JP2014221136A - Radiographic system - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a radiographic system having the merit of a radiographic system that is able to virtually display a field of radiation emission by means of a field of visible light emission, and the merit of a radiographic system that is able to display a field of radiation emission by means of a camera 3 as a photographic image.SOLUTION: A radiographic system comprises: a limiting blade 204 for forming an aperture 203 through which radiation from a radiation generating device 1 is passed, and restricting, by means of the size of the aperture 203, a field of radiation emitted to a test body 7; a visible-light source 202 that virtually displays, as a field of visible light emission, the field of radiation emission by emitting visible light via the aperture 203 of the limiting blade 204; a camera 3 for photographing the test body 7; and a display section 4 that displays an image photographed by the camera 3. The radiographic system is able to simultaneously carry out the photographing of the test body 7 by the camera 3 and the formation of the field of visible light emission by the visible-light source 202.

Description

  The present invention relates to a radiation imaging system including a restriction blade that regulates a radiation irradiation field on a subject and a visible light source that simulates and displays the radiation irradiation field as a visible light irradiation field.

  The radiation generating apparatus usually includes a radiation generating apparatus having a built-in radiation generating tube and a movable diaphragm provided in front of the radiation transmitting window of the radiation generating apparatus. The movable diaphragm has a radiation irradiation field adjustment function that shields a portion unnecessary for imaging among the radiation emitted through the radiation transmission window of the radiation generator and reduces the exposure of the subject. The adjustment of the radiation field is performed by adjusting the size of the opening formed by the limiting blade and through which the radiation passes. This movable diaphragm is usually provided with a visible light source that simulates and displays the radiation irradiation field by the visible light irradiation field and allows the range of the radiation irradiation field to be confirmed with the naked eye before photographing. In general, the visible light source is provided with a reflection mirror capable of transmitting radiation between the radiation generator and the restricting blade, and symmetrical with the radiation focal point of the radiation generator with respect to the reflection surface of the reflection mirror. In the position.

  On the other hand, as disclosed in Patent Document 1, a camera that captures an image of a subject through the opening of the restriction blade is provided at the position of the visible light source instead of the visible light source, and an image captured by the camera is displayed on the display unit. There is known a radiation imaging system that can be displayed by the user. In the case of this radiation imaging system, the captured image itself displayed on the display unit displays the radiation irradiation field, and the radiation irradiation field can be confirmed on the display unit.

Japanese Patent Laid-Open No. 6-217773

  In the case of a radiation imaging system equipped with a camera as disclosed in Patent Document 1, the size of the radiation field is set on the display unit, and the size of the aperture is set by driving the limiting blade according to the setting. It is possible to adjust according to the field. For this reason, it is possible to adjust and confirm the radiation field from outside the imaging room away from the subject, and it is not necessary to reciprocate inside and outside the imaging room for confirmation of the radiation field, so that the examination time can be shortened. . In addition, since the radiation field immediately before imaging can be confirmed, there is an advantage that it is easy to prevent misaligned imaging due to movement when the subject is a person or an animal.

  However, in the case of the radiation imaging system disclosed in Patent Document 1, since the visible light source is not provided, the radiation irradiation field cannot be directly visually recognized regardless of the display unit. Therefore, when the subject is a person, there is a problem that the radiation field is appropriate or anxiety may be given. In addition, since the radiation field can be confirmed only as an image on the display unit, for example, when a subject with a large body thickness is used as a subject, the penumbra may become large and the radiation irradiation range may become unclear. is there. In addition, since the entire image captured through the aperture of the limiting blade is displayed as a radiation field, in order to determine the radiation field while observing the surrounding area other than the radiation field, the limiting blade must be fully opened for each imaging. In addition, there is a problem that it is difficult to observe the surrounding area.

  On the other hand, in the case of a radiation imaging system that simulates and displays a radiation irradiation field with a visible light irradiation field by a visible light source, there is an advantage that there is no such problem as described above. On the other hand, since it is necessary to visually check and confirm the visible light irradiation field near the subject, there is a problem that it is difficult to check the radiation irradiation field just before imaging because it has to travel back and forth inside the imaging room. .

  The present invention provides a radiation imaging system that combines the advantages of a radiation imaging system that can simulate and display a radiation field with a visible light field and the advantages of a radiation imaging system that can display the radiation field as a captured image by a camera. Objective.

For the above purpose, a first aspect of the present invention is to form an opening through which the radiation from the radiation generator passes, and restrict the radiation irradiation field to the subject according to the size of the opening; In a radiation imaging system comprising a visible light source that simulates and displays the radiation irradiation field as a visible light irradiation field by irradiating visible light through the opening,
A camera for photographing the subject and a display unit for displaying an image photographed by the camera, and capable of simultaneously performing photographing of the subject by the camera and formation of the visible light irradiation field by the visible light source The present invention provides a radiation imaging system characterized by the above.

According to a second aspect of the present invention, there is provided an aperture that allows the radiation from the radiation generator to pass therethrough, a restriction blade that regulates a radiation irradiation field to the subject according to the size of the opening, and the opening of the restriction blade. In a radiation imaging system including a visible light source that simulates and displays the radiation field as a visible light field by irradiating visible light through
A camera for photographing the subject; and a display unit for displaying an image photographed by the camera, wherein the camera is provided at a position where the subject can be photographed without passing through the opening of the restriction blade. The radiation imaging system characterized by the above is provided.

  The radiation imaging system of the present invention has both a visible light source for simulating and displaying a radiation irradiation field as a visible light irradiation field, and a camera. The camera in the present invention basically displays the visible light field as a part of the image, thereby displaying the visible light field on the display unit, thereby enabling adjustment of the radiation field. ing.

  According to the radiation imaging system of the present invention, based on the visible light irradiation field displayed on the display unit, the radiation irradiation field is set on the display unit, and the size of the opening is set by driving the limiting blade according to the setting. It is possible to adjust to the radiation field. For this reason, it is possible to adjust and confirm the radiation field from outside the imaging room away from the subject, shorten the examination time, and confirm the radiation field immediately before imaging. Further, since the radiation imaging system according to the present invention displays the radiation irradiation field in a simulated manner with the visible light irradiation field, the radiation irradiation field can be directly visually recognized. For this reason, for example, even if a person with a large body thickness is used as the subject, the penumbra can be directly confirmed visually, so that it is possible to prevent the radiation irradiation range from becoming unclear. Furthermore, since the display unit can display the entire area including the visible light irradiation field, the radiation irradiation field can be determined while observing the peripheral region.

It is a figure which shows the radiography system which concerns on the 1st example of this invention. It is a figure which shows an example of the display part in the radiography system of this invention. It is a sequence diagram which shows the operation | movement procedure of the radiography system of this invention. It is a figure which shows the other example of the radiography system of this invention, (a) is a 2nd example, (b) is a 3rd example, (c) is a figure which shows a 4th example.

  Hereinafter, the present invention will be described with reference to the drawings. In the drawings referred to below, the same reference numerals indicate the same components.

  First, a radiation imaging system according to a first example of the present invention will be described with reference to FIGS.

  The radiation imaging system according to the present invention includes a radiation generation apparatus 1, a movable diaphragm 2, a camera 3, a display unit 4, a radiation detection apparatus 5, and a system control apparatus 6.

  The radiation generation apparatus 1 includes a radiation generation tube 101 and a drive circuit 102 for driving the radiation generation tube 101. Although not shown in the drawing, the radiation generation tube 101 includes an electron source and a radiation generation target that generates radiation when irradiated with electrons. Radiation generated from the radiation generation target by being irradiated with electrons from the electron source is emitted to the outside of the radiation generation apparatus 1 through a radiation transmission window (not shown). As the radiation generation tube 101, either a reflection type radiation generation tube or an eight-day type radiation generation tube can be used, but a transmission type radiation generation tube capable of preventing the effects of heel effect and shading is preferable.

  The radiation emitted from the radiation generator 1 is applied to the subject 7 through the movable diaphragm 2 provided at the radiation emission position of the radiation generator 1. The movable diaphragm 2 includes a reflection mirror 201 provided across the irradiation path of the radiation applied to the subject 7, and a visible light source 202 for displaying the radiation irradiation field on the subject 7 as a visible light irradiation field. And. In addition, a restriction blade 204 is also provided for forming the opening 203 through which radiation is transmitted in a variable size.

  The reflection mirror 201 can transmit radiation, and is provided between the radiation transmission window of the radiation generation apparatus 1 and the restricting blade 204. The radiation emitted from the radiation transmitting window of the radiation generating apparatus 1 is transmitted through the reflection mirror 201 and irradiated onto the subject 7 through the opening 203 of the limiting blade 204. The reflection mirror 201 has a reflection surface that reflects visible light from the visible light source 202 and is provided to be inclined with respect to the radiation axis 8.

  The radiation axis 8 refers to a straight line connecting the radiation focal point 9 of the radiation generator 1 and the center point when the opening 203 of the restricting blade 204 is widened to the maximum. The radiation focus 9 of the radiation generation apparatus 1 is a radiation generation point, and specifically refers to the center point of the electron irradiation region on the radiation generation target.

  The visible light source 202 faces the reflection surface of the reflection mirror 201 and is provided at a position symmetrical to the radiation focal point 9 with respect to this reflection surface. That is, the visible light source 202 is provided in a positional relationship conjugate with the radiation focus 9. Since the visible light source 202 and the reflection mirror 201 are provided in such a positional relationship, the visible light from the visible light source 202 is reflected by the reflection mirror 201 and then passes through the same path as the radiation. The subject 7 is irradiated to form a visible light irradiation field. The visible light source 202 is not particularly limited as long as it emits visible light having a necessary brightness, but a light emitting diode can be preferably used because it can be easily downsized.

  In addition, in the positional relationship of the optical conjugate, the configuration in which the center of the light emitting part of the visible light source 202 and the radiation focus 9 are symmetrical with respect to the reflection surface of the beam splitter 10 is a simulated display of the radiation field. This is a more preferable aspect in view of the accuracy.

  The restricting blade 204 forms an opening 203 that allows passage of radiation and visible light at the center. The restricting blade 204 is made of a metal such as lead, tungsten, molybdenum, or a radiation shielding material containing them so that unnecessary radiation can be shielded and a radiation field having a required size can be defined. Visible light is also limited. The radiation emitted from the radiation generator 1 is irradiated to the subject 7 through the opening 203 within a predetermined radiation irradiation field. In addition, visible light from the visible light source 202 is also reflected by the reflection mirror 201 and then irradiated to the subject 7 from the opening 203 within a predetermined visible light irradiation field. The size of the opening 203 of the restriction blade 204 can be adjusted. By adjusting the size of the opening 203, the size of the radiation field and the size of the corresponding visible light field can be adjusted. It is like that. For example, the limiting blade 204 may be formed by stacking two plate materials having notches or holes so that the notches or holes overlap each other so as to be slidable with each other. In this case, the opening 203 is formed as a notch or an overlapped portion of the holes, and the size of the opening 203 can be adjusted by sliding the two plate members relative to each other. Further, a plurality of plate materials can be used so as to be surrounded by these plate materials so as to form the opening 203 so that the positions can be shifted and slidably overlapped, or a camera shutter-like structure can be used.

  The camera 3 is provided at a position where the subject 7 can be directly imaged without passing through the opening 203 of the restriction blade 204. That is, unlike the radiation imaging system described in the background art, it is not provided at the position of the visible light source 202 instead. Therefore, the imaging of the subject 7 by the camera 3 and the visible light by the visible light source 202 are performed. The formation of the irradiation field can be performed simultaneously. The camera 3 can directly photograph the subject 7 in which a visible light irradiation field is formed from outside the visible light irradiation path, and this captured image is displayed on the display unit 4 in real time. Although the illustrated camera 3 is provided adjacent to the movable diaphragm 2, the camera 3 may be built in the movable diaphragm 2.

  The camera 3 preferably includes a measurement unit 301 that can measure the distance to the subject. As the measurement unit 301, an autofocus function can be used. When the measuring unit 301 is included, the distance from the subject 7 is measured by the measuring unit 301, and the camera 3 captures an image from a position different from the position of the visible light source 202 (the position of the radiation focus 9) based on this distance. It is possible to correct image distortion caused by the image. That is, the measurement unit 301 measures the distance from the image sensor of the camera 3 to the surface of the subject 7, and determines the radiation from the measured distance and the positional relationship between the radiation focus 9 and the image sensor that are known in advance. The distance from the focal point 9 to the surface of the subject 7 can be calculated. Then, based on the distance between the radiation focus 9 and the surface of the subject 7 and the positional relationship between the radiation focus 9 and the imaging element, which are known in advance, an image due to a mismatch between the imaging position and the position of the visible light source 202 is obtained. Can be corrected. By having such a correction function, it is possible to more accurately set the radiation field on the screen of the display unit 3 described later.

  The display unit 4 displays an image of the subject 7 including the visible light irradiation field photographed by the camera 3. For example, a liquid crystal display, a plasma display, or the like can be used. The display unit 4 not only displays the image on the screen but also has a setting function that can set the radiation field on the screen based on the displayed visible light field and the image of the subject 7. preferable. Specifically, for example, a touch panel type screen can include a function that can specify the range of the radiation irradiation field with a touch pen, and a function that can specify the range of the radiation irradiation field with a drag using a mouse. Also, a function that can specify the range of the radiation field as an area connecting the points clicked by the mouse, a function that can specify the range of the radiation field by inputting coordinates set on the screen, and the like. The radiation field data set on the screen of the display unit 4 in this way is sent to the system control unit 6, and the system control unit 6 sets the size of the radiation field set by the size of the opening 203 of the restriction blade 204. It will be adjusted accordingly. The display unit 4 also has functions such as ON / OFF switching of the camera 3, ON / OFF switching of the visible light source 202, light amount adjustment, setting of radiation generation conditions, ON / OFF switching of radiation irradiation, and the like. Is preferred. By having these functions, it is possible to efficiently perform operations necessary for photographing at one place.

  In FIG. 2, 401 is a screen, 402 is an ON / OFF switch for the camera 3, 403 is an ON / OFF switch for the visible light source 202, and 404 is a light amount adjustment button for the visible light source 202. 405 is a radiation generation condition setting button, 406 is a radiation irradiation ON / OFF switch, 407 is a radiation field setting switch, and 408 is a visible light field (radiation field) displayed on the screen.

  The radiation detection apparatus 5 includes a detector 501 that detects radiation transmitted through the subject 7 and converts the detected radiation into an image signal. The signal processing unit 502 receives an image signal from the detector 501, performs predetermined signal processing on the image signal under the control of the system control device 6, and outputs the processed image signal to the system control device 6. It has.

  The system control device 6 controls the radiation generation device 1 and the radiation detection device 5 in a coordinated manner. The drive circuit 102 of the radiation generation apparatus 1 outputs various control signals to the radiation generation tube 101 under the control of the system control apparatus 6. The emission state of the radiation emitted from the radiation generator 1 is controlled by this control signal. The radiation emitted from the radiation generator 1 is partially shielded by the restricting blades 204 of the movable diaphragm 2, irradiated to the subject 7 as a predetermined radiation irradiation field, transmitted through the subject 7 and detected by the detector 501. Is done. The detector 501 converts the detected radiation into an image signal and outputs the image signal to the signal processing unit 502. The signal processing unit 502 performs predetermined signal processing on the image signal under the control of the system control device 6, and outputs the processed image signal to the system control device 6. The system control device 6 outputs a display signal for displaying an image on the display unit 4 based on the processed image signal. The display unit 4 displays an image based on the display signal on the screen as a captured image of the subject 7. In addition, some or all of the functions of the system control device 6, the display unit 4, and the signal processing unit 502 may be integrated into a server, a workstation, a personal computer (PC), or the like (not shown). .

  Next, an operation flow of the radiation imaging system according to the first example of the present invention will be described.

  As shown in FIG. 3, the camera 3 is operated to start the radiographic flow. When the camera 3 is operated, an image of the subject 7 photographed by the camera 3 is displayed on the display unit 4 in real time. Usually, the imaging with the camera 3 and the image display on the display unit 4 are continued until the radiation imaging is completed.

  While the photographing by the camera 3 is started, the visible light source 202 is turned on, and the visible light irradiation flow shown in FIG. 3 is started. When the visible light source 202 is turned on, an image of the subject 7 including the visible light irradiation field formed on the subject 7 is displayed on the display unit 4. The visible light irradiation field at this stage is a temporary visible light irradiation field. Normally, the shape of the opening 203 of the restricting blade 204 is a square, so that the visible light irradiation field (radiation irradiation field) is also displayed in a square. The timing for starting the visible light irradiation flow may be before, after, or simultaneously with the start of the radiation imaging flow.

  When the display unit 4 has the above-described radiation field setting function on the screen, a desired radiation field is set on the screen based on the image of the subject 7 including the visible light field. This setting data is sent to the system control device 6, the limit blade 204 of the movable diaphragm 2 is driven via the system control device 6, and the size of the opening 203 is adjusted according to the set size of the radiation irradiation field. The This adjustment can be confirmed as a change in the size of the visible light irradiation field. And since the image containing the determined visible light irradiation field is displayed on the display part 4, the set radiation irradiation field can be confirmed.

  When the display unit 4 does not have the above-described setting function of the radiation field on the screen, the limit blade 204 of the movable diaphragm 2 is driven while viewing the image of the subject 7 including the visible light field, thereby opening the aperture. The size of 203 is adjusted to a desired visible light irradiation field size.

  Since the visible light irradiation field is formed by the visible light source 202 provided at a position symmetrical to the radiation focal point 9 with respect to the reflection surface of the reflection mirror 201, the visible light irradiation field substantially coincides with the radiation irradiation field. Further, the visible light irradiation field can be visually confirmed together with the subject 7 directly or as an image of the display unit 4. In particular, when the subject 7 is a person, depending on the imaging region and the orientation of the subject 7, the subject 7 can also confirm the radiation irradiation field as the visible light irradiation field.

  As described above, the image of the subject 7 and the visible light field captured by the camera 3 is displayed on the screen of the display unit 4 in real time. Therefore, when the visible light irradiation field is shifted due to the movement of the subject 7 after determining the visible light irradiation field (radiation irradiation field), it can be confirmed on the display unit 203 and the radiation irradiation field can be reset. Easily possible.

  The visible light source 202 is preferably switched on and off and the amount of light is adjusted so that it can be operated at an arbitrary timing independently of the radiation imaging flow, for example, the amount of light is changed according to changes in sunlight. . As described above, it is preferable that the visible light source 202 can be switched on and off and the amount of light can be adjusted on the display unit 4. However, the movable diaphragm 2 can be provided with these switches. May be.

  After the radiation irradiation field is determined as described above, radiation is generated and irradiated under predetermined radiation generation conditions. The radiation generation conditions include the voltage and current supplied to the radiation generation tube 101, the driving time of the radiation generation tube 101, the diameter of the electron beam applied to the radiation generation target, and the like. The radiation generated in the radiation generation tube 102 and emitted from the radiation generation apparatus 1 is restricted so as to hit only the radiation field set by the restriction blade 204, passes through the subject 7, and is detected by the detector 501. Then, an image is created from the detected radiation and displayed on the display unit 4.

  As long as the camera 3 can transmit arbitrary captured image information to the display unit 4 at a predetermined control timing, various imaging devices can be arbitrarily applied, but a video camera that continues to send real-time images is suitable. Optical information (carrier wave, wavelength) constituting an image acquired by the camera 3 can be optical information including not only a visible light component but also a visible light component and a wavelength component outside the visible light component as an auxiliary spectrum. .

  By using the radiation irradiation system of the present invention, it is possible to easily set the radiation field while observing the state of the subject 7 in a wide range, and the subject 7 can be confirmed immediately before the radiation irradiation. Unnecessary exposure can be prevented even if the specimen 7 moves suddenly. In addition, it is possible to set a radiation field from outside the radiographing room, and the inspection time can be shortened. Furthermore, since the radiation irradiation field can be visually confirmed by the visible light irradiation field, the actual radiation irradiation field can be correctly confirmed three-dimensionally even when the subject 7 is a person with a large body thickness. Become.

  Next, a radiation imaging system according to another example of the present invention will be described with reference to FIG.

  Each example shown in FIG. 4 is basically the same as the first example described with reference to FIG. 1 except that the beam splitter 10 is added and the installation position of the camera 3 is different. Although not shown in FIG. 4, each example of FIG. 4 includes the display unit 4, the signal processing unit 502, and the system control device 6.

  In the radiation imaging system according to the second example of the present invention shown in FIG. 4A, the beam splitter 10 is provided between the limiting blade 204 and the subject 7. The beam splitter 10 can transmit radiation, and has transparency and reflectivity to visible light. The beam splitter 10 may have different transmittance and reflectance with respect to visible light. However, in order to enable the camera 3 to capture the visible light irradiation field clearly, a half mirror in which both are equal is preferable.

  The beam splitter 10 is provided to be inclined with respect to the radiation axis 8. The camera 3 is provided between the limiting blade 204 and the subject 7 or the detector 501 so as to face the reflecting surface of the beam splitter. The beam splitter 10 and the camera 3 are provided in a positional relationship in which the imaging device of the camera 3 is symmetric with the radiation focal point 9 of the radiation generating device 1 with respect to the reflection surface of the beam splitter 10, that is, an optical conjugate positional relationship. ing. In addition, a reflection mirror 201 capable of transmitting radiation is provided between the radiation generator 1 and the restriction blade 204. The visible light source 202 is provided at a position symmetrical to the radiation focus 9 of the radiation generating apparatus 1 with respect to the reflection surface of the reflection mirror 201, that is, at an optically conjugate position, as in the first example. .

  In the optical conjugate positional relationship, it is preferable that the center of the imaging element of the camera 3 and the radiation focus 9 are symmetrical with respect to the reflecting surface of the beam splitter 10. Such a configuration is a more preferable aspect in view of consistency between the radiation field simulated by the visible light source 202 and the radiation field captured by the camera 3.

  In the radiation imaging system according to the third example of the present invention shown in FIG. 4B, the tilt of the beam splitter 10 is opposite to that of the second example, and the camera 3 is bounded by the radiation axis 8. It is provided at a position opposite to the visible light source 202. Except for these points, the second example is the same as the second example of FIG.

  The radiation imaging system according to the fourth example of the present invention shown in FIG. 4C has a configuration in which the beam splitter 10 and the camera 3 are built in a common housing. Moreover, it is preferable that the housing | casing of the movable aperture diaphragm 2 is an optical housing | casing, and what is possible with the inner surface and the member to incorporate is black which absorbs visible light. Except for these points, the second example is the same as the second example of FIG. This makes it easier to protect the beam splitter 10 and the camera 3. Note that the beam splitter 10 and the camera 3 according to the third example of FIG. 4B may be configured to be built in a casing common to the movable diaphragm 2.

  With the configuration shown in FIG. 4 as described above, the visible light source 202 and the radiation focus 9 and the imaging device of the camera 3 and the radiation focus are in a conjugate positional relationship. Images can be taken. Therefore, it is possible to set the radiation field accurately without adding an image correction function, and thus the system configuration can be simplified.

  In the radiation imaging system of the present invention, when setting a radiation field from an image displayed on the display unit 4, a provisional radiation field can be automatically set by selecting a region to be imaged. . In addition, when the condition of the subject 7 and the imaging region are selected, pre-registered radiation irradiation conditions (voltage, current, time, focal diameter, etc.) can be automatically set.

  For example, feature extraction is performed using an image captured by a camera, and the shape pattern of the subject 7 is digitized. Next, referring to a table composed of reference shape patterns of a plurality of subjects 7 stored in advance in a storage device (not shown), conformity determination is performed, and from the digitized shape pattern of the subject 7, the subject 7 to be imaged. Next, with reference to a table stored in a storage device (not shown) configured from a plurality of predetermined imaging range menus and imaging targets of the plurality of subjects 7, Propose and display radiation fields. The automatically proposed provisional radiation field can be confirmed using the visible light field and corrected if necessary. By adopting such an automatic proposal, the inspection time can be further shortened. In specifying the imaging target region of the subject 7, items such as the orientation and physique of the subject 7 may be selected to improve the pattern matching accuracy between the reference shape pattern and the imaging target region.

  DESCRIPTION OF SYMBOLS 1 Radiation generator, 2: Movable aperture, 3: Camera, 4: Display part, 5: Radiation detection apparatus, 6: System control apparatus, 7: Subject, 8: Radiation axis, 9: Radiation focus, 10: Beam splitter , 101: radiation generating tube, 102: driving circuit, 201: reflecting mirror, 202: visible light source, 203: aperture, 204: restricting blade, 301: measuring unit, 501: detector, 502: signal processing unit

Claims (10)

By forming an opening through which the radiation from the radiation generator passes, and by irradiating visible light through the opening of the limiting blade, the limiting blade defining the radiation irradiation field to the subject according to the size of the opening In a radiation imaging system comprising a visible light source that simulates and displays the radiation field as a visible light field,
A camera for photographing the subject and a display unit for displaying an image photographed by the camera, and capable of simultaneously performing photographing of the subject by the camera and formation of the visible light irradiation field by the visible light source Radiation imaging system characterized by being. By forming an opening through which the radiation from the radiation generator passes, and by irradiating visible light through the opening of the limiting blade, the limiting blade defining the radiation irradiation field to the subject according to the size of the opening In a radiation imaging system comprising a visible light source that simulates and displays the radiation field as a visible light field,
A camera for photographing the subject; and a display unit for displaying an image photographed by the camera, wherein the camera is provided at a position where the subject can be photographed without passing through the opening of the restriction blade. A radiation imaging system characterized by that.   A reflection mirror capable of transmitting radiation is provided between the radiation generation device and the restriction blade, and the visible light source is symmetrical to the radiation focus of the radiation generation device with respect to the reflection surface of the reflection mirror. A beam splitter that is capable of transmitting radiation across the radiation path between the limiting blade and the subject, and the camera reflects the beam splitter. The radiation imaging system according to claim 1, wherein the radiation imaging system is provided at a position symmetrical to the radiation focus with respect to a plane.   5. The radiation imaging system according to claim 4, wherein the camera is provided such that a center of an imaging element is symmetrical with respect to the radiation focus with respect to a reflection surface of the beam splitter.   The radiation imaging system according to claim 3 or 4, wherein the reflection mirror, the visible light source, the limiting blade, the beam splitter, and a camera are built in a common housing.   The radiation imaging system according to claim 1, wherein the camera is provided at a position where the subject including the visible light irradiation field can be directly imaged from outside the visible light irradiation path. .   The image display device includes a distortion correction function that corrects distortion caused by the image of the visible light irradiation field displayed on the display unit being captured from a position different from the position of the visible light source. The radiation imaging system according to claim 6.   2. The system according to claim 1, further comprising: a system control unit that can set the radiation field on the screen of the display unit and adjusts the size of the opening of the restriction blade based on the set radiation field. The radiography system as described in any one of thru | or 7.   In the display unit, the ON / OFF switching of the camera, the ON / OFF switching of the visible light source, the light amount adjustment of the visible light source, the setting of radiation generation conditions, and the ON / OFF switching of radiation irradiation. The radiographic system according to claim 1, wherein one or more can be performed.   The radiation imaging system according to claim 1, wherein the radiation imaging system has a function of automatically setting a radiation irradiation field by selecting a part of the subject to be imaged.

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