JP2020168145A - X-ray diagnostic apparatus - Google Patents

Abstract

To select an appropriate additional filter according to a target dose.SOLUTION: An X-ray diagnostic apparatus includes: an X-ray tube: an X-ray detector: a plurality of filters for attenuating an X-ray emitted from the X-ray tube; a filter drive unit for inserting at least one of the plurality of filters in a route from an X-ray focal point in the X-ray tube to the X-ray detector; and a filter selection unit for selecting a filter to be inserted into the route of the plurality of filters based on at least one of the size of a pixel in the X-ray detector, the size of a pixel in an X-ray image based on the output by the X-ray detector, and the size of an X-ray irradiation region, and information on the body thickness of a subject.SELECTED DRAWING: Figure 1

Description

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

The X-ray diagnostic apparatus is provided in the X-ray generating unit, and has an X-ray diaphragm that adjusts the size of the X-ray irradiation region (hereinafter, referred to as the visual field size). The X-ray diaphragm has a plurality of filters having different thicknesses (hereinafter, referred to as additional filters). The additional filter is also called a quality filter or a beam spectrogram filter. At least one of the additional filters is inserted in the path from the focal point of the X-ray tube to the X-ray detector and placed in front of the X-ray emission window at the X-ray generator. The additional filter inserted in the path adjusts the quality of the X-rays by reducing the soft lines of X-rays that pass through the additional filter. The additional filter inserted in the path includes the thickness of the subject (hereinafter referred to as body thickness) estimated by the conditions of X-ray irradiation by the X-ray tube (hereinafter referred to as X-ray conditions) and the like, and the radiation source. It is automatically selected based on the distance between image receiving surfaces (Source Image Distance: hereinafter referred to as SID).

On the other hand, when the size of each detection element of the FPD (Flat Panel Detector) provided in the X-ray detector (hereinafter referred to as the FPD element size) or the field size changes, the image quality of the X-ray image is ensured. The X-ray dose required for this (hereinafter referred to as the target dose) changes. If the additional filter is selected without considering the change in the target dose, the appropriate additional filter may not be selected.

Japanese Unexamined Patent Publication No. 2013-116184

The problem to be solved by the present invention is to select an appropriate additional filter according to the target dose.

The X-ray diagnostic apparatus according to the embodiment includes an X-ray tube that generates X-rays, an X-ray detector that detects X-rays emitted from the X-ray tube, and X-rays emitted from the X-ray tube. A filter drive unit that inserts at least one of the plurality of filters into the plurality of filters for damping and the path of the X-ray from the focus of the X-ray in the X-ray tube to the X-ray detector. And at least one of the size of the pixel in the X-ray detector, the size of the pixel in the X-ray image based on the output by the X-ray detector, and the size of the X-ray irradiation region, and the body thickness of the subject. A filter selection unit for selecting a filter to be inserted into the path from the plurality of filters based on the information regarding the above.

FIG. 1 is a diagram illustrating the configuration of the X-ray diagnostic apparatus according to the first embodiment. FIG. 2 is a flowchart illustrating a processing procedure of fluoroscopic execution processing by the X-ray diagnostic apparatus according to the first embodiment. FIG. 3 is a flowchart illustrating a processing procedure of imaging condition setting processing by the X-ray diagnostic apparatus according to the first embodiment. FIG. 4 is a flowchart illustrating a processing procedure of a filter selection process by the X-ray diagnostic apparatus according to the first embodiment. FIG. 5 is an example of a correspondence table showing the relationship between the maximum power, the exposure limit, the SID, and the body thickness used in the filter selection process by the X-ray diagnostic apparatus according to the first embodiment and the additional filter used. It is a figure which shows. FIG. 6 is an example of a correspondence table showing the relationship between the maximum power, the exposure limit, the SID, and the body thickness used in the filter selection process by the X-ray diagnostic apparatus according to the first embodiment and the additional filter used. It is a figure which shows. FIG. 7 is a flowchart illustrating the processing procedure of the filter selection process by the X-ray diagnostic apparatus according to the second embodiment. FIG. 8 is a flowchart illustrating the processing procedure of the filter selection process by the X-ray diagnostic apparatus according to the third embodiment. FIG. 9 is a flowchart illustrating the processing procedure of the filter selection process by the X-ray diagnostic apparatus according to the fourth embodiment. FIG. 10 is a flowchart illustrating a processing procedure of a filter selection process by the X-ray diagnostic apparatus according to the fifth embodiment. FIG. 11 is a flowchart illustrating the processing procedure of the filter selection process by the X-ray diagnostic apparatus according to the sixth embodiment. FIG. 12 is a flowchart illustrating a processing procedure of imaging condition setting processing by the X-ray diagnostic apparatus according to the seventh embodiment.

Hereinafter, embodiments of the X-ray diagnostic apparatus will be described in detail with reference to the drawings. In the following description, components having substantially the same function and configuration are designated by the same reference numerals, and duplicate explanations will be given only when necessary. The X-ray diagnostic apparatus according to the following embodiment may be, for example, a single modality apparatus or a composite modality apparatus such as an angio CT apparatus.

(First Embodiment)
FIG. 1 is a diagram showing a configuration example of the X-ray diagnostic apparatus 1 according to the first embodiment. As shown in FIG. 1, the X-ray diagnostic apparatus 1 includes an imaging apparatus 10, a sleeper apparatus 30, and a console apparatus 40. The photographing device 10 includes a high voltage generator 11, an X-ray generator 12, an X-ray detector 13, a C-arm 14, and a C-arm drive device 142.

The high voltage generator 11 generates a high voltage applied between the anode and the cathode in order to accelerate thermions generated from the cathode of the X-ray tube and outputs the high voltage to the X-ray tube.

The X-ray generator 12 includes an X-ray tube that irradiates the subject P with X-rays, a plurality of filters having a function of attenuating or reducing the irradiation X-ray dose (hereinafter referred to as an additional filter), and an X-ray diaphragm. Is equipped with.

The X-ray tube is a vacuum tube that generates X-rays. The X-ray tube includes a tube, a filament (cathode) provided on the tube, and a tungsten anode. The X-ray tube accelerates thermions emitted from the filament by a high voltage. The X-ray tube generates X-rays by colliding the accelerating electrons with the tungsten anode.

In the present embodiment, two types of filaments having different sizes of the generated X-ray focal points (effective focal points) (hereinafter, referred to as focal points) are provided. A filament to be used is selected from the two filaments according to the input by the operator on the input interface 43 described later or the setting by the processing circuit 44 described later, and the filament used by driving a drive device (not shown). Is switched. Then, by switching the filament used, the focal size is switched between the small focus and the medium focus. The medium focus has a larger focal size than the small focus. The small focus is, for example, a value in the range of 0.2 to 0.4 mm. The midfocus is, for example, a value in the range of 0.5 to 0.7 mm. The small focus is an example of the first focus size. The midfocal is an example of a second focal size.

In the present embodiment, two types of focal sizes, a small focus and a medium focus, can be set as the focus size settings, but three or more focal sizes may be set. In this case, a number of filaments is provided corresponding to the number of focal sizes that can be set.

The additional filter is composed of a metal plate such as copper or aluminum. By inserting the additional filter between the X-ray tube and the X-ray diaphragm, the long wavelength component (soft X-ray) of the continuous spectrum X-ray generated by the X-ray generating unit 12 is adjusted according to the thickness of the additional filter. To remove. The thickness of the additional filter is, for example, a value in the range of 0.1 to 5 mm. The additional filter is also called an X-ray filter, a filter plate, a beam filter, a quality filter, or a beam spectrum filter. The additional filter cures the quality of the X-rays generated by the X-ray generator 12 by removing the long wavelength component according to the thickness. The additional filter can also remove X-ray energy components that are unnecessary for X-ray diagnosis. As a result, the additional filter adjusts the quality of the X-rays generated by the X-ray generating unit 12.

In this embodiment, four additional filters (filter A to filter D) are provided. The filters A to D have different thicknesses. Therefore, the filters A to D have different soft X-ray removal rates (hereinafter referred to as X-ray reduction rates). A thick additional filter (a thick additional filter) has a larger X-ray reduction rate than a thin additional filter (a thin additional filter). The thickness of the filter A is larger than the thickness of the filter B, the thickness of the filter B is larger than the thickness of the filter C, and the thickness of the filter C is larger than the thickness of the filter D. Therefore, the X-ray reduction rate of the filter A is larger than the X-ray reduction rate of the filter B, the X-ray reduction rate of the filter B is larger than the X-ray reduction rate of the filter C, and the X-ray reduction rate of the filter C is the filter. It is larger than the X-ray reduction rate of D.

The drive device selects an additional filter selected from a plurality of additional filters according to the input by the operator at the input interface 43 described later or the setting by the processing circuit 44 described later, of the X-ray tube and the X-ray diaphragm. Insert in between. Further, the thickness of the additional filter is adjusted by switching the additional filter inserted between the X-ray tube and the X-ray diaphragm. That is, the drive device inserts at least one of the plurality of additional filters into the path from the focal point of the X-ray tube to the X-ray detector 13. The drive device is an example of a filter drive unit.

The X-ray diaphragm is located between the X-ray tube and the X-ray detector 13, and is composed of a lead plate as a metal plate. The X-ray diaphragm blocks the X-rays outside the opening region, thereby narrowing the X-rays generated by the X-ray tube so that only the region of interest of the subject P is irradiated, thereby irradiating the X-ray irradiation region (X). Adjust the size of the X-ray irradiation field (hereinafter referred to as the field size). For example, an X-ray diaphragm has four diaphragm blades, and by sliding these diaphragm blades, the area where X-rays are shielded can be adjusted to an arbitrary size, thereby adjusting the visual field size. The diaphragm blades of the X-ray diaphragm are driven by a drive device (not shown) according to the region of interest input by the operator from the input interface 43.

The X-ray detector 13 detects X-rays emitted from an X-ray tube and transmitted through the subject P. As such an X-ray detector 13, one that directly converts X-rays into electric charges and one that converts X-rays into light and then converts them into electric charges can be used. Here, the former will be described as an example, but the latter. It doesn't matter. That is, the X-ray detector 13 is, for example, a flat FPD (Flat Panel Detector) that converts X-rays transmitted through the subject P into electric charges and stores them, and a drive for reading out the electric charges accumulated in the FPD. It is equipped with a gate driver that generates pulses. The size of the FPD is, for example, a value in the range of 8 to 16 inches. The FPD is configured by arranging minute detection elements two-dimensionally in the column direction and the line direction. Each detection element determines a photoelectric film that senses X-rays and generates an electric charge according to the incident X-ray dose, a charge storage capacitor that stores the electric charge generated in the photoelectric film, and a charge accumulated in the charge storage capacitor. It is equipped with a TFT (thin film) that outputs at the timing of. The accumulated charges are sequentially read out by the drive pulse supplied by the gate driver. The size (hereinafter, referred to as FPD element size) of each detection element of the FPD (hereinafter, referred to as an FPD detection element) is, for example, a value in the range of 130 to 200 μm. However, the FPD element size is not limited to this example, and may be a minute size such as 76 μm square.

In the present embodiment, the X-ray detector 13 is provided with two types of FPDs (FPD1 to FPD2). FPD1 and FPD2 include the number of detection elements (hereinafter referred to as the number of FPD elements), the size of the FPD element, the resolution, and the X-ray dose required to ensure the image quality of the X-ray image (hereinafter referred to as the target dose). And the corresponding imaging modes are different. In the present embodiment, the FPD element size corresponds to the size of one pixel of the FPD (hereinafter, referred to as the FPD pixel size). The FPD pixel size is an example of the pixel size in the X-ray detector 13. The FPD to be used is selected from the two FPDs according to the input by the operator on the input interface 43 described later or the setting of the imaging mode by the processing circuit 44 described later, and by driving a drive device (not shown). The FPD used is switched. By switching the FPD used, the number of FPD elements, the FPD element size, the FPD pixel size, the resolution, and the target dose can be switched. The size of FPD1 and the size of FPD2 may be different or the same. Further, FPD1 and FPD2 may share one scintillator.

FPD1 corresponds to the imaging mode of the normal mode. The FPD2 corresponds to an imaging mode in a high-definition mode having a higher resolution than the normal mode. The FPD2 has a larger number of FPD elements and a smaller FPD pixel size and FPD element size than the FPD1. Therefore, FPD2 has a larger target dose than FPD1. The normal mode is an example of the first imaging mode. The high-definition mode is an example of the second imaging mode. The FPD pixel size of the FPD1 is an example of the first size of the FPD pixel size. The FPD pixel size of the FPD2 is an example of a second size of the FPD pixel size. The FPD element size of the FPD1 is an example of the first size of the FPD element size. The FPD element size of the FPD2 is an example of a second size of the FPD element size.

The C-arm 14 holds the X-ray generator 12 and the X-ray detector 13 so as to face each other with the subject P and the top plate 33 interposed therebetween, so that X-ray imaging of the subject P on the top plate 33 can be performed. It has a configuration that can be performed. The C-arm 14 is slidable and rotatably supported around each of the plurality of rotation axes. The C-arm 14 is provided with a plurality of power sources for realizing operations related to sliding and rotation at appropriate locations. These power sources constitute a C-arm drive device 142. The C-arm drive device 142 reads a drive signal from the drive control function 444 and causes the C-arm 14 to slide, rotate, and linearly move.

The sleeper device 30 is a device on which the subject P is placed and moved, and includes a base 31, a sleeper drive device 32, a top plate 33, and a support frame 34.

The base 31 is a housing that is installed on the floor and supports the support frame 34 so as to be movable in the vertical direction (Z direction).

The sleeper drive device 32 is a motor or actuator that is housed in the housing of the sleeper device 30 and moves the top plate 33 on which the subject P is placed in the longitudinal direction (Y direction) of the top plate 33. The bed drive device 32 reads the drive signal from the drive control function 444 and moves the top plate 33 in the horizontal direction or the vertical direction with respect to the floor surface. When the C arm 14 or the top plate 33 moves, the positional relationship of the imaging axis with respect to the subject P changes. In addition to the top plate 33, the sleeper drive device 32 may move the support frame 34 in the longitudinal direction of the top plate 33.

The top plate 33 is provided on the upper surface of the support frame 34, and is a plate on which the subject P is placed.

The support frame 34 is provided on the upper part of the base 31, and slidably supports the top plate 33 along the longitudinal direction thereof.

In the sleeper device 30, the top plate 33 may be movable with respect to the support frame 34, or the top plate 33 and the support frame 34 may be movable with respect to the base 31. Good.

The console device 40 includes a memory 41, a display 42, an input interface 43, and a processing circuit 44. Although the console device 40 will be described as a separate body from the photographing device 10, the photographing device 10 may include a part of each component of the console device 40 or the console device 40. The console device 40 corresponds to, for example, a medical image processing device.

Hereinafter, the console device 40 will be described as executing a plurality of functions on a single console, but a plurality of functions may be executed by different consoles. For example, the functions of the processing circuit 44, such as the image generation function 446 described later, may be distributed and mounted in different console devices.

The memory 41 is a storage device such as an HDD (Hard Disk Drive), an SSD (Solid State Drive), or an integrated circuit that stores various information. In addition to the HDD and SSD, the memory 41 may be a portable storage medium such as a CD (Compact Disc), a DVD (Digital Versaille Disc), or a flash memory. The memory 41 may be a drive device that reads and writes various information to and from a semiconductor memory element such as a flash memory or a RAM (Random Access Memory). Further, the storage area of the memory 41 may be in the X-ray diagnostic apparatus 1 or in an external storage device connected by a network.

The memory 41 stores, for example, an X-ray image, a program executed by the processing circuit 44, various data used for processing the processing circuit 44, and the like. The memory 41 is an example of a storage unit.

The display 42 displays various information. For example, the display 42 outputs a medical image (X-ray image) generated by the processing circuit 44, a GUI (Graphical User Interface) for receiving various operations from the operator, and the like. For example, the display 42 is a liquid crystal display or a CRT (Cathode Ray Tube) display. The display 42 is an example of a display unit. Further, the display 42 may be provided in the photographing device 10. Further, the display 42 may be a desktop type, or may be composed of a tablet terminal or the like capable of wireless communication with the console device 40 main body.

The input interface 43 receives various input operations from the operator, converts the received input operations into electric signals, and outputs the received input operations to the processing circuit 44. For example, the input interface 43 receives subject information, imaging conditions, input of various command signals, and the like from the operator. For example, the input interface 43 can be used to move the C-arm 14 to a trackball, a mouse or keyboard, a trackball, a switch, a button, a joystick, or an operation surface for setting a region of interest (ROI), performing fluoroscopy, and the like. It is realized by a touch pad that performs input operations by touching, a touch panel display in which a display screen and a touch pad are integrated, a foot switch, and the like. Further, the input interface 43 is an example of an input unit and an operation unit. Further, the input interface 43 may be provided in the photographing device 10. Further, the input interface 43 may be composed of a tablet terminal or the like capable of wireless communication with the console device 40 main body. The input interface 43 is not limited to the one provided with physical operating parts such as a mouse and a keyboard. For example, an example of the input interface 43 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 processing circuit 44. .. The input interface 43 is an example of an operation unit for instructing imaging of a moving image using an X-ray tube and an X-ray detector 13.

The processing circuit 44 controls the operation of the entire X-ray diagnostic apparatus 1. The processing circuit 44 calls and executes a program in the memory 41 to call and execute a system control function 441, an imaging condition setting function 442, a filter selection function 443, a drive control function 444, an X-ray control function 445, an image generation function 446, and a display. It is a processor that executes the control function 447.

In FIG. 1, a single processing circuit 44 uses a system control function 441, an imaging condition setting function 442, a filter selection function 443, a drive control function 444, an X-ray control function 445, an image generation function 446, and a display control function. Although 447 has been described as being realized, a processing circuit may be formed by combining a plurality of independent processors, and each function may be realized by executing a program by each processor. Further, the system control function 441, the image pickup condition setting function 442, the filter selection function 443, the drive control function 444, the X-ray control function 445, the image generation function 446, and the display control function 447 are the system control circuit, the image pickup condition setting circuit, respectively. It may be called a filter selection circuit, a drive control circuit, an X-ray control circuit, an image processing circuit, and a display control circuit, or may be implemented as individual hardware circuits.

The word "processor" used in the above description is, for example, a CPU (Central Processing Unit), a GPU (Graphics Processing Unit), or an ASIC, a programmable logic device (for example, a Simple Programmable Logic Device (SPLD)). , Complex Programmable Logic Device (CPLD), and Field Programmable Gate Array (FPGA), etc. The processor functions by reading and executing the program stored in the storage circuit. In addition, instead of storing the program in the storage circuit, the program may be configured to be directly embedded in the circuit of the processor. In this case, the processor reads and executes the program incorporated in the circuit. 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, and the function is realized. Further, a plurality of components in FIG. 1 may be integrated into one processor to realize the function.

The processing circuit 44 controls each of the plurality of components in the X-ray diagnostic apparatus 1 based on the input operation received from the operator via the input interface 43 by the system control function 441. For example, the processing circuit 44 controls various components in the photographing apparatus 10 according to the imaging conditions. The processing circuit 44 that realizes the system control function 441 is an example of the system control unit.

The processing circuit 44 sets imaging conditions (hereinafter referred to as imaging conditions) by the imaging condition setting function 442. Clairvoyance is an example of moving image imaging. The processing circuit 44 that realizes the imaging condition setting function 442 is an example of the imaging condition setting unit.

The imaging conditions include the conditions for X-ray irradiation by an X-ray tube (hereinafter referred to as X-ray conditions), the magnification of AGC (Auto Gain Control) (hereinafter referred to as AGC magnification), and information on the additional filter used (hereinafter referred to as "AGC magnification"). , Filter specific information), detector spatial resolution, resolution, size of 1 pixel (1 pixel) in X-ray image (hereinafter referred to as pixel size), FPD pixel size, FPD element size, number of FPD elements, multiple The number of FPD detection elements (hereinafter referred to as the number of binning) corresponding to one pixel of the FPD in the control method (hereinafter referred to as binning control) for treating the FPD detection element of the above as one pixel of the FPD, and at least one of the imaging modes. Includes one. The filter specific information includes at least one of the type of additional filter used, the thickness of the additional filter used, and the like. The imaging condition may be referred to as a fluoroscopic condition. The imaging condition setting function 442 is an example of an X-ray condition determining unit that determines an X-ray condition.

The X-ray conditions are, for example, tube current, tube voltage, focal size, pulse width, pulse rate (number of pulses per unit time), field size, distance between radiation source image receiving surfaces (Source Image Distance): hereinafter referred to as SID. ), And at least one of the duration of X-ray exposure and the like.

The processing circuit 44 uses the filter selection function 443 to determine the maximum output of X-rays (hereinafter referred to as the maximum power) defined by the FPD element size in fluoroscopy with the number of fluoroscopy N and the rating of the tube of the X-ray tube. , X of a plurality of additional filters based on the upper limit of the X-ray incident dose to the subject per unit time (hereinafter referred to as the exposure limit) and the thickness of the subject (hereinafter referred to as the body thickness). Select an additional filter to insert in the path from the focal point of the tube to the X-ray detector 13. The maximum power may be referred to as the output upper limit of the X-ray tube. Body thickness is an example of subject information. The filter selection function 443 is an example of a filter selection unit.

The processing circuit 44 controls the C-arm drive device 142 and the sleeper drive device 32 by the drive control function 444, for example, based on the information regarding the drive of the C-arm 14 and the top plate 33 input from the input interface 43. The processing circuit 44 that realizes the drive control function 444 is an example of the drive control unit.

The processing circuit 44 reads information from, for example, the system control function 441 by the X-ray control function 445, and X-ray conditions such as tube current, tube voltage, focus size, irradiation time, and pulse width in the high voltage generator 11. To control. The X-ray control function 445 is a function of selecting a filament to be used from a plurality of filaments provided in the tube of the X-ray tube based on the size of the X-ray focal point determined by the imaging condition setting function 442. May include. The processing circuit 44 that realizes the X-ray control function 445 is an example of the X-ray control unit.

The processing circuit 44 generates an X-ray image based on, for example, the data output from the X-ray detector 13 by the image generation function 446. At this time, the processing circuit 44 performs AGC. AGC is a control for adjusting the brightness of the generated X-ray image in order to keep the brightness of the generated X-ray image constant. Supplementally, AGC is a digital gain applied to the entire image in order to secure the brightness of the X-ray image when the radiation dose to the detector cannot be secured due to the exposure limit (Dose Limit) or the limit of the tube output. .. The AGC magnification is the ratio of the brightness of the adjusted X-ray image to the X-ray image before adjustment by AGC. The processing circuit 44 may perform various composition processing, subtraction processing, and the like on the generated X-ray image. The X-ray image is an example of medical data. The processing circuit 44 that realizes the image generation function 446 is an example of the image generation unit.

Further, the processing circuit 44 switches the FPD to be used according to the selected imaging mode by the X-ray control function 445 and the image generation function 446. By switching the FPD to be used, the FPD pixel size and the FPD element size change. For example, when the normal mode is selected as the imaging mode, the processing circuit 44 switches the FPD to be used to the FPD 1, controls the X-ray conditions corresponding to the normal mode, and generates an X-ray image. For example, when the high-definition mode is selected as the imaging mode, the processing circuit 44 switches the FPD to be used to the FPD2, controls the X-ray conditions corresponding to the high-definition mode, and generates an X-ray image.

The processing circuit 44 reads, for example, a signal from the system control function 441 by the display control function 447, acquires a desired X-ray image from the memory 41, and displays it on the display 42. The processing circuit 44 that realizes the display control function 447 is an example of the display control unit.

Next, the operation of the fluoroscopic execution process executed by the X-ray diagnostic apparatus 1 will be described. The fluoroscopy execution process is a process of performing fluoroscopy of a subject in response to an operation on the input interface 43 in an examination.

The processing procedure in the fluoroscopic execution processing described below is only an example, and each processing can be changed as appropriate as possible. Further, with respect to the processing procedure described below, steps can be omitted, replaced, and added as appropriate according to the embodiment.

FIG. 2 is a flowchart showing an example of the procedure of the fluoroscopic execution process according to the present embodiment. The processing circuit 44 starts the fluoroscopic execution process based on, for example, an instruction to start the inspection being input in the input interface 43.

(Perspective execution processing)
(Step S101)
The processing circuit 44 executes the imaging condition setting function 442. The processing circuit 44 uses the imaging condition setting function 442 to perform processing for setting imaging conditions in fluoroscopy to be executed next (hereinafter, referred to as imaging condition setting processing). Details of the imaging condition setting process will be described later.

(Step S102)
The processing circuit 44 determines whether or not an instruction indicating that the inspection of the subject is to be completed has been input. At this time, the processing circuit 44 determines whether or not the instruction to end the test has been input by detecting, for example, the input of the instruction to end the test of the subject in the input interface 43. When the instruction to end the inspection is input (step S102-Yes), the processing circuit 44 ends the fluoroscopic execution process.

If no instruction to end the inspection is input (step S102-No), the process proceeds to step S103.

(Step S103)
The processing circuit 44 determines whether or not an instruction for executing fluoroscopy has been input in response to the operation of the input interface 43 by the operator. At this time, the processing circuit 44 determines whether or not an instruction for executing fluoroscopy has been input by detecting, for example, whether or not an operation is being performed on the foot switch. When an instruction to execute (start) fluoroscopy is input (step S103-Yes), the process proceeds to step S104. If no instruction to execute (start) fluoroscopy is input (step S103-No), the process returns to step S102, and the processing circuit 44 inputs an instruction to end the inspection or executes (starts) fluoroscopy. Wait until the instruction to be entered is entered.

(Step S104)
The processing circuit 44 executes fluoroscopy using the photographing device 10 by executing the system control function 441, the drive control function 444, the X-ray control function 445, and the image generation function 446.

During the execution of one fluoroscopy, the processing circuit 44 generates a plurality of X-ray images that are frames in chronological order by the image generation function 446, and the X-ray image generated by the image generation function 446 is generated. Store in memory 41. Then, the processing circuit 44 causes the display 42 to display the X-ray moving image generated by the plurality of X-ray images generated by the display control function 447. At this time, the processing circuit 44 executes the AGC by the image generation function 446.

Further, the processing circuit 44 is controlled by the system control function 441 and the X-ray control function 445 to set the X-ray condition in the subsequent frame based on the output of the X-ray detector 13 in the previous frame during execution of fluoroscopy. I do. That is, the processing circuit 44 performs feedback control for changing the X-ray condition and the like based on the change in the subject condition during the execution of one fluoroscopy. For example, in the feedback control, when the processing circuit 44 changes the body thickness or the structure of the internal tissue of the subject by the operation of moving the top plate 33 on which the subject is placed during the execution of one fluoroscopy. , The tube voltage, tube so that the brightness, contrast, etc. of the X-ray image generated in the previous frame are detected and the brightness, contrast, etc. of the X-ray image displayed in the subsequent frame satisfy the predetermined conditions. Control at least one of current, pulse width, and AGC magnification. With feedback control, the appropriate tube voltage, tube current, pulse width, and AGC magnification are selected even if the subject conditions change during one fluoroscopy. Therefore, at the end of fluoroscopy, at least one of the tube voltage, tube current, pulse width, and AGC magnification is in a state of being appropriately controlled in response to changes in subject conditions. In addition, the X-ray image finally generated in one fluoroscopy is in a state in which brightness, contrast, and the like are adjusted so as to satisfy predetermined conditions.

(Step S105)
The processing circuit 44 determines whether or not an instruction to end fluoroscopy has been input. At this time, the processing circuit 44 determines whether or not an instruction to end fluoroscopy has been input by detecting, for example, whether or not an operation is being performed by the operator on the foot switch. When an instruction to end fluoroscopy is input (step S105-Yes), the process proceeds to step S106. The processing circuit 44 continues the execution of fluoroscopy by the process of step S104 until an instruction to end fluoroscopy is input.

(Step S106)
The processing circuit 44 terminates fluoroscopy by X-ray imaging by executing the system control function 441, the drive control function 444, the X-ray control function 445, and the image generation function 446.
When the fluoroscopy by X-ray photography is completed, the process returns to step S101.

The processing circuit 44 sets the imaging conditions for the next fluoroscopy by executing the imaging condition setting process based on the completion of fluoroscopy by X-ray imaging. Specifically, the processing circuit 44 determines the size of the X-ray focal point in the second moving image imaging based on the completion of the first moving image imaging, and the second moving image imaging is completed. Based on this, the magnitude of the X-ray focus in the third moving image imaging is determined. Further, the processing circuit 44 determines whether or not an instruction indicating that the inspection is terminated by the processing of step S102 is input after setting the imaging conditions for fluoroscopy to be executed next by the processing of S101. Therefore, by completing the examination, the imaging conditions for the next fluoroscopy are set even if the next fluoroscopy is not executed.

As described above, in the fluoroscopy execution process, the processing circuit 44 starts fluoroscopy when an instruction to execute fluoroscopy is input in the input interface 43. The processing circuit 44 ends fluoroscopy when the instruction to execute fluoroscopy at the input interface 43 is released. Then, when the instruction to execute fluoroscopy is input again in the input interface 43, the processing circuit 44 executes the next fluoroscopy. During the execution of one fluoroscopy, the processing circuit 44 controls the imaging conditions so that the image quality of the X-ray image is appropriately ensured based on the change in the subject conditions.

(Imaging condition setting process)
Next, the operation of the imaging condition setting process executed by the X-ray diagnostic apparatus 1 will be described. The processing procedure in the imaging condition setting process described below is only an example, and each process can be changed as appropriate as possible. Further, with respect to the processing procedure described below, steps can be omitted, replaced, and added as appropriate according to the embodiment. FIG. 3 is a flowchart showing an example of the procedure of the imaging condition setting process according to the present embodiment, and corresponds to the imaging condition setting process of step S101 shown in FIG.

(Step S111)
The processing circuit 44 acquires a number (hereinafter, referred to as the number of fluoroscopy) indicating the number of fluoroscopy after the start of the inspection for the next fluoroscopy to be executed. The processing circuit 44 determines, for example, the number of times of fluoroscopy of the next fluoroscopy by acquiring the number of times of fluoroscopy performed so far in the inspection. For example, if fluoroscopy has not been performed so far after the start of the examination, the processing circuit 44 determines that the next fluoroscopy is the first fluoroscopy after the start of the examination, and determines the number of fluoroscopy to 1. Further, if one fluoroscopy has been performed after the start of the examination, the processing circuit 44 determines that the next fluoroscopy is the second fluoroscopy after the start of the examination, and determines the number of fluoroscopy to 2. .. Hereinafter, as an example, processing when the number of times of fluoroscopy is N will be described.

(Step S112)
The processing circuit 44 determines whether or not the number of fluoroscopy N of the next fluoroscopy is 1. By determining whether or not the number of fluoroscopy N of the next fluoroscopy is 1, the processing circuit 44 determines whether the fluoroscopy to be executed next is the fluoroscopy performed for the first time after the start of the examination, or after the start of the examination. Judge whether it is fluoroscopy after the second time. When the number of fluoroscopy N is 1 (step S112-Yes), it is determined that the fluoroscopy to be executed next is the first fluoroscopy after the start of the examination, and the process proceeds to step S113. When the number of fluoroscopy N is not 1 (step S112-Yes), that is, when the number of fluoroscopy N is 2 or more, it is determined that the next fluoroscopy to be performed is the second or subsequent fluoroscopy after the start of the examination, and the process is performed. The process proceeds to step S114.

(Step S113)
The processing circuit 44 uses the imaging condition setting function 442 and the filter selection function 443 to set the imaging conditions for fluoroscopy with the number of fluoroscopy 1 as default conditions. At this time, the processing circuit 44 sets the focal size to a small focus by, for example, the imaging condition setting function 442, and determines the additional filter to be used in the filter D by the filter selection function 443. Then, the processing circuit 44 acquires the default imaging conditions corresponding to the small focus and the filter D from the memory 41 by the imaging condition setting function 442, and obtains the acquired imaging conditions as the imaging conditions in fluoroscopy with the number of fluoroscopy N, that is, It is set as an imaging condition in the next fluoroscopy. Then, the processing circuit 44 ends the imaging condition setting process, and the process proceeds to step S103.

(Step S114)
When the number of fluoroscopy N is 2 or more, the processing circuit 44 executes a process of selecting an additional filter to be used in fluoroscopy of the number of fluoroscopy N (hereinafter, referred to as a filter selection process) by the filter selection function 443.

(Step S115)
The processing circuit 44 acquires the imaging conditions corresponding to the additional filter determined by the processing of step S114 from the memory 41, and obtains the acquired imaging conditions as the imaging conditions in fluoroscopy with the number of fluoroscopy N, that is, the fluoroscopy to be executed next. It is set as the imaging condition in. Then, the processing circuit 44 ends the imaging condition setting process, and the process proceeds to step S103.

(Filter selection process)
Hereinafter, the operation of the filter selection process executed by the X-ray diagnostic apparatus 1 will be described. The processing procedure in the filter selection process described below is only an example, and each process can be changed as appropriate as possible. Further, with respect to the processing procedure described below, steps can be omitted, replaced, and added as appropriate according to the embodiment. FIG. 4 is a flowchart showing an example of the procedure of the filter selection process according to the present embodiment, and corresponds to the filter selection process of step S114 shown in FIG.

(Step S121)
The processing circuit 44 acquires the imaging conditions for fluoroscopy with the number of fluoroscopy N-1. The processing circuit 44 acquires, for example, the imaging conditions for fluoroscopy having the number of fluoroscopy N-1 stored in the memory 41 by reading out the imaging conditions for fluoroscopy. The processing circuit 44 acquires the imaging conditions for fluoroscopy performed immediately before the start of the examination by acquiring the imaging conditions for fluoroscopy with the number of fluoroscopy N-1. The processing circuit 44 acquires, for example, the focal size, filter specific information, tube voltage, tube current, pulse width, and AGC magnification as imaging conditions in fluoroscopy with the number of fluoroscopy N-1. As described above, during fluoroscopy, feedback control is performed to change the X-ray conditions and the like based on changes in subject conditions, and at the end of fluoroscopy, the tube voltage, tube current, pulse width, and AGC magnification are measured. At least one of them is in a state of being appropriately controlled according to a change in subject conditions. Therefore, by acquiring the imaging conditions in fluoroscopy executed immediately before, it is possible to acquire the imaging conditions appropriately controlled according to the change in the subject conditions. It should be noted that the arithmetic processing based on the X-ray image generated in the fluoroscopy executed immediately before is used to calculate the imaging conditions that are more appropriately controlled according to the change in the subject conditions, and the calculated imaging conditions are executed immediately before. It may be acquired as an imaging condition in fluoroscopy.

(Step S122)
The processing circuit 44 determines the body thickness in fluoroscopy with the number of fluoroscopy N-1 based on the imaging conditions in fluoroscopy with the number of fluoroscopy N-1. Specifically, the processing circuit 44 has a correspondence table stored in advance in the memory 41 based on the filter specific information, the tube voltage, the tube current, the pulse width, and the AGC magnification at the end of the fluoroscopy of the number of fluoroscopy N-1. Alternatively, an estimated value of body thickness in fluoroscopy with the number of fluoroscopy N-1 is calculated by a known calculation method. It is assumed that the body thickness at the end of fluoroscopy with the number of fluoroscopy N-1 is the same as the body thickness at the start of fluoroscopy with the number of fluoroscopy N-1. The body thickness at the end of fluoroscopy with the number of fluoroscopy N-1 is an estimated value of the body thickness of the subject calculated based on the X-ray condition appropriately adjusted according to the change in the subject condition by the feedback control described above. Is. The processing circuit 44 may acquire the body thickness by, for example, detecting an operation input for inputting the body thickness at the input interface 43. The estimated body thickness of the subject calculated based on the X-ray conditions adjusted by the feedback control is an example of information on the body thickness.

(Step S123)
The processing circuit 44 acquires the imaging mode, maximum power, exposure limit, body thickness, and SID in fluoroscopy with the number of fluoroscopy times N. At this time, the processing circuit 44 reads, for example, the imaging mode, the maximum power, the exposure limit, the body thickness, and the SID in fluoroscopy with the number of fluoroscopy N from the memory 41.

Further, the processing circuit 44 acquires the FPD element size in fluoroscopy with the number of fluoroscopy N, for example, by detecting the operation input on the display 42 used as the input interface 43. For example, when the imaging mode is the normal mode, the processing circuit 44 acquires the element size of the detection element of the FPD1 as the FPD element size in fluoroscopy with the number of fluoroscopy N. When the imaging mode is the high-definition mode, the processing circuit 44 acquires the element size of the detection element of the FPD2 as the FPD element size in fluoroscopy with the number of fluoroscopy N.

(Step S124)
The processing circuit 44 reads out the corresponding correspondence table from the plurality of correspondence tables (tables) stored in the memory 41 based on the FPD element size in the fluoroscopy of the fluoroscopic number N acquired in the process of step S123.

5 and 6 are diagrams showing an example of a correspondence table (table) used in the process of determining the additional filter in step S124. FIG. 5 is an example of a correspondence table used when the imaging mode is the normal mode. FIG. 6 is an example of a correspondence table used when the imaging mode is the high-definition mode. Each of FIGS. 5 and 6 shows the relationship between the maximum power, the exposure limit, the SID, and the body thickness and the additional filter used. For example, FIG. 5 shows a relationship in which a thinner additional filter is used as the exposure limit, SID, and body thickness are larger at the same maximum power (however, additional filter thickness: A> B> C> D). This relationship is noticeable when the body thickness exceeds 25 cm. FIG. 6 shows a similar relationship. The processing circuit 44 reads out the correspondence table of FIG. 5 when the imaging mode is the normal mode, that is, when the FPD element size in fluoroscopy with the number of fluoroscopy N is the element size of the detection element of FPD1. The processing circuit 44 reads out the correspondence table of FIG. 6 when the imaging mode is the high resolution mode, that is, when the FPD element size in fluoroscopy with the number of fluoroscopy N is the element size of the detection element of FPD2.

(Step S125)
The processing circuit 44 selects the number of fluoroscopy N from the filters A to D based on the correspondence table read in the process of step S124 and the maximum power, exposure limit, SID, and body thickness in fluoroscopy of the number of fluoroscopy N. Determine the additional filter used for fluoroscopy. The processing circuit 44 stores the filter specific information regarding the determined additional filter in the memory 41.

In the processing of steps S124 and S125, the processing circuit 44 selects an additional filter having a thickness equal to or larger than the thickness of the additional filter selected when the FPD element size is large and the FPD element size is small. For example, when the FPD element size is the first size, the processing circuit 44 selects the first filter having the first thickness, and the FPD element size is larger than the first size. If, a second filter having a second thickness greater than the first thickness is selected. Supplementally, in this example, whether or not the FPD element size is large corresponds to whether or not the FPD element size is the second size of the first size and the second size. In other words, in this example, the case where the FPD element size is large corresponds to the case where the FPD element size is the second size of the first size and the second size. However, not limited to this, the FPD element size is large depending on whether or not the FPD element size is equal to or larger than the reference value by using the reference value of the size between the first size and the second size. It may be determined whether or not. The same applies to whether or not the FPD pixel size is large. Further, when the FPD element size (FPD pixel size) is small, similarly, it corresponds to the case where the FPD element size is the first size among the first size and the second size. Not limited to this, the case where the FPD element size (FPD pixel size) is small may be determined by using the magnitude relationship with the reference value.

Further, the processing circuit 44 may acquire the FPD pixel size based on the FPD element size. In this case, the processing circuit 44 selects an additional filter having a thickness equal to or larger than the thickness of the additional filter selected when the FPD pixel size is large and the FPD pixel size is small. For example, when the FPD pixel size is the first size, the processing circuit 44 selects the first filter having the first thickness, and the FPD pixel size is larger than the first size. If, a second filter having a second thickness greater than the first thickness is selected.

Further, the processing circuit 44 selects an additional filter having a thickness equal to or larger than the thickness of the additional filter selected when the image pickup mode is the high-definition mode when the image pickup mode is the normal mode. Further, the processing circuit 44 selects an additional filter having a thickness equal to or larger than the thickness of the additional filter selected when the maximum power is large and the maximum power is small. Further, the processing circuit 44 selects an additional filter having a thickness equal to or larger than the thickness of the additional filter selected when the exposure limit is small or when the exposure limit is large. Further, the processing circuit 44 selects an additional filter having a thickness equal to or larger than the thickness of the additional filter selected when the SID is small or the SID is large. Further, the processing circuit 44 selects an additional filter having a thickness equal to or larger than the thickness of the additional filter selected when the body thickness is small or when the body thickness is large.

Hereinafter, the effect of the X-ray diagnostic apparatus 1 according to the present embodiment will be described.

The X-ray diagnostic apparatus 1 of the present embodiment is an X-ray detector from the focal point of an X-ray tube among a plurality of filters based on the pixel size in the X-ray detector 13 and information on the body thickness of the subject. Select the filter to be inserted in the X-ray path to 13.

Specifically, the X-ray diagnostic apparatus 1 of the present embodiment provides an additional filter to be inserted into the path from the focal point of the X-ray tube to the X-ray detector 13 based on the FPD element size and the body thickness in the next fluoroscopy. Select from multiple additional filters. Further, the X-ray diagnostic apparatus 1 of the present embodiment includes a plurality of additional filters to be inserted into the path from the focal point of the X-ray tube to the X-ray detector 13 based on the FPD pixel size and the body thickness in the next fluoroscopy. Select from the additional filters of.

Further, the X-ray diagnostic apparatus 1 of the present embodiment acquires the size of the pixels in the X-ray detector 13 based on the size of the detection element, and the size of the pixels in the X-ray detector 13 and the body of the subject. A filter having a thickness greater than or equal to the thickness of the filter selected when the size of the pixels in the X-ray detector 13 is large and the size of the pixels in the X-ray detector 13 is small, based on the information on the thickness. , Select as a filter to be inserted in the X-ray path from the focal point of the X-ray tube to the X-ray detector 13.

In summary, the X-ray diagnostic apparatus 1 of the present embodiment selects an additional filter having a larger thickness when the FPD element size is large than when the FPD element size is small. Further, the X-ray diagnostic apparatus 1 of the present embodiment selects an additional filter having a larger thickness when the FPD pixel size is large than when the FPD pixel size is small.

That is, with the above configuration and operation, according to the X-ray diagnostic apparatus 1 of the present embodiment, an appropriate additional filter is taken into consideration by considering the change in the target dose by considering the FPD element size in addition to the body thickness. Can be selected.

For example, when the FPD element size is large, the FPD pixel size is large and the target dose is small as compared with the case where the FPD element size is small. Therefore, when the FPD element size is large, it is easy to secure the target dose even when a thick additional filter is used. According to the X-ray diagnostic apparatus 1 of the present embodiment, when the FPD element size is large, an additional filter having a larger thickness is selected than when the FPD element size is small. Therefore, when it is easy to secure the target dose, by selecting an additional filter having a large X-ray reduction rate, it is possible to secure the image quality of the X-ray image and reduce the exposure dose of the subject. ..

Further, for example, when the FPD element size is small, the FPD pixel size is small and the target dose is large as compared with the case where the FPD element size is large. Therefore, when the FPD element size is small, it is difficult to secure the target dose when an additional filter having a small thickness is used. According to the X-ray diagnostic apparatus 1 of the present embodiment, when the FPD element size is small, an additional filter having a smaller thickness is selected than when the FPD pixel size is large. Therefore, when it is difficult to secure the target dose, an additional filter having a small X-ray reduction rate can be selected, so that an appropriate additional filter according to the target dose can be selected.

Further, the X-ray diagnostic apparatus 1 of the present embodiment includes information on the pixel size in the X-ray detector 13, the body thickness of the subject, the maximum output of the X-ray tube, and X-rays to the subject per unit time. Is inserted into the X-ray path from the focal point of the X-ray tube to the X-ray detector 13 of the plurality of filters based on the upper limit of the incident dose and at least one of the distances between the source image receiving surfaces. Select a filter.

In summary, the X-ray diagnostic apparatus 1 of the present embodiment detects X-rays from the focal point of an X-ray tube based on at least one of maximum power, exposure limit, and SID in addition to FPD pixel size and body thickness. By selecting the additional filter to be inserted in the path to the vessel 13 from the plurality of additional filters, a more appropriate additional filter can be selected.

(Second Embodiment)
A second embodiment will be described. This embodiment is a modification of the configuration of the first embodiment as follows. In this embodiment, the processing circuit 44 determines an additional filter to be used in the next fluoroscopy based on the number of binnings instead of the FPD element size. The number of binnings is the number of FPD detection elements corresponding to one pixel of the FPD in the control method (binning control) in which a plurality of FPD detection elements are treated as one pixel of the FPD. The same configuration, operation, and effect as in the first embodiment will not be described.

The X-ray detector 13 is provided with one type of FPD.

The processing circuit 44 uses the filter selection function 443 to perform X-rays from the focal point of the X-ray tube among the plurality of additional filters based on the number of binnings in fluoroscopy with the number of fluoroscopy N, the maximum power, the exposure limit, and the body thickness. Select an additional filter to be inserted in the path to the detector 13. Here, the FPD pixel size changes according to the change in the number of binning. That is, the processing circuit 44 uses the filter selection function 443 to focus the X-ray tube among the plurality of additional filters based on the FPD pixel size, the maximum power, the exposure limit, and the body thickness in the fluoroscopy with the number of times of fluoroscopy N. Select an additional filter to be inserted in the path from to to the X-ray detector 13.

The processing circuit 44 switches the FPD pixel size according to the selected imaging mode by controlling the number of binnings by the X-ray control function 445 and the image generation function 446. For example, when the normal mode is selected as the imaging mode, the processing circuit 44 controls the number of binning to 4 and the FPD pixel size to 4 of the FPD detection elements. In this case, the processing circuit 44 sets the detection elements of the four FPDs as one pixel of the FPD, bundles the outputs from the four detection elements into one, and reads them out as the output corresponding to one pixel of the FPD. Further, for example, when the high-definition mode is selected as the imaging mode, the processing circuit 44 controls the number of binning to 1, and controls the FPD pixel size to one of the detection elements of the FPD. In this case, the processing circuit 44 sets one FPD detection element as one pixel of the FPD, and reads out the output of each of the FPD detection elements as an output corresponding to one pixel in the FPD.

Other configurations are the same as in the first embodiment.

Hereinafter, the operation of the filter selection process executed by the X-ray diagnostic apparatus 1 will be described. FIG. 7 is a flowchart showing an example of the procedure of the filter selection process executed by the X-ray diagnostic apparatus 1 according to the present embodiment, and corresponds to the filter selection process of step S114 shown in FIG. Since the processes of steps S131 to S132 in FIG. 7 are the same as the processes of steps S121 to S122 in the first embodiment, the description thereof will be omitted.

(Filter selection process)
(Step S133)
The processing circuit 44 acquires the imaging condition in fluoroscopy with the number of fluoroscopy times N. The processing circuit 44 reads, for example, the imaging conditions for fluoroscopy with the number of fluoroscopy times N from the memory 41. The processing circuit 44 acquires the imaging condition in the next fluoroscopy by acquiring the imaging condition in the fluoroscopy with the number of fluoroscopy N. The processing circuit 44 acquires, for example, the number of binnings, the maximum power, the exposure limit, the body thickness, and the SID as imaging conditions in fluoroscopy with the number of fluoroscopy N.

(Step S134)
The processing circuit 44 reads out the corresponding correspondence table from the plurality of correspondence tables (tables) stored in the memory 41 based on the binning number in the fluoroscopy of the fluoroscopic number N acquired in the process of step S133. For example, when the number of binning is 4, the correspondence table of FIG. 5 is selected. Further, for example, when the number of binning is 1, the correspondence table of FIG. 6 is selected.

(Step S135)
The processing circuit 44 selects the number of fluoroscopy N from the filters A to D based on the correspondence table read in the process of step S134 and the maximum power, exposure limit, SID, and body thickness in fluoroscopy of the number of fluoroscopy N. Determine the additional filter used for fluoroscopy.

In the processing of steps S134 and S135, the processing circuit 44 selects an additional filter having a thickness equal to or larger than the thickness of the additional filter selected when the number of binning is large and the number of binning is small. That is, the processing circuit 44 selects an additional filter having a thickness equal to or larger than the thickness of the additional filter selected when the FPD pixel size is large and the FPD pixel size is small. For example, when the binning number is the first magnitude, the processing circuit 44 selects the first filter having the first thickness, and the binning number is the second magnitude larger than the first magnitude. In the case, a second filter having a second thickness larger than the first thickness is selected. Further, the processing circuit 44 may acquire the FPD pixel size based on the number of binnings. In this case, the processing circuit 44 selects an additional filter having a thickness equal to or larger than the thickness of the additional filter selected when the FPD pixel size is large and the FPD pixel size is small. For example, when the FPD pixel size is the first size, the processing circuit 44 selects the first filter having the first thickness, and the FPD pixel size is larger than the first size. If, a second filter having a second thickness greater than the first thickness is selected. Since the other processes are the same as the processes of steps S124 and S125 of the first embodiment, the description thereof will be omitted.

Hereinafter, the effect of the X-ray diagnostic apparatus 1 according to the present embodiment will be described.

The X-ray diagnostic apparatus 1 of the present embodiment acquires the size of the pixels in the X-ray detector 13 based on the number of detection elements corresponding to one pixel of the X-ray detector 13, and the X-ray detector 13 Based on information about the pixel size and the body thickness of the subject, the filter selected when the pixel size in the X-ray detector 13 is large and the pixel size in the X-ray detector 13 is small. A filter having a thickness greater than or equal to the thickness is selected as a filter to be inserted into the X-ray path from the focal point of the X-ray tube to the X-ray detector 13.

In summary, the X-ray diagnostic apparatus 1 of the present embodiment inserts an additional filter that is inserted into the path from the focal point of the X-ray tube to the X-ray detector 13 based on the number of binnings and the body thickness. Select from. Further, the X-ray diagnostic apparatus 1 of the present embodiment selects an additional filter having a larger thickness when the number of binning is large than when the number of binning is small.

When the number of binnings is different, the FPD pixel size is different, so that the target dose is different and the appropriate additional filter is different. With the above configuration and operation, according to the X-ray diagnostic apparatus 1 of the present embodiment, an appropriate additional filter is selected in consideration of the change in the target dose by considering the number of binnings in addition to the body thickness. be able to.

For example, when the number of binning is large, the FPD pixel size is large and the target dose is small as compared with the case where the number of binning is small. Therefore, when the number of binnings is large, it is easy to secure the target dose even when a thick additional filter is used. According to the X-ray diagnostic apparatus 1 of the present embodiment, when the number of binning is large, an additional filter having a larger thickness is selected than when the number of binning is small. Therefore, when it is easy to secure the target dose, by selecting an additional filter having a large X-ray reduction rate, it is possible to secure the image quality of the X-ray image and reduce the exposure dose of the subject. ..

Further, for example, when the number of binning is small, the FPD pixel size is small and the target dose is large as compared with the case where the number of binning is large. Therefore, when the number of binning is small, it is difficult to secure the target dose when an additional filter having a small thickness is used. According to the X-ray diagnostic apparatus 1 of the present embodiment, when the FPD pixel size is small, an additional filter having a smaller thickness is selected than when the FPD pixel size is large. Therefore, when it is difficult to secure the target dose, an additional filter having a small X-ray reduction rate can be selected, so that an appropriate additional filter according to the target dose can be selected.

(Third Embodiment)
A third embodiment will be described. This embodiment is a modification of the configuration of the first embodiment as follows. In this embodiment, the processing circuit 44 determines the additional filter to be used in the next fluoroscopy based on the pixel size in the X-ray image based on the output by the X-ray detector 13 instead of the FPD element size. The same configuration, operation, and effect as in the first embodiment will not be described.

The X-ray detector 13 is provided with one type of FPD.

The processing circuit 44 uses the filter selection function 443 to X-ray from the focal point of the X-ray tube among the plurality of additional filters based on the pixel size, the maximum power, the exposure limit, and the body thickness in the fluoroscopy with the number of times of see-through N. Select an additional filter to be inserted in the path to the detector 13.

The processing circuit 44 switches the pixel size according to the selected imaging mode by the X-ray control function 445 and the image generation function 446. For example, when the normal mode is selected as the imaging mode, the processing circuit 44 controls the pixel size to four pixels of the FPD. In this case, the processing circuit 44 bundles the outputs from the pixels of the four FPDs into one and reads them out as the output corresponding to one pixel of the X-ray image. Further, for example, when the high-definition mode is selected as the imaging mode, the processing circuit 44 controls the pixel size to one pixel of the FPD. In this case, the processing circuit 44 reads out the output of each pixel of the FPD as an output corresponding to one pixel in the X-ray image. The pixel size of one pixel of the FPD is an example of the first size of the pixel size. The pixel size of four pixels of the FPD is an example of the second size of the pixel size.

Other configurations are the same as in the first embodiment.

Hereinafter, the operation of the filter selection process executed by the X-ray diagnostic apparatus 1 will be described. FIG. 8 is a flowchart showing an example of the procedure of the filter selection process executed by the X-ray diagnostic apparatus 1 according to the present embodiment, and corresponds to the filter selection process of step S114 shown in FIG. Since the processes of steps S141 to S142 in FIG. 8 are the same as the processes of steps S121 to S122 in the first embodiment, the description thereof will be omitted.

(Filter selection process)
(Step S143)
The processing circuit 44 acquires the imaging condition in fluoroscopy with the number of fluoroscopy times N. The processing circuit 44 reads, for example, the imaging conditions for fluoroscopy with the number of fluoroscopy times N from the memory 41. The processing circuit 44 acquires the imaging condition in the next fluoroscopy by acquiring the imaging condition in the fluoroscopy with the number of fluoroscopy N. The processing circuit 44 acquires, for example, pixel size, maximum power, exposure limit, body thickness, and SID as imaging conditions in fluoroscopy with the number of fluoroscopy times N.

(Step S144)
The processing circuit 44 reads out the corresponding correspondence table from the plurality of correspondence tables (tables) stored in the memory 41 based on the pixel size in the fluoroscopy of the fluoroscopic number N acquired in the process of step S143. For example, when the pixel size is four pixels of the FPD, the correspondence table of FIG. 5 is selected. Further, for example, when the pixel size is one of the pixels of the FPD, the correspondence table of FIG. 6 is selected.

(Step S145)
The processing circuit 44 selects the number of fluoroscopy N from the filters A to D based on the correspondence table read in the process of step S144 and the maximum power, the exposure limit, the SID, and the body thickness in fluoroscopy of the number of fluoroscopy N. Determine the additional filter used for fluoroscopy.

In the processing of steps S144 and S145, the processing circuit 44 selects an additional filter having a thickness equal to or larger than the thickness of the additional filter selected when the pixel size is large or the pixel size is small. For example, when the pixel size is the first size, the processing circuit 44 selects the first filter having the first thickness, and the pixel size is the second size larger than the first size. In the case, a second filter having a second thickness larger than the first thickness is selected. Since the other processes are the same as the processes of steps S124 and S125 of the first embodiment, the description thereof will be omitted.

Hereinafter, the effect of the X-ray diagnostic apparatus 1 according to the present embodiment will be described.

The X-ray diagnostic apparatus 1 of the present embodiment X based on the output by the X-ray detector 13 based on the information on the pixel size and the body thickness of the subject in the X-ray image based on the output by the X-ray detector 13. An X-ray tube is a filter having a thickness greater than or equal to the thickness of the filter selected when the pixel size in the X-ray image based on the output by the X-ray detector 13 is small when the pixel size in the line image is large. Select as a filter to be inserted into the X-ray path from the focus of the X-ray detector 13.

In summary, the X-ray diagnostic apparatus 1 of the present embodiment has a plurality of additional filters that insert an additional filter into the path from the focal point of the X-ray tube to the X-ray detector 13 based on the pixel size and the body thickness. Select from among, and when the pixel size is large, select an additional filter having a larger thickness than when the pixel size is small.

That is, with the above configuration and operation, according to the X-ray diagnostic apparatus 1 of the present embodiment, by considering the pixel size in addition to the body thickness, an appropriate additional filter can be provided in consideration of the change in the target dose. You can choose.

For example, when the pixel size is large, the target dose is smaller than when the pixel size is small, so that it is easy to secure the target dose even when a thick additional filter is used. According to the X-ray diagnostic apparatus 1 of the present embodiment, when the pixel size is large, an additional filter having a larger thickness is selected than when the pixel size is small. Therefore, when it is easy to secure the target dose, by selecting an additional filter having a large X-ray reduction rate, it is possible to secure the image quality of the X-ray image and reduce the exposure dose of the subject. ..

Further, for example, when the pixel size is small, the target dose is larger than when the pixel size is large, so that it is difficult to secure the target dose when an additional filter having a small thickness is used. According to the X-ray diagnostic apparatus 1 of the present embodiment, when the pixel size is small, an additional filter having a smaller thickness is selected than when the pixel size is large. Therefore, when it is difficult to secure the target dose, an additional filter having a small X-ray reduction rate can be selected, so that an appropriate additional filter according to the target dose can be selected.

(Fourth Embodiment)
A fourth embodiment will be described. This embodiment is a modification of the configuration of the first embodiment as follows. In this embodiment, the processing circuit 44 determines an additional filter to be used in the next fluoroscopy based on the field size instead of the FPD element size. The same configuration, operation, and effect as in the first embodiment will not be described.

The processing circuit 44 uses the filter selection function 443 to perform X-rays from the focal point of the X-ray tube among the plurality of additional filters based on the visual field size, the maximum power, the exposure limit, and the body thickness in the fluoroscopy with the number of times of fluoroscopy N. Select an additional filter to be inserted in the path to the detector 13.

Other configurations are the same as in the first embodiment.

Hereinafter, the operation of the filter selection process executed by the X-ray diagnostic apparatus 1 will be described. FIG. 9 is a flowchart showing an example of the procedure of the filter selection process executed by the X-ray diagnostic apparatus 1 according to the present embodiment, and corresponds to the filter selection process of step S114 shown in FIG. Since the processes of steps S151 to S152 in FIG. 9 are the same as the processes of steps S121 to S122 in the first embodiment, the description thereof will be omitted.

(Filter selection process)
(Step S153)
The processing circuit 44 acquires the imaging conditions for fluoroscopy with the number of fluoroscopy times N. The processing circuit 44 reads, for example, the imaging conditions for fluoroscopy with the number of fluoroscopy times N from the memory 41. The processing circuit 44 acquires the imaging condition in the next fluoroscopy by acquiring the imaging condition in the fluoroscopy with the number of fluoroscopy N. The processing circuit 44 acquires, for example, the visual field size, the maximum power, the exposure limit, the body thickness, and the SID as imaging conditions in fluoroscopy with the number of fluoroscopy N.

(Step S154)
The processing circuit 44 reads out the corresponding correspondence table from the plurality of correspondence tables (tables) stored in the memory 41 based on the visual field size in the fluoroscopy of the fluoroscopic number N acquired in the process of step S153. For example, when the visual field size is the first size, the correspondence table of FIG. 6 is selected. Further, for example, when the visual field size is a second size larger than the first size, the correspondence table of FIG. 5 is selected.

(Step S155)
The processing circuit 44 selects the number of fluoroscopy N from the filters A to D based on the correspondence table read in the process of step S154 and the maximum power, the exposure limit, the SID, and the body thickness in fluoroscopy of the number of fluoroscopy N. Determine the additional filter used for fluoroscopy.

In the processing of steps S154 and S155, the processing circuit 44 selects an additional filter having a thickness equal to or larger than the thickness of the additional filter selected when the visual field size is large and the visual field size is small. For example, when the field of view size is the first size, the processing circuit 44 selects the first filter having the first thickness, and the field of view size is a second size larger than the first size. In the case, a second filter having a second thickness larger than the first thickness is selected. Since the other processes are the same as the processes of steps S124 and S125 of the first embodiment, the description thereof will be omitted.

Hereinafter, the effect of the X-ray diagnostic apparatus 1 according to the present embodiment will be described.

In the X-ray diagnostic apparatus 1 of the present embodiment, when the size of the X-ray irradiation area is large, the size of the X-ray irradiation area is increased based on the size of the X-ray irradiation area and the information on the body thickness of the subject. A filter having a thickness greater than or equal to the thickness of the filter selected when it is small is selected as a filter to be inserted into the X-ray path from the focal point of the X-ray tube to the X-ray detector 13.

In summary, the X-ray diagnostic apparatus 1 of the present embodiment inserts an additional filter into the path from the focal point of the X-ray tube to the X-ray detector 13 based on the visual field size and the body thickness. Select from among, and select an additional filter with a larger thickness when the field size is large than when the field size is small.

When fluoroscopy is performed with different field sizes, the effect of scattered radiation and the target dose are different, so the appropriate additional filter is different. With the above configuration and operation, according to the X-ray diagnostic apparatus 1 of the present embodiment, it is appropriate to consider the influence of scattered radiation and the change in the target dose by considering the visual field size in addition to the body thickness. Additional filters can be selected.

For example, when the visual field size is large, the area irradiated with X-rays is larger than when the visual field size is small, so that the scattered rays increase. As the scattered radiation increases, the dose of X-rays incident on the X-ray detector 13 increases, so that it is easy to secure the target dose even when a thick additional filter is used. According to the X-ray diagnostic apparatus 1 of the present embodiment, when the visual field size is large, an additional filter having a larger thickness is selected than when the visual field size is small. Therefore, when it is easy to secure the target dose, by selecting an additional filter having a large X-ray reduction rate, it is possible to secure the image quality of the X-ray image and reduce the exposure dose of the subject. ..

Further, for example, when the visual field size is small, the area irradiated with X-rays is smaller than when the visual field size is large, so that the scattered rays are reduced. When the scattered radiation decreases, the dose of X-rays incident on the X-ray detector 13 decreases, so that it is difficult to secure the target dose when an additional filter having a small thickness is used. According to the X-ray diagnostic apparatus 1 of the present embodiment, when the visual field size is small, an additional filter having a smaller thickness is selected than when the visual field size is large. Therefore, when it is difficult to secure the target dose, an additional filter having a small X-ray reduction rate can be selected, so that an appropriate additional filter according to the target dose can be selected.

(Fifth Embodiment)
A fifth embodiment will be described. This embodiment is a modification of the configuration of the first embodiment as follows. In this embodiment, the processing circuit 44 determines the additional filter to be used in the next fluoroscopy based on the focal size instead of the FPD element size. The same configuration, operation, and effect as in the first embodiment will not be described.

The processing circuit 44 uses the filter selection function 443 to perform X-rays from the focal point of the X-ray tube among the plurality of additional filters based on the focal size, maximum power, exposure limit, and body thickness in fluoroscopy with the number of times of fluoroscopy N. Select an additional filter to be inserted in the path to the detector 13.

Other configurations are the same as in the first embodiment.

Hereinafter, the operation of the filter selection process executed by the X-ray diagnostic apparatus 1 will be described. FIG. 10 is a flowchart showing an example of the procedure of the filter selection process executed by the X-ray diagnostic apparatus 1 according to the present embodiment, and corresponds to the filter selection process of step S114 shown in FIG. Since the processes of steps S161 to S162 in FIG. 10 are the same as the processes of steps S121 to S122 in the first embodiment, the description thereof will be omitted.

(Filter selection process)
(Step S163)
The processing circuit 44 acquires the imaging condition in fluoroscopy with the number of fluoroscopy times N. The processing circuit 44 reads, for example, the imaging conditions for fluoroscopy with the number of fluoroscopy times N from the memory 41. The processing circuit 44 acquires the imaging condition in the next fluoroscopy by acquiring the imaging condition in the fluoroscopy with the number of fluoroscopy N. The processing circuit 44 acquires, for example, the focal size, the maximum power, the exposure limit, the body thickness, and the SID as imaging conditions in fluoroscopy with the number of fluoroscopy N.

(Step S164)
The processing circuit 44 reads out the corresponding correspondence table from the plurality of correspondence tables (tables) stored in the memory 41 based on the focal size in the fluoroscopy of the fluoroscopic number N acquired in the process of step S163. For example, when the focal size is medium focus, the correspondence table of FIG. 5 is selected. Further, for example, when the focal size is a small focal point, the correspondence table of FIG. 6 is selected.

(Step S165)
The processing circuit 44 has a fluoroscopy count N from among the filters A to D based on the correspondence table read in the process of step S164 and the maximum power, exposure limit, SID, and body thickness in fluoroscopy of the fluoroscopic count N. Determine the additional filter used for fluoroscopy.

In the processing of steps S164 and S165, the processing circuit 44 selects an additional filter having a thickness equal to or larger than the thickness of the additional filter selected when the focal size is large and the focal size is small. For example, the processing circuit 44 selects a first filter having a first thickness when the focus size is small, and a second thickness which is larger than the first thickness when the focus size is medium focus. Select a second filter with. Since the other processes are the same as the processes of steps S124 and S125 of the first embodiment, the description thereof will be omitted.

Hereinafter, the effect of the X-ray diagnostic apparatus 1 according to the present embodiment will be described.

The X-ray diagnostic apparatus 1 of the present embodiment X-rays from the focal point of the X-ray tube to the X-ray detector 13 based on the information on the body thickness of the subject and the size of the focal point of the tube of the X-ray tube. Select the filter to be inserted in the path of. Further, when the focus size is large, a filter having a thickness equal to or larger than the thickness of the filter selected when the focus size is small is used as an X-ray path from the focal point of the X-ray tube to the X-ray detector 13. Select as the filter to be inserted into.

In summary, the X-ray diagnostic apparatus 1 of the present embodiment inserts into the path from the focal point of the X-ray tube to the X-ray detector 13 based on the focal size, the maximum power, the exposure limit, and the body thickness. Select an additional filter from multiple additional filters. Further, the X-ray diagnostic apparatus 1 of the present embodiment selects an additional filter having a larger thickness when the focal size is large than when the focal size is small.

When fluoroscopy is performed at different focal sizes, the maximum power of the tube is different, so the appropriate additional filter is different. With the above configuration and operation, according to the X-ray diagnostic apparatus 1 of the present embodiment, an appropriate additional filter is selected in consideration of the change in maximum power by considering the focal size in addition to the body thickness. be able to.

For example, when the focal size is large, the maximum power of the tube is large and the output of the tube is likely to be large as compared with the case where the focal size is small. Therefore, it is easy to secure the target dose even when a thick additional filter is used. According to the X-ray diagnostic apparatus 1 of the present embodiment, when the focal size is large, an additional filter having a larger thickness is selected than when the focal size is small. Therefore, when it is easy to secure the target dose, by selecting an additional filter having a large X-ray reduction rate, it is possible to secure the image quality of the X-ray image and reduce the exposure dose of the subject. ..

Further, for example, when the focal size is small, the maximum power of the tube is small as compared with the case where the focal size is large, and it is difficult to increase the output of the tube. Therefore, it is difficult to secure the target dose when an additional filter having a small thickness is used. According to the X-ray diagnostic apparatus 1 of the present embodiment, when the focal size is small, an additional filter having a smaller thickness is selected than when the focal size is large. Therefore, when it is difficult to secure the target dose, an additional filter having a small X-ray reduction rate can be selected, so that an appropriate additional filter according to the target dose can be selected.

(Sixth Embodiment)
A sixth embodiment will be described. This embodiment is a modification of the configuration of the first embodiment as follows. In this embodiment, the processing circuit 44 determines the additional filter to be used in the next fluoroscopy based on the pulse rate instead of the FPD element size. The same configuration, operation, and effect as in the first embodiment will not be described.

The processing circuit 44 uses the filter selection function 443 to X-ray from the focal point of the X-ray tube among the plurality of additional filters based on the pulse rate, the maximum power, the exposure limit, and the body thickness in the fluoroscopy of the number of times of fluoroscopy N. Select an additional filter to be inserted in the path to the detector 13.

Other configurations are the same as in the first embodiment.

Hereinafter, the operation of the filter selection process executed by the X-ray diagnostic apparatus 1 will be described. FIG. 11 is a flowchart showing an example of the procedure of the filter selection process executed by the X-ray diagnostic apparatus 1 according to the present embodiment, and corresponds to the filter selection process of step S114 shown in FIG. Since the processes of steps S171 to S172 in FIG. 11 are the same as the processes of steps S121 to S122 in the first embodiment, the description thereof will be omitted.

(Filter selection process)
(Step S173)
The processing circuit 44 acquires the imaging condition in fluoroscopy with the number of fluoroscopy times N. The processing circuit 44 reads, for example, the imaging conditions for fluoroscopy with the number of fluoroscopy times N from the memory 41. The processing circuit 44 acquires the imaging condition in the next fluoroscopy by acquiring the imaging condition in the fluoroscopy with the number of fluoroscopy N. The processing circuit 44 acquires, for example, a pulse rate, a maximum power, an exposure limit, a body thickness, and a SID as imaging conditions in fluoroscopy with the number of fluoroscopy times N.

(Step S174)
The processing circuit 44 reads out the corresponding correspondence table from the plurality of correspondence tables (tables) stored in the memory 41 based on the pulse rate in the fluoroscopy of the fluoroscopic number N acquired in the process of step S173. For example, when the pulse rate is the first magnitude, the correspondence table of FIG. 6 is selected. Further, for example, when the pulse rate is a second magnitude larger than the first magnitude, the correspondence table of FIG. 5 is selected.

(Step S175)
The processing circuit 44 selects the number of fluoroscopy N from the filters A to D based on the correspondence table read in the process of step S174 and the maximum power, exposure limit, SID, and body thickness in fluoroscopy of the number of fluoroscopy N. Determine the additional filter used for fluoroscopy.

In the processing of steps S174 and S175, the processing circuit 44 selects an additional filter having a thickness equal to or larger than the thickness of the additional filter selected when the pulse rate is large or the pulse rate is small. For example, when the pulse rate is the first magnitude, the processing circuit 44 selects the first filter having the first thickness, and the pulse rate is the second magnitude larger than the first magnitude. In the case, a second filter having a second thickness larger than the first thickness is selected. Since the other processes are the same as the processes of steps S124 and S125 of the first embodiment, the description thereof will be omitted.

Hereinafter, the effect of the X-ray diagnostic apparatus 1 according to the present embodiment will be described.

The X-ray diagnostic apparatus 1 of the present embodiment moves from the focal point of the X-ray tube to the X-ray detector 13 based on the information on the body thickness of the subject and the pulse rate of the X-ray emitted from the X-ray tube. Select the filter to be inserted in the X-ray path of. Further, when the pulse rate is large, a filter having a thickness equal to or larger than the thickness of the filter selected when the pulse rate is small is inserted into the X-ray path from the focal point of the X-ray tube to the X-ray detector 13. Select as a filter.

In summary, the X-ray diagnostic apparatus 1 of the present embodiment inserts into the path from the focal point of the X-ray tube to the X-ray detector 13 based on the pulse rate, the maximum power, the exposure limit, and the body thickness. Select an additional filter from multiple additional filters. Further, the X-ray diagnostic apparatus 1 of the present embodiment selects an additional filter having a larger thickness when the pulse rate is large than when the pulse rate is small.

When fluoroscopy is performed at different pulse rates, the relationship between the dose of X-rays incident on the subject and the exposure limit changes because the dose of X-rays incident on the subject in fluoroscopy is different. Therefore, when fluoroscopy is performed at different pulse rates, the appropriate additional filter is different. With the above configuration and operation, according to the X-ray diagnostic apparatus 1 of the present embodiment, the relationship of the dose of X-rays incident on the subject with respect to the exposure limit is considered by considering the pulse rate in addition to the body thickness. Then, an appropriate additional filter can be selected.

For example, when the pulse rate is large, the dose of X-rays incident on the subject is large and the exposure limit is easily reached as compared with the case where the pulse rate is small. According to the X-ray diagnostic apparatus 1 of the present embodiment, when the pulse rate is large, an additional filter having a larger thickness is selected than when the pulse rate is small. Therefore, when it is easy to reach the upper limit of exposure, by selecting an additional filter having a large reduction rate of X-rays, it is possible to prevent the dose of X-rays incident on the subject from exceeding the upper limit of exposure.

Further, for example, when the pulse rate is small, the dose of X-rays incident on the subject is small as compared with the case where the pulse rate is large, and it is difficult to reach the exposure limit. According to the X-ray diagnostic apparatus 1 of the present embodiment, when the pulse rate is small, an additional filter having a smaller thickness is selected than when the pulse rate is large. Therefore, when it is difficult to reach the exposure limit, an additional filter with a small X-ray reduction rate is selected, so that an appropriate additional filter according to the relationship of the dose of X-rays incident on the subject with respect to the exposure limit can be obtained. You can choose.

(7th Embodiment)
A seventh embodiment will be described. This embodiment is a modification of the configuration of the first embodiment as follows. The same configuration, operation, and effect as in the first embodiment will not be described.

The processing circuit 44 uses the imaging condition setting function 442 to perform an inspection including a plurality of fluoroscopy executions, based on the output of the X-ray detector 13 in the fluoroscopy executed immediately before, and X-rays in the fluoroscopy executed next. Determine the size of the focal point of. Further, the processing circuit 44 sets the focal size of the X-ray according to the determined result. Here, the "focus size" and the "focus size" may have a one-to-one correspondence or a many-to-one correspondence. In the case of a one-to-one correspondence, both the "focus size" and the "focus size" may be determined and set as "small focus" or "medium focus". Alternatively, even in the case of a one-to-one correspondence, when the control grid electrode is used, both the "focus size" and the "focus size" are determined and set as values in the range of 0.2 to 0.7 mm, for example. You may. On the other hand, in the case of many-to-one correspondence, the "focus size" is determined as a value in the range of 0.2 to 0.4 mm, for example, and the "focal size" is set as a small focus. You may. Alternatively, the "focus size" may be determined as a value within the range of, for example, 0.5 to 0.7 mm, and the "focus size" may be set as the medium focus.

Specifically, the processing circuit 44 determines the first fluoroscopy based on the output of the X-ray detector 13 in the first fluoroscopy executed in response to the operation to the input interface 43 by the imaging condition setting function 442. The focal size in the second fluoroscopy, which is later performed in response to an operation on the input interface 43, is determined, and based on the output of the X-ray detector 13 in the second fluoroscopy, to the input interface 43 after the second fluoroscopy. Determine the focal size in the third fluoroscopy performed in response to the operation of. Supplementally, the processing circuit 44, for example, in the first moving image imaging and the second moving image imaging, based on the output of the X-ray detector 13 in the previous frame, the conditions of X-ray irradiation in the subsequent frame and X Control is performed to set at least one of the gains applied to the line image. Further, the processing circuit 44 focuses on the X-rays in the second moving image imaging based on the output of the X-ray detector 13 in the first moving image imaging through the conditions of the X-ray irradiation in the first moving image imaging. Determine the size of. Further, the processing circuit 44 focuses the X-rays in the third moving image imaging based on the output of the X-ray detector 13 in the second moving image imaging through the conditions of the X-ray irradiation in the second moving image imaging. Determine the size of.

Further, the processing circuit 44 acquires the X-ray condition in the first fluoroscopy based on the X-ray image generated by the output of the X-ray detector 13 in the first fluoroscopy, and X in the first fluoroscopy. The focal size in the second fluoroscopy may be determined based on the line condition. The first perspective is an example of the first moving image imaging, the second perspective is an example of the second moving image imaging, and the third perspective is an example of the third moving image imaging.

Other configurations are the same as in the first embodiment.

Hereinafter, the operation of the filter selection process executed by the X-ray diagnostic apparatus 1 will be described. FIG. 12 is a flowchart showing an example of the procedure of the imaging condition setting process executed by the X-ray diagnostic apparatus 1 according to the present embodiment, and corresponds to the imaging condition setting process of step S101 shown in FIG. Since the processes of steps S211 to S212 and step S214 in FIG. 12 are the same as the processes of steps S111 to S112 and step S114 in the first embodiment, the description thereof will be omitted.

(Imaging condition setting process)
(Step S213)
The processing circuit 44 reads the default imaging condition for the first fluoroscopy after the start of the examination from the memory 41, and sets the read default imaging condition as the imaging condition for the next fluoroscopy to be executed. At this time, the processing circuit 44 sets a small focus as the focal size in the next fluoroscopy.

(Step S215)
In the fluoroscopy with the number of fluoroscopy N, the processing circuit 44 has an X-ray detector incident dose at the X-ray generator 12 for each of the case of performing fluoroscopy at the focal size of the small focus and the case of performing fluoroscopy at the focal size of the medium focus. Is calculated as close as possible to the target dose (hereinafter referred to as an estimated imaging condition). The estimated imaging condition is an imaging condition when the conditions relating to the short-time rating and the continuous rating of the tube are satisfied and the X-ray detector incident dose is as close as possible to the target dose. Specifically, for example, when the number of times of fluoroscopy is N = 2, the processing circuit 44 has the focal size, tube voltage, tube current, and X-ray focus size of X-rays acquired based on the output of the X-ray detector 13 in the first moving image imaging. The imaging condition estimation value in the second moving image imaging may be calculated based on the pulse width, the AGC magnification, and the filter specific information. Here, when the number of fluoroscopy N = 2, the first moving image imaging and the second moving image imaging correspond to the first (N-1) moving image imaging and the Nth moving image imaging, respectively. Further, when the number of times of see-through N = 3, the processing circuit 44 has the X-ray focal size, tube voltage, tube current and pulse width, and AGC acquired based on the output of the X-ray detector 13 in the second moving image imaging. The imaging condition estimation value in the third moving image imaging may be calculated based on the magnification and the filter specific information. Similarly, when the number of fluoroscopy N = 3, the second moving image imaging and the third moving image imaging correspond to the first (N-1) moving image imaging and the Nth moving image imaging, respectively.

The imaging condition estimated values are the X-ray conditions (hereinafter referred to as X-ray condition estimated values) when the X-ray detector incident dose is as close as possible to the target dose in the X-ray generator 12, and the X-ray generator 12 Includes AGC magnification (hereinafter referred to as AGC magnification estimation value) that is predicted to be applied by AGC when the X-ray detector incident dose is as close as possible to the target dose. The X-ray condition estimated values are the tube voltage (hereinafter referred to as the tube voltage estimated value) when the X-ray detector incident dose is as close as possible to the target dose in the X-ray generator 12, and the X in the X-ray generator 12. When the X-ray detector incident dose is as close as possible to the target dose (hereinafter referred to as the tube current estimated value) and when the X-ray detector incident dose is as close as possible to the target dose in the X-ray generator 12. (Hereinafter, referred to as a pulse width estimated value) and the pulse width of. The imaging condition estimated value is a tube voltage estimated value that satisfies the conditions related to the output of the X-ray tube (hereinafter referred to as a target output) necessary for ensuring the image quality of the X-ray image, and a tube current estimated value that satisfies the condition. , At least one of a pulse width estimated value that satisfies the condition regarding the target output and an AGC magnification estimated value that satisfies the condition regarding the target output may be included.

As a process for calculating the estimated imaging condition, for example, the X-ray condition for fluoroscopy this time is set to X {kV, mA, msec, AGC}, and the function of the previous or current condition is h (Focus, BF, _{immediately before} BF, kV _{just before} mA _{just before} msec _{immediately before,} when the AGC _{immediately before),} and executes processing based on the following equation.

X {kV, mA, msec, AGC} = h (Focus, BF, BF _{immediately before,} kV _{just before,} mA _{just before,} msec _{shortly before,} AGC _{immediately before)}
However, in the above equation, kV: tube voltage, mA: tube current, msec: pulse width, AGC: AGC magnification, Focus: focus size, BF: filter specific information, subscript "immediately before": condition in the previous fluoroscopy, appendix No characters: This is the condition for this fluoroscopy.

In the process of calculating the imaging condition estimated value, the processing circuit 44 first acquires the imaging condition in fluoroscopy with the number of fluoroscopy N-1. The processing circuit 44 acquires, for example, the imaging conditions for fluoroscopy having the number of fluoroscopy N-1 stored in the memory 41 by reading out the imaging conditions for fluoroscopy. The processing circuit 44 acquires the imaging conditions for fluoroscopy performed immediately before the start of the examination by acquiring the imaging conditions for fluoroscopy with the number of fluoroscopy N-1. The processing circuit 44 acquires, for example, the focal size, filter specific information, tube voltage, tube current, pulse width, and AGC magnification as imaging conditions in fluoroscopy with the number of fluoroscopy N-1. As described above, during fluoroscopy, feedback control is performed to change the X-ray conditions and the like based on changes in subject conditions, and at the end of fluoroscopy, the tube voltage, tube current, pulse width, and AGC magnification are measured. At least one of them is in a state of being appropriately controlled according to changes in subject conditions. Therefore, by acquiring the imaging conditions in fluoroscopy executed immediately before, it is possible to acquire the imaging conditions appropriately controlled according to the change in the subject conditions. It should be noted that the arithmetic processing based on the X-ray image generated in the fluoroscopy executed immediately before is used to calculate the imaging conditions that are more appropriately controlled according to the change in the subject conditions, and the calculated imaging conditions are executed immediately before. It may be acquired as an imaging condition in fluoroscopy.

Next, the processing circuit 44 calculates the target output based on the focal size, filter specific information, tube voltage, tube current, pulse width, and AGC magnification in fluoroscopy with the number of fluoroscopy N-1. The processing circuit 44 has a tube voltage estimated value Vp1, a tube current estimated value Ip1, and a pulse width estimated value Wp1 in the case of performing fluoroscopy at a focal size of a small focus based on the target output and the filter specific information in the see-through count N. , And the AGC magnification estimated value Mp1, the tube voltage estimated value Vp2, the tube current estimated value Ip2, the pulse width estimated value Wp2, and the AGC magnification estimated value Mp2 in the case of performing fluoroscopy at the focal size of the central focus, respectively. calculate. When the focal size of each of the small focus and the medium focus is the same as the immediately preceding focal size, an imaging condition estimated value representing substantially the same imaging condition as the immediately preceding imaging condition is calculated. Supplementally, for example, when the number of fluoroscopy N = 2, the processing circuit 44 calculates the imaging condition estimated value in the second moving image imaging for each of the plurality of focal sizes having different X-ray focal sizes, and X. The imaging condition estimated value corresponding to the focal size determined as the focal size of the line is determined as the imaging condition in the second moving image imaging. Similarly, for example, when the number of fluoroscopy N = 3, the processing circuit 44 calculates the imaging condition estimated value in the third moving image imaging for each of the plurality of focal sizes having different X-ray focal sizes. The imaging condition estimated value corresponding to the focal size determined as the focal size of the X-ray is determined as the imaging condition in the third moving image imaging.

(Step S216)
The processing circuit 44 determines whether or not the focal size of the fluoroscopy of the fluoroscopy number N-1 is a small focal point based on the imaging conditions in the fluoroscopy of the fluoroscopy number N-1 acquired in step S215. When the focal size of the fluoroscopy of the number of fluoroscopy N-1 is a small focal point (step S216-Yes), the process proceeds to step S217. When the fluoroscopic focus size of the fluoroscopic number N-1 is not a small focus (step S216-No), the processing circuit 44 determines that the fluoroscopic focal size of the fluoroscopic number N-1 is a medium focal point, and the process is performed in step S221. Proceed to.

(Step S217)
The processing circuit 44 determines whether or not the tube voltage estimated value Vp1 is equal to or less than the threshold value Vth1. The threshold value Vth1 is a value for determining whether or not the contrast of the generated X-ray image satisfies a predetermined condition. The threshold value Vth1 is, for example, a value determined from the range of 20 to 150 kV. A predetermined value may be set for the threshold value Vth1, and the threshold value Vth1 may be input by the operator for each inspection. The threshold value Vth1 is an example of a determination value. The threshold value Vth1 is an example of the first value. When the tube voltage estimated value Vp1 is equal to or less than the threshold value Vth1 (step S217-Yes), the process proceeds to step S218. When the tube voltage estimated value Vp1 is not equal to or less than the threshold value Vth1 (step S217-No), that is, when the tube voltage estimated value Vp1 is larger than the threshold value Vth1, the process proceeds to step S219.

(Step S218)
The processing circuit 44 determines whether or not the exposure limit arrival index R is equal to or less than the threshold value β. Here, the exposure limit arrival index R (= G / L × 100 [%]) is the ratio of the exposure dose estimated value G to the exposure limit L. The exposure limit (Dose Limit) L is an upper limit value relating to the dose of X-rays (incident dose rate) incident on the subject per unit time. That is, the exposure limit L is the upper limit of the exposure dose. The exposure limit L is set in advance according to, for example, the country of use. The exposure limit L is, for example, a value such as 50 mGr / min or 87 mGr / min. The radiation dose estimated value G is an X-ray that is predicted to be incident on the subject when fluoroscopy is performed with the number of fluoroscopy N, using the imaging condition estimated value when fluoroscopy is performed at the focal size of the middle focus as the imaging condition. The dose. The threshold value β is a value for determining whether or not there is a sufficient margin of the exposure dose estimated value G with respect to the exposure limit L. The threshold value β is an example of the dose determination value. The threshold value β is, for example, a value defined from the range of 90 to 99%. A predetermined value may be set for the threshold value β, and the threshold value β may be input by the operator for each fluoroscopy.

In the process of step S218, the processing circuit 44 first bases the tube voltage estimated value Vp2, the tube current estimated value Ip2, the pulse width estimated value Wp2, the AGC magnification estimated value Mp2, and the filter specific information in the Nth fluoroscopy. , Calculate the exposure dose estimate G. Then, the exposure limit arrival index R is calculated based on the exposure dose estimated value G and the exposure limit L. When the exposure limit arrival index R is equal to or less than the threshold value β (step S218-Yes), the processing circuit 44 performs fluoroscopy with the number of fluoroscopy N using the imaging condition estimated value corresponding to the middle focus as the imaging condition, and the exposure limit L It is determined that there is a sufficient margin of the incident dose rate with respect to the above, and the process proceeds to step S220. When the exposure limit arrival index R is larger than the threshold value β (step S218-No), the processing circuit 44 refers to the exposure limit L when performing fluoroscopy for the number of fluoroscopy N using the imaging condition estimated value corresponding to the middle focus as the imaging condition. It is determined that there is not enough margin for the incident dose rate, and the process proceeds to step S219.

(Step S219)
The processing circuit 44 sets the focal size in fluoroscopy of the number of fluoroscopy N to a small focal point. Further, the processing circuit 44 sets an image pickup condition estimated value corresponding to the small focus as an image pickup condition in fluoroscopy with the number of fluoroscopy N. At this time, the processing circuit 44 sets the tube voltage estimated value Vp1 as the tube voltage in fluoroscopy with the number of fluoroscopy N, the tube current estimated value Ip1 as the tube current in fluoroscopy with the number of fluoroscopy N, and the pulse width estimated value Wp1 as the number of fluoroscopy. It is set as the pulse width in fluoroscopy of N, and the AGC magnification estimated value Mp1 is set as the AGC magnification in fluoroscopy of the number of fluoroscopy N. Then, the processing circuit 44 ends the imaging condition setting process, and the process proceeds to step S103.

(Step S220)
The processing circuit 44 sets the focal size in fluoroscopy with the number of fluoroscopy N to be the middle focus. Further, the processing circuit 44 sets the estimated image condition corresponding to the middle focus as the imaging condition in fluoroscopy with the number of fluoroscopy N. At this time, the processing circuit 44 sets the tube voltage estimated value Vp2 as the tube voltage in fluoroscopy with the number of fluoroscopy N, the tube current estimated value Ip2 as the tube current in fluoroscopy with the number of fluoroscopy N, and the pulse width estimated value Wp2 as the fluoroscopy count. It is set as the pulse width in fluoroscopy of N, and the AGC magnification estimated value Mp2 is set as the AGC magnification in fluoroscopy of the number of fluoroscopy N. Then, the processing circuit 44 ends the imaging condition setting process, and the process proceeds to step S103.

(Step S221)
The processing circuit 44 determines whether or not the tube voltage estimated value Vp1 is equal to or less than the threshold value Vth2. The threshold value Vth2 is smaller than the threshold value Vth1 by the set value α1. That is, Vth2 = Vth1-α. The set value α1 is a value representing a margin of the tube voltage for determining the switching from the middle focus to the small focus, and is, for example, a value determined from the range of 1 to 10 kV. The set value α1 may be set to a predetermined value, or may be input by the operator for each inspection. The threshold value Vth2 is an example of the determination value. The threshold value Vth2 is an example of the second value. When the tube voltage estimated value Vp1 is equal to or less than the threshold value Vth2 (step S221-Yes), the process proceeds to step S222. When the tube voltage estimated value Vp1 is not equal to or less than the threshold value Vth2 (step S221-No), that is, when the tube voltage estimated value Vp1 is larger than the threshold value Vth2, the process proceeds to step S223.

(Step S222)
The process of step S222 is the same as the process of step S219. That is, the processing circuit 44 sets the focal size in fluoroscopy with the number of fluoroscopy N to be a small focal point. Then, the processing circuit 44 ends the imaging condition setting process, and the process proceeds to step S103.

(Step S223)
The process of step S223 is the same as the process of step S220. That is, the processing circuit 44 sets the focal size in fluoroscopy with the number of fluoroscopy N to be the middle focus. Then, the processing circuit 44 ends the imaging condition setting process, and the process proceeds to step S103.

When the imaging condition setting process is completed, the processing circuit 44 executes fluoroscopy with the number of fluoroscopy N based on the imaging conditions set in the imaging condition setting process. Then, when the next fluoroscopy is executed after the fluoroscopy of the number of fluoroscopy times N is completed, the processing circuit 44 again executes the imaging condition setting process in step S101. At this time, the processing circuit 44 performs imaging including the focal size in fluoroscopy with the number of fluoroscopy N + 1 based on the X-ray condition in fluoroscopy with the number of fluoroscopy N in the same manner as the process for setting the imaging condition in fluoroscopy with the number of fluoroscopy N + 1. Determine the conditions.

Hereinafter, the effect of the X-ray diagnostic apparatus 1 according to the present embodiment will be described.

The X-ray diagnostic apparatus 1 of the present embodiment transfers to the operation unit after the first moving image imaging based on the output of the X-ray detector 13 in the first moving image imaging executed in response to the operation to the operation unit. The magnitude of the X-ray focus in the second moving image imaging performed in response to the operation is determined. Further, based on the output of the X-ray detector 13 in the second moving image imaging, the magnitude of the X-ray focus in the third moving image imaging executed in response to the operation to the operation unit after the second moving image imaging. To determine.

In summary, the X-ray diagnostic apparatus 1 of the present embodiment responds to the operation to the input interface 43 based on the output of the X-ray detector 13 in the fluoroscopy executed immediately before the operation to the input interface 43. Determine the focal size in the next fluoroscopy performed.

For example, the X-ray diagnostic apparatus 1 of the present embodiment inputs after the fluoroscopy of the fluoroscopy count N-1 based on the X-ray condition in the fluoroscopy of the fluoroscopy count N-1 executed in response to the operation to the input interface 43. The focal size in fluoroscopy of the number of fluoroscopy N to be executed in response to the operation to the interface 43 is determined, and the operation to the input interface 43 is performed after fluoroscopy of the number of fluoroscopy N based on the X-ray condition in the fluoroscopy of the number of fluoroscopy N. The focal size in fluoroscopy with the number of fluoroscopy N + 1 performed accordingly is determined.

Further, the X-ray diagnostic apparatus 1 of the present embodiment determines the magnitude of the X-ray focus at the start of the second moving image imaging based on the output of the X-ray detector 13 at the end of the first moving image imaging. The size of the X-ray focus at the start of the third moving image imaging is determined based on the output of the X-ray detector 13 at the end of the second moving image imaging.

For example, the X-ray diagnostic apparatus 1 of the present embodiment determines the size of the focal point of the X-ray at the start of the fluoroscopy count N based on the X-ray condition at the end of the fluoroscopy count N-1 and performs fluoroscopy. Based on the output of the X-ray condition at the end of fluoroscopy with the number of times N, the magnitude of the X-ray focus at the start of fluoroscopy with the number of fluoroscopy N + 1 is determined.

Further, the X-ray diagnostic apparatus 1 of the present embodiment uses a specific X-ray focal size for the second moving image imaging based on the output of the X-ray detector 13 in the first moving image imaging. The estimated value of the imaging condition satisfying the target output in the above is calculated, and the size of the X-ray focus in the second moving image imaging is determined based on the estimated value of the imaging condition in the second moving image imaging. Further, an imaging condition estimated value for the third moving image imaging is calculated based on the output of the X-ray detector 13 in the second moving image imaging, and a third moving image is calculated based on the imaging condition estimated value in the third moving image imaging. Determines the magnitude of the X-ray focus in imaging.

For example, the X-ray diagnostic apparatus 1 of the present embodiment calculates the tube voltage estimated value Vp1 in fluoroscopy of the fluoroscopy count N based on the X-ray condition in fluoroscopy of the fluoroscopy count N-1, and is based on the tube voltage estimated value Vp1. The focal size in fluoroscopy with the number of fluoroscopy N is determined, the tube voltage estimated value Vp1 in fluoroscopy with the number of fluoroscopy N + 1 is calculated based on the X-ray condition in fluoroscopy with the number of fluoroscopy N + 1, and the number of fluoroscopy N + 1 is calculated based on the tube voltage estimated value Vp1. Determines the focal size in fluoroscopy.

That is, with the above configuration and operation, according to the X-ray diagnostic apparatus 1 of the present embodiment, the next fluoroscopy executed by re-depressing the foot switch based on the output of the X-ray detector 13 in the immediately preceding fluoroscopy. The focal size in can be determined. Therefore, in the next fluoroscopy, the focal size can be set according to the X-ray condition in the immediately preceding fluoroscopy. Therefore, even if the thickness of the subject changes during the previous fluoroscopy and the appropriate focal size is changed to generate an X-ray image with contrast satisfying a predetermined condition, feedback control is used. The appropriate focal size for the next fluoroscopy can be automatically set based on the X-ray conditions controlled to the appropriate values according to the thickness of the subject. This makes it possible to improve the image quality of the X-ray image generated in the next fluoroscopy. For example, when the subject thickness is thin and the tube output has a margin, a sharp image can be generated by setting a small focus. On the other hand, when the subject is thick and the tube voltage is high at a small focus, it is possible to generate an image with strong contrast or an image with less noise by switching to a high output medium focus.

Further, in the X-ray diagnostic apparatus 1 of the present embodiment, when the image pickup condition estimated value in the second moving image imaging is equal to or less than the determination value, the first focal size is used as the size of the X-ray focus in the second moving image imaging. Is set, and when the estimated imaging condition in the second moving image imaging is larger than the determination value, the second focal size larger than the first focal size is set as the X-ray focal size in the second moving image imaging. decide. When the estimated imaging condition in the third moving image imaging is equal to or less than the determination value, the first focal size is set as the size of the X-ray focal point in the third moving image imaging, and the imaging in the third moving image imaging is performed. When the condition estimated value is larger than the determination value, the second focal size is determined as the size of the X-ray focal point in the third moving image imaging.

In summary, the X-ray diagnostic apparatus 1 of the present embodiment, for example, in the process of step S221, when the tube voltage estimated value Vp1 in fluoroscopy with the number of fluoroscopy N is equal to or less than the threshold Vth2, the focal size in fluoroscopy with the number of fluoroscopy N is determined. When the small focus is determined and the tube voltage estimated value Vp1 in fluoroscopy with the number of fluoroscopy N is larger than the threshold value Vth2, the focal size in fluoroscopy with the number of fluoroscopy N is determined to be the middle focus.

For example, if the thickness of the subject is reduced during the previous fluoroscopy using the focal size of the midfocus, the output of the X-ray tube required to generate an X-ray image with a predetermined brightness or higher is small. Become. In such a case, according to the X-ray diagnostic apparatus 1 of the present embodiment, the tube voltage estimated value Vp1 at the small focal point becomes the threshold value Vth2 or less, and the focal size in the next fluoroscopy is set to the small focal point. As a result, when there is a margin in the output of the X-ray tube, that is, when an X-ray image having a predetermined contrast or higher can be generated even when a small focus with a small output is used, the next fluoroscopy is performed. By setting the focal size to the small focus, it is possible to generate an X-ray image having a higher resolution than when the focal size is set to the medium focus.

In addition, for example, when the thickness of the subject becomes large during the execution of the fluoroscopy immediately before using the focal size of the small focus, the X-ray tube required to generate an X-ray image having a predetermined brightness or more. The output is high and the contrast of the generated X-ray image is low. In such a case, according to the X-ray diagnostic apparatus 1 of the present embodiment, the tube voltage estimated value Vp1 at the small focal point becomes larger than the threshold value Vth2, and the focal size in the next fluoroscopy is set to the medium focal point. Therefore, in the next fluoroscopy, the required dose can be secured and the tube voltage can be suppressed by switching the focus size to the middle focus, which can increase the output of the X-ray tube compared to the small focus. Can be done. Therefore, it is possible to secure the contrast of the X-ray image and generate an X-ray image with less noise as compared with the case where the focal size of the small focus is continuously used.

Further, in the X-ray diagnostic apparatus 1 of the present embodiment, when the size of the X-ray focus in the first moving image imaging is the first focal size, the second moving image imaging is performed using the first value as a determination value. When the size of the X-ray focus in the first moving image is determined and the size of the X-ray focus in the first moving image is the second focus size, a second value different from the first value is used as a determination value. , Determine the magnitude of the X-ray focus in the second moving image imaging. When the size of the X-ray focus in the second moving image imaging is the first focal size, the size of the X-ray focus in the third moving image imaging is determined using the first value as a determination value. When the size of the X-ray focus in the second moving image imaging is the second focal size, the size of the X-ray focus in the third moving image imaging is determined using the second value as a determination value. For example, the second value is smaller than the first value.

In summary, the X-ray diagnostic apparatus 1 of the present embodiment is based on, for example, a tube voltage estimated value Vp1 and a threshold Vth1 in fluoroscopy of fluoroscopy count N when the focal size in fluoroscopy of fluoroscopy count N-1 is a small focal point. , The focal size in fluoroscopy with the number of fluoroscopy N is determined, and when the focal size in fluoroscopy with the number of fluoroscopy N-1 is the middle focus, the number of fluoroscopy is based on the tube voltage estimated value Vp1 and the threshold Vth2 in fluoroscopy with the number of fluoroscopy N-1. Determines the focal size in fluoroscopy of N. Here, the threshold value Vth2 is smaller than the threshold value Vth1.

That is, according to the X-ray diagnostic apparatus 1 of the present embodiment based on the above configuration and operation, a threshold value for determining whether or not to switch the focal size in the next fluoroscopy from the medium focus to the small focus, and a small focus to the medium focus The threshold for switching the focus size is different. Therefore, for example, even when the tube voltage estimated value Vp1 is switched between a range smaller than the threshold value Vth and a range larger than the threshold value Vth each time the previous perspective is switched to the next perspective, the center focus is used. Since the threshold value for determining the switching of the focus size to the small focus and the threshold value for determining the switching of the focal size from the small focus to the medium focus are different, it is possible to prevent the focus size from being switched each time the fluoroscopy is performed.

Further, in the X-ray diagnostic apparatus 1 of the present embodiment, the ratio of the estimated radiation dose to the upper limit of the radiation dose when the estimated imaging condition in the second moving image imaging is used as the imaging condition in the second moving image imaging. , The ratio of the estimated exposure dose to the upper limit of the exposure dose when the estimated imaging condition in the third moving image imaging is used as the imaging condition in the third moving image imaging is further calculated. Further, the size of the X-ray focus in the first moving image imaging is the first focal size, the imaging condition estimated value in the second moving image imaging is larger than the determination value, and the ratio in the second moving image imaging. Is larger than the dose determination value, the first focal size is determined as the magnitude of the X-ray focal point in the second moving image imaging. Further, the size of the X-ray focus in the second moving image imaging is the first focal size, the imaging condition estimated value in the third moving image imaging is larger than the determination value, and the ratio in the third moving image imaging. Is larger than the dose determination value, the first focal size is determined as the magnitude of the X-ray focal point in the third moving image imaging.

In summary, in the X-ray diagnostic apparatus 1 of the present embodiment, for example, the focal size in fluoroscopy with the number of fluoroscopy N-1 is small, and the tube voltage estimated value Vp1 in fluoroscopy with the number of fluoroscopy N is larger than the threshold Vth1. When the exposure limit arrival index R is equal to or less than the threshold β, the focal size in fluoroscopy with the number of fluoroscopy N is determined to be the middle focus, the focal size in fluoroscopy with the number of fluoroscopy N-1 is the small focal point, and in fluoroscopy with the number of fluoroscopy N. When the tube voltage estimated value Vp1 is larger than the threshold Vth1 and the exposure limit arrival index R is larger than the threshold β, the focal size in fluoroscopy with the number of fluoroscopy N is determined to be a small focal point.

Therefore, in the X-ray diagnostic apparatus 1 of the present embodiment, when the small focus is used in the immediately preceding fluoroscopy, the contrast of the X-ray image generated in the next fluoroscopy is low, and the medium focus is used as the focal size. The next focal size is switched to the medium focus only when a sufficient margin of the predicted exposure dose for the exposure limit when used is secured. On the other hand, the X-ray diagnostic apparatus 1 of the present embodiment has a case where the contrast of the X-ray image generated in the next fluoroscopy is low, but the margin of the predicted exposure dose with respect to the exposure limit is not sufficiently secured. Do not switch the next focus size to medium focus.

That is, according to the X-ray diagnostic apparatus 1 of the present embodiment by the above configuration and operation, the focus size is set to the central focus where the exposure dose of the subject becomes large only when the exposure dose margin is secured above a certain level. Switch. As a result, it is possible to reliably prevent the exposure dose to the subject from exceeding the exposure limit in the next fluoroscopy.

Further, the X-ray diagnostic apparatus 1 of the present embodiment includes the output of the X-ray detector 13 in the first moving image imaging executed in response to the operation to the operation unit, and information on the filter selected by the filter selection unit. Based on the above, the size of the X-ray focus in the second moving image imaging, which is executed in response to the operation to the operation unit after the first moving image imaging, is determined, and the X-ray detector 13 in the second moving image imaging. X-ray focus magnitude in the third moving image imaging, which is performed in response to an operation on the operating section after the second moving image imaging, based on the output of and the information about the filter selected by the filter selection unit. To determine.

In summary, the X-ray diagnostic apparatus 1 of the present embodiment considers the change in the target dose by considering the FPD element size in addition to the body thickness, and selects an appropriate additional filter in the next fluoroscopy. Then, an appropriate focal size in the next fluoroscopy is determined based on the imaging condition estimated value when an additional filter appropriately selected in the next fluoroscopy is used.

That is, with the above configuration and operation, according to the X-ray diagnostic apparatus 1 of the present embodiment, the X-ray condition controlled to an appropriate value according to the thickness of the subject by feedback control in the previous fluoroscopy, and the target dose. The appropriate focal size for the next fluoroscopy can be set based on an additional filter that is appropriately selected taking into account changes in. As a result, the image quality of the X-ray image generated in the next fluoroscopy is further improved.

According to at least one embodiment described above, it is possible to provide an X-ray diagnostic apparatus capable of determining an appropriate additional filter according to a target dose.

(Modified Examples of First Embodiment to Seventh Embodiment)
The processing circuit 44 may use the filter selection function 443 to select a plurality of additional filters from the filters A to D as additional filters to be used in the fluoroscopy of the number of times of fluoroscopy N. Further, the processing circuit 44 may determine by the filter selection function 443 that none of the additional filters A to D is used as the selection result of the additional filter used in the fluoroscopy of the number of fluoroscopy N.

The number of additional filters provided in the X-ray generating unit 12 may be one. In this case, an additional filter having a different thickness is used depending on the part inserted between the X-ray tube and the X-ray filter. In the filter selection process, the maximum power, the exposure limit, the SID, and the body thickness and the additional filter are used. A correspondence table showing the relationship with the thickness is used. The processing circuit 44 is inserted between the X-ray tube and the X-ray diaphragm by the filter selection function 443 based on the correspondence table, the maximum power in fluoroscopy of the number of fluoroscopy N, the exposure limit, the SID, and the body thickness. Determine the thickness of the additional filter. Then, the processing circuit 44 adjusts the portion to be inserted between the X-ray tube and the X-ray diaphragm in the additional filter based on the thickness of the additional filter determined by the drive control function 444. In this case, the processing circuit 44 that realizes the filter selection function 443 is an example of the thickness determining unit.

In addition, a plurality of configurations of the configurations of the first embodiment to the sixth embodiment may be combined. For example, the processing circuit 44 uses the filter selection function 443 to X out of a plurality of additional filters based on the FPD element size, the focal size, the maximum power, the exposure limit, and the body thickness in the fluoroscopy count N. An additional filter to be inserted in the path from the focal point of the line tube to the X-ray detector 13 may be selected, and the FPD element size, the FPD pixel size, the pixel size, the focal size, and the pulse in the fluoroscopy with the number of fluoroscopy N may be selected. Of the plurality of additional filters, an additional filter to be inserted in the path from the focal point of the X-ray tube to the X-ray detector 13 may be selected based on the rate, the maximum power, the exposure limit, and the body thickness. Further, for example, the processing circuit 44 uses the filter selection function 443 to obtain any one of the FPD pixel size, the pixel size, the field size, the focal point size, the maximum power, and the exposure limit in the fluoroscopy with the number of times of see-through N. Of the plurality of additional filters, an additional filter to be inserted in the path from the focal point of the X-ray tube to the X-ray detector 13 may be selected based on one and the body thickness.

In the filter selection process, the processing circuit 44 appropriately adjusts the information regarding the body thickness of the subject according to the change in the subject condition by the feedback control described above in fluoroscopy with the number of fluoroscopy N-1 instead of the body thickness. The X-ray conditions given may be used. The X-ray conditions appropriately adjusted according to the change in the subject condition by the feedback control described above in the fluoroscopy of the fluoroscopy count N-1 include, for example, the filter specific information at the end of the fluoroscopy of the fluoroscopic number N-1 and the tube voltage. Tube current, pulse width, AGC magnification, etc.

According to at least one embodiment described above, an appropriate additional filter can be determined according to the target dose.

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 embodiments can be implemented in various other forms, and various omissions, replacements, and changes can be made without departing from the gist of the invention. These embodiments and modifications thereof are included in the scope and gist of the invention as well as the invention described in the claims and the equivalent scope thereof.

1 ... X-ray diagnostic device 10 ... Imaging device 11 ... High voltage generator 12 ... X-ray generator 13 ... X-ray detector 14 ... C-arm 142 ... C-arm drive device 15 ... X-ray generator 30 ... Sleeper device 31 ... Base 32 ... Sleeper drive device 33 ... Top plate 34 ... Support frame 40 ... Console device 41 ... Memory 42 ... Display 43 ... Input interface 44 ... Processing circuit 441 ... System control function 442 ... Imaging condition setting function 443 ... Filter selection function 444 ... Drive control function 445 ... X-ray control function 446 ... Image generation function 447 ... Display control function Vp1 ... Tube voltage estimated value Vp2 ... Tube voltage estimated value Ip1 ... Tube current estimated value Ip2 ... Tube current estimated value Mp1 ... AGC magnification estimated value Mp2 ... AGC magnification estimated value Wp1 ... Pulse width estimated value Wp2 ... Pulse width estimated value Vth1, Vth2, β ... Threshold α1 ... Set value R ... Exposure limit arrival index

Claims (14)

An X-ray tube that generates X-rays and
An X-ray detector that detects X-rays emitted from the X-ray tube,
A plurality of filters for attenuating X-rays emitted from the X-ray tube, and
A filter drive unit that inserts at least one of the plurality of filters with respect to the X-ray path from the X-ray focal point in the X-ray tube to the X-ray detector.
Information on the size of the pixels in the X-ray detector, at least one of the size of the pixels in the X-ray image based on the output by the X-ray detector, the size of the X-ray irradiation region, and the body thickness of the subject. A filter selection unit that selects a filter to be inserted into the path from the plurality of filters based on
An X-ray diagnostic device comprising. The filter selection unit is the X-ray detector when the pixel size in the X-ray detector is large based on the pixel size in the X-ray detector and information on the body thickness of the subject. A filter having a thickness equal to or greater than the thickness of the filter selected when the pixel size is small is selected as the filter to be inserted into the path.
The X-ray diagnostic apparatus according to claim 1. The X-ray detector includes a plurality of detection elements and has a plurality of detection elements.
The filter selection unit acquires the size of pixels in the X-ray detector based on the size of the detection element.
The X-ray diagnostic apparatus according to claim 2. The X-ray detector includes a plurality of detection elements and has a plurality of detection elements.
The X-ray diagnostic apparatus according to claim 2, wherein the filter selection unit acquires the size of pixels in the X-ray detector based on the number of detection elements corresponding to one pixel of the X-ray detector. .. The filter selection unit is based on the size of the pixels in the X-ray image based on the output by the X-ray detector and the information on the body thickness of the subject, and the pixels in the X-ray image based on the output by the X-ray detector. A filter having a thickness greater than or equal to the thickness of the filter selected when the size of the pixels in the X-ray image based on the output by the X-ray detector is small when the size of the filter is large, is inserted into the path. Select as,
The X-ray diagnostic apparatus according to claim 1. Based on the size of the X-ray irradiation region and the information regarding the body thickness of the subject, the filter selection unit has a small size of the X-ray irradiation region when the size of the X-ray irradiation region is large. A filter having a thickness greater than or equal to the thickness of the filter selected in the case is selected as the filter to be inserted into the path.
The X-ray diagnostic apparatus according to claim 1. The filter selection unit includes the size of pixels in the X-ray detector, the size of pixels in an X-ray image based on the output of the X-ray detector, the size of the X-ray irradiation region, and the body thickness of the subject. The X-ray diagnostic apparatus according to any one of claims 1 to 6, wherein a filter to be inserted into the path is selected based on the information regarding the X-ray and the magnitude of the X-ray focal point. The filter selection unit
When the size of the focal point is large, a filter having a thickness equal to or larger than the thickness of the filter selected when the size of the focal point is small is selected as the filter to be inserted into the path.
The X-ray diagnostic apparatus according to claim 7. The filter selection unit includes the size of pixels in the X-ray detector, the size of pixels in an X-ray image based on the output of the X-ray detector, the size of the X-ray irradiation region, and the body thickness of the subject. The X-ray according to any one of claims 1 to 8, wherein a filter to be inserted into the path is selected based on the information regarding the X-ray tube and the pulse rate of the X-ray emitted from the X-ray tube. Diagnostic device. When the pulse rate is large, the filter selection unit selects a filter having a thickness equal to or greater than the thickness of the filter selected when the pulse rate is small as a filter to be inserted into the path.
The X-ray diagnostic apparatus according to claim 9. The filter selection unit includes the size of pixels in the X-ray detector, the size of pixels in an X-ray image based on the output of the X-ray detector, the size of the X-ray irradiation region, and the body thickness of the subject. Inserted into the path based on information about, the maximum output of the X-ray tube, the upper limit of the X-ray incident dose to the subject per unit time, and at least one of the distance between the source receiving planes. The X-ray diagnostic apparatus according to any one of claims 1 to 10, which selects a filter. An operation unit for instructing the imaging of a moving image using the X-ray tube and the X-ray detector, and
An X-ray condition determination unit that determines the conditions for X-ray irradiation by the X-ray tube,
With more
The X-ray condition determination unit
Based on the output of the X-ray detector in the first moving image imaging executed in response to the operation to the operation unit and the information about the filter inserted into the path selected by the filter selection unit, the above. After the first moving image imaging, the size of the X-ray focus in the second moving image imaging executed in response to the operation to the operation unit is determined.
Based on the output of the X-ray detector in the second moving image imaging and the information about the filter inserted into the path selected by the filter selection unit, the operation unit is reached after the second moving image imaging. Determines the magnitude of the X-ray focus in the third video capture performed in response to the operation of
The X-ray diagnostic apparatus according to any one of claims 1 to 11. The information regarding the body thickness of the subject is an estimated value of the body thickness of the subject calculated based on the X-ray condition adjusted by the feedback control or the X-ray condition adjusted by the feedback control. The X-ray diagnostic apparatus according to any one of 1 to 12. An X-ray tube that generates X-rays and
An X-ray detector that detects X-rays emitted from the X-ray tube,
A filter for attenuating X-rays emitted from the X-ray tube, which have different thicknesses depending on the portion inserted into the X-ray path from the focal point of the X-ray tube to the X-ray detector.
A filter drive unit that adjusts a portion of the filter that is inserted into the path,
Information on the size of the pixels in the X-ray detector, at least one of the size of the pixels in the X-ray image based on the output by the X-ray detector, or the size of the X-ray irradiation region, and the body thickness of the subject. And, based on, a thickness determining part that determines the thickness of the filter at the site to be inserted into the path, and
An X-ray diagnostic device comprising.