An electronic cassette accommodating a sensor for converting radiation into an electric signal. A cable with a specific length is connected to a side surface of the electronic cassette. A connector that is connectable with a wireless communication unit or an external power source is provided at an end of the cable.

BACKGROUND OF THE INVENTION

1. Filed of the Invention

The present invention relates to an X-ray imaging apparatus used for medical diagnosis and particularly relates to a portable imaging apparatus having an area sensor serving as an X-ray receiving medium in which multiple photoelectric conversion elements are two-dimensionally arranged on the same plane.

2. Related Background Art

It is a widely used method, in the field of nondestructive inspection for industrial purpose and in the field of medical diagnosis, to obtain a radiation image of an object to be imaged by irradiating the object to be imaged with radiation and detecting the intensity distribution of the radiation that has been transmitted through the object to be imaged. Specifically, a general method of obtaining a radiation image of an object includes the steps of preparing a combination of a silver film and a so-called fluorescent screen (or an intensifying screen) that emits fluorescent light upon receiving radiation, irradiating an object to be imaged with X-rays, converting the transmitted radiation into visible light by means of the fluorescent screen to form an latent image on the silver film, and then chemically processing the silver film to obtain a visible image. The radiation image obtained by this method is an analogue photograph, which is to be used for diagnosis, inspection or other purposes.

On the other hand, recently there has been developed technology for obtaining a digital image using a two dimensional array sensor as image receiving means in which pixels composed of micro photoelectric conversion elements or switching elements are arranged in a lattice-like pattern. Such an imaging apparatus can display obtained image data immediately, so that it may be called a direct X-ray digital imaging apparatus. Advantages of the X-ray digital imaging apparatus over conventional analogue photographing technologies are elimination of the need for films, enlargement of obtained image information realized by image processing and capability of constructing a database etc.

Digital image data obtained from an X-ray digital imaging apparatus is transferred to a system control unit or a storage server etc. via wired or wireless data transmission.

X-ray imaging apparatuses for forming still images for medical use are categorized, based on the scheme of imaging of a patient as an object to be imaged, into stationary type apparatuses and portable type apparatuses. An example of the stationary type apparatus is provided with a table and an imaging portion containing a film or a photoelectric conversion apparatus and it radiates X-rays to a patient from above to obtain an abdominal image of the patient. The portable type apparatus uses a lightweight box called a cassette in which a film is accommodated. The portable type apparatus is used in the case that the condition of a patient is too bad to be brought from a bed in a ward to a table in an X-ray room in which a stationary type apparatus is installed or in the case that a special imaging method that cannot be put into practice by a stationary apparatus is required. In the former case, an operator brings a cassette and an portable X-ray imaging apparatus to the patient's ward, so that the operator performs imaging in the ward.

In view of portability and operationality, it is desirable that the portable apparatus be made as compact and lightweight as possible. However, in the case that the X-ray digital imaging apparatus is to be constructed as a portable apparatus (which will be referred to as an electronic cassette hereinafter), the apparatus includes, in order to output an X-ray transmission image of a patient as a digital image data, many components such as a two-dimensional array sensor for receiving an X-ray image, a drive circuit for driving the sensor in accordance with a control signal sent from an X-ray generating apparatus, an amplifier for selecting matrices within the sensor by means of the drive circuit to amplify the data of each matrix, an A/D conversion circuit for converting the output of the amplifier into digital data and a circuit for serializing the image data that has been sequentially digitized by the A/D converting circuit and the drive circuit. Therefore, it is difficult to make the electronic cassette compact and lightweight as compared to the film cassette. In addition, in the case that wireless data transmission is adopted, a memory for temporally storing data and a battery for supplying power to the electronic cassette are further required. This leads to an additional increase in the size and weight of the electronic cassette. In the case that the number of times of imaging with the electronic cassette is small, the size of the memory and the battery can be made small, so that an increase in the weight may be small. However, in order to eliminate the risk of overflow of memory during imaging and the risk of running out of battery, and since the transfer rate of wireless connection is lower than that of wired connection, the wired connection should also be taken into consideration. On the other hand, in the case that the number of times of imaging is large, it is desirable that the connection scheme be specialized to the wired (or cable) connection, the circuitry for wired data transferring be contained in the electronic cassette, which should be made as compact and lightweight as possible, and a cable for the wired connection be connected to the electronic cassette only at the time of imaging and data transmission.

FIG. 6shows an example of a state of use of an electronic cassette that can be connected with a cable. The patient P shown inFIG. 6is a patient lying on a bed48in a ward. The condition of the patient P is so bad that he or she cannot be brought to an X-ray room in which a stationary X-ray imaging apparatus is installed. Therefore, an operator (not shown) brings an electronic cassette49and an portable X-ray generating apparatus34to the patient's ward so as to perform imaging. The electronic cassette49can be detachably connected with a cable5, through which data is transmitted and electric power is supplied, via a connector50. The cable5is connected to a system control portion27and a power source portion28of the electronic cassette49. The system control portion27controls the operations of the overall system such as control commands to the electronic cassette49, receiving of digital image data and communication with the portable X-ray generating apparatus34etc. The power source portion28transforms an AC voltage of a commercial power source into a predetermined DC voltage for the electronic cassette49to supply it to the electronic cassette49. The system control portion27and the power source portion28are accommodated in the same case having wheels (not shown) with a view to improving portability. The cable5is a composite cable including a signal line between the electronic cassette49and the control portion27and a power supply line between the electronic cassette49and the power source portion28. Though two wires for a power system and a signal system respectively are included in the same cable, the wires are separated into a signal line and a power line at the cable end facing the power source portion28and the cable end facing the electronic cassette49.

In one example of imaging, as a first step of the imaging process, the operator inserts the electronic cassette49that is not connected with the cable5between the patient P and the bed48at the position as shown inFIG. 7. The insertion is normally performed from a side of the patient as shown inFIG. 6. The reason why the electronic cassette49is inserted under the unconnected state is to eliminate the troublesome operation of determining the position of the electronic cassette while paying attention to the cable so that the cable will not fall into the imaging area. The electronic cassette49is positioned at the area in which an image of the patient to be obtained. After the electronic cassette49is positioned, the cable5is connected to the connector50. Then, the operator performs, via an interface30of the system control portion27various setting such as setting of imaging conditions necessary for imaging (the X-ray tube voltage, the tube current and the X-ray irradiation time etc), imaging timing, image processing conditions, patient's ID, method of processing input images. The interface30includes a touch panel, a mouse, a keyboard or a foot switch etc. The system control portion27drives the portable X-ray generating apparatus34and the electronic cassette49based on the set imaging conditions. The portable X-ray generating apparatus34includes an X-ray tube35and an X-ray stop37. The X-ray tube35is driven by a power source36for generating a high voltage controlled by the system control portion27to radiate an X-ray beam. The X-ray stop37shapes the X-ray beam in accordance with a change in the imaging area so that unnecessary X-ray irradiation is not performed. The X-ray beam is directed to the patient P lying on the bed48. The electronic cassette49is irradiated with the X-ray beam that has been transmitted through the patient P. The electronic cassette49accommodates a scintillator for converting X-rays into visible light and a photo detector array as an X-ray receiving medium in which thin film transistors (TFT) are arranged similar to those disclosed in Japanese Patent Application Laid-Open No. 08-116043. An X-ray image of the patient that has been irradiated with the X-ray beam is converted into visible light by the scintillator in the interior of the electronic cassette49and the resultant visible light is subjected to photoelectric conversion in the photo detector array. After that, amplification processing and A/D conversion processing are performed, so that serialized digital image data is sent from the electronic cassette to the system control portion27via the signal line of the cable5. The system control portion27performs switching of data to be displayed on a monitor31, real time correction and spatial filtering of the digital image data, tone processing, DR compression etc. The processed image is displayed on the monitor31. The processed digital data is stored in a memory apparatus38at the same time with the real time image processing. Preferably, the memory apparatus38is a data storage apparatus that meets large capacity, high speed and high reliability requirements. For example, hard disk arrays such as RAID are preferable. After the data is stored, the cable5is disconnected from the connector50and the electronic cassette49is drawn out from between the patient P and the bed48. Thus the imaging process is terminated.

The system control portion27is provided with a LAN board (not shown), through which the system control portion27can be connected to a LAN. A file server in which image data is to be filed, an image printer for outputting an image on a film and an image processing terminal for facilitating complex image processing and diagnosis etc. are connected to the LAN. The system control portion27outputs digital image data in accordance with a predetermined protocol (for example, DICOM). After the imaging of the patient P is finished, the operator brings the system to a site at which a port for allowing connection to the LAN is available so as to perform an output operation. The port may be provided in the ward in which the patient P stays so that the output operation may be performed immediately after the completion of imaging.(Reference: Japanese Patent Application Laid-Open No. 2002-82172)

However, the above-described structure of the electronic cassette suffers from the following problems.

FIG. 8shows a case in which a connector provided on an electronic cassette51having the structure same as the above-described electronic cassette49is present between a patient P and a bed48. This situation can occur in the case that the outer size of the electronic cassette51is smaller relative to the patient P. This is the case for example when the width of the body of the patient P is larger than the standard width or when the outer size of the electronic cassette is equivalent to the 12×10 inches size or 10×8 inches size in the case of the film cassette. When the operator places the electronic cassette in position, the cable5has not been connected yet. Then, it is necessary for the operator either to connect the cable while raising up the patient P or to once draw out the electronic cassette51and move the electronic cassette to a position which allows connection with the cable5so as to connect the cable. In any case, it is necessary to change the position relative to the patient P. In addition, there is a risk that the position of the electronic cassette can be displaced and the part to be imaged can deviate from the imaging area. In that case, imaging must be performed again. In addition, since the portable cassette is used not only in the above-described imaging manner but also in various positions for a patient who cannot move, it is necessary for the operator to perform imaging while always paying attention to the position of the connector of the electronic cassette. This is troublesome for the operator.

SUMMARY OF THE INVENTION

Under the above-described situations, an object of the present invention is to provide an X-ray imaging apparatus that has an improved cable connectability.

According to one aspect of the present invention, there is provided an X-ray imaging apparatus comprising:

a sensor for converting radiation into an electric signal;

an electronic cassette for accommodating the sensor;

a first cable connected to a side surface of the electronic cassette; and

a first connector provided at an end of the first cable.

According to another aspect of the present invention, there is provided an X-ray imaging apparatus comprising:

a sensor for converting radiation into an electric signal;

an electronic cassette for accommodating the sensor;

a first cable connected to a side surface of the electronic cassette; and

a first connector provided at an end of the first cable;

a second connector to be connected to the first connector;

a second cable connected to the second connector; and

an external apparatus connected to the second cable for transmitting/receiving an electric signal to/from the electronic cassette via the first and second cables and/or supplying electric power to the cassette.

Other features and advantages of the present invention will be apparent from the following descriptions taken in conjunction with the accompanying drawings, throughout which like reference characters designate the same or similar parts.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

The present invention as defined by the claims will be described based on embodiments illustrated in the drawings.

FIGS. 1A and 1Bare diagrams showing the structure of a first embodiment. Parts equivalent to those in the previously mentioned drawings will be designated by the same reference characters.

What is different in this embodiment from the electronic cassette49shown inFIG. 6is that a cable2is connected to the case of an electronic cassette1and a connector3is provided at the end of the cable2. InFIG. 1B, L1represents the distance from the side surface of the electronic cassette1to which the cable2is connected to the end of the cable3, and X1represents the distance from the center C of the imaging area4of the electronic cassette1to the aforementioned side surface of the electronic cassette1. The electronic cassette1has a connection port for the cable2provided on the aforementioned side surface. InFIG. 1A, Wp represents the shoulder width or the maximum body width defined by Japanese Industrial Standards (JIS) Z8500 (directed to measurement of human body), and line O represents the center line of the body axis.

In the case shown inFIG. 1A, the center C of the imaging area4of the electronic cassette1is positioned on the center line of the body axis O and a cable5is connected to the connector3. In this state, since the electronic cassette1is placed between the patient P and the bed48, it is difficult for an operator to visually observe the electronic cassette1. However, in the electronic cassette1, since the connector3is spaced apart from the body of the electronic cassette1on the connection side A via the cable2, the operator can connect it with the cable5as long as the connecter3projects outside the area of the body of the patient P. The cable5is used for power supply to the electronic cassette1and signal transmission after it is connected, as has been described in connection withFIG. 6.

If the distance L1is set in the range that satisfies the formula L1≧Wp/2−X1, the connector3will be either at a position in the vicinity of the side face of the body of the patient P facing the connection side A at least or at a position in which the connector3projects outside the area of the body of the patient P, and therefore the operator can connect the connector3and the cable5shown inFIG. 1Aeasily. By way of example, it is assumed here that the size of the electronic cassette is JL10×12 size defined by Japanese Industrial Standards (JIS) Z4905 and the Wp is 45 cm, which is approximately the average shoulder width of Japanese adult males. The cable connection side is a long side of the electronic cassette1. In the case that the aforementioned long side is used as the connection side, X1is equal to 281.5/2 mm. Therefore, if L1is larger than 84.25 mm, the cable connecting operation will be easily performed. If Wp in the above formula is set to the maximum body width, the cable will further projects outside the area of the body. This makes the connecting operation easier.

Since the distance L1is a function of X1mainly, when the size of the electronic cassette is increased, L1becomes relatively small. While in the situation shown inFIG. 1A, the center C of the imaging area4is located on the center line of the body axis O, in the case that the electronic cassette1is to be placed in such a way that the center C of the imaging area4is at a position above (in the plane ofFIG. 1A) the center line of the body axis O, the operator can connect the cable in a manner similar to the above by changing, before placing the electronic cassette1, the orientation of the connection side surface of the electronic cassette1in such a way that the connector3projects toward the connection side B.

FIG. 2is a diagram showing the structure of a second embodiment of the present invention. InFIG. 2, the parts same as those in the previously mentioned drawings are designated by the same reference characters.

What is different in this embodiment from the electronic cassette1shown inFIGS. 1A and 1Bis that the electronic cassette has a substantially rectangular shape, the connection port for a cable7is provided on a long side of it, and a connector8is provided at the end of the cable7. The imaging area9also has a substantially rectangular shape. In the situation shown inFIG. 2, the electronic cassette6is disposed in such a way that its long side is perpendicular to the center line of the body axis O of the patient P. Therefore, the connection port for the cable7can hardly be visually observed, since it is beneath the body of the patient P. However, letting L2be the distance from the side surface of the electronic cassette6to which the cable7is connected to the end of the connector8, and letting X2be the distance from the center C of the imaging area9of the electronic cassette6to the above-mentioned side surface of the electronic cassette6, when the distance L2satisfies the formula L2≧Wp/2−X2, the connector8will be either at a position in the vicinity of the side face of the body of the patient P facing the connection side A at least or at a position in which the connector8projects outside the area of the body of the patient P, and therefore the operator can connect the connector8and the cable5shown inFIG. 1Aeasily.

As per the above, since L1and L2do not represent the cable length but the distance from the side surface of the electronic cassette to the connector, they do not depend on the position of the connection port for the cable.

FIG. 3is a diagram showing the structure of a third embodiment of the present invention. InFIG. 3, the parts same as those in the previously mentioned drawings are designated by the same reference characters.

What is different in this embodiment from the electronic cassette49shown inFIG. 6is that a cable11is connected to the case of an electronic cassette10and a connector12is provided at the end of the cable11. InFIG. 3, L3represents the distance from the side surface of the electronic cassette10facing the connection side A to the end of the cable12, and X3represents the distance from the center C of the imaging area13of the electronic cassette10to the aforementioned side surface of the electronic cassette10. The electronic cassette10has a connection port for the cable11provided on the aforementioned side surface. In addition, Wt represents the width of the bed48. Specifically, the width Wt represents the width of the bed48in the direction perpendicular to the body axis of the patient P.

In the case shown inFIG. 3, it is difficult for the operator to visually observe the electronic cassette10, since the electronic cassette is placed between the patient P and the bed48.

If the distance L3is set in the range that satisfies the formula L3≧Wt/2−X3, the connector12will be either at a position in the vicinity of the side face of the body of the patient P facing the connection side A at least or at a position in which the connector12projects outside the area of the body of the patient P even if the center C of the imaging area13of the electronic cassette10is positioned on the center line with respect to the width of the bed48, in other words if the electronic cassette10is positioned at the position farthest from the both sides of the bed48. Therefore the operator can connect the connector12and the cable5shown inFIG. 1Aeasily. After connected, the cable5is used for power supply to the electronic cassette10and signal transmission, as has been described in connection withFIG. 6. By way of example, it is assumed here that the size of the electronic cassette is JL10×12 size defined by Japanese Industrial Standards (JIS) Z4905 and Wt is 90 cm. The cable connection side is a long side of the electronic cassette1. In the case that the aforementioned long side is used as the connection side, X3is equal to 281.5/2 mm. Therefore, if L1is larger than 309.25 mm, the cable connecting operation will be easily performed.

In the case that the electronic cassette10is to be placed at a position in which the center C is displaced from the center line of the bed48toward the connection side B, the operator may change, before placing the electronic cassette10, the orientation of the connection side surface of the electronic cassette10in such a way that the connector12projects toward the connection side B in a manner similar to the embodiment shown inFIGS. 1A and 1B. While in the present embodiment the formulation is made with reference to the width of the bed, it may be made with reference to the width of a top plate of imaging table used in X-ray imaging room directly.

Furthermore, in the arrangement shown inFIG. 3, the connection port for the cable11is provided on the connection side surface of the electronic cassette10. However, since L3does not represent the cable length but the distance from the side surface of the electronic cassette to the connector, it does not depend on the position of the connection port for the cable.

FIG. 4is a diagram showing the structure of a fourth embodiment, in which the interior of an electronic cassette14is illustrated. InFIG. 4, the parts same as those in the previously mentioned drawings are designated by the same reference characters.

The electronic cassette14is mainly composed of a scintillator15, a photo detector array16, an X-ray exposure dose monitor17, an electric circuit board18, a connection controller19, a cable20, a connector21and an indicator22. On the electric circuit board18, there is mounted a drive circuit23, an amplifier24, an A/D conversion circuit25and a serializing circuit26. In addition, cable wiring for signal transmission and power transmission between those components is also provided. On the other hand, a cable5for connecting a system control portion27and a power source portion28to the electronic cassette14is provided with a connector29to be connected with the connector21.

Next, operations of the electronic cassette14and the system control portion under different connection states will be described.

First, under the state in which the connector21of the electronic cassette14side is not connected with the connector29of the system control portion27and the power source portion28side, the components in the electronic cassette14do not operate, since power is not supplied to the electronic cassette14. In addition, the indicator22provided in the connector is not supplied with power, and therefore it does not emit light. The system control portion27detects that the connection has not been established, based on absence of communication with the connection control portion19and sends a command to a monitor31for displaying input information from interface30and image data, to cause the monitor31to display a content indicating the disconnected state.

When the operator connects the connector21on the electronic cassette14side and the connector29on the system control portion27and the power source portion28side after placing the electronic cassette14in position, electric power is supplied from the power source portion28to the connection control portion19via the cable20and the power supply cable32. Upon receiving power supply, the connection control portion19recognize the connection. Once the connector5and the connector20are connected, power is also supplied to the indicator22. Then the connection control portion19causes the indicator to emit blue or bluish light to indicate that the electronic cassette14is out of imaging operation and detachment is allowed, until the connection control portion19receives a command signal for imaging from the system control portion27. Under this state, the power source portion28only supply power required for operations of the components of the connection control portion19and the indicator22. In other words, power has not been supplied to each component of the sensor via the power supply cable32yet. The connection control portion19informs the system control portion27of the fact that the connection with the electronic cassette14has been established via the signal cable33. Based on this information, the system control portion27sends a command to the monitor31to cause it to display a content indicating that the electronic cassette14is in a detachable state.

Next, the operator enters through the interface30an imaging start command for the system control portion27in order to perform the imaging operation. Upon receiving the command, the system control portion27transmits a start command to the connection control portion19. In response to the start command, the connection control portion19transmits a command to the indicator22to cause the indicator to emit red or redish light indicating that detachment is not allowed.

At the same time, the system control portion27sends a command to the monitor31to cause it to display a content indicating that detachment is not allowed.

After the above-described operations are completed, the system control portion27commands the power source portion28so that electric power required for driving of the components of the sensor is supplied from the power source portion28via the power supply cable32. At the same time, the system control portion27transmits an imaging command signal to the electric circuit board18via the signal cable33. In addition, the system control portion27drives the X-ray tube35of a portable X-ray generating apparatus34by means of a high voltage generating power source36, drives an X-ray stop37to set an irradiation field, and causes an X-ray beam to be radiated. The drive circuit23on the electric circuit board18detects an X-ray exposure termination signal from the X-ray exposure dose monitor17, high voltage power application from the high voltage generating power source36or an X-ray tube current signal to drive the TFT switches so as to read out electric charges. In the scintillator15, the base material of the phosphor is exited by high energy X-rays and fluorescence within the visible light range is generated by recombination energy released upon recombination. The fluorescence is either based on the base material itself such as CaWO4or CdWO4or a luminescence center material such as CSI:Ti or ZnS:Ag activated in the base material.

The photo detector array16is provided in close contact with the scintillator15. The photo detector array16converts light generated in the scintillator15into an electric signal. The X-ray exposure dose monitor17is provided for monitoring the X-ray exposure dose. The X-ray exposure dose monitor17directly detect X-rays using a light receiving element made of crystal silicon. Visible light transmitted through the photo detector array16is detected by an amorphous silicon light receiving element laminated on the backside of the substrate of the photo detector array16. The detected information is transmitted to the system control portion27, so that the system control portion27drives the high voltage generating power source36to stop or adjust the X-rays based on that information. The drive circuit23drives the photo detector array16under a control of the system control portion27to read out a signal from each pixel. Matrices in the sensor are subjected to selection by the drive circuit23and digital image data is obtained by processing data of each matrix by the amplifier24for amplifying the data, the A/D conversion circuit25for converting the output of the amplifier into digital data and the serializing circuit26for serializing the image data that has been sequentially digitized by the A/D conversion circuit25and the drive circuit23. The obtained digital image data is transmitted to the system control circuit27and stored in a recording apparatus38.

After the transmission of the digital image data to the system control portion27, the power source portion28stops power supply to the components of the sensor based on a command by the system control portion27.

After the digital image data has been stored in the recording apparatus38and the system control portion has sent the stop command to the power source portion28, the system control portion27transmits an imaging termination command to the connection control portion19via the signal cable33. Upon receiving the command, the connection control portion19transmits a command to the indicator22to cause it to emit bluish light so as to indicate that detachment of the electronic cassette14is allowed. Under this state, the operator may disconnect the connector21and the connector29. The system control portion27sends a command to the monitor31to cause it to display a content indicating that detachment of the electronic cassette14is allowed.

After checking the indicator or the display on the monitor31, the operator disconnects the connector21and the connector29to detach the electronic cassette14. Thus, the imaging operation on the patient P is finished. The filing of the stored digital image data is performed in the manner same as that described in connection with the prior art.

As per the above, with the provision of the indicator, the operator can recognize the operation state of the electronic cassette. Consequently, it is possible to avoid damage on the sensor circuit that can be caused by instantaneous power shutdown due to abrupt disconnection of the connectors while the power is supplied to the sensor. In addition, since the indicator is provided on the connector to be connected, the operator can easily check the indicator as described in the previous embodiment.

FIG. 5is a diagram showing the structure of a fifth embodiment, in which the interior of an electronic cassette39is illustrated. InFIG. 5, the parts same as those in the previously mentioned drawings are designated by the same reference characters.

In this embodiment, an image memory40and a battery41are additionally provided in the interior of the electronic cassette39as components different from those in the electronic cassette14show inFIG. 4. In addition, a wireless communication module42, a connector43that can be connected with a connector29and a control portion44for controlling the communication scheme and operations of the electronic cassette39are provided. The system control portion27is additionally provided with a wireless communication terminal45for communicating with the wireless communication module42. With the provision of the image memory40, the battery41and the wireless communication module42, the operator can use the electronic cassette39on the cableless basis (i.e. without a cable). In the following, the operations of the components will be described.

In the state shown inFIG. 5, nothing is connected to the connector43of the electronic cassette39. Under this state, the control portion44suspends power supply to each component of the sensor from the battery41in accordance with the unconnected state of the connector43. The system control portion27detects that the connection has not been established based on absence of communication with the control portion44of the electronic cassette39and sends a command to a monitor31for displaying input information from interface30and image data, to cause the monitor31to display a content indicating the disconnected state.

In the case that the electronic cassette39is to be used without the cable, the operator connects the wireless communication module42with the connector43. Then, in response to the connection of the wireless communication module42, the control portion44sends a command to cause the battery41to supply power to the wireless communication module42. Thus, the wireless communication module42is supplied with power from the electric energy stored in the battery41in advance so as to be in an operable state. At that time, the battery41supplies only the power required for the operations of the components of wireless communication module42. In other words, power has not been supplied to each components of the sensor via a power supply cable46yet. The control portion44informs the wireless communication terminal45of the fact that wireless communication module42has been connected with the electronic cassette39, through the wireless communication module42. Based on that information from the wireless communication terminal45, the system control portion27sends a command to the monitor31to cause it to display a content indicating that the electronic cassette14is in an operable state on the cableless basis.

Next, the operator enters through the interface30an imaging start command for the system control portion27in order to perform the imaging operation. Upon receiving the command, the system control portion27transmits a start command to the control portion44via the wireless communication terminal45and the wireless communication module42. Upon receiving the command, the control portion44commands the battery41so that power required for driving of the components of the sensor is supplied from the battery41via the power supply cable46. At the same time, the control portion44transmits an imaging command signal to the electric circuit board18via a signal cable47. In addition, the system control portion27drives the X-ray tube35of the portable X-ray generating apparatus34by means of the high voltage generating power source36, drives an X-ray stop37to set an irradiation field, and causes an X-ray beam to be radiated. The drive circuit23on the electric circuit board18detects an X-ray exposure termination signal from an X-ray exposure dose monitor17, high voltage power application from the high voltage generating power source36or an X-ray tube current signal to drive TFT switches so as to read out electric charges in the manner same as the embodiment shown inFIG. 4. In the scintillator15, the base material of the phosphor is exited by high energy X-rays and fluorescence within the visible light range is generated by recombination energy released upon recombination. The photo detector array16converts light generated in the scintillator15into an electric signal.

The X-ray exposure dose monitor17detects the radiated X-rays to transmit information obtained by the detection to the control portion44. The control portion44further transmits the information to the system control portion27via the wireless communication module42and the wireless communication terminal45. The system control portion27drives the high voltage generating power source36to stop or adjust the X-rays based on that information. The drive circuit23drives the photo detector array16under a control of the control portion44to read out a signal from each pixel. Matrices in the sensor are subjected to selection by the drive circuit23and digital image data obtained through the amplifier24, the A/D conversion circuit25and the serializing circuit26is stored in the image memory40. In addition, the control portion44transmits the obtained digital image data to the system control portion27via the wireless communication module42and the wireless communication terminal45, so that the digital image data is stored in the recording apparatus38. Since the data amount of the image data is large, it is desirable that the frequency of the communication wave be in a band of several gigahertz in order to realize communication within a short time. The image data stored in the image memory40is temporally data until the image data is stored in the recording apparatus38, and therefore the control portion44controls to delete the image data stored in the image memory40when informed by the system control portion27of completion of the storing of the data in the recording apparatus38. At the same time, the control portion44commands the battery41to stop the power supply to the components of the sensor. The filing of the digital image data stored in the recording apparatus38is performed in the manner same as that described in connection with the prior art.

While in this embodiment the wireless communication uses a frequency band of several gigahertz, the wireless communication module may be replaced with an optical communication module such as an infrared communication module.

As per the above, in the case that the electronic cassette is used without a cable, troublesome handling of the cable can be eliminated, since the operation of connecting a cable is not necessary. However, since power consumption required for the imaging operation with the electronic cassette is large, it is necessary to increase the capacity of the battery when successive imaging operations are to be enabled. An increase in the capacity leads to an increase in the volume and the weight of the battery such as a lithium ion battery. This may deteriorate operationality of the electronic cassette, which is required to be portable and lightweight.

In view of the above situation, in the embodiment shown inFIG. 5, the connector43of the electronic cassette39side is adapted to be connectable with the connector29of the system control portion27side. When the connector29and the connector43are connected, the system control portion27and the control portion44perform communication and power supply related to the above-described operations of the electronic cassette39through the cables5and20and the connectors29and43. In response to the connection of the connectors29and43, the control portion44switches the communication path and the power supply path to the cable basis. At that time, power is not supplied from the power source portion28to the sensor side, but charging of the battery may be performed if the battery has not been charged up to its full capacity. The control portion44informs the system control portion27of the fact that electronic cassette39is connected with the cable. Upon receiving that information, the system control portion27sends a command to the monitor31to cause the monitor to display a content indicating that the electronic cassette is in an operable state on the cable basis. Next, the operator enters through the interface30an imaging start command for the system control portion27in order to perform the imaging operation. Upon receiving the command, the system control portion27transmits a start command to the control portion44. At the same time, the system control portion27causes the power source portion28to supply power required for driving the components of the sensor of the electronic cassette39. On the other hand, the control portion44transmits an imaging command signal to the electric circuit board18via the signal cable47. The system control portion27sends the command same as that described before to the portable X-ray generating apparatus34so as to cause an X-ray beam to be radiated. In addition, the system control portion27and the control portion44perform the series of communications same as those described before on the cable basis, so that the obtained image data is stored in the recording apparatus38. Then, the system control portion27commands the power source portion28to stop the power supply to the components of the sensor.

As per the above, imaging may be performed with a cable in the case that many imaging operations are to be performed successively, and therefore imaging can be performed without deteriorating portability of the electronic cassette. While in this embodiment the wireless communication module is constructed as a detachable module, the wireless module may be accommodated in the electronic cassette in the case the cassette is used in most cases for a small number of times of imaging on the cableless basis.

As has been described in the foregoing, the X-ray imaging apparatus according to the present invention has a connecting portion for connection with an external apparatus provided at a position within a prescribed distance range from the body of the electronic cassette. With this feature, it can be connected with the external apparatus easily irrespective of the size of the electronic cassette or the body type of the patient. In addition, with the provision of indication of the connection state at the connecting portion, whether attachment/detachment is allowed or not can be easily recognized. Furthermore, with the provision of the wireless communication module at the connecting portion, communication means can be selected in accordance with the state of use of the electronic cassette.

Note that the present invention may be applied to either a system constituted by a plurality of apparatuses (e.g. an image processing apparatuses, interfaces, radiographic apparatuses, X-ray generation apparatuses, and the like) or an arrangement that integrates an image processing apparatus and a radiographic apparatus, or the like.

The present invention is not limited to the above embodiments and carious changes and modifications can be made within the sprit and scope of the present invention. Therefore to apprise the public of the scope of the present invention, the following claims are made.