JP2020168144A - X-ray diagnostic equipment - Google Patents

Abstract

A method for automatically determining an appropriate focal spot size. Kind Code: A1 An X-ray diagnostic apparatus according to an embodiment includes an X-ray tube, an X-ray detector, an operation unit for instructing imaging of a moving image, and an X-ray condition determination unit for determining X-ray irradiation conditions. and The X-ray condition determining unit performs second moving image imaging performed in accordance with an operation to the operation unit after the first moving image imaging, based on the output of the X-ray detector in the first moving image imaging. determining the size of the focal point of the X-ray in the second moving image capturing, based on the output of the X-ray detector in the second moving image capturing, executed in response to the operation to the operation unit after the second moving image capturing The size of the focal point of X-rays in the third moving image capturing is determined. [Selection diagram] Fig. 1

Description

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

Conventionally, in fluoroscopy using an X-ray diagnostic apparatus for circulatory organs, the operator interrupts and resumes fluoroscopy according to the progress of a device such as a catheter, so that fluoroscopy is intermittently performed multiple times during one examination. It is done in. During a single fluoroscopy, the tube voltage, tube current, and pulse width are controlled to appropriate values by feedback control as the device progresses. On the other hand, the size of the X-ray focus (hereinafter referred to as the focus size) is manually set by the operator when either continuing to use a fixed value or switching from the end of the previous fluoroscopy to the next fluoroscopy. It is set in. Along with this, for example, if the thickness of the subject changes according to the progress of the device during the previous fluoroscopy, an appropriate focal size may not be selected in the next fluoroscopy.

JP-A-2018-134417

The problem to be solved by the present invention is to automatically determine an appropriate focal size.

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 the X-ray tube and the X-ray detector. It is provided with an operation unit for instructing the imaging of a moving image using the X-ray tube, and an X-ray condition determination unit for determining the conditions for X-ray irradiation by the X-ray tube. Based on the output of the X-ray detector in the first moving image imaging executed in response to the operation to the operating unit, the X-ray condition determining unit sends the operating unit to the operating unit after the first moving image imaging. After the second moving image imaging, the magnitude of the X-ray focus in the second moving image imaging performed in response to the operation is determined, and based on the output of the X-ray detector 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 on the operation unit is determined.

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 the processing procedure of the imaging condition setting process by the X-ray diagnostic apparatus according to the second embodiment. FIG. 5 is a flowchart illustrating the processing procedure of the imaging condition setting process by the X-ray diagnostic apparatus according to the third embodiment. FIG. 6 is a flowchart illustrating the processing procedure of the imaging condition setting process by the X-ray diagnostic apparatus according to the fourth 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 arranging 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 can be 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 arranges at least one of the plurality of additional filters in 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.

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 the drive signal from the drive control function 443 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 443 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 445 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 executes the system control function 441, the imaging condition setting function 442, the drive control function 443, the X-ray control function 444, the image generation function 445, and the display control function 446 by calling and executing the program in the memory 41. It is a processor that does.

In FIG. 1, a system control function 441, an imaging condition setting function 442, a drive control function 443, an X-ray control function 444, an image generation function 445, and a display control function 446 are realized by a single processing circuit 44. Although described as those, 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 drive control function 443, the X-ray control function 444, the image generation function 445, and the display control function 446 are the system control circuit, the image pickup condition setting circuit, the drive control circuit, and X, respectively. It may be called a line control circuit, an image processing circuit, and a display control circuit, and 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, field size, distance between source image planes (Source Image Distance: hereinafter referred to as SID), and 1 pixel (1 pixel) of the X-ray image. It includes at least one of the size of the area (hereinafter, referred to as FPD pixel size) in the FPD used for the above. 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 condition includes, for example, at least one of tube current, tube voltage, focal size, pulse width, pulse rate (number of pulses per unit time), and the like.

Further, the processing circuit 44 uses the imaging condition setting function 442 to perform the next fluoroscopy based on the output of the X-ray detector 13 in the previous fluoroscopy in the inspection including the execution of the fluoroscopy a plurality of times. Determine the magnitude of the X-ray focus. 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.

The processing circuit 44 controls the C-arm drive device 142 and the sleeper drive device 32 by the drive control function 443, 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 443 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 444, 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 444 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 444 is an example of the X-ray control unit.

The processing circuit 44 generates an X-ray image by the image generation function 445, for example, based on the data output from the X-ray detector 13. 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 could not secure the detector incident dose due to the upper limit of the X-ray incident dose to the subject per unit time (hereinafter referred to as the exposure limit (Dose Limit)) and the limitation of the tube output. In this case, it is a digital gain applied to the entire image in order to secure the brightness of the X-ray image. 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 445 is an example of the image generation unit.

The processing circuit 44 reads, for example, a signal from the system control function 441 by the display control function 446, 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 446 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 443, the X-ray control function 444, and the image generation function 445.

During the execution of one fluoroscopy, the processing circuit 44 generates a plurality of X-ray images that are frames along the time series by the image generation function 445, and the X-ray image generated by the image generation function 445 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 446. At this time, the processing circuit 44 executes the AGC by the image generation function 445.

Further, the processing circuit 44 is controlled by the system control function 441 and the X-ray control function 444 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 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, in the processing circuit 44, the thickness of the subject or the structure of the internal tissue of the subject is changed by the operation of moving the top plate 33 on which the subject is placed during the execution of one fluoroscopy. At that time, the brightness and contrast of the X-ray image generated in the previous frame are detected, and the tube voltage is set so that the brightness and contrast of the X-ray image displayed in the subsequent frame satisfy a predetermined condition. , Tube current, pulse width, and AGC magnification are controlled. 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 an appropriately controlled state 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 443, the X-ray control function 444, and the image generation function 445. 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.

(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 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 S114)
When the number of fluoroscopy N is 2 or more, the processing circuit 44 acquires the imaging condition 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 S115)
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 in the fluoroscopy with the number of times of fluoroscopy N. Is calculated as close as possible to the X-ray dose (hereinafter referred to as the target dose) required for ensuring the image quality of the X-ray image (hereinafter referred to as the estimated value of the 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 outputs a 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. Is calculated. Next, the processing circuit 44 has a tube voltage estimated value Vp1, a tube current estimated value Ip1, and a pulse width in the case of performing fluoroscopy at a focal size of a small focus based on a target output and filter specific information in see-through of the number of times of see-through N. Estimated value Wp1 and AGC magnification estimated value Mp1, tube voltage estimated value Vp2, tube current estimated value Ip2, pulse width estimated value Wp2, and AGC magnification estimated value Mp2 when fluoroscopy is performed at the focal size of the central focus. Are calculated respectively. 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 S116)
The processing circuit 44 determines whether or not the focal size of fluoroscopy with the number of fluoroscopy N-1 is a small focal point based on the imaging conditions for fluoroscopy with the number of fluoroscopy N-1 acquired in step S114. When the focal size of the fluoroscopy of the number of fluoroscopy N-1 is a small focus (step S116-Yes), the process proceeds to step S117. When the fluoroscopic focus size of the fluoroscopic number N-1 is not a small focus (step S116-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 S121. Proceed to.

(Step S117)
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 S117-Yes), the process proceeds to step S118. When the tube voltage estimated value Vp1 is not equal to or less than the threshold value Vth1 (step S117-No), that is, when the tube voltage estimated value Vp1 is larger than the threshold value Vth1, the process proceeds to step S119.

(Step S118)
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 S118, the processing circuit 44 first obtains 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 estimated value 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 S118-Yes), the processing circuit 44 performs fluoroscopy for the number of fluoroscopy N with 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 S120. When the exposure limit arrival index R is larger than the threshold value β (step S118-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 S119.

(Step S119)
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 S120)
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 S121)
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 S121-Yes), the process proceeds to step S122. When the tube voltage estimated value Vp1 is not equal to or less than the threshold value Vth2 (step S121-No), that is, when the tube voltage estimated value Vp1 is larger than the threshold value Vth2, the process proceeds to step S123.

(Step S122)
The process of step S122 is the same as the process of step S119. 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 S123)
The process of step S123 is the same as the process of step S120. 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 thickness of the subject 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 S121, when the tube voltage estimated value Vp1 in fluoroscopy of the fluoroscopy count N is equal to or less than the threshold Vth2, the focal size in fluoroscopy of the fluoroscopy count 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.

(Second Embodiment)
A second embodiment will be described. This embodiment is a modification of the configuration of the first embodiment as follows. In the present embodiment, a part of the imaging condition setting process executed by the processing circuit 44 by the imaging condition setting function 442 is different from that of the first embodiment. In this embodiment, the processing circuit 44 uses the tube current estimate instead of the tube voltage estimate to determine the focal size in the next fluoroscopy. The same configuration, operation, and effect as in the first embodiment will not be described.

Hereinafter, the operation of the imaging condition setting process executed by the X-ray diagnostic apparatus 1 will be described. FIG. 4 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. The processes of steps S131 to S136, steps S138 to S140, and steps S142 to S143 in FIG. 4 are the processes of steps S111 to S116, steps S118 to S120, and steps S122 to S123 in the first embodiment, respectively. Since it is the same as the process, the description will be omitted.

(Imaging condition setting process)
(Step S137)
The processing circuit 44 determines whether or not the tube current estimated value Ip1 is equal to or less than the threshold value Is1. The threshold value Is1 is a value for determining whether or not the contrast of the generated X-ray image satisfies a predetermined condition. The threshold value Is1 is, for example, a value defined from the range of 50 to 200 mA. The threshold value Is1 may be set to a predetermined value, or may be input by the operator for each inspection. The threshold value Is1 is an example of the determination value. The threshold value Is1 is an example of the first value. When the tube current estimated value Ip1 is equal to or less than the threshold value Is1 (step S137-Yes), the process proceeds to step S138. When the tube current estimated value Ip1 is not equal to or less than the threshold value Is1 (step S137-No), that is, when the tube current estimated value Ip1 is larger than the threshold value Is1, the process proceeds to step S139.

(Step S141)
The processing circuit 44 determines whether or not the tube current estimated value Ip1 is equal to or less than the threshold value Is2. The threshold value Is2 is smaller than the threshold value Is1 by the set value α2. That is, Is2 = Is1-α2. The set value α2 is, for example, a value determined from the range of 5 to 20 mA. The set value α2 may be set to a predetermined value, or may be input by the operator for each inspection. The threshold value Is2 is an example of the determination value. Further, the threshold value Is2 is an example of the second value. When the tube current estimated value Ip1 is equal to or less than the threshold value Is2 (step S141-Yes), the process proceeds to step S122. When the tube current estimated value Ip1 is not equal to or less than the threshold value Is2 (step S141-No), that is, when the tube current estimated value Ip1 is larger than the threshold value Is2, the process proceeds to step S123.

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 calculates, for example, the tube current estimated value Ip1 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 current estimated value Ip1. 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 output of the X-ray condition in fluoroscopy with the number of fluoroscopy N, and fluoroscopy is performed based on the tube voltage estimated value Vp1. Determine the focal size in fluoroscopy with N + 1 times.

Therefore, the X-ray diagnostic apparatus 1 of the present embodiment follows 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. Determines the focus size in fluoroscopy performed on. Therefore, the same effect as that of the first embodiment can be obtained in the X-ray diagnostic apparatus 1 of the present embodiment.

(Third Embodiment)
A third embodiment will be described. This embodiment is a modification of the configuration of the first embodiment as follows. In the present embodiment, a part of the imaging condition setting process executed by the processing circuit 44 by the imaging condition setting function 442 is different from that of the first embodiment. In the present embodiment, the processing circuit 44 uses the pulse width estimate instead of the tube voltage estimate to determine the focal size in the next fluoroscopy. The same configuration, operation, and effect as in the first embodiment will not be described.

Hereinafter, the operation of the imaging condition setting process executed by the X-ray diagnostic apparatus 1 will be described. FIG. 5 is a flowchart showing an example of a procedure of imaging condition setting processing executed by the X-ray diagnostic apparatus 1 according to the present embodiment. The processes of steps S151 to S156, steps S158 to S160, and steps S162 to S163 in FIG. 5 are the processes of steps S111 to S116, steps S118 to S120, and steps S122 to S123 in the first embodiment, respectively. Since it is the same as the process, the description will be omitted.

(Imaging condition setting process)
(Step S157)
The processing circuit 44 determines whether or not the pulse width estimated value Wp1 is equal to or less than the threshold value Wth1. The threshold value Wth1 is a value for determining whether or not the contrast of the generated X-ray image satisfies a predetermined condition. The threshold value Wth1 is, for example, a value defined from the range of 10 to 20 ms. A predetermined value may be set for the threshold value Wth1, and the threshold value Wth1 may be input by the operator for each inspection. The threshold value Wth1 is an example of a determination value. The threshold value Wth1 is an example of the first value. When the pulse width estimated value Wp1 is equal to or less than the threshold value Wth1 (step S157-Yes), the process proceeds to step S158. When the pulse width estimated value Wp1 is not equal to or less than the threshold value Wth1 (step S157-No), that is, when the pulse width estimated value Wp1 is larger than the threshold value Wth1, the process proceeds to step S160.

(Step S161)
The processing circuit 44 determines whether or not the pulse width estimated value Wp1 is equal to or less than the threshold value Wth2. The threshold value Wth2 is smaller than the threshold value Wth1 by the set value α3. That is, Wth2 = Wth1-α3. The set value α3 is, for example, a value determined from the range of 3 to 5 ms. The set value α3 may be set to a predetermined value, or may be input by the operator for each inspection. The threshold value Wth2 is an example of a determination value. The threshold value Wth2 is an example of the second value. When the pulse width estimated value Wp1 is equal to or less than the threshold value Wth2 (step S161-Yes), the process proceeds to step S162. When the pulse width estimated value Wp1 is not equal to or less than the threshold value Wth2 (step S161-No), that is, when the pulse width estimated value Wp1 is larger than the threshold value Wth2, the process proceeds to step S163.

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 calculates, for example, the pulse width estimated value Wp1 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 current estimated value Ip1. The focal size in fluoroscopy with the number of fluoroscopy N is determined, the pulse width estimated value Wp1 in fluoroscopy with the number of fluoroscopy N + 1 is calculated based on the output of the X-ray condition in fluoroscopy with the number of fluoroscopy N + 1, and fluoroscopy is performed based on the tube voltage estimated value Vp1. Determine the focal size in fluoroscopy with N + 1 times.

Therefore, the X-ray diagnostic apparatus 1 of the present embodiment follows 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. Determines the focus size in fluoroscopy performed on. Therefore, the same effect as that of the first embodiment can be obtained in the X-ray diagnostic apparatus 1 of the present embodiment.

(Fourth Embodiment)
A fourth embodiment will be described. This embodiment is a modification of the configuration of the first embodiment as follows. In the present embodiment, a part of the imaging condition setting process executed by the processing circuit 44 by the imaging condition setting function 442 is different from that of the first embodiment. In this embodiment, the processing circuit 44 uses the AGC magnification estimate instead of the tube voltage estimate to determine the focal size in the next fluoroscopy. The same configuration, operation, and effect as in the first embodiment will not be described.

Hereinafter, the operation of the imaging condition setting process executed by the X-ray diagnostic apparatus 1 will be described. FIG. 6 is a flowchart showing an example of a procedure of imaging condition setting processing executed by the X-ray diagnostic apparatus 1 according to the present embodiment. The processes of steps S171 to S176, steps S178 to S180, and steps S182 to S183 in FIG. 6 are the processes of steps S111 to S116, steps S118 to S120, and steps S122 to S123 in the first embodiment, respectively. Since it is the same as the process, the description will be omitted.

(Imaging condition setting process)
(Step S177)
The processing circuit 44 determines whether or not the AGC magnification estimated value Mp1 is equal to or less than the threshold value Mth1. The threshold value Mth1 is a value for determining whether or not the noise in the generated X-ray image satisfies a predetermined condition. The threshold value Mth1 is, for example, a value defined from the range of 110 to 200%. A predetermined value may be set for the threshold value Mth1, and the threshold value Mth1 may be input by the operator for each inspection. The threshold value Mth1 is an example of a determination value. The threshold value Mth1 is an example of the first value. When the AGC magnification estimated value Mp1 is equal to or less than the threshold value Mth1 (step S177-Yes), the process proceeds to step S178. When the AGC magnification estimated value Mp1 is not equal to or less than the threshold value Mth1 (step S177-No), that is, when the AGC magnification estimated value Mp1 is larger than the threshold value Mth1, the process proceeds to step S179.

(Step S181)
The processing circuit 44 determines whether or not the AGC magnification estimated value Mp1 is equal to or less than the threshold value Mth2. The threshold value Mth2 is smaller than the threshold value Mth1 by the set value α4. That is, Mth2 = Mth1-α4. The set value α4 is, for example, a value determined from the range of 5 to 20%. The set value α4 may be set to a predetermined value, or may be input by the operator for each inspection. The threshold value Mth2 is an example of the determination value. The threshold value Mth2 is an example of the second value. When the AGC magnification estimated value Mp1 is equal to or less than the threshold value Mth2 (step S181-Yes), the process proceeds to step S182. When the AGC magnification estimated value Mp1 is not equal to or less than the threshold value Mth2 (step S181-No), that is, when the AGC magnification estimated value Mp1 is larger than the threshold value Mth2, the process proceeds to step S183.

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 calculates, for example, the AGC magnification estimated value Mp1 in fluoroscopy with the fluoroscopy count N based on the X-ray condition in fluoroscopy with the fluoroscopy count N-1, and is based on the AGC magnification estimated value Mp1. The focal size in fluoroscopy with the number of fluoroscopy N is determined, the AGC magnification estimated value Mp1 in fluoroscopy with the number of fluoroscopy N + 1 is calculated based on the output of the X-ray condition in fluoroscopy with the number of fluoroscopy N + 1, and fluoroscopy is performed based on the estimated AGC magnification value Mp1. Determine the focal size in fluoroscopy with N + 1 number of times.

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 noise changes the appropriate focal size to generate an X-ray image that satisfies the predetermined condition, the feedback control An appropriate focal size for the next fluoroscopy can be automatically set based on X-ray conditions controlled to an appropriate value according to the thickness of the subject. This improves the image quality of the X-ray image generated in the next fluoroscopy.

Further, the X-ray diagnostic apparatus 1 of the present embodiment reduces the focal size in fluoroscopy of the number of fluoroscopy N when the estimated AGC magnification Mp1 in fluoroscopy of the number of fluoroscopy N is equal to or less than the threshold Mth2 in the process of step S181, for example. When the focal point is determined and the AGC magnification estimated value Mp1 in fluoroscopy with the number of fluoroscopy N is larger than the threshold Mth2, the focal size in fluoroscopy with the number of fluoroscopy N is determined to be the middle focus.

For example, if an X-ray image with a predetermined brightness or higher cannot be generated even when the output of the X-ray tube is used to the maximum, the thickness of the subject becomes thick during the previous fluoroscopy using the focal size of the medium focus. When it becomes smaller, the AGC magnification required to generate an X-ray image having a predetermined brightness or more becomes smaller. In such a case, according to the X-ray diagnostic apparatus 1 of the present embodiment, the AGC magnification estimated value Mp1 at the small focal point becomes the threshold value Mth2 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 brightness and a small noise can be generated even when a small focus having a small output is used, the X-ray image can be generated. By setting the focal size in the next perspective to a small focal point, it is possible to generate an X-ray image having a higher resolution than when the focal size is set to a medium focal point.

Further, for example, when it is not possible to generate an X-ray image having a predetermined brightness or more even when the output of the X-ray tube is used to the maximum, the subject is subjected to the previous fluoroscopy using the focal size of the small focus. As the thickness increases, the AGC magnification required to generate an X-ray image having a predetermined brightness or higher increases, and the noise in the generated X-ray image increases. In such a case, according to the X-ray diagnostic apparatus 1 of the present embodiment, the AGC magnification estimated value Mp1 at the small focal point becomes larger than the threshold value Mth2, 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 AGC magnification can be suppressed by switching the focal size to the medium focal point, which can increase the output of the X-ray tube as compared with the small focal point. Can be done. Therefore, it is possible to secure the brightness 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.

(Modified Examples of First Embodiment to Fourth Embodiment)
The imaging condition setting process executed in step S101 is executed during moving image imaging in fluoroscopy, and the focal size in the next fluoroscopy is determined based on the current imaging conditions in the running fluoroscopy. Then, the focal size is switched based on the focal size determined in the imaging condition setting process between the end of the performing fluoroscopy and the start of the next fluoroscopy. In this case, the fluoroscopy during execution corresponds to the first moving image imaging or the second moving image imaging, and the fluoroscopy executed after the running fluoroscopy corresponds to the second moving image imaging or the third moving image imaging. To do.

Further, in the processing of step S117, step S137, step S157, and step S177, the imaging condition estimation value of the middle focus may be used instead of the imaging condition estimation value of the small focus, and the small focus and the middle focus are used. Imaging condition estimates when different different focal sizes are used may be used. Similarly, in the processing in step S121, step S141, step S161, and step S181, the medium focus imaging condition estimation value may be used instead of the small focus imaging condition estimation value, and the small focus and the middle focus may be used. May use the imaging condition estimates when other different focal sizes are used.

For example, when fluoroscopy is performed in the first imaging mode with a large resolution using a small focal size, compared with the case where fluoroscopy is performed in a second imaging mode with a small resolution using a large focal size, the X-ray tube Since the output upper limit becomes smaller, the output of the X-ray tube tends to reach the maximum output. Therefore, even if the thickness of the subject changes during the execution of fluoroscopy immediately before, the estimated tube voltage value is unlikely to change. Therefore, the type of the imaging condition estimation value used for the determination may be selected according to the resolution of the X-ray image generated in the next fluoroscopy. For example, when generating an X-ray image having the first resolution, the focus size in the next perspective is selected by using the AGC magnification estimated value as in the fourth embodiment, and the first resolution is generated. In the case of generating an X-ray image having a higher resolution, the focal size in the next perspective may be selected using the tube voltage estimate as in the first embodiment. The resolution of the X-ray image generated in the next fluoroscopy may be acquired, for example, by inputting the setting of the imaging mode by the operator, or may be automatically acquired from the memory 41 or the like.

The focus size may be switched by controlling the control grid electrodes that can continuously adjust the focus size. In this case, the X-ray generating unit 12 is a grid-controlled discharge tube including an anode, a cathode, and a control grid electrode, and only one filament is provided on the tube. The processing circuit 44 determines the value of the next focal size in the next fluoroscopy by the imaging condition setting function 442. Then, the processing circuit 44 controls the control grid electrode by the X-ray control function 444 based on the determined size of the X-ray focal point. Specifically, the processing circuit 44 controls the control grid electrodes so that the focal size becomes a determined value.

The "output of the X-ray detector" used to determine the size of the X-ray focus by the imaging condition setting function 442 is a non-destructive reading of a part or all the pixels of the X-ray detector 13. Any information other than the X-ray image can be used as long as the information reflects the X-ray dose detected by the X-ray detector, such as the result (that is, the signal corresponding to the total accumulated charge of some or all the pixels). Good.

According to at least one embodiment described above, an appropriate focus size can be automatically set.

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 ... Drive control function 444 ... X-ray control function 445 ... Image generation function 446 ... Display control function Vp1 ... Tube voltage estimated value Vp2 ... Tube voltage estimated value Ip1 ... Tube current estimated value Ip2 ... Tube current estimated value Wp1 ... Pulse width estimated value Wp2 ... Pulse width estimation Value Mp1 ... AGC magnification estimated value Mp2 ... AGC magnification estimated value Vth1, Vth2, Is1, It2, Wth1, Wth2, Mth1, Mth2, β ... Threshold α1, α2, α3, α4 ... Set value R ...

Claims (15)

An X-ray tube that generates X-rays and
An X-ray detector that detects X-rays emitted from the X-ray tube,
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
The X-ray condition determination unit
Based on the output of the X-ray detector in the first moving image imaging performed in response to the operation on the operation unit, the operation is executed in response to the operation on the operation unit after the first moving image imaging. Determine the size of the X-ray focus in the video imaging of 2
Based on the output of the X-ray detector 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. Determine the
X-ray diagnostic equipment. The X-ray condition determination unit
Based on the output of the X-ray detector at the end of the first moving image imaging, the size of the X-ray focus at the start of the second moving image imaging is determined.
Based on the output of the X-ray detector at the end of the second moving image imaging, the magnitude of the X-ray focus at the start of the third moving image imaging is determined.
The X-ray diagnostic apparatus according to claim 1. The X-ray condition determination unit
Based on the output of the X-ray detector in the first moving image imaging, an imaging condition estimated value that satisfies the condition regarding the target output when a specific X-ray focus size is used for the second moving image imaging. Is calculated, and the size of the focal point of the X-ray in the second moving image imaging is determined based on the imaging condition estimated value in the second moving image imaging.
Based on the output of the X-ray detector in the second moving image imaging, the imaging condition estimated value is calculated for the third moving image imaging, and the imaging condition estimated value in the third moving image imaging is used. Determines the magnitude of the X-ray focal point in the third moving image imaging.
The X-ray diagnostic apparatus according to claim 1 or 2. The X-ray condition determination unit
When the imaging condition estimated value in the second moving image imaging is equal to or less than the determination value, the first focal size is set as the focal size of the X-ray in the second moving image imaging, and the second moving image is captured. When the estimated imaging condition in imaging is larger than the determination value, a second focal size larger than the first focal size is determined as the focal size of the X-ray in the second moving image imaging.
When the imaging condition estimated value in the third moving image imaging is equal to or less than the determination value, the first focal size is set as the focal size of the X-ray in the third moving image imaging, and the third moving image is captured. When the image pickup condition estimated value in the moving image imaging is larger than the determination value, the second focal size is determined as the focus size of the X-ray in the third moving image imaging.
The X-ray diagnostic apparatus according to claim 3. The X-ray condition determination unit
When the size of the X-ray focus in the first moving image imaging is the first focal size, the size of the X-ray focus in the second moving image imaging is set using the first value as the determination value. When the size of the X-ray focus in the first moving image imaging is the second focal size, the second value different from the first value is used as the determination value, and the second value is used. Determine the size of the focal point of the X-ray in the moving image imaging of
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 set using the first value as the determination value. When the size of the focal point of the X-ray in the second moving image imaging is the second focal size, the X in the third moving image imaging is set using the second value as the determination value. Determine the size of the focus of the line,
The X-ray diagnostic apparatus according to claim 4. The X-ray diagnostic apparatus according to claim 5, wherein the second value is smaller than the first value. The X-ray condition determination unit
The ratio of the estimated exposure dose to the upper limit of the exposure dose when the estimated imaging condition in the second moving image imaging is used as the imaging condition in the second moving image imaging, and the imaging in the third moving image imaging. The ratio of the estimated radiation dose to the upper limit of the radiation dose when the estimated condition was used as the imaging condition in the third moving image imaging was further calculated.
The size of the X-ray focal point in the first moving image imaging is the first focal size, the estimated imaging condition in the second moving image imaging is larger than the determination value, and the second moving image is captured. When the ratio in the moving image imaging is smaller than the dose determination value, the second focal size is determined as the size of the X-ray focus in the second moving image imaging.
The size of the X-ray focal point in the second moving image imaging is the first focal size, the estimated imaging condition in the third moving image imaging is larger than the determination value, and the third moving image is captured. When the ratio in the moving image imaging is smaller than the dose determination value, the second focal size is determined as the size of the X-ray focus in the third moving image imaging.
The X-ray diagnostic apparatus according to any one of claims 4 to 6. The imaging condition estimated value includes a tube voltage estimated value that satisfies the condition for the target output, a tube current estimated value that satisfies the condition for the target output, a pulse width estimated value that satisfies the condition for the target output, and the target. The X-ray diagnostic apparatus according to any one of claims 3 to 7, which comprises at least one of the AGC magnification estimates satisfying the above conditions for output. The X-ray condition determination unit
Based on the X-ray focal size, tube voltage, tube current and pulse width, AGC magnification, and filter specific information acquired based on the output of the X-ray detector in the first moving image imaging, the second The estimated value of the imaging condition in moving image imaging is calculated,
Based on the X-ray focal size, tube voltage, tube current and pulse width, AGC magnification, and filter specific information acquired based on the output of the X-ray detector in the second moving image imaging, the third The estimated value of the imaging condition in moving image imaging is calculated.
The X-ray diagnostic apparatus according to any one of claims 3 to 8. The X-ray condition determination unit
For each of the plurality of focal sizes having different X-ray focal sizes, the imaging condition estimated value in the second moving image imaging is calculated and corresponds to the focal size determined as the X-ray focal size. The estimated image quality is determined as the image pickup condition in the second moving image imaging,
For each of the plurality of focal sizes having different X-ray focal sizes, the imaging condition estimated value in the third moving image imaging is calculated and corresponds to the focal size determined as the X-ray focal size. The imaging condition estimated value is determined as an imaging condition in the third moving image imaging.
The X-ray diagnostic apparatus according to any one of claims 3 to 9. Further provided is an X-ray control unit that selects a filament to be used from a plurality of filaments provided on the bulb of the X-ray tube based on the size of the focal point of the X-ray determined by the X-ray condition determination unit. , The X-ray diagnostic apparatus according to any one of claims 1 to 10. A control grid electrode capable of adjusting the size of the focal point of the X-ray generated from the X-ray tube, and
An X-ray control unit that controls the control grid electrodes based on the magnitude of the X-ray focal point determined by the X-ray condition determination unit,
The X-ray diagnostic apparatus according to any one of claims 1 to 10, further comprising. The X-ray condition determination unit
In the first moving image imaging and the second moving image imaging, at least of the X-ray irradiation conditions and the gain applied to the X-ray image in the subsequent frame based on the output of the X-ray detector in the previous frame. Control to set one
Through the conditions of X-ray irradiation in the first moving image imaging, the magnitude of the X-ray focus in the second moving image imaging is determined based on the output of the X-ray detector in the first moving image imaging. Decide and
Through the conditions of X-ray irradiation in the second moving image imaging, the magnitude of the X-ray focus in the third moving image imaging is determined based on the output of the X-ray detector in the second moving image imaging. decide,
The X-ray diagnostic apparatus according to any one of claims 1 to 12. The X-ray condition determination unit
Based on the X-ray image generated based on the output of the X-ray detector in the first moving image imaging, the size of the focal point of the X-ray in the second moving image imaging is determined.
The magnitude of the X-ray focal point in the third moving image imaging is determined based on the X-ray image generated based on the output of the X-ray detector in the second moving image imaging.
The X-ray diagnostic apparatus according to any one of claims 1 to 13. The X-ray condition determination unit
Based on the completion of the first moving image imaging, the size of the focal point of the X-ray in the second moving image imaging is determined.
Based on the completion of the second moving image imaging, the size of the focal point of the X-ray in the third moving image imaging is determined.
The X-ray diagnostic apparatus according to any one of claims 1 to 14.