Patent Publication Number: US-2021161501-A1

Title: Radiography apparatus

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
     This application is a Continuation of PCT International Application No. PCT/JP2019/032167 filed on 16 Aug. 2019, which claims priority under 35 U.S.C. § 119(a) to Japanese Patent Application No. 2018-153576 filed on 17 Aug. 2018. The above application is hereby expressly incorporated by reference, in its entirety, into the present application. 
    
    
     BACKGROUND OF THE INVENTION 
     1. Field of the Invention 
     The present invention relates to a radiography apparatus that images a subject using radiation, such as X-rays. 
     2. Description of the Related Art 
     A radiography apparatus comprises a radiation source that generates radiation, and a radiation detection unit that detects radiation. A subject is disposed between the radiation source and the radiation detection unit. Then, the radiography apparatus acquires an image of the subject (in particular, the inside of the subject) by detecting radiation transmitted through the subject with the radiation detection unit. 
     In the radiography apparatus, the radiation source and the radiation detection unit may be movable independently. For example, in a mobile X-ray imaging apparatus (so-called treatment cart), a radiation source and a radiation detection unit are movable independently. In a case where the radiation source and the radiation detection unit are movable independently, alignment of the radiation source and the radiation detection unit is required at the time of imaging. In recent years, a radiography apparatus that detects a position of a radiation detection unit and moves a radiation source in conformity with the position of the radiation detection unit is known (JP2015-156896A and JP1999-276463A (JP-H11-276463A)). 
     SUMMARY OF THE INVENTION 
     In a case where the radiation source and the radiation detection unit are movable independently, alignment of at least the radiation source and the radiation detection unit is required. Meanwhile, merely aligning relative positions of the radiation source and the radiation detection unit may cause failure in imaging. This is because a subject can be discretionarily disposed between the radiation source and the radiation detection unit. Specifically, in a case where the subject is not in a detection effective region of the radiation detection unit, even though the radiation source and the radiation detection unit are aligned, there is a problem in that the whole of the subject is not captured in an acquired radiographic image. For this reason, it is desirable that a radiography apparatus, in which a radiation source and a radiation detection unit are movable independently, supports imaging in consideration of disposition of a subject. 
     An object of the invention is to provide a radiography apparatus that supports reliable imaging even though a radiation source and a radiation detection unit are movable independently. 
     A radiography apparatus according to an aspect of the invention comprises a radiation source that generates radiation, a radiation detection unit that is movable independently with respect to the radiation source and obtains an image of a subject by detecting the radiation transmitted through the subject, an imaging unit that images at least the subject using light having a wavelength longer than the radiation, a first recognition unit that recognizes the radiation detection unit, a second recognition unit that recognizes the subject using an image captured by the imaging unit, a determination unit that, using recognition results of the first recognition unit and the second recognition unit, specifies a relative positional relationship between the radiation detection unit and the subject and determines whether or not the subject is in a detection effective region of the radiation detection unit, and a controller that performs operation support using a determination result of the determination unit. 
     It is preferable that the controller notifies that the subject is in the detection effective region or that the subject is not in the detection effective region. 
     It is preferable that, in a case where the subject is not in the detection effective region, the controller notifies that the subject is not in the detection effective region after the second recognition unit recognizes the subject. 
     In a case where the subject is not in the detection effective region and the subject is not recognizable by the second recognition unit, the controller notifies that the subject is not recognizable. 
     It is preferable that the controller validates or invalidates exposure of the radiation using the determination result. 
     It is preferable that the controller validates the exposure of the radiation in a case where the subject is in the detection effective region. 
     It is preferable that the controller invalidates the exposure of the radiation in a case where the subject is not in the detection effective region. 
     It is preferable that the controller performs operation support of position adjustment for putting the subject in the detection effective region in a case where the subject is not in the detection effective region. 
     It is preferable that the controller notifies of a direction for moving the radiation detection unit to put the subject in the detection effective region. 
     It is preferable that the controller notifies of a distance for moving the radiation detection unit to put the subject in the detection effective region. 
     It is preferable that the controller notifies of an orientation, a direction, or an angle for rotating or inclining the radiation detection unit to put the subject in the detection effective region. 
     It is preferable that the radiography apparatus further comprises a collimator that defines an irradiation field of the radiation, and the controller performs control using the determination result that the collimator adjusts the irradiation field. 
     It is preferable that the radiography apparatus further comprises a collimator that defines an irradiation field of the radiation, and the controller puts the subject in the detection effective region by performing control using the determination result such that the collimator changes the irradiation field. 
     It is preferable that the radiography apparatus further comprises a collimator that defines an irradiation field of the radiation, and the controller performs control such that the collimator changes the irradiation field in conformity with the subject in a case where the subject is in the detection effective region. 
     It is preferable that the first recognition unit specifies a position and an orientation of the radiation detection unit. 
     It is preferable that the first recognition unit recognizes the radiation detection unit using the image acquired by the imaging unit. 
     It is preferable that the radiation detection unit has a marker indicating a position, and the first recognition unit recognizes a position and an orientation of the radiation detection unit using the marker in the image acquired by the imaging unit. 
     It is preferable that the radiation detection unit comprises a position sensor that measures a position of the radiation detection unit, and the first recognition unit recognizes the radiation detection unit using information obtained with the position sensor. 
     It is preferable that the second recognition unit recognizes a part of the subject. 
     It is preferable that the second recognition unit recognizes the part of the subject by matching of an image of the subject captured by the imaging unit and a template. 
     It is preferable that the second recognition unit is artificial intelligence. 
     It is preferable that the controller automatically moves the radiation source to a position confronting the radiation detection unit in a case where the first recognition unit recognizes the radiation detection unit. 
     It is preferable that the controller automatically moves the radiation source in a case where the radiation detection unit is horizontal and stationary. 
     It is preferable that, in a case of automatically moving the radiation source, the controller notifies of an effect that the radiation source is to be moved. 
     It is preferable that the controller maintains a distance between the radiation source and the radiation detection unit at a specific distance. 
     It is preferable that the controller moves the imaging unit in a case where the second recognition unit does not recognize the subject. 
     It is preferable that the radiography apparatus further comprises a body thickness measurement unit that measures a body thickness of the subject, and the controller performs operation support using the determination result and the body thickness of the subject. 
     It is preferable that the controller sets an imaging condition using the body thickness of the subject in a case where the subject is in the detection effective region. 
     It is preferable that the controller sets a tube voltage of the radiation source using the body thickness of the subject. 
     It is preferable that the controller inserts or extracts a filter shielding a part of the radiation between the radiation source and the subject using the body thickness of the subject. 
     It is preferable that, in a case of manually moving the radiation source, the controller notifies that the radiation source is at a position confronting the radiation detection unit. 
     It is preferable that, in a case of manually moving the radiation source, the controller notifies of a direction for moving the radiation source. 
     It is preferable that, in a case where the radiation detection unit is attached to a main body including the controller, the controller restricts movement of the radiation source. 
     It is preferable that, in a case where the radiography apparatus is a mobile type and a main body including the controller is moving, the controller restricts movement of the radiation source. 
     According to the aspect of the invention, it is possible to provide a radiography apparatus that supports reliable imaging even though a radiation source and a radiation detection unit are movable independently. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  is a perspective view of a radiography apparatus. 
         FIG. 2  is a perspective view of the radiography apparatus. 
         FIG. 3  is a perspective view of the radiography apparatus in which an arm portion is folded. 
         FIG. 4  is a plan view showing the configuration of a distal end portion. 
         FIG. 5  is an explanatory view of markers that are provided on a surface of a radiation detection unit. 
         FIG. 6  is a block diagram of the radiography apparatus. 
         FIG. 7  is an explanatory view of template matching that is performed by a second recognition unit. 
         FIG. 8  is a block diagram of a controller. 
         FIG. 9  is a flowchart showing an operation aspect of the radiography apparatus. 
         FIG. 10  is an explanatory view showing disposition at the time of imaging. 
         FIG. 11  is an explanatory view showing disposition of the radiation detection unit and a subject on a bed. 
         FIG. 12  is a display example of a touch panel. 
         FIG. 13  is a block diagram of a radiography apparatus of a second embodiment. 
         FIG. 14  is a flowchart showing an operation aspect of the radiography apparatus of the second embodiment. 
         FIG. 15  is a display example showing an aspect of supporting re-disposition of a radiation source. 
         FIG. 16  is a display example showing an aspect of supporting re-disposition of the radiation source. 
         FIG. 17  is a perspective view of a radiography apparatus having a telescopic arm. 
     
    
    
     DESCRIPTION OF THE PREFERRED EMBODIMENTS 
     First Embodiment 
     As shown in  FIGS. 1 and 2 , a radiography apparatus  10  comprises a main body  11 , an arm portion  12 , a distal end portion  13 , and a radiation detection unit  15 . 
     The main body  11  incorporates a control substrate or the like that controls each portion of the radiography apparatus  10 , such as the arm portion  12  and the distal end portion  13 . The radiography apparatus  10  is a mobile type (so-called treatment cart), and casters  21  are attached to the main body  11 . For this reason, it is possible to not only perform radiography not only in a specific laboratory but also move the radiography apparatus  10  to a patient&#39;s room where a patient  101  (see  FIG. 10 ) as a subject is present and perform radiography in the patient&#39;s room. The casters  21  are rotatable manually or automatically according to settings or the like (selection of an operation mode, and the like). That is, a laboratory technician, a physician, other medical staff, or the like (hereinafter, referred to as a laboratory technician or the like) can manually move the radiography apparatus  10  by pushing and pulling the radiography apparatus  10 . Furthermore, the radiography apparatus  10  can automatically move or adjust a position of the apparatus (main body  11 ). The main body  11  is provided with a grip portion  22  that is gripped by the laboratory technician or the like in manually moving the radiography apparatus  10 . 
     The main body  11  comprises a touch panel  23 . The touch panel  23  is a display unit of the radiography apparatus  10  and is an operating unit. The touch panel  23  displays an image of a subject obtained by radiography, items pertaining to operations and settings, and the like. In regard to the items pertaining to the operations and the settings, the laboratory technician or the like can perform an input of settings, an input of an operation instruction, and the like to the radiography apparatus  10  by touching the touch panel  23  with a finger or the like. 
     In addition, the main body  11  has an insertion type holder  24  in which the radiation detection unit  15  is put. Inside the holder  24 , a sensing unit (not shown) that senses insertion or non-insertion of the radiation detection unit  15  is provided. For this reason, the radiography apparatus  10  can sense insertion and extraction of the radiation detection unit  15 . The sensing unit is, for example, a switch that is turned on in a case where the radiation detection unit  15  is held in the holder  24  and is turned off in a case where the radiation detection unit  15  is extracted from the holder  24 . 
     The arm portion  12  holds the distal end portion  13  with respect to the main body  11 . The arm portion  12  is foldable. In a case where the radiography apparatus  10  is moved to a patient&#39;s room or the like, the arm portion  12  is folded as shown in  FIG. 3 , and in a case where imaging is performed, the arm portion  12  is expanded (see  FIG. 1  or the like). The radiography apparatus  10  can dispose the position of the distal end portion  13  at a position (hereinafter, referred to as an imaging position) for use in imaging by adjusting an expansion angle of the arm portion  12 . The arm portion  12  has a lock mechanism (not shown) and can maintain any expansion angle. For this reason, in a case where imaging is performed, the arm portion  12  can maintain the position of the distal end portion  13  at the imaging position. Folding and expanding of the arm portion  12  can be performed manually or automatically according to settings. 
     The distal end portion  13  is attached to a distal end of the arm portion  12  to be rotationally movable with respect to the arm portion  12 , and incorporates a radiation source  31  (see  FIG. 6 ) that generates radiation. The distal end portion  13  has a collimator  32  that defines an irradiation field  105  (see  FIG. 10 ) of radiation, and one or a plurality of handles  33 . 
     The radiation source  31  is an X-ray tube in the embodiment. For this reason, the radiography apparatus  10  is an X-ray imaging apparatus that images a subject using X-rays. Energy, a dose, or the like of radiation generated by the radiation source  31  is one of imaging conditions in radiography and can be set manually or automatically. In the embodiment, the energy of the exposure X-rays can be changed by adjusting a tube voltage of the X-ray tube. The dose of the exposure X-rays can be changed by adjusting a tube current of the X-ray tube. As the radiation source  31 , a radiation source that generates radiation (gamma-rays or the like) other than X-rays can be used. 
     The collimator  32  incorporates one or a plurality of shielding plates (not shown) that shield radiation generated by the radiation source  31 , and adjusts the size and shape of the irradiation field of exposure radiation by adjusting at least one of a position or an orientations (angle) of each shielding plate. For example, the collimator  32  has four shielding plates. The collimator  32  forms the shape of exposure radiation in a rectangular shape and adjusts the size of the rectangular shape with the four shielding plates. The adjustment of the irradiation field  105  using the collimator  32  can be performed manually or automatically according to settings. The irradiation field  105  of radiation is one of imaging conditions in radiography. 
     The handle  33  is gripped, for example, in a case where the laboratory technician or the like manually moves the distal end portion  13 , or the like. The handle  33  also functions as a guard that maintains a minimum distance distal end portion  13  and the subject in a case where the distal end portion  13  is disposed close to the subject. 
     In addition, as shown in  FIG. 4 , the distal end portion  13  has an imaging unit  35 . The imaging unit  35  images at least the subject using light having a wavelength longer than radiation generated by the radiation source  31 . Light having a wavelength longer than radiation generated by the radiation source  31  is, for example, ultraviolet rays, visible light, infrared rays, or the like. Accordingly, the imaging unit  35  is a camera that images the subject or the like using electromagnetic waves or the like other than radiation. More specifically, the imaging unit  35  is, for example, a digital camera, a video camera, or the like. 
     An imaging range of the imaging unit  35  includes at least an exposure range of radiation generated by the radiation source  31 . This is because an image (hereinafter, referred to as a camera image  121 ; see  FIG. 10 ) captured by the imaging unit  35  is used in recognition processing of recognizing the subject or the like, and as a result, is used to determining whether or not the subject is in a detection effective region of the radiation detection unit. 
     The subject that is at least used by the imaging unit  35  as an imaging target is a subject, such as a patient, to be imaged by the radiography apparatus  10  using radiation. The imaging unit  35  may use the radiation detection unit  15  as an imaging target. This is because the radiography apparatus  10  may use an image obtained with the imaging unit  35  in recognition processing of recognizing the radiation detection unit  15 . 
     The radiation detection unit  15  is movable independently with respect to the radiation source  31  and obtains an image (hereinafter, referred to as a radiographic image) of the subject by detecting radiation transmitted through the subject. Obtaining the radiographic image with the radiation detection unit  15  is referred to as radiography. In the embodiment, a so-called flat panel detector (FPD) is applied. As shown in  FIG. 5 , in the radiation detection unit  15 , markers indicating positions, such as at least one of a marker  41  indicating the position of the center of the detection effective region, a marker  42  indicating a position and a range of the detection effective region, or markers  43 A to  43 D indicating positions of corner portions of the radiation detection unit  15 , are appropriately provided. This is to allow at least one of the laboratory technician, the radiography apparatus  10 , or the like to easily recognize a position and an orientation of the radiation detection unit  15 , the detection effective region, and the like. The detection effective region is a region where there are pixels contributing to a radiographic image and detection of radiation is actually effective. The markers  43 A to  43 D can be identified in distinction from one another using a shape, a color, or the like. In the embodiment, the markers  43 A to  43 D are an L shape, and the markers  43 A to  43 D are different in length of a side of the L shape for identification. 
     As shown in  FIG. 6 , the distal end portion  13  comprises a filter  36  in addition to the radiation source  31 , the collimator  32 , and the imaging unit  35 . The filter  36  is a member that shields a part of radiation generated by the radiation source  31 , and is insertable and extractable into and from an exposure path of radiation generated by the radiation source  31 . The filter  36  is, for example, a thin plate made of copper or the like, and in the embodiment, primarily shields a low energy component out of radiation generated by the radiation source  31 . For this reason, in a case where the filter  36  is inserted into the exposure path of radiation, compared to a case where the filter  36  is not used, the low energy component of radiation decreases, and radiation containing a relatively large amount of high energy component reaches the subject and the radiation detection unit  15 . 
     The radiation detection unit  15  comprises a battery  49  or the like that supplies electric power to an image acquisition unit  46 , a communication unit  47 , a position sensor  48 , and each unit of the radiation detection unit  15 . 
     The image acquisition unit  46  receives radiation to acquire a radiographic image. In a case where the radiation detection unit  15  is a so-called indirect conversion type, the image acquisition unit  46  includes a scintillator that converts radiation into an optical signal once, and then, converts the optical signal into an electrical signal, such as gadolinium oxide sulfur (GOS) or cesium iodide (CsI), thin film transistor (TFTs), and the like. In a case where the radiation detection unit  15  is a so-called direct conversion type, the image acquisition unit  46  includes amorphous selenium or the like that directly converts radiation into an electrical signal, TFTs, and the like. 
     The communication unit  47  performs communication with the main body  11  in a wired or wireless manner and transmits and receives various control signals and the like. The communication unit  47  transmits the radiographic image acquired by the image acquisition unit  46  to the main body  11 . 
     The position sensor  48  is a sensor that detects the position and the orientation (including a direction of change or a change amount of the position or the orientation) of the radiation detection unit  15 . The position sensor  48  is, for example, a gyro sensor that detects an angular velocity or an angular acceleration, a speed sensor that detects a speed, an acceleration sensor that detects an acceleration, or a combination thereof. The position of the radiation detection unit  15  is a position with respect to the main body  11 , and is, for example, a position with respect to, in particular, a generation point  103  (so-called focus; see  FIG. 9 ) of radiation by the radiation source  31 . The orientation of the radiation detection unit  15  is a spatial rotation angle and an inclination angle of the radiation detection unit  15 . In the embodiment, the main body  11  traces the radiation detection unit  15  by recognizing the position and the orientation of the radiation detection unit  15  using information (for example, a signal output directly from the position sensor  48 ) obtained with the position sensor  48 . Note that the position sensor  48  can include a measurement unit that measures the position and the orientation of the radiation detection unit  15  using signals output directly from various sensors. In this case, the position sensor  48  can directly output information regarding the position and the orientation of the radiation detection unit  15 . 
     The main body  11  comprises a recognition unit  51 , a determination unit  52 , a controller  53 , a communication unit  54  that performs communication with the communication unit  47  of the radiation detection unit  15 , a storage unit  56  stores the radiographic image and the like acquired from the radiation detection unit  15 , and a battery  57  that supplies electric power to each unit of the main body  11  and the like. 
     The recognition unit  51  recognizes a part or the whole of at least one of the subject or the radiography apparatus  10 . The recognition that is performed by the recognition unit  51  refers to specification of a spatial position, an orientation, a size, a shape, and the like. In the embodiment, the recognition unit  51  comprises at least a first recognition unit  61  and a second recognition unit  62 . 
     The first recognition unit  61  recognizes the radiation detection unit  15 . The recognition of the radiation detection unit  15  refers to specification of (calculating or the like) a position and an orientation of the radiation detection unit  15  with respect to the main body  11 . In the embodiment, the first recognition unit  61  specifies a position and an orientation of the radiation detection unit  15  with the generation point  103  of radiation as a reference. The first recognition unit  61  recognizes the radiation detection unit  15  using at least one of the camera image  121  captured by the imaging unit  35  or an output signal or the like of the position sensor  48 . Since a position and an imaging range of the imaging unit  35  in the main body  11  are known, the first recognition unit  61  can recognize the radiation detection unit  15  using a position of at least one of an edge (side), an apex (angle), the marker  41 , the marker  42 , the markers  43 A to  43 D, or the like of the radiation detection unit  15  in the camera image  121 . The first recognition unit  61  can recognize the radiation detection unit  15  by specifying the position and the orientation of the radiation detection unit  15  using the output signal or the like of the position sensor  48 . In the embodiment, in principle, the first recognition unit  61  recognizes the radiation detection unit  15  by combining the camera image  121  and the output signal or the like of the position sensor  43 . Then, in a case where the radiation detection unit  15  is not captured in the camera image  121  to a degree enough for recognition, or the like, the first recognition unit  61  recognizes the radiation detection unit  15  using the output signal or the like of the position sensor  43 . 
     The recognition of the radiation detection unit  15  in the first recognition unit  61  includes recognition (specification of at least one of a position or an orientation) of the detection effective region of the radiation detection unit  15 . This is because the detection effective region is determined in advance for each radiation detection unit  15  and is known, and thus, the recognition of the radiation detection unit  15  is substantially synonymous with the recognition of the detection effective region of the radiation detection unit  15 . 
     The second recognition unit  62  recognizes the subject. The recognition of the subject refers to specification of at least one of a position, an orientation, a shape, a size, or the like of the subject. The recognition of the subject includes recognition of a part of the subject in addition to recognition of the whole subject. That is, the second recognition unit  62  can recognize a part of the subject. Specifically, the second recognition unit  62  can specify at least one of a position, an orientation, a shape, a size, or the like of a part (for example, a chest (portion) with respect to the patient (whole); hereinafter, referred to as an imaging part) for capturing a radiographic image in the subject. In the embodiment, the second recognition unit  62  specifies a position or the like of the subject with the generation point  103  of radiation as a reference. This is to uniformize the reference with the recognition of the radiation detection unit  15  in the first recognition unit  61 . 
     The second recognition unit  62  recognizes the subject using the camera image  121  captured by the imaging unit  35 . More specifically, the second recognition unit  62  recognizes the subject (in the embodiment, the imaging part) by matching (so-called template matching) of the camera image  121  of the subject captured by the imaging unit  35  and a template. The template is, for example, the camera image  121  in a case where a radiographic image without excess and deficiency is obtained on a specific imaging part. The second recognition unit  62  has a plurality of kinds of templates according to characteristics, such as at least one of age, sex, or physique of the subject, and recognizes the subject by matching using an appropriate template depending on to the characteristics of the subject or by round robin matching with the templates held therein. Matching refers to obtaining correlation with a template. The second recognition unit  62  specifies the position of the subject or the imaging part of the subject in the camera image  121  using the magnitude of the correlation with the template. As shown in  FIG. 7 , for example, the second recognition unit  62  compares a template  64 , in which a chest  64   a  of the patient is captured, with a part of the camera image  121  (the whole of the camera image  121  depending on the imaging range) to obtain correlation. Like a comparison range  65 A as a part of the camera image  121 , in a case where the subject significantly deviates from the subject captured in the template  64 , or the like, the correlation is small. On the other hand, like a comparison range  65 B, in a case where the position or the like of the subject substantially coincides with the template  64 , the correlation is large. For this reason, the second recognition unit  62  can specify that the subject (in particular, the chest as the imaging part) is present in the comparison range  65 B having large correlation or a portion in the vicinity. 
     The second recognition unit  62  changes a template to be used according to an imaging menu. Specifically, in a case where there is a setting of an imaging menu capable of specifying the imaging part, the second recognition unit  62  changes a template to be used according to the setting. The imaging menu is a setting pertaining to at least one of the subject or an imaging condition. For example, the second recognition unit  62  can appropriately use a template of a chest, a head, an abdomen, a limb, or the like. In a case where there is a setting of an imaging menu capable of specifying the characteristic of the subject, such as sex or age, the second recognition unit  62  changes a template to be used according to the setting. For example, the second recognition unit  62  appropriately uses a template for male and a template for female. For example, the second recognition unit  62  appropriately uses a template for aged person, a template for adult (for ordinary adult excluding aged person and child), or a template for child. In this way, the second recognition unit  62  can particularly accurately recognize the position or the like of the subject by appropriately using a plurality of kinds of templates according to the setting of the imaging menu. 
     In a case where an imaging menu is not used in template switching, such as a case where there is no imaging menu or a case where recognition processing of the second recognition unit  62  is not associated with the imaging menu, the second recognition unit  62  takes correlation using one or a plurality of representative templates among a plurality of templates held therein and decides a template to be used based on the template having the largest correlation. For example, in a case where the irradiation field  105  and the vicinity are captured in the camera image  121 , an imaging part can be specified by taking correlation with templates for adult of a chest, a head, an abdomen, and a limb. The same applies to the sex, age, or the like of the subject. In this case, the correlation with the representative templates is taken, whereby the second recognition unit  62  can finally properly select a template to be used. 
     The second recognition unit  62  can be constituted of artificial intelligence (AI) that has learned using an algorithm of machine learning or deep learning, such as a neural network (NN), a convolutional neural network (CNN), adaboost, or Random Forest, instead of the above-described template matching. In this case, training data (so-called OK image) of correct answer is, for example, the camera image  121  in a case where a radiographic image without excess and deficiency is obtained on a specific imaging part. Training data (so-called NG image) of incorrect answer is, for example, the camera image  121  in a case where a radiographic image with excess and deficiency is obtained. 
     Using recognition results of the first recognition unit  61  and the second recognition unit  62 , the determination unit  52  specifies a relative positional relationship between the radiation detection unit  15  and the subject and determines whether or not the subject is in the detection effective region of the radiation detection unit  15 . A determination reference regarding whether or not the subject is in the detection effective region of the radiation detection unit  15  is the generation point  103  of radiation and the irradiation field  105  of radiation. That is, “the subject is in the detection effective region of the radiation detection unit  15 ” refers to a positional relationship in which the imaging part of the subject is within the irradiation field  105  of radiation and radiation transmitted through the imaging part of the subject reaches the detection effective region. “The subject is not in the detection effective region of the radiation detection unit  15 ” refers to a positional relationship in which at least a part of the imaging part of the subject is out of the irradiation field  105  of radiation and at least a part of radiation transmitted through the imaging part of the subject does not reach the detection effective region. 
     in a case where the second recognition unit  62  recognizes the subject by template matching, the determination unit  52  can determine whether or not the subject is in the effective detection region of the radiation detection unit  15  based on information associated with a plurality of templates. In this case, determination regarding whether or not the subject is in the effective detection region of the radiation detection unit  15  can be accurately performed compared to a case where determination is performed based on information associated with one template. Information associated with a template is a classification of a part or the like of the subject represented by the template and a correlation value of the template and the camera image  121 . The correlation value of each template and the camera image  121  is calculated by the second recognition unit  62 . For example, in a case where the imaging part is a chest, a head is present in a predetermined direction with respect to the chest, and an abdomen is present in an opposite direction. For this reason, for example, the determination unit  52  can specify, as “chest”, a range where a correlation value with the template of the chest is equal to or greater than a first threshold value (a lower limit correlation value at which specification can be made to be the chest) and a correlation value with the template of the head is equal to or less than a second threshold value (an upper limit correlation value at which specification can be made to be not the head) and can determine whether or not the subject is in the detection effective region of the radiation detection unit  15 . In this case, a boundary between the head and the chest of the subject is accurate compared to a case where the range of “chest” is specified by the correlation value with the template of the chest. The same applies to a boundary between the chest and the abdomen, or the like. As described above, the second recognition unit  62  can recognize the subject based on information associated with a plurality of templates. In this case, the determination unit  52  can accurately determine whether or not the subject is in the effective detection region of the radiation detection unit  15  merely by using a recognition result of the second recognition unit  62 . 
     The controller  53  integrally controls the units of the radiography apparatus  10 . In particular, the controller  53  performs operation support of the radiography apparatus  10  using the determination result of the determination unit  52 . For example, as a result of the determination of the determination unit  52 , in a case where the subject is not in the detection effective region, the controller  53  performs operation support of position adjustment for putting the subject in the detection effective region. Specifically, as shown in  FIG. 8 , the controller  53  comprises an imaging controller  71 , a radiation controller  72 , a position controller  73 , and a notification unit  75 . 
     The imaging controller  71  controls the imaging unit  35 . For example, in a case where either of the first recognition unit  61  or the second recognition unit  62  requests the camera image  121 , the imaging controller  71  images the subject or the like with the imaging unit  35  and provides the camera image  121  to at least one of the first recognition unit  61  or the second recognition unit  62 . The imaging controller  71  moves the imaging unit  35  (in the embodiment, the distal end portion  13 ) in a case where the second recognition unit  62  does not recognize the subject. With this, in a case where the second recognition unit  62  does not recognize the subject, the controller  53  automatically searches the subject. 
     The radiation controller  72  controls the radiation source  31 , the collimator  32 , and the filter  36 . Specifically, the radiation controller  72  comprises a radiation source controller  81 , an irradiation field controller  82 , and a filter insertion-extraction controller  83 . 
     The radiation controller  72  controls the radiation source  31 , and performs a start or a stop of the radiation source  31 , settings of the energy, the dose, and the like of radiation generated by the radiation source  31  (in the embodiment, settings of the tube voltage and the tube current of the X-ray tube), a setting of validation or invalidation of exposure of radiation, control of an exposure timing of radiation, and the like. The control of the exposure timing is, for example, synchronization control or the like of exposure of the radiation from the radiation source  31  and the operation of the image acquisition unit  46 . Validation or invalidation of exposure of radiation refers to validating or invalidating an input of an exposure instruction from the laboratory technician or the like or validating or invalidating an input of a start instruction of the radiation source  31 . The radiation source controller  81  can validate or invalidate exposure of radiation using the determination result of the determination unit  52  according to the setting. With this, the controller  53  performs operation support of the radiography apparatus  10  (in particular, proper exposure control). For example, as a result of the determination of the determination unit  52 , in a case where the subject is in the detection effective region, the radiation controller  72  validates exposure of radiation. This is because a state in which radiography can be executed without failure is set. On the other hand, as a result of the determination of the determination unit  52 , in a case where the subject is not in the detection effective region, exposure of radiation is invalidated. This is because a state in which the subject cannot be radiographed without excess and deficiency is set, re-imaging is required, and an exposure dose of the subject increases. 
     The irradiation field controller  82  performs control such that the collimator  32  adjusts the irradiation field  105  of radiation. In principle, the irradiation field controller  82  makes the irradiation field  105  of radiation conform to the detection effective region of the radiation detection unit  15 . The irradiation field controller  82  can change the irradiation field  105  by performing control on the collimator  32  using the determination result of the determination unit  52  according to the settings. With this, the controller  53  performs operation support of the radiography apparatus  10  (in particular, the collimator  32 ). For example, as a result of the determination of the determination unit  52 , in a case where a part of the imaging part is out of the irradiation field  105  of an initial setting or the irradiation field  105  set by the laboratory technician or the like, the irradiation field controller  82  can put the subject (at least the imaging part) in the detection effective region by performing control such that the collimator  32  changes the irradiation field  105 . This is to obtain a radiographic image of the subject without excess and deficiency by single radiography. For example, as a result of the determination of the determination unit  52 , in a case where the subject is in the detection effective region, the irradiation field controller  82  performs control such that the collimator  32  changes the irradiation field in conformity with the subject according to a relationship between the subject and the size of the detection effective region. That is, in a case where the imaging part of the subject is smaller than the detection effective region, the irradiation field controller  82  narrows the irradiation field  105  in conformity with the imaging part of the subject. This is to reduce the exposure of the subject. 
     The filter insertion-extraction controller  83  controls insertion and extraction of the filter  36  into and from the exposure path of radiation. For example, in a case where the tube voltage set by the radiation source controller  81  is higher than a predetermined threshold value, the filter insertion-extraction controller  83  inserts the filter  36  into the exposure path of radiation. This is because, in a case where the tube voltage is set to be high, and radiation having high energy and high penetration is used for radiography, exposure to radiation having low energy and low penetration is reduced. 
     The position controller  73  controls the arm portion  12 , the distal end portion  13 , and the casters  21 . Specifically, the position controller  73  comprises a radiation source position controller  91  and a main body position controller  92 . 
     The radiation source position controller  91  controls the position of the radiation source  31  with respect to the radiation detection unit  15  by controlling folding and expanding of the arm portion  12  and the orientation of the distal end portion  13  with respect to the arm portion  12 . The radiation source position controller  91  can control the position of the radiation source  31  using at least one of the recognition result of the first recognition unit  61 , the recognition result of the second recognition unit  62 , the determination result of the determination unit  52 , or a combination thereof according to the settings. With this, the controller  53  performs operation support of the radiography apparatus  10  (in particular, the position of the radiation source  31 ). For example, the radiation source position controller  91  can automatically move the radiation source  31  to a position confronting the radiation detection unit  15  in a case where the first recognition unit  61  recognizes the radiation detection unit  15 . With this, it is possible to reduce an operation burden of the laboratory technician or the like pertaining to alignment of the radiation source  31  and the radiation detection unit  15 . The position confronting the radiation detection unit  15  refers to a position where radiation exposure can be performed to the detection effective region. 
     In a case of automatically moving the radiation source  31 , it is preferable that the radiation source position controller  91  automatically moves the radiation source  31  in a case where the radiation detection unit  15  is substantially horizontal and stationary. This is because the disposition of the radiation detection unit  15  is completed, and thus, the radiation source  31  can be moved safely without colliding with the laboratory technician or the like. In a case of automatically moving the radiation source  31 , it is preferable that the controller  53  notifies of an effect that the radiation source  31  is to be moved. This is to secure safety. The notification to the effect that the radiation source  31  is to be moved refers to a state in which the laboratory technician or the like can recognize the effect that the radiography apparatus  10  automatically moves the radiation source  31 . The notification to the effect that the radiation source  31  is to be moved is performed by the notification unit  75 . 
     The radiation source position controller  91  maintains a distance between the radiation source  31  and the radiation detection unit  15  at a specific distance. The distance between the radiation source  31  and the radiation detection unit  15  is a so-called source to image-receptor distance (SID). The specific distance is a distance appropriate for radiography according to at least one of the imaging part, the imaging conditions, or the like. 
     The main body position controller  92  adjusts the position and the orientation of the main body  11  in, for example, a patient&#39;s room or the like by controlling rotation of each caster  21 . In a case where the radiation source position controller  91  controls the position and the like of the radiation source  31 , the main body position controller  92  cooperates with the radiation source position controller  91  as necessary and adjusts the position and the orientation of the main body  11 . The main body position controller  92  can make the radiography apparatus  10  automatically or semiautomatically travel in a case of carrying the radiography apparatus  10  to the patient&#39;s room or the like. Semiautomatic traveling refers to assisting the movement of the radiography apparatus  10  by rotating the casters  21  in an orientation of reducing force pushing and pulling the radiography apparatus  10 . 
     The notification unit  75  notifies of information for supporting an operation of the radiography apparatus  10 . The notification refers to a state in which the laboratory technician or the like can recognize information. The notification unit  75  notifies of the above-described information, for example, by displaying a character, a message, a figure (icon or the like), a symbol, or the like on a screen of the touch panel  23 , generating sound or voice with a speaker (not shown), turning on or off an indicator (not shown), such as a lamp, or changing the display lamps. In the embodiment, the notification unit  75  performs the above-described notification by displaying a message on the screen of the touch panel  23 . 
     The notification unit  75  can perform the above-described notification using the determination result of the determination unit  52 . With this, the controller  53  performs operation support of the radiography apparatus  10 . For example, the notification unit  75  notifies that the subject is in the detection effective region or that the subject is not in the detection effective region. In a case where the subject is not in the detection effective region, the notification unit  75  notifies that the subject is not in the detection effective region after the second recognition unit  62  recognizes the subject. In a case where the subject is not in the detection effective region and in a case where the subject is not recognizable by the second recognition unit  62 , the notification unit  75  notifies that the subject is not recognizable. 
     In addition, the notification unit  75  notifies of a direction for moving the radiation detection unit  15  to put the subject in the detection effective region. The notification unit  75  notifies of a distance for moving the radiation detection unit  15  to put the subject in the detection effective region. The notification unit  75  notifies of an orientation, a direction, or an angle of rotating or inclining the radiation detection unit to put the subject in the detection effective region. 
     The laboratory technician or the like can performs easily adjustment (re-disposition or the like) of at least one of the subject, the radiation detection unit  15 , or the radiation source  31  as necessary according to any one of various kinds of notification or a combination of a plurality of kinds of notification. As a result, the imaging part can be reliably radiographed without excess and deficiency by single imaging. 
     The radiography apparatus  10  configured as above operates as follows. As shown in  FIG. 9 , the main body  11  is moved to the patient&#39;s room that the patient  101  as a subject is present (Step S 101 ), and the main body  11  is disposed at a position generally appropriate for radiography. The laboratory technician or the like takes out the radiation detection unit  15  from the holder  24  and disposes the radiation detection unit  15  at a position according to an imaging part (Step S 102 ). For example, as shown in  FIG. 10 , the patient  101  as a subject is lying on the bed  102 , and the radiation detection unit  15  is disposed between the imaging part and the bed  102 . In this case, the first recognition unit  61  recognizes and traces the radiation detection unit  15  according to information obtained with the position sensor  48 , and in a case where the radiation detection unit  15  is substantially horizontal and stationary, the radiation source position controller  91  automatically moves the radiation source  31  at a position confronting the radiation detection unit  15  (Step S 103 ). When necessary, the main body position controller  92  automatically adjusts the position of the main body  11 . As a result, a distance D 1  between the generation point  103  of radiation and the radiation detection unit  15  becomes the SID set in advance according to the imaging part and the like, and the irradiation field  105  of radiation becomes a range including the detection effective region of the radiation detection unit  15 . A distance D 2  is a so-called source to object distance (SOD), and a distance D 3  is a thickness (body thickness) of a body in the imaging part of the patient  101 . 
     In a case where the radiation detection unit  15  and the radiation source  31  are disposed as described above, the first recognition unit  61  recognizes the radiation detection unit  15  (Step S 104 ), and the second recognition unit  62  recognizes the patient  101  as a subject (Step S 105 ). 
     That is, the imaging unit  35  images the patient  101  and the like and provides the camera image  121  to the first recognition unit  61  and the second recognition unit  62 . Then, in a case where the radiation detection unit  15  is captured in the camera image  121 , the first recognition unit  61  specifies the position and the like of the radiation detection unit  15  using at least one of the camera image  121  or information obtained with the position sensor  48 . In a case where the radiation detection unit  15  is not captured in the camera image  121 , such as a case where the radiation detection unit  15  is behind the patient  101 , or in a case where the radiation detection unit  15  is not captured to a degree enough for use in recognition of the radiation detection unit  15 , the first recognition unit  61  specifies the position and the like of the radiation detection unit  15  using information obtained with the position sensor  48 . With this, as a result, the first recognition unit  61  recognizes the detection effective region. The second recognition unit  62  specifies the position and the like of the patient  101 , in particular, the imaging part of the patient  101  using the camera image  121 . 
     In a case where the first recognition unit  61  and the second recognition unit  62  end the recognition processing, the determination unit  52  determines whether or not the imaging part of the patient  101  is in the detection effective region using the recognition results of the first recognition unit  61  and the second recognition unit  62  (Step S 106 ). 
     In a case where the imaging part of the patient  101  is in the detection effective region (Step S 106 : YES), the irradiation field controller  82  determines whether or not the irradiation field  105  is appropriate using the determination result (Step S 107 ). In a case where the irradiation field  105  is appropriate (Step S 107 : YES), the radiation source controller  81  validates exposure of radiation (Step S 108 ). In a case where the irradiation field  105  is not appropriate (Step S 107 : NO), the irradiation field controller  82  automatically adjusts the irradiation field  105  (Step S 108 ), and thereafter, the radiation source controller  81  validates exposure of radiation. For example, in a case where the imaging part is the chest  122  of the patient  101 , and as shown in  FIG. 10 , in a camera image  121 , in a case where the chest  122  is small with respect to the detection effective region (a region indicated by a marker  42 ), and a blank is large in a radiographic image, the irradiation field controller  82  adjusts the irradiation field  105  to a region  123  conforming to the chest  122 . In a case where exposure of radiation is validated, the radiation source controller  81  automatically sets imaging conditions and waits for an input of an exposure instruction from the laboratory technician or the like. Then, in a case where there is an input of the exposure instruction from the laboratory technician or the like, the radiation source controller  81  performs radiation exposure from the radiation source  31 , the radiation detection unit  15  acquires a radiographic image (Step S 111 ). 
     On the other hand, in a case where the imaging part of the patient  101  is not in the detection effective region (Step S 106 : NO), the notification unit  75  notifies of the effect by displaying a message on the screen of the touch panel  23  (Step S 112 ). For example, as shown in  FIG. 12 , a console  131  where the radiographic image and the like are displayed and an imaging condition setting portion  132  where the imaging conditions, such as the tube voltage and the tube current, are set are displayed on the screen of the touch panel  23 , and the notification unit  75  further displays a message  135  to the effect that the imaging part of the patient  101  is not in the detection effective region. When viewing the message  135 , the laboratory technician or the like can know that the imaging part of the patient  101  is not in the detection effective region, and radiography may fail. Accordingly, the laboratory technician or the like re-disposes the radiation detection unit  15  with respect to the patient  101  by moving the radiation detection unit  15  or the patient  101  (Step S 114 ). In a case where the imaging part of the patient  101  is not in the detection effective region, the radiation source controller  81  invalidates exposure of radiation (Step S 113 ), and prevents erroneous exposure of radiation. In a case where re-disposition of the radiation detection unit  15  and the like is performed, the first recognition unit  61  and the second recognition unit  62  execute the recognition processing again. This loop is repeated until the determination unit  52  determines that the imaging part of the patient  101  is in the detection effective region. 
     As described above, the radiography apparatus  10  recognizes the radiation detection unit  15  and the patient  101  (in particular, the imaging part) as a subject and determines whether or not the patient  101  is in the detection effective region. Then, the controller  53  performs the adjustment of the irradiation field  105 , the validation or invalidation of exposure, the notification of the message for prompting re-disposition, and the like using the determination result to perform operation support of the radiography apparatus  10 . As a result, with the radiography apparatus  10 , it is possible to support reliable radiography even though the radiation source  31  and the radiation detection unit  15  are movable independently. That is, it is possible to reliably obtain a radiographic image of an imaging part to be imaged by single radiography. 
     The movement of the radiation source  31  of Step S 103  can be performed manually. Even though the radiation source  31  is manually moved to the position confronting the radiation detection unit  15 , the radiation source position controller  91  may automatically make fine adjustment on the position of the radiation source  31 . This is because accurate alignment (including the adjustment of the SID) can be supported. Similarly, the position adjustment of the main body  11  can be performed manually. Even though the main body  11  is manually moved, the main body position controller  92  may automatically make fine adjustment on the position of the main body  11 . This is because accurate alignment can be supported. In addition, at least one of the setting of the imaging conditions by the radiation source controller  81 , insertion and extraction of the filter  36  by the filter insertion-extraction controller  83 , and the like can be performed manually, and even though these are manually set or the like, it is possible to automatically perform fine adjustment of setting and the like. This is because accurate setting and the like are supported. That is, a part of the matters that are performed automatically by the radiography apparatus  10  in the above-described first embodiment can be performed manually. Furthermore, it is possible to support accurate setting and the like of setting matters and the like, which are performed manually, through fine adjustment or the like in the radiography apparatus  10 . 
     Second Embodiment 
     In the first embodiment, although the imaging unit  35  is provided in the distal end portion  13 , as shown in  FIG. 13 , a time of flight camera (TOF camera)  201  can be provided instead of the imaging unit  35  or in addition to the imaging unit  35 . 
     The TOF camera  201  is a camera that emits near infrared light in a pulsed manner and measures a reflection time of near infrared light from the subject. For this reason, in a case where the TOF camera  201  is provided, a body thickness measurement unit  202  that measures a body thickness (distance D 3 ) of the imaging part of the patient  101  using an image (hereinafter, referred to as a distance image) output from the TOF camera  201  is provided in, for example, the main body  11 . The distance image is, for example, an image in which each pixel has a pixel value having correlation with a distance from the TOF camera  201 . The body thickness measurement unit  202  measures the body thickness (distance D 3 ) distance image, by obtaining the distance D 2  from the generation point  103  of radiation to the imaging part of the patient  101  and subtracting the distance D 2  from the distance D 1  as the SID. 
     In a case where the radiography apparatus  10  has the TOF camera  201 , and the body thickness measurement unit  202  measures the body thickness of the subject, as shown in  FIG. 14 , for example, after the determination (Step S 106 ) regarding whether or not the subject is in the detection effective region, a body thickness measurement step S 211  of measuring the body thickness of the subject and an imaging condition setting step S 212  of setting imaging conditions using the body thickness of the subject can be included. The body thickness measurement step S 211  is a step including capturing of the distance image by the TOF camera  201  and body thickness measurement by the body thickness measurement unit  202 . The imaging condition setting step S 212  is a step in which, in a case where the subject is in the detection effective region, the controller  53  automatically sets the imaging conditions related to the body thickness of the subject using the body thickness of the subject. The setting of the imaging conditions includes changing or adjusting an imaging condition (a preset imaging condition or a manually set imaging condition) already set, in addition to newly setting an imaging condition. The imaging conditions related to the body thickness of the subject are, for example, the setting of the tube voltage of the radiation source  31  (in the embodiment, the X-ray tube), insertion and extraction of the filter  36 , and the like. That is, in the imaging condition setting step S 212 , the controller  53  sets the tube voltage of the radiation source  31  using the body thickness of the subject. Furthermore, in the imaging condition setting step S 212 , the controller  53  inserts or extracts the filter  36  between the radiation source  31  and the subject using the body thickness of the subject. 
     More specifically, the radiation source controller  81  increases the tube voltage according to the body thickness of the subject in the imaging condition setting step S 212 . With this, penetration of radiation is increased, and even though the body thickness of the subject is large, a clear radiographic image is obtained. On the other hand, in the imaging condition setting step S 212 , the filter insertion-extraction controller  83  inserts the filter  36  into the exposure path in a case where the tube voltage is equal to or greater than a predetermined threshold value. With this, exposure to the subject is reduced by shielding radiation having low penetration and low energy that does not contribute to a radiographic image. 
     As described above, in a case where the radiography apparatus  10  is configured to measure the body thickness of the patient  101  as the subject, the controller  53  can perform operation support of the radiography apparatus  10  using the determination result of the determination unit  52  and the body thickness of the patient  101  measured by the body thickness measurement unit  202 . Specifically, the controller  53  can automatically and appropriately set the imaging conditions using the body thickness of the patient  101  as the subject as described above in a case where the patient  101  as the subject is in the detection effective region. 
     Third Embodiment 
     In the above-described first embodiment and the like, in a case where the subject is not in the effective detection region, the effect is notified to prompt re-disposition (Step S 114 ). In contrast, in a case where re-disposition is required, the radiography apparatus  10  can more efficiently support re-disposition of the radiation source  31 , the radiation detection unit  15 , or the subject. For example, as shown in  FIG. 15 , the controller  53  can notify of a direction for moving the radiation detection unit  15  with respect to the subject using a message  301  or the like with the notification unit  75 . When viewing the message  301 , the laboratory technician or the like can easily re-dispose the radiation detection unit  15  with respect to the subject compared to a case where the message  301  is not provided. As a result, it is possible to put the subject in the effective detection region in a short time and accurately. 
     In addition, the controller  53  can notify of a distance for moving the radiation detection unit  15  with the notification unit  75  as well as the moving direction of the radiation detection unit  15 . In this case, it is possible to put the subject in the effective detection region in a shorter time and more accurately compared to a case where only the direction for moving the radiation detection unit  15  is notified. 
     As described above, in a case where re-disposition of the radiation detection unit  15  and the like is required, the controller  53  notifies of the direction and the distance for moving the radiation detection unit  15  with the notification unit  75 . This is particularly useful in a case where the controller  53  automatically moves the radiation source  31  to the position confronting the radiation detection unit  15  with the radiation source position controller  91 . This is because the radiation source position controller  91  automatically re-disposes the radiation source  31  following re-disposition of the radiation detection unit  15 , and thus, with just moving the radiation detection unit  15 , it is possible to put the subject in the effective detection region and re-disposition is completed. 
     In a case of manually moving the radiation source  31 , as shown in  FIG. 16 , the controller  53  can notify of a direction for moving the radiation source  31  using a message  310  or the like with the notification unit  75 . In addition, the controller  53  can further notify of a distance for moving the radiation source  31  with the notification unit  75 . With this, it is possible to easily complete re-disposition even in a case of manually moving the radiation source  31 . 
     In a case of manually moving the radiation source  31 , the controller  53  can notify that the radiation source  31  is at the position confronting the radiation detection unit  15 , using message display, voice, light, or other methods with the notification unit  75 . In a case where the notification unit  75  notifies that the radiation source  31  is at the position confronting the radiation detection unit  15 , the laboratory technician or the like can more easily complete re-disposition of the radiation source  31 . 
     In a case of manually moving the radiation source  31 , the controller  53  can regulate a moving direction of the radiation source  31  with the radiation source position controller  91 . For example, the radiation source position controller  91  permits movement in a direction in which the radiation source  31  approaches the position confronting the radiation detection unit  15 , but regulates movement in a direction in which the radiation source  31  goes away from the position confronting the radiation detection unit  15 . With this, the laboratory technician or the like can complete re-disposition of the radiation source  31  by just moving the radiation source  31  in a direction in which the radiation source  31  can be naturally moved. The radiation source position controller  91  can physically regulate the movement of the radiation source  31  by an electromagnetic lock or the like of the arm portion  12 . In addition, the radiation source position controller  91  can regulate substantial movement of the radiation source  31  by notification of an alert with the notification unit  75 , guidance of the moving direction of the radiation source  31 , or the like. 
     In the above-described third embodiment, although an operation support aspect on the re-disposition of the radiation detection unit  15  and the radiation source  31  has been described, in a case where the subject can be moved, the radiography apparatus  10  can perform support of notification of a moving direction or the like as above for the subject. 
     In the above-described third embodiment, although a case where at least one of the radiation detection unit  15 , the radiation source  31 , or the subject is re-disposed has been described, operation support of the third embodiment can also be performed in a case of initially disposing the radiation detection unit  15  or the like. That is, the invention is not limited to a case of re-disposing the radiation detection unit  15  or the like, and in a case of manually moving the radiation source  31 , the controller  53  can notify that the radiation source  31  is at the position confronting the radiation detection unit  15 . In addition, in a case of manually moving the radiation source  31 , the controller  53  can notify of a direction for moving the radiation source  31 . The same applies to others. In any cases, disposition of at least one of the radiation detection unit  15 , the radiation source  31 , or the subject is facilitated. 
     In the first embodiment, the second embodiment, and the third embodiment, and the like described above, in a case where the radiation detection unit  15  is attached to the main body  11  including the controller  53  (a case where the radiation detection unit  15  is in the holder  24 ), the controller  53  restricts the movement of the radiation source  31 . That is, the radiation source position controller  91  does not move the radiation source  31  in a case where the radiation detection unit  15  is attached to the main body  11  including the controller  53 . In addition, in a case where the radiation source  31  is movable manually, the radiation source position controller  91  restricts the movement of the radiation source  31 . This is to secure safety, for example, to prevent the distal end portion  13  including at least one of the arm portion  12  or the radiation source  31  from colliding with the laboratory technician, the subject, other hospital equipment, or the like. 
     In a case where the main body  11  including the controller  53  is moving, the controller  53  restricts the movement of the radiation source  31 . That is, the radiation source position controller  91  does not move the radiation source  31  in a case where the main body  11  is moving. In addition, in a case where the radiation source  31  is movable manually, the radiation source position controller  91  restricts the movement of the radiation source  31 . This is to secure safety, for example, to prevent the distal end portion  13  including at least one of the arm portion  12  or the radiation source  31  from colliding with the laboratory technician, the subject, other hospital equipment, or the like as above. 
     In a case where a sensor that detects a surrounding object, such as an infrared sensor, is provided in the distal end portion  13  or the like, the controller  53  may restrict the movement of the radiation source  31  in a case where the sensor detects a surrounding object. The reason is the same as above. 
     In the first embodiment, the second embodiment, the third embodiment, and the like described above, although the imaging unit  35  is provided in the distal end portion  13 , the imaging unit  35  can be provided in any portion other than the distal end portion  13  as long as the subject in the irradiation field  105  can be imaged. 
     In the first embodiment, the second embodiment, the third embodiment, and the like described above, although the arm portion  12  is a foldable type, the invention can be applied to a radiography apparatus  401  in which, as shown in  FIG. 17 , an arm portion  12  moves rotationally and expands and contracts (so-called telescopic arm). Although the radiography apparatus  10  and the radiography apparatus  410  are so-called treatment carts, the invention can be applied to a radiography apparatus or the like in which a part of the configuration of the radiography apparatus  10  and the like is fixed in a laboratory or the like. 
     The above-described first embodiment and the like include a radiography system comprising the radiation source  31  that generates radiation, the radiation detection unit  15  that is movable independently with respect to the radiation source  31  and obtains the image of the subject by detecting radiation transmitted through the subject, the imaging unit  35  that images at least the subject using light having a wavelength longer than radiation, the first recognition unit  61  that recognizes the radiation detection unit  15 , the second recognition unit  62  that recognizes the subject using the image captured by the imaging unit  35 , the determination unit  52  that, using the recognition results of the first recognition unit  61  and the second recognition unit  62 , specifies the relative positional relationship between the radiation detection unit  15  and the subject and determines whether or not the subject is in the detection effective region of the radiation detection unit  15 , and the controller  53  that performs operation support using the determination result of the determination unit  52 . The radiography system is not limited to a mobile type (treatment cart), and includes a system that has a part of components fixed in a laboratory or the like. 
     The above-described first embodiment and the like include an operation method of the radiography apparatus or the radiography system having the radiation source  31  that generates radiation, the radiation detection unit  15  that is movable independently with respect to the radiation source  31  and obtains the image of the subject by detecting radiation transmitted through the subject, and the imaging unit  35  that images at least the subject using light having a wavelength longer than radiation, the operation method of the radiography apparatus or the radiography system comprising a step in which the first recognition unit  61  recognizes the radiation detection unit  15 , a step in which the second recognition unit  62  recognizes the subject using the image captured by the imaging unit  35 , a step in which, using the recognition results of the first recognition unit  61  and the second recognition unit  62 , the determination unit  52  specifies the relative positional relationship between the radiation detection unit  15  and the subject and determines whether or not the subject is in the detection effective region of the radiation detection unit  15 , and a step in which the controller  53  performs operation support using the determination result of the determination unit  52 . 
     In the above-described embodiments and the like, the hardware structures of the processing units that execute various kinds of processing, such as the recognition unit  51  (the first recognition unit  61  and the second recognition unit  62 ) and the controller  53  (the imaging controller  71 , the radiation controller  72 , the position controller  73 , the notification unit  75 , and each unit constituting them), are various processors described below. Various processors include a central processing unit (CPU) that is a general-purpose processor executing software (program) to function as various processing units, a programmable logic device (PLD) that is a processor capable of changing a circuit configuration after manufacture, such as a graphical processing unit (GPU) or a field programmable gate array (FPGA), a dedicated electric circuit that is a processor having a circuit configuration dedicatedly designed for executing various kinds of processing, and the like. 
     One processing unit may be configured of one of various processors described above or may be configured of a combination of two or more processors (for example, a plurality of FPGAs, a combination of a CPU and an FPGA, a combination of a CPU and a GPU, or the like) of the same type or different types. A plurality of processing units may be configured of one processor. As an example where a plurality of processing units are configured of one processor, first, as represented by a computer, such as a client or a server, there is a form in which one processor is configured of a combination of one or more CPUs and software, and the processor functions as a plurality of processing units. Secondly, as represented by system on chip (SoC) or the like, there is a form in which a processor that implements all functions of a system including a plurality of processing units into one integrated circuit (IC) chip is used. In this way, various processing units may be configured using one or more processors among various processors described above as a hardware structure. 
     In addition, as the hardware structure of various processors, more specifically, an electric circuit (circuitry), in which circuit elements, such as semiconductor elements, are combined can be used. 
     EXPLANATION OF REFERENCES 
     
         
         
           
               10 ,  401 : radiography apparatus 
               11 : main body 
               12 : arm portion 
               13 : distal end portion 
               15 : radiation detection unit 
               21 : caster 
               22 : grip portion 
               23 : touch panel 
               24 : holder 
               31 : radiation source 
               32 : collimator 
               33 : handle 
               35 : imaging unit 
               36 : filter 
               41 ,  42 : marker 
               43 : position sensor 
               46 : image acquisition unit 
               47 ,  54 : communication unit 
               48 : position sensor 
               49 , 57 : battery 
               51 : recognition unit 
               52 : determination unit 
               53 : controller 
               56 : storage unit 
               61 : first recognition unit 
               62 : second recognition unit 
               64 : template 
               64   a : chest 
               65 A,  65 B: comparison range 
               71 : imaging controller 
               72 : radiation controller 
               73 : position controller 
               75 : notification unit 
               81 : radiation source controller 
               82 : irradiation field controller 
               83 : filter insertion-extraction controller 
               91 : radiation source position controller 
               92 : main body position controller 
               101 : patient 
               102 : bed 
               103 : generation point 
               105 : irradiation field 
               121 : camera image 
               122 : chest 
               123 : region 
               131 : console 
               132 : imaging condition setting portion 
               135 ,  301 ,  310 : message 
               201 : TOF camera 
               202 : body thickness measurement unit 
             D 1 , D 2 , D 3 : distance 
             S 101  to S 111 , S 211 , S 212 : step of operation