JP2012011036A - Radiographic imaging method and apparatus - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a radiographic imaging apparatus capable of photographing both a two-dimensional image and a stereoscopic vision image, in which a high-quality image is photographed as a two-dimensional image and a photographing time for a stereo image is shortened.SOLUTION: The photographing of the two-dimensional image is prohibited until a photographing interval between the last photographing of a stereoscopic vision image or two-dimensional image and this photographing of a two-dimensional image reaches a prescribed time, and each radiation image that composes the stereoscopic vision image is enabled with the photographing interval shorter than the first photographing prohibition interval prohibiting the photographing of the two-dimensional image.

Description

  The present invention shoots a radiation image that is displayed as a stereoscopic image by irradiating a subject from different shooting directions, and displays a two-dimensional image by irradiating the subject from a predetermined shooting direction. The present invention relates to a radiographic image capturing method and apparatus for capturing radiographic images.

  Conventionally, it is known that stereoscopic viewing can be performed using parallax by displaying a plurality of images in combination. Such a stereoscopically viewable image (hereinafter referred to as a stereoscopic image or a stereo image) is generated based on a plurality of images having parallax obtained by photographing the same subject from different directions.

  Such generation of stereoscopic images is used not only in the fields of digital cameras and televisions but also in the field of radiographic imaging. That is, the subject is irradiated with radiation from different directions, the radiation transmitted through the subject is detected by the radiation image detector, and a plurality of radiation images having parallax are obtained, and based on these radiation images A stereoscopic image is generated. And by generating a stereoscopic image in this way, a radiographic image with a sense of depth can be observed, and a radiographic image more suitable for diagnosis can be observed.

  On the other hand, a radiographic image capturing apparatus configured to be capable of capturing a radiographic image displayed as a two-dimensional image in the radiographic image capturing apparatus configured to be able to capture a stereoscopic image as described above has also been proposed.

  Here, one of the radiological image detectors used in the radiographic imaging apparatus as described above has been proposed using a semiconductor material, and the radiographic image detector receives radiation irradiated through a subject. In this case, a radiographic image is recorded by generating a charge, accumulating the electric charge, and acquiring the radiographic image signal representing the radiographic image by reading out the accumulated charge signal.

  In general, in the radiographic image detector as described above, information on the radiographic image taken immediately before remains, and this may become an afterimage and be superimposed on a true radiographic image. Since this afterimage becomes an artifact, it may be undesirable in image diagnosis.

  However, since this afterimage has a property of decaying exponentially with time, in order to avoid the influence of the afterimage as described above, an appropriate shooting interval in which the afterimage is simply attenuated sufficiently and the next shooting is performed. The method of setting can be considered.

JP 2008-237445 A

  However, for example, in the radiographic image capturing apparatus as described above, when capturing a radiographic image displayed as a two-dimensional image, it is desirable to set an image capturing interval enough to sufficiently attenuate the afterimage from the previous image capturing. Such a shooting interval is not necessarily required when shooting a stereo image. That is, when observing a stereo image, in order to observe a radiographic image for the left eye and a radiographic image for the right eye simultaneously, that is, to observe the first radiographic image and the second radiographic image at the same time. Even if the afterimage of the first radiographic image is displayed superimposed on the second radiographic image, the presence of the afterimage is less than when observing the radiographic image on which the afterimage is superimposed as a two-dimensional image. It is thought that it does not care.

  The two-dimensional image is used for observing the position and range of the lesion in detail, and it is necessary to display a high-quality image without the influence of the afterimage, whereas the stereo image is described above. In addition to such detailed observation, it may be used for observing a rough position such as a lesion. In such a case, it is not necessary to display a high-quality image as much as a two-dimensional image. In this sense, it is considered that the allowable range of afterimages is different between a two-dimensional image and a stereo image.

  In such photographing with different afterimage allowable ranges, if the time until the afterimage is uniformly attenuated is set, the photographing time becomes longer than necessary, and the diagnosis efficiency is lowered. It will be.

  In particular, in a radiographic imaging apparatus for breasts, it is desirable to reduce breast compression time in order to reduce the burden on the patient as much as possible, that is, to reduce imaging time as much as possible.

  In Patent Document 1, the afterimage amount of the radiation image detector is detected at a predetermined timing, and the first threshold value TH1 and the second threshold value TH2 that are set in advance prior to the next radiographic image capturing (however, TH1 > TH2) is compared with the afterimage amount. When the afterimage amount ≧ TH1, the radiographing of the radiation image is waited. When TH1> afterimage amount> TH2, the radiographic image is captured and the image is captured. A method has been proposed in which afterimage correction is performed on a radiographic image, and when TH2 ≧ afterimage amount, a radiographic image is captured and no afterimage correction is performed on the captured radiographic image. It is not considered at all that the allowable range of afterimages differs from that of a stereo image, and no corresponding shooting control is performed.

  In view of the above circumstances, the present invention is capable of capturing a high-quality image as a two-dimensional image in a radiographic image capturing apparatus capable of capturing both a two-dimensional image and a stereo image, and reducing the stereo image capturing time. An object of the present invention is to provide a radiographic imaging method and apparatus that can be shortened.

  In the radiographic image capturing method of the present invention, a plurality of radiographic images constituting a stereoscopic image of a subject are formed by irradiating the subject with radiation from different photographing directions and detecting the radiation transmitted through the subject with a radiographic image detector. In a radiographic image capturing method for capturing a two-dimensional image of a subject by irradiating the subject with radiation from a predetermined photographing direction and detecting the radiation transmitted through the subject by a radiation image detector, The two-dimensional image is prohibited from being taken until a predetermined time elapses from the stereoscopic image or the two-dimensional image to the current two-dimensional image, and the two-dimensional image is prohibited from being taken. In addition, each radiographic image constituting a stereoscopic image can be captured at a short imaging interval.

  The radiographic image capturing apparatus of the present invention is configured to be able to irradiate a subject from different shooting directions in order to shoot a stereoscopic image of the subject, and to shoot a two-dimensional image of the subject. In a radiographic imaging apparatus including a radiation irradiating unit configured to be able to irradiate radiation from a predetermined imaging direction, and a radiographic image detector that detects radiation irradiated by the radiation irradiating unit and transmitted through a subject, A shooting prohibition unit that prohibits the shooting of a two-dimensional image until a predetermined time elapses between the shooting of a visual image or a two-dimensional image and the shooting of the current two-dimensional image, and a shooting prohibition prohibited by the shooting prohibition unit A control unit that controls the radiation irradiating unit and the radiological image detector so that each radiographic image constituting a stereoscopic image can be captured at an imaging interval shorter than the interval. And said that there were pictures.

  In the radiographic image capturing apparatus of the present invention, the radiographing prohibition unit prohibits radiography of the second radiographic image until the radiographing interval between the two radiographic images constituting the stereoscopic image has elapsed for a predetermined time. The two-dimensional image capturing prohibition interval can be set to be longer than the second radiation image capturing prohibiting interval.

  Further, afterimage amount acquisition for acquiring the afterimage amount of the radiation image detector by capturing the immediately preceding stereoscopic image or two-dimensional image and the afterimage amount of the radiation image detector by capturing the first radiation image constituting the stereoscopic image. A two-dimensional image photographing prohibition interval is set based on the amount of afterimage obtained by the previous photographing when a two-dimensional image is photographed, and a three-dimensional image is photographed when a stereoscopic image is photographed. The imaging prohibition interval for the second radiation image can be set based on the afterimage amount obtained by imaging the first radiation image constituting the visual image.

  In addition, the imaging prohibition unit sets a two-dimensional image capturing prohibition interval until the afterimage amount of the immediately preceding capturing is equal to or less than the first threshold, and the afterimage by capturing the first radiation image constituting the stereoscopic image. A period until the amount becomes equal to or smaller than a second threshold value that is larger than the first threshold value can be set as an imaging prohibition interval of the second radiation image.

  In addition, the afterimage amount acquisition unit acquires the afterimage amount from the immediately preceding shooting based on the shooting conditions of the immediately preceding shooting, and the first is based on the shooting conditions of the first radiation image constituting the stereoscopic image. It is possible to acquire an afterimage amount obtained by capturing the first radiographic image.

  In addition, the afterimage amount acquisition unit acquires the afterimage amount from the immediately preceding image capturing by reading out the charge signal from the radiation image detector before capturing the current two-dimensional image, and the second image constituting the stereoscopic image. Before the radiographic image is captured, the afterimage amount obtained by capturing the first radiographic image can be acquired by reading the charge signal from the radiographic image detector.

  In addition, an imaging start receiving unit that receives an instruction to start capturing the second radiographic image constituting the stereo image and an imaging start of the current two-dimensional image is provided, and an imaging start instruction is received by the imaging start instruction receiving unit. In the case where the image is accepted, the photographing prohibition during the photographing prohibition interval can be continued.

  In addition, it is possible to provide a photographing instruction receiving unit that receives a stereoscopic image photographing instruction and a two-dimensional image photographing instruction.

  Further, it is possible to further provide a photographing prohibition interval notifying unit that informs that it is a photographing prohibition interval.

  According to the radiographic image capturing method and apparatus of the present invention, a two-dimensional image is captured until a predetermined time elapses between the immediately preceding stereoscopic image or two-dimensional image and the current two-dimensional image. In addition to the prohibition, the radiographic images constituting the stereoscopic image can be captured at an imaging interval shorter than the interval at which the imaging of the two-dimensional image is prohibited, so that a high-quality image can be taken as a two-dimensional image. At the same time, it is possible to reduce the time required to capture a stereo image.

1 is a schematic configuration diagram of a breast image radiographing display system using an embodiment of a radiographic image radiographing apparatus of the present invention. The figure which looked at the arm part of the mammography display system shown in FIG. 1 from the right direction of FIG. 1 is a block diagram showing a schematic configuration inside a computer of the breast image capturing and displaying system shown in FIG. The flowchart figure for demonstrating the effect | action of the mammography imaging display system using one Embodiment of the radiographic imaging apparatus of this invention. The figure for demonstrating the setting method of the 1st imaging | photography prohibition space | interval T1 at the time of image | photographing a two-dimensional image. The figure for demonstrating the setting method of 2nd imaging | photography prohibition space | interval T2 at the time of image | photographing a stereo image.

  Hereinafter, a breast image radiographing display system using an embodiment of a radiographic image radiographing apparatus of the present invention will be described with reference to the drawings. The breast image capturing and displaying system according to the present embodiment is configured to be capable of capturing both a stereo image and a two-dimensional image of a breast. First, a schematic configuration of the entire breast image capturing and displaying system according to the present embodiment will be described.

  As shown in FIG. 1, a breast image radiographing display system 1 of the present embodiment includes a mammography apparatus 10, a computer 8 connected to the mammography apparatus 10, a monitor 9 connected to the computer 8, and an input unit. 7.

  As shown in FIG. 1, the mammography apparatus 10 includes a base 11, a rotary shaft 12 that can move in the vertical direction (Z direction) with respect to the base 11, and can rotate. The arm part 13 connected with the base 11 is provided. FIG. 2 shows the arm 13 viewed from the right direction in FIG.

  The arm portion 13 has an alphabet C shape, and a radiation table 16 is attached to one end of the arm portion 13 so as to face the imaging table 14 at the other end. The rotation and vertical movement of the arm unit 13 are controlled by an arm controller 31 incorporated in the base 11.

  A radiographic image detector 15 such as a flat panel detector and a detector controller 33 that controls reading of a charge signal from the radiographic image detector 15 are provided inside the imaging table 14. Further, inside the imaging table 14, a charge amplifier that converts the charge signal read from the radiation image detector 15 into a voltage signal, a correlated double sampling circuit that samples the voltage signal output from the charge amplifier, A circuit board provided with an AD conversion unit for converting a voltage signal into a digital signal is also installed.

  In addition, the photographing table 14 is configured to be rotatable with respect to the arm unit 13, and even when the arm unit 13 rotates with respect to the base 11, the direction of the photographing table 14 is fixed to the base 11. can do.

  The radiation image detector 15 can repeatedly perform recording and reading of a radiation image, and may use a so-called direct type radiation image detector that directly receives radiation and generates charges. Alternatively, a so-called indirect radiation image detector that converts radiation once into visible light and converts the visible light into a charge signal may be used. As a radiation image signal reading method, a radiation image signal is read by turning on / off a TFT (thin film transistor) switch, or by irradiating reading light. It is desirable to use a so-called optical readout system from which a radiation image signal is read out, but the present invention is not limited to this, and other systems may be used.

  A radiation source 17 and a radiation source controller 32 are housed in the radiation irradiation unit 16. The radiation source controller 32 controls the timing of irradiating radiation from the radiation source 17 and the radiation generation conditions (tube current, time, tube current time product, etc.) in the radiation source 17.

  Further, in the central portion of the arm portion 13, a compression plate 18 disposed above the imaging table 14 to press and compress the breast, a support portion 20 that supports the compression plate 18, and a support portion 20 in the vertical direction ( A moving mechanism 19 for moving in the Z direction) is provided. The position of the compression plate 18 and the compression pressure are controlled by the compression plate controller 34.

  The computer 8 includes a central processing unit (CPU) and a storage device such as a semiconductor memory, a hard disk, and an SSD. The control unit 8a, the radiation image storage unit 8b, and the afterimage shown in FIG. An amount acquisition unit 8c and a photographing prohibition unit 8d are configured.

  The controller 8a outputs predetermined control signals to the various controllers 31 to 35 to control the entire system. A specific control method will be described in detail later.

  The radiation image storage unit 8b stores the radiation image signal acquired by the radiation image detector 15 in advance.

  When capturing a stereo image, the afterimage amount acquisition unit 8c performs radiographic image detector 15 by capturing the first radiographic image of the two radiographic images based on the stereo image capturing conditions. Afterimage amount remaining in the image is acquired, and when an image is captured, an afterimage that remains in the radiation image detector 15 by imaging based on the imaging conditions of the immediately preceding 2D image or stereo image Get the quantity. The method for obtaining the afterimage amount will be described in detail later.

  When capturing a stereo image, the imaging prohibiting unit 8d captures the second radiographic image after capturing the first radiographic image based on the afterimage amount acquired by the afterimage amount acquiring unit 8c. A photographing prohibition interval until permission is set, and when photographing a two-dimensional image, this time after photographing the previous two-dimensional image or stereo image based on the afterimage amount acquired by the afterimage amount acquisition unit 8c. Is set to a photographing prohibition interval until the photographing of the two-dimensional image is permitted, and a control signal is sent to the control unit 8a so that the photographing is not started even if a photographing start instruction is input by the photographer during the photographing prohibition interval. Is output. A method for setting the photographing prohibition interval will be described in detail later.

  Further, the photographing prohibiting unit 8d outputs a signal notifying the photographing prohibiting interval to the control unit 8a in order to notify the photographer of the photographing prohibiting interval, and the control unit 8a is based on this signal. A display indicating that it is a photographing prohibition interval is performed on the monitor 9.

  The input unit 7 is configured by a pointing device such as a keyboard and a mouse, for example, and receives an input of shooting conditions and a shooting start instruction by a photographer. The input unit 7 accepts a selection between a stereo image shooting mode for shooting a stereo image and a two-dimensional image shooting mode for shooting a two-dimensional image.

  The monitor 9 displays a stereo image using the two radiographic image signals output from the computer 8 when capturing a stereo image, and the radiographic image signal output from the computer 8 when capturing a two-dimensional image. Is configured to display a radiological image based on the above as a two-dimensional image.

  As a configuration for displaying a stereo image, for example, a radiographic image based on two radiographic image signals is displayed using two screens, and one of the radiographic images is observed by using a half mirror or a polarizing glass. It is possible to adopt a configuration in which a stereo image is displayed by being incident on the right eye of the observer and the other radiation image is incident on the left eye of the observer. Or, for example, two radiographic images may be displayed in a superimposed manner while being shifted by a predetermined amount of parallax, and this may be configured to generate a stereo image by observing with a polarizing glass, or a parallax barrier method and a lenticular method As described above, a stereo image may be generated by displaying two radiation images on a stereoscopically viewable 3D liquid crystal.

  In addition, the device that displays a stereo image and the device that displays a two-dimensional image may be configured separately, or may be configured as the same device if they can be displayed on the same screen.

  Next, the operation of the mammography / display system of this embodiment will be described with reference to the flowchart shown in FIG.

  First, the breast M is installed on the imaging table 14, and the breast is compressed by the compression plate 18 with a predetermined pressure.

  In the input unit 7, either a stereo image shooting mode for shooting a stereo image or a two-dimensional image shooting mode for shooting a two-dimensional image is selected by a photographer, and various shooting conditions for each shooting mode are selected. Is input (S10).

  Hereinafter, an operation when the two-dimensional image capturing mode is selected in S10 will be described. When the two-dimensional image shooting mode is selected, first, a shooting condition at the time of shooting the immediately preceding two-dimensional image or stereo image is acquired by the afterimage amount acquisition unit 8c (S12). The amount of afterimage remaining in the radiation image detector 15 is acquired (S14). Note that the shooting conditions for the previous shooting described above are set and input by the photographer at the time of shooting and are stored in a predetermined storage unit such as a memory.

  Here, as shown in FIG. 5, the residual image amount remaining in the radiation image detector 15 decreases exponentially with the lapse of time from the previous imaging. This afterimage characteristic is determined by the shooting conditions at the time of the previous shooting. The imaging conditions for determining the afterimage characteristics include, for example, the radiation quality of the radiation source 17, the mAs value, the tube voltage and the additional filter, the irradiation time of the radiation, and the like. You may make it use.

  In the afterimage amount acquisition unit 8c, various afterimage characteristics corresponding to the above-described shooting conditions are set in advance, and the afterimage amount acquisition unit 8c is based on the acquired shooting conditions immediately before shooting. Afterimage characteristics corresponding to the imaging conditions are acquired, and the afterimage characteristics are output to the imaging prohibition unit 8d.

  Next, the photographing prohibiting unit 8d sets a first photographing prohibiting interval, which is a period from the previous photographing to the photographing permission of the current two-dimensional image, based on the input afterimage characteristics. Specifically, a first threshold that is an allowable range of the afterimage amount at the time of capturing a two-dimensional image is set in advance in the imaging prohibition unit 8d, and the imaging prohibition unit 8d is based on the input afterimage characteristics. Then, the first photographing prohibition interval T1 from the time t1 of the previous photographing to the time t2 when the afterimage amount becomes the first threshold is acquired (see FIG. 5).

  Then, the shooting prohibiting unit 8d acquires the elapsed time from the previous shooting time to the current time, compares the elapsed time with the first shooting prohibited interval T1, and starts the first shooting time from the previous shooting time. It is confirmed whether or not the photographing prohibition interval T1 has passed (S18). The computer 8 is provided with a timer (not shown), and the photographing prohibiting unit 8d acquires the previous photographing time, the elapsed time up to the present time, and the like based on the time of the timer.

  If the first photographing prohibition interval T1 has already elapsed at the present time, the photographing prohibiting unit 8d causes the control unit 8a to display a message indicating that photographing is permitted at the present time on the monitor 9. Output a control signal. In the present embodiment, the message is displayed as described above, but it may be notified that photographing is permitted by other means such as lighting a lamp.

  On the other hand, if the first photographing prohibition interval T1 has not elapsed at the present time, the photographing prohibiting unit 8d controls the control unit 8a so as not to start photographing even when a photographing start instruction is input by the photographer. And a control signal is output to the control unit 8a so that a message indicating that the current time is within the first photographing prohibition interval T1, that is, photographing is prohibited, is displayed on the monitor 9. In this embodiment, a message is displayed. However, it may be notified that photographing is prohibited by other means such as lighting a lamp.

  Then, the photographing prohibiting unit 8d prohibits photographing until the first photographing prohibiting interval T1 elapses and continues displaying the photographing prohibiting message (S18, NO). When the first photographing prohibiting interval T1 elapses, photographing is performed. And a control signal is output to the control unit 8a so that the fact is displayed on the monitor 9.

  As described above, when a message for allowing photographing is displayed on the monitor 9 after the first photographing prohibition interval T1 has elapsed, a photographing start instruction is input from the input unit 7 by the photographer, and the two-dimensional image is displayed. Shooting is started (S20).

  Specifically, first, the control unit 8 a acquires information on the shooting angle input by the photographer at the input unit 7, and outputs the information on the shooting angle to the arm controller 31. Here, the description is made on the assumption that information of 0 ° is input by the photographer as information on the shooting angle, but the shooting angle of the two-dimensional image is not necessarily 0 °, and depends on the shooting purpose and the like. It is assumed that it is arbitrarily set by the photographer.

  Then, the arm controller 31 receives information on the photographing angle 0 ° output from the control unit 8a, and the arm controller 31 receives the information on the photographing angle 0 ° based on the information on the photographing angle 0 ° as shown in FIG. A control signal is output so that is in a direction perpendicular to the imaging table 14.

  Then, according to the control signal output from the arm controller 31, the arm unit 13 moves to a position where the imaging angle is 0 °, and then the control unit 8 a sends radiation to the radiation source controller 32 and the detector controller 33. A control signal is output so as to read out the radiation and the radiation image signal. In response to this control signal, radiation is emitted from the radiation source 17, a radiation image obtained by photographing the breast from the 0 ° direction is detected by the radiation image detector 15, and a radiation image signal is read by the detector controller 33. After predetermined signal processing is performed on the radiographic image signal, the radiographic image signal is stored in the radiographic image storage unit 8 b of the computer 8.

  The radiographic image signal stored in the radiographic image storage unit 8b of the computer 8 is read from the radiographic image storage unit 8b, and then subjected to predetermined signal processing and displayed on the monitor 9 as a two-dimensional image ( S22).

  Then, after the two-dimensional image is displayed as described above, when the stereo image or the two-dimensional image is continuously captured (S38, NO), the process returns to S10 again. (S38, YES).

  The above is the description of the operation when the two-dimensional image shooting mode is selected.

  Next, an operation when the stereo image shooting mode is selected in S10 will be described. When the stereo image shooting mode is selected, first, the imaging condition of the current stereo image is acquired by the afterimage amount acquisition unit 8c (S24), and based on the imaging condition, two radiations constituting the stereo image are acquired. The amount of afterimage remaining in the radiation image detector 15 is acquired by photographing the first radiation image of the images (S26).

  Here, as described above, the amount of afterimage remaining in the radiation image detector 15 by taking the first radiation image also decreases exponentially with the passage of time from the time of taking the first radiation image. Is. This afterimage characteristic is determined by the imaging conditions at the time of imaging the first radiation image. As described above, the imaging conditions for determining the afterimage characteristics include, but are not limited to, the radiation quality of the radiation source 17, the mAs value, the tube voltage and the additional filter, the irradiation time of radiation, and the like. These conditions may be used.

  In the afterimage amount acquisition unit 8c, various afterimage characteristics corresponding to the above-described imaging conditions are set in advance, and the afterimage amount acquisition unit 8c acquires the imaging conditions for imaging the acquired first radiation image. On the basis of the image capturing conditions, the afterimage characteristics corresponding to the imaging conditions are acquired, and the afterimage characteristics are output to the imaging prohibiting unit 8d.

  Next, the imaging prohibition unit 8d sets a second imaging prohibition interval that is a period from the imaging of the first radiographic image to the imaging of the second radiographic image based on the input afterimage characteristics. Set (S28). Specifically, the imaging prohibition unit 8d is preset with a second threshold value that is an allowable range of the afterimage amount when the second radiation image is captured, and the imaging prohibition unit 8d receives the input afterimage. Based on the characteristics, a second imaging prohibition interval T2 is acquired from time t1 when the first radiographic image is captured to time t2 when the afterimage amount becomes the second threshold (see FIG. 6).

  Here, when observing a stereo image as described above, in order to observe the radiographic image for the left eye and the radiographic image for the right eye at the same time, that is, the first radiographic image and the second radiographic image When the afterimage of the first radiographic image is superimposed and displayed on the second radiographic image, the radiographic image on which the afterimage is superimposed is compared with when observing as a two-dimensional image. It seems that the existence of afterimages is not a concern. That is, it can be said that the allowable afterimage amount of the second radiation image constituting the stereo image is larger than the allowable afterimage amount of the two-dimensional image.

  Therefore, in the present embodiment, the second threshold value is set to be larger than the first threshold value used when the first photographing prohibition interval T1 is set in photographing a two-dimensional image. That is, the imaging prohibition unit 8d uses the second imaging prohibition interval T2 when capturing the second radiographic image constituting the stereo image, rather than the first imaging prohibition interval T1 when capturing the two-dimensional image. Set to be shorter.

  Then, after the second imaging prohibition interval T2 is set as described above, when there is an instruction to start imaging at the input unit 7, one of the two radiographic images constituting the stereo image of the breast M is displayed. A radiographic image of the eye is taken (S30).

  Specifically, first, the control unit 8a acquires the convergence angle θ for capturing a stereo image preset by the photographer in the input unit 7, and sends the acquired information on the convergence angle θ to the arm controller 31. Output. Here, the description will be made assuming that information of θ = ± 2 ° is input by the photographer as the convergence angle information. However, the convergence angle does not necessarily have to be ± 2 °. It is assumed that it is arbitrarily set by the photographer.

  Then, the arm controller 31 receives the information on the convergence angle θ output from the control unit 8a. The arm controller 31 captures the image of the arm unit 13 based on the information on the convergence angle θ as shown in FIG. A control signal is output so as to rotate + θ ° with respect to a direction perpendicular to the table 14. That is, in the present embodiment, a control signal is output so that the arm unit 13 is rotated + 2 ° with respect to a direction perpendicular to the imaging table 14.

  Then, according to the control signal output from the arm controller 31, the arm portion 13 rotates by + 2 °. Subsequently, the control unit 8a outputs a control signal to the radiation source controller 32 and the detector controller 33 so as to perform radiation irradiation and readout of the radiation image signal. In response to this control signal, radiation is emitted from the radiation source 17, a radiation image obtained by photographing the breast from the + 2 ° direction is detected by the radiation image detector 15, and a radiation image signal is read by the detector controller 33. After predetermined signal processing is performed on the radiographic image signal, the radiographic image signal is stored in the radiographic image storage unit 8 b of the computer 8.

  Next, as described above, after the imaging of the first radiographic image is completed, the arm unit 13 rotates to the imaging angle of the second radiographic image. Specifically, as shown in FIG. 2, the arm controller 31 once returns the arm unit 13 to the initial position, and then outputs a control signal so as to rotate by −θ ° with respect to the direction perpendicular to the imaging table 14. . That is, in the present embodiment, a control signal is output so that the arm unit 13 is rotated by −2 ° with respect to a direction perpendicular to the imaging table 14. Then, according to the control signal output from the arm controller 31, the arm unit 13 rotates by -2 °.

  In parallel with the rotation operation of the arm unit 13 as described above, the imaging prohibition unit 8d acquires the elapsed time from the time when the first radiographic image was captured, and the elapsed time and the second time Is compared with the photographing prohibition interval T2, and it is confirmed whether or not the elapsed time exceeds the second photographing prohibition interval T2 (S32).

  If the second photographing prohibition interval T2 has not elapsed at the present time, the photographing prohibiting unit 8d controls the control unit 8a so as not to start photographing even when a photographing start instruction is input by the photographer. And a control signal is output to the control unit 8a so that a message indicating that the current time is within the second shooting prohibition interval T2, that is, that shooting is prohibited is displayed on the monitor 9.

  Then, the photographing prohibiting unit 8d prohibits photographing until the second photographing prohibiting interval T2 elapses and continues displaying the photographing prohibiting message (S32, NO). When the second photographing prohibiting interval T2 elapses, photographing is performed. And a control signal is output to the control unit 8a so that the fact is displayed on the monitor 9.

  As described above, when a message for permitting photographing is displayed on the monitor 9 after the second photographing prohibition interval T2, a photographing start instruction is input from the input unit 7 by the photographer, and the second sheet Radiation imaging is started (S34). If the arm unit 13 has not rotated to −2 ° at the time when the second shooting prohibition interval T2 has elapsed, the shooting start instruction by the photographer can be accepted after rotating to −2 °. To do.

  When a photographing start instruction is input by the photographer, the control unit 8a outputs a control signal to the radiation source controller 32 and the detector controller 33 so as to perform radiation irradiation and radiation image reading. In response to this control signal, radiation is emitted from the radiation source 17, a radiation image obtained by imaging the breast from the −2 ° direction is detected by the radiation image detector 15, and a radiation image signal is read by the detector controller 33, After the predetermined signal processing, the radiation image storage unit 8b of the computer 8 stores the signal.

  The two radiographic image signals stored in the radiographic image storage unit 8b of the computer 8 are read from the radiographic image storage unit 8b and then subjected to predetermined signal processing to display a stereo image on the monitor 9. (S36).

  Then, after the two-dimensional image is displayed as described above, when the stereo image or the two-dimensional image is continuously captured (S38, NO), the process returns to S10 again. (S38, YES).

  In the above embodiment, the afterimage amount acquisition unit 8c acquires the afterimage amount based on the shooting conditions. However, the present invention is not limited to this, and the afterimage amount may be acquired by other methods. For example, in the two-dimensional image capturing mode, before the current two-dimensional image is captured, an afterimage amount obtained by the previous capturing is obtained by reading out a charge signal from the radiation image detector 15 in a state in which no radiation is irradiated. In the stereo image capturing mode, the first radiographic image is read out by reading out the charge signal from the radiographic image detector 15 in a state where no radiation is irradiated before capturing the second radiographic image. The afterimage amount obtained by shooting may be acquired.

  Regarding the timing of reading from the radiation image detector 15 for acquiring the afterimage amount, for example, in the two-dimensional image capturing mode, the timing is read periodically at a preset time interval from the previous capturing. When the afterimage amount calculated based on the charged signal becomes equal to or less than the first threshold, imaging is permitted. In the stereo image capturing mode, the first radiographic image is captured in advance. It may be performed periodically at a set time interval, and photographing may be permitted when the afterimage amount calculated based on the read charge signal becomes equal to or smaller than the second threshold value.

  Alternatively, in the two-dimensional image shooting mode, when a photographer inputs an instruction to start shooting a two-dimensional image at the input unit 7, the above-described reading is performed to acquire the afterimage characteristics, and the same as in the above embodiment. When the afterimage amount becomes equal to or less than the first threshold, photographing is permitted. In the stereo image photographing mode, an instruction to start photographing the second radiation image is input by the photographer at the input unit 7. Then, after reading, the afterimage characteristics are acquired, and the image capturing may be permitted when the afterimage amount becomes equal to or less than the second threshold value, as in the above embodiment.

  As for the reading method from the radiation image detector 15 for obtaining the afterimage amount, binning reading may be performed in order to shorten the reading speed. Binning readout refers to a method in which the charge signals of a plurality of pixels are added together and read out instead of reading out the charge signals of a large number of pixels constituting the radiation image detector 15 one by one.

  Further, when the emergency photographing mode is provided in the breast image photographing display system of the above embodiment and the emergency photographing mode is selected by the photographer in the input unit 7, the stereo is performed even while photographing is prohibited by the photographing prohibiting unit 8d. An image or a two-dimensional image may be forcibly taken.

  Further, in the breast image capturing and displaying system of the above embodiment, the first capturing prohibition interval is set for each capturing of the two-dimensional image based on the afterimage amount acquired by the afterimage amount acquiring unit 8c, and the stereo image capturing is performed. Although the second photographing prohibition interval is set for each photographing, it is not always necessary to provide a photographing prohibiting period for each photographing, and the first photographing prohibiting interval and the second photographing prohibition interval are simply set based on experimental data or the like performed in advance. The photographing prohibition interval may be set in advance.

  In addition, when capturing a stereo image, the time for the arm unit 13 to rotate from the imaging angle of the first radiographic image to the imaging angle of the second radiographic image is longer than the second imaging prohibition period. If it is known in advance, imaging may be permitted from the time when the arm unit 13 has moved to the imaging angle of the second radiographic image without setting the second imaging prohibition period.

  In the above description, one embodiment of the radiographic image capturing apparatus of the present invention is applied to a breast image capturing and displaying system. However, the subject of the present invention is not limited to the breast, for example, the chest and head. The present invention can also be applied to a radiographic imaging display system for imaging.

DESCRIPTION OF SYMBOLS 1 Mammography imaging display system 7 Input part 8 Computer 8a Control part 8b Radiation image memory | storage part 8c Afterimage amount acquisition part 8d Image | photographing prohibition part 9 Monitor 10 Mammography apparatus 12 Rotating shaft 13 Arm part 14 Imaging stand 15 Radiation image detector 17 Radiation source 18 Compression plate 31 Arm controller 32 Radiation source controller 33 Detector controller 34 Compression plate controller

Claims (10)

The subject is irradiated with radiation from different photographing directions, and the radiation that has passed through the subject is detected by a radiation image detector to shoot a plurality of radiation images constituting the stereoscopic image of the subject, and the subject In a radiographic image capturing method for capturing a two-dimensional image of the subject by irradiating radiation from a predetermined imaging direction and detecting the radiation transmitted through the subject with a radiographic image detector,
Prohibiting the shooting of the two-dimensional image until a predetermined time has elapsed from the shooting of the previous stereoscopic image or the two-dimensional image until the shooting of the current two-dimensional image;
A radiographic image capturing method, wherein radiographic images constituting the stereoscopic image can be captured at an imaging interval shorter than an interval at which imaging of the two-dimensional image is prohibited. In order to shoot a stereoscopic image of a subject, the subject can be irradiated with radiation from different shooting directions, and to shoot a two-dimensional image of the subject, the subject is irradiated with radiation from a predetermined shooting direction. In a radiographic imaging device comprising: a radiation irradiator configured to be capable of irradiating; and a radiation image detector that detects radiation irradiated by the radiation irradiator and transmitted through the subject,
A photographing prohibiting unit for prohibiting photographing of the two-dimensional image until a predetermined time elapses from photographing of the immediately preceding stereoscopic image or the two-dimensional image to photographing of the current two-dimensional image;
A control unit that controls the radiation irradiating unit and the radiological image detector so that the radiographic images constituting the stereoscopic image can be photographed at a photographing interval shorter than the photographing prohibiting interval prohibited by the photographing prohibiting unit; A radiographic imaging apparatus comprising: The radiography prohibition unit prohibits radiography of the second radiographic image until a radiographing interval between two radiographic images constituting the stereoscopic image has elapsed for a predetermined time;
The radiographic image capturing apparatus according to claim 2, wherein the radiographing prohibition interval of the two-dimensional image is set to be longer than the radiographing prohibition interval of the second radiographic image. An afterimage amount of the radiation image detector obtained by photographing the immediately preceding stereoscopic image or the two-dimensional image and an afterimage amount of the radiation image detector obtained by photographing the first radiation image constituting the stereoscopic image are acquired. With an afterimage amount acquisition unit,
The photographing prohibiting unit sets a photographing prohibiting interval of the two-dimensional image based on an afterimage amount obtained by the previous photographing at the time of photographing the two-dimensional image, and at the time of photographing the stereoscopic image. 4. The imaging prohibition interval for the second radiographic image is set based on an afterimage amount obtained by imaging the first radiographic image constituting the stereoscopic image. Radiographic imaging device.   The imaging prohibition unit sets the interval until the afterimage amount of the immediately previous imaging is equal to or less than a first threshold as the imaging prohibition interval of the two-dimensional image, and captures the first radiation image constituting the stereoscopic image The radiographic image according to claim 4, wherein the afterimage amount due to is set to an imaging prohibition interval of the second radiographic image until a second threshold value that is larger than the first threshold value or less. Shooting device.   The afterimage amount acquisition unit acquires an afterimage amount from the immediately preceding shooting based on the shooting conditions of the immediately preceding shooting, and is based on the shooting conditions of the first radiation image constituting the stereoscopic image. 6. The radiographic image capturing apparatus according to claim 4, wherein an afterimage amount obtained by capturing the first radiographic image is acquired.   The afterimage amount acquisition unit acquires an afterimage amount obtained by the immediately preceding photographing by reading out a charge signal from the radiation image detector before photographing the current two-dimensional image, and constitutes the stereoscopic image. 5. The afterimage amount obtained by capturing the first radiation image is acquired by reading out a charge signal from the radiation image detector before capturing the second radiation image. Or the radiographic imaging apparatus of 5. An imaging start reception unit that receives an instruction to start capturing each radiographic image constituting the stereo image and the current two-dimensional image;
8. The photographing prohibition unit continues the prohibition of photographing during the photographing prohibition interval even when a photographing start instruction is accepted by the photographing start instruction accepting unit. The radiographic imaging apparatus of Claim 1.   9. The radiographic image capturing apparatus according to claim 2, further comprising an imaging instruction receiving unit that receives an instruction to capture the stereoscopic image and an instruction to capture the two-dimensional image.   The radiographic image capturing apparatus according to claim 2, further comprising an imaging prohibition interval notification unit that notifies that the imaging prohibition interval is reached.

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