JP7005185B2 - X-ray diagnostic device - Google Patents

Description

Embodiments of the present invention relate to an X-ray diagnostic apparatus.

Generally, the X-ray diagnostic apparatus sets a field of view in an arbitrary range of the X-ray detection region of the X-ray detector, and controls the X-ray movable aperture so as to irradiate X-rays only in this range. After that, the X-ray diagnostic apparatus displays an image based on the X-ray detected in the range irradiated with the X-ray. Such an X-ray diagnostic apparatus has a function of changing the enlargement ratio of the displayed image centering on the region of interest.

JP-A-2007-159913

However, the X-ray diagnostic apparatus as described above usually has no particular problem, but according to the study of the present inventor, when the edge of the X-ray detection region is irradiated with X-rays, the center of the displayed image is not always present. There is an inconvenience that the area of interest is not located. For example, when the region of interest is located at the end of the X-ray detection region, the field of view is set so as not to include the outside of the X-ray detection region from the viewpoint of not irradiating the outside of the X-ray detection region with X-rays. Therefore, when the end of the X-ray detection region is irradiated with X-rays, the region of interest is located at the end of the displayed image.

Further, for example, even when the region of interest is located in the center of the display image corresponding to a certain visual field size, if the visual field size expands to the outside of the X-ray detection region due to the expansion of the visual field size, the visual field of the enlarged visual field size is forced. Is set in the X-ray detection area. Therefore, when the edge of the X-ray detection region is irradiated with X-rays, the display image is out of the center of interest while maintaining the enlarged field of view size.

An object of the present invention is to provide an X-ray diagnostic apparatus capable of locating a region of interest at the center of a displayed image even when the edge of the X-ray detection region is irradiated with X-rays.

According to the embodiment, the X-ray diagnostic apparatus includes an X-ray tube, an X-ray movable aperture, an X-ray detector, a visual field size setting unit, a virtual visual field setting unit, and an aperture control unit. X-ray tubes generate X-rays. The X-ray movable diaphragm limits the irradiation field of the generated X-ray. The X-ray detector detects X-rays. The field of view size setting unit sets any of a plurality of field of view sizes related to the X-ray irradiation field. The virtual field of view setting unit sets a virtual field of view having a set field of view size so as to extend beyond the X-ray detection area of the X-ray detector. The aperture control unit controls the X-ray movable aperture so as to irradiate the common area between the set virtual field of view and the X-ray detection area with X-rays.

It is a block diagram which shows an example of the structure of the X-ray diagnostic apparatus which concerns on one Embodiment. It is a figure which shows an example of the structure of the diaphragm blade in the same embodiment. It is a figure which illustrates the moving method of the diaphragm blade when all the diaphragm blades in the same embodiment move independently. It is a figure which illustrates the moving method of the diaphragm blade when the movement of the diaphragm blade is limited in the same embodiment. It is a figure which illustrates the moving method of the diaphragm blade when the movement of the diaphragm blade is limited in the same embodiment. It is a figure which shows an example of a plurality of field of view sizes in the same embodiment. It is a flowchart which shows an example of the operation of the X-ray diagnostic apparatus in the same embodiment. It is a figure which illustrates the positional relationship between the normal visual field N0 and the middle visual field M2 in the 1st specific example of the same embodiment. It is a figure which illustrates the positional relationship of the middle visual fields M2 and M2a before and after movement in the specific example. It is a figure which illustrates the positional relationship between the middle visual field M2 and the narrow visual field M3 in the specific example. It is a figure which shows the display example of the display image corresponding to the medium field of view M2 of FIG. 7A. It is a figure which shows the display example of the display image corresponding to the middle visual field M2a of FIG. 7B. It is a figure which shows the display example of the display image corresponding to the narrow field of view M3 of FIG. 7C. It is a figure which illustrates the positional relationship between the normal visual field N0 and the narrow visual field M3 in the 2nd specific example of the same embodiment. It is a figure which illustrates the positional relationship with the narrow field of view M3, M3a before and after the movement in the specific example. It is a figure which illustrates the positional relationship between the narrow field of view M3 and the middle field of view M2 in the specific example. It is a figure which shows the display example of the display image corresponding to the narrow field of view M3 of FIG. 9A. It is a figure which shows the display example of the display image corresponding to the medium field of view M2 of FIG. 9C. It is a figure which shows another display example of the display image corresponding to the medium field of view M2 of FIG. 7A. It is a figure which shows another display example of the display image corresponding to the midfield M3 of FIG. 7C.

Hereinafter, one embodiment will be described with reference to the drawings. Elements that are the same as or similar to the already explained elements are designated by the same or similar reference numerals, duplicate explanations are omitted, and unexplained elements are mainly described.

FIG. 1 is a block diagram showing a configuration example of the X-ray diagnostic apparatus 1 according to the embodiment. The X-ray diagnostic device 1 includes an X-ray high voltage device 2, a sleeper having an X-ray source device 3, an X-ray detector 4, a support frame 5, and a top plate 6, an image generation circuit 7, and a communication interface circuit 8. The input interface circuit 9, the control circuit 10, the processing circuit 11, the storage circuit 12, and the display circuit 13 are provided. Further, the X-ray source device 3 includes an X-ray tube 3a and an X-ray movable diaphragm 3b. The X-ray diagnostic apparatus 1 corresponds to, for example, an X-ray fluoroscopic diagnostic apparatus used in gastrointestinal angiography and the like. Further, the X-ray diagnostic apparatus 1 may be, for example, an X-ray fluoroscopic diagnostic apparatus for a circulatory organ used in angiography or the like.

The X-ray high voltage device 2 generates a tube current applied to the X-ray tube 3a and a tube voltage applied to the X-ray tube 3a. Under the control of the control circuit 10, the X-ray high voltage device 2 applies a tube current suitable for X-ray imaging and X-ray fluoroscopy to the X-ray tube 3a, and is suitable for X-ray imaging and X-ray fluoroscopy, respectively. The tube voltage is applied to the X-ray tube 3a. The X-ray high-voltage device 2 corresponds to, for example, an inverter-controlled high-voltage device.

The X-ray tube 3a generates X-rays based on the tube current applied from the X-ray high voltage device 2 and the tube voltage applied from the X-ray high voltage device 2. The X-rays generated by the X-ray tube 3a irradiate the subject P. The X-ray tube 3a corresponds to, for example, a rotating anode type X-ray tube. Further, the X-ray tube 3a may be, for example, a fixed anode type X-ray tube or the like.

Hereinafter, the central axis in the X-ray irradiation direction is defined as the Z axis. Further, the axis perpendicular to the Z axis in the longitudinal direction of the top plate 6 is defined as the Y axis, and the axis perpendicular to the Z axis and the Y axis is defined as the X axis.

The X-ray movable diaphragm 3b limits the irradiation field of X-rays generated by the X-ray tube 3a. By limiting the X-ray irradiation field, the X-ray movable diaphragm 3b can irradiate X-rays only to the imaging site (or imaging range) of the subject P desired by the operator. That is, the X-ray movable diaphragm 3b can prevent unnecessary exposure to a portion (or range) different from the imaging region (or imaging range). Further, the X-ray movable diaphragm 3b can reduce scattered X-rays and remove out-of-focus X-rays. Hereinafter, the words "limit the X-ray irradiation field" may be read interchangeably with the words "shield the X-rays" and "squeeze the X-rays".

The X-ray movable diaphragm 3b has, for example, a diaphragm mechanism 20 as illustrated in FIG. The diaphragm mechanism 20 has, for example, diaphragm blades 21a and 21b for narrowing X-rays spreading in the X-axis direction and diaphragm blades 22a and 22b for narrowing X-rays spreading in the Y-axis direction. Hereinafter, the range surrounded by the diaphragm blades 21a, 21b, 22a, 22b will be referred to as an X-ray irradiation field. The diaphragm mechanism 20 in FIG. 2 is a simplified representation of the diaphragm mechanism. For example, a plurality of diaphragm mechanisms 20 may be provided to form a multi-layer structure. Further, it is assumed that X-rays are not irradiated to the portion other than the irradiation field.

Here, a method in which the diaphragm blades 21a, 21b, 22a, 22b focus X-rays on the ROI of interest will be described. Hereinafter, the positions of the diaphragm blades 21a, 21b, 22a, 22b exemplified in FIG. 2 are defined as the initial positions. Further, at the initial position, it is assumed that the intersection of the first central axis 23 and the second central axis 24 is located at the center of the X-ray irradiation field. Further, it is assumed that the irradiation field has already been narrowed down to some extent at the position of the diaphragm blade in FIG. 2, and there is no unnecessary exposure.

FIG. 3 illustrates a method of moving the diaphragm blades when the diaphragm blades 21a, 21b, 22a, and 22b can move independently. The diaphragm blade 21a moves along the movement direction x1 which is the X-axis direction with respect to the initial position. The diaphragm blade 22b moves along the movement direction y1 which is the Y-axis direction with respect to the initial position. At this time, the diaphragm mechanism 20 can focus X-rays on the ROI of interest only by moving the diaphragm blades 21a and 22b. Therefore, the diaphragm blades 21b and 22a are not movable and are maintained in the initial positions.

4A and 4B exemplify a method of moving the diaphragm blade when the movement of the diaphragm blade is limited. In FIGS. 4A and 4B, the diaphragm blades 21a and the diaphragm blades 21b move in conjunction with each other, and the diaphragm blades 22a and the diaphragm blades 22b move in conjunction with each other. That is, the two pairs of diaphragm blades can move symmetrically and vertically, respectively.

First, the aperture mechanism 20 moves along the moving direction xy so that the region of interest ROI is located at the center of the irradiation field. After that, the diaphragm blades 21a and 21b move along the moving directions x2a and x2b, respectively. At the same time, the diaphragm blades 22a and 22b move along the moving directions y2a and y2b, respectively. By moving as described above, X-rays can be focused on the region of interest ROI.

The X-ray detector 4 detects X-rays generated from the X-ray tube 3a and transmitted through the subject P. The X-ray detector 4 includes, for example, a flat panel detector (FPD) capable of detecting X-rays. The FPD has a plurality of semiconductor detection elements. The semiconductor detection element includes an indirect conversion type and a direct conversion type. The indirect conversion type is a format in which incident X-rays are converted into light by a scintillator such as a phosphor, and the converted light is converted into an electric signal. The direct conversion type is a type in which incident X-rays are directly converted into an electric signal. An image intensifier may be used as the X-ray detector 4. Further, in the present specification, the range in which X-rays can be detected by the X-ray detector 4 is referred to as an “X-ray detection area”.

The electric signals generated by the plurality of semiconductor detection elements due to the incident of X-rays are output to an analog-digital converter (A / D converter) (not shown). The A / D converter converts the electrical signal into digital data. The A / D converter outputs digital data to the image generation circuit 7.

FIG. 5 illustrates the relationship between the X-ray detection region and a plurality of irradiation fields. In the present specification, for example, the visual fields of four different visual field sizes are defined as normal visual field N0, wide visual field M1, medium visual field M2, and narrow visual field M3 in descending order of irradiation field. The normal visual field N0 is related to, for example, an irradiation field in which X-rays can be detected from the entire surface of the X-ray detection region. Further, the wide field of view M1 is related to an irradiation field narrower than the irradiation field of the normal field of view N0. The medium visual field M2 is associated with an irradiation field that is narrower than the irradiation field of the wide visual field M1. The narrow field M3 is associated with a field that is narrower than the field of the medium field M2. Since the visual field size is related to the size of the irradiation field, "expanding the visual field size" is related to "expanding the irradiation field".

The X-ray image corresponding to each field size is displayed (for example, enlarged) so as to fit the display window of the display described later. Specifically, the display by the wide field of view M1 is enlarged and displayed as compared with the display by the normal field of view N0. Therefore, switching the field of view size is synonymous with switching the magnification of the image displayed in the display window. Further, when the visual fields N0 to M3 are arranged in descending order of enlargement ratio, they are M3, M2, M1, and N0.

The support frame 5 movably supports the X-ray source device 3 and the X-ray detector 4 arranged so as to face each other. Specifically, the support frame 5 corresponds to an overtube type frame in which the X-ray source device 3 is installed above the surface of the top plate 6. As the support frame 5, an undertube type frame in which the X-ray source device 3 is installed below the surface of the top plate 6 may be used. Further, the support frame 5 may have a structure consisting of a C arm and an Ω arm. Further, the support frame 5 may have a structure consisting of two arms (for example, a robot arm) that independently support the X-ray source device 3 and the X-ray detector 4.

The sleeper (not shown) has a top plate 6 (also referred to as a recumbent table) on which the subject P is placed. The subject P is placed on the top plate 6.

A drive device (not shown) drives the support frame 5 and the bed, respectively, under the control of the control circuit 10, for example. During X-ray fluoroscopy and X-ray imaging, the subject P placed on the top plate 6 is arranged between the X-ray source device 3 and the X-ray detector 4. Further, the drive device drives the X-ray movable diaphragm 3b under the control of the control circuit 10, for example. The drive device may rotate the X-ray detector 4 with respect to the X-ray source device 3 under the control of the control circuit 10.

The image generation circuit 7 generates an X-ray image based on the digital data output from the X-ray detector 4 via the A / D converter. The image generation circuit 7 outputs the generated X-ray image to the processing circuit 11, the storage circuit 12, an external storage device (not shown), and the like.

The communication interface circuit 8 is, for example, a circuit related to a network and an external storage device (not shown). The X-ray image obtained by the X-ray diagnostic apparatus 1 can be transferred to another apparatus via the communication interface circuit 8 and the network. Hereinafter, when information is exchanged via the communication interface circuit 8, the description "via the communication interface circuit 8" is omitted.

The input interface circuit 9 is an X-ray irradiation condition such as an X-ray imaging condition and an X-ray fluoroscopy condition desired by the operator, a fluoroscopy / imaging position, an irradiation field, and a region of interest in the X-ray image. : ROI) etc. is input according to the instruction of the operator. Specifically, the input interface circuit 9 captures various instructions, commands, information, selections, and settings from the operator into the X-ray diagnostic apparatus 1.

The input interface circuit 9 integrates a joystick for setting an area of interest, a trackball, a switch button, a mouse, a keyboard, a touch pad for performing input operations by touching the operation surface, and a display screen and a touch pad. It is realized by a touch panel display, a foot switch for shooting, and a microphone for voice recognition. The input interface circuit 9 is connected to the control circuit 10, converts the input operation received from the operator into an electric signal, and outputs the input operation to the control circuit 10.

As used herein, the input interface circuit 9 is not limited to those provided with physical operating components such as a mouse and a keyboard. For example, an example of the input interface circuit 9 includes an electric signal processing circuit that receives an electric signal corresponding to an input operation from an external input device provided separately from the device and outputs the electric signal to the control circuit 10. Is done.

The control circuit 10 is, for example, a processor that controls each circuit and the driving device in the X-ray diagnostic apparatus 1. The control circuit 10 temporarily stores information such as an operator's instruction input from the input interface circuit 9 in a memory (not shown). The control circuit 10 controls an X-ray high voltage device 2, an X-ray movable aperture 3b, a drive device, and the like in order to perform X-ray imaging and X-ray fluoroscopy according to an operator's instruction stored in a memory. .. Further, the control circuit 10 controls the X-ray image generation processing in the image generation circuit 7 and the image processing in the processing circuit 11.

Further, the control circuit 10 executes each function for setting and controlling the X-ray diaphragm according to the instruction of the operator stored in the memory. Each of the above functions includes, for example, a field of view size setting function 10a, a virtual field of view setting function 10b, an aperture position calculation function 10c, and an aperture control function 10d.

The visual field size setting function 10a sets any of a plurality of visual field sizes related to the X-ray irradiation field by the operation of the operator. At this time, the operator selects an arbitrary field of view size (or an arbitrary enlargement ratio) by, for example, pressing a switch button of the input interface circuit 9. As the input method, a method of touching the touch panel for selection or a method of selecting by voice recognition may be used.

The virtual field of view setting function 10b sets the virtual field of view by the operation of the operator. Here, the "virtual field of view" is a field of view that can include the outside of the X-ray detection region, which has not been assumed in the past, and does not necessarily match the range in which X-rays are actually irradiated. Further, the "virtual field of view" is synonymous with an image displayed on a display described later. Specifically, the virtual field of view setting function 10b sets, for example, a virtual field of view having a field of view size set by the field of view size setting function 10a so that it can protrude from the X-ray detection area of the X-ray detector 4. Here, "setting the virtual field of view" may be read as "setting the field of view position of the virtual field of view", and the virtual field of view setting function 10b is a virtual field of view corresponding to the field of view size set by the field of view size setting function 10a. The visual field position of the virtual visual field is set so that the region of interest is positioned at the center of the virtual visual field, ignoring the positional relationship between the visual field and the X-ray detection region of the X-ray detector 4. The above positional relationship is, for example, a positional relationship when the virtual visual field is in a position including an area outside the X-ray detection region and a position where the virtual visual field is not included in the region outside the X-ray detection region. There are two ways with the positional relationship. The former positional relationship corresponds to the case where the virtual visual field extends beyond the X-ray detection area, and the latter positional relationship corresponds to the case where the virtual visual field does not extend beyond the X-ray detection area. Further, "positioning the region of interest in the center of the virtual visual field ignoring the positional relationship" means positioning the region of interest in the center of the virtual visual field in any of the two positional relationships. In the past, since the "positional relationship between the visual field and the X-ray detection region" is not ignored, the visual field does not include the region outside the X-ray detection region. In addition, of the above two positional relationships, "positioning the region of interest in the center of the virtual visual field while ignoring the positional relationship between the virtual visual field and the X-ray detection region" means that "the virtual visual field is the X-ray detection region." It may be read as "positioning the region of interest in the center of the virtual field of view even when the outer region is included". At this time, the operator moves the virtual field of view to a desired position by, for example, operating the joystick of the input interface circuit 9. The visual field position is an arbitrary position where the center of the virtual visual field is within the X-ray detection area.

The virtual field of view setting function 10b may set a virtual field of view (or a field of view position of the virtual field of view) when a plurality of field of view sizes are switched. Further, the virtual field of view setting function 10b may set the virtual field of view (or the field of view position of the virtual field of view) so that the center of the virtual field of view is located within the X-ray detection region.

The aperture position calculation function 10c calculates the aperture position corresponding to the virtual field of view (or the virtual field of view of the set field of view position) set by the field of view size setting function 10a and the virtual field of view setting function 10b.

The aperture control function 10d controls the X-ray movable aperture 3b based on the set virtual field of view. At this time, the aperture control function 10d controls the X-ray movable aperture 3b so as to irradiate the common area between the set virtual field of view and the X-ray detection area with X-rays. In other words, the aperture control function 10d controls the X-ray movable aperture 3b based on the virtual visual field (or the calculated aperture position) of the set visual field position. At this time, if the virtual visual field at the set visual field position includes the region outside the X-ray detection region, the aperture control function 10d does not further irradiate the region outside the X-ray detection region with X-rays. The X-ray movable aperture 3b is controlled in this way.

The processing circuit 11 includes a processor and a memory as hardware resources. The processing circuit 11 reads out the control program stored in the storage circuit 12 in response to the start instruction input by the operator via the input interface circuit 9. The processing circuit 11 executes each function related to image processing for displaying the X-ray image generated by the image generation circuit 7 on the display according to the read control program. Each of the above functions includes, for example, an image cutout position calculation function 11a, an image cutout function 11b, an image processing function 11c, an image enlargement function 11d, and the like.

The image cutout position calculation function 11a is based on the aperture position calculated by the aperture position calculation function 10c, the position of the X-ray source device 3, and the position of the X-ray detector 4, and the X-ray of the X-ray detector 4. The range of X-rays applied to the detection area is calculated as the image cutout position.

The image cropping function 11b cuts out an X-ray image based on the image cropping position.

The image processing function 11c generates a processed image (display image) including the X-ray image cut out by the image cutting function 11b. Specifically, the image processing function 11c performs processing to complement an image (padding image) showing an area outside the X-ray detection region with respect to the X-ray image. If the virtual field of view does not include an area outside the X-ray detection area, processing by the image processing function 11c is omitted.

Here, the padding image is an image for filling a blank space between the display image corresponding to the virtual field of view and the X-ray image corresponding to a part of the virtual field of view, and is an image having a form different from the X-ray image. be. Further, the padding image is an image that does not affect the test result of the subject. As the padding image, for example, a black-and-white two-gradation mesh image may be used, or when displaying on a color display, hue information may be used. The mesh image is an example of the case where the padding image has a pattern, and may be changed to a pattern image of a plurality of lines (straight line or curve, etc.) such as an image of parallel lines or a substantially random intersection line. Similarly, the mesh image may be changed to a pattern image in which figures, symbols, characters and the like are scattered substantially uniformly or at random. Not limited to these, the mesh image may be changed to a one-color image such as white or black on the entire surface, or may be changed to an image of any other pattern. Further, the padding image may include memo information such as a character string related to a subject or a test as a part thereof. The padding image is not limited to the case where the padding image is distinguished from the X-ray image by the form in the plane such as the above-mentioned black-and-white two-gradation pattern image and the hue information, and the X-ray is formed by the form of expressing the outline of the padding image by using a frame. It may be distinguished from the image. Alternatively, the padding image may be a form in which a form in a plane and a form representing a contour are combined.

The image enlargement function 11d enlarges the processed image processed by the image processing function 11c or the unprocessed X-ray image so as to fit the display window of the display.

The storage circuit 12 is composed of a memory for recording electrical information such as an HDD (Hard Disk Drive) and peripheral circuits such as a memory controller and a memory interface attached to the memory. The memory is not limited to HDD, but SSD (solid state drive), magnetic disk (floppy (registered trademark) disk, hard disk, etc.), optical disk (CD, DVD, Blu-ray (registered trademark), etc.), semiconductor memory, etc. Can be used as appropriate.

The storage circuit 12 includes various X-ray images generated by the image generation circuit 7, X-ray images processed by the processing circuit 11, a system control program of the X-ray diagnostic apparatus 1, and a diagnostic protocol executed by the control circuit 10. Various data groups such as operator's instructions sent from the input interface circuit 9, shooting conditions related to X-ray photography and fluoroscopic conditions related to X-ray fluoroscopy, error information, and various data sent via the network. Remember.

The display circuit 13 includes a display for displaying a medical image and the like, an internal circuit for supplying a display signal to the display, and peripheral circuits such as a connector and a cable connecting the display and the internal circuit.

The display displays an X-ray image generated by the image generation circuit or a display image processed by the processing circuit 11. The entire surface of the display may be a display window for displaying an X-ray image, a part of the display may be a display window, or both may be switched. The display may display an input screen for inputting fluoroscopy / photographing position, X-ray irradiation conditions, and the like. Further, for example, the display may display the X-ray image and the input screen side by side.

Next, the operation of the X-ray diagnostic apparatus 1 configured as described above will be described with reference to the flowchart of FIG. The following description mainly describes the setting and control of the X-ray diaphragm by the control circuit 10 and the image generation processing by the processing circuit 11.

First, the subject P is placed on the top plate 6 of the bed. The X-ray diagnostic apparatus 1 selects preset inspection types and inspection names by the operation of the operator, and sets imaging conditions associated with the selected inspection types and inspection names. After that, the X-ray diagnostic apparatus 1 starts X-ray fluoroscopy and starts step ST1 by the operation of the operator.

In step ST1, the X-ray diagnostic apparatus 1 receives an operation related to the aperture. Specifically, the field of view size setting function 10a sets any of a plurality of field of view sizes by the operation of the operator. Setting the field of view size may be referred to as switching between a plurality of field of view sizes. In any case, at this time, the operator selects an arbitrary field size (or an arbitrary enlargement ratio) by, for example, pressing a switch button of the input interface circuit 9. Then, the virtual field of view setting function 10b sets the virtual field of view (or the field of view position) with the setting of the field of view size as an opportunity.

Further, not limited to this, the virtual field of view setting function 10b may set the virtual field of view (or the field of view position) by the operation of the operator after the field of view size has already been set. At this time, the operator moves the center of the virtual field of view to the position of the desired region of interest by, for example, operating the joystick of the input interface circuit 9. Before and after the movement, the virtual field of view (or the field of view position) is set so that the center of the virtual field of view is within the X-ray detection area of the X-ray detector 4.

The above-mentioned field of view size and virtual field of view (or field of view position) may be set almost simultaneously, for example, by using a reference image. As the reference image, an X-ray image (or an X-ray fluoroscopic image) in a normal field of view may be used, or a temporary image that can be captured in the size of a normal field of view may be used. Further, when the reference image is acquired in advance, fluoroscopy may be temporarily interrupted.

In step ST2, the aperture position calculation function 10c calculates the aperture position corresponding to the virtual field of view (or the virtual field of view of the field of view) set in step ST1.

In step ST3, the control circuit 10 determines whether or not the virtual visual field is set outside the X-ray detection region (outside the detection range) of the detector. Specifically, the control circuit 10 determines whether or not the aperture position calculated in step ST2 includes the area outside the detection range of the X-ray detector 4. If the aperture position includes the area outside the detection range of the X-ray detector 4, the process proceeds to step ST4, and if not, the process proceeds to step ST9.

In step ST4, the aperture control function 10d irradiates X-rays based on the set virtual field of view (or the field of view of the field of view or the calculated aperture position) and outside the detection range of the X-ray detector 4. The X-ray movable aperture 3b is controlled so as not to be performed.

In step ST5, the processing circuit 11 acquires an X-ray image generated by the image generation circuit 7.

In step ST6, the image cropping position calculation function 11a is based on the aperture position calculated in step ST2, the position of the X-ray source device 3, and the position of the X-ray detector 4, and the X-ray detector 4 is X-ray. The range of X-rays emitted to the line detection area is calculated as the image cutout position.

In step ST7, the image cropping function 11b cuts out an X-ray image based on the image cropping position calculated in step ST6.

In step ST8, the image processing function 11c corresponds to the virtual field of view at the set field of view position, and generates a processed image including the X-ray image cut out in step ST7. Specifically, the image processing function 11c performs processing to complement the padding image showing the region outside the X-ray detection region with respect to the X-ray image. As a result, the image processing function 11c generates a processed image (display image) corresponding to the visual field so as to connect the X-ray image and the padding image. At this time, the padding image in the processed image may be generated as a black-and-white two-gradation mesh image or may be generated as a color image using hue information.

In step ST9, the aperture control function 10d controls the X-ray movable aperture 3b based on the virtual visual field (or the calculated aperture position) of the set visual field position.

In step ST10, the processing circuit 11 acquires an X-ray image generated by the image generation circuit 7.

In step ST11, the image cropping position calculation function 11a is based on the aperture position calculated in step ST2, the position of the X-ray source device 3, and the position of the X-ray detector 4, and the X-ray detector 4 is X-ray. The range of X-rays emitted to the line detection area is calculated as the image cutout position.

In step ST12, the image cropping function 11b cuts out an X-ray image based on the image cropping position calculated in step ST6.

In step ST13, the image enlargement function 11d enlarges the processed image generated in step ST8 or the X-ray image cut out in step ST12 so as to fit the display window of the display.

In step ST14, the display circuit 13 displays the enlarged processed image or X-ray image in step ST13.

Next, specific examples of the above-described operation will be described with reference to FIGS. 7A to 7C, FIGS. 8A to 8C, FIGS. 9A to 9C, FIGS. 10A to 10B, and FIGS. 11A to 11B. In these specific examples, the setting of the visual field size and the visual field position is mainly described, and the description of the image processing by the processing circuit 11 will be omitted.

(First specific example)
In the first specific example, the normal visual field N0 is switched to the medium visual field M2 (FIG. 7A), the medium visual field M2 is moved (FIG. 7B), and the medium visual field M2 is changed to the narrow visual field M3 by the operation of the operator. A series of operations for switching (FIG. 7C) are shown. In this specific example, when the middle visual field M2 is moved, the visual field is set to the visual field position including the outside of the X-ray detection region. For ease of understanding, normal visual fields N0 corresponding to the X-ray detection region are shown in FIGS. 7A to 7C.

FIG. 7A is a diagram illustrating the positional relationship between the normal visual field N0 and the medium visual field M2 when the irradiation field is narrowed from the normal visual field N0 to the medium visual field M2. The operator selects the visual field size of the medium visual field M2, for example, by pressing the switch button of the input interface circuit 9. The field of view size setting function 10a sets the field of view size of the medium field of view M2 by the operation of the operator. At this time, as illustrated in FIG. 8A, the display window 31 of the display 30 displays an X-ray image obtained from the irradiation field of the medium visual field M2.

FIG. 7B is a diagram illustrating the positional relationship between the pre-movement midfield M2 and the post-movement midfield M2a when the midfield M2 (M2 before movement) of FIG. 7A is moved. The operator moves the middle visual field M2 so that the region of interest is located at the center of the virtual visual field, for example, by operating the joystick of the input interface circuit 9. The virtual field of view setting function 10b sets the middle field of view M2a so that the region of interest is located at the center of the virtual field of view by the operation of the operator. At this time, the medium visual field M2a after movement includes a region outside the X-ray detection region. Therefore, as illustrated in FIG. 8B, in the display window 32, the mesh image 33 representing the region outside the X-ray detection region is displayed together with the X-ray image.

FIG. 7C is a diagram illustrating the positional relationship between the medium field of view M2 and the narrow field of view M3 when the irradiation field is narrowed from the medium field of view M2 to the narrow field of view M3. The operator selects the field of view size of the narrow field of view M3, for example, by pressing the switch button of the input interface circuit 9. The field of view size setting function 10a sets the field of view size of the narrow field of view M3 by the operation of the operator. At this time, the narrow field of view M3 includes a region outside the X-ray detection region. Therefore, as illustrated in FIG. 8C, in the display window 34, the mesh image 35 representing the region outside the X-ray detection region is displayed together with the X-ray image.

(Second specific example)
In the second specific example, the normal visual field N0 is switched to the narrow visual field M3 (FIG. 9A), the narrow visual field M3 is moved (FIG. 9B), and the narrow visual field M3 is switched to the medium visual field M2 by the operation by the operator. A series of operations for switching (FIG. 9C) are shown. In this specific example, when switching from the narrow field of view M3 to the medium field of view M2, the virtual field of view is set to include the outside of the X-ray detection area. For ease of understanding, normal visual fields N0 corresponding to the X-ray detection region are shown in FIGS. 9A to 9C.

FIG. 9A is a diagram illustrating the positional relationship between the normal field of view N0 and the narrow field of view M3 when the irradiation field is narrowed from the normal field of view N0 to the narrow field of view M3. The operator selects the field of view size of the narrow field of view M3, for example, by pressing the switch button of the input interface circuit 9. The field of view size setting function 10a sets the field of view size of the narrow field of view M3 by the operation of the operator. At this time, as illustrated in FIG. 10A, the display window 41 of the display 40 displays an X-ray image obtained from the irradiation field of the narrow field of view M3.

FIG. 9B is a diagram illustrating the positional relationship between the narrow field of view M3 before movement and the narrow field of view M3a after movement when the narrow field of view M3 (M3 before movement) of FIG. 9A is moved. The operator moves the narrow field of view M3 so that the region of interest is located at the center of the virtual field of view, for example, by operating the joystick of the input interface circuit 9. The virtual field of view setting function 10b sets the narrow field of view M3 so that the region of interest is located at the center of the virtual field of view by the operation of the operator. At this time, since the narrow field of view M3a after movement is contained in the X-ray detection region, the display of the X-ray image becomes a normal display as shown in FIG. 10A as an example.

FIG. 9C is a diagram illustrating the positional relationship between the narrow field of view M3 and the medium field of view M2 when the irradiation field is expanded from the narrow field of view M3 to the medium field of view M2. The operator selects the visual field size of the medium visual field M2, for example, by pressing the switch button of the input interface circuit 9. The field of view size setting function 10a sets the field of view size of the medium field of view M2 by the operation of the operator. At this time, the medium visual field M2 includes a region outside the X-ray detection region. Therefore, as illustrated in FIG. 10B, in the display window 42, the mesh image 43 representing the region outside the X-ray detection region is displayed together with the X-ray image.

In the above specific example, the center of the virtual field of view is always the center of the display window. As a method of clearly indicating the center of the virtual field of view, for example, there is a method of displaying the central axis 51 and the central axis 52 as shown in FIGS. 11A and 11B. At this time, the center of the virtual field of view is the intersection of the central axis 51 and the central axis 52.

FIG. 11A shows a display example when the visual field is within the X-ray detection region as in FIG. 7A and the like. Further, if the center of the virtual field of view is the center of the display window, the outer portion of the X-ray detection area does not necessarily have to be displayed. For example, FIG. 11B shows a display example when the region of interest is located at the end of the X-ray detection region as shown in FIG. 7C.

As described above, according to one embodiment, the X-ray diagnostic apparatus sets one of a plurality of visual field sizes for the X-ray irradiation field. Further, the X-ray diagnostic apparatus sets a virtual field of view having a set field of view size so as to extend beyond the X-ray detection area of the X-ray detector. Then, the X-ray diagnostic apparatus controls the X-ray movable diaphragm so as to irradiate the common area between the set virtual field of view and the X-ray detection area with X-rays. Therefore, since the X-ray diagnostic apparatus can include a region outside the X-ray detection region in the visual field, the region of interest is placed in the center of the displayed image even when the edge of the X-ray detection region is irradiated with X-rays. Can be positioned.

Further, according to one embodiment, since the X-ray diagnostic apparatus can set a virtual field of view by switching a plurality of field of view sizes, a region outside the X-ray detection area is included when the field of view size is expanded. Even if it is, the area of interest can be continuously displayed in the center of the displayed image.

Further, according to one embodiment, the X-ray diagnostic apparatus sets the virtual field of view so that the center of the virtual field of view is located in the X-ray detection region, so that it is possible to prevent erroneous setting of the virtual field of view.

Further, according to one embodiment, the X-ray diagnostic apparatus generates a display image corresponding to the virtual field of view so as to connect the X-ray image and the padding image showing the region outside the X-ray detection region. Therefore, since the X-ray diagnostic apparatus can include the region outside the X-ray detection region in the display image corresponding to the virtual visual field, the region of interest can be continuously displayed in the center of the display image. Further, the padding image is an image having a different form from the X-ray image. Therefore, the X-ray image and the padding image can be displayed separately.

Further, according to one embodiment, the X-ray diagnostic apparatus generates the padding image as a black-and-white two-gradation mesh image. The X-ray image is generated as an image showing the internal organs and bones of the subject by the polytone between white and black. Therefore, the X-ray image and the padding image can be clearly distinguished and displayed.

Further, according to one embodiment, the X-ray diagnostic apparatus generates a padding image showing a region outside the X-ray detection region using hue information, so that when a color display is used, the X-ray image and the X-ray image are generated. It can be clearly distinguished from the padding image and displayed.

The term "processor" used in the above description refers to, for example, a CPU, a GPU (Graphics Processing Unit), an integrated circuit for a specific application (Application Specific Integrated Circuit: ASIC), a programmable logic device (for example, a simple programmable logic device (eg, a simple programmable logic device)). It means a circuit such as a Simple Program Logic Device (SPLD), a composite programmable logic device (Comlex Programmable Logic Device: CPLD), and a field programmable gate array (Field Programmable Gate Array: FPGA).

The processor realizes various functions by reading and executing a program stored in a storage circuit. Instead of storing the program in the storage circuit, the program may be directly embedded in the circuit of the processor. In this case, the processor realizes various functions by reading and executing a program embedded in the circuit.

It should be noted that each processor of the present embodiment is not limited to the case where each processor is configured as a single circuit, and a plurality of independent circuits are combined to form one processor to realize various functions thereof. May be good. Further, a plurality of components may be integrated into one processor to realize the function.

The visual field size setting function, the virtual visual field setting function, and the aperture control function in one embodiment are examples of a visual field size setting unit, a virtual visual field setting unit, and an aperture control unit within the scope of claims. The image generation circuit and processing circuit in one embodiment are examples of an image generation unit and a generation unit within the scope of claims.

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

1 ... X-ray diagnostic device, 2 ... X-ray high voltage device, 3 ... X-ray source device, 3a ... X-ray tube, 3b ... X-ray movable throttle, 4 ... X-ray detector, 5 ... Support frame, 6 ... Heaven Board, 7 ... image generation circuit, 8 ... communication interface circuit, 9 ... input interface circuit, 10 ... control circuit, 11 ... processing circuit, 12 ... storage circuit, 13 ... display circuit, 20 ... aperture mechanism, 21a, 21b, 22a , 22b ... Aperture blade, 23 ... 1st central axis, 24 ... 2nd central axis, 30, 40, 50 ... Display, 31, 32, 34, 42, 53, 54 ... Display window, 33, 35, 43 ... Mesh image, 51, 52 ... Central axis, M1 ... Wide field, M2, M2a ... Medium field, M3, M3a ... Narrow field, N0 ... Normal field, ROI ... Area of interest, x1, x2a, x2b, xy, y1, y2a, y2b ... Movement direction.

Claims (8)

An X-ray movable diaphragm that limits the X-ray irradiation field generated from the X-ray tube,
A visual field size setting unit for setting the visual field size for the X-ray irradiation field, and a visual field size setting unit.
When at least a part of the virtual visual field having the visual field size is located outside the X-ray detection region for detecting the X-ray, the X is relative to the common region between the virtual visual field and the X-ray detection region. An aperture control unit that controls the X-ray movable aperture so that the line is irradiated , and
A display unit that displays an image including an X-ray image corresponding to the common area and a padding image corresponding to a region where the virtual field of view protrudes from the X-ray detection area as a display image corresponding to the virtual field of view.
X-ray diagnostic apparatus. A virtual field of view setting unit that enables the virtual field of view to be set at a position where at least a part of the virtual field of view having the field of view size protrudes from the X-ray detection region.
The X-ray diagnostic apparatus according to claim 1, further comprising. The virtual field of view setting unit sets the virtual field of view with the setting of the field of view size as an opportunity.
The X-ray diagnostic apparatus according to claim 2 . The field of view size setting unit is set from any one of a plurality of field of view sizes.
The X-ray diagnostic apparatus according to any one of claims 1 to 3 . The center of the virtual field of view is located within the X-ray detection region .
The X-ray diagnostic apparatus according to any one of claims 1 to 4. An image generating unit that generates the X-ray image based on the X-ray detected by the X-ray detection region, and an image generating unit.
It further includes a generation unit that generates an image obtained by connecting the X-ray image and the padding image as the display image .
The X-ray diagnostic apparatus according to any one of claims 1 to 5. The generation unit generates the padding image as a black-and-white two-gradation mesh image.
The X-ray diagnostic apparatus according to claim 6. The generation unit generates the padding image using hue information.
The X-ray diagnostic apparatus according to claim 6.

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