Patent Publication Number: US-2011049370-A1

Title: Radiographic image capturing apparatus, radiographic image capturing system, and radiographic image capturing method

Description:
CROSS-REFERENCE TO RELATED APPLICATION 
     This application is based upon and claims the benefit of priority from Japanese Patent Application No. 2009-194679 filed on Aug. 25, 2009, of which the contents are incorporated herein by reference. 
     BACKGROUND OF THE INVENTION 
     1. Field of the Invention 
     The present invention relates to a radiographic image capturing apparatus, a radiographic image capturing system, and a radiographic image capturing method for applying a radiation from a radiation source to a subject and detecting the radiation that has passed through the subject and converting the detected radiation into a radiation image with a radiation detector. 
     2. Description of the Related Art 
     In the medical field, there have widely been used radiographic image capturing apparatus which apply a radiation to a subject and guide the radiation that has passed through the subject to a radiation conversion panel (radiation detector), which captures a radiographic image from the radiation. Known forms of the radiation conversion panel include a conventional radiation film for recording a radiographic image by way of exposure, and a stimulable phosphor panel for storing a radiation energy representing a radiographic image in a phosphor and reproducing the radiographic image as stimulated light by applying stimulating light to the phosphor. The radiation film with the recorded radiographic image is supplied to a developing device to develop the radiographic image, or the stimulable phosphor panel is supplied to a reading device to read the radiographic image as a visible image. 
     In the operating room or the like, it is necessary to read a recorded radiographic image immediately from a radiation conversion panel after the radiographic image is captured for the purpose of quickly and appropriately treating the patient. As a radiation detector which meets such a requirement, there have been developed a radiation detector of the direct conversion type having a solid-state detector for converting a radiation directly into an electric signal and a radiation detector of the indirect conversion type having a scintillator for temporarily converting a radiation into visible light and a solid-state detector for converting the visible light into an electric signal. 
     The radiation detector described above is housed in a radiation detecting cassette which is permeable to the radiation. 
     As disclosed in Japanese Laid-Open Patent publication No. 2003-093354, the radiographic image capturing apparatus are developed on the assumption that they will be used to capture radiographic images of patients in hospitals. 
     There are potential demands for capturing radiographic images outside hospitals. To meet such demands, radiographic image capturing apparatus mounted on motor vehicles dedicated for medical examination have been proposed in the art (see Japanese Laid-Open Patent Publication No. 2008-206740 and Japanese Laid-Open Patent Publication No. 2002-306463). However, the proposed radiographic image capturing apparatus on the medical examination motor vehicles are relatively large in size. Needs have arisen for capturing radiographic images of persons who suffer from natural disasters at disaster sites or persons who are receiving home-care services at their homes. However, the existing medical examination motor vehicles cannot be used in the former application as they find it difficult to get to disaster sites. Though the existing medical examination motor vehicles may be driven to the homes of persons who are receiving home-care services, the image capturing process is highly burdensome to the people to be imaged because they have to be taken from their homes into the medical examination motor vehicle in order to capture radiographic images thereof. Therefore, there have been demands for small-size portable radiographic image capturing apparatus for use at natural disaster sites or homes receiving home-care services. 
     There has been developed a portable radiographic image capturing apparatus which can be folded into a compact form in its entirety as disclosed in Japanese Laid-Open Patent Publication No. 11-104117. In addition, field-emission-type radiation sources based on the carbon nanotube (CNT) technology have been proposed as disclosed in Japanese Laid-Open Patent Publication No. 2007-103016 and AIST: Press Release “Development of Portable X-ray Sources Using Carbon Nanostructures” [online], Mar. 19, 2009, National Institute of Advanced Industrial Science and Technology, [retrieved Jul. 8, 2009, Internet &lt;URL: http://www.aist.go.jp/aist_j/press_release/pr2009/pr20090319/pr20090319.html&gt;. It has been expected to have small-size, lightweight radiographic image capturing apparatus including radiation sources, available in the art. 
     When a radiographic image capturing apparatus including a radiation source is reduced in overall size and weight, it is easy to carry around. Specifically, a radiographic image capturing apparatus is carried to a disaster site or a home receiving home-care services. At the disaster site or the home, the radiographic image capturing apparatus is assembled into an operational form so that it is ready to capture radiographic images. 
     In Japan, persons who are legally permitted to engage in the business of applying a radiation to a human body (to capture a radiographic image of the human body) are limited to doctors and dentists (hereinafter simply referred to as “doctors”) and medical radiological technicians (hereinafter simply referred to as “radiological technicians”) according to the Radiology Technicians Act. If a doctor or a radiological technician who has the legal authority about the application of a radiation to a subject is unable to go to a disaster site or a home receiving home-care services for some reasons, then a person other than the doctor or the radiological technician, i.e., a person who is not qualified as a radiological technician according to the Radiology Technicians Act (hereinafter referred to as “operator”), may take a radiographic image capturing apparatus to the site and perform a preparatory procedure to make the radiographic image capturing apparatus ready to capture radiographic images, e.g., to position a body region of the subject to be imaged with respect to the cassette housing the radiation detector. However, the operator is not legally permitted to capture radiographic images of the subject with the radiographic image capturing apparatus. According to the present practice, the qualified person such as a doctor or a radiological technician needs to go to the disaster site or the home in order to capture radiographic images of the subject with the radiographic image capturing apparatus. 
     To eliminate the above shortcomings, the technologies disclosed in Japanese Laid-Open Patent Publication No. 2003-093354 and Japanese Laid-Open Patent Publication No. 2008-206740 may be applied to capture radiographic images of a subject according to the instructions from a doctor or a radiological technician who is staying in a place (e.g., a medical organization or a medical examination motor vehicle) where they cannot see the subject directly. 
     According to the technology disclosed Japanese Laid-Open Patent Publication No. 2003-093354, an image (radiographic image) of the affected region of an emergency patient (subject) who has been carried into a medical organization is sent to the mobile terminal of a doctor who is not available at the medical organization, and the doctor is asked to give instructions as to a next radiographic image of the emergency patient to be captured. If the technology disclosed Japanese Laid-Open Patent Publication No. 2003-093354 is directly applied, then the image of the affected region of the emergency patient which is sent to the mobile terminal of the doctor to seek the doctor&#39;s instructions as to a next radiographic image to be captured may possibly be a radiographic image which has been captured without the approval of the doctor. In addition, since the image of the affected region of the emergency patient needs to be sent to the mobile terminal of the doctor to seek the doctor&#39;s instructions as to a next radiographic image to be captured, the doctor is unable to instruct any person at the site to capture a radiographic image of the patient in real time. 
     According to the technology disclosed in Japanese Laid-Open Patent Publication No. 2008-206740, the exposure of a subject to a radiation is interrupted based on an optical image representing a body movement of the subject. Even if the technology disclosed in Japanese Laid-Open Patent Publication No. 2008-206740 is directly applied, the doctor is unable to instruct any person at the site to capture a radiographic image of the patient in real time. 
     SUMMARY OF THE INVENTION 
     It is an object of the present invention to provide a radiographic image capturing apparatus, a radiographic image capturing system, and a radiographic image capturing method which make it possible to capture a radiographic image of a subject at a disaster site or a home receiving home-care services even without the need for a doctor or a radiological technician to go to the disaster site or the home. 
     To achieve the above object, there is provided in accordance with the present invention a radiographic image capturing apparatus comprising a radiation source for outputting a radiation, a radiation detector for detecting the radiation which is transmitted through a subject when the subject is irradiated with the radiation by the radiation source, and converting the detected radiation into a radiographic image, a cassette housing the radiation detector therein, the cassette being permeable to the radiation, a camera for capturing an image of at least the cassette, and a camera image communication unit for sending the image of the cassette which is captured by the camera to a waiting-place communication unit, the waiting-place communication unit being disposed in a waiting place where a doctor or radiological technician who has the legal authority about the application of the radiation to the subject waits and is unable to see the subject directly. 
     There is also provided in accordance with the present invention a radiographic image capturing system comprising a radiographic image capturing apparatus including a radiation source for outputting a radiation, a radiation detector for detecting the radiation which is transmitted through a subject when the subject is irradiated with the radiation by the radiation source, and converting the detected radiation into a radiographic image, a cassette housing the radiation detector therein, the cassette being permeable to the radiation, a camera for capturing an image of at least the cassette, and a camera image communication unit for sending the image of the cassette which is captured by the camera to an external circuit, a waiting-place communication unit for receiving the image of the cassette from the camera image communication unit, the waiting-place communication unit being disposed in a waiting place where a doctor or radiological technician who has the legal authority about the application of the radiation to the subject waits and is unable to see the subject directly, and a console electrically connected to the waiting-place communication unit, for being supplied with the image of the cassette from the waiting-place communication unit. 
     There is further provided in accordance with the present invention a radiographic image capturing method comprising the steps of capturing an image of a cassette housing therein at least a radiation detector with a camera, sending the image of the cassette which is captured by the camera to a waiting-place communication unit which is disposed in a waiting place where a doctor or radiological technician who has the legal authority about the application of a radiation to a subject waits and is unable to see the subject directly, sending an instruction from the waiting-place communication unit to the radiation source to output the radiation thereby to cause the radiation source to output and apply the radiation to the subject, when the image of the cassette sent to the waiting-place communication unit includes a body region of the subject to be imaged, and detecting the radiation which is transmitted through the subject and the cassette and converting the detected radiation into a radiographic image with the radiation detector. 
     According to the present invention, at a disaster site or a home receiving home-care services, the camera captures an image of at least the cassette, and the camera image communication unit sends the image of the cassette which is captured by the camera to the waiting-place communication unit in the waiting place. Based on the image of the cassette which is received by the waiting-place communication unit, the doctor or radiological technician who is waiting in the waiting place where the doctor or radiological technician is unable to see the subject directly can instruct the operator of the radiographic image capturing apparatus at the disaster site or the home to capture a radiographic image of the subject in real time. Therefore, the doctor or radiological technician can capture a radiographic image of the subject without going themselves to the disaster site or the home. 
     The above and other objects, features, and advantages of the present invention will become more apparent from the following description when taken in conjunction with the accompanying drawings in which preferred embodiments of the present invention are shown by way of illustrative example. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  is a perspective view of a radiographic image capturing apparatus and a radiographic image capturing system according to an embodiment of the present invention; 
         FIG. 2  a perspective view of the radiographic image capturing apparatus shown in  FIG. 1 ; 
         FIG. 3  is a side elevational view of the radiographic image capturing apparatus shown in  FIGS. 1 and 2 ; 
         FIG. 4  is a side elevational view of the radiographic image capturing apparatus shown in  FIGS. 1 and 2 ; 
         FIG. 5  is a perspective view showing the manner in which the radiographic image capturing apparatus shown in  FIGS. 1 and 2  is carried; 
         FIG. 6  is a cross-sectional view, partly shown in block form, of internal details of a radiation source device shown in  FIG. 1 ; 
         FIG. 7  is a plan view, partly in cross section, of a cassette shown in  FIGS. 1 and 2 ; 
         FIG. 8  is a schematic view showing an array of pixels of a radiation detector of the radiographic image capturing apparatus shown in  FIG. 1 ; 
         FIG. 9  is a block diagram of a circuit arrangement of the radiation detector in the cassette; 
         FIG. 10  is a block diagram of the radiographic image capturing apparatus shown in  FIG. 1 ; 
         FIG. 11  is a block diagram of a medical organization shown in  FIG. 1 ; 
         FIG. 12  is a flowchart of an image capturing sequence of the radiographic image capturing apparatus and the radiographic image capturing system shown in  FIG. 1 ; 
         FIG. 13  is a flowchart of a preparatory procedure in step S 5  shown in  FIG. 12 ; 
         FIGS. 14A through 14C  are views showing by way of example images displayed on a mobile information terminal and/or a console; 
         FIGS. 15A through 15C  are views showing by way of example images displayed on the mobile information terminal and/or the console; 
         FIG. 16  is a perspective view showing the manner in which the mobile information terminal, the radiation source device, and the cassette are charged in the medical organization; 
         FIG. 17  is a perspective view of a radiographic image capturing apparatus and a radiographic image capturing system according to a first modification; 
         FIG. 18  is a perspective view of a radiographic image capturing apparatus and a radiographic image capturing system according to a second modification; 
         FIG. 19  is a perspective view of a radiographic image capturing apparatus and a radiographic image capturing system according to a third modification; 
         FIG. 20  is a perspective view of a radiographic image capturing apparatus and a radiographic image capturing system according to a fourth modification; 
         FIG. 21  is a perspective view of a radiographic image capturing apparatus and a radiographic image capturing system according to a fifth modification; 
         FIG. 22  is a perspective view of a radiographic image capturing apparatus and a radiographic image capturing system according to a sixth modification; 
         FIG. 23  is a perspective view of a radiographic image capturing apparatus and a radiographic image capturing system according to a seventh modification; 
         FIG. 24  is a perspective view of a radiographic image capturing apparatus and a radiographic image capturing system according to an eighth modification; 
         FIG. 25  is a perspective view of a radiographic image capturing apparatus and a radiographic image capturing system according to a ninth modification; 
         FIGS. 26A and 26B  are views of a portion of a radiographic image capturing apparatus and a radiographic image capturing system according to a tenth modification; 
         FIGS. 27A and 27B  are views of a portion of the radiographic image capturing apparatus and the radiographic image capturing system according to the tenth modification; 
         FIGS. 28A and 28B  are views of a portion of the radiographic image capturing apparatus and the radiographic image capturing system according to the tenth modification; 
         FIGS. 29A and 29B  are views of a portion of the radiographic image capturing apparatus and the radiographic image capturing system according to the tenth modification; 
         FIGS. 30A and 30B  are views of a portion of the radiographic image capturing apparatus and the radiographic image capturing system according to the tenth modification; 
         FIG. 31A  is a cross-sectional view of a portion of a radiographic image capturing apparatus; 
         FIG. 31B  is a view showing by way of example an image displayed on a mobile information terminal and/or a console of the radiographic image capturing apparatus shown in  FIG. 31A ; 
         FIG. 32A  is a cross-sectional view of a portion of a radiographic image capturing apparatus; 
         FIG. 32B  is a view showing by way of example an image displayed on a mobile information terminal and/or a console of the radiographic image capturing apparatus shown in  FIG. 32A ; 
         FIG. 33A  is a view showing by way of example an image displayed on the mobile information terminal and/or the console after a radiographic image has been captured by the radiographic image capturing apparatus shown in  FIG. 31A ; 
         FIG. 33B  is a view showing by way of example an image displayed on the mobile information terminal and/or the console after a radiographic image has been captured by the radiographic image capturing apparatus shown in  FIG. 32A ; 
         FIG. 34  is a view of a portion of the radiographic image capturing apparatus and the radiographic image capturing system according to the eleventh modification; 
         FIG. 35  is a perspective view of the radiation source device shown in  FIG. 34 ; 
         FIGS. 36A and 36B  are cross-sectional views of a portion of a radiographic image capturing apparatus; and 
         FIGS. 37A and 37B  are perspective views of other examples of the radiation source device shown in  FIG. 35 . 
     
    
    
     DESCRIPTION OF THE PREFERRED EMBODIMENTS 
     Radiographic image capturing apparatus and radiographic image capturing systems incorporating such radiographic image capturing apparatus according to preferred embodiments of the present invention, in relation to radiographic image capturing methods carried out thereby, will be described in detail below with reference to  FIGS. 1 through 37B . 
     As shown in  FIGS. 1 and 2 , a radiographic image capturing apparatus  10  as part of a radiographic image capturing system  11  according to an embodiment of the present invention includes a radiation source device  16  housing therein a radiation source  14  for emitting a radiation  12  and made of a material permeable to the radiation  12 , a cassette  22  housing therein a radiation detector  20  (see  FIGS. 3 and 4 ) for converting the radiation  12  that has passed through a subject  18  into a radiographic image and made of a material permeable to the radiation  12 , and a mobile information terminal (controller, PC)  34  electrically connected to the radiation source device  16  by a USB cable (communication cable)  24 , electrically connected to the cassette  22  by a USB cable (communication cable)  26 , and incorporating a web camera  30  for capturing an image of a predetermined imaging area  28 . The mobile information terminal  34  can be operated by an operator  32  (see  FIG. 5 ) of the radiographic image capturing apparatus  10 . The mobile information terminal  34  is capable of sending signals to and receiving signals from a medical organization  40  (waiting place) to which a doctor (or a radiological technician)  38  belongs, via a network  36  such as a public network or the like, by way of wireless communications. 
     The operator  32  refers to a person who is no qualified as a medical radiological technician according to the Radiology Technicians Act of Japan, or specifically a person other than doctors and dentists (hereinafter simply referred to as “doctors”) and medical radiological technicians (hereinafter simply referred to as “radiological technicians”) who have the legal authority about the application of the radiation  12  to the subject  18 . In the present embodiment, the subject  18  is present at a disaster site or a home receiving home-care services, whereas the doctor (or radiological technician)  38  is present (waiting) in a remote medical organization  40  where the doctor (or radiological technician)  38  is unable to directly see the subject  18 . The doctor (or radiological technician)  38  is unable to go to the disaster site or the home for some reasons, and the operator  32  goes in lieu of the doctor  38  to the disaster site or the home. Hereinafter, the reference numeral  38  will be used to represent a doctor. 
     As shown in  FIGS. 1 through 4  and  7 , the cassette  22  has a substantially rectangular housing  42  made of a material permeable to the radiation  12  and including a surface facing the radiation source device  16 . The surface facing the radiation source device  16  will be referred to as an irradiated surface  44  which is irradiated with the radiation  12 . The cassette  22  has guide lines  46  disposed in an irradiated area (irradiated field), which is irradiated with the radiation  12 , of the irradiated surface  44  and serving as a reference for an image capturing area and an image capturing position. The guide lines  46  provide an outer frame (irradiated field) which is substantially aligned with the outer edge of the radiation detector  20 , as shown in  FIG. 7 . One side  48  of the housing  42  supports a switch  50  for activating the cassette  22  and is connected to a connector  52  on one end of the USB cable  26 . 
     As shown in  FIGS. 3 and 6 , the radiation source device  16  has a substantially cylindrical casing  130  made of a material permeable to the radiation  12 , the substantially cylindrical casing  130  being substantially rectangular in cross section. The casing  130  houses therein the radiation source  14  and an irradiated field lamp  56  for emitting irradiation light  54 . The irradiated field lamp  56  applies the irradiation light  54  to the irradiated surface  44  before the radiation source  14  outputs the radiation  12 , thereby displaying the irradiated field on the irradiated surface  44 . 
     It is assumed that a straight line interconnecting a focused point  160 , to be described later, of the radiation source  14  and a central position of the guide lines  46  (see  FIGS. 1 ,  2 , and  7 ), i.e., a point of intersection of the criss-crossing guide lines  46 , is substantially perpendicular to the irradiated surface  44 . If the distance (imaging distance) between the focused point  160  and the central position of the crisscross guide lines  22  is set to a source-to-image distance (SID), then the outer edge of the irradiated field that is displayed on the irradiated surface  44  when the irradiation light  54  is applied thereto is essentially aligned with the outer frame of the guide lines  46 . The portion of the casing  130  through which the irradiation light  54  passes should preferably be made of a material permeable to the irradiation light  54 . As shown in  FIGS. 1 ,  2 , and  6 , the casing  130  has a side connected to a connector  58  on one end of the USB cable  24 . 
     As shown in  FIGS. 1 through 4  and  16 , the mobile information terminal  34  comprises a notebook-sized personal computer including an operating unit  60  such as a keyboard, etc., disposed on an upper surface (facing a lid  66 ) of a main body  62  and a display unit  64  disposed on a lower surface (facing the operating unit  60 ) of the lid  66 . In the present embodiment, the mobile information terminal  34  is illustrated as a notebook-sized personal computer. However, the mobile information terminal  34  may be one of any mobile terminals having various functions including the operating unit  60  and the display unit  64 , e.g., a mobile phone or a PDA (Personal Digital Assistant). 
     When the mobile information terminal  34  is not in use, the main body  62  and the lid  66  are folded one on the other about a shaft  68  on one side of the main body  62  and two hinges  70  connected to the respective ends of the shaft  68 , as shown in  FIG. 16 . The upper surface of the main body  62  has two teeth  72 , and the lower surface of the lid  66  has two recesses  74  corresponding to the respective teeth  72 . When the upper surface of the main body  62  and the lower surface of the lid  66  are brought into contact with each other at the time the mobile information terminal  34  is not in use, the teeth  72  fit respectively into the recesses  74 , keeping the main body  62  and the lid  66  folded one on the other. 
     When the mobile information terminal  34  is in use, the lid  66  is turned away from the main body  62  about the shaft  68  and the hinges  70 , unfolding the main body  62  and the lid  66  away from each other to an operational position shown in  FIGS. 1 through 4 . 
     On the upper surface of the main body  62  around the operating unit  60 , there are disposed a power supply switch  76  for activating the mobile information terminal  34 , speakers (sound output unit)  78  for outputting sounds, and a microphone  80  for detecting the voices of the subject  18  and the operator  32 . On a side of the main body  62 , there are disposed a USB terminal  84  (see  FIG. 16 ) for connecting to a connector  82  on the other end of the USB cable  24 , a USB terminal  88  for connecting to a connector  86  on the other end of the USB cable  26 , a USB terminal  90  for sending information to and receiving information from an external device, a card slot  94  for inserting a memory card  92  therein, and an input terminal  96  for connection to an AC adapter. 
     The lid  66  has on its upper surface the web camera  30  as an optical camera. The web camera  30  and the mobile information terminal  34  are integrally combined with each other. 
     The integral structure of the web camera  30  and the mobile information terminal  34  is not limited to the structure in which the mobile information terminal  34  has a built-in web camera  30  shown in  FIGS. 1 through 4 , but may include the structure in which a mobile information terminal  34  is integrally connected to a web camera  30  at least at the time the radiographic image capturing apparatus  10  is in use. Specifically, the integral structure of the web camera  30  and the mobile information terminal  34  includes the cases: (1) the web camera  30  and the mobile information terminal  34  are connected to each other by cables attached to the radiographic image capturing apparatus  10 ; (2) the web camera  30  and the mobile information terminal  34  are connected to each other by a cable prepared by the operator  32 ; and (3) the web camera  30  and the mobile information terminal  34  are connected to each other when in use, whereas the web camera  30  and the mobile information terminal  34  are separable from each other during maintenance or when not in use. 
     When the lid  66  is turned away from the main body  62  until the upper surface of the lid  66  faces the cassette  22 , the radiation source device  16 , and the subject  18 , and the operator  32  turns on the power supply switch  76  to activate the mobile information terminal  34 , the web camera  30  captures an image of at least the irradiated field (the range of the guide lines  46 ) of the irradiated surface  44  as the imaging area  28 . More preferably, as shown in  FIGS. 1 through 4 , while the subject  18  is being positioned between the radiation source device  16  and the cassette  22 , the web camera  30  captures an image of an area including the radiation source device  16 , the subject  18 , and the cassette  22  as the imaging area  28 . 
     The web camera  30  captures successive images of the imaging area  28  and outputs the captured successive images as camera images (moving images). The web camera  30  can also capture images of the imaging area  28  at intermittent intervals (intermittently) and output the captured images as camera images (still images) at intermittent intervals or output the captured images as camera images (still images) at predetermined times. 
       FIG. 5  shows the manner in which the radiographic image capturing apparatus  10  is carried by the operator  32 . 
     When the radiographic image capturing apparatus  10  is carried by the operator  32 , the radiation source device  16 , the cassette  22 , and the folded mobile information terminal  34  is housed in an attaché case  98  with the connectors  52 ,  58 ,  82 ,  86  removed to electrically disconnect the USB cables  24 ,  26 . The operator  32  can grip a handle  100  and carry the attaché case  98  from the medical organization  40  to a desired place, e.g., a disaster site or a home receiving home-care services. At the place to which attaché case  98  is carried, the operator  32  can take out the radiation source device  16 , the cassette  22 , and the folded mobile information terminal  34  from the attaché case  98 , and assemble them into the configuration shown in  FIGS. 1 through 4 . The operator  32  can then perform a preparatory procedure to make the radiographic image capturing apparatus  10  ready for capturing radiographic images of a person at a disaster site or a home receiving home-care services. 
     The radiographic image capturing apparatus  10  according to the present embodiment can thus be referred to as a portable radiographic image capturing apparatus integrally combined with the web camera  30  and the mobile information terminal  34 . The person who is to be imaged at a disaster site or a home receiving home-care services by the radiographic image capturing apparatus  10  will be referred to as the subject  18 . 
     As shown in  FIG. 1 , the medical organization  40  includes a communication unit (waiting-place communication unit, wireless communication unit)  104  having an antenna  102  for sending signals to and receiving signals from the mobile information terminal  34  via the network  36  by way of wireless communications. A console  106  is electrically connected to the communication unit  104 . 
     The console  106  is connected to a radiology information system (RIS), not shown, which generally manages radiographic images and other information that are handled in a radiological department of the medical organization  40 . The RIS is connected to a hospital information system (HIS), not shown, which generally manages medical information in the medical organization  40 . 
     The console  106  comprises a main body  108  for carrying out processing sequences, the main body  108  being placed on a desk  107  in a room attended by the doctor  38  in the medical organization  40 , a display unit  112  for displaying images and information for the doctor  38  seated on a chair  110  at the desk  107 , an operating unit  114  such as a keyboard, etc. operable by the doctor  38 , a web camera  116  mounted on the upper end of the display unit  112  for capturing an image of the doctor  38 , a speaker  118  for outputting sounds, an exposure switch  120  which can be turned on by the doctor  38  to instruct the radiation source  14  to emit the radiation  12 , and a microphone  122  for detecting the voice of the doctor  38 . 
     As described above, the mobile information terminal  34  and the communication unit  104  send signals to and receive signals from each other via the network  36  by way of wireless communications. 
     The mobile information terminal  34  can send a camera image output from the web camera  30 , a radiographic image supplied from the cassette  22  (radiation detector  20 ) via the USB cable  26 , and a sound signal representative of the voice of the operator  32  or the subject  18  detected by the microphone  80 , through the antenna  102  to the communication unit  104  via the network  36  by way of wireless communications. 
     The communication unit  104  can send a camera image (a moving image, still images captured intermittently, or a still image captured at a predetermined time) of the doctor  38  captured by the web camera  116 , an exposure control signal generated in the main body  108  when the doctor  38  turns on the exposure switch  120 , and a voice signal representing the voice of the doctor  38  detected by the microphone  122 , to the mobile information terminal  34  via the antenna  102  and the network  36  by way of wireless communications. 
     On the mobile information terminal  34 , the display unit  64  is thus able to display a camera image in the imaging area  28  captured by the web camera  30 , a radiographic image from the radiation detector  20 , and/or a camera image of the doctor  38  captured by the web camera  116 . The display unit  64  is also able to display information (character information) corresponding to the voice signals and the exposure control signal referred to above. The speakers  78  are able to output the voice of the doctor  38  and a sound depending on the exposure control signal (an alarm sound indicative of the start of the emission of the radiation  12  from the radiation source  14 ). 
     The mobile information terminal  34  sends a synchronization control signal generated based on the exposure control signal via the USB cables  24 ,  26  to the radiation source device  16  and the cassette  22  for thereby synchronizing the (start of) emission of the radiation  12  from the radiation source  14  and the detection and conversion of the radiation  12  into a radiographic image in the radiation detector  20  with each other. 
     On the console  106 , the display unit  112  is able to display a camera image in the imaging area  28  captured by the web camera  30 , a radiographic image from the radiation detector  20 , and/or a camera image of the doctor  38  captured by the web camera  116 , as is the case with the display unit  64 . The display unit  112  is also able to display information (character information) corresponding to the voice signals and the exposure control signal referred to above. The speaker  118  is able to output the voice of the operator  32  or the subject  18  and a sound depending on the exposure control signal. 
     Internal structures of the radiation source device  16  and the cassette  22  will be described in specific detail with reference to  FIGS. 6 through 9 . 
     As shown in  FIG. 6 , the casing  130  of the radiation source device  16  houses therein the radiation source  14 , the irradiated field lamp  56 , a USB terminal  132  for connecting to the connector  58  on the USB cable  24 , a battery  134  for supplying electric power to various components of the radiation source device  16 , the battery  134  being chargeable from an external circuit, e.g., the mobile information terminal  34 , via the USB cable  24 , the connector  58 , and the USB terminal  132 , a communication unit (radiation source communication unit)  136 , a radiation source controller  138  for controlling the radiation source  14 , a mirror  144  made of a material permeable to the radiation  12 , and a collimator  146  which is made of a material impermeable to the radiation  12 , but permeable to the irradiation light  54 . 
     The radiation source  14  comprises a field-emission-type radiation source similar to the field-emission-type radiation source disclosed in Japanese Laid-Open Patent Publication No. 2007-103016. 
     The radiation source  14  includes a disk-shaped rotary anode  152  mounted on a rotational shaft  150  that can be rotated about its own axis by a rotating mechanism  148 , an annular target layer  154  disposed on the surface of the rotary anode  152  and made mainly of a metallic element of Mo or the like, a cathode  156  disposed in confronting relation to the rotary anode  152 , and a field-emission-type electron source  158  disposed on the cathode  156  in confronting relation to the target layer  154 . 
     The radiation source controller  138  controls the radiation source  14  to output the radiation  12  according to a synchronization control signal based on an exposure control signal, which is received from the mobile information terminal  34  (see  FIGS. 1 through 5 ) via the USB cable  24 , the connector  58 , the USB terminal  132 , and the communication unit  136 . 
     Specifically, when the radiation source  14  is controlled by the radiation source controller  138 , the rotating mechanism  148  rotates the rotational shaft  150  to rotate the rotary anode  152 . The battery  134  supplies electric power to a power supply  142 , which applies a negative voltage to the field-emission-type electron source  158 . The battery  134  also supplies electric power to a power supply  140 , which applies a voltage between the rotary electrode  152  and the cathode  156 , i.e., applies a positive voltage to the rotary electrode  152  and applies a negative voltage to the cathode  156 . The field-emission-type electron source  158  emits electrons that are accelerated and bombard the target layer  154  under the voltage applied between the rotary electrode  152  and the cathode  156 . The electrons are focused onto and bombard a point  160  on the surface of the target layer  154 , and the bombarded surface of the target layer  154  emits the radiation  12  from the focused point  160  at an intensity level depending on the applied electrons. The radiation  12  passes through the mirror  144 , is constricted in its irradiation area by the collimator  146  and output from the radiation source device  16 . 
     Until the radiation source controller  138  is supplied with the synchronization control signal from the mobile information terminal  34 , the radiation source controller  138  controls the irradiated field lamp  56  to emit the irradiation light  54 . The irradiation light  54  emitted from the irradiated field lamp  56  is reflected by the mirror  144  to the collimator  146 , and is constricted in its irradiation area by the collimator  146  and output from the radiation source device  16 . 
     As shown in  FIGS. 3 ,  4 , and  7 , the cassette  22  houses therein a grid  162  for removing scattered rays of the radiation  12  from the subject  18  when the radiation source  14  applies the radiation  12  to the subject  18 , the radiation detector  20 , and a lead plate  164  for absorbing back scattered rays of the radiation  12 , which are successively arranged in the order named from the irradiated surface  44  of the cassette  22  which faces the subject  18 . The irradiated surface  44  of the cassette  22  may be constructed as the grid  162 . 
     The radiation detector  20  may comprise a radiation detector of the indirect conversion type including a scintillator for converting the radiation  12  having passed through the subject  18  into visible light and solid-state detectors (hereinafter also referred to as pixels) made of amorphous silicon (a-Si) or the like for converting the visible light into an electric signal, or a radiation detector of the direct conversion type comprising solid-state detectors made of amorphous selenium (a-Se) or the like for converting the dose of the radiation  12  directly into an electric signal. 
     The switch  50  and a USB terminal  172  for connecting to the connector  52  on the USB cable  26  are disposed on the side  48  of the cassette  22 . 
     The cassette  22  also houses therein a battery  166  for supplying electric power to various components of the cassette  22 , the battery  166  being chargeable from an external circuit, e.g., the mobile information terminal  34 , via the USB cable  26 , the connector  52 , and the USB terminal  172 , a cassette controller  168  for controlling the radiation detector  20  with electric power supplied from the battery  166 , and a communication unit  170  for sending and receiving signals including the information of the radiation  12  detected by the radiation detector  20 , to and from the mobile information terminal  34  via the USB terminal  172 , the connector  52 , and the USB cable  26 . 
     A plate of lead or the like should preferably be placed over the side surfaces of the cassette controller  168  and the communication unit  170  under the irradiated surface  44  to protect the cassette controller  168  and the communication unit  170  against damage which would otherwise be caused if irradiated with the radiation  12 . The battery  166  supplies electric power to the radiation detector  20 , the cassette controller  168 , and the communication unit  170  in the cassette  22 . 
     As shown in  FIG. 8 , the radiation detector  20  comprises a number of pixels  180  arrayed on a substrate, not shown, a number of gate lines  182  for supplying control signals to the pixels  180 , and a number of signal lines  184  for reading electric signals output from the pixels  180 . 
     A circuit arrangement of the radiation detector  20 , which is of the indirect conversion type, for example, that is housed in the cassette  22  will be described in detail below with reference to  FIG. 9 . 
     As shown in  FIG. 9 , the radiation detector  20  comprises an array of thin-film transistors (TFTs)  188  arranged in rows and columns and a photoelectric conversion layer  186  including the pixels  180  and made of a material such as amorphous silicon (a-Si) or the like for converting visible light into electric signals, the photoelectric conversion layer  186  being disposed on the array of TFTs  188 . When the radiation  12  is applied to the radiation detector  20 , the pixels  180  generate electric charges by converting visible light into analog electric signals. Then, when the TFTs  188  are turned on along each row at a time, the electric charges are read from the pixels  180  as an image signal. 
     The TFTs  188  are connected to the respective pixels  180 . The gate lines  182  which extend parallel to the rows and the signal lines  184  which extend parallel to the columns are connected to the TFTs  188 . The gate lines  182  are connected to a line scanning driver  190 , and the signal lines  184  are connected to a multiplexer  192 . The gate lines  182  are supplied with control signals Von, Voff for turning on and off the TFTs  188  along the rows from the line scanning driver  190 . The line scanning driver  190  comprises a plurality of switches SW 1  for switching between the gate lines  182  and an address decoder  194  for outputting a selection signal for selecting one of the switches SW 1  at a time. The address decoder  194  is supplied with an address signal from the cassette controller  168 . 
     The signal lines  184  are supplied with electric charges stored by the pixels  180  through the TFTs  188  arranged in the columns. The electric charges supplied to the signal lines  184  are amplified by amplifiers  196  connected respectively to the signal lines  184 . The amplifiers  196  are connected through respective sample and hold circuits  198  to the multiplexer  192 . The multiplexer  192  comprises a plurality of switches SW 2  for successively switching between the signal lines  184  and an address decoder  200  for outputting a selection signal for selecting one of the switches SW 2  at a time. The address decoder  200  is supplied with an address signal from the cassette controller  168 . The multiplexer  192  has an output terminal connected to an A/D converter  202 . A radiographic image signal generated by the multiplexer  192  based on the electric charges from the sample and hold circuits  198  is converted by the A/D converter  202  into a digital image signal representing radiographic image information, which is supplied to the cassette controller  168 . 
     The TFTs  188  which function as switching devices may be combined with another image capturing device such as a CMOS (Complementary Metal-Oxide Semiconductor) image sensor or the like. Alternatively, the TFTs  188  may be replaced with a CCD (Charge-Coupled Device) image sensor for shifting and transferring electric charges with shift pulses which correspond to gate signals in the TFTs. 
       FIG. 10  shows in block form the radiographic image capturing apparatus  10 , and  FIG. 11  shows in block form the medical organization  40 . 
     Those components of the radiographic image capturing apparatus  10  and the medical organization  40  which have not been described above with reference to  FIGS. 1 through 9  will be described below with reference to  FIGS. 10 and 11 . Some of the components described with reference to  FIGS. 1 through 9  will also be described in specific detail below with reference to  FIGS. 10 and 11 . 
     The cassette controller  168  of the cassette  22  comprises an image memory  210 , an address signal generator  212 , and a cassette ID memory  214 . 
     The address signal generator  212  supplies address signals to the address decoder  194  of the line scanning driver  190  and the address decoder  200  of the multiplexer  192 . The image memory  210  stores radiographic image information detected by the radiation detector  20 . The cassette ID memory  214  stores cassette ID information for identifying the radiographic image capturing apparatus  10  or specifically, the cassette  22  thereof. 
     The cassette controller  168  sends the cassette ID information stored in the cassette ID memory  214  and the radiographic image information stored in the image memory  210  from the communication unit  170  to the mobile information terminal  34  via the USB terminal  172  and the USB cable  26 . 
     The mobile information terminal  34  includes: a communication unit (controller communication unit, camera image communication unit)  218  which is capable of sending signals to and receiving signals from an external circuit via an antenna  216  by way of wireless communications, of sending signals to and receiving signals from external circuits via the USB terminals  84 ,  88 ,  90  by way of wired communications, and of sending signals to and receiving signals from the memory card  92  inserted in the card slot  94 ; a battery  220  for supplying electric power to various components of the mobile information terminal  34 ; a control processor  222  for performing various control sequences; and a memory  224  for storing camera image information, radiographic image information, etc. 
     When the operator  32  turns on the power supply switch  76 , the battery  220  supplies electric power to the web camera  30 , the speakers  78 , the microphone  80 , the communication unit  218 , and the control processor  222 . While the mobile information terminal  34 , the radiation source device  16 , and the cassette  22  are being electrically connected to each other by the USB cables  24 ,  26 , the battery  220  can charge the batteries  134 ,  166  via the USB cables  24 ,  26 . The battery  220  can be charged from an external circuit via the input terminal  96 . 
     The control processor  222  comprises a CPU of the mobile information terminal  34  and carries out various control sequences by reading and executing programs stored in the memory  224 . 
     Specifically, the control processor  222  stores camera image information captured by the web camera  30  and radiographic image information and cassette ID information received from the cassette  22  via the USB cable  26  and the communication unit  218  into the memory  224 , displays a corresponding camera image and/or a corresponding radiographic image on the display unit  64 , and sends the camera image information and/or the radiographic image information and the cassette ID information to the medical organization  40  via the communication unit  218 , the antenna  216 , and the network  36  by way of wireless communications. The control processor  222  also sends a sound signal representing the voice of the operator  32  or the voice of the subject  18  detected by the microphone  80  to the medical organization  40  via the communication unit  218 , the antenna  216 , and the network  36  by way of wireless communications. 
     The control processor  222  displays, on the display unit  64 , a camera image of the doctor  38  captured by the web camera  116  and received from the medical organization  40  via the network  36 , the antenna  216 , and the communication unit  218 , and outputs the voice of the doctor  38  from the speakers  78  based on a sound signal received from the medical organization  40 . When the control processor  222  receives an exposure control signal from the medical organization  40 , the control processor  222  generates a synchronization control signal depending on the received exposure control signal and sends the generated synchronization control signal to the radiation source device  16  and the cassette  22  via the USB cables  24 ,  26  thereby to synchronize the outputting of the radiation  12  from the radiation source  14  and the detection and conversion of the radiation  12  into the radiation image information by the radiation detector  20 . 
     The console  106  also includes a memory  228  and a control processor  226  for performing various control sequences. 
     The control processor  226  comprises a CPU of the main body  108  and carries out various control sequences by reading out and executing programs stored in the memory  228 . 
     Specifically, the control processor  226  stores camera image information captured by the web camera  116  into the memory  228 , displays a corresponding camera image on the display unit  112 , and sends the camera image information to the mobile information terminal  34  via the communication unit  104 , the antenna  102 , and the network  36  by way of wireless communications. The control processor  226  also sends a sound signal representing the voice of the doctor  38  detected by the microphone  122  to the mobile information terminal  34  via the communication unit  104 , the antenna  102 , and the network  36  by way of wireless communications. 
     The control processor  226  stores camera image information sent from the mobile information terminal  34  by way of wireless communications and/or radiographic image information and cassette ID information into the memory  228 , and displays a camera image and/or a radiographic image on the display unit  112 . The control processor  226  outputs the voice of the operator  32  or the voice of the subject  18  from the speaker  118  based on a sound signal sent from the mobile information terminal  34  by way of wireless communications. 
     Before the radiation source  14  emits the radiation  12 , i.e., during the preparatory procedure, if a body region of the subject  18  to be imaged is included in the outer frame of the guide lines  46  on a camera image captured by the web camera  30  and displayed on the display unit  112  (see  FIGS. 14A and 14B ), then the doctor  38  judges that an appropriate radiographic image of the body region of the subject  18  to be imaged can be acquired by applying the radiation  12  to the subject  18 , and turns on the exposure switch  120 . When the exposure switch  120  is turned on, the control processor  226  generates an exposure control signal for starting to emit the radiation  12  from the radiation source  14 , and sends the generated exposure control signal to the mobile information terminal  34  via the communication unit  104 , the antenna  102 , and the network  36  by way of wireless communications. 
     However, before the radiation source  14  emits the radiation  12 , if a body region of the subject  18  to be imaged is not included, or only a portion of the body region is included, in the outer frame of the guide lines  46  on a camera image captured by the web camera  30  and displayed on the display unit  112  (see  FIG. 14C ), then the doctor  38  judges that an appropriate radiographic image of the body region of the subject  18  to be imaged cannot be acquired by applying the radiation  12  to the subject  18 . The doctor  38  does not turn on the exposure switch  120 , but gives a voice instruction via the microphone  122  to change the position or attitude of the subject  18  until the body region to be imaged is included in the outer frame of the guide lines  46 . When the control processor  226  receives a sound signal (instruction signal) from the microphone  122  based on the voice of the doctor  38 , the control processor  226  goes not generate an exposure control signal. 
     The radiographic image capturing apparatus  10  and the radiographic image capturing system  11  according to the present embodiment are basically constructed as described above. Operation of the radiographic image capturing apparatus  10  and the radiographic image capturing system  11  to carry out a radiographic image capturing method will be described below with reference to flowcharts shown in  FIGS. 12 and 13 . 
     In step S 1  shown in  FIG. 12 , the operator  32  carries the attaché case  98  from the medical organization  40  where the doctor  38  is unable to see the patient  18  directly to a disaster site or a home receiving home-care services according to the directions from the doctor  38  who has the legal authority about the application of the radiation  12  to the subject  18 . 
     In step S 2  after the operator  32  has arrived at the disaster site or the home, the operator  32  removes the radiation source device  16 , the cassette  22 , the mobile information terminal  34 , and the USB cables  24 ,  26  from the attaché case  98 , connects the mobile information terminal  34  and the radiation source device  16  to each other with the USB cable  24 , and connects the mobile information terminal  34  and the cassette  22  with the USB cable  26 . The mobile information terminal  34  and the radiation source device  16  are electrically connected to each other by the USB cable  24 , and the mobile information terminal  34  and the cassette  22  are electrically connected to each other by the USB cable  26 . In step S 2 , the operator  32  places the mobile information terminal  34 , the radiation source device  16 , and the cassette  22  in the layout shown in  FIGS. 1 through 4 . 
     In step S 3 , the operator  32  turns the lid  66  away from the main body  62  about the shaft  68  and the hinges  70  to unfold the mobile information terminal  34  from the folded form until the operating unit  60  and the display unit  64  can be seen as shown in  FIGS. 1 through 4 . Thereafter, the operator  32  turns on the power supply switch  76  to activate the mobile information terminal  34 . 
     When the power supply switch  76  is turned on, the battery  220  starts to supply electric power to the web camera  30 , the display unit  64 , the microphone  80 , the communication unit  218 , and the control processor  222 , and also starts to charge the battery  134  of the radiation source device  16  and the battery  166  of the cassette  22  from the USB terminals  84 ,  88  via the USB cables  24 ,  26 . When supplied with electric power from the battery  220 , the web camera  30  starts to capture an image of the imaging area  28  and outputs captured image information to the control processor  222  in step S 4 . 
     When supplied with electric power from the battery  220 , the control processor  222  reads out programs from the memory  224  and executes the programs to store the camera image information sent from the web camera  30  into the memory  224 , display a corresponding camera image on the display unit  64 , and sends the camera image information from the communication unit  218  via the antenna  216  to an external circuit by way of wireless communications. 
     The camera image information from the web camera  30  is sent via the network  36  to the medical organization  40  by way of wireless communications. The communication unit  104  of the medical organization  40  outputs the camera image information received via the antenna  102  to the control processor  226 . The control processor  226  stores the camera image information into the memory  228  and displays a corresponding camera image on the display unit  112  by reading out programs stored in the memory  228  and executing the programs. By seeing the camera image displayed on the display unit  112 , the doctor  38  can clearly recognize the positional relationship between the radiation source device  16 , the subject  18 , and the cassette  22  at the disaster site or the home. 
     In step S 5 , the operator  32  performs a preparatory procedure for making the radiographic image capturing apparatus  10  ready to capture a radiographic image of a body region of the subject  18  to be imaged (e.g., the chest of the subject  18 ). 
       FIG. 13  is a flowchart of the preparatory procedure in step S 5 .  FIGS. 14A through 14C  are views showing by way of example images displayed on the display unit  64  of the mobile information terminal  34  and the display unit  112  of the console  106  during the preparatory procedure. 
     In step S 51  shown in  FIG. 13 , the operator  32  operates the operating unit  60  of the mobile information terminal  34  to register image capturing conditions (e.g., a tube voltage and a tube current of the radiation source  14 , an exposure time of the radiation  12 ) including subject information of the subject  18  to be imaged. If a body region to be imaged and an image capturing method are known, then the operator  32  also registers them as image capturing conditions. The control processor  222  stores (registers) the entered image capturing conditions into the memory  224 . 
     If the subject  18  to be imaged is known before the operator  32  goes to the disaster site or the home, then the operator  32  may operate the operating unit  60  of the mobile information terminal  34  at the medical organization  40  to which the operator  32  belongs to register the image capturing conditions. 
     Since the mobile information terminal  34  and the medical organization  40  can send signals to and receive signals from each other via the network  36  by way of wireless communications, as described above, the doctor  38  may operate the operating unit  114  of the console  106  to enter the image capturing conditions and send the entered image capturing conditions via the network  36  to the mobile information terminal  34  by way of wireless communications. Alternatively, the doctor  38  at the medical organization  40  may send image capturing conditions to be registered in the memory  224  via the network  36  by way of wireless communications, and the operator  32  may operate the operating unit  60  to register the image capturing conditions that have been sent from the doctor  38 . 
     In step S 52 , the operator  32  turns on the switch  50  of the cassette  22 . The battery  166  supplies electric power to the radiation detector  20 , the cassette controller  168 , and the communication unit  170 , thereby activating the cassette  22  in its entirety. The cassette controller  168  sends an activation notice signal representing that the cassette  22  has been activated to the mobile information terminal  34  via the communication unit  170 , the USB terminal  172 , and the USB cable  26 . 
     Based on the activation notice signal received via the USB cable  26 , the USB terminal  88 , and the communication unit  218 , the control processor  222  sends an image-capture preparation command signal for image-capture preparations and the image capturing conditions registered in the memory  224  to the radiation source device  16  and the cassette  22  via the communication unit  218 , the USB terminals  84 ,  88 , and the USB cables  24 ,  26 . 
     Since the battery  134  of the radiation source device  16  supplies electric power to the communication unit  136  and the radiation source controller  138  at all times, when the radiation source controller  138  receives the image-capture preparation command signal and the image capturing conditions via the USB cable  24 , the USB terminal  132 , and the communication unit  136 , the radiation source controller  138  registers the image capturing conditions and controls the battery  134  to supply electric power to the irradiated field lamp  56 . When the irradiated field lamp  56  is supplied with the electric power from the battery  134 , the irradiated field lamp  56  emits the irradiation light  54 . The irradiation light  54  is reflected by the mirror  144  to the collimator  146 , and is output from the radiation source device  16  and applied to the irradiated surface  44  of the cassette  22  in step S 53 . 
     If the imaging distance is adjusted to the SID, then the irradiated field that is displayed on the irradiated surface  44  by the application of the irradiation light  54  is substantially in agreement with the outer frame of the guide lines  46 . If the position of the irradiated field, i.e., the range irradiated by the irradiation light  54 , is not in agreement with the position of the outer frame of the guide lines  46  or if the size of the irradiated field is not in agreement with the size of the outer frame of the guide lines  46 , then the operator  32  adjusts the positional relationship between the radiation source device  16  and the cassette  22  in order to equalize the imaging distance with the SID. 
     The image-capture preparation command signal and the image capturing conditions are also sent to the cassette  22  to enable the cassette controller  168  to recognize that the radiographic image capturing apparatus  10  has been readied for capturing radiographic images, and registers the image capturing conditions into the cassette ID memory  214 . It has been described above that the radiation detector  20  is activated when the switch  50  is turned on. However, when the cassette controller  168  receives the image-capture preparation command signal, the battery  166  may supply electric power (bias voltage Vb) to the radiation detector  20  to activate the radiation detector  20 . 
     In step S 54  after the imaging distance is adjusted to the SID to bring the irradiated field into agreement with the outer frame of the guide lines  46 , the operator  32  puts the subject  18  in front of the irradiated surface  44  of the cassette  22  and positions the subject  18  to bring the body region of the subject  18  to be imaged into the outer frame of the guide lines  46 . 
     The web camera  30  captures a camera image of the imaging area  28  which covers the body region of the subject  18  to be imaged, the radiation source device  16 , and the irradiated surface  44  of the cassette  22 , and the display unit  64  of the mobile information terminal  34  displays the camera image captured by the web camera  30 . The operator  32  can position the subject  18  to place the body region to be imaged within the outer frame of the guide lines  46  on the camera image by instructing the subject  18  to move while seeing, i.e., monitoring, the camera image displayed on the display unit  64 . 
     The camera image captured by the web camera  30  is sent, i.e., distributed, from the control processor  222  to the medical organization  40  via the antenna  216  and the network  36 . The communication unit  104  of the medical organization  40  receives the camera image via the antenna  102  and outputs the received camera image to the console  106 . The control processor  226  of the console  106  stores the camera image into the memory  228  and displays the camera image on the display unit  112 . 
     In step S 6  shown in  FIG. 12 , the doctor  38  in the medical organization  40  sees the camera image displayed on the display unit  112  and determines whether the preparatory procedure is completed or not, i.e., whether the body region of the subject  18  to be imaged is included within the outer frame of the guide lines  46  or not. 
     If the camera image displayed on the display units  64 ,  112  shows that the body region (chest) of the subject  18  to be imaged is included within the outer frame of the guide lines  46  as shown in  FIG. 14A , then the doctor  38  judges that it is possible to obtain an appropriate radiographic image of the subject  18  by imaging the subject  18  according to the positional relationship between the body region to be imaged and the guide lines  46  that are presently displayed on the display units  64 ,  112  (step S 6 : YES), and talks into the microphone  122  or operates the operating unit  114  to indicate that the preparatory procedure is completed. 
     The control processor  226  of the console  106  sends a signal based on the voice detected by the microphone  122  or the input applied to the operating unit  114  to the mobile information terminal  34  via the communication unit  104 , the antenna  102 , and the network  36  by way of wireless communications. Based on the signal received via the antenna  216  and the communication unit  218 , the control processor  222  of the mobile information terminal  34  displays a visual message “OK” indicating that the preparatory procedure is completed on the display unit  64 , as shown in  FIG. 14A , or outputs a sound message “OK” from the speakers  78 . Therefore, the operator  32  knows that the preparatory procedure is completed by seeing the visual message “OK” displayed on the display unit  64  or hearing the sound message “OK” from the speakers  78 . 
     The web camera  116  of the console  106  captures a camera image of the doctor  38 , and the control processor  226  sends the camera image captured by the web camera  116  to the mobile information terminal  34  via the communication unit  104 , the antenna  102 , and the network  36 . The control processor  222  may display both the camera image captured by the web camera  30 , i.e., an image indicating the positioning of the subject  18 , and the camera image captured by the web camera  116 , i.e., an image of the doctor  38 , on the display unit  64 , with the visual message “OK” being displayed over the camera image captured by the web camera  116 , as shown in  FIG. 14B . 
     Since the image of the doctor  38  is displayed on the display unit  64 , the operator  32  can see the image displayed on the display unit  64  and immediately understand that the doctor  38  has confirmed the camera image captured by the web camera  30  and has approved of image capturing at the present position of the subject  18 , i.e., has indicated the completion of the preparatory procedure. 
     In addition to the displayed image shown in  FIG. 14A  or  14 B, the voice of the doctor  38  which is detected by the microphone  122  may be output from the speakers  78 . Furthermore, the display unit  112  may display the same image as the image displayed on the display unit  64  as shown in  FIG. 14A  or  14 B. 
     If the body region of the subject  18  to be imaged is not included, or only a portion of the body region is included, in the outer frame of the guide lines  46  on the camera image captured by the web camera  30  and displayed on the display unit  112  (see  FIG. 14C ) in step S 6 , then the doctor  38  judges that a desired radiographic image of the subject  18  cannot be acquired by imaging the subject  18  according to the positional relationship between the body region to be imaged and the guide lines  46  that are presently displayed on the display units  64 ,  112  (step S 6 : NO), and talks into the microphone  122  or operates the operating unit  114  to indicate to the operator  32  that the present positional relationship between the body region to be imaged and the guide lines  46  is inappropriate and the preparatory procedure is to be performed again. 
     The control processor  226  of the console  106  sends a command signal based on the voice detected by the microphone  122  or the input applied to the operating unit  114  to the mobile information terminal  34  via the communication unit  104 , the antenna  102 , and the network  36  by way of wireless communications. Based on the command signal received via the antenna  216  and the communication unit  218 , the control processor  222  of the mobile information terminal  34  displays a visual message “MOVE PATIENT TO CASSETTE”, or the like, indicating that the preparatory procedure is to be performed again on the display unit  64 , as shown in  FIG. 14C , or outputs a corresponding sound message from the speakers  78 . Therefore, the operator  32  immediately understands that the operator  32  is instructed to perform the preparatory procedure again by seeing the visual message displayed on the display unit  64  or hearing the sound message from the speakers  78 , and positions the subject  18  again according to the visual message or the sound message. 
     When the preparatory procedure in step S 5  is to be performed again, since the processing in steps S 51  through S 53  has already been carried out, the operator  32  only positions the subject  18  in step S 54 . 
     In step S 7 , providing the preparatory procedure is completed (step S 6 : YES), the doctor  38  turns on the exposure switch  120 . The control processor  226  generates an exposure control signal for starting to emit the radiation  12  from the radiation source  14 , and sends the generated exposure control signal to the mobile information terminal  34  via the communication unit  104 , the antenna  102 , and the network  36  by way of wireless communications. 
     When the control processor  222  receives the exposure control signal via the antenna  216  and the communication unit  218 , the control processor  222  generates a synchronization control signal to synchronize the outputting from the radiation source  14  and the detection and conversion of the radiation  12  by the radiation detector  20  into the radiation image information for thereby capturing a radiographic image of the subject  18 , and sends the generated synchronization control signal to the radiation source device  16  and the cassette  22  via the communication unit  218 , the USB terminals  84 ,  88 , and the USB cables  24 ,  26 . 
     In step S 8 , when the radiation source controller  138  receives the synchronization control signal via the USB terminal  132  and the communication unit  136 , the radiation source controller  138  stops supplying the electric power from the battery  134  to the irradiated field lamp  56 , thereby stopping the application of the irradiation light  54  from the irradiated field lamp  56 , and controls the radiation source  14  to applying a radiation  12  of a predetermined dose to the subject  18  according to the image capturing conditions registered in the radiation source controller  138 . 
     In the radiation source  14 , the rotating mechanism  148  is controlled by the radiation source controller  138  to rotate the rotational shaft  150  and the rotary anode  152 . The power supply  142  applies a negative voltage to the field-emission-type electron source  158  based on the electric power supplied from the battery  134 , and the power supply  140  applies a voltage between the rotary anode  152  and the cathode  156  based on the electric power supplied from the battery  134 . The field-emission-type electron source  158  emits electrons which are accelerated by the voltage applied between the rotary anode  152  and the cathode  156  and bombard the target layer  154 . The surface of the target layer  154  which is bombarded with the electrons emits from the focused point  160  the radiation  12  whose intensity depends on the applied electrons. 
     The radiation  12  passes through the mirror  144  and is constricted in its irradiation area by the collimator  146  and output from the radiation source device  16  and applied to the subject  18 . The radiation  12  is applied to and passes through the subject  18  for a given irradiation time depending on the image capturing conditions, and reaches the radiation detector  20  in the cassette  22 . 
     In step S 9 , since the radiation detector  20  is of the indirect conversion type, the scintillator of the radiation detector  20  emits visible light having an intensity depending on the intensity of the radiation  12 , and the pixels  180  of the photoelectric conversion layer  186  converts the visible light into electric charges and store the electric charges. The electric charges stored by the pixels  180 , which are representative of a radiographic image of the subject  18 , are read from the pixels  180  according to address signals which are supplied from the address signal generator  212  of the cassette controller  168  to the line scanning driver  190  and the multiplexer  192 . 
     Specifically, in response to the address signal supplied from the address signal generator  212 , the address decoder  194  of the line scanning driver  190  outputs a selection signal to select one of the switches SW 1 , which supplies the control signal Von to the gates of the TFTs  188  connected to the gate line  182  corresponding to the selected switch SW 1 . In response to the address signal supplied from the address signal generator  212 , the address decoder  200  of the multiplexer  192  outputs a selection signal to successively turn on the switches SW 2  to switch between the signal lines  184  for thereby reading out the electric charges stored in the pixels  180  connected to the selected gate line  182 , through the signal lines  184 . 
     The electric charges read out from the pixels  180  connected to the selected gate line  182  are amplified by the respective amplifiers  196 , sampled by the sample and hold circuits  198 , and supplied to the multiplexer  192 . Based on the supplied electric charges, the multiplexer  192  generates and supplies a radiographic image signal to the A/D converter  202 , which converts the radiographic image signal into a digital signal. The digital signal which represents the radiographic image information is temporally stored in the image memory  210  of the cassette controller  168  in step S 10 . 
     Similarly, the address decoder  194  of the line scanning driver  190  successively turns on the switches SW 1  to switch between the gate lines  182  according to the address signal supplied from the address signal generator  212 . The electric charges stored in the pixels  180  connected to the successively selected gate lines  182  are read through the signal lines  184 , and processed by the multiplexer  192  and the A/D converter  202  into a digital signal, which is stored in the image memory  210  of the cassette controller  168  in step S 10 . 
     The radiographic image information represented by the digital signal stored in the image memory  210  is transmitted together with the cassette ID information stored in the cassette ID memory  214  to the mobile information terminal  34  via the communication unit  170 , the USB terminal  172 , and the USB cable  26  by way of wired communications. The control processor  222  of the mobile information terminal  34  stores the radiographic image information and the cassette ID information received via the USB terminal  88  and the communication unit  218  into the memory  224 , and displays a corresponding radiographic image on the display unit  64  in step S 11  (see  FIG. 15A ). 
     The control processor  222  also sends the radiographic image information and the cassette ID information to the medical organization  40  via the communication unit  218 , the antenna  216 , and the network  36  by way of wireless communications. In the medical organization  40 , the communication unit  104  outputs the radiographic image information and the cassette ID information received via the antenna  102  to the control processor  226 . The control processor  226  stores the radiographic image information and the cassette ID information into the memory  228 , and displays a corresponding radiographic image on the display unit  112  (see  FIG. 15A ). 
     In step S 12 , the doctor  38  sees the radiographic image of the subject  18  displayed on the display unit  112  and determines whether the displayed radiographic image is appropriate or not. 
     For example, if the radiographic image displayed on the display units  64 ,  112  includes the body region (chest) of the subject  18  to be imaged as shown in  FIG. 15A , then the doctor  38  judges that the process of capturing a radiographic image of the body region to be imaged is completed (step S 21 : YES), and talks into the microphone  122  or operates the operating unit  114  to indicate to the operator  32  that the image capturing process is completed. 
     The control processor  226  of the console  106  sends a signal based on the voice detected by the microphone  122  or the input applied to the operating unit  114  to the mobile information terminal  34  via the communication unit  104 , the antenna  102 , and the network  36  by way of wireless communications. Based on the signal received via the antenna  216  and the communication unit  218 , the control processor  222  of the mobile information terminal  34  displays a visual message “IMAGE CAPTURING PROCESS IS COMPLETED” indicating that the image capturing process is completed on the display unit  64 , as shown in  FIG. 15A , or outputs a corresponding sound message from the speakers  78 . Therefore, the operator  32  knows that the image capturing process is completed by seeing the visual message displayed on the display unit  64  or hearing the sound message from the speakers  78 . 
     The control processor  222  may display both the radiographic image and the camera image captured by the web camera  116 , i.e., an image of the doctor  38 , on the display unit  64 , with the visual message “IMAGE CAPTURING PROCESS IS COMPLETED” being displayed over the camera image captured by the web camera  116 , as shown in  FIG. 15B , as in the case shown in  FIG. 14B . 
     Since the image of the doctor  38  is displayed along with the image on the display unit  64 , the operator  32  can immediately understand that the doctor  38  has indicated the completion of the image capturing process. 
     In addition to the displayed image shown in  FIG. 15A  or  15 B, the voice of the doctor  38  which is detected by the microphone  122  may be output from the speakers  78 . Furthermore, the display unit  112  may display the same image as the image displayed on the display unit  64  as shown in  FIG. 15A  or  15 B. 
     If the body region of the subject  18  to be imaged is not included, or only a portion of the body region is included, in the radiographic image displayed on the display unit  112  (see  FIG. 15C ) in step S 12 , then the doctor  38  judges that an appropriate radiographic image has not been acquired and the image capturing process needs to be performed again (step S 12 : NO), and talks into the microphone  122  or operates the operating unit  114  to indicate to the operator  32  that the image capturing process is to be performed again. 
     The control processor  226  of the console  106  sends a signal based on the voice detected by the microphone  122  or the input applied to the operating unit  114  to the mobile information terminal  34  via the communication unit  104 , the antenna  102 , and the network  36  by way of wireless communications. Based on the signal received via the antenna  216  and the communication unit  218 , the control processor  222  of the mobile information terminal  34  displays a visual message “IMAGE CAPTURE FAILURE, PERFORM IMAGE CAPTURING PROCESS AGAIN” indicating that the image capturing process is to be performed again on the display unit  64 , as shown in  FIG. 15C , or outputs a corresponding sound message from the speakers  78 . Therefore, the operator  32  recognizes that the image capturing process is to be performed again by seeing the visual message displayed on the display unit  64  or hearing the sound message from the speakers  78 , and performs the preparatory procedure again according to instructions in step S 5 . 
     In step S 13  after the image capturing process completed, the operator  32  operates the operating unit  60  or presses the power supply switch  76  to shut down the mobile information terminal  34 . The battery  220  stops supplying electric power to various components of the mobile information terminal  34 , and also stops charging the batteries  134 ,  166  via the USB cables  24 ,  26 . The radiation source controller  138  detects when the battery  134  stops being charged, and causes the battery  134  from supplying electric power to various components of the radiation source device  16 . The operator  32  also presses the switch  50  to shut down the cassette  22 . The battery  166  now stops supplying electric power to various components of the cassette  22 . 
     Then, the operator  32  turns the lid  66  toward the main body  62  about the shaft  68  and the hinges  70  until the teeth  72  fit into the recesses  74  when the mobile information terminal  34  is folded. The operator  32  detaches the USB cables  24 ,  26  from the radiation source device  16 , the cassette  22 , and the mobile information terminal  34 , electrically disconnecting the mobile information terminal  34  from the radiation source device  16  and also electrically disconnecting the mobile information terminal  34  from the cassette  22 . Thereafter, the operator  32  places the radiation source device  16 , the cassette  22 , the mobile information terminal  34 , and the USB cables  24 ,  26  into the attaché case  98  in step S 14 . The operator  32  then brings the attaché case  98  back to the medical organization  40  to which the operator  32  belongs. 
     In the medical organization  40 , the radiographic image information stored in the memory  224  of the radiographic image capturing apparatus  10  which the operator  32  has brought back is sent to the RIS of an in-hospital network or the console  106  via the communication unit  218  and the antenna  216  by way of wireless communications or via the USB terminals  84 ,  88 ,  90  by way of wired communications. Alternatively, the radiographic image information stored in the memory  224  of the radiographic image capturing apparatus  10  is saved in the memory card  92 , which is then removed from the card slot  94  and connected to the RIS or the console  106 . The medical organization  40  is now able to analyze the radiographic image information in detail for interpretation and diagnosis. 
     As described above, since the mobile information terminal  34  sends the radiographic image information, etc. via the network  36  to the medical organization  40  while the radiographic image capturing apparatus  10  is placed at the disaster site or the home, the medical organization  40  may analyze the transmitted radiographic image information in detail for interpretation and diagnosis. 
     With the radiographic image capturing apparatus  10 , the radiographic image capturing system  11 , and the radiographic image capturing method according to the present embodiment, as described above, the web camera  30  captures a camera image of at least the cassette  22 , i.e., the guide lines  46  corresponding to the radiation detector  20  housed in the cassette  22  at the disaster site or the home, and the communication unit  218  sends the camera image captured by the web camera  30  via the network  36  to the communication unit  104  of the medical organization  40 . 
     Based on the camera image received by the communication unit  104 , the doctor (or the radiological technician)  38  waiting in the remote medical organization  40  where the doctor  38  is unable to see the subject  18  directly can instruct the operator  32  at the disaster site or the home to capture a radiographic image of the subject  18  in real time. Consequently, it is possible to capture a radiographic image of the subject  18  even though the doctor  38  does not directly go to the disaster site or the home, or in other words, even though the doctor  38  does not accompany the operator  32  who is not a qualified medical radiological technician, i.e., who does not have the legal authority about the application of the radiation  12  to the subject  18 . 
     The outer frame of the guide lines  46  is aligned with the irradiated field which is irradiated with the radiation  12  at the time the imaging distance is set to the SID, and the web camera  30  captures a camera image of the outer frame of the guide lines  46 . The doctor  38  confirms the camera image captured by the web camera  30 , and if the body region of the subject  18  to be imaged is included in the outer frame of the guide lines  46 , i.e., if the body region of the subject  18  to be imaged is displayed inwardly of the outer frame of the guide lines  46 , the doctor  38  can judge that an appropriate radiographic image of the subject  18  can be acquired by applying the radiation  12  to the subject  18  thus positioned. If the body region of the subject  18  to be imaged is not included in the outer frame of the guide lines  46  or only a portion of the body region of the subject  18  to be imaged is included in the outer frame of the guide lines  46 , then the doctor  38  can judge that an appropriate radiographic image of the subject  18  cannot be acquired by applying the radiation  12  to the subject  18  thus positioned. 
     As described above, the web camera  30  captures a camera image of the guide lines  46 , and the doctor  38  sees, i.e., monitors, the camera image captured by the web camera  30  to determine whether the body region of the subject  18  to be imaged is included in the outer frame of the guide lines  46  or not and hence to determine whether an appropriate radiographic image of the subject  18  can be acquired or not. As a result, even if the doctor  38  is unable to see the subject  18  and the operator  32  directly, the doctor  38  is able to appropriately instruct the operator  32  at the site to perform the preparatory procedure. 
     The web camera  30  is disposed on the upper surface of the lid  66  of the mobile information terminal  34  and integrally combined with the mobile information terminal  34 . As the web camera  30  captures a camera image of the radiation source device  16 , the subject  18 , and the cassette  22  including the guide lines  46  in the layout shown in  FIGS. 1 through 4 , it is possible to reliably obtain a camera image including the guide lines  46 . 
     The operator  32  gives directions to the subject  18  while operating the mobile information terminal  34  to position the subject  18  with respect to the guide lines  46 . Therefore, even if the radiation source  14  applies the radiation  12  to the subject  18  while the operator  32  is operating the mobile information terminal  34 , the operator  32  is reliably prevented from being exposed to the radiation  12 . 
     The communication unit  218  of the mobile information terminal  34  which incorporates the web camera  30  sends the camera image captured by the web camera  30  to the medical organization  40  via the antenna  216  and the network  36 . Accordingly, the camera image captured by the web camera  30  is reliably sent to the medical organization  40 . 
     The control processor  222  of the mobile information terminal  34  generates a synchronization control signal to synchronize the outputting of the radiation  12  from the radiation source  14  and the conversion by the radiation detector  20  from the radiation  12  into the radiation image information, and the communication unit  218  sends the synchronization control signal to the communication unit  136  of the radiation source device  16  and the communication unit  170  of the cassette  22 . Consequently, the radiation source  14  and the radiation detector  20  are reliably synchronized in time with each other at the time a radiographic image of the subject  18  is captured. 
     The mobile information terminal  34 , the radiation source device  16 , and the cassette  22  are electrically connected to each other by the USB cables  24 ,  26 . Therefore, the battery  220  of the mobile information terminal  34  can reliably charge the battery  134  of the radiation source device  16  and the battery  166  of the cassette  22 , and signals can reliably be sent and received between the mobile information terminal  34 , the radiation source device  16 , and the cassette  22 . Specifically, the mobile information terminal  34  can reliably send the synchronization control signal and the image capturing conditions to the radiation source device  16  and the cassette  22 , and the cassette  22  can reliably send the radiation image information to the mobile information terminal  34 . 
     Moreover, inasmuch as the camera image captured by the web camera  30  and the radiation image information are sent from the mobile information terminal  34  via the network  36  to the medical organization  40  by way of wireless communications, the doctor  38  in the medical organization  40  can give appropriate directions to the operator  32  and the subject  18  at the site by seeing the camera image and the radiographic image that are displayed on the display unit  112  of the console  106 . 
     The console  106  has the exposure switch  120  for controlling the radiation source  14  to start to emit the radiation  12 . When the doctor  38  turns on the exposure switch  120  based on the camera image displayed on the display unit  112 , the control processor  226  of the console  106  generates an exposure control signal for starting to emit the radiation  12  from the radiation source  14 , and sends the generated exposure control signal to the mobile information terminal  34  via the communication unit  104  and the network  36 . The control processor  222  of the mobile information terminal  34  generates a synchronization control signal depending on the exposure control signal received by the communication unit  218  and sends the generated synchronization control signal to the radiation source device  16  and the cassette  22 . 
     Consequently, the doctor  38  can perform the image capturing process in the medical organization  40  where the doctor  38  cannot see the subject  18  directly in real time while monitoring the subject  18 , without going to the disaster site or the home receiving home-care services. 
     Specifically, when the preparatory procedure is completed, if the body region of the subject  18  to be imaged is included in the outer frame of the guide lines  46  on the camera image captured by the web camera  30 , then the doctor  38  turns on the exposure switch  120  to start capturing a radiographic image of the subject  18 . If the body region of the subject  18  to be imaged is not included, or only a portion of the body region to be imaged is included, in the outer frame of the guide lines  46  on the camera image captured by the web camera  30 , the doctor  38  does not turn on the exposure switch  120 , and instructs the operator  32  to perform the preparatory procedure again. 
     Accordingly, the image capturing process can simply and reliably be performed under remote control from the medical organization  40 . 
     As the doctor  38  directs the operator  32  at the site with visual messages displayed on the display unit  64  and voices output from the speakers  78 , the directions can accurately and efficiently be transmitted from the doctor  38  to the operator  32  at the site. 
     If the camera image output from the web camera  30  comprises a moving image or still images captured intermittently at given time intervals, then the doctor  38  can send timely directions to the operator  32  at the site. If the camera image output from the web camera  30  comprises, a still image captured at a certain time in the preparatory procedure, then the doctor  38  can determine whether the subject  18  is in a position suitable for capturing a radiographic image thereof or not. 
     As the web camera  30  is an optical camera, it can produce a camera image which can easily be seen by the doctor  38  when displayed. 
     It has been described above that the directions of the doctor  38  are transmitted to the operator  32  by both the visual message displayed on the display unit  64  and the sound message output from the speakers  78 . However, the directions of the doctor  38  may be transmitted to the operator  32  by either the visual message displayed on the display unit  64  or the sound message output from the speakers  78 . 
     It has also been described above that the doctor  38  gives the directions to the operator  32  and the operator  32  positions the subject  18  according to the directions. However, since the subject  18  also hears the sound message output from the speakers  78 , the doctor  38  may directly transmit the directions to the subject  18  to position the subject  18 . Alternatively, before the subject  18  positions itself, the subject  18  may confirm the visual message displayed on the display unit  64  and then position itself with respect to the guide lines  46  as per the directions. 
     It has further been described above that the mobile information terminal  34  sends a synchronization control signal via the USB cables  24 ,  26  to the radiation source device  16  and the cassette  22 . However, the control processor  226  of the console  106  may generate a synchronization control signal and send the generated synchronization control signal via the network  36 , the mobile information terminal  34 , and the USB cables  24 ,  26  to the radiation source device  16  and the cassette  22 . 
     Moreover, instead of activating the cassette  22  by turning on the switch  50 , the operator  32  may operate the operating unit  60  or the doctor  38  may operate the operating unit  114  to activate the cassette  22 . 
     It has been described above that the battery  220  charges the batteries  134 ,  166  while the mobile information terminal  34  is electrically connected to the radiation source device  16  and the cassette  22  by the USB cables  24 ,  26 . However, the batteries  134 ,  166  may be charged to a level high enough to capture at least a desired number of radiographic images of the subject  18 . Therefore, the desired number of radiographic images of the subject  18  can reliably be captured in the image capturing process. 
     Alternatively, the batteries  134 ,  166  may be charged only in a period of time from step S 3  through step S 7  shown in  FIG. 12 . According to this alternative, as the batteries  134 ,  166  are not charged when a radiographic image is captured and corresponding radiographic image information is transmitted, the electric charges generated by the pixels  180  are prevented from suffering noises caused by battery charging when a radiographic image of the subject  18  is captured or the radiographic image information is prevented from suffering noises caused by battery charging when the radiographic image information is transmitted. 
     In the above description, the image capturing process is initiated when the exposure switch  120  is turned on. However, inasmuch as the image capturing process may be started according to directions from the doctor  38 , an exposure button (exposure switch) may be displayed on a touch-panel screen of the display unit  112  and may be touched by the doctor  38  to start the image capturing process, or one of the buttons of the operating unit  114  may be pressed dedicated to functioning as an exposure switch and the doctor  38  presses the button to start the image capturing process. 
     The cassette  22  is illustrated as having a rectangular housing shape. However, the cassette  22  may be in the form of a flexible sheet in a portion thereof which includes the radiation detector  20 . The cassette  22  in the form of a flexible sheet makes it possible to reduce the entire radiographic image capturing apparatus  10  in size and weight because the flexible sheet can be coiled into a roll. 
     During the image capturing process, the radiation source device  16  and the cassette  22  are securely fixed in position by holders, not shown. However, the operator  32  may hold the radiation source device  16  by hand at least during the image capturing process. 
     In the above description, the battery  220  charges the batteries  134 ,  166 . However, one of the three batteries may be regarded as a power supply for the entire radiographic image capturing apparatus  10 , and may charge the other two batteries. 
     It has been described above that the camera image captured by the web camera  30  is sent from the communication unit  218  of the mobile information terminal  34  via the network  36  to the communication unit  104  of the medical organization  40 . However, the present embodiment is not limited to such an arrangement. 
     The communication unit  136  of the radiation source device  16  and the communication unit  170  of the cassette  22  may have a function to communicate with the communication unit  104  via the network  36 , and may send the camera image. 
     If the communication units  136 ,  170  have such communication capability, then the communication unit  170  is able to send the radiation image information directly to the communication unit  104  via the network  36  or to send the radiation image information to the communication unit  104  via the communication unit  136  and the network  36 . 
     It is also possible to send and receive all signals between the radiographic image capturing apparatus  10  and the medical organization  40 , between the communication unit  136  and the communication unit  104  or between the communication unit  170  and the communication unit  104 . 
     In the above description, signals are sent and received between the radiographic image capturing apparatus  10  and the medical organization  40  via the network  36  by way of wireless communications. The present embodiment is not limited to such an arrangement, but signals may be sent and received by way of other forms of communications. 
     For example, signals are sent and received between the radiographic image capturing apparatus  10  and the medical organization  40  via the network  36  by way of wired communications. Specifically, if the network  36  includes a repeater (a repeating device), then signals may be sent and received by way of wired communications (or wireless communications) up to the repeater, and may be sent and received by way of wireless communications (or wired communications) beyond the repeater. 
     Another mobile terminal such as a mobile phone or the like may be electrically connected to the mobile information terminal  34 , and may send signals to and receive signals from the medical organization  40  or to and from the radiation source device  16  and the cassette  22  using the communication function of the other mobile terminal. In this case, the communication unit of the other mobile terminal functions as the communication unit  218 . 
     The present embodiment is applicable to the acquisition of radiographic images using a light readout type radiation detector. The light readout type radiation detector operates as follows: When a radiation is applied to a matrix of solid-state detecting devices, the solid-state detecting devices store an electrostatic latent image depending on the dose of the applied radiation. For reading out the stored electrostatic latent image, reading light is applied to the solid-state detecting devices to cause the solid-state detecting devices to generate an electric current representing radiation image information. When erasing light is applied to the radiation detector, radiographic image information representing a residual electrostatic latent image is erased from the radiation detector, which can thus be reused (see Japanese Laid-Open Patent Publication No. 2000-105297). 
     To prevent the radiographic image capturing apparatus  10  from being contaminated with blood and bacteria, the entire radiographic image capturing apparatus  10  may be of a water-resistant and hermetically sealed structure, and may be sterilized and cleaned when necessary so that it can be used repeatedly. 
     In the present embodiment, as shown in  FIG. 16 , a cradle  230  for charging the batteries  134 ,  166 ,  220  (see  FIG. 10 ) is positioned at a desired location in the medical organization  40 . 
     The cradle  230  is electrically connected to the mobile information terminal  34  by a USB cable  234  having connectors  236 ,  238 , electrically connected to the radiation source device  16  by the USB cable  24 , and electrically connected to the cassette  22  by the USB cable  26 . 
     The cradle  230  may not only be able to charge the batteries  134 ,  166 ,  220 , but also have a wireless or wired communication function to send and receive necessary information to and from the console  106  and the RIS of the medical organization  40 . The information that is sent from the cradle  230  may include radiation image information recorded in the radiographic image capturing apparatus  10  that is connected to the cradle  230 . 
     The cradle  230  has a display unit  232  for displaying the charged state of the radiographic image capturing apparatus  10  connected to the cradle  230  and necessary information including radiographic image information acquired from the radiographic image capturing apparatus  10 . 
     A plurality of cradles  230  may be connected to a network, and charged states of radiographic image capturing apparatus  10  that are connected to the cradles  230  may be retrieved through the network, so that the user can confirm the locations of any radiographic image capturing apparatus  10  which are sufficiently charged, based on the retrieved charged states. 
     The radiographic image capturing apparatus  10  according to the present embodiment has been illustrated as being used to capture radiographic images at disaster sites and homes receiving home-care services. However, the radiographic image capturing apparatus  10  according to the present embodiment is not limited to the capture of radiographic images at disaster sites and homes receiving home-care services, but may be mounted on medical examination cars for capturing radiographic images for use in medical examinations or may be used doctor&#39;s rounds in the medical organization  40 . Furthermore, the radiographic image capturing apparatus  10  according to the present embodiment is not limited to use in the capture of radiographic images in the medical field, but is also applicable to the capture of radiographic images in various nondestructive tests, for example. 
     Modifications ranging from first through eleventh modifications of the above embodiment will be described below with reference to  FIGS. 17 through 37B . 
     Those parts of the modifications which are identical to those of the radiographic image capturing apparatus  10  shown in  FIGS. 1 through 16  are denoted by identical reference characters, and will not be described in detail below. In  FIGS. 17 through 37B , the network  36  and the medical organization  40  are omitted from illustration. 
     As shown in  FIG. 17 , a radiographic image capturing apparatus  10 A and a radiographic image capturing system  11 A according to a first modification are different from the radiographic image capturing apparatus  10  and the radiographic image capturing system  11  shown in  FIGS. 1 through 16  in that signals are sent and received between the mobile information terminal  34 , the radiation source device  16 , and the cassette  22  by way of wireless communications. 
     The mobile information terminal  34 , the radiation source device  16 , and the cassette  22  are wirelessly connected to each other within one link. Therefore, no cables are required to send and receive signals between them, and hence no obstacles are present to the operator  32  working on the radiographic image capturing apparatus  10 . The operator  32  is thus able to work efficiently on the radiographic image capturing apparatus  10 A. In addition, as no cables are required, the number of parts of the radiographic image capturing apparatus  10 A is reduced, making it easy to assemble the radiographic image capturing apparatus  10 A on site. 
     Furthermore, as the mobile information terminal  34 , the radiation source device  16 , and the cassette  22  are present within one link, either one of the communication units  136 ,  170 ,  218  (see  FIG. 10 ) may be used to send and receive signals representative of camera images and radiographic images to and from the communication unit  104  of the medical organization  40  (see  FIG. 1 ). 
     According to the first modification, signals may be sent and received by way of optical wireless communications using infrared radiation or the like. 
     As shown in  FIG. 18 , a radiographic image capturing apparatus  10 B and a radiographic image capturing system  11 B according to a second modification are different from the radiographic image capturing apparatus and the radiographic image capturing systems shown in  FIGS. 1 through 17  in that the web camera  30  is incorporated in the radiation source device  16  and captures an image having the guide lines  46  serving as the imaging area  28 . 
     Thus, the web camera  30  and the radiation source device  16  are integrally combined in the second modification. The integral structure of the web camera  30  and the radiation source device  16  is not limited to the structure in which the radiation source device  16  has a built-in web camera  30  shown in  FIG. 18 , but may include the structure in which a radiation source device  16  integrally connected to a web camera  30  at least at the time the radiographic image capturing apparatus  10 B is in use. Specifically, the integral structure of the web camera  30  and the radiation source device  16  includes the cases: (1) the web camera  30  and the radiation source device  16  are electrically connected to each other by a cable attached to the radiographic image capturing apparatus  10 B; (2) the web camera  30  and the radiation source device  16  are connected to each other by cables prepared by the operator  32 ; and (3) the web camera  30  and the radiation source device  16  are connected to each other when in use, whereas the web camera  30  and the radiation source device  16  are separable from each other during maintenance or when not in use. 
     Further, in the second modification, since the camera image captured by the web camera  30  displays only the guide lines  46 , the doctor  38  can easily determine whether the body region of the subject  18  to be imaged is included in the outer frame of the guide lines  46  or not. 
     As shown in  FIG. 19 , a radiographic image capturing apparatus  100  and a radiographic image capturing system  11 C according to a third modification are different from the radiographic image capturing apparatus and the radiographic image capturing systems shown in  FIGS. 1 through 18  in that a separately provided web camera  30  is integrally coupled to the mobile information terminal  34  by electrically connecting the web camera  30  to the mobile information terminal  34  using a USB cable  240  having connectors  242 ,  244 . 
     The web camera  30  is supplied with electric power from the battery  220  via the USB cable  240 , and sends a captured camera image to the mobile information terminal  34  via the USB cable  240 . Though the number of parts of the radiographic image capturing apparatus  100  is increase because the separately provided web camera  30  and mobile information terminal  34  are integrally coupled to each other, the radiographic image capturing apparatus  100  offers the same advantages as the radiographic image capturing apparatus  10  described above. 
     As shown in  FIG. 19 , the web camera  30  includes a communication unit  260 . The communication unit  260  may sent signals representing camera images, radiographic image information, etc. to the communication unit  104  of the medical organization  40  via the network  36  (see  FIG. 1 ). 
     As shown in  FIG. 20 , a radiographic image capturing apparatus  10 D and a radiographic image capturing system  11 D according to a fourth modification are different from the radiographic image capturing apparatus and the radiographic image capturing systems shown in  FIGS. 1 through 19  in that a web camera  246  for capturing an image of the operator  32  at the time the operator  32  operates the mobile communication terminal  34  is provided on the lid  66 . 
     The mobile communication terminal  34  sends a camera image of the operator  32  captured by the web camera  246  to the medical organization  40  via the network  36 . The operator  32  asks the doctor  38  for directions while seeing the image of the doctor  38  which is displayed on the display unit  64 , and the doctor  38  gives directions to the operator  32  while seeing the image of the operator  32  which is displayed on the display unit  112 . Therefore, the operator  32  can feel as if the doctor  38  in the medical organization  40  which is remote from the mobile communication terminal  34  is standing by the operator  32 , and the doctor  38  can also feel as if the operator  32  at the site is standing by the doctor  38 . The operator  32  and the doctor  38  thus feel easy in performing the preparatory procedure. 
     As shown in  FIG. 21 , a radiographic image capturing apparatus  10 E and a radiographic image capturing system  11 E according to a fifth modification are different from the radiographic image capturing apparatus and the radiographic image capturing systems shown in  FIGS. 1 through 20  in that the radiation source device  16  is coupled to and integrally combined with the lid  66  of the mobile information terminal  34 . 
     The radiographic image capturing apparatus  10 E thus constructed can easily be assembled and disassembled on site because the USB cable  24  is dispensed with. As the radiation source device  16  and the mobile information terminal  34  are integrally combined with each other, the battery  134 , the communication unit  136 , and the radiation source controller  138  are also dispensed with. Specifically, the battery  220  is shared as the battery of the radiation source device  16 , the control processor  222  is shared as the radiation source controller of the radiation source device  16 , and the communication unit  218  is shared as the communication unit of the radiation source device  16 . The radiation source device  16  is thus simplified, making it possible to reduce the size of the radiographic image capturing apparatus  10 E. 
     Inasmuch as the radiation source device  16  and the mobile information terminal  34  are integrally combined with each other, the operator  32  can simultaneously adjust the position and direction of the radiation source device  16  with respect to the cassette  22  and the subject  18  while seeing the display unit  64  or by changing the position and direction of the mobile information terminal  34  while operating the operating unit  60 . According to the fifth modification, therefore, it is easy to adjust the position and direction of the radiation source device  16  with respect to the cassette  22  and the subject  18 . 
     In  FIG. 21 , the web camera  30  is incorporated in the lid  66 . However, the web camera  30  may be incorporated in the radiation source device  16 . 
     As shown in  FIG. 22 , a radiographic image capturing apparatus  10 F and a radiographic image capturing system  11 F according to a sixth modification are different from the radiographic image capturing apparatus and the radiographic image capturing systems shown in  FIGS. 1 through 21  in that the radiation source  14  comprises a conventional thermionic-emission radiation source and the radiographic image capturing apparatus  10 F includes a high-voltage power supply  252  for energizing a filament of the radiation source  14 . 
     The radiation source  14  and the communication unit  136  are housed in a casing  250  mounted on the upper end of a stand  248 , and the casing  250  is electrically connected to the high-voltage power supply  252  by the USB cable  24 . The high-voltage power supply  252  and the mobile information terminal  34  are electrically connected to each other by a USB cable  254  having connectors  256 ,  258 . The mobile information terminal  34  can control the high-voltage power supply  252  to cause the radiation source  14  to emit the radiation  12 . 
     According to the sixth modification, the radiographic image capturing apparatus  10 F is relatively large in size and has a relatively large number of parts because it includes the conventional thermionic-emission radiation source. However, the radiographic image capturing apparatus  10 F offers the same advantages as those of the radiographic image capturing apparatus  10  shown in  FIGS. 1 through 16 . 
     As shown in  FIG. 22 , the high-voltage power supply  252  includes a communication unit  262  which may send and receive signals representing radiographic images, camera images, etc. to and from the communication unit  104  of the medical organization  40  via the network  36  (see  FIG. 1 ). 
     As shown in  FIG. 23 , a radiographic image capturing apparatus  10 G and a radiographic image capturing system  11 G according to a seventh modification are different from the radiographic image capturing apparatus and the radiographic image capturing systems shown in  FIGS. 1 through 22  in that the mobile information terminal  34  is dispensed with and the web camera  30 , the radiation source device  16 , and the cassette  22  are separately provided and make up the radiographic image capturing apparatus  10 G and send signals to and receive signals from each other by way of wireless communications. 
     Since the radiation source device  16 , the cassette  22 , and the web camera  30  are wirelessly connected to each other within one link, either one of the communication units  136 ,  170  (see  FIG. 10 ) and the communication unit  260  of the web camera  30  may be used to send and receive signals representative of camera images and radiographic images to and from the communication unit  104  of the medical organization  40  (see  FIG. 1 ). For example, the web camera  30  may send a camera image from the communication unit  260  directly to the medical organization  40  via the network  36  (see  FIG. 1 ), or may send a camera image from the communication unit  260  indirectly to the medical organization  40  via the communication unit  136  of the radiation source device  16  or the communication unit  170  of the cassette  22 . 
     The synchronization control signal is generated by the radiation source controller  138  of the radiation source device  16  or the cassette controller  168  of the cassette  22 , or is supplied from the console  106  via the communication unit  104 , the antenna  102 , and the network  36 . 
     The doctor  38  is able to see the camera image captured by the web camera  30 . If the speakers  78  and the microphone  80  are incorporated in the web camera  30 , the radiation source device  16 , or the cassette  22 , then the operator  32  may ask the doctor  38  for directions about the capture of radiographic images, and the doctor  38  may give directions to the operator  32 . According to the seventh modification, since the display unit  64  is dispensed with, the operator  32  performs the preparatory procedure and other processes according to directions given from the doctor  38  based on sound messages output from the speakers  78 . 
     As shown in  FIG. 24 , a radiographic image capturing apparatus  10 H and a radiographic image capturing system  11 H according to an eighth, modification are different from the radiographic image capturing apparatus  10 G and the radiographic image capturing system  11 G shown in  FIG. 23  in that the web camera  30  is incorporated in the radiation source device  16 . 
     As with the second modification shown in  FIG. 18 , the web camera  30  incorporated in the radiation source device  16  captures an image having the guide lines  46  serving as the imaging area  28 . 
     According to the eighth modification, since the radiation source device  16  and the cassette  22  are wirelessly connected to each other within one link, either one of the communication units  136 ,  170  (see  FIG. 10 ) may be used to send and receive signals representative of camera images and radiographic images to and from the communication unit  104  of the medical organization  40  (see  FIG. 1 ). For example, the web camera  30  may send a camera image from the communication unit  136  directly to the medical organization  40  via the network  36 , or may send a camera image from the communication unit  136  indirectly to the medical organization  40  via the communication unit  170  of the cassette  22 . 
     Since the web camera  30  is incorporated in the radiation source device  16 , the number of parts of the radiographic image capturing apparatus  10 H is reduced. 
     As shown in  FIG. 25 , a radiographic image capturing apparatus  10 I and a radiographic image capturing system  11 I according to a ninth modification are different from the radiographic image capturing apparatus and the radiographic image capturing systems shown in  FIGS. 1 through 24  in that the console  106  and a plurality of attaché cases  98  each housing the radiographic image capturing apparatus  10 I are provided in a medical examination car  300  (waiting place) on which the doctor  38  is available, and the operator  32  (see  FIG. 5 ) carries at least one of the attaché case  98  from the medical examination car  300  to the site. The cabin of the medical examination car  300  where the doctor  38  is available serves as the waiting place from which the doctor  38  is unable to see the subject  18  directly. 
     The radiographic image capturing apparatus  10 I that has been carried to the site and the communication unit  104  in the medical examination car  300  are capable of sending and receiving signals therebetween by way of wireless communications. For example, the radiographic image capturing apparatus  10 I at the site can send wireless signals representing camera images and radiographic images to the communication unit  104  by way of wireless communications. Therefore, the radiographic image capturing apparatus  10 I offers the same advantages as the radiographic image capturing apparatus shown in  FIGS. 1 through 24 . Though the radiographic image capturing apparatus  10 I and the communication unit  104  are illustrated in  FIG. 25  as sending and receiving signals directly therebetween by way of wireless communications, they may send and receive signals therebetween via the network  36  (see  FIG. 1 ) by way of wireless communications. 
     As shown in  FIGS. 26A through 30B , a radiographic image capturing apparatus  10 J and a radiographic image capturing system  11 J according to a tenth modification are different from the radiographic image capturing apparatus and the radiographic image capturing systems shown in  FIGS. 1 through 25  in that the radiation source device  16  applies radiations  12   a  through  12   c  through the subject  18  to the cassette  22  simultaneously or successively in irradiated ranges which are smaller than the radiation  12  (see  FIG. 1 ). 
     The tenth modification is effective in capturing radiographic images of the subject  18  with the radiations  12   a  through  12   c  applied in the irradiated ranges which are smaller than the radiation  12  when the radiation intensity is set to a weak level and the radiation source device  16  is positioned closely to the cassette  22  for a small SID for better safety against unwanted exposure to the radiation in disaster sites or homes receiving home-care services. 
     In  FIGS. 26A and 26B , the radiation source device  16  houses therein a plurality of radiation sources  14   a ,  14   b ,  14   c  spaced at certain intervals for simultaneously applying the respective radiations  12   a ,  12   b ,  12   c  to the irradiated surface  44  of the cassette  22  after the irradiated field lamp  56  outputs the irradiation light  54 . The radiation sources  14   a ,  14   b ,  14   c  simultaneously output the respective radiations  12   a ,  12   b ,  12   c  such that the areas irradiated by the radiations  12   a ,  12   b  partly overlap each other and the areas irradiated by the radiations  12   b ,  12   c  partly overlap each other. The radiations  12   a ,  12   b ,  12   c  thus applied cover the entire area within the outer frame provided by the guide lines  46 , reliably without any radiation-free gaps in the area. Even if the radiation intensity is set to a weak level, therefore, it is possible to reliably capture a radiographic image of the subject  18 . 
     In  FIGS. 27A through 28B , the radiation source device  16  houses therein a rail  302  extending longitudinally therealong, and the radiation source  14  is movable along the rail  302 . After the irradiated field lamp  56  outputs the irradiation light  54  to the irradiated surface  44 , the radiation source  14  repeatedly moves to certain positions along the rail  302  and applies the radiations  12   a ,  12   b ,  12   c  from respective positions after the radiation source  14  has moved to the certain positions along the rail  302 . The radiation source  14  moves to the positions shown respectively in  FIGS. 27B ,  28 A, and  28 B and applies the radiations  12   a ,  12   b ,  12   c  from those positions such that the areas irradiated by the radiations  12   a ,  12   b  partly overlap each other and the areas irradiated by the radiations  12   b ,  12   c  partly overlap each other. The radiations  12   a ,  12   b ,  12   c  thus applied cover the entire area within the outer frame provided by the guide lines  46 , reliably without any radiation-free gaps in the area. Even if the radiation intensity is set to a weak level, therefore, it is possible to reliably capture a radiographic image of the subject  18 . 
     In  FIGS. 29A through 30B , after the irradiated field lamp  56  outputs the irradiation light  54  to the irradiated surface  44 , the radiation source  14  is repeatedly turned to certain angular positions by a turning mechanism, not shown, and applies the radiations  12   a ,  12   b ,  12   c  from respective positions after the radiation source  14  has been turned to the certain angular positions. The radiation source  14  is turned to the angular positions shown in  FIGS. 29B ,  30 A, and  30 B and applies the radiations  12   a ,  12   b ,  12   c  from those angular positions such that the areas irradiated by the radiations  12   a ,  12   b  partly overlap each other and the areas irradiated by the radiations  12   b ,  12   c  partly overlap each other. The radiations  12   a ,  12   b ,  12   c  thus applied cover the entire area within the outer frame provided by the guide lines  46 , reliably without any radiation-free gaps in the area. Even if the radiation intensity is set to a weak level, therefore, it is possible to reliably capture a radiographic image of the subject  18 . 
     In the tenth modification, the portions of the generated radiographic image which correspond to the overlapping areas irradiated by the radiations  12   a ,  12   b ,  12   c  may be corrected by a known correcting process such as a shading process or the like. In the arrangements shown in  FIGS. 27A through 30B , at least two of the radiation sources  14   a ,  14   b ,  14   c  may be employed to apply the radiations to cover the entire area within the outer frame provided by the guide lines  46 , reliably without any radiation-free gaps in the area, and the sequence in which the radiation source  14  is moved or turned, the positions to which the radiation source  14  is moved, and the angular positions to which the radiation source  14  is turned are not limited to those shown in  FIGS. 27A through 28B  and  FIGS. 29B through 30B , but may be changed appropriately. 
     In  FIGS. 31A through 33B , the subject  18  is positioned using the web camera  30  incorporated in the radiation source device  16 , and a positional deviation of the radiation source device  16  is detected based on the camera image captured by the web camera  30  in the second modification and the eighth modification. 
     As shown in  FIG. 31A , if a horizontal axis  304  extending through the center of the web camera  30  is substantially perpendicular to the central position of the guide lines  46 , then the body region of the subject  18  to be imaged and the cassette  22  are displayed centrally in the camera image that is displayed on the display unit  64  (see  FIG. 1 ) of the mobile information terminal  34  and the display unit  112  of the console  106 , as shown in  FIG. 31B . In  FIG. 31B , the point of intersection of the crisscross lines in the camera image represents the central position of the guide lines  46 . When the horizontal axis  304  is substantially perpendicular to the central position of the guide lines  46 , the point of intersection of the crisscross lines in the camera image is substantially aligned with the central position of the guide lines  46 . 
     In the preparatory procedure, the operator  32  instructs the subject  18  to move or adjusts the position of the radiation source device  16  to bring the point of intersection of the crisscross lines into substantial alignment with the central position of the guide lines  46  while seeing the camera image. Therefore, the operator  32  can easily position the subject  18  even without directly seeing the subject  18 . In  FIG. 31B , a visual message “OK” indicating that the preparatory procedure is completed is displayed when the point of intersection of the crisscross lines is in substantial alignment with the central position of the guide lines  46 , as is the case with the displayed images shown in  FIGS. 14A and 14B . 
     When the image capturing process is performed on the subject  18  which has been positioned as shown in  FIGS. 31A and 31B , a radiographic image of the desired body region is obtained as shown in  FIG. 33A .  FIG. 33A  shows images displayed on the display units  64 ,  112  after the image capturing process is performed. In  FIG. 33A , the radiographic image of the body region of the subject  18  to be imaged is displayed at an enlarged scale, and a camera image of the subject  18  and the cassette  22  after the image capturing process is performed are displayed at a reduced scale together with a visual message “IMAGE CAPTURING PROCESS IS COMPLETED” indicating that the image capturing process is completed, as is the case with the displayed images shown in  FIGS. 15A and 15B . After the image capturing process is performed, it is desirable for the doctor  38  to quickly analyze the radiographic image of the subject  18  in detail for diagnosis. The radiographic image of the body region of the subject  18  to be imaged that is displayed at a scale greater than the other images allows the doctor  38  to quickly and efficiently analyze the radiographic image for diagnosis. 
     If the horizontal axis is not perpendicular to the central position of the guide lines  46 , but deviates widely therefrom, as shown in  FIG. 32A , then it is easy to recognize that the point of intersection of the crisscross lines in the camera image is not in alignment with the central position of the guide lines  46  and the radiation source device  16  positionally deviates from the cassette  22 . 
     In the preparatory procedure, the operator  32  may adjust the position of the radiation source device  16  in order to bring the point of intersection of the crisscross lines into substantial alignment with the central position of the guide lines  46 , i.e., in order to display the image shown in  FIG. 31B , while seeing the camera image. The operator  32  can reliably be notified of positional deviations of the radiation source device  16  with respect to the cassette  22 . In  FIG. 32B , when the radiation source device  16  positionally deviates from the cassette  22 , a visual message “MOVE PATIENT TO CASSETTE” indicating that the preparatory procedure is to be performed again is displayed as is the case with the displayed image shown in  FIG. 14C . 
     If the image capturing process is performed despite the displayed image shown in  FIG. 32B  or if the radiation source device  16  positionally deviates in the image capturing process, then the display units  64 ,  112  display a failure radiographic image, a camera image of the subject  18  and the cassette  22  after the image capturing process, and a visual message “IMAGE CAPTURE FAILURE, PERFORM IMAGE CAPTURING PROCESS AGAIN” indicating that the image capturing process is to be performed again, as is the case with the displayed image shown in  FIG. 15C . Therefore, the operator  32  easily recognizes that the image capturing process has failed and is to be performed again by seeing the displayed images. 
     With the arrangement shown in  FIGS. 31A through 33B , the subject  18  is positioned using the web camera  30  incorporated in the radiation source device  16 , and a positional deviation of the radiation source device  16  is detected based on the camera image captured by the web camera  30 . Therefore, it is possible to reliably notify the operator  32  of the positional deviation in the preparatory procedure. The operator  32  can thus perform the preparatory procedure and reliably acquire desired radiation images. Even in the event of an image capturing process failure, the operator  32  can quickly perform the image capturing process again because the operator  32  is reliably notified of an instruction to perform the image capturing process again. 
     As shown in  FIGS. 34 through 36B , a radiographic image capturing apparatus  10 K and a radiographic image capturing system  11 K according to an eleventh modification are different from the radiographic image capturing apparatus and the radiographic image capturing systems shown in  FIGS. 1 through 33B  in that a handle  310  to be gripped by the operator  32  is disposed on a portion opposite to the portion from which the radiation  12  is emitted. 
     In this case, the operator  32  directs the radiation source device  16  having a built-in web camera  30  toward the subject  18  and the cassette  22  while gripping the handle  310  with one hand, and operates the mobile information terminal  34  with the other hand while looking at the display unit  64 . At this time, because the camera image captured by the web camera  30  is displayed on the display unit  64 , the operator  32  can move the radiation source device  16  to a desired position and can position the subject  18 , while looking at the captured camera image. Further, even if the radiation  12  is emitted while the operator  32  is gripping the handle  310 , irradiation of the radiation  12  to the operator  32  (exposure to radiation) can reliably be avoided. 
     Particularly, at a disaster site surrounded by many obstacles, the eleventh modification is advantageous. Since the disaster site is full of obstacles and further it is difficult to move the subject  18  suffering from injuries or the like, it is not practical to fix the radiation source device  16  and the cassette  22  to predetermined locations and place the subject  18  between the radiation source device  16  and the cassette  22 . In most cases, the radiation source device  16  and the cassette  22  have to be arranged depending on the subject  18 . Therefore, even though the operator  32  can direct the radiation source device  16  toward the subject  18 , the operator may not see the subject  18  directly because of the obstacles, making it difficult to place the subject  18  in the right position. 
     Thus, in the eleventh modification, when the operator  32  grips the handle  310  with one hand to direct the radiation source device  16  toward the subject  18  and the cassette  22  at a disaster site, the web camera  30  captures images of the subject  18  and the cassette  22 , and then the captured camera images are displayed on the display unit  64 . Accordingly, the operator  32  can easily operate the mobile information terminal  34  with the other hand, adjust the position of the radiation source device  16  or place the subject  18  in the right position, while looking at the displayed camera images on the display unit  64 . 
     Also, the handle  310  is provided with a capacitive or resistive touch sensor  312  (see  FIGS. 35 through 36B ). When the operator  32  grips the handle  310 , the palm of the operator  32  touches an electrode (not shown) of the touch sensor  312 . Based on the contact between the palm and the electrode, the touch sensor  312  outputs a detection signal to the radiation source controller  138  and the cassette controller  222  (see  FIG. 10 ). Upon receipt of the detection signal, the radiation source controller  138  or the cassette controller  222  may activate the radiation source device  16  or energize the cassette  22 . 
     Further, as shown in  FIGS. 37A and 37B , a recess  324  may be formed in a portion opposite to the portion from which the radiation  12  is emitted, so as to retractably provide a handle  320  in the recess  324 . The handle  320  may also be provided with a touch sensor  322  functioning as with the touch sensor  312  described above. The handle  320  is housed within the recess  324  as shown in  FIG. 37A  while the operator  32  is not gripping the handle  320  of the radiation source device  16 . On the other hand, when the operator  32  turns the handle  320  around its proximal side, the handle  320  projects from the recess  324  and allows the operator to grip the handle  320 . In this case, the handle  320  and the touch sensor  322  offer the same advantages as the handle  310  and the touch sensor  312  described above. 
     The present invention is not limited to the structural details described above. 
     Specifically, the radiographic image capturing apparatus  10 ,  10 A through  10 K and the radiographic image capturing system  11 ,  11 A through  11 K may be arranged as described above and also as follows: 
     (1) The radiation source device  16 , the cassette  22 , the web camera  30 , and the mobile information terminal  34  are included, the radiation source device  16  and the mobile information terminal  34  are separate from each other, and the web camera  30  is incorporated in the mobile information terminal  34  (see  FIGS. 1 through 17 ,  20 ,  22 , and  25 ). 
     (2) The radiation source device  16 , the cassette  22 , the web camera  30 , and the mobile information terminal  34  are included, the radiation source device  16  and the mobile information terminal  34  are separate from each other, and the web camera  30  is incorporated in the radiation source device  16  (see  FIGS. 18 and 34 ). 
     (3) The radiation source device  16 , the cassette  22 , the web camera  30 , and the mobile information terminal  34  are included, the radiation source device  16  and the mobile information terminal  34  are separate from each other, and the web camera  30  is separate from the radiation source device  16 , the cassette  22 , and the mobile information terminal  34 . 
     (4) The radiation source device  16 , the cassette  22 , the web camera  30 , and the mobile information terminal  34  are included, the radiation source device  16  and the mobile information terminal  34  are integrally combined with each other, and the web camera  30  is incorporated in the mobile information terminal  34  (see  FIG. 21 ). 
     (5) The radiation source device  16 , the cassette  22 , the web camera  30 , and the mobile information terminal  34  are included, the radiation source device  16  and the mobile information terminal  34  are integrally combined with each other, and the web camera  30  is incorporated in the radiation source device  16 . 
     (6) The radiation source device  16 , the cassette  22 , the web camera  30 , and the mobile information terminal  34  are included, the radiation source device  16  and the mobile information terminal  34  are integrally combined with each other, and the web camera  30  is separate from the radiation source device  16 , the cassette  22 , and the mobile information terminal  34 . 
     (7) The radiation source device  16 , the cassette  22 , and the web camera  30  are included, and the radiation source device  16  and the web camera  30  are separate from each other (see  FIG. 23 ). 
     (8) The radiation source device  16 , the cassette  22 , and the web camera  30  are included, and the radiation source device  16  and the web camera  30  are integrally combined with each other (see  FIGS. 24 ,  31 A, and  32 A). 
     In the above arrangements (1) through (8), the camera image captured by the web camera  30  is sent from either one of the communication unit  136  of the radiation source device  16 , the communication unit  170  of the cassette  22 , (the communication unit  218  of the mobile information terminal  34 , the communication unit  262  of the high-voltage power supply  252 ), and the communication unit  260  of the web camera  30  to the communication unit  104  of the medical organization  40  via the network  36 . In other words, the either one of the communication units functions as a camera image communication unit for sending a camera image. 
     In the above arrangements (1) through (8), radiographic image information output from the radiation detector  20  is sent from either one of the communication unit  136  of the radiation source device  16 , the communication unit  170  of the cassette  22 , (the communication unit  218  of the mobile information terminal  34 , the communication unit  262  of the high-voltage power supply  252 ), and the communication unit  260  of the web camera  30 , if any, to the communication unit  104  of the medical organization  40  via the network  36 . 
     In the above arrangements (1) through (8), therefore, signals that are to be sent and received between the radiographic image capturing apparatus  10 ,  10 A through  10 J and the communication unit  104  of the medical organization  40  via the network  36  are sent and received between either one of the communication unit  136  of the radiation source device  16 , the communication unit  170  of the cassette  22 , (the communication unit  218  of the mobile information terminal  34 , the communication unit  262  of the high-voltage power supply  252 ), and the communication unit  260  of the web camera  30 , if any, and the communication unit  104 . 
     In the illustrated embodiment and modifications, signals are sent and received by way of wireless communications and/or wired communications. However, if the subject  18  is held in contact with the radiation source device  16  and the cassette  22  with a short SID, then signals, e.g., a synchronization control signal, may be sent and received between the radiation source device  16  and the cassette  22  by way of intrabody communications through the subject  18  that serves as a signal transmission medium. 
     In a case where the operator  32  contacts both the radiation source device  16  and the mobile information terminal  34  as in the case of the eleventh modification (see  FIGS. 34 through 37B ), signals may be sent and received between the radiation source device  16  and the mobile information terminal  34  by way of intrabody communications through the operator  32  that serves as a signal transmission medium. 
     Although certain preferred embodiments of the present invention have been shown and described in detail, it should be understood that various changes and modifications may be made therein without departing from the scope of the appended claims.