JP2011247605A - Radiation image photographing device and radiation image processing system - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a radiation image photographing device capable of detecting the start of irradiation of radiation or the like in a device itself and acquiring image data so that the image data in which a part of electric charges useful for irradiation start point of the radiation is lost may be effectively restored in the following image processing.SOLUTION: A control means 22 of the radiation image photographing device 1 performs reading processing by sequentially applying on voltage to each scan line 5 from before photographing of a radiation image to store the image data d for every radiation detection element 7 in a storage means 40, stops the reading processing when the start of irradiation of the radiation is detected based on a value of current output from a current detection means 43, shifts to an electric charge accumulation mode for accumulating electric charges generated by the irradiation of the radiation by applying off voltage to each scan line 5 in each radiation detection element 7, and performs the reading processing by sequentially applying the on voltage to each scan line 5 again after the irradiation of the radiation ends to store image data D in the storage means 40 for every radiation detection element 7.

Description

  The present invention relates to a radiographic image capturing apparatus and a radiographic image processing apparatus.

  A so-called direct type radiographic imaging device that generates electric charges by a detection element in accordance with the dose of irradiated radiation such as X-rays and converts it into an electrical signal, or other radiation such as visible light with a scintillator or the like. Various so-called indirect radiographic imaging devices have been developed that convert charges to electromagnetic waves after being converted into electrical signals by generating electric charges with photoelectric conversion elements such as photodiodes in accordance with the energy of the converted and irradiated electromagnetic waves. Yes. In the present invention, the detection element in the direct type radiographic imaging apparatus and the photoelectric conversion element in the indirect type radiographic imaging apparatus are collectively referred to as a radiation detection element.

  This type of radiographic image capturing apparatus is known as an FPD (Flat Panel Detector), and is conventionally configured as a so-called dedicated machine integrally formed with a support base or the like (see, for example, Patent Document 1). In recent years, a portable radiographic imaging apparatus in which a radiation detection element or the like is housed in a housing has been developed and put into practical use (see, for example, Patent Documents 2 and 3).

  In such a radiographic imaging apparatus, it may not always be easy to construct an interface between the radiographic imaging apparatus and a radiation generation apparatus that irradiates radiation. In some cases, it is convenient that the radiation imaging apparatus itself is configured to be able to detect the start and end of radiation irradiation without obtaining from the external device.

  Therefore, in the inventions described in Patent Document 4 and Patent Document 5, for example, as shown in FIG. 7 and the like to be described later, when radiation irradiation to the radiation image capturing apparatus is started and charges are generated in each radiation detection element 7, By utilizing the fact that the electric charge flows out from each radiation detection element 7 to the bias line 9 connected to each radiation detection element 7 and the current flowing through the bias line 9 increases, the amount of radiation is increased based on the increase or decrease in the current value. It has been proposed to detect the start of irradiation.

  By the way, when the radiation detecting element 7 is irradiated with radiation, electric charges are generated therein, and the charge amount of the generated charges changes according to the radiation dose. That is, it can be converted into image data) and read out. However, on the other hand, in the radiation detection element 7, even when the radiation imaging apparatus is not irradiated with radiation, electron-hole pairs (that is, so-called dark charges) are generated inside the radiation detection element 7 by thermal excitation caused by heat of the radiation detection element 7 itself. ) Always occurs.

  Therefore, for example, in the radiographic imaging device described in Patent Literature 5, when detecting the current flowing through the bias line 9 to detect the start of radiation irradiation, etc., a thin film transistor (switching means for each radiation detection element 7) If the thin film transistor (hereinafter referred to as TFT) 8 is turned off, dark charges are accumulated in each radiation detection element 7 during that period, and the charges generated in each radiation detection element 7 due to radiation irradiation, That is, the amount of charges that can be stored as image data in each radiation detection element 7 is reduced.

  Therefore, when detecting the current flowing through the bias line 9 to detect the start of radiation irradiation, etc., for example, as shown in FIG. 25, each of the scanning lines 5 from the scanning drive means 15 (see FIG. 7 described later). Each radiation detection element in which an ON voltage is sequentially applied to the lines L1 to Lx to sequentially turn on the TFTs 8 and extra charges such as dark charges accumulated in the radiation detection elements 7 are discharged to the signal lines 6. 7 may be performed.

JP-A-9-73144 JP 2006-058124 A JP-A-6-342099 US Pat. No. 7,211,803 JP 2009-219538 A

  However, as described above, when the radiation detection element 7 is reset, the current flowing through the bias line 9 is detected to detect the start of radiation irradiation, for example, as shown in FIG. From each radiation detection element 7 connected to the scanning line 5 (in the case of FIG. 26, the line L2 of the scanning line 5) that has been reset when it is detected that radiation irradiation has been started, A part of useful charges generated by the irradiation flows out through the TFT 8 which is in the ON state.

  In this case, as shown in FIG. 27, the image data read from each radiation detection element 7 connected to the line L2 of the scanning line 5 is not reliable. Therefore, for example, the image data is discarded, the line L2 of the scanning line 5 is treated as a so-called line defect, and each radiation detection connected to the lines L1 and L3 of the scanning line 5 adjacent to the line L2 of the scanning line 5 is detected. It is necessary to restore the image data of each radiation detection element 7 connected to the line L2 of the scanning line 5 by interpolating the image data read from the element 7 or the like.

  In addition, in a radiation generator that irradiates radiation imaging equipment, when radiation irradiation starts, the radiation dose does not rise instantaneously and the rise of the radiation dose is slow For example, as shown in FIG. 28, the time when radiation irradiation is actually started and the time when the radiation image capturing apparatus detects the start of radiation irradiation are shifted, and a plurality of scanning lines 5 (in the case of FIG. 28). A part of useful charges generated by radiation irradiation flows out from the radiation detection elements 7 connected to the lines L2 to L4) of the scanning line 5 through the TFT 8 which is in the ON state.

  In such a case, if the lines L2 to L4 of the scanning line 5 are handled as line defects in the same manner as described above, the line defects are formed into a plurality of adjacent lines L2 to L4 of the scanning line 5, as shown in FIG. It will appear continuously. Then, for these continuous line defects, for example, the image data is restored by interpolating with the image data read from each radiation detection element 7 connected to the lines L1 and L5 of the scanning line 5, for example. .

  However, for example, when a radiographic image captured by a radiographic image capturing apparatus is used for medical diagnosis or the like, if the image data is discarded as described above, a lesion is captured in each discarded image data. Even if it is done, such information is also destroyed. Even if the image data is restored by interpolating with surrounding image data or the like, the information on the lesion is not restored, and thus the information on the lesion may be lost. As the number of scanning lines 5 that continuously become line defects increases, there is a higher possibility that the lesion information is lost from the image data.

  The present invention has been made in view of the above-described problems, and the apparatus itself can detect the start of radiation irradiation and the like, and in one of the useful charges at the start of radiation irradiation in subsequent image processing. It is an object of the present invention to provide a radiographic image capturing apparatus capable of acquiring image data so that image data lost in a part can be effectively restored. It is another object of the present invention to provide a radiographic image capturing apparatus and a radiographic image processing apparatus that can effectively restore image data based on the image data acquired as described above.

In order to solve the above-described problem, the radiographic imaging device of the present invention includes
A plurality of scanning lines and a plurality of signal lines arranged so as to intersect with each other; a plurality of radiation detecting elements arranged in a two-dimensional manner in each region partitioned by the plurality of scanning lines and the plurality of signal lines; ,
When an off voltage is applied to the connected scanning line, which is arranged for each of the radiation detecting elements, it is turned off, holds charges generated in the radiation detecting element, and an on voltage is applied to the connected scanning line. A switching means that is turned on and emits the charge from the radiation detection element;
Scan driving means comprising: a gate driver that switches a voltage applied to the switch means via the scanning line between an on voltage and an off voltage; and a power supply circuit that supplies the on voltage and the off voltage to the gate driver. When,
Current detection means for detecting current flowing in the device;
Storage means for storing image data read from each of the radiation detection elements;
Prior to radiographic imaging, the scanning drive means sequentially applies an on-voltage to each scanning line and performs a readout process of reading out the image data from each radiation detection element to obtain the image data for each radiation detection element. When it is detected that radiation irradiation has been started based on the value of the current stored in the storage means and output from the current detection means, the reading process of the image data from each radiation detection element is stopped. The scan driving means applies an off voltage to each scanning line, and shifts to a charge accumulation mode for accumulating charges generated in each radiation detection element by irradiation with radiation. After the irradiation is completed, an on-voltage is sequentially applied again from the scanning drive means to the scanning lines, and the image from each radiation detecting element is again applied. And a control means for saving said performing read processing of data the image data for each radiation detection element in the storage means,
It is characterized by providing.

The radiographic image processing apparatus of the present invention is
A radiographic image processing apparatus that restores the image data based on at least the image data transmitted from the radiographic image capturing apparatus of the present invention,
The scanning line to which an on-voltage was applied immediately before or after the start of radiation irradiation in the readout process before the radiographic image capturing is included, and a predetermined voltage to which the on-voltage was applied before the time For each of the radiation detection elements connected to the number of the scanning lines, the image data read in the readout process before the radiographic image capturing and the readout process after the radiation irradiation is completed are read out. The image data of the radiation detection element is restored based on the image data thus obtained.

Furthermore, the radiation image processing apparatus of the present invention is
A radiographic image processing apparatus that restores the image data based on at least the image data transmitted from the radiographic image capturing apparatus of the present invention,
Of the image data read out in the read-out process after the radiation irradiation is completed, the on-voltage is detected at or just before the start of the radiation irradiation in the read-out process before the radiographic image capturing. Analyzing the image data read from each radiation detecting element connected to each scanning line including the scanning line to which the image data has been applied, and determining a range of the scanning line for restoring the image data And about each said radiation detection element connected to the said scanning line in the determined said range, after completion | finish of irradiation of the said image data read by the read-out process before the radiographic image imaging, and the said radiation The image data of the radiation detection element is restored based on the image data read out in the reading process.

Furthermore, the radiographic image processing apparatus of the present invention is
A radiographic image processing apparatus that restores the image data based on at least the image data transmitted from the radiographic image capturing apparatus of the present invention,
Each of the image data read out in the read-out process before radiographic image capturing includes each of the scanning lines to which an on-voltage has been applied at the time of detecting the start of radiation irradiation or just before that. Analyzing the image data read from each of the radiation detection elements connected to the scanning line, determining a range of the scanning line for repairing the image data, and determining the scanning line within the determined range. For each of the connected radiation detection elements, the image data read in the read process before radiographic imaging, and the image data read in the read process after the radiation irradiation ends Based on the above, the image data of the radiation detecting element is restored.

Furthermore, the radiographic image processing apparatus of the present invention is
The above-mentioned book in which the control means analyzes the value of the current output from the current detection means to determine the scanning line to which the on-voltage is applied at the time when radiation irradiation is actually started or immediately after that. A radiographic image processing apparatus for repairing the image data based on at least the image data transmitted from the radiographic image processing apparatus of the invention,
A range of the scanning line for repairing the image data is determined based on the information on the scanning line transmitted from the radiographic imaging device, and each of the radiations connected to the scanning line within the determined range. For the detection element, the radiation detection is performed based on the image data read in the read process before the radiographic image capturing and the image data read in the read process after the irradiation of the radiation is completed. The image data of the element is restored.

Furthermore, the radiographic image processing apparatus of the present invention is
A radiographic image processing apparatus that restores the image data based on at least the image data transmitted from the radiographic image processing apparatus of the present invention,
Analyzing the value of the current output from the current detection means transmitted from the radiographic imaging device, the on-voltage is applied at or immediately after the start of radiation irradiation actually A scan line is determined to determine a range of the scan line for repairing the image data, and for each of the radiation detection elements connected to the scan line within the determined range, read processing before radiographic imaging The image data of the radiation detection element is restored based on the image data read in step (a) and the image data read in the read process after the radiation irradiation is completed. .

  According to the radiographic imaging apparatus of the system of the present invention, the apparatus itself detects the start of radiation irradiation and the like by detecting the current flowing through the wiring in the apparatus such as a bias line by providing a current detection means. It becomes possible.

  In addition, as in the conventional example described above, instead of waiting for the start of radiation irradiation while performing reset processing of each radiation detection element before radiographic imaging, the radiation data is read while performing image data readout processing before radiographic imaging. Wait for the start of irradiation. Then, not only the readout process after radiographic imaging (that is, the so-called main image readout process) but also each image data read out by the readout process before radiographic imaging is stored in the storage means.

  Further, when it is detected that radiation irradiation has started, the reading process of image data before radiographic image capturing is stopped, and the mode shifts to the charge accumulation mode. Therefore, even if the time when radiation irradiation is actually started on the radiographic imaging device and the time when the start of radiation irradiation is deviated, an on-voltage is applied between them to read out image data. It is possible to reduce the number of scanning lines to be processed. Therefore, the number of each radiation detection element whose image data is restored as described above can be reduced.

  In addition, according to the radiographic image capturing apparatus and radiographic image processing apparatus of the system of the present invention, as described above, in the process of restoring the image data read in the read process after radiographic image capturing, the radiation It is possible to restore the image data that is the main image by using the image data read in the reading process before image capturing.

  For this reason, the time at which radiation irradiation is actually started on the radiographic imaging apparatus deviates from the time at which it is detected that radiation irradiation has started, and an on-voltage is applied to the scanning line while radiation is being irradiated. Even if the image data is read out by being applied, the scanning line to which the on-voltage is applied while radiation is being applied is not treated as a line defect as in the conventional example, and the image read during that time is read. Using the data, it is possible to accurately restore the image data read in the reading process after radiographic imaging.

  Therefore, when a radiographic image taken by a radiographic imaging device is used for medical diagnosis or the like, information on a lesion that has been lost when a line defect is used restores image data as described above. Therefore, it is not lost and remains in the radiographic image, so that a doctor or the like can accurately diagnose the lesion by looking at the radiographic image.

It is a perspective view which shows the radiographic imaging apparatus which concerns on this embodiment. It is sectional drawing which follows the XX line in FIG. It is a top view which shows the structure of a board | substrate. It is an enlarged view which shows the structure of the radiation detection element, TFT, etc. which were formed in the small area | region on the board | substrate of FIG. It is sectional drawing which follows the YY 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 block diagram showing the equivalent circuit of a radiographic imaging apparatus. It is a block diagram showing the equivalent circuit about 1 pixel which comprises a detection part. It is an equivalent circuit diagram showing the structure of the structure of an electric current detection means. 6 is a timing chart showing charge reset switches, pulse signals, and TFT on / off timings in image data read processing. It is a graph showing the change of the voltage value etc. in a correlated double sampling circuit. 6 is a timing chart illustrating timings at which an on-voltage is sequentially applied to each scanning line during image data read processing. It is a timing chart showing repeating reading processing of image data from each radiation detecting element for every frame in reading processing before radiographic image photography. It is a graph showing the example of the time transition of the voltage value output from an electric current detection means. 6 is a timing chart illustrating an example of timing for applying an ON voltage to each scanning line in a readout process before radiographic imaging, a charge accumulation mode, and a readout process after radiographic imaging. 12 is a timing chart showing another example of timing for applying an ON voltage to each scanning line in a readout process before radiographic image capture, a charge accumulation mode, and a read process after radiographic image capture. FIG. 16 is a timing chart showing the timing when the processing sequence from the offset correction value reading process to the reading process of image data after radiographic imaging is repeated in the case of FIG. 15. FIG. 17 is a timing chart showing the timing when the processing sequence from the offset correction value reading process to the reading process of image data after radiographic imaging is repeated in the case of FIG. 16. It is a block diagram showing the structure of a radiographic image processing apparatus. It is a graph which shows the example which plotted the average value for every scanning line of true image data D ^* in order of the line number of the scanning line. It is a graph which shows the example which plotted the average value for every scanning line of true image data d ^* in order of the line number of the scanning line. It is a figure explaining the relationship between the electric charge discharge | released from a radiation detection element, each electric charge leaked from another radiation detection element, and the read image data. It is a block diagram showing the equivalent circuit of the radiographic imaging apparatus at the time of comprising so that an electric current detection means may be connected to a scanning line etc. It is a block diagram showing the equivalent circuit at the time of providing a current detection means in the wiring of a scanning drive means. It is a timing chart which shows the timing which applies an ON voltage to each scanning line at the time of the reset process of each radiation detection element. It is a timing chart explaining that a part of electric charge generated by irradiation of radiation flows out through a TFT which is in an ON state by a reset process. It is a figure showing the scanning line treated as a line defect. It is a timing chart explaining that a part of useful electric charge flows out from each radiation detection element connected to a plurality of scanning lines by shifting the actual radiation irradiation start time and the time of detecting the start of radiation irradiation. It is a figure showing the example of the line defect which appeared continuously in the some line which a scanning line adjoins.

  Embodiments of a radiographic image capturing apparatus and a radiographic image processing apparatus according to the present invention will be described below with reference to the drawings.

  In the following description, the radiographic imaging device is a so-called indirect radiographic imaging device that includes a scintillator or the like and converts the irradiated radiation into electromagnetic waves of other wavelengths such as visible light to obtain an electrical signal. As will be described, the present invention can also be applied to a direct radiographic imaging apparatus. Although the case where the radiographic image capturing apparatus is portable will be described, the present invention is also applicable to a dedicated radiographic image capturing apparatus formed integrally with a support base or the like.

  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 XX of FIG. In this embodiment, the radiographic image capturing apparatus 1 is configured as a portable (that is, so-called cassette type) 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. ing.

  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 in which the housing 2 is a so-called lunch box type formed by the frame plate 2A and the back plate 2B. However, the housing 2 is integrally formed in a rectangular tube shape. It is also possible to use a so-called monocoque type.

  As shown in FIG. 1, the side surface of the housing 2 is opened and closed for replacement of a power switch 36, an indicator 37 composed of LEDs and the like, and a battery 41 (not shown) (see FIG. 7 described later). A possible lid member 38 and the like are arranged. In the present embodiment, the antenna device 39 is embedded in the side surface of the lid member 38.

  The installation position of the antenna device 39 is not limited to the side surface portion of the lid member 38, and the antenna device 39 can be installed at an arbitrary position of the radiographic image capturing apparatus 1. The number of antenna devices 39 to be installed is not limited to one, and a plurality of antenna devices 39 may be provided. Furthermore, it is also possible to configure data and signals to be transmitted and received with an external device in a wired manner. In that case, for example, a connection terminal for connecting by inserting a cable or the like is a radiographic image. Provided on the side surface of the photographing apparatus 1 or the like.

  As shown in FIG. 2, a base 31 is disposed inside the housing 2 via a lead thin plate (not shown) on the lower side of the substrate 4, and electronic components 32 and the like are disposed on the base 31. The PCB substrate 33, the buffer member 34, and the like are attached. In the present embodiment, a glass substrate 35 for protecting the substrate 4 and the radiation incident surface R of the scintillator 3 is disposed.

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

  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 small region r defined by the plurality of scanning lines 5 and the plurality of signal lines 6 on the surface 4 a of the substrate 4, radiation detection elements 7 are respectively provided.

  Thus, the entire region r in which a plurality of radiation detection elements 7 arranged in a two-dimensional manner are provided in each small region r partitioned by the scanning line 5 and the signal line 6, that is, shown by a one-dot chain line in FIG. The region is a detection unit P.

  In the present embodiment, a photodiode is used as the radiation detection element 7, but other than this, for example, a phototransistor or the like can also be used. Each radiation detection element 7 is connected to the source electrode 8s of the TFT 8 serving as a switch means, as shown in the enlarged views of FIGS. The drain electrode 8 d of the TFT 8 is connected to the signal line 6.

  The TFT 8 is turned on when a turn-on voltage is applied to the connected scanning line 5 by the scanning drive means 15 described later and applied to the gate electrode 8g, and is generated and accumulated in the radiation detection element 7. The charged electric charge is discharged to the signal line 6. The TFT 8 is turned off when the off voltage is applied to the connected scanning line 5 and the off voltage is applied to the gate electrode 8g, and the discharge of the charge from the radiation detecting element 7 to the signal line 6 is stopped. Electric charges generated in the radiation detection element 7 are held and accumulated in the radiation detection element 7.

  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 cross-sectional view taken along line YY 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.

  When radiation enters from the radiation incident surface R of the housing 2 of the radiographic imaging apparatus 1 and is converted into an electromagnetic wave such as visible light by the scintillator 3, and the converted electromagnetic wave is irradiated from above in the figure, the electromagnetic wave is detected by radiation. The electron hole pair is generated in the i layer 76 by reaching the i layer 76 of the element 7. In this way, the radiation detection element 7 converts the electromagnetic waves irradiated from the scintillator 3 into electric charges.

  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. In the present embodiment, the radiation detection element 7 is formed as described above.

  The order of stacking the p layer 77, the i layer 76, and the n layer 75 may be reversed. Further, in the present embodiment, a case where a so-called pin-type radiation detection element formed by sequentially stacking the p layer 77, the i layer 76, and the n layer 75 as described above is used as the radiation detection element 7. However, for example, it may be configured by other types of radiation detection elements such as a MIS (Metal-Insulator-Semiconductor) type, and is not limited.

A bias line 9 for applying a 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.

  In this embodiment, as shown in FIG. 3, each scanning line 5, each signal line 6, and connection 10 of the bias line 9 are input / output terminals (also referred to as pads) provided near the edge of the substrate 4. 11 is connected. As shown in FIG. 6, each input / output terminal 11 has a COF (Chip On Film) 12 in which a chip such as an IC 12a constituting a gate driver 15b, which will be described later, is incorporated on an anisotropic conductive adhesive film (Anisotropic adhesive film). It is connected via an anisotropic conductive adhesive material 13 such as Conductive Film or Anisotropic 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. In FIG. 6, illustration of the electronic component 32 and the like is omitted.

  Here, the circuit configuration of the radiation image capturing apparatus 1 will be described. FIG. 7 is a block diagram showing an equivalent circuit of the radiographic imaging apparatus 1 according to the present embodiment, and FIG. 8 is a block diagram showing an equivalent circuit for one pixel constituting the detection unit P.

  As described above, each radiation detection element 7 of the detection unit P of the substrate 4 has the bias line 9 connected to the second electrode 78, and each bias line 9 is bound to the connection 10 to the bias power supply 14. It is connected. The bias power supply 14 applies a bias voltage to the second electrode 78 of each radiation detection element 7 via the connection 10 and each bias line 9.

  In the present embodiment, as can be seen from the fact that the bias line 9 is connected to the p-layer 77 side (see FIG. 5) of the radiation detection element 7 via the second electrode 78, A voltage lower than the voltage applied to the first electrode 74 side of the radiation detection element 7 (that is, a so-called reverse bias voltage) is applied to the second electrode 78 of the radiation detection element 7 as a bias voltage via the bias line 9. Yes.

  In the present embodiment, the bias power source 14 is connected to a control unit 22 described later, and the control unit varies the bias voltage applied from the bias power source 14 to each radiation detection element 7 as necessary. Yes.

  In this embodiment, the connection 10 of the bias line 9 is provided with a current detection means 43 that detects a current flowing through the connection 10 (bias line 9).

  7 and FIG. 8 and FIG. 3 described above show the case where each bias line 9 is bound to one connection 10. In this case, the current detection means 43 is connected to one connection 10. However, there are cases where each bias line 9 is configured to be bound to a plurality of connections 10. In that case, the current detection means 43 can be provided in each connection 10, or the current detection means 43 can be provided in some of the plurality of connections 10. Is possible.

  Here, the configuration of the current detection means 43 will be described. In the present embodiment, the current detection means 43 is provided at a connection portion between the connection 10 of the bias line 9 and the bias power supply 14, and detects the current flowing through the connection 10 of the bias line 9 by converting it into a voltage value V. It is supposed to be.

  Specifically, as shown in FIG. 9, the current detection unit 43 is a resistor having a predetermined resistance value connected in series to the connection 10 of the bias wiring 9 that connects the bias power supply 14 and each radiation detection element 7. 43 a, a diode 43 b connected in parallel thereto, and a differential amplifier 43 c that measures the voltage V between both terminals of the resistor 43 a and outputs the voltage V to the control means 22.

  Then, the current detection means 43 measures the voltage V between both terminals of the resistor 43a by the differential amplifier 43c, and converts the current flowing through the resistor 43a, that is, the current flowing through the connection 10 of the bias line 9 into a voltage value V. Then, it is detected and output to the control means 22.

  As the resistor 43a provided in the current detection means 43, a resistor having a resistance value capable of converting the current flowing through the connection 10 into an appropriate voltage value V is used. Moreover, the detection accuracy in the case of a low dose is improved by connecting the diode 42d in parallel with the resistor 43a. It is also possible to connect only one of the resistor 43a and the diode 43b in series with the wiring and measure the voltage V between the two terminals with the differential amplifier 43c.

  In the present embodiment, the current detection unit 43 is provided with a switch 43d for short-circuiting both terminals of the resistor 43a when it is not necessary to detect the current flowing through the connection 10 of the bias line 9. ing.

  Further, power is supplied from the power supply means 44 to the differential amplifier 43c. When the current detection means 43 detects a current, power is supplied from the power supply means 44 to the differential amplifier 43c. When the short circuit of the switch 43d is released and the current detection means 43 is activated and no current is detected, both terminals of the resistor 43a are short-circuited by the switch 43d and the difference from the power supply means 44 is detected. The supply of power to the dynamic amplifier 43c is stopped, and the activation of the current detection means 43 is stopped.

  In the present embodiment, the current detection unit 43 is configured to detect the current flowing through the bias line 9 and the connection 10 by converting the current into the voltage value V as described above. It is also possible to configure so as to detect the current value itself, for example, by detecting the magnetism generated around the.

  As shown in FIGS. 7 and 8, the first electrode 74 of each radiation detection element 7 is connected to the source electrode 8s (denoted as S in FIGS. 7 and 8) of the TFT 8, and each TFT 8 The gate electrode 8g (denoted as G in FIGS. 7 and 8) is connected to each line L1 to Lx of each scanning line 5 extending from a gate driver 15b of the scanning driving means 15 described later. . Further, the drain electrode 8 d (denoted as D in FIGS. 7 and 8) of each TFT 8 is connected to each signal line 6.

  In this embodiment, the scanning drive unit 15 includes a power supply circuit 15a and a gate driver 15b, and an on-voltage applied to the gate electrode 8g of the TFT 8 via each scanning line 5 connected to the gate driver 15b. The off voltage is controlled. In the present embodiment, the power supply circuit 15a supplies an on voltage and an off voltage to be applied to the gate electrode 8g of the TFT 8 via each scanning line 5 to the gate driver 15b.

  Each signal line 6 is connected to each readout circuit 17 formed in the readout IC 16. In the present embodiment, the read IC 16 is provided with a predetermined number of read circuits 17, and by providing a plurality of read ICs 16, the read 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, an analog multiplexer 21, and an A / D converter 20. 7 and 8, the correlated double sampling circuit 19 is represented as CDS. In FIG. 8, the analog multiplexer 21 is omitted.

In the present embodiment, the amplifier circuit 18 is configured by a charge amplifier circuit, and is configured by connecting a capacitor 18b and a charge reset switch 18c in parallel to the operational amplifier 18a and the operational amplifier 18a. Further, the signal line 6 is connected to the inverting input terminal on the input side of the operational amplifier 18 a of the amplifier circuit 18, and the reference potential V ₀ is applied to the non-inverting input terminal on the input side of the amplifier circuit 18. ing. Note that the reference potential V ₀ is set to an appropriate value, and in this embodiment, for example, 0 [V] is applied.

  The charge reset switch 18 c of the amplifier circuit 18 is connected to the control means 22, and is turned on / off by the control means 22. When the charge reset switch 18c is off and the TFT 8 of the radiation detection element 7 is turned on (that is, when an on-voltage is applied to the gate electrode 8g of the TFT 8 via the scanning line 5), the radiation The electric charge discharged from the detection element 7 flows into the capacitor 18b and is accumulated, and a voltage value corresponding to the accumulated electric charge is output from the output terminal of the operational amplifier 18a.

  In this way, the amplifier circuit 18 outputs a voltage in accordance with the amount of charge output from each radiation detection element 7, converts the charge voltage, and amplifies it. Further, by turning on the charge reset switch 18c, the input side and the output side of the amplifier circuit 18 can be short-circuited, and the charge accumulated in the capacitor 18b can be discharged to reset the amplifier circuit 18. It has become.

  Note that the amplifier circuit 18 may be configured to output a current in accordance with the charge output from the radiation detection element 7. Further, as shown in FIG. 8, power is supplied from the power supply unit 42 to the amplifier circuit 18. In FIG. 7, the power supply unit 42 is not shown.

  A correlated double sampling circuit (CDS) 19 is connected to the output side of the amplifier circuit 18. In this embodiment, the correlated double sampling circuit 19 has a sample and hold function. The sample and hold function in the correlated double sampling circuit 19 is turned on / off by a pulse signal transmitted from the control means 22. To be controlled.

  That is, for example, in the image data reading process, as shown in FIG. 10, first, the charge reset switch 18c of the amplifier circuit 18 of each reading circuit 17 is controlled to be turned off. At that time, the so-called kTC noise is generated at the moment when the charge reset switch 18c is turned off, and the charge caused by the kTC noise accumulates in the capacitor 18b of the amplifier circuit 18.

Therefore, as shown in FIG. 11, the voltage value output from the amplifier circuit 18 starts from the above-described reference potential V ₀ at the moment when the charge reset switch 18c is turned off (indicated as “18coff” in FIG. 11). It changes by the amount of electric charge caused by kTC noise and changes to a voltage value Vin. At this stage, the control means 22 transmits the first pulse signal Sp1 to the correlated double sampling circuit 19 as shown in FIG. 10, and at that time (shown as “CDS hold” (left side in FIG. 11)). Thus, the voltage value Vin output from the amplifier circuit 18 is held.

  Subsequently, as shown in FIG. 10, an on-voltage is applied to one scanning line 5 (for example, the line Ln of the scanning line 5) from the gate driver 15b of the scanning driving means 15, and a gate electrode 8g is applied to the scanning line 5. When the TFTs 8 connected to each other are turned on (refer to FIG. 10; indicated as “TFTon” in FIG. 11), the charges accumulated from the radiation detecting elements 7 connected to these TFTs 8 are applied to the signal lines 6. As shown in FIG. 11, the voltage value output from the amplifier circuit 18 rises according to the amount of charge stored in the capacitor 18b.

  Then, after a predetermined time has elapsed, the control means 22 switches the on-voltage applied to the scanning line 5 from the gate driver 15b to the off-voltage and turns the gate electrode 8g on the scanning line 5 as shown in FIG. Is turned off (indicated as “TFToff” in FIG. 11), and at this stage, the second pulse signal Sp2 is transmitted to each correlated double sampling circuit 19, and at that time, the amplifier circuit 18 The output voltage value Vfi is held (displayed as “CDS hold” (right side) in FIG. 11).

  When each correlated double sampling circuit 19 holds the voltage value Vfi with the second pulse signal Sp2, the voltage difference Vfi-Vin is calculated, and the calculated difference Vfi-Vin is downstream as analog value image data. It is designed to output.

  The image data of each radiation detection element 7 output from the correlated double sampling circuit 19 is transmitted to the analog multiplexer 21 and sequentially transmitted from the analog multiplexer 21 to the A / D converter 20. Then, the A / D converter 20 sequentially converts the image data into digital values, which are output to the storage means 40 and sequentially stored.

  Then, in the image data reading process, the control unit 22 sequentially applies an on-voltage to each of the lines L1 to Lx of the scanning line 5 from the scanning driving unit 15 as shown in FIG. In this way, image data is read from each radiation detection element 7 connected to each line L1 to Lx of the scanning line 5, respectively.

  The control means 22 includes a CPU (Central Processing Unit), a ROM (Read Only Memory), a RAM (Random Access Memory), an input / output interface connected to the bus, an FPGA (Field Programmable Gate Array), or the like (not shown). It is configured. It may be configured by a dedicated control circuit. And the control means 22 controls operation | movement etc. of each member of the radiographic imaging apparatus 1. Further, as shown in FIG. 7 and the like, the control means 22 is connected with a storage means 40 constituted by a DRAM (Dynamic RAM) or the like.

  In the present embodiment, the control unit 22 is connected to the antenna device 39 described above, and each function of the detection unit P, the scanning drive unit 15, the readout circuit 17, the storage unit 40, the bias power source 14, and the like. A battery 41 for supplying power to the unit is connected. The battery 41 is provided with a connection terminal 42 that connects the charging device and the battery 41 when the battery 41 is charged by supplying power from a charging device (not shown).

  Hereinafter, the reading process of the image data D from each radiation detection element 7 after the completion of radiation irradiation from each process before radiographic imaging in the radiographic imaging apparatus 1 will be described.

  In the present embodiment, the control means 22 is configured to detect a radiographic image by pressing a power switch 36 (see FIG. 1) of the radiographic image capturing apparatus 1 or transmitting an activation signal from an external computer or the like before radiographic image capturing. When the imaging apparatus 1 is activated or when the radiographic imaging apparatus 1 is transitioned from a so-called sleep state to an awakening state, a trigger signal is transmitted to the scanning driving means 15 to read out image data before radiographic imaging. Is supposed to do.

  In order to distinguish the image data read in the readout process before radiographic image capturing from the image data read out in the readout process after completion of radiation irradiation (to be described later) (that is, so-called main image readout process), image data is used. d. Further, image data read in the reading process after the radiation irradiation is completed is referred to as image data D.

  Further, it is also possible to perform a read process of the image data d before radiographic image capturing after the reset process (see FIG. 25) of each of the radiation detection elements 7 described above is repeatedly performed, for example, a predetermined number of times.

  In the present embodiment, all of the radiation detection elements 7 to be read from the image data d among the radiation detection elements 7 for one surface arranged in a two-dimensional manner on the detection unit P (see FIGS. 3 and 7). Assuming that the period for reading the image data d from the frame is one frame, the control means 22 in the reading process of the image data d before radiographic image capturing, as shown in FIG. The reading process of the image data d from is repeatedly performed.

  The control unit 22 stores the image data d read out for each radiation detection element in the storage unit 40.

  In this case, it is not necessary to store all the image data d read for each frame after the reading process is started. There are also restrictions such as the storage capacity of the storage means 40. Therefore, in the present embodiment, the number of frames for storing the image data d in the storage unit 40 is set in advance.

  Then, the control means 22 repeats the reading process of the image data d from each radiation detection element 7 as described above, and the image data d of each radiation detection element 7 for the number of frames set in advance is stored in the storage means. When the data is stored in 40, the image data d of each subsequent frame is sequentially overwritten and stored on the image data d of the past frame in order from the frame in which the image data d is first stored. Yes.

  Note that, as will be described later, using the image data d read in a frame prior to the frame in which the radiation irradiation was detected, an offset amount superimposed on the image data d (that is, an offset correction value o described later) is obtained. When not configured to calculate, the number of frames for storing the image data d in the storage means 40 may be one frame.

  In that case, for example, when the image data d is stored in the storage means 40 until the last line Lx of the scanning line 5 in a certain frame, the control means 22 is connected to the first line L1 of the scanning line 5 in the next frame. Each image data d read from each radiation detection element 7 is stored as each image data d read from each radiation detection element 7 connected to the line L1 of the scanning line 5 in the previous frame. The address of the storage means 40 is overwritten and stored, and this processing is performed each time the on-voltage is applied to each line L of the scanning line 5 and the image data d is read.

  On the other hand, the control unit 22 repeatedly performs the reading process of the image data d from each of the radiation detection elements 7 before radiographic imaging as described above, and outputs it from the current detection unit 43 described above as a separate process. The voltage value V to be monitored is monitored.

  The voltage value V output from the current detection means 43 changes, for example, as shown in FIG. 14 corresponding to the increase or decrease of the current flowing through the connection 10 of the bias line 9. That is, at the time ta before the radiation image capturing apparatus 1 is irradiated with radiation, the current flowing through the bias line 9 flows into the connection 10 as dark charges are generated in each radiation detection element 7, so that the radiation is transmitted. Even if it is not irradiated, a very small amount of current flows in the connection 10 of the bias line 9, and the current detection means 43 outputs a voltage value Va corresponding to the small amount but not 0.

  Then, when radiation irradiation is started on the radiographic imaging apparatus 1 (see time tb in FIG. 14), as described above, charges (that is, electron positives) are generated in the i layer 76 (see FIG. 5) of each radiation detection element 7. A pair of holes) is generated, and the current flowing through the bias line 9 and the connection 10 is correspondingly increased.

  Therefore, in the present embodiment, the control unit 22 detects that the radiation irradiation has started by detecting that the voltage value V output from the current detection unit 43 has started to increase greatly. ing.

  The detection of the start of radiation irradiation may be configured to detect that radiation irradiation has started at time tc when the voltage value V output from the current detection means 43 exceeds a preset threshold value Vth. It is also possible to detect that radiation irradiation is started at time td when the time differential value of the voltage value V exceeds a preset threshold value.

  When the irradiation of radiation from the radiation generating device is completed, generation of new electron-hole pairs in each radiation detecting element 7 is stopped and current corresponding thereto does not flow in the bias line 9. Therefore, as shown at time te in FIG. 14, the voltage value V output from the current detection means 43 starts to decrease.

  In view of this, for example, it is possible to detect that the voltage value V output from the current detection unit 43 has decreased, and to detect that radiation irradiation has ended. In this case, the detection of the end of radiation irradiation may be configured to detect that the radiation irradiation has ended at time tf when the voltage value V falls below the threshold value Vth described above. It may be configured to detect that radiation irradiation has been completed at time tg when the value exceeds a predetermined negative value threshold value to the more negative side.

  It is also possible to configure the control means 22 to detect the completion of radiation irradiation in this way, and to detect when radiation irradiation has started as described above (for example, Assuming that radiation irradiation has ended when a predetermined time set in advance from time tc) has elapsed, it is also possible to proceed to read processing of image data D after radiation irradiation described below has ended. It is.

  When the control means 22 detects that radiation irradiation has been started based on the voltage value V corresponding to the current flowing through the connection 10 of the bias line 9 output from the current detection means 43 as described above, FIG. As shown in the figure, the reading process of the image data d from each radiation detection element 7 before radiographic image capturing is stopped, and an off voltage is applied to each line L1 to Lx of the scanning line 5 from the scanning driving means 15. Yes.

  In this way, by applying an off voltage to each of the lines L1 to Lx of the scanning line 5, the charge generated in each radiation detection element 7 due to radiation irradiation is accumulated in each radiation detection element 7, Transition to charge accumulation mode.

  In FIG. 15, radiation irradiation is performed at or immediately after the ON voltage is applied to the line Ln of the scanning line 5 (that is, before the ON voltage is applied to the next line Ln + 1 of the scanning line 5). The case where it is detected that it has started is shown.

  In fact, the radiation imaging apparatus 1 shows a case where radiation irradiation is started at or just before the on-voltage is applied to the line Ln-2 of the scanning line 5. At this point in time, as described above, the radiation image capturing apparatus 1 itself cannot detect the point in time when the actual radiation irradiation is started.

  As described above, the control means 22 irradiates the radiation when a predetermined time elapses from the time when it is detected that the radiation irradiation is started, or when it is detected that the radiation irradiation has ended. The reading process of the image data D after ending is started. In the following, for easy comparison with the reading process of the image data d before the radiographic image capturing, the reading process of the image data D after the radiation irradiation is completed is referred to as the reading process of the image data D after the radiographic image capturing. That's it.

  In the present embodiment, in the reading process of the image data D after radiographic imaging, the scanning driving unit 15 applies an applied voltage after applying an on-voltage to each of the lines L1 to Lx of the scanning line 5 during the reading process. The time until switching to the off-voltage (hereinafter referred to as the on-time, ie, the time during which the on-voltage is applied in the timing chart at the bottom of FIG. 10) is the same as the reading process of the image data d before radiographic imaging. It is supposed to be.

  Strictly speaking, the ON time for each scanning line 5 in the reading process of the image data d before the radiographic image capturing is set to be the same as the ON time for each scanning line 5 in the reading process of the image data D after the radiographic image capturing. It is configured.

  In this way, if the on-time for each scanning line 5 in the readout process of the image data d before radiographic image capturing is the same as the on-time for each scanning line 5 in the readout process of the image data D after radiographic image capture, The on-voltage is applied to each of the lines L1 to Lx of the scanning line 5 from the gate driver 15b of the scanning driving unit 15 by the reading process of the image data d before the radiographic image capturing and the read processing of the image data D after the radiographic image capturing. It is not necessary to change the on-time at that time, and at least the on-time can be configured to repeat only the same processing in both reading processes.

  For example, the ON time for each scanning line 5 in the reading process of the image data d before the radiographic image capturing is set to be longer than the ON time for each scanning line 5 in the reading process of the image data D after the radiographic image capturing. This configuration has the following advantages.

  That is, as described above, when the time when radiation irradiation is actually started is different from the time when the control means 22 detects that radiation irradiation has started, the time interval between these times is the same. In addition, if the on-time is short, the on-voltage is successively applied to each scanning line 5 during the time interval, so that the number of scanning lines 5 to which the on-voltage is applied increases, and image data will be described later. The number of scanning lines 5 that must repair D increases.

  However, as the on-voltage is increased as described above, the number of scanning lines 5 to which the on-voltage is applied during the same time interval is reduced, so that the image data D must be restored. There is an advantage that the number can be reduced.

  In the present embodiment, as shown in FIG. 15, in the readout process after radiographic imaging, the control unit 22 detects the start of radiation irradiation in the readout process before radiographic imaging or immediately before it. Next, the scanning line 5 to which the on-voltage is to be applied next (the line Ln + 1 of the scanning line 5 in the example of FIG. 15) to which the on-voltage is applied next to the scanning line 5 (the line Ln of the scanning line 5 in the example of FIG. 15). ), Reading processing of the image data D from each radiation detection element 7 is performed.

  As shown in FIG. 16, in the readout process after radiographic imaging, the on-voltage is sequentially applied in order from the first line L1 of the scanning line 5, and the readout process of the image data D from each radiation detection element 7 is performed. It is also possible to configure it. The advantage of the configuration shown in FIG. 15 will be described when the offset correction value reading process described later is described.

  As shown in FIG. 15, when the readout process after radiographic imaging is started from the line Ln + 1 of the scanning line 5, after reading to the last line Lx of the scanning line 5, the first line L1 of the scanning line 5 is read. Returning to the line Ln of the scanning line 5, the reading process is performed. And the control means 22 preserve | saves the image data D read from each radiation detection element 7 by the read-out process after radiographic imaging in the memory | storage means 40. FIG.

  On the other hand, in the present embodiment, when the control unit 22 finishes the reading process of the image data D after the radiographic image capturing, as shown in FIG. 17, the same timing as the read process of the image data d before the radiographic image capturing is performed again. The on-voltage is sequentially applied to the lines L1 to Lx of the scanning line 5 and the voltage applied to the lines L1 to Lx of the scanning line 5 is switched to the off-voltage to shift to the charge accumulation mode. The offset correction value reading process for reading the offset correction value O is performed by sequentially applying the ON voltage to each of the lines L1 to Lx of the scanning line 5 at the same timing as the reading process of the image data D.

  In this case, the offset correction value reading process is because the offset due to the dark charge that is constantly generated in each radiation detection element 7 is superimposed on the image data D as described above. This is a process for reading out only the offset offset as an offset correction value O. The offset amount depends on the amount of dark charge accumulated in each radiation detection element 7 while each TFT 8 is in the OFF state. The amount of dark charge accumulated is determined when each TFT 8 is in the OFF state. It varies depending on the period of time (hereinafter referred to as the TFT 8 off time).

  Therefore, in order to make the offset amount superimposed on the image data D and the offset correction value O read out by the offset correction value reading process the same size, in the present embodiment, as described above, before radiographic imaging. The offset correction value reading process is performed by repeating the same processing sequence as the reading process of the image data D after the radiographic image capturing from the reading process of the image data d.

  However, in the charge accumulation mode of the offset correction value reading process, the radiation image capturing apparatus 1 is not irradiated with radiation. That is, in the charge accumulation mode in the offset correction value reading process, the radiation image capturing apparatus 1 is left for the same time as the charge accumulation mode before the image data D reading process after the radiographic image capturing.

  If comprised in this way, TFT8 was made into the OFF state in each line L1-Lx of the scanning line 5 from the read-out process of the image data d before radiographic imaging to the read-out process of the image data D after radiographic imaging. The off time is the same as the off time in which the TFT 8 is turned off in each of the lines L1 to Lx of the scanning line 5 in the offset correction value reading process, and the offset amount superimposed on the image data D and the offset correction value O And become the same size.

Therefore, by subtracting the offset correction value O from the image data D, the true image data D ^* corresponding to only the charges (not including the dark charge) generated in each radiation detection element 7 due to radiation irradiation is obtained. Can be obtained.

  As described above, when the offset correction value reading process is performed by repeating the same processing sequence as the reading process of the image data D after the radiographic image capturing from the reading process of the image data d before the radiographic image capturing as it is, After the reading process of the image data D after radiographic imaging, the reading process of the image data d is performed again. In the description here, in order to distinguish from the image data d read out in the read-out process before radiographic image capturing, the image data d is read again after the read-out process of the image data D after radiographic image capturing. The read image data d is referred to as image data da.

  However, the image data d read out in the reading process of the image data d before the radiographic image is used for the restoration process of the image data D described later, but after the reading process of the image data D after the radiographic image is taken. Even if the image data da is read again, the read image data da is not used for the restoration processing of the image data D. If the image data da is read, wasteful power is wasted in each read circuit 17 by the amount that the image data da must be read.

  Therefore, instead of performing the reading process of the image data da after the reading process of the image data D after radiographic imaging, as shown in FIG. 17, each line Ln + 1 to Lx of the scanning line 5 for the same on-time. It is possible to apply a turn-on voltage to L1 to Ln and perform a reset process of each radiation detection element 7. With this configuration, it is not necessary to perform read processing in each read circuit 17, and thus it is possible to prevent wasteful power consumption in each read circuit 17.

  Contrary to the above, the image data D is read out again after the radiographic image reading and the image data da is read out again, and the image data D is used to store the image data D. It can also be configured to correct. With this configuration, it is possible to read the unread portion that could not be read out in the reading process of the image data D as the image data da. For example, the image data da read out for each radiation detection element 7 is It becomes possible to correct the image data D by adding it to the image data D of the radiation detection element 7, and the image quality is improved accordingly.

  On the other hand, the offset correction value reading process is performed a plurality of times to obtain a plurality of offset correction values O for each radiation detection element 7, and for example, an average value of the offset correction values O is calculated and the average value is calculated. It is also possible to configure the offset correction value O of the radiation detection element 7.

  Further, as shown in FIG. 15, the line Ln of the scanning line 5 to which the on-voltage was applied at the time when it was detected that the irradiation of radiation was started or immediately before it was detected in the readout processing after radiographic imaging. If the read processing of the image data D from each radiation detection element 7 is performed from the next line Ln + 1, as shown in FIG. 17, after the read processing after radiographic imaging, the scanning line 5 continues. The on-voltage is sequentially applied from the first line Ln + 1 to the last line Lx, the on-voltage is sequentially applied from the first line L1 to the line Ln of the scanning line 5, and reset processing (or image data reading processing) is performed. It is possible to shift to the charge accumulation mode.

  On the other hand, as shown in FIG. 16, when the ON voltage is sequentially applied from the first line L1 of the scanning line 5 to read out the image data D after radiographic imaging, FIG. As shown, in the subsequent reset process (or image data read process), the ON voltage is sequentially applied from the first line L1 to the line Lx of the scanning line 5 and turned on from the first line L1 to the line Ln of the scanning line 5. A voltage is sequentially applied to perform reset processing (or image data read processing), and the mode shifts to the charge accumulation mode.

  That is, in the case shown in FIG. 18, compared to the case shown in FIG. 17, the number of scanning lines 5 to which the ON voltage is applied in the reset processing (or image data read processing) of each radiation detection element 7 is The number is increased by the first lines L1 to Ln of the scanning line 5. For this reason, the time required for reset processing (or image data reading processing) of each radiation detection element 7 becomes longer, and as a result, the time required for offset correction value reading processing becomes longer.

  However, if each process is performed as shown in FIGS. 15 and 17, the number of scanning lines 5 to which the ON voltage is applied in the reset process (or the image data read process) of each radiation detection element 7. There is an effect that all the processes including the radiographic image capturing and the offset correction value reading process can be performed in a shorter time.

  The control unit 22 stores the offset correction value O read from each radiation detection element 7 in the offset correction value reading process in the storage unit 40. As described above, when an average value or the like of a plurality of offset correction values O is used as the offset correction value O, the average value or the like is calculated and stored in the storage unit 40.

  Note that the offset due to the dark charge is also superimposed on the image data d read from each radiation detection element 7 in the read processing of the image data d before radiographic image capturing. However, since the readout process before radiographic image capture is repeatedly performed for each frame as shown in FIG. 13, there is no charge accumulation mode period shown in FIG.

  Therefore, after the reading process of the image data D after radiographic imaging shown in FIG. 17 is completed, the process from the reset process (or the reading process of the image data) of each radiation detection element 7 to the offset correction value reading process. The off time of the TFT 8 in each of the lines L1 to Lx of the scanning line 5 and the off time of the TFT 8 in each of the lines L1 to Lx of the scanning line 5 between the readout processes before the radiographic image capturing for each frame shown in FIG. Is different from the charge accumulation mode period.

  For this reason, the offset amount superimposed on the image data d read in the reading process before radiographic imaging and the offset correction value O read in the offset correction value reading process are different from each other. Cannot be used for offset correction processing of image data d.

  However, as shown in FIG. 13, the image data d read in each frame before the radiation image capturing apparatus 1 is irradiated with radiation does not depend on the charges due to the irradiation of radiation, but depends only on the accumulated dark charges. Therefore, the image data d read out in each frame before radiation irradiation is read out from when radiation irradiation is actually started until it is detected that radiation irradiation has started. Used as an offset correction value of the image data d (that is, image data d read from each radiation detection element 7 connected to the lines Ln-2 to Ln of the scanning line 5 in the example of FIG. 15). Can do.

  The image data d as an offset correction value in this case is hereinafter referred to as an offset correction value o. Further, the image data d read during the period from when radiation irradiation is actually started until it is detected that radiation irradiation has started is hereinafter referred to as image data read during radiation irradiation. d.

  Therefore, for example, as described above, out of the image data d read out for each frame before radiographic image capturing, before the detection of the start of radiation irradiation remaining in the storage means 40 without being overwritten. It is possible to use the image data d of the frame as an offset correction value o of the image data d read out during radiation irradiation.

  Further, when the image data d of the frame before the detection of the start of radiation irradiation is stored for a plurality of frames and remains, the image data d of each of the frames is stored for each radiation detection element 7. It is also possible to calculate the average value and use each average value as the offset correction value o of the image data d read out during radiation irradiation.

  Further, the offset correction value o of the image data d read during radiation irradiation may be set in advance for each radiation detection element 7. In the following, a case where the offset correction value o is acquired by the radiographic imaging device 1 will be described. However, when the offset correction value o is set in advance, the memory of the radiographic imaging device 1 such as the storage unit 40 or the like An offset correction value o for each radiation detection element 7 is stored in advance in a memory of a radiation image processing apparatus 50 to be described later, and the control means 22 and the radiation image processing apparatus 50 refer to it for a repair process described below. Configured to do.

  Next, the scanning line 5 to which an on-voltage is applied between the time when the radiation imaging apparatus 1 is actually irradiated and the time when it is detected that the irradiation is started (that is, during the irradiation of radiation) ( In the example of FIG. 15, a restoration process based on the image data d of the image data D read from each radiation detection element 7 connected to the lines Ln-2 to Ln) of the scanning line 5 will be described.

  This repair process can be configured to be performed by the radiographic image capturing apparatus 1 itself, that is, the control means 22, and is separate from the radiographic image capturing apparatus 1, for example, a CPU 51 and a ROM 52 as shown in FIG. , A RAM 53, an input / output interface 54 and the like are connected to the bus 55, and a radiation image processing apparatus configured by a computer or the like to which an input means 56 such as a mouse or a keyboard or a storage means 57 such as an HDD (Hard Disk Drive) is connected. It is also possible to configure it to be performed at 50.

  In this case, a predetermined program is stored in the ROM of the radiation image processing apparatus 50, and the radiation image processing apparatus 50 reads out the necessary program, expands it in the work area of the RAM, and executes the above-described repair processing according to the program. Configured to do.

  When the radiographic image processing apparatus 50 is configured to perform the repair process, the radiographic image capturing apparatus 1 has started irradiation of radiation among the image data d read by the read process before radiographic image capturing. The line number of the scanning line 5 to which the on-voltage was applied at or immediately before the detection of each offset d, the offset correction value o, and the start of radiation irradiation. Information (line number n of line Ln of scanning line 5 in the example of FIG. 15), each image data D, each offset correction value O, and the like are transmitted to radiation image processing apparatus 50. Further, the radiation image processing apparatus 50 stores these data in the storage unit 57.

  Hereinafter, the case where the repair process is performed by the radiation image processing apparatus 50 will be described, but the case where the repair process is performed by the radiation image capturing apparatus 1 itself will be described in the same manner.

Before performing the restoration processing of the image data D, the radiation image processing device 50 firstly performs the following (1) based on the image data D after the radiographic image transmission transmitted from the radiographic image capturing device 1 and the offset correction value O. ), True image data D ^* corresponding to only the charges generated in each radiation detection element 7 by irradiation of radiation and not including dark charge is calculated for each radiation detection element 7. The calculated true image data D ^* is a target of the restoration process.
D ^* = DO (1)

Further, a true image obtained by subtracting data corresponding to the dark charge from the image data d according to the following equation (2) based on the image data d and the offset correction value o read out in the readout process before radiographic image capturing. Data d ^* is calculated for each radiation detection element 7.
d ^* = d-o (2)

The true image data d ^* is calculated only for image data d in a range set based on the following methods (that is, image data d read during radiation irradiation). It is also possible, and it is also possible to configure so that the image data d of all the radiation detection elements 7 is performed in advance.

Next, the scanning line 5 to which an on-voltage is applied between the time when the radiation imaging apparatus 1 is actually irradiated and the time when it is detected that the irradiation is started (that is, during the irradiation of radiation) ( In the example of FIG. 15, a restoration process based on the true image data d ^* of the true image data D ^* of each radiation detection element 7 connected to the lines Ln−2 to Ln) of the scanning line 5 will be described.

When performing the repair process, as described above, the radiation image capturing apparatus 1 itself cannot detect the point in time when the radiation irradiation of the radiation image capturing apparatus 1 is actually started. It is not known whether the true image data D ^* of each connected radiation detection element 7 should be restored. Therefore, first, there is a problem of how to set the range of the radiation detection element 7 to be subjected to the restoration processing of the true image data D ^* . Hereinafter, four types of methods will be described as methods for setting the range, but the method is not limited to these.

[Method 1]
As a first method, the range of the radiation detection element 7 that restores the true image data D ^* is detected at or just before the start of radiation irradiation in the readout process before radiographic image capturing. Examples of the method include the radiation detection elements 7 that include the scanning lines 5 to which the on-voltage is applied and are connected to a predetermined number of scanning lines 5 to which the on-voltage has been previously applied.

For example, the predetermined number is set to 10 or the like in advance, and in the example shown in FIG. 15, the scanning in which the on-voltage is applied at the time of detecting the start of radiation irradiation or just before that is detected. Since the line 5 is the line Ln of the scanning line 5, the radiographic image processing device 50 refers to the line number (n in this case) of the scanning line 5 transmitted from the radiographic image capturing device 1. The radiation detection elements 7 connected to the lines Ln-9 to Ln are within the range of the radiation detection elements 7 for restoring the true image data D ^* .

  Note that in this case (the same applies to the following cases), the above-mentioned predetermined number is between the time when the radiation imaging apparatus 1 is actually irradiated with radiation and the time when radiation irradiation is detected. The number of scanning lines 5 (on the line Ln-2 to Ln of the scanning line 5 in the example of FIG. 15) where the on-voltage is expected to be applied is set to be greater than or equal to the number.

  Therefore, in the above case, the number of scanning lines 5 to which the on-voltage is applied after the actual radiation is applied and before the start of the radiation irradiation is detected will be less than 10. However, when there is a possibility that the ON voltage may be applied to a larger number of scanning lines 5, the predetermined number is set to a larger number.

[Method 2]
In addition, the true image data D ^* calculated from the image data D read out in the reading process after radiographic imaging is analyzed to set the range of the radiation detection element 7 for restoring the true image data D ^*. It is also possible to configure.

Specifically, in the example shown in FIG. 15, for example, in the true image data D ^* , the on-voltage is applied at the time of detecting the start of radiation irradiation or just before it is detected. Each of the radiation detection elements connected to the scanning line 5 for each scanning line 5 with respect to the lines Ln-9 to Ln + 10 of 10 scanning lines before and after the line Ln of the scanning line 5 The average value of the true image data D ^* of 7 is calculated. A total value may be used instead of the average value.

The reason for calculating the average value (or the total value; hereinafter the same is omitted) is that the true image data D ^* includes noise, and thus each of the true image data D ^* is calculated. The analysis may be difficult due to the influence of noise as it is, but by calculating the average value in this way, the noise of the individual true image data D ^* cancels out and is canceled out.

Therefore, when the average value D ^* ave for each scanning line 5 is plotted in the order of the line number k of the scanning line 5, a trend of transition of the average value D ^* ave is obtained as shown in FIG. Among them, each radiation detection element connected to the scanning line 5 to which the on-voltage has been applied at the time of detecting or detecting that the line Ln of the scanning line 5, that is, the start of radiation irradiation, is detected. The average value D ^* ave of the true image data D ^* of 7 is greatly deviated from the trend of the overall transition.

Then, when the scanning line 5 in which the average value D ^* ave of the true image data D ^* of each radiation detection element 7 starts to deviate from the trend of the overall transition is analyzed, the line Ln-2 of the scanning line 5 in the example of FIG. I understand that. Therefore, in this case, for example, the scanning line 5 in which the average value D ^* ave deviates from the trend by a predetermined threshold or more is determined to be the scanning line 5 to which the on-voltage is applied while radiation is being applied. If configured, it can be considered that radiation irradiation to the radiation imaging apparatus 1 has started at or just before the on-voltage is applied to the line Ln-2 of the scanning line 5.

In the method 2, irradiation of radiation is started by analyzing the average value D ^* ave calculated from the true image data D ^{* of} each radiation detection element connected to each scanning line 5 in this way. Based on the image data D read from each radiation detection element 7 connected to each scanning line 5 including the line Ln of the scanning line 5 to which the on-voltage was applied immediately before or after the detection. The true image data D ^* is analyzed, and the range of the radiation detection element 7 that restores the true image data D ^* is determined. That is, in the above example, it is determined as the range of each radiation detection element 7 connected to the lines Ln−2 to Ln of the scanning line 5.

[Method 3]
In the above method 2, analyzes the true image data D ^* based on the image data D and it read in the reading process after radiation image capturing range of the radiation detection element 7 to repair the true image data D ^* It was determined.

On the other hand, the range of the radiation detection element 7 for restoring the true image data D ^* is determined by analyzing the image data d read out in the read-out process before radiographic image capture and the true image data d ^* based thereon. It is also possible to configure as described above.

Specifically, also in this case, the example shown in FIG. 15 will be described. For example, in the true image data d ^* calculated according to the above equation (2), it is detected that radiation irradiation has started. For each of the scanning lines 5, the line Ln-9 to Ln of each of the previous ten scanning lines 5, including the line Ln of the scanning line 5 to which the ON voltage was applied at or immediately before, An average value d ^* ave of true image data d ^* of each radiation detection element 7 connected to the scanning line 5 is calculated.

  In this case, the total value may be used instead of the average value. The advantage of using the average value is the same as described above.

Then, when the average value d ^* ave for each scanning line 5 is plotted in the order of the line number k of the scanning line 5, the average value d ^* ave is actually irradiated to the radiation imaging apparatus 1 as shown in FIG. Before the operation, the value is substantially 0, but the line Ln-2 of the scanning line 5 to which the on-voltage is applied two lines before the line Ln of the scanning line 5 where it is detected that radiation irradiation has started is detected. The value becomes significantly different from 0.

Therefore, also in this case, if the scanning line 5 that starts to deviate from the trend of the transition of the average value d ^* ave of the true image data d ^* of each radiation detection element 7 is analyzed, the line Ln− of the scanning line 5 in the example of FIG. Therefore, it can be considered that the radiation imaging apparatus 1 has started irradiation of radiation at the time when the on-voltage is applied to the line Ln-2 of the scanning line 5 or just before that.

In the method 3, radiation irradiation is started by analyzing the average value d ^* ave calculated from the true image data d ^{* of} each radiation detection element calculated according to the above-described equation (2) in this way. The image data d read from each radiation detection element 7 connected to each scanning line 5 including the line Ln of the scanning line 5 to which the on-voltage was applied immediately before or after the detection was made. Based on the true image data d ^* based thereon, the range of the radiation detection element 7 for restoring the true image data D ^* is determined. That is, also in the above example, the range of each radiation detection element 7 connected to the lines Ln-2 to Ln of the scanning line 5 is determined.

[Method 4]
In the above method 2 and method 3, the calculated true image data D ^* and true image data d ^* are analyzed, and the range of the radiation detection element 7 for restoring the true image data D ^* is set. As described above, in the present embodiment, whether or not radiation irradiation has started is determined by the voltage value corresponding to the current flowing through the connection 10 of the bias line 9 output from the current detection unit 43. This is performed based on V.

  Then, as described above, the start of radiation irradiation in the radiographic imaging apparatus 1 is detected by the time tc (see FIG. 14) when the voltage value V output from the current detection means 43 exceeds a preset threshold value Vth. The time differential value of the voltage value V exceeds a preset threshold value td. If the voltage value V output from the current detection unit 43 is analyzed in detail, the radiographic image capturing apparatus 1 is actually analyzed. It can be seen that the point in time at which radiation irradiation is started is the point in time tb.

Therefore, the voltage value V corresponding to the current flowing through the connection 10 of the bias line 9 output from the current detection means 43 is analyzed, and the point in time when radiation irradiation is actually started (in the case of FIG. 14, tb). At the time tb or immediately after that, the scanning line 5 to which the on-voltage is applied is determined, and the on-voltage is detected at the time when it is detected that radiation irradiation has been started from the scanning line 5 thus calculated. Is configured to determine each radiation detection element 7 connected to each line L of the scanning line 5 up to the scanning line 5 to which the laser beam has been applied as a range of the radiation detection element 7 for restoring the true image data D ^*. It is also possible to do.

In this case, the analysis of the voltage value V output from the current detection unit 43 may be performed by the control unit 22 of the radiographic image capturing apparatus 1, and in this case, information on the calculated time tb is obtained from the radiographic image capturing apparatus 1. It is transmitted to the radiation image processing apparatus 50. Further, when the control means 22 itself of the radiographic image capturing apparatus 1 performs the repair process of the true image data D ^* , the repair process is performed based on the information determined by itself.

  When the radiation image processing apparatus 50 analyzes the voltage value V output from the current detection unit 43, information on the voltage value V is transmitted from the radiation image capturing apparatus 1 to the radiation image processing apparatus 50. In that case, it is not necessary to transmit all the voltage values V output from the current detection means 43, and it is sufficient to transmit data of the voltage values V from a point in time when it is detected that radiation irradiation has been started to a predetermined time before. .

  The range can be determined by appropriately combining the above methods 2 to 4. Further, the method 1 and the method 2 to the method 4 are appropriately combined. For example, the range determined by the method 2 to the method 4 only when the range determined by the method 2 to the method 4 exceeds the predetermined range of the method 1. In other cases, the predetermined range of the method 1 may be adopted.

Next, the radiation image processing apparatus 50 calculates the true image data D ^* calculated according to the above equation (1) for each radiation detection element 7 connected to each scanning line 5 in the range set as described above ^. The restoration processing based on the true image data d ^* is performed.

The true image data D ^* corresponding to only the charges (not including the dark charge) generated in each radiation detection element 7 due to radiation irradiation is read out in a read process after radiographic imaging in a normal case. The image data D is included in the image data D, and can be calculated by subtracting the offset correction value O from the image data D as shown in the above equation (1).

However, as can be seen from FIG. 15, for example, in each radiation detection element 7 connected to the lines Ln−2 to Ln of the scanning line 5, charges generated in each radiation detection element 7 due to radiation irradiation (that is, A part of the charge (corresponding to the true image data D ^* ) is read out by the reading process of the image data d before radiographic imaging, and is included in the read image data d.

That is, in each of the radiation detection elements 7 connected to the lines Ln-2 to Ln of the scanning line 5, the original image data to be read out from each radiation detection element 7, that is, the true image data D ^* is obtained before radiographic image capturing. Can be regarded as being divided and read out by the reading process of the above and the reading process after radiographic imaging.

Then, a part of the true image data D ^* included in the image data d can be calculated by subtracting the offset correction value o from the image data d according to the above equation (2). It corresponds to d ^* .

Therefore, as the simplest repair process, the radiation image processing apparatus 50 is connected to each scanning line 5 (lines Ln-2 to Ln of the scanning line 5 in the example of FIG. 15) within the range set as described above. For each radiation detection element 7, the true image data D ^* calculated according to the above equation (1) and the true image data d ^* calculated according to the above equation (2) are added to detect each radiation detection It can be configured to restore the true image data D ^* of the element 7.

If comprised in this way, it will become possible to restore | repair the true image data D ^* of each radiation detection element 7 easily and exactly.

On the other hand, if the reading process of the image data d before the radiographic image capturing is performed while the radiation image capturing apparatus 1 is irradiated with the radiation, the following unique phenomenon occurs. For this reason, it is possible to restore the true image data D ^* of each radiation detection element 7 in consideration of the influence of this phenomenon.

  That is, in the radiographic image capturing apparatus 1, a very small amount of electric charge accumulated in each radiation detection element 7 leaks to the signal line 6 through each TFT 8. As shown in FIG. 22, for example, when the on-voltage is applied to the line Li of the scanning line 5 and the charge Q is released from the radiation detection element 7 i to the signal line 6, Charge q flows from each radiation detection element 7 into the same signal line 6.

  Then, the sum of the charge Q from the radiation detection element 7i and each of the very small charges q leaked from the other radiation detection elements 7 is subjected to charge-voltage conversion by the amplifier circuit 18 to obtain image data di of the radiation detection element 7i. Read out. In FIG. 22, the charge leaking from the other radiation detection elements 7 via the TFT 8 is described as q, but this is a description for convenience, and the same amount of charges from each of the other radiation detection elements 7 is described. It does not mean that q leaks.

  Moreover, when radiation is irradiated to the radiographic imaging device 1, in this embodiment, the irradiated radiation is converted into an electromagnetic wave by the scintillator 3 (see FIG. 2 and the like), and this electromagnetic wave is irradiated to each TFT 8. When each TFT 8 is irradiated with electromagnetic waves, electron-hole pairs are generated in each TFT 8, and the amount of leakage current flowing in each TFT 8 increases, and is accumulated in each radiation detection element 7 in each TFT 8. The amount of charge leakage increases.

  In addition, since a charge is newly generated in each radiation detection element 7 due to radiation irradiation, and the amount of accumulated charge in each radiation detection element 7 also increases, each radiation detection is performed via each TFT 8 in that amount. The amount of charge q leaking from the element 7 to the signal line 6 increases.

  Therefore, the value of the image data di corresponding to the sum of the charges Q from the radiation detection elements 7 i and the charges q leaked from the other radiation detection elements 7 is transmitted from the other radiation detection elements 7 via the TFTs 8. The amount of charge q that leaks and flows into the same signal line 6 increases by an increase.

  On the other hand, when the offset correction value o is acquired before the radiation image capturing apparatus 1 is irradiated with radiation, an increase due to irradiation of the charge q leaked from these other radiation detection elements 7 via the TFT 8 is obtained. The offset correction value o is a value that does not include an increase due to the radiation of the charge q leaking from the other radiation detection elements 7.

Therefore, when the true image data d ^* is calculated by subtracting the offset correction value o from the image data d according to the above equation (2), the true image data d ^* is a part of the true image data D ^* described above. It is not a value of itself, but is a value obtained by adding an increase due to the irradiation of the charge q leaked from the other radiation detection element 7 described above.

In the simplest repair process, the true image data D ^* and the true image data d ^* are simply ignored by ignoring the increase due to the radiation of the charge q leaking from the other radiation detection elements 7. Is equivalent to adding to. When the increase of the charge q leaked from the other radiation detection elements 7 due to the irradiation of radiation is very small, the true image data D ^* of each radiation detection element 7 can be restored effectively and accurately even in this restoration process. Is possible.

Further, when considering the influence of the increase of the charge q leaked from the other radiation detection element 7 due to the irradiation of radiation, for example, the dose per unit time of the radiation irradiated to the radiation image capturing apparatus 1, that is, the dose rate A coefficient whose value changes according to the above is experimentally obtained in advance, and the true image data d ^* is multiplied by the coefficient and the true image data D ^* to add the true value of each radiation detection element 7. The image data D ^* can be restored.

For example, when radiation with a certain dose rate is irradiated, the true image data d ^* is increased by 10% of the original value by the increase due to the irradiation of the radiation of the charge q leaked from the other radiation detection element 7 ( That is, when read as a value of 1.1 times), the true image data d ^* calculated based on the read image data d is reciprocal of 1.1 (that is, 1 / 1.1 = A value obtained by multiplying by about 0.9) is added to the true image data D ^* .

With this configuration, the true image data D ^* of each radiation detection element 7 can be more accurately restored by eliminating the influence of the unique phenomenon that occurs while the radiation is being applied. Become.

In addition, it is possible to perform a process for setting the true image data D ^* of each radiation detection element 7 restored as described above to a more appropriate value, and an appropriate process is performed. . Needless to say, normal image processing such as logarithmic conversion processing and gradation processing is performed on the restored true image data D ^* .

  As described above, according to the radiographic image capturing apparatus 1 according to this embodiment, the radiographic image capturing apparatus 1 itself is provided by detecting the current flowing through the wiring in the apparatus such as the bias line 9 by providing the current detection unit 43. Thus, it is possible to detect the start of radiation irradiation. In addition, as in the conventional example, the radiation detection start is not performed while performing the reset process of each radiation detection element 7 before the radiographic image is captured, but the reading of the image data d is performed before the radiographic image is captured. Wait for the start of irradiation.

  For this reason, the point in time when irradiation of the radiation imaging apparatus 1 is actually started is different from the point in time when it is detected that irradiation is started, and the scanning line 5 is turned on while radiation is being irradiated. Even when the voltage is applied and the reading process of the image data d is performed, it is not necessary to treat the scanning line 5 to which the on-voltage is applied during irradiation with radiation as a line defect as in the conventional example. It is possible to accurately restore the image data D read out in the readout process after radiographic image capturing using the image data d read out in step (b).

  The radiographic image capturing apparatus 1 is configured to perform not only the readout process after radiographic image capture but also the read process before radiographic image capture as described above, and the image read out by the read process after radiographic image capture. Since not only the data D but also the image data d read out in the reading process before radiographic image capturing is stored in the storage means 40, the image data D is repaired as described above. In addition, it is possible to restore the image data D by reliably using the image data d read out by the reading process before radiographic image capturing.

  Further, according to the radiographic image capturing apparatus 1 and the radiographic image processing apparatus 50 according to the present embodiment, as described above, the image data D can be accurately restored based on the image data d before radiographic image capturing. At the same time, the point in time when irradiation of the radiation imaging apparatus 1 is actually started is different from the point in time when it is detected that irradiation is started. Even when the on-voltage is applied and the image data d is read, the scanning lines 5 are not treated as line defects, and the image data D is restored with the image data d.

  Therefore, when a radiographic image captured by the radiographic image capturing apparatus 1 is used for medical diagnosis or the like, information on a lesion that has been lost in the case of a line defect is the image data D as described above. Since it is not lost by the restoration and remains in the radiographic image, it becomes possible for a doctor or the like to accurately diagnose the lesion by viewing the radiographic image.

  In the above embodiment, the case where the current detection unit 43 is configured to detect the current flowing through the bias line 9 or the connection 10 has been described. However, the radiation imaging apparatus 1 is irradiated with radiation. Then, current flows not only in the bias line 9 and the connection line 10 but also in each scanning line 5 for the following reason.

  That is, when radiation irradiation starts on the radiation image capturing apparatus 1, as described above, radiation incident on the radiation image capturing apparatus 1 is converted into electromagnetic waves by the scintillator 3, and the converted electromagnetic waves are directly below the radiation detection element. 7 reaches the i layer 76 (see FIG. 5), and electron-hole pairs are generated in the i layer 76 of the radiation detection element 7. Therefore, in the radiation detection element 7, the potential of the first electrode 74 with respect to the second electrode 78 changes.

  In the present embodiment, a predetermined negative bias voltage is applied to the second electrode 78 from the bias power source 14 via the bias line 9 so that the potential is fixed, and the positive electrode generated in the i layer 76 is positive. In the hole pair, holes move to the second electrode 78 side and electrons move to the first electrode 74 side, so that the potential on the first electrode 74 side decreases. When the potential on the first electrode 74 side of the radiation detection element 7 is lowered, the potential on the source electrode 8s (denoted as S in FIG. 8) side of the TFT 8 shown in FIG. 8 is lowered accordingly.

  In the TFT 8, a kind of capacitor is formed by the gate electrode 8g, the source electrode 8s, and the insulating layer 81 (see FIG. 5) between them, and there is a parasitic capacitance between the gate electrode 8g and the source electrode 8s. Existing. Since the potential on the source electrode 8s side of the TFT 8 is lowered as described above with respect to the gate electrode 8g of the TFT 8 to which a predetermined off voltage is applied and the potential does not change, the gate electrode 8g and the source electrode 8s of the TFT 8 The potential difference changes.

  Therefore, charges corresponding to the changed potential difference are supplied to the gate electrode 8 g of the TFT 8 through the scanning line 5. That is, a current flows through the scanning line 5 with the irradiation of radiation.

  Therefore, instead of providing the current detection means 43 on the bias line 9 or its connection 10 as shown in FIGS. 7 and 8, for example, as shown in FIG. Alternatively, the current detection means 43 can be configured to detect the value of the current flowing in the scanning line 5 or the binding wire 24 by connecting the binding wire 24 to the binding wire 24.

  Further, a current corresponding to the total amount of current flowing through each of the lines L1 to Lx of the scanning line 5 flows on the wiring connecting the power supply circuit 15a of the scanning driving means 15 and the gate driver 15b. In the scanning drive unit 15, for example, as shown in a simplified manner in FIG. 24, the on-voltage and the off-voltage are separately supplied from the power supply circuit 15a to the gate driver 15b via the wiring 15con and the wiring 15coff, respectively. It has become.

  Further, a switching element 15d is provided in each gate terminal 15b for each terminal to which each scanning line 5 is connected, and is applied to each scanning line 5 by switching the connection of the switching element 15d. The voltage is configured to be switched between an on voltage and an off voltage.

  When the scanning drive unit 15 is configured in this way, as described above, when all the scanning lines 5 or the reading process are performed during the reading process of the image data d before the radiographic image capturing. Since the off-voltage is applied to the scanning lines 5 other than the scanning line 5 to which the on-voltage is applied, all or most of the current flowing through each scanning line 5 as a result of irradiation with radiation as described above. Eventually, the current flows through the wiring 15coff connecting the power supply circuit 15a and the gate driver 15b.

  Therefore, for example, as shown in FIG. 24, the current detection unit 43 is provided on the wiring 15coff connecting the power supply circuit 15a and the gate driver 15b of the scanning driving unit 15, and the current detection unit 43 detects the current flowing in the wiring 15coff. It can also be configured to detect the value.

  In either case, the voltage output by the current detection means 43 is the same as in the case of the above-described embodiment, whether it is configured as shown in FIG. 23 or as shown in FIG. By monitoring the value V, that is, the voltage value V corresponding to the current flowing through the scanning line 5 and the wiring 15off, it is possible to accurately detect that radiation irradiation has started.

  In addition, it goes without saying that the present invention is not limited to the above-described embodiments and can be modified as appropriate.

DESCRIPTION OF SYMBOLS 1 Radiographic imaging apparatus 5, L1-Lx Scan line 6 Signal line 7 Radiation detection element 8 TFT (switch means)
15 Scanning drive means 15a Power supply circuit 15b Gate driver 22 Control means 40 Storage means 43 Current detection means 50 Radiation image processing apparatus D, d Image data D Image data d read out in read-out process after radiation irradiation is completed Radiation image photography Image data Ln-2 to Ln read in the previous reading process Range of scanning line for restoring image data O Offset correction value Q Charge r Region V Voltage value (current value detected by current detection means)

Claims (15)

A plurality of scanning lines and a plurality of signal lines arranged so as to intersect with each other; a plurality of radiation detecting elements arranged in a two-dimensional manner in each region partitioned by the plurality of scanning lines and the plurality of signal lines; ,
When an off voltage is applied to the connected scanning line, which is arranged for each of the radiation detecting elements, it is turned off, holds charges generated in the radiation detecting element, and an on voltage is applied to the connected scanning line. A switching means that is turned on and emits the charge from the radiation detection element;
Scan driving means comprising: a gate driver that switches a voltage applied to the switch means via the scanning line between an on voltage and an off voltage; and a power supply circuit that supplies the on voltage and the off voltage to the gate driver. When,
Current detection means for detecting current flowing in the device;
Storage means for storing image data read from each of the radiation detection elements;
Prior to radiographic imaging, the scanning drive means sequentially applies an on-voltage to each scanning line and performs a readout process of reading out the image data from each radiation detection element to obtain the image data for each radiation detection element. When it is detected that radiation irradiation has been started based on the value of the current stored in the storage means and output from the current detection means, the reading process of the image data from each radiation detection element is stopped. The scan driving means applies an off voltage to each scanning line, and shifts to a charge accumulation mode for accumulating charges generated in each radiation detection element by irradiation with radiation. After the irradiation is completed, an on-voltage is sequentially applied again from the scanning drive means to the scanning lines, and the image from each radiation detecting element is again applied. And a control means for saving said performing read processing of data the image data for each radiation detection element in the storage means,
A radiographic imaging apparatus comprising:   The scanning drive means determines the time from applying an on voltage to the scanning line to switching the applied voltage to an off voltage during the readout process, the readout process before radiographic imaging, and the radiation irradiation. The radiographic image capturing apparatus according to claim 1, wherein the same time is used for the reading process after the process is completed.   In the readout process after the radiation irradiation is completed, the control means applies an on-voltage at or immediately before detecting the start of radiation irradiation in the readout process before the radiographic imaging. 3. The radiation according to claim 1, wherein a reading process of the image data from each of the radiation detection elements is performed from the scanning line to which an on-voltage is to be applied next to the scanning line. Image shooting device.   After the completion of the reading process after the radiation irradiation is completed, the control means applies the scanning line to each scanning line at the same timing as the on-voltage is applied to each scanning line in the reading process before the radiographic image capturing. Applying an on-voltage to each of the scanning lines by sequentially applying an on-voltage and applying the on-voltage to the scanning lines that had been applied with the on-voltage immediately before or after detecting the start of radiation irradiation Is turned off for each scanning line in a state in which the radiation is not irradiated for the same time as the time from the detection of the start of the radiation irradiation to the start of the reading process after the radiation irradiation is completed. After the voltage is applied, the on-voltage is applied to each scanning line at the same timing as the on-voltage is applied to each scanning line in the readout process after the radiation irradiation is completed. Applied to a radiographic imaging apparatus according to any one of claims 1 to 3, characterized in that to perform the offset correction value readout process for reading each offset correction value from each radiation detection element.   After the completion of the reading process after the radiation irradiation is completed, the control means applies the scanning line to each scanning line at the same timing as the on-voltage is applied to each scanning line in the reading process before the radiographic image capturing. 5. The radiographic image capturing apparatus according to claim 4, wherein when the on-voltage is sequentially applied, reset processing of each radiation detection element is performed without reading image data from each radiation detection element.   In the offset correction value readout process, the control means detects the start of radiation irradiation in the readout process before radiographic image capture, or immediately before the scanning line to which the ON voltage was applied. 6. The radiographic imaging apparatus according to claim 4, wherein a readout process is performed from the scanning line to which an ON voltage is to be applied next.   The control means includes the scanning line to which an on-voltage is applied at or just before the start of radiation irradiation in the readout process before the radiographic image capturing, and the on-voltage before the time For each of the radiation detection elements connected to a predetermined number of the scanning lines to which image data is applied, the image data read out in the readout process before the radiographic image capturing and after the radiation irradiation is completed The radiographic image capturing apparatus according to any one of claims 1 to 6, wherein the image data of the radiation detection element is restored based on the image data read out by the readout process. .   When the control means detects that irradiation of radiation has been started in the readout process before radiographic imaging out of the image data read out in the readout process after the radiation irradiation has ended, or The scanning for repairing the image data by analyzing the image data read from the radiation detecting elements connected to the scanning lines including the scanning line to which an on-voltage has been applied immediately before A range of lines is determined, and for each of the radiation detection elements connected to the scanning line within the determined range, the image data read out in the readout process before the radiographic image capture and the radiation The image data of the radiation detection element is restored based on the image data read out in the reading process after the irradiation is completed. Radiographic imaging apparatus according to any one of claims 1 to 6.   The control unit is configured to apply the on-voltage at or immediately before detecting the start of radiation irradiation among the image data read out in the readout process before the radiographic image capturing. Analyzing the image data read from each of the radiation detection elements connected to each of the scanning lines including a line, determining a range of the scanning line for repairing the image data, and within the determined range For each of the radiation detection elements connected to the scanning line, the image data read in the readout process before the radiographic image capturing and the readout process after the radiation irradiation is completed are read out. 7. The radiographic imaging according to claim 1, wherein the image data of the radiation detection element is restored based on the image data. Apparatus.   The control means analyzes the value of the current output from the current detection means to determine the scanning line to which an on-voltage is applied at or immediately after the start of radiation irradiation. The range of the scanning line for repairing the image data is determined, and the radiation detection elements connected to the scanning line in the determined range are read by the readout process before the radiographic image capturing. The image data of the radiation detection element is restored based on the image data and the image data read out in the readout process after the radiation irradiation is completed. The radiographic imaging apparatus according to any one of claims 6 to 7. A radiographic image processing apparatus that restores the image data based on at least the image data transmitted from the radiographic image capturing apparatus according to any one of claims 1 to 6,
The scanning line to which an on-voltage was applied immediately before or after the start of radiation irradiation in the readout process before the radiographic image capturing is included, and a predetermined voltage to which the on-voltage was applied before the time For each of the radiation detection elements connected to the number of the scanning lines, the image data read in the readout process before the radiographic image capturing and the readout process after the radiation irradiation is completed are read out. A radiation image processing apparatus, wherein the image data of the radiation detection element is restored on the basis of the image data thus obtained. A radiographic image processing apparatus that restores the image data based on at least the image data transmitted from the radiographic image capturing apparatus according to any one of claims 1 to 6,
Of the image data read out in the read-out process after the radiation irradiation is completed, the on-voltage is detected at or just before the start of the radiation irradiation in the read-out process before the radiographic image capturing. Analyzing the image data read from each radiation detecting element connected to each scanning line including the scanning line to which the image data has been applied, and determining a range of the scanning line for restoring the image data And about each said radiation detection element connected to the said scanning line in the determined said range, after completion | finish of irradiation of the said image data read by the read-out process before the radiographic image imaging, and the said radiation A radiographic image processing apparatus that restores the image data of the radiation detection element based on the image data read out in the readout process. A radiographic image processing apparatus that restores the image data based on at least the image data transmitted from the radiographic image capturing apparatus according to any one of claims 1 to 6,
Each of the image data read out in the read-out process before radiographic image capturing includes each of the scanning lines to which an on-voltage has been applied at the time of detecting the start of radiation irradiation or just before that. Analyzing the image data read from each of the radiation detection elements connected to the scanning line, determining a range of the scanning line for repairing the image data, and determining the scanning line within the determined range. For each of the connected radiation detection elements, the image data read in the read process before radiographic imaging, and the image data read in the read process after the radiation irradiation ends The radiological image processing apparatus recovers the image data of the radiation detection element based on the above. 2. The control unit analyzes the value of the current output from the current detection unit, and determines the scanning line to which an on-voltage is applied at or immediately after the start of radiation irradiation. A radiographic image processing apparatus that restores the image data based on at least the image data transmitted from the radiographic image capturing apparatus according to claim 6,
A range of the scanning line for repairing the image data is determined based on the information on the scanning line transmitted from the radiographic imaging device, and each of the radiations connected to the scanning line within the determined range. For the detection element, the radiation detection is performed based on the image data read in the read process before the radiographic image capturing and the image data read in the read process after the irradiation of the radiation is completed. A radiation image processing apparatus, wherein the image data of an element is restored. A radiographic image processing apparatus that restores the image data based on at least the image data transmitted from the radiographic image capturing apparatus according to any one of claims 1 to 6,
Analyzing the value of the current output from the current detection means transmitted from the radiographic imaging device, the on-voltage is applied at or immediately after the start of radiation irradiation actually A scan line is determined to determine a range of the scan line for repairing the image data, and for each of the radiation detection elements connected to the scan line within the determined range, read processing before radiographic imaging The image data of the radiation detection element is restored based on the image data read in step (a) and the image data read in the read process after the radiation irradiation is completed. Radiation image processing device.

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