-ray diagnostic apparatus 1 or information that the X-ray diagnostic device 1 has failed to a display such as the display 22. It may be displayed as an image, or may be output as audio through a speaker (not shown), or a serviceman call may be made.

As described above, based on the fluoroscopic information, it is possible to correct the change with time and detect the failure of the internal data of the X-ray diagnostic apparatus 1, and it is possible to maintain the performance of the apparatus.

It is also possible to perform automatic adjustment after auto-positioning based on the fluoroscopic information. Therefore, it is possible to reduce the variation in the accuracy of the position adjustment by the user and improve the inspection throughput.

According to at least one embodiment described above, the positional relationship between the X-ray tube and the X-ray detector can be easily grasped without using the position detection device.

In the above embodiment, the term "processor" refers to, for example, a dedicated or general-purpose CPU (Central Processing Unit), GPU (Graphics Processing Unit), or application specific integrated circuit (ASIC). Circuits such as programmable logic devices (eg, Simple Programmable Logic Device (SPLD), Complex Programmable Logic Device (CPLD), and Field Programmable Gate Array (FPGA)) means. When the processor is, for example, a CPU, the processor realizes various functions by reading and executing a program stored in a storage circuit. Further, when the processor is, for example, an ASIC, instead of storing the program in the storage circuit, the function corresponding to the program is directly incorporated as a logic circuit in the circuit of the processor. In this case, the processor realizes various functions by hardware processing that reads and executes a program embedded in the circuit. Alternatively, the processor can also combine software processing and hardware processing to realize various functions.

Further, in the above embodiment, an example in which a single processor of the processing circuit realizes each function has been shown, but a processing circuit is configured by combining a plurality of independent processors, and each processor realizes each function. May be good. When a plurality of processors are provided, the storage circuit for storing the program may be provided individually for each processor, or one storage circuit collectively stores the programs corresponding to the functions of all the processors. May be good.

Although some embodiments have been described, these embodiments are presented as examples and are not intended to limit the scope of the invention. These embodiments can be implemented in various other embodiments, and various omissions, replacements, changes, and combinations of embodiments can be made without departing from the gist of the invention. These embodiments and variations thereof are included in the scope of the invention described in the claims and the equivalent scope thereof, as are included in the scope and gist of the invention.

1 X-ray diagnostic device 13 X-ray detector 16 Drive circuit 24 Processing circuit 31 X-ray tube 32 Filter 35 Shielding plate 35h Transmission section 51 Initial irradiation range (first irradiation range)
52 Second irradiation range 61 Actual measurement detection range 131 Image receiving surface 241 Range control function 242 Discrimination function 243 Imaging control function 244 Position adjustment function

Claims (11)

The X-ray irradiation performed before the X-ray imaging performed on the subject, and the X-ray irradiation is performed based on the imaging conditions in which at least one of the X-ray irradiation range and the dose is smaller than the X-ray imaging. Control the X-ray tube,
From the detection result of the X-ray irradiated by the X-ray irradiation by the X-ray detector, the positional relationship between the X-ray tube and the X-ray detector is evaluated.
Processing circuit,
X-ray diagnostic device equipped with. The processing circuit is
From the X-ray detection result, it is determined whether or not the X-ray tube and the X-ray detector are facing each other.
When it is determined that they are facing each other, the X-ray imaging is executed, and when it is determined that they are not facing each other, the execution of the X-ray imaging is prohibited.
The X-ray diagnostic apparatus according to claim 1. The processing circuit is
From the X-ray detection result, the position of the X-ray irradiation range irradiated by the X-ray irradiation in the X-ray detector is evaluated.
The irradiation range is expanded so that the X-ray irradiation range falls within the range based on the image receiving region of the X-ray detector centering on the position of the X-ray irradiation range.
Performing the radiography of the subject based on the enlarged irradiation range.
The X-ray diagnostic apparatus according to claim 1. The processing circuit is
The positional relationship between the X-ray tube and the X-ray detector is adjusted so that the position of the X-ray irradiation range in the X-ray detector is located at the center of the image receiving region.
The X-ray imaging of the subject is performed based on the adjusted positional relationship.
The X-ray diagnostic apparatus according to claim 3. The processing circuit is
It is determined whether or not the shape of the X-ray irradiation range in the X-ray detector matches the shape of the X-ray irradiation range estimated based on the preset imaging conditions.
If it is determined that they match, the X-ray imaging is executed, and if it is determined that they do not match, the execution of the X-ray imaging is prohibited.
The X-ray diagnostic apparatus according to claim 1. The processing circuit is
When it is determined that they do not match, the X-ray tube and the X-ray detector are arranged so that the shape of the X-ray irradiation range in the X-ray detector becomes the shape of the estimated X-ray irradiation range. Adjust the positional relationship,
The X-ray imaging of the subject is performed based on the adjusted positional relationship.
The X-ray diagnostic apparatus according to claim 5. The processing circuit is
The relative distance between the X-ray tube and the X-ray detector so that the shape and size of the X-ray irradiation range in the X-ray detector are the shape and size of the estimated X-ray irradiation range. Adjust and
Performing the radiography on the subject based on the adjusted relative distance.
The X-ray diagnostic apparatus according to claim 6. The processing circuit is
The relative angle between the X-ray tube and the X-ray detector is adjusted so that the shape of the X-ray irradiation range in the X-ray detector becomes the shape of the estimated X-ray irradiation range.
Performing the radiography on the subject based on the adjusted relative angle.
The X-ray diagnostic apparatus according to claim 6. The processing circuit is
After performing the X-ray imaging on the subject, it is evaluated in time series whether or not the positional relationship between the X-ray tube and the X-ray detector satisfies the standard.
Controlling the continuation or stop of the X-ray imaging based on the evaluation result,
The X-ray diagnostic apparatus according to claim 1. A shielding plate having at least three or more X-ray transmission parts is provided.
The processing circuit is
The positional relationship between the X-ray tube and the X-ray detector is evaluated from the detection position of the X-ray transmitted through the X-ray transmitting portion detected by the X-ray detector.
The X-ray diagnostic apparatus according to claim 1. The X-ray irradiation performed before the X-ray imaging performed on the subject, and the X-ray irradiation is performed based on the imaging conditions in which at least one of the X-ray irradiation range and the dose is smaller than the X-ray imaging. Steps to control the X-ray tube and
A step of evaluating the positional relationship between the X-ray tube and the X-ray detector from the detection result of the X-ray irradiated by the X-ray detector by the X-ray detector, and
X-ray diagnostic method having.

Images