JP2010121944A - Transportable-type radiation image photographing apparatus and radiological image photographing system - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a transportable-type radiological image photographing apparatus which dispenses with the timing control for the irradiation timing of radiation and the read timing of image data, and which can prevent enlargement of the apparatus and will not narrow the flexibility of photographing, and to provide a radiological image photographing system that uses the apparatus. <P>SOLUTION: The transportable-type radiological image photographing apparatus 1 includes radiation detecting elements 7 provided in two-dimensional shapes; a reading circuit 17 for reading the image data; an irradiation-detecting means 42 for detecting the start and termination of irradiation of radiation; a control means 22, which computes the image data of each radiation detecting element 7 from each image data read for each of frames, from the frame at which the irradiation of radiation is started to the frame next to the frame, at which the irradiation of radiation is terminated; and a reverse-bias power source 14, which applies a reverse-bias voltage on the radiation-detecting element 7 via a bias line 9. The irradiation-detecting means 42 detects the start and termination of the irradiation of radiation, based on the increase and decrease in the current flowing through the bias line 9. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a portable radiographic imaging device and a radiographic imaging system.

  For the purpose of disease diagnosis and the like, radiographic images taken using radiation typified by X-ray images are widely used. Conventionally, such medical radiographic images have been taken using a screen film. In order to digitize radiographic images, CR (Computed Radiography) devices using stimulable phosphor sheets have been developed recently. Then, a radiation image capturing apparatus has been developed in which irradiated radiation is detected by a radiation detection element arranged in a two-dimensional form and acquired as digital image data.

  This type of radiographic imaging device is known as an FPD (Flat Panel Detector), and has been conventionally formed integrally with a Bucky device (see, for example, Patent Document 1). However, in recent years, a portable radiographic image capturing apparatus in which a radiation detection element or the like is accommodated in a housing has been developed and put into practical use (see, for example, Patent Document 2).

  In a radiographic imaging device, electric charges are generated and accumulated in each radiation detection element due to radiation irradiated at the time of radiographic imaging, which are sequentially read out, converted into electrical signals, and detected as image data. The

  For example, as described as a problem in Patent Document 3, in such a radiographic imaging apparatus, generally, the radiation irradiation timing in the radiation generation apparatus and the readout timing of image data in the radiographic imaging apparatus are matched. So control must be done.

  That is, assuming that a period for reading out image data for one screen output from the entire radiation detection elements arranged in a two-dimensional manner is one frame, in normal reading processing, after radiation is emitted from the radiation generator, 1 Irradiation of radiation in the radiation generating apparatus by performing radiation reading processing for one frame or after radiation processing for one frame is performed and before reading processing for the next frame is started. Adjustments have been made so that the timing coincides with the readout timing of image data in the radiographic apparatus.

However, this has a problem that the timing control becomes complicated and troublesome. Therefore, in the radiographic imaging device described in Patent Document 3, when it is detected that radiation has been irradiated while repeating the readout process for each frame at an arbitrary timing, each frame and radiation of the radiation while being irradiated are detected. All the image data for each frame up to the next frame after irradiation is stored in the memory, and finally, the image data of each frame is added for each radiation detection element, for each radiation detection element. It has been proposed to obtain final image data.
JP-A-9-73144 JP-A-6-342099 JP-A-9-140691

  By the way, the method in the radiographic imaging apparatus described in Patent Document 3 has an advantage that it is not necessary to match the radiation irradiation timing in the radiation generating apparatus with the readout timing of image data in the radiographic imaging apparatus. .

  However, in order to make the radiographic imaging apparatus recognize that radiation irradiation has started or ended, a device such as a radiation sensor for detecting radiation is provided in the radiographic imaging apparatus, or an external The apparatus must be configured to notify the radiation imaging apparatus of the start and end of radiation irradiation.

  If the external device is configured to notify the radiation image capturing device of the start or end of radiation irradiation, control such as an interface between the external device and the radiation image capturing device is required, and the radiation image capturing device and the radiation generating device are required. When the manufacturers are different, there is a problem that the control configuration is complicated.

  For this reason, it is preferable that the radiographic imaging apparatus itself be configured to detect the start and end of radiation irradiation, but a configuration such as a radiation sensor for detecting radiation is provided in the radiographic imaging apparatus. Then, especially when the radiographic imaging apparatus is portable, there is a need for a space for providing a radiation sensor and the like, which causes problems such as an increase in the size of the apparatus.

  A portable radiographic imaging device is, for example, carried by an operator such as a radiographer in his / her hand or inserted between a patient's body and a bed. Good. Therefore, it is desirable to use a member or equipment already provided in the radiographic imaging apparatus so that the start and end of radiation irradiation can be detected without increasing the size of the apparatus.

  In addition, for example, when a device such as a radiation sensor is provided in a portable radiographic imaging device, the radiation sensor cannot detect the radiation dose irradiated to the radiographic imaging device unless the radiation sensor is irradiated with radiation. It is necessary to arrange a radiographic imaging device so that it is irradiated. In addition, when a radiation sensor is provided, there is also a restriction on which region of interest (part of the subject to be imaged) is set in the imageable region in the detection unit P (see FIG. 3 and the like) of the radiographic image capturing apparatus. Occurs.

  As described above, the arrangement of the radiographic image capturing device is restricted so that the radiation sensor is irradiated with radiation, and the region where the radiographic image capturing device can be imaged is limited. This is not preferable because the degree of freedom in photographing is narrowed.

  The present invention has been made in view of the above-described problems, and it is not necessary to perform timing control between radiation irradiation timing and image data readout timing, and it is possible to prevent the apparatus from being enlarged and to have a high degree of freedom in photographing. It is an object of the present invention to provide a portable radiographic image capturing apparatus that does not reduce the width of the image and a radiographic image capturing system using the same.

In order to solve the above problem, the portable radiographic imaging device of the present invention is:
A plurality of scanning lines and a plurality of signal lines arranged to cross each other;
A radiation detection element that is provided two-dimensionally in each region partitioned by the plurality of scanning lines and the plurality of signal lines, and generates a charge according to the dose of irradiated radiation;
A scanning drive circuit for sequentially switching the scanning lines to which a voltage for signal readout is applied;
A switch element connected to each of the scanning lines and for discharging the charge accumulated in the radiation detection element to the signal line when the signal readout voltage is applied;
A readout circuit that reads out the charge from the radiation detection element via the signal line and converts the charge into image data for each radiation detection element;
Irradiation detecting means for detecting the start and end of radiation irradiation;
When the period for reading out the image data for one screen output from all of the radiation detection elements is one frame, each frame from the frame where the radiation irradiation is started to the frame after the radiation irradiation is completed Control means for calculating image data for each radiation detection element based on each image data read for each frame;
A reverse bias power source for applying a reverse bias voltage to each radiation detection element via a bias line connected to each radiation detection element;
With
The irradiation detection means detects a current flowing through the bias line, and detects the start and end of the radiation irradiation based on the increase and decrease of the current.

Moreover, the radiographic imaging system of the present invention is
A plurality of scanning lines and a plurality of signal lines arranged to cross each other;
A radiation detection element that is provided two-dimensionally in each region partitioned by the plurality of scanning lines and the plurality of signal lines, and generates a charge according to the dose of irradiated radiation;
A scanning drive circuit for sequentially switching the scanning lines to which a voltage for signal readout is applied;
A switch element connected to each of the scanning lines and for discharging the charge accumulated in the radiation detection element to the signal line when the signal readout voltage is applied;
A readout circuit that reads out the charge from the radiation detection element via the signal line and converts the charge into image data for each radiation detection element;
When the period for reading out the image data for one screen output from all of the radiation detection elements is one frame, each frame from the frame where the radiation irradiation is started to the frame after the radiation irradiation is completed Storage means for storing each image data read for each frame for each radiation detection element;
A reverse bias power source for applying a reverse bias voltage to each radiation detection element via a bias line connected to each radiation detection element;
Irradiation detecting means for detecting a current flowing through the bias line and detecting the start and end of the irradiation of the radiation based on the increase and decrease of the current;
Communication means capable of transmitting each of the image data;
A battery for supplying power to each member;
A portable radiographic imaging device comprising:
A radiation generator for emitting radiation to the portable radiographic imaging device;
Based on the image data read from the portable radiographic imaging device and read out for each frame from the frame where radiation irradiation is started to the next frame after radiation irradiation is completed. A reconstruction device that calculates image data for each radiation detection element;
It is characterized by providing.

  According to the portable radiographic image capturing apparatus and radiographic image capturing system of the system of the present invention, when irradiated with radiation or electromagnetic waves converted from radiation, electrons are detected in each radiation detection element of the portable radiographic image capturing apparatus. A hole pair is generated, and one charge is accumulated in the radiation detection element and read out as image data, but the charge that flows out to the bias line by utilizing the same amount of the other charge that flows out to the bias line. By detecting the current due to, the start and end of radiation irradiation to the portable radiographic imaging device is detected.

  Therefore, using a bias line already provided in a portable radiographic imaging device, for example, by simply providing a resistor, a differential amplifier, etc., the current flowing out to the bias line etc. can be accurately detected, and portable radiographic imaging Since it is possible to detect the start and end of radiation irradiation to the apparatus, it is not necessary to newly provide an apparatus such as a radiation sensor in the portable radiographic imaging apparatus. Therefore, it is possible to accurately detect the start and end of radiation irradiation on the portable radiographic imaging device while accurately preventing the portable radiographic imaging device from becoming large.

  In addition, for example, when the power supply state for the radiation detection element or the like has been switched to the image-capable mode, the image data read operation is started, so that the image data read timing can be arbitrarily set regardless of the radiation irradiation timing. It becomes possible to set to. In addition, since the start and stop of radiation irradiation can be accurately detected as described above, the frame where radiation irradiation has started and the frame where radiation irradiation has stopped (and the next frame) can be accurately identified. it can.

  Therefore, there is no need to control the timing of radiation irradiation and image data read timing, and the frame where radiation irradiation has started and the frame where radiation irradiation has stopped (and the next frame) It is possible to accurately identify and accurately set a frame in which image data is to be stored to generate an effective radiation image.

  In addition, the start and stop of radiation irradiation can be detected without depending on the arrangement of the portable radiographic imaging device or the subject position (region of interest) in the radiographable region of the detection unit of the portable radiographic imaging device. The features of the portable radiographic imaging device can be maintained without narrowing the degree of freedom of imaging.

  Embodiments of a portable radiographic imaging device and a radiographic imaging system according to the present invention will be described below with reference to the drawings. However, the present invention is not limited to the following illustrated examples.

  Hereinafter, the portable radiographic imaging device is simply referred to as a radiographic imaging device. In the following description, a so-called indirect radiographic imaging apparatus that includes a scintillator or the like as a radiographic imaging apparatus and converts the emitted radiation into electromagnetic waves of other wavelengths such as visible light to obtain an electrical signal will be described. The present invention can also be applied to a so-called direct type radiographic imaging apparatus that directly detects radiation with a radiation detection element without using a scintillator or the like.

[Radiation imaging equipment]
First, the radiographic imaging device according to the present embodiment will be described. FIG. 1 is an external perspective view of the radiographic image capturing apparatus according to the present embodiment, and FIG. 2 is a cross-sectional view taken along line AA in FIG. The radiographic imaging apparatus 1 according to the present embodiment is a cassette-type portable radiographic imaging apparatus in which a scintillator 3, a substrate 4, and the like are housed in a housing 2 as shown in FIGS. 1 and 2. It is configured.

  The housing 2 is formed of a material such as a carbon plate or plastic that transmits radiation at least on a surface R (hereinafter referred to as a radiation incident surface R) that receives radiation. 1 and 2 show a case where the housing 2 is a lunch box type formed by the frame plate 2A and the back plate 2B, but the housing 2 is formed integrally, for example, A so-called monocoque type, such as the X-ray imaging apparatus described in Japanese Unexamined Patent Publication No. 2002-31526, can also be used.

  As shown in FIG. 2, a base 31 is disposed on the lower side of the substrate 4 inside the housing 2, and the base 31 includes a PCB substrate 33 on which electronic components 32 and the like are disposed, and a buffer member. 34 etc. are attached. In the present embodiment, a glass substrate 35 for protecting the substrate 4 and the scintillator 3 on the radiation incident surface R side is disposed.

  The scintillator 3 is, for example, a phosphor whose main component is converted into an electromagnetic wave having a wavelength of 300 to 800 nm, that is, an electromagnetic wave centered on visible light when it receives radiation, and that is output. The scintillator 3 is attached to a detection unit P, which will be described later, of the substrate 4.

  In the present embodiment, the substrate 4 is formed of a glass substrate. As shown in FIG. 3, a plurality of scanning lines 5 and a plurality of signal lines are provided on a surface 4 a of the substrate 4 facing the scintillator 3. 6 are arranged so as to cross each other. In each of the small regions r defined by the plurality of scanning lines 5 and the plurality of signal lines 6 on the surface 4a of the substrate 4, radiation detection elements 7 that are photoelectric conversion elements in the present embodiment are provided. In this way, the radiation detection elements 7 are two-dimensionally arranged on the substrate 4, and the entire region r in which the plurality of radiation detection elements 7 are provided, that is, the region indicated by the alternate long and short dash line in FIG. P.

  In the present embodiment, as the radiation detection element 7, the radiation incident from the radiation incident surface R is converted by the scintillator 3 and output, according to the amount of electromagnetic waves (increased according to the radiation dose incident on the scintillator 3). For example, a phototransistor or the like can also be used. Each radiation detection element 7 is connected to a source electrode 8s of a TFT (thin film transistor) 8 as a switch element, as shown in the enlarged views of FIGS. The drain electrode 8 d of the TFT 8 is connected to the signal line 6.

  When the TFT 8 is turned on, that is, when a voltage for signal readout is applied to the gate electrode 8g and the gate of the TFT 8 is opened, the charge accumulated in the radiation detection element 7 is applied to the signal line 6. It is supposed to be released. Here, the structure of the radiation detection element 7 and the TFT 8 in this embodiment will be briefly described with reference to the cross-sectional view shown in FIG. FIG. 5 is a sectional view taken along line XX in FIG.

A gate electrode 8g of a TFT 8 made of Al, Cr or the like is formed on the surface 4a of the substrate 4 so as to be integrally laminated with the scanning line 5, and silicon nitride (laminated on the gate electrode 8g and the surface 4a). The first electrode 74 of the radiation detecting element 7 is connected to the upper portion of the gate electrode 8g on the gate insulating layer 81 made of SiN _x ) or the like via the semiconductor layer 82 made of hydrogenated amorphous silicon (a-Si) or the like. The formed source electrode 8s and the drain electrode 8d formed integrally with the signal line 6 are laminated.

The source electrode 8s and the drain electrode 8d are divided by a first passivation layer 83 made of silicon nitride (SiN _x ) or the like, and the first passivation layer 83 covers both the electrodes 8s and 8d from above. In addition, ohmic contact layers 84a and 84b formed in an n-type by doping hydrogenated amorphous silicon with a group VI element are stacked between the semiconductor layer 82 and the source electrode 8s and the drain electrode 8d, respectively. The TFT 8 is formed as described above.

  In the radiation detecting element 7, an auxiliary electrode 72 is formed by laminating Al, Cr, or the like on the insulating layer 71 formed integrally with the gate insulating layer 81 on the surface 4 a of the substrate 4. A first electrode 74 made of Al, Cr, Mo or the like is laminated on the auxiliary electrode 72 with an insulating layer 73 formed integrally with the first passivation layer 83 interposed therebetween. The first electrode 74 is connected to the source electrode 8 s of the TFT 8 through the hole H formed in the first passivation layer 83.

  On the first electrode 74, an n layer 75 formed in an n-type by doping a hydrogenated amorphous silicon with a group VI element, an i layer 76 which is a conversion layer formed of hydrogenated amorphous silicon, and a hydrogenated amorphous A p layer 77 formed by doping a group III element into silicon and forming a p-type layer is formed by laminating sequentially from below. The order of stacking the p layer 77, the i layer 76, and the n layer 75 may be reversed.

  On the p layer 77, a second electrode 78 made of a transparent electrode such as ITO is laminated and formed so that the irradiated electromagnetic wave reaches the i layer 76 and the like. The radiation detection element 7 is formed as described above. In the present embodiment, as described above, a case where a so-called pin type radiation detection element formed by stacking the p layer 77, the i layer 76, and the n layer 75 is used as the radiation detection element 7 has been described. The radiation detection element 7 is not limited to such a pin-type radiation detection element.

A bias line 9 for applying a reverse bias voltage to the radiation detection element 7 is connected to the upper surface of the second electrode 78 of the radiation detection element 7 via the second electrode 78. The second electrode 78 and the bias line 9 of the radiation detection element 7, the first electrode 74 extended to the TFT 8 side, the first passivation layer 83 of the TFT 8, that is, the upper surfaces of the radiation detection element 7 and the TFT 8 are A second passivation layer 79 made of silicon nitride (SiN _x ) or the like is covered from above.

  As shown in FIGS. 3 and 4, in this embodiment, one bias line 9 is connected to a plurality of radiation detection elements 7 arranged in rows, and each bias line 9 is connected to a signal line 6. Are arranged in parallel with each other. In addition, each bias line 9 is bound to one connection 10 at a position outside the detection portion P of the substrate 4. The bias line 9 and the connection 10 are formed of a metal wire having a small electric resistance.

  In the present embodiment, the connection lines 10 of the scanning lines 5, the signal lines 6, and the bias lines 9 are respectively connected to input / output terminals (also referred to as pads) 11 provided near the edge of the substrate 4. As shown in FIG. 6, a COF (Chip On Film) 12 in which a chip such as an IC 12a is incorporated in each input / output terminal 11 is an anisotropic conductive adhesive film (Anisotropic Conductive Film) or anisotropic conductive paste (Anisotropic paste). It is connected via an anisotropic conductive adhesive material 13 such as Conductive Paste).

  The COF 12 is routed to the back surface 4b side of the substrate 4 and connected to the PCB substrate 33 described above on the back surface 4b side. Thus, the board | substrate 4 part of the radiographic imaging apparatus 1 is formed.

  On the other hand, as shown in FIG. 1, a power switch 36 of the radiographic image capturing apparatus 1, indicators 37 for displaying various operation statuses, and the like are provided on the side surface of the short side on one side of the housing 2. In addition, a cover member 38 for replacing an internal battery (not shown) is provided on the side surface portion, and the radiographic image capturing apparatus 1 transmits and receives data, signals, and the like with an external device in a wireless manner on the cover member 38. An antenna device 39 for performing is embedded and provided.

  The location where the antenna device 39 is provided is not limited to one short side surface portion of the housing 2 as in the present embodiment, but may be provided at another location. Further, the number of antenna devices 39 is not necessarily limited to one, and a necessary number is appropriately provided.

  Here, the circuit configuration of the radiation image capturing apparatus 1 will be described. FIG. 7 is an equivalent circuit diagram of the radiation image capturing apparatus 1 according to the present embodiment.

  As described above, each radiation detection element 7 of the detection unit P of the substrate 4 has the second electrode 78 connected to the bias line 9 and the connection 10, respectively, and the connection 10 is connected to the reverse bias power supply 14. . The reverse bias power supply 14 supplies a reverse bias voltage to be applied to each radiation detection element 7 via the connection 10 and each bias line 9. The reverse bias power supply 14 is connected to the control means 22, and the control means 22 controls the reverse bias voltage applied to each radiation detection element 7 from the reverse bias power supply 14.

  The first electrode 74 of each radiation detection element 7 is connected to the source electrode 8s (denoted as S in FIG. 7) of the TFT 8, and the gate electrode 8g of each TFT 8 (denoted as G in FIG. 7). Is connected to each scanning line 5 extending from the scanning drive circuit 15. Further, the drain electrode 8 d (denoted as D in FIG. 7) of each TFT 8 is connected to each signal line 6.

  When a signal readout voltage is applied from the scanning drive circuit 15 to the gate electrode 8g of the TFT 8 via the scanning line 5, the gate of the TFT 8 is turned on, and the charge accumulated in the radiation detection element 7 is supplied to the source of the TFT 8. The signal is read out from the drain electrode 8d to the signal line 6 through the electrode 8s.

  Each signal line 6 is connected to each readout circuit 17 formed in the readout IC 16. Note that a predetermined number of readout circuits 17 are provided in the readout IC 16, and by providing a plurality of readout ICs 16, readout circuits 17 corresponding to the number of signal lines 6 are provided.

  The readout circuit 17 includes an amplifier circuit 18, a correlated double sampling circuit 19, and an A / D converter 20, and one circuit is provided for each signal line 6. However, in the present embodiment, the A / D converter 20 is common to a plurality of circuits, and each electric signal output from each correlated double sampling circuit 19 is sequentially supplied to the A / D converter 21 via the analog multiplexer 21. The data is transmitted to the D converter 20 and is sequentially converted into a digital value by the A / D converter 20.

  In the readout circuit 17, charges are read from the radiation detection elements 7 through the signal lines 6, and the charges are converted into electric signals by performing charge-voltage conversion and amplification for each radiation detection element 7. ing. The correlated double sampling circuit 19 is represented as CDS in FIG.

  The control means 22 is composed of a microcomputer equipped with a CPU (Central Processing Unit) or the like or a dedicated control circuit, and controls the operation of each member of the radiographic image capturing apparatus 1. The control means 22 is connected to a storage means 23 composed of a RAM (Random Access Memory) or the like.

  As described above, the control means 22 controls the reverse bias power supply 14 to control the reverse bias voltage applied to each radiation detection element 7 or the scanning line 5 for applying a signal readout voltage from the scanning drive circuit 15. Or by controlling the amplification circuit 18 and the correlated double sampling circuit 19 in each readout circuit 17 to read out the electrical signal from each radiation detection element 7.

  The control unit 22 is connected to the antenna device 39 described above, and is further connected to a battery 40 for supplying power to each member such as each radiation detection element 7. As described above, the battery 40 is built in the housing 2 of the radiographic image capturing apparatus 1, and the battery 40 has a connection terminal 41 when the battery 40 is charged by supplying power from the external device to the battery 40. It is attached.

  The connection 10 of the bias line 9 is provided with an irradiation detection means 42, and the irradiation detection means 42 is connected to the control means 22.

  The irradiation detecting means 42 detects a current flowing in the connection 10 in which the bias lines 9 are bundled. In the present embodiment, the irradiation detecting means 42 includes a resistor having a predetermined resistance value connected in series to the connection 10 and a differential amplifier for measuring a voltage between both terminals of the resistor, although not shown. By measuring the voltage between both terminals of the resistor with a differential amplifier, the current flowing through the connection 10 is converted into a voltage value and detected.

  As the resistance provided in the irradiation detecting means 42, a resistor having a large resistance value such as 100 kΩ or 1 MΩ is used in order to amplify a current that does not necessarily increase through the connection 10. The irradiation detection means 42 outputs a voltage value corresponding to the current value flowing through the connection 10 thus detected by conversion to the control means 22.

  If the resistance value of the resistor provided in the irradiation detecting means 42 is large as described above, there is a possibility that the current flowing through the bias line 9 or the connection line 10 will be greatly hindered when reading out the charge accumulated by radiation irradiation, for example. Therefore, it is preferable that the irradiation detection means 42 is provided with a switch or the like so that both terminals of the resistor can be appropriately short-circuited. A method for detecting the irradiated radiation by the irradiation detecting means 42 will be described later.

  In this embodiment, the control means 22 is such that the operator manually operates the power switch 36 (see FIG. 1) or the like, or via the antenna device 39, for example, a console 58 of the radiographic imaging system 50 described later. When a switching signal transmitted from an external device is received, the power supply state to the radiation detection element 7 or the like is supplied in accordance with the switching signal, and the radiation detection element 7 or the like is supplied with power to enable radiographic imaging. Switch between the radiographable mode and the sleep mode in which power is supplied only to necessary members such as the control means 22 and the antenna device 39, and the power supply to the radiation detection element 7 is stopped and radiographic imaging cannot be performed. It has become.

  In addition, after the power supply state is switched to the photographing mode as described above, the control unit 22 sets the power supply state when the irradiation detection unit 42 does not detect radiation irradiation within a predetermined time set in advance. By switching from the photographing enabled mode to the sleep mode, power is prevented from being wasted.

  As will be described later, when the image data is read from each radiation detection element 7, the control means 22 applies the scanning line 5 to which a signal reading voltage is applied from the scanning driving circuit 15 to the first line L 1 and the second line L 2. ,... Are sequentially switched (that is, scanned), and a signal reading voltage is applied to the last line Ln of the scanning line 5 to read out image data for one screen (hereinafter, the image data for one screen is read out). The readout period is called one frame.) Subsequently, the image data readout process is repeated for each frame by sequentially switching from the first line L1.

  Then, the storage of the image data Fa in the storage unit 23 is started from the frame in which it is determined that the irradiation of radiation is started based on the voltage value transmitted from the irradiation detection unit 42. The same readout process is repeated until the next frame (hereinafter also referred to as the (m + 1) th frame) of the frame (hereinafter also referred to as the mth frame) determined that the irradiation of radiation has been completed by the information, For each frame, image data Fa, Fb,..., Fm, Fm + 1 from each radiation detection element 7 are acquired and stored in the storage means 23.

  Further, the control means 22 adds the image data Fa to Fm + 1 acquired in this way to calculate final image data for each radiation detection element 7. Note that the image data Fa to Fm + 1 can be added after being corrected as appropriate.

  Hereinafter, this point will be described in detail, and the operation of the radiation image capturing apparatus 1 according to the present embodiment will be described.

  When the control unit 22 of the radiographic image capturing apparatus 1 switches the power supply state for the radiation detecting element 7 and the like to the radiographable mode, first, the scanning drive circuit 15 applies a signal reading voltage to all the scanning lines 5. Then, all the TFTs 8 connected to the scanning line 5 are turned on, the gates are opened, a predetermined signal is transmitted also to the readout circuit 17, and stored in the radiation detection element 7, the TFT 8, the amplification circuit 18 of the readout circuit 17, and the like. The excess charge is released to the downstream side, and reset processing of the radiation detection element 7 and the readout circuit 17 is performed.

  When the reset process is completed, the control unit 22 subsequently stops the application of the signal readout voltage from the scanning drive circuit 15 to all the scanning lines 5 and turns off the TFTs 8 to close the gates.

  Then, as shown in FIG. 8, the control means 22 applies lines for scanning lines 5 that turn on the TFTs 8 connected by applying a signal readout voltage from the scanning drive circuit 15, for example, lines L 1, L 2, The voltage for reading is sequentially applied from the scanning drive circuit 15 to each scanning line 5 while switching in the order of L3,..., Ln, and the image data from each radiation detecting element 7 connected to each line of the scanning line 5 is transferred. Start reading.

  However, the control unit 22 repeatedly scans one frame of each of the lines L1 to Ln of the scanning line 5 unless it is determined that radiation irradiation has started based on the voltage value transmitted from the irradiation detection unit 42. However, the image data is acquired from each radiation detection element 7, but the image data is overwritten and stored in the storage means 23 for each radiation detection element 7, and unnecessary data is deleted.

  On the other hand, when radiation imaging is performed and radiation irradiation to the radiation imaging apparatus 1 is started, radiation that has passed through the subject enters the scintillator 3 (see FIG. 2), and the scintillator 3 converts the radiation into electromagnetic waves. Then, the electromagnetic wave enters the radiation detection element 7 below the electromagnetic wave.

  When electromagnetic waves enter the radiation detection element 7 and reach the i layer 76 (see FIG. 5) of the radiation detection element 7, electron-hole pairs are generated in the i layer 76, and radiation is applied by applying a reverse bias voltage. According to a predetermined potential gradient formed in the detection element 7, one of the generated electrons and holes (hole in this embodiment) flows out to the bias line 9, and the other charge (in this embodiment) Electrons) are accumulated in the radiation detection element 7.

  Here, since the electric charge flowing out to the bias line 9 flows toward the reverse bias power source 14 and is collected in the connection 10, the current is detected by the irradiation detecting means 42. In the present embodiment, as described above, the current flowing through the connection 10 is converted into a voltage value by the irradiation detection means 42 and output to the control means 22.

  FIG. 9 is a graph showing an example of the transition of the voltage value output when the current flowing through the connection 10 of the bias line 9 is converted into a voltage value by the irradiation detection means 42. As shown in FIG. 9, even in a state where no radiation is irradiated, a slight dark charge (electron-hole pair) is generated in each radiation detecting element 7, and in the case of the above embodiment, the holes are biased. Since it flows out to the line 9, a weak current flows in the connection 10, and a voltage value Va corresponding to the current flows from the irradiation detection means 42.

  Then, when radiation irradiation is started in radiographic imaging, as described above, out of electron-hole pairs generated in the radiation detection element 7, holes start to flow out to the bias line 9 in the present embodiment. A large current flows through the connection 10, and the voltage value V output from the irradiation detecting means 42 begins to increase as shown at time t1 in FIG.

  Therefore, for example, a predetermined threshold value Vth is provided in advance for the voltage value V output from the irradiation detection means 42, and it is determined that radiation irradiation has started at the time tstart when the voltage value V exceeds the threshold value Vth. It is possible to configure.

  Further, when the radiation irradiation is completed, the voltage value V starts to decrease and falls to the level of the voltage value Va corresponding to the dark charge. Therefore, for example, it can be configured that it is determined that the radiation irradiation has ended at the time point tend when the voltage value V output from the irradiation detection means 42 becomes equal to or less than the threshold value Vth.

  In order to determine the start or end of radiation irradiation, instead of providing a threshold value Vth for the voltage value V itself, for example, a threshold value ΔVth is provided for the rate of change ΔV of the voltage value V, and the rate of increase of the voltage value V is determined. The time when ΔV exceeds the threshold value ΔVth is detected as the radiation irradiation start time tstart, and the time when the absolute value of the decrease rate ΔV of the voltage value V exceeds the threshold value ΔVth is detected as the radiation irradiation end time tend. Is also possible.

  As described above, when the control means 22 determines that the irradiation of radiation is started in this way, it starts saving the image data Fa read from each radiation detection element 7 in the storage means 23 from that frame. To do. At that time, the image data Fa to Fm + 1 read in each frame up to the frame (m + 1 frame) next to the frame (m frame) determined that the irradiation of radiation has ended after this frame, Instead of being overwritten and stored in the storage means 23, each radiation detection element 7 and each frame are stored separately in the storage means 23, and all the image data Fa to Fm + 1 are stored without being deleted.

  The image data reading process is performed as follows. That is, one charge (hole in this embodiment) out of the electron-hole pair generated in the radiation detection element 7 by radiation irradiation flows out to the bias line 9 as described above, but the other charge (book) In the embodiment, electrons) are accumulated in the radiation detection element 7.

  Then, the TFT 8 connected to a predetermined line of the scanning line 5 to which the signal readout voltage is applied from the scanning drive circuit 15 is turned on, and the charge accumulated from each radiation detection element 7 through the TFT 8 is turned on. It is emitted to the signal line 6. When the application of the signal readout voltage from the scanning drive circuit 15 is stopped and the TFT 8 is turned off, the charge generated in the radiation detection element 7 is not released to the signal line 6, and the radiation detection element 7 enters the radiation detection element 7. Accumulation resumes.

  On the other hand, the electric charge emitted from the radiation detection element 7 to the signal line 6 is converted into an electric signal, that is, image data by being subjected to charge-voltage conversion and amplification in the readout circuit 17, and sequentially A through the analog multiplexer 21. / D converter 20, converted to a digital value and transmitted to control means 22. The control unit 22 sequentially stores the image data transmitted from the A / D converter 20 in the storage unit 23 in association with the radiation detection element 7.

  When the control unit 22 finishes the reading process for each radiation detection element 7 connected to a predetermined line of the scanning line 5, the scanning line 5 to which the voltage for signal reading is applied from the scanning drive circuit 15 is set to the next line. The image data Fa is sequentially read from the radiation detection element 7.

  When the control unit 22 finishes scanning up to the last line of the scanning line 5 and reads the image data Fa for one screen, the control unit 22 shifts to the next frame, and again for signal readout from the first line L1 of the scanning line 5. Are sequentially switched to repeat the reading process of the image data Fb, Fc,... For each frame.

  Further, when it is determined that the radiation irradiation has been completed, for example, when the voltage value V output from the irradiation detection unit 42 becomes equal to or less than the predetermined threshold Vth, the control unit 22 sets the frame as the mth frame, and the next frame. Image data is read up to the frame (the (m + 1) th frame) to obtain image data Fm and Fm + 1.

  Then, the control means 22 adds the respective image data Fa to Fm + 1 for each frame acquired in this way, and calculates final image data for each radiation detection element 7.

  In addition, since the radiation dose irradiated to the radiographic imaging device 1 can be calculated based on the voltage value (see FIG. 9) output from the irradiation detection unit 42 as described below, for example, the radiation It is also possible to configure such that the image data Fa to Fm + 1 are appropriately corrected on the basis of the dose and then added.

  The dose of radiation irradiated to the radiation imaging apparatus 1 corresponds to, for example, integration of the voltage value V output from the irradiation detection means 42 between the irradiation start time tstart and the irradiation end time tend. It can be calculated by converting to a current value.

  Further, the voltage value V output from the irradiation detection means 42 is configured to peak hold, and the product of the maximum value Vp and the time interval between the irradiation start time tstart and the irradiation end time tend is calculated. The transition of the trapezoidal shape of the voltage value V shown in FIG. 9 is approximated to a rectangular shape to estimate the total amount of the voltage value V, and based on this, the radiation dose irradiated to the radiation imaging apparatus 1 is calculated. It is also possible.

  On the other hand, in the radiographic image capturing apparatus 1 of the present embodiment, as shown in FIGS. 3 and 7, all the bias lines 9 connected to each radiation detection element 7 are bound to one connection 10. The radiation dose calculated as described above is for all the radiation detection elements 7, that is, the entire region of the detection unit P (see FIG. 3). With this configuration, it is possible to detect the start and end of irradiation without depending on the position of the main subject (region of interest) in the imageable region.

  However, in radiographic image capturing, the region where the subject is actually captured is often a region including the central portion of the detection unit P. Therefore, in order to increase the detection accuracy in the region, in order to detect the dose of radiation irradiated to the region including the central portion of the detection unit P, for example, radiation detection provided in a two-dimensional manner as shown in FIG. Among the elements 7, each bias line 9 a connected to the radiation detection element 7 existing at the center of the detection unit P irradiated with the radiation that has passed through the subject is connected to each radiation detection element 7 in another region. In addition to the bias line 9b, it can be configured to bind to the connection 10a.

  Then, by providing the irradiation detection means 42 in the connection 10a and outputting the voltage value V as described above, the dose of radiation irradiated to the central portion of the detection unit P can be calculated. With this configuration, image data Fa to Fm + in accordance with the radiation dose in the central portion of the detection unit P that is likely to capture effective information about the subject in the finally generated radiographic image. 1 can be corrected, and a more accurate radiation image can be generated.

  As described above, according to the radiation imaging apparatus 1 according to the present embodiment, upon receiving irradiation of radiation or electromagnetic waves converted from radiation, electron-hole pairs are generated in each radiation detection element 7, The electric charge is accumulated in the radiation detection element 7 and read out as image data. The other electric charge equivalent to the electric charge flows out to the bias line 9 and flows out to the bias line 9 and the connection 10 that binds them. By detecting the current due to the electric charge, the radiation imaging apparatus 1 is configured to detect the start and end of radiation irradiation.

  Therefore, by using the bias line 9 and the connection 10 already provided in the radiographic image capturing apparatus 1 and simply providing a resistor, a differential amplifier, etc., the current flowing to the bias line 9 and the connection 10 is accurately detected, and the radiation Since it is possible to detect the start and end of radiation irradiation on the image capturing apparatus 1, it is not necessary to newly provide a device such as a radiation sensor in the radiation image capturing apparatus 1. Therefore, it is possible to accurately detect the start and end of radiation irradiation to the radiographic image capturing apparatus 1 while accurately preventing the radiographic image capturing apparatus 1 from becoming large.

  In addition, according to the radiographic image capturing apparatus 1 according to the present embodiment, for example, when the power supply state for the radiation detection element 7 or the like is switched to the radiographable mode, the image data reading operation is started. It is possible to arbitrarily set the readout timing of the image data regardless of the radiation irradiation timing. In addition, since the start and stop of radiation irradiation can be accurately detected as described above, the frame where radiation irradiation has started and the frame where radiation irradiation has stopped (and the next frame) can be accurately identified. it can.

  Therefore, there is no need to control the timing of radiation irradiation and image data read timing, and the frame where radiation irradiation has started and the frame where radiation irradiation has stopped (and the next frame) It is possible to accurately identify and accurately set a frame in which image data is to be stored to generate an effective radiation image.

  Further, as described above, when a device such as a radiation sensor is provided in the radiation image capturing apparatus 1, it is necessary to dispose the radiation image capturing apparatus 1 so that the radiation sensor is irradiated with radiation. There is also a restriction on which region of the imageable region in the detection unit P of the apparatus 1 is to set the region of interest (the part of the subject to be imaged).

  However, as in the present embodiment, the radiation sensor is configured by detecting the current due to the charge flowing out to the bias line 9 and the connection 10 and detecting the start and end of radiation irradiation to the radiation imaging apparatus 1. There is no need to provide radiation, and the start and stop of radiation irradiation can be detected without depending on the arrangement of the radiographic imaging device 1 or the subject position (region of interest) in the radiographable region of the detection unit P of the radiographic imaging device 1. Therefore, the features of the portable radiographic imaging device 1 can be maintained without reducing the degree of freedom of imaging.

  Note that, for the image data for each radiation detection element 7 calculated by adding the acquired image data Fa to Fm + 1 for each frame, similarly to the normal image processing, offset correction processing and gain are performed. Correction processing and the like are performed, and a final radiation image is generated.

  Further, in the present embodiment, a case has been described in which the image data reading operation is started and the reading process is repeated for each frame when the power supply state with respect to the radiation detection element 7 or the like is switched to the imaging enabled mode. However, the present invention is not limited to this, and other than this, for example, a signal transmitted from an external device (for example, a console 58, a switch unit 55, a stroke detection unit 60, etc. in the radiographic imaging system 50 described later) is received. It is also possible to configure so that the above processing is performed when triggered by a manual operation of an operator such as a radiologist.

[Radiation imaging system]
In the radiographic image capturing apparatus 1 of the above-described embodiment, the control unit 22 of the radiographic image capturing apparatus 1 specifies a frame where radiation irradiation is started, a frame next to the frame after irradiation (m + 1 frame), and the like. The case where the image data Fa for each frame is calculated by adding the image data Fa to Fm + 1 read in each frame has been described.

  However, the image data Fa to Fm + 1 or the like for each frame is transmitted from the radiation image capturing apparatus 1 to an external reconstruction device such as a console, and the image data Fa to Fm read by each frame by the reconstruction device. It is also possible to add +1 and calculate the image data for each radiation detection element 7. Therefore, an embodiment of the radiation image capturing system configured as described above will be described below.

  FIG. 11 is a diagram illustrating an overall configuration of the radiographic image capturing system according to the present embodiment. The radiographic imaging system 50 of this embodiment is a system that assumes radiographic imaging performed in, for example, a hospital or clinic, and can be employed as a system that captures medical diagnostic images as radiographic images.

  As shown in FIG. 11, the radiographic imaging system 50 includes, for example, an imaging room R1 that irradiates radiation and images a subject that is a part of the patient (a part to be imaged by the patient), a radiographer, a doctor, and the like. It is arranged in the front chamber R2 where the operator performs various operations such as control of radiation applied to the subject and image processing of the acquired radiation image. The imaging room R1 is often shielded with lead or the like so that radiation does not leak outside.

  In the present embodiment, in the imaging room R1, a Bucky device 51 that can be loaded with the above-described radiographic image capturing device 1 (portable radiographic image capturing device 1) or an X-ray tube (not shown) that generates radiation to irradiate a subject. And a radio access point (base station) 54 provided with a wireless antenna 53 that relays these communications when the radiographic imaging device 1 and the console 58 communicate wirelessly.

  Further, in the front chamber R2, an operation console 56 for controlling radiation irradiation, which includes a switch means 55 for instructing the start of radiation irradiation from the radiation generating device 52, and the radiation imaging apparatus 1 are incorporated. A tag reader 57 for detecting a tag, which will be described later, and a console 58 for controlling the entire radiographic imaging system 50 are provided. The console 58 also functions as a reconstruction device in the present invention, and the storage means 59 configured by a hard disk or the like is connected to the console 58.

  Although the configuration of the radiographic image capturing apparatus 1 is as described above, in the present embodiment, the radiographic image capturing apparatus 1 preferably further has the following configuration.

  Specifically, a tag (not shown) is incorporated in the radiation image capturing apparatus 1. In this embodiment, a tag called a so-called RFID (Radio Frequency IDentification) tag is used as the tag, and the tag stores a control circuit that controls each part of the tag and a storage that stores unique information of the radiographic imaging apparatus 1. The part is built in compactly. The unique information includes, for example, a cassette ID, scintillator type information, size information, resolution, and the like as identification information assigned to the radiation image capturing apparatus 1.

  Moreover, in this embodiment, the radiographic imaging device 1 is comprised by the dimension based on JISZ4905 (corresponding international standard is IEC 60406) in the cassette for conventional screens / films. That is, the thickness in the radiation incident direction is within a range of 15 mm + 1 mm to 15 mm-2 mm, and is 8 inches × 10 inches, 10 inches × 12 inches, 11 inches × 14 inches, 14 inches × 14 inches, 14 inches × 17 inches. (Half cut size) etc. are prepared.

  Thus, in this embodiment, since the radiographic imaging device 1 is formed in accordance with the JIS standard relating to the screen / film cassette, a CR cassette formed in accordance with the JIS standard can be loaded in the same manner. It can be used by being loaded on a bucky device 51 for a CR cassette.

  In addition, this invention is not limited to the case where the radiographic imaging device 1 is formed in conformity with the JIS standard as described above, or the case where the bucky device 51 for CR cassette is used as the bucky device 51. However, if the bucky device 51 for CR cassette is used as the bucky device 51, it is possible to carry out radiographic imaging by loading both the radiographic imaging device 1 as FPD and the conventional CR cassette into the bucky device 51. It becomes.

  On the other hand, the radiographic image capturing apparatus 1 can be used in a so-called independent state that is not loaded in the bucky apparatus 51. That is, the radiation image photographing apparatus 1 is arranged in a single state on, for example, a support stand provided in the photographing room R1 or a bucky device 51B for lying position photographing as shown in FIG. 1) and the patient's hand as the subject can be placed on the head, or can be used, for example, inserted between the patient's waist or legs lying on the bed and the bed. ing.

  In this case, for example, radiographic imaging is performed by irradiating the radiographic imaging apparatus 1 with radiation from a portable radiation generating apparatus 52B (see FIG. 11) or the like via a subject.

  The bucky device 51 is provided with a cassette holding portion 51a for holding the radiographic image capturing device 1 in a predetermined position, and the radiographic image capturing device 1 can be loaded into the cassette holding portion 51a. Further, in the present embodiment, as the bucky device 51, there are provided a bucky device 51A for standing position shooting and a bucky device 51B for standing position shooting.

  It should be noted that in the bucky device 51A for standing position photography and the bucky device 51B for standing position photography, for example, it is possible to appropriately adjust the position of the device itself or the height of the cassette holding portion 51a with respect to the bucky device body. It is the same as that of a known Bucky device.

  The imaging room R1 is provided with at least one radiation generating device 52 that includes an X-ray tube that irradiates the radiation imaging apparatus 1 with radiation via a subject. In the present embodiment, one radiation generating device 52A is shared by the bucky devices 51A and 51B for standing position shooting and lying position shooting. It should be noted that it is also possible to configure each of the bucky devices 51A and 51B in association with a separate radiation generating device.

  The radiation generating device 52A is arranged suspended from the ceiling of the photographing room R1, for example, and is set up based on an instruction from an operation console 56 (to be described later) at the time of photographing. It is moved to a position, and its direction is adjusted so that the radiation direction of the radiation faces a predetermined direction.

  In the present embodiment, a portable radiation generation device 52B that is not associated with the standing-up imaging device 51A and the standing-up imaging device 51B is also provided. It can be carried to any place in the photographing room R1, and can be irradiated with radiation in any direction.

  In the present embodiment, the portable radiation generation device 52B is also set up based on an instruction from the console 56. In addition to this, for example, an operator can manually set up, It is also possible to set up by transmitting a radio signal from the radiation imaging apparatus 1 to the portable radiation generation apparatus 52B.

  As the X-ray tube of the radiation generator 52, a rotating anode X-ray tube is preferably used. An X-ray tube is often configured to generate radiation by causing an electron beam emitted from a cathode to collide with an anode. However, if an electron beam continues to collide with the same position on the anode, The anode is damaged due to the occurrence. Therefore, in the rotating anode X-ray tube, the anode is extended so that the position where the electron beam collides does not become the same position, thereby extending the life of the anode.

  In addition, a radio access point 54 having a radio antenna 53 that relays the communication when the radiographic image capturing apparatus 1 and the console 58, the switch means 55, and the like perform wireless communication is provided at one corner in the imaging room R1. is set up.

  Note that FIG. 11 shows a case where the wireless access point 54 is provided near the entrance of the imaging room R1, but the present invention is not limited to this, and wireless communication with the antenna device 39 and the like of the radiographic imaging device 1 is possible. It is installed at an appropriate position where possible. In the present embodiment, the wireless access point 54 is connected to each of the bucky devices 51A and 51B via a cable or the like, and communicates with the bucky devices 51A and 51B or the radiographic imaging device 1 loaded therein and the console 58 or the like. It can also be performed by a wired system.

  On the other hand, the front room R2 is provided with an operation console 56 provided with a switch means 55 for instructing the start of radiation irradiation from the radiation generator 52. In FIG. 9, the console 56 and the switch means 55 are described as separate bodies. In fact, they are provided as separate bodies, and the switch means 55 is easily operated by an operator such as a radiologist. In some cases, the switch means 55 may be provided in a single position, that is, the switch means 55 may be provided on the console 56.

  The console 56 includes a computer having a general-purpose CPU (Central Processing Unit), a computer having a dedicated processor, or the like. In the present embodiment, the console 56 is connected to the switch means 55 and the radiation generator 52 and also to the console 58.

  The switch means 55 transmits a start signal to the console 56 when a button (not shown) is pushed about half in the stroke direction (that is, when the button is half-pressed), and the radiation generator 52 designated by the console 56 is transmitted. When the activation signal is transmitted to the X-ray tube, the rotation of the anode of the X-ray tube of the radiation generating device 52 is started and the radiation generating device 52 is activated.

  Then, after a period of about 1 second, when the button of the switch means 55 is further pushed in and is pushed in all in the stroke direction (that is, when it is fully pushed), the switch means 55 is placed on the console 56. When the irradiation signal is transmitted and the irradiation signal is transmitted from the console 56 to the designated radiation generation device 52, the radiation is irradiated from the X-ray tube of the radiation generation device 52.

  The switch means 55 is provided with a stroke detecting means 60 for detecting a half-pressed state or a full-pressed state of the button and transmitting a detection signal to the console 58. In addition, it is also possible to configure so that the stroke detection means 60 is not provided and these signals are also transmitted to the console 58 when the activation signal or the like is transmitted from the switch means 55 to the console 56.

  In the vicinity of the entrance of the front chamber R2, a tag reader 57 (see FIG. 9) for exchanging information with the radiation imaging apparatus 1 using the RFID technology described above is installed. The tag reader 57 transmits predetermined instruction information on radio waves or the like via a built-in antenna (not shown), and detects the radiographic imaging apparatus 1 that enters or leaves the front room R2 or the imaging room R1. Yes.

  The tag reader 57 reads the unique information stored in the detected RFID tag of the radiographic imaging device 1 and transmits the read unique information to the console 58.

  A console 58 is provided in the front chamber R2. The console 58 is composed of a computer in which a CPU, a ROM (Read Only Memory), a RAM (Random Access Memory), an input / output interface and the like (not shown) are connected to the bus, and reads a predetermined program stored in the ROM. It expands in the work area of the RAM and executes various processes according to the program to control the entire radiographic imaging system 50 as described above.

  The console 58 is connected to the above-described wireless access point 54, console 56, tag reader 57, storage means 59, stroke detecting means 60 attached to the switch means 55, and the like, and via the wireless access point 54. Bucky devices 51A and 51B for standing position shooting and lying position shooting are connected.

  The console 58 is provided with a display screen 58a composed of a CRT (Cathode Ray Tube), an LCD (Liquid Crystal Display), or the like, and other input means such as a keyboard and a mouse are connected thereto.

  When the console 58 receives the unique information including the cassette ID of the radiographic imaging apparatus 1 detected by the tag reader 57 as described above, the radiation existing in the imaging room R1 and the like registered in the storage unit 59 is transmitted to the console 58. A list of the image capturing device 1 is referred to. If the transmitted unique information is not registered in the storage means 59, the console 58 assumes that the radiographic imaging device 1 is newly brought into the radiographic room R1 or the front room R2, and the radiographic imaging thereof is performed. The cassette ID or the like of the device 1 is added to the above list and registered in the storage unit 59.

  If the transmitted unique information is already registered in the storage means 59, the radiographic image capturing apparatus 1 is assumed to have been taken out of the radiographing room R1 or the front room R2. Delete the cassette ID etc. from the above list. In this way, the console 58 grasps the radiation image photographing apparatus 1 brought into or taken out from the photographing room R1 or the like and manages it on the storage means 59.

  In the present embodiment, the console 58 provides a wireless access point to the radiographic imaging apparatus 1 designated by an operator's input operation such as clicking on the radiographic imaging apparatus 1 icon displayed on the display screen 58a. The switching signal can be transmitted via the terminal 54.

  As described above, when the radiographic imaging device 1 receives the switching signal, if the power supply state for the radiation detection element 7 or the like is in the sleep mode, the radiographic imaging device 1 switches to the radiographable mode and supplies power to the radiation detection element 7 or the like. Supply and awaken to a state where radiographic imaging is possible. In addition, when the power supply state for the radiation detection element 7 or the like is switched to the radiographable mode, the radiographic image capturing apparatus 1 starts the image data read operation and repeats the read process for each frame. Is as described above.

  As described above, the radiographic imaging apparatus 1 can be configured to start the image data reading operation at the same time as being switched to the radiographable mode by the switching signal transmitted from the console 58. It is also possible to configure the radiographic imaging device 1 to start the image data reading operation when the button of the switch means 55 of the console 56 is half-pressed and the activation signal is transmitted to the radiation generator 52. It is.

  In this case, when the console 58 receives a detection signal from the stroke detection means 60 that has detected that the button of the switch means 55 of the console 56 has been half-pressed, or receives an activation signal from the switch means 55, the console 58 A signal is transmitted to the radiographic imaging apparatus 1 via 54 to cause the radiographic imaging apparatus 1 to start an image data reading operation.

  After the radiation image capturing apparatus 1 is switched to the image capturing mode and the image data reading operation is started, when radiation is irradiated from the radiation generating apparatus 52 after a long time has elapsed, the battery of the radiation image capturing apparatus 1 is used. 40 may be consumed. However, if the radiographic imaging device 1 is configured to start the image data reading operation at the stage when the activation signal is transmitted to the radiation generation device 52 as described above, after the button of the switch means 55 is pressed halfway. Since the time until it is fully pressed and irradiated with radiation is about 1 second as described above, it is possible to prevent the battery 40 of the radiographic imaging apparatus 1 from being consumed.

  However, there are many cases where the console 58 or the like is not provided in the front chamber R2 of the imaging room R1 as in the radiographic imaging system 70 shown in FIG. 12, for example. In some cases, radiographic image capturing in a plurality of imaging rooms R1 is managed, or a plurality of consoles 58 and a plurality of imaging rooms R1 are connected via a network or the like.

  If the console 58 is not provided in the anterior chamber R2 as described above, the stroke detection means 60 and the switch means 55 are connected to the wireless access point 54 as shown in FIG. It can be configured to transmit directly to the imaging apparatus 1.

  Next, processing in the console 58 as a reconstruction device of the radiographic imaging system 50 according to the present embodiment will be described, and the operation of the radiographic imaging system 50 will be described together.

  In the present embodiment, as described above, the console 58 receives a switching signal for switching the power supply state for the radiation detection element 7 and the like to the radiographable mode for the designated radiographic imaging device 1, and the stroke detection means 60. And a signal such as a start signal from the switch means 55 are transmitted to start the image data reading operation, and the reading process for each frame is repeated as shown in FIG.

  When radiation imaging is performed and radiation irradiation is started from the radiation generation device 52, the radiation imaging device 1 detects the radiation irradiation start time tstart and the irradiation end time tend as described above. Together with the information of the times tstart and tend, the next frame of the frame (m-th frame) from which it was detected that the irradiation of radiation was detected from the frame where it was detected that the irradiation of radiation was started ( Image data Fa to Fm + 1 for each frame up to (m + 1th frame) is transmitted to the console 58. Further, if the irradiation detecting means detects the dose of the irradiated radiation, the information is also transmitted.

  Note that if the image data Fa to Fm + 1 for each frame is transmitted to the console 58, there is a possibility that power for data transmission may be consumed. Therefore, the image data Fa for each frame is used in the radiographic image capturing apparatus 1. ˜Fm + 1 may be added, and each total value for each radiation detection element 7 may be transmitted to the console 58.

  When the console 58 receives image data Fa to Fm + 1 and the like from the radiographic image capturing apparatus 1, the console 58 adds them for each radiation detection element 7, and the total value thereof is used as image data for each radiation detection element 7. Calculate and store in the storage means 59. When the addition processing is performed by the radiation image capturing apparatus 1, the total value for each radiation detection element 7 transmitted from the radiation image capturing apparatus 1 is stored in the storage unit 59 as image data for each radiation detection element 7. Let

  And if the information of the dose of the radiation irradiated from the radiographic imaging device 1 is transmitted, the console 58 corrects the gain correction value according to the dose, and the gain correction processing, the offset correction processing, etc. The final radiation image is generated by performing the image processing.

  When the irradiation detection unit of the radiographic imaging device 1 detects only the start and end of radiation irradiation and cannot detect the radiation dose, the console 58 is used for the radiation generator 52 and the console 56. Based on the information of the irradiation start time tstart and the irradiation end time tend obtained from the above, and the dose per time of the radiation set to irradiate the radiation incident surface R of the radiation image capturing apparatus 1 It is possible to configure so as to calculate the dose of radiation applied to 1.

  Note that the dose of radiation absorbed by the subject may vary depending on the nature of the subject that is the subject of radiographic imaging. Therefore, for example, the radiation of the radiation that reaches the radiation incident surface R of the radiographic imaging device 1 based on information on the body of the patient, such as the imaging region of the patient's body, which is the subject, and the patient's body weight (that is, the amount of subcutaneous fat). It is possible to correct the dose per unit time and calculate the dose of radiation applied to the radiographic imaging device 1 based on the corrected dose per unit time of the radiation.

  As described above, according to the radiographic image capturing system 50 according to the present embodiment, as in the case of the embodiment of the radiographic image capturing apparatus 1 described above, when receiving radiation or electromagnetic waves converted from radiation, An electron-hole pair is generated in each radiation detection element 7 of the image capturing apparatus 1, and one charge is accumulated in the radiation detection element 7 and read out as image data. 9 is configured to detect the start and end of radiation irradiation to the radiographic imaging apparatus 1 by detecting the current due to the electric charge flowing to the bias line 9 and the connection line 10 in which the bias line 9 is bundled. did.

  Therefore, by using the bias line 9 and the connection 10 already provided in the radiographic image capturing apparatus 1 and simply providing a resistor, a differential amplifier, etc., the current flowing to the bias line 9 and the connection 10 is accurately detected, and the radiation Since it is possible to detect the start and end of radiation irradiation on the image capturing apparatus 1, it is not necessary to newly provide a device such as a radiation sensor in the radiation image capturing apparatus 1. Therefore, it is possible to accurately detect the start and end of radiation irradiation to the radiographic image capturing apparatus 1 while accurately preventing the radiographic image capturing apparatus 1 from becoming large.

  In addition, according to the radiographic image capturing apparatus 1 according to the present embodiment, for example, when the power supply state for the radiation detection element 7 or the like is switched to the radiographable mode, the image data reading operation is started. It is possible to arbitrarily set the readout timing of the image data regardless of the radiation irradiation timing. In addition, since the start and stop of radiation irradiation can be accurately detected as described above, the frame where radiation irradiation has started and the frame where radiation irradiation has stopped (and the next frame) can be accurately identified. it can.

  Therefore, there is no need to control the timing of radiation irradiation and image data read timing, and the frame where radiation irradiation has started and the frame where radiation irradiation has stopped (and the next frame) It is possible to accurately identify and accurately set a frame in which image data is to be stored to generate an effective radiation image.

  Further, as described above, when a device such as a radiation sensor is provided in the radiation image capturing apparatus 1, it is necessary to dispose the radiation image capturing apparatus 1 so that the radiation sensor is irradiated with radiation. There is also a restriction on which region of the imageable region in the detection unit P of the apparatus 1 is to set the region of interest (the part of the subject to be imaged).

  However, like the radiographic imaging device 1 of the radiographic imaging system 50 of the present embodiment, the current due to the electric charge flowing out to the bias line 9 and the connection 10 is detected, and the radiation imaging apparatus 1 starts and ends irradiation. It is no longer necessary to provide a radiation sensor, and the start and stop of radiation irradiation can be determined by the arrangement of the radiation image capturing apparatus 1 and the subject in the imageable region of the detection unit P of the radiation image capturing apparatus 1. Since detection is possible without depending on the position (region of interest), the features of the portable radiographic image capturing apparatus 1 can be maintained without narrowing the degree of freedom of imaging.

  Needless to say, the present invention is not limited to the above-described embodiments and modifications, and can be changed as appropriate.

It is a perspective view which shows the radiographic imaging apparatus which concerns on this embodiment. It is sectional drawing which follows the AA line in FIG. It is a top view which shows the structure of the board | substrate which concerns on this embodiment. FIG. 4 is an enlarged view showing a configuration of an imaging element, a thin film transistor, and the like formed in a small region on the substrate of FIG. 3. It is sectional drawing which follows the XX line in FIG. It is a side view explaining the board | substrate with which COF, a PCB board | substrate, etc. were attached. It is a figure showing the equivalent circuit schematic of the radiographic imaging apparatus which concerns on this embodiment. It is a figure which shows the timing chart at the time of switching the voltage for signal reading from a scanning drive circuit sequentially, and applying to each line of a scanning line. It is a graph showing an example of transition of the voltage value output when the electric current which flows through the connection of a bias line is converted into a voltage value by the irradiation detection means. It is a figure which shows the structural example which tied the bias line connected to the element which exists in the center part of a detection part, and the bias line connected to the element of another area | region by separate connection. It is a figure which shows the whole structure of the radiographic imaging system which concerns on this embodiment. It is a figure which shows the whole structure of the radiographic imaging system in case a console etc. are not provided in a front chamber.

Explanation of symbols

1 Radiographic imaging device (portable radiographic imaging device)
5 Scanning line 6 Signal line 7 Radiation detection element 8 TFT (switch element)
9 Bias line 14 Reverse bias power supply 15 Scan drive circuit 17 Read circuit 22 Control means 23 Storage means 39 Antenna device (communication means)
40 Battery 42 Irradiation detection means 50, 70 Radiation imaging system 52 Radiation generator 58 Console (reconstruction means)
Fa to Fm, Fm + 1 Image data m The m-th frame (the frame where radiation irradiation has ended)
m + 1 m + 1 frame (next frame after m frame)
r region

Claims (8)

A plurality of scanning lines and a plurality of signal lines arranged to cross each other;
A radiation detection element that is provided two-dimensionally in each region partitioned by the plurality of scanning lines and the plurality of signal lines, and generates a charge according to the dose of irradiated radiation;
A scanning drive circuit for sequentially switching the scanning lines to which a voltage for signal readout is applied;
A switch element connected to each of the scanning lines and for discharging the charge accumulated in the radiation detection element to the signal line when the signal readout voltage is applied;
A readout circuit that reads out the charge from the radiation detection element via the signal line and converts the charge into image data for each radiation detection element;
Irradiation detecting means for detecting the start and end of radiation irradiation;
When the period for reading out the image data for one screen output from all of the radiation detection elements is one frame, each frame from the frame where the radiation irradiation is started to the frame after the radiation irradiation is completed Control means for calculating image data for each radiation detection element based on each image data read for each frame;
A reverse bias power source for applying a reverse bias voltage to each radiation detection element via a bias line connected to each radiation detection element;
With
The irradiation detection means detects a current flowing through the bias line, and detects the start and end of the irradiation of the radiation based on the increase and decrease of the current.   The portable radiation image capturing apparatus according to claim 1, wherein the irradiation detection unit detects the dose of the irradiated radiation based on a current flowing through the bias line.   The control means adds the image data read for each frame from a frame where the radiation irradiation is started to a frame next to the frame where the radiation irradiation is completed, thereby adding the radiation detection element. The portable radiographic image capturing apparatus according to claim 1, wherein image data for each is calculated.   The control means is configured to supply power to the radiation detection element, a radiographable mode that enables radiographic imaging by supplying power to the radiation detection element, and supplies the power only to necessary members to detect the radiation. It is possible to switch between the sleep mode in which the supply of power to the element is stopped and radiographic imaging cannot be performed, and when the power supply state is switched to the imaging enable mode, the signal is read out to the scanning drive circuit 4. The readout of the image data for each of the frames is started by applying the readout voltage while sequentially switching the scanning lines to which the application voltage is applied. The portable radiographic imaging device according to any one of the above.   The control means switches the power supply state from the radiographable mode to the radiographing element when the radiation is not irradiated within a predetermined time after switching the power supply state to the radiographic detection element to the radiographable mode. The portable radiographic image capturing apparatus according to claim 4, wherein the portable radiographic image capturing apparatus is switched to a sleep mode. A plurality of scanning lines and a plurality of signal lines arranged to cross each other;
A radiation detection element that is provided two-dimensionally in each region partitioned by the plurality of scanning lines and the plurality of signal lines, and generates a charge according to the dose of irradiated radiation;
A scanning drive circuit for sequentially switching the scanning lines to which a voltage for signal readout is applied;
A switch element connected to each of the scanning lines and for discharging the charge accumulated in the radiation detection element to the signal line when the signal readout voltage is applied;
A readout circuit that reads out the charge from the radiation detection element via the signal line and converts the charge into image data for each radiation detection element;
When the period for reading out the image data for one screen output from all of the radiation detection elements is one frame, each frame from the frame where the radiation irradiation is started to the frame after the radiation irradiation is completed Storage means for storing each image data read for each frame for each radiation detection element;
A reverse bias power source for applying a reverse bias voltage to each radiation detection element via a bias line connected to each radiation detection element;
Irradiation detecting means for detecting a current flowing through the bias line and detecting the start and end of the irradiation of the radiation based on the increase and decrease of the current;
Communication means capable of transmitting each of the image data;
A battery for supplying power to each member;
A portable radiographic imaging device comprising:
A radiation generator for emitting radiation to the portable radiographic imaging device;
Based on the image data read from the portable radiographic imaging device and read out for each frame from the frame where radiation irradiation is started to the next frame after radiation irradiation is completed. A reconstruction device that calculates image data for each radiation detection element;
A radiographic imaging system comprising:   The radiation image capturing system according to claim 6, wherein the irradiation detection unit of the portable radiation image capturing apparatus detects the dose of the irradiated radiation based on a current flowing through the bias line.   The reconstruction device adds the image data read for each frame from the frame where the radiation irradiation is started to the frame after the frame where the radiation irradiation is completed, thereby adding the portable type 8. The radiographic image capturing system according to claim 6, wherein image data for each radiation detection element of the radiographic image capturing apparatus is calculated.

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