JP2017192430A - Radiation source control device, program, radiation source, and radiographic image diagnostic device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a radiographic image diagnostic device capable of suppressing radiation exposure to a subject.SOLUTION: Fluoroscopy is performed for a one-shot fluoroscopic time which means a time required from the start of the fluoroscopy to a time when a frame image related to the fluoroscopy reaches appropriate exposure by feedback control. So, even if the time taken from an instruction to start fluoroscopy to an instruction to end fluoroscopy in an operator is short, the fluoroscopy is continued until a frame is subjected to fluoroscopy with appropriate exposure. Thus, fluoroscopy is not ended before exposure becomes appropriate by the feedback control of an X-ray tube 3.SELECTED DRAWING: Figure 1

Description

  The present invention relates to a radiological image diagnostic apparatus having a fluoroscopy mode and a control apparatus included therein.

  Medical institutions are equipped with various medical devices. An example of a medical device is a radiological image diagnostic apparatus that performs radiography of a subject (see, for example, Patent Document 1).

  FIG. 12 illustrates a radiation image diagnostic apparatus having a conventional configuration. A radiographic diagnostic apparatus having a conventional configuration includes a top plate 52 on which a subject M is placed, a radiation detector 54 positioned below the top plate 52, and a radiation source 53 positioned above the top plate 52. It has.

  Some of such radiological image diagnostic apparatuses have a fluoroscopic mode. The fluoroscopy means that the subject M is displayed as a moving image with radiation. During execution of the fluoroscopic mode, the fluoroscopic image of the subject M is projected as a moving image on a monitor attached to the apparatus.

  A state in which such a radiation image diagnostic apparatus operates in the fluoroscopic mode will be described. When the operator gives an instruction to start fluoroscopy to the apparatus, the radiation source 53 is controlled to irradiate the radiation with a predetermined tube voltage and tube current. Then, the radiation source 53 irradiates the subject M on the top plate 52 with a certain dose of radiation.

  However, it is difficult to start fluoroscopy under appropriate conditions. If the thickness of the subject M is too thick than the standard, exposure becomes insufficient and the perspective moving image becomes dark. On the other hand, if the thickness of the subject M is too thin than the standard, it will be overexposed and the fluoroscopic video will become whitish. In either case, it is not possible to perform fluoroscopy with high visibility.

  Therefore, the radiological image diagnostic apparatus provided with the fluoroscopic mode has a function of feedback-controlling the radiation source 53. That is, the radiological image diagnostic apparatus is configured to sequentially monitor whether fluoroscopic exposure is appropriate based on the output of the radiation detector 54. When the apparatus determines that the exposure is insufficient, the radiation source 53 is feedback-controlled to increase the radiation dose. When the apparatus determines that the exposure is excessive, the radiation source 53 is feedback-controlled to increase the radiation dose. Is done. The conventional configuration ensures exposure adjustment by starting the fluoroscopy with a dose smaller than the radiation dose appropriate for imaging the standard-type subject and then performing feedback control of the radiation source 53 so as to gradually increase the radiation dose. I am trying to do it.

JP 2012-143443 A

However, the conventional radiographic image diagnosis apparatus has the following problems.
That is, the radiation image diagnostic apparatus having the conventional configuration is not configured to sufficiently function the feedback control of the radiation source.

  When performing fluoroscopy of the subject M, it is better that the exposure to the subject M is as small as possible. Because of this situation, fluoroscopy is often completed in a short time. Then, fluoroscopy ends before the exposure becomes appropriate by feedback control of the radiation source.

  On the monitor attached to the device, a fluoroscopic image is reflected in real time. When the fluoroscopy is finished, the last obtained moving image frame is continuously displayed on the monitor. It is difficult to make an appropriate diagnosis based on the displayed final fluoroscopic image. This is because the moving image frame displayed on the monitor is obtained in a state where exposure is not sufficiently adjusted. When such a state is reached, in order to obtain a moving image frame whose exposure has been sufficiently adjusted, the fluoroscopy must be performed again from the beginning. Then, the series of fluoroscopic operations performed previously are useless. That is, an excessive unnecessary exposure occurs because the surgeon tries to suppress the radiation exposure of the subject M. The conventional configuration is not configured in consideration of such circumstances.

  The present invention has been made in view of such circumstances, and an object thereof is to provide a radiological image diagnostic apparatus capable of suppressing radiation exposure of the subject M.

The present invention has the following configuration in order to solve the above-described problems.
That is, the radiation source control device according to the present invention includes a radiation source that irradiates radiation toward a subject, a detection unit that detects radiation that has passed through the subject, and the start and end of fluoroscopy that is a moving image display by radiation. A radiation source control device mounted on a radiological image diagnostic apparatus having an input means for allowing the surgeon to input a frame image related to fluoroscopy based on the output of the detection means when fluoroscopy is started In the radiation source control apparatus configured to feedback control the radiation source so that exposure is performed, if the time required from the instruction to start fluoroscopy to the instruction to end fluoroscopy is shorter than a predetermined time, Radiation is emitted only during the one-shot fluoroscopy time, which means the time required for the fluoroscopic frame image to be properly exposed by feedback control from the start. It is characterized in that to control the urchin the radiation source.

  [Operation / Effect] According to the present invention, it is possible to provide a radiological image diagnostic apparatus capable of suppressing radiation exposure of a subject. According to the present invention, fluoroscopy is performed during a one-shot fluoroscopy time which means a time required from the start of fluoroscopy until a frame image related to fluoroscopy is appropriately exposed by feedback control. Therefore, even if the time required from the instruction to start fluoroscopy to the instruction to end fluoroscopy is short, the fluoroscopy is continued until the frame image has an appropriate exposure. In this way, the fluoroscopy does not end before the exposure becomes appropriate by the feedback control of the radiation source.

  Further, in the above-described radiation source control device, based on the output of the detection means, an exposure that predicts the exposure of the fluoroscopic image at the end of the one-shot fluoroscopy time when the one-shot fluoroscopy time has elapsed from the start of irradiation while performing the fluoroscopy Provided with a predicting means, and when the one-shot fluoroscopic frame image is predicted not to be properly exposed at the end of the one-shot fluoroscopy, the feedback control is performed so that the frame image displayed at the one-shot fluoroscopic end time is appropriately exposed. It is more desirable to change the style.

  [Operation / Effect] According to the above-described configuration, the frame image displayed at the end of the one-shot fluoroscopy can be more reliably and appropriately exposed.

  Further, in the above-described radiation source control device, it is more desirable that the radiation irradiation of the radiation source is terminated at the time when the frame image is appropriately exposed before reaching the one-shot fluoroscopy time based on the output of the detection means.

  [Operation / Effect] According to the above-described configuration, if the frame image is appropriately exposed, radiation irradiation stops even before the one-shot fluoroscopy end point is reached. If comprised in this way, the irradiation amount of the radiation at the time of one shot fluoroscopy can be decreased more.

  Further, in the above-described radiation source control apparatus, when the time required from the start of fluoroscopy to the end of fluoroscopy by the operator is shorter than a predetermined time, it is determined that fluoroscopy is performed only during the one-shot fluoroscopy time. However, it is more desirable to include a determination unit that determines that the fluoroscopy is to be executed until the operator gives an instruction to end fluoroscopy when the time is longer than the predetermined time.

  [Operation / Effect] According to the above-described configuration, the normal fluoroscopic operation and the one-shot fluoroscopic operation can be switched by an operator's input. With such a configuration, a normal fluoroscopic operation can be easily performed.

  ADVANTAGE OF THE INVENTION According to this invention, the radiographic image diagnostic apparatus which can suppress the radiation exposure of a subject can be provided. According to the present invention, the fluoroscopy is executed only during the one-shot fluoroscopy time which means the time required from the start of fluoroscopy until the frame image related to fluoroscopy is appropriately exposed by feedback control. Therefore, even if the time required from the instruction to start fluoroscopy to the instruction to end fluoroscopy is short, the fluoroscopy is continued until the frame image has an appropriate exposure. In this way, the fluoroscopy does not end before the exposure becomes appropriate by the feedback control of the radiation source.

1 is a functional block diagram illustrating a configuration of an X-ray image diagnostic apparatus according to Embodiment 1. FIG. 2 is a functional block diagram illustrating a configuration of an X-ray tube control unit according to Embodiment 1. FIG. It is a schematic diagram explaining the feedback control which the X-ray tube control part which concerns on Example 1 performs. It is a schematic diagram explaining the feedback control which the X-ray tube control part which concerns on Example 1 performs. It is a timing chart explaining operation | movement of the X-ray tube control part which concerns on Example 1. FIG. It is a timing chart explaining operation | movement of the X-ray tube control part which concerns on Example 1. FIG. It is a schematic diagram explaining the feedback control which the X-ray tube control part which concerns on Example 1 performs. It is a schematic diagram explaining the feedback control which the X-ray tube control part which concerns on Example 1 performs. It is a schematic diagram explaining the feedback control which the X-ray tube control part which concerns on Example 1 performs. It is a schematic diagram explaining the feedback control which the X-ray tube control part which concerns on Example 1 performs. It is a timing chart explaining operation | movement of the X-ray tube control part which concerns on Example 1. FIG. It is a schematic diagram explaining the X-ray-image diagnostic apparatus of a conventional structure.

  Hereinafter, the configuration of the X-ray image diagnostic apparatus according to the first embodiment will be described. The X-ray according to Example 1 corresponds to the radiation of the present invention. FPD is an abbreviation for flat panel detector.

  FIG. 1 shows an outline of an X-ray image diagnostic apparatus according to the present invention. The X-ray diagnostic imaging apparatus according to the present invention includes a top plate 2 on which a subject M is placed, an X-ray tube 3 that irradiates X-rays provided on the top plate 2, and a lower side of the top plate 2. And an FPD 4 for detecting X-rays provided. X-rays irradiated from the X-ray tube 3 pass through the subject M and the top 2 and enter the FPD 4. The FPD 4 is configured to detect this X-ray. The X-ray tube 3 corresponds to the radiation source of the present invention, and the FPD 4 corresponds to the detection means of the present invention.

  The X-ray tube control unit 6 is configured to control the X-ray tube 3 so as to emit X-rays with a predetermined tube voltage, tube current, and pulse width. As described later, the X-ray tube control unit 6 performs feedback control of the X-ray tube 3 so that a fluoroscopic frame image is displayed at an appropriate luminance based on the output of the FPD 4 when fluoroscopy is started. It has become. The X-ray tube control unit 6 corresponds to the X-ray tube control unit of the present invention.

  The image generation unit 11 generates an X-ray image of the subject M based on the detection signal output from the FPD 4.

  The main control unit 41 is constituted by a CPU, and realizes the units 6 and 11 by executing various programs. Each unit may be realized by an arithmetic device that individually executes these units. The display unit 31 is provided for the purpose of displaying a perspective image of the subject M. The storage unit 32 stores data and the like necessary for controlling the X-ray tube 3. The console 33 is configured to input various instructions to the surgeon's device.

  The foot switch 34 is configured so that the surgeon instructs X-ray exposure. When the surgeon steps on the foot switch 34 with his / her foot, the surgeon instructs the apparatus to start X-ray exposure. . When the surgeon in this state releases his foot from the foot switch 34, the surgeon has instructed the apparatus to end X-ray exposure. The foot switch 34 is configured to allow the operator to input the start and end of fluoroscopy, which is moving image shooting by X-rays, and corresponds to the input means of the present invention.

  FIG. 2 shows the X-ray tube controller 6 which is a characteristic configuration of the present invention in more detail. The X-ray tube control unit 6 performs feedback control of the X-ray tube 3 based on the X-ray detection data sent from the FPD 4 and based on the X-ray detection data sent from the FPD 4. An exposure prediction unit 6b that predicts fluoroscopic exposure at the end of one-shot fluoroscopy, which will be described later, and a determination unit 6c that determines whether to perform one-shot fluoroscopy based on an output signal of the foot switch 34 are provided. The exposure prediction unit 6b corresponds to the exposure prediction means of the present invention. When the time required from the instruction to start fluoroscopy to the instruction to end fluoroscopy is shorter than a predetermined time, the determination unit 6c determines that the fluoroscopy is performed only during the one-shot fluoroscopy time. When it is longer than the predetermined time, it is determined that the fluoroscopy is to be executed until the operator gives an instruction to end fluoroscopy, and corresponds to the determination means of the present invention.

  FIG. 3 illustrates the feedback control of the X-ray tube 3 performed by the feedback control unit 6a. The display of the fluoroscopic image is a moving image display that displays a plurality of frame images continuously over time. Exposure is not always appropriate for the first frame image obtained after the display of the fluoroscopic image is started. This is because appropriate exposure differs depending on the physique of the subject M, and it is difficult to accurately estimate appropriate exposure before display. For the purposes of understanding the present invention, it is assumed that the initially obtained frame was underexposed. A frame acquired in an under-exposure state has a low overall contrast, making it difficult to see the subject image.

  The FPD 4 continues to send X-ray detection data to the feedback control unit 6a every time a frame image is displayed. The feedback control unit 6a monitors whether or not the current X-ray irradiation has an appropriate exposure amount based on the transmitted detection data. Whether or not the exposure is appropriate can be determined from the detected amount of X-rays in the detection data. That is, when the exposure is insufficient, the detected amount of X-rays indicated by the detection data is smaller than the appropriate amount. On the other hand, in the case of overexposure, the detected amount of X-rays indicated by the detection data is larger than the appropriate amount.

  The feedback control unit 6a changes the X-ray irradiation conditions in a stepwise manner so that the exposure amount for frame photography is appropriate based on the detection data of the FPD 4. That is, as shown in FIG. 3, in the case of underexposure, the X-ray tube 3 is controlled so as to gradually increase the X-ray dose while repeating the frame image update several times, thereby exposing the frame display. Make the amount appropriate. However, since the exposure amount is not known unless the detection data output from the FPD 4 is actually observed, it can be known only afterwards whether the exposure is appropriate. Therefore, the feedback control unit 6a performs control so that the X-ray dose increases step by step. As a result, the irradiation condition of the X-ray tube 3 can be changed while observing the state, so that the exposure amount of the frame photographing can be made appropriate safely and reliably.

  By such feedback control, the exposure amount of the displayed frame gradually becomes appropriate, and the visibility of the subject image reflected in the frame gradually improves as shown in FIG.

  FIG. 4 shows how the exposure amount of a frame changes while displaying a fluoroscopic image. The feedback control unit 6a does not change the irradiation condition of the X-ray tube 3 when the exposure amount of the frame image is appropriate. Therefore, as shown in FIG. 4, the exposure amount does not change any more after it has risen to a certain standard. In the future, the X-ray tube 3 will be controlled under the same irradiation conditions, and the fluoroscopic image will reflect the movement of the subject M based on the same visibility.

<Two purposes of performing fluoroscopy>
There are two reasons for acquiring such a fluoroscopic image. The first is a case where the subject M is simply desired to be seen through. In this case, it seems sufficient to display only one frame, but in reality, it is not known whether the exposure amount of the frame displayed first is appropriate. Therefore, in order to obtain one frame displayed with an appropriate exposure amount, it is necessary to perform fluoroscopy for a while as described with reference to FIG. In the present invention, such a fluoroscopy method is called one-shot fluoroscopy.

  The second reason is when it is desired to observe how the subject image moves. In this case, after the exposure amount of the frame image becomes appropriate, a fluoroscopic image in which the movement of the subject M is copied based on the same visibility is continuously displayed. In the present invention, such a fluoroscopy method is called normal fluoroscopy.

<The most characteristic configuration of the present invention>
The most characteristic configuration of the present invention is that when performing one-shot fluoroscopy, the fluoroscopy is surely executed until the exposure amount of the frame becomes appropriate. That is, when one-shot fluoroscopy is performed, the fluoroscopy is reliably continued during the one-shot fluoroscopy time Ts described in FIG. The one-shot fluoroscopy time Ts means the time from the start of fluoroscopy until the exposure amount of the frame becomes appropriate, and can be estimated empirically. As will be described later, the frame exposure amount may not be appropriate during the one-shot fluoroscopy time Ts, but in most cases, the frame exposure amount is appropriate when the one-shot fluoroscopy time Ts elapses from the start of fluoroscopy. It has become.

  As described above, the X-ray tube control unit 6 according to the present invention performs fluoroscopy by feedback control from the start of fluoroscopy when the time required from the fluoroscopy start instruction to the fluoroscopy end instruction by the operator is shorter than a predetermined time. The X-ray tube 3 is controlled so as to emit X-rays only during the one-shot fluoroscopy time Ts, which means the time required for the frame to be displayed with appropriate exposure. Accordingly, the X-ray irradiation stops when the one-shot fluoroscopy time Ts elapses.

  FIG. 5 illustrates the operation when the surgeon tries to perform one-shot fluoroscopy. When the surgeon is going to perform one-shot fluoroscopy, the foot switch 34 may be released immediately after stepping on with one foot. When the foot switch 34 is stepped on, an instruction to start X-ray irradiation is given from the operator at this point. When the foot switch 34 is released, the operator has instructed the end of X-ray irradiation at this point. The operator's instruction through the foot switch 34 is sent to the X-ray tube control unit 6.

  The X-ray tube control unit 6 according to the present invention does not perform the control of irradiating X-rays immediately to the X-ray tube 3 even when the foot switch 34 is stepped on. The output of the foot switch 34 is sent to the determination unit 6c to determine the operator's intention. X-rays are not emitted from the X-ray tube 3 until the determination is completed.

  When the time when the foot switch 34 is pressed is short, the determination unit 6c determines that the surgeon intends to perform one-shot fluoroscopy. Based on this determination, the X-ray tube control unit 6 controls the X-ray tube 3 so that X-ray irradiation is performed for the one-shot fluoroscopy time Ts. Whether or not the time when the foot switch 34 is pressed is short is whether the time from when the pressing of the foot switch 34 is started (pressing start time T0) to when the pressing ends is less than a predetermined time Tchk. To be judged. When the pressed time is shorter than the predetermined time Tchk, the X-ray tube control unit 6 performs X from a time point after the time Tchk has elapsed from the pressing start time point T0 (one-shot fluoroscopic start time point Ta) to perform one-shot fluoroscopy. The X-ray tube 3 is controlled so as to end the X-ray irradiation at the one-shot fluoroscopy end time T1 when the one-shot fluoroscopy time Ts has elapsed from the one-shot fluoroscopy start time Ta. While the X-ray is irradiated, the X-ray tube 3 is subjected to the feedback control described above. Then, the exposure of the frame image displayed at the one-shot fluoroscopic end time T1 becomes appropriate.

  The operation of the display unit 31 at this time will be described. After the one-shot fluoroscopy start time Ta at which the one-shot fluoroscopy is started, the current fluoroscopic image is projected on the display unit 31, and the current fluoroscopic images of the subject image are projected one after another. Among them, the last frame image is taken after the one-shot fluoroscopy time Ts elapses. This frame image is more suitable for exposure than any frame that has been projected on the display unit 31 so far. After the display of the last frame image, the one-shot perspective is finished, but the last frame is continuously displayed on the display unit 31. The surgeon can examine the state of the subject M by looking at this.

  FIG. 6 illustrates an operation when the surgeon normally performs fluoroscopy. When the surgeon normally performs fluoroscopy, the foot switch 34 may be kept depressed. When the time during which the foot switch 34 is pressed is long, the determination unit 6c determines that the surgeon normally intends to perform fluoroscopy. Based on this determination, the X-ray tube control unit 6 controls the X-ray tube 3 so that X-ray irradiation is continuously performed while the operator steps on the foot switch 34. Whether the foot switch 34 has been pressed for a long time depends on whether the time from when the foot switch 34 is pressed (pressing start time T0) to when the pressing is completed is equal to or longer than a predetermined time Tchk. To be judged. When the pressed time is longer than the predetermined time Tchk, the X-ray tube control unit 6 performs X-ray irradiation from the one-shot fluoroscopy start time Ta after the time Tchk has elapsed from the press start time T0 to perform normal fluoroscopy. The X-ray tube 3 is controlled so as to end the X-ray irradiation at a pressing end time T2 when the operator releases the foot switch 34 from the one-shot fluoroscopic start time Ta. At this time, the X-ray tube 3 receives the above-described feedback control, the exposure of the displayed frame image becomes appropriate, and the fluoroscopy is continued as it is.

  The operation of the display unit 31 at this time will be described. After the one-shot fluoroscopy start time Ta at which the one-shot fluoroscopy is started, the current fluoroscopic image is projected on the display unit 31, and the current fluoroscopic images of the subject image are projected one after another. The surgeon can examine the state of the subject M by looking at this. Among them, the last frame image is displayed after the end point T2 of pressing has elapsed. After the display of the last frame image, the one-shot perspective is finished, but the last frame is continuously displayed on the display unit 31.

<Operation of the exposure prediction unit 6b>
As described above, according to the present invention, it is possible to obtain a frame image with an appropriate exposure amount by performing one-shot fluoroscopy. However, as described above, the exposure amount of the frame image is not known until it is seen through, and the adjustment of the exposure is not always possible as expected. According to the present invention, the exposure predicting portion 6b is provided so that one-shot fluoroscopy can be performed more reliably. The exposure predicting unit 6b is configured to predict the final exposure amount if feedback control is continued as it is based on X-ray detection data output from the FPD 4 during one-shot fluoroscopy. ing. Therefore, the exposure predicting unit 6b is configured to operate from the one-shot fluoroscopy start time Ta to the one-shot fluoroscopy end time T1 after the one-shot fluoroscopy time Ts has elapsed. The exposure predicting unit 6b is configured to predict fluoroscopic exposure at the one-shot fluoroscopic end time T1, which is the time when the one-shot fluoroscopic time Ts has elapsed from the start of irradiation, based on the output of the FPD 4 during the execution of fluoroscopy.

<Operation when underexposure is expected>
FIG. 7 shows a case where the exposure prediction unit 6b predicts that the exposure amount of the frame at the one-shot fluoroscopic end time T1 is insufficient. The dotted line in FIG. 7 shows the fluctuation of the exposure amount expected by performing the feedback control. This variation in the exposure amount is expected before one-shot fluoroscopy, and when the subject M having a standard physique is seen through, the exposure amount changes almost as indicated by the dotted line. In the feedback control, the X-ray tube 3 is controlled so that the exposure amount of the frame increases stepwise. In the case of FIG. 7, if the X-ray irradiation conditions are changed four times, the exposure amount is expected to be an appropriate amount. The feedback control unit 6a is set to execute feedback control by a control method set so that the exposure amount changes as indicated by the dotted line in FIG.

  However, when the body thickness of the subject M is thicker than the standard, the number of X-rays reaching the FPD 4 is less than originally expected. Even in this case, however, the feedback control unit 6a gradually increases the output of the X-ray tube 3 by feedback control so as to reach an appropriate amount of exposure of the frame image. However, when the body thickness of the subject M is thick, the exposure amount does not become an appropriate amount even if the X-ray irradiation conditions are changed four times. This is because the exposure amount at the time of displaying the first frame image is smaller than expected, and the exposure amount that increases per change of the X-ray irradiation condition is smaller than expected. After all, if feedback control is continued as it is, the X-ray irradiation conditions must be changed nine times in total. Then, the exposure amount of the frame at the one-shot fluoroscopic end time T1 remains insufficient.

  The configuration of the present invention is devised to prevent such a situation. That is, the feedback control unit 6a according to the present invention is configured to change the feedback control method at the time t when the exposure predicting unit 6b predicts that an underexposure will occur at the one-shot fluoroscopic end time T1. That is, until the time t shown in FIG. 8, the feedback control unit 6a that has executed the feedback control in a manner corresponding to the dotted line knows that the feedback control is not progressing as expected, and at the time t, The irradiation control is changed and the feedback control mode is continued so as to increase the amount of exposure that increases per time. If the X-ray irradiation conditions are changed a total of four times by changing the feedback control mode, the exposure amount becomes an appropriate amount.

  As described above, the X-ray tube control unit 6 determines that the frame shot at the one-shot fluoroscopic end time T1 is appropriately exposed when it is predicted that the fluoroscopic frame is not properly exposed at the one-shot fluoroscopic end time T1. Change the feedback control mode so that

<Operation when overexposure is expected>
FIG. 9 shows a case where the exposure prediction unit 6b predicts that the exposure amount of the frame at the one-shot fluoroscopic end time T1 is excessive. The dotted line in FIG. 9 shows the exposure amount fluctuation expected by performing feedback control. This variation in the exposure amount is expected before one-shot fluoroscopy, and when the subject M having a standard physique is seen through, the exposure amount changes almost as indicated by the dotted line. In the case of FIG. 9, if the X-ray irradiation conditions are changed four times, the exposure amount is expected to be an appropriate amount.

  However, when the body thickness of the subject M is thinner than the standard, the number of X-rays reaching the FPD 4 is larger than originally expected. When the body thickness of the subject M is thin, if the X-ray irradiation conditions are changed four times, the exposure amount exceeds the appropriate amount. This is because the exposure amount at the time of displaying the first frame image is larger than expected, and the exposure amount that increases per change of the X-ray irradiation condition is larger than expected.

  The configuration of the present invention is devised to prevent such a situation. That is, the feedback control unit 6a according to the present invention monitors the detection data of the FPD 4 and ends the one-shot fluoroscopy when the exposure amount becomes an appropriate amount. In this case, as shown in FIG. 10, the one-shot fluoroscopy ends before the one-shot fluoroscopy time Ts elapses from the start of the one-shot fluoroscopy. In this case, the exposure amount of the frame shot last is appropriate. As described above, the X-ray tube control unit 6 ends the X-ray irradiation of the X-ray tube 3 when the frame is appropriately exposed before reaching the one-shot fluoroscopic end point based on the output of the FPD 4.

  As described above, according to the present invention, it is possible to provide an X-ray diagnostic imaging apparatus that can suppress the X-ray exposure of the subject M. According to the present invention, fluoroscopy is performed during a one-shot fluoroscopy time which means a time required from the start of fluoroscopy until a frame image related to fluoroscopy is appropriately exposed by feedback control. Therefore, even if the time required from the instruction to start fluoroscopy to the instruction to end fluoroscopy is short, the fluoroscopy is continued until the frame image has an appropriate exposure. In this way, the fluoroscopy does not end before the exposure becomes appropriate by the feedback control of the X-ray tube 3.

  The present invention is not limited to the above-described configuration, and can be modified as follows.

  (1) In the above-described configuration, when the foot switch 34 is continuously pressed beyond the one-shot fluoroscopic start time Ta, there is only a description of a configuration that shifts to normal fluoroscopy, but the present invention is not limited to this configuration. As shown in FIG. 11, when the foot switch 34 is released between the one-shot fluoroscopy start time Ta and the one-shot fluoroscopy end time T1, it is possible to continue the fluoroscopy until the one-shot fluoroscopy end time T1. . If the fluoroscopy is finished before reaching the one-shot fluoroscopy end time T1, the X-ray irradiation related to the feedback control so far becomes unnecessary exposure. Even if the one-shot fluoroscopic start time Ta is exceeded as in this modification, unnecessary exposure can be suppressed by switching the control mode to the one-shot fluoroscopy.

  (2) The X-ray tube control unit 6 according to the present invention is also realized by executing the following processing. That is, software (program) that realizes the functions of the above-described embodiments is supplied to a system or apparatus via a network or various storage media, and a computer (or CPU, MPU, or the like) of the system or apparatus reads the program. It is a process to be executed.

  (3) The X-ray tube control unit 6 according to the present invention may be provided in the X-ray tube 3.

  (4) The X-ray tube controller 6 according to the present invention may be provided in an X-ray image diagnostic apparatus.

3 X-ray tube (radiation source)
4 FPD (detection means)
6 X-ray tube controller (radiation source controller)
6b Expected exposure part (expectation prediction means)
6 Judgment part (judgment means)
34 Foot switch (input means)

Claims (7)

A radiation source for irradiating the subject with radiation;
Detection means for detecting radiation transmitted through the subject;
A radiation source control device mounted on a radiological image diagnostic apparatus having an input means for allowing an operator to input the start and end of fluoroscopy, which is a moving image display by radiation,
When the fluoroscopy is started, based on the output of the detection means, the radiation source control device configured to feedback-control the radiation source so that the frame image related to fluoroscopy is appropriately exposed,
When the time required from the instruction to start fluoroscopy to the instruction to end fluoroscopy is shorter than a predetermined time, the time required from the start of fluoroscopy until the frame image related to fluoroscopy is appropriately exposed by feedback control. A radiation source control apparatus that controls the radiation source so as to emit radiation only during a one-shot fluoroscopy time. The radiation source control apparatus according to claim 1,
Based on the output of the detection means, comprising an exposure prediction means for predicting the fluoroscopic exposure at the time of the end of the one-shot fluoroscopy when the one-shot fluoroscopy time has elapsed from the start of irradiation,
Change the feedback control mode so that the frame image taken at the end of the one-shot fluoroscopy is appropriately exposed when the one-shot fluoroscopic frame image is not expected to be at the appropriate exposure. A radiation source control device. The radiation source control device according to claim 1 or 2,
A radiation source control apparatus, wherein radiation irradiation of a radiation source is terminated when a frame image is appropriately exposed before reaching the one-shot fluoroscopy time point based on an output of the detection means. In the radiation source control device according to any one of claims 1 to 3,
When the time required from the instruction to start fluoroscopy to the instruction to end fluoroscopy is shorter than a predetermined time, it is determined that the fluoroscopy is performed only during the one-shot fluoroscopy time. A radiation source control apparatus, comprising: a determination unit that determines that the fluoroscopy is to be executed until the operator gives an instruction to end fluoroscopy.   A program causing a computer to function as each unit of the radiation source control device according to any one of claims 1 to 4.   A radiation source comprising the radiation source control device according to claim 1. A radiation image diagnostic apparatus comprising the radiation source control apparatus according to claim 1.

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