JP2011234915A - Radiation image photographing system and radiation image photographing apparatus - Google Patents

Abstract

Provided are a radiographic image capturing system capable of acquiring a radiographic image of an appropriate image quality and a radiographic image capturing device constituting the radiographic image capturing system even if a radiographic image capturing device and a radiation generating device do not cooperate.
A radiographic imaging device 1 starts execution of a reset process for resetting the radiation detection element 7 by releasing electric charges from the radiation detection element 7 by a predetermined trigger, and when the reset process is completed, the reset process is completed. And a transition to the charge accumulation mode in which charges are accumulated in the radiation detection element 7, and when transitioning to the charge accumulation mode, the value of the current detected by the current detection means 41 decreases and falls below a predetermined threshold value Vth. When the end of radiation irradiation is detected at the time point, and the end of radiation irradiation is detected, an electric charge is emitted from the radiation detection element 7 to the signal line 6 and the read circuit 17 converts the emitted electric charge into image data. A transition is made to a read mode in which data read processing is performed.
[Selection] Figure 1

Description

  The present invention relates to a radiographic image capturing system and a radiographic image capturing 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 types of so-called indirect radiographic imaging devices have been developed that convert charges into electromagnetic signals after they have been converted into electromagnetic waves of a wavelength, and then generated by 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 imaging apparatus is known as an FPD (Flat Panel Detector), and conventionally formed integrally with a support base (or a bucky apparatus) (see, for example, Patent Document 1). A portable radiographic imaging device in which an 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 a radiographic imaging system including such a radiographic imaging device and a radiation generation device that irradiates radiation to the radiographic imaging device, a signal or radiation indicating that radiation irradiation is started at the time of radiographic imaging A signal to end the irradiation of the radiation is transmitted from the radiation generator to the radiation image capturing apparatus, and accordingly the radiation image capturing apparatus transitions to a charge accumulation mode in which charges are accumulated in each radiation detection element, or each radiation In many cases, the detection element is configured to be changed to a reading mode in which electric charges are discharged to read out image data of a radiation image.

  However, when the radiographic imaging apparatus and the radiation generating apparatus are configured in this way to link with each other, it is necessary to accurately construct an interface between the radiographic imaging apparatus and the radiation generating apparatus. Building an interface is not always easy.

  If the interface is not properly constructed and the transmission / reception signal for starting radiation irradiation is not accurately performed, for example, excess charge remaining in each radiation detection element on the radiation imaging apparatus side. There is a possibility that the irradiation of radiation will start during the reset process for releasing the light, and the charges generated by the irradiation of the radiation will flow out of each radiation detection element by the reset process. If the charge flows out from each radiation detection element in the reset process, the efficiency of conversion to the charge of the irradiated radiation, that is, the image data is reduced, and a radiographic image with an appropriate image quality cannot be obtained. Arise.

In addition, if the interface is not properly constructed and a signal for ending radiation irradiation is not properly transmitted / received, for example, even if radiation irradiation is completed, the radiographic imaging device is in charge accumulation mode. Therefore, there is a possibility that the reading mode is not easily changed.
In a radiographic imaging apparatus, even when no radiation is irradiated, dark charges are generated in each radiation detection element due to thermal excitation of the radiation detection element by heat, etc., and this charge is stored in the radiation detection element, ie, image data. The offset due to dark charge is included. For this reason, normally, dark image acquisition processing in which data for offset due to dark charges (hereinafter referred to as “dark image data”) is read from each radiation detection element and a correction dark image is acquired is performed separately from the radiographic image capturing processing. There are many cases.
In this case, the dark image acquisition process is normally performed in the same sequence as the radiographic image capturing process. However, in the dark image acquisition process, unlike the radiographic image capturing process, radiation is not irradiated during the charge accumulation mode. The radiographic imaging device is left unattended.

  When such a dark image acquisition process is performed subsequent to the radiographic image capturing process, the timing for starting the dark image acquisition process is also delayed unless the transition to the reading mode is made during the radiographic image capturing process as described above. . In addition, as described above, the state of the charge accumulation mode becomes long if it does not easily change to the readout mode at the time of radiographic imaging processing, but the charge accumulation mode becomes long even in the dark image acquisition process performed in the same sequence as that, There is a problem that the time from the start of the radiation image capturing process to the end of the dark image acquisition process becomes long.

  In addition, in a radiographic imaging element such as a photodiode, the amount of dark charge generated according to the temperature changes. Therefore, in order to obtain a more accurate correction dark image, a radiographic imaging process and a dark image are performed. It is preferable that the temperature conditions and the like are close to each other during the acquisition process. However, if the timing for starting the dark image acquisition process is delayed as described above, the temperature conditions and the like change between the radiographic image capturing process and the dark image acquisition process, and the offset due to the dark charge included in the image data There is a possibility that a large difference is generated between the offset data obtained as the dark image data and the image data cannot be corrected accurately.

  Therefore, in recent years, various techniques have been developed for the purpose of detecting that radiation has been emitted by the radiation imaging apparatus itself, without using such an interface between the radiation imaging apparatus and the radiation generation apparatus. ing.

  For example, in the invention described in Patent Document 4, when radiation is started on the radiation imaging apparatus and a charge is generated in each radiation detection element, a bias connected from each radiation detection element to each radiation detection element. By utilizing the fact that the electric charge flows out to the line and the current flowing through the bias line increases, a current detection means is provided on the bias line to monitor the value of the current flowing through the bias line, It has been proposed to detect the start and end.

  Specifically, a radiographic imaging apparatus that monitors the value of the current flowing in the bias line and detects the start or end of radiation irradiation based on the increase or decrease, for example, first applies an on-voltage to the scanning line. As a result, a transition is made to a reset mode in which a reset process is performed in which extra radiation is discharged from the radiation detection element to reset the radiation detection element. During the reset mode, the value of the current flowing in the bias line is monitored, and the start of radiation irradiation is detected based on the value.

  When the start of radiation irradiation is detected, a transition is made from the reset mode to a charge accumulation mode in which charges are accumulated in the radiation detection element by applying an off voltage to the scanning line. At this time, an on-voltage is intentionally applied to some scanning lines so that the end of radiation irradiation can be detected based on the value of the current flowing in the bias line. If an on-voltage is applied to some scanning lines in the charge accumulation mode, the switch means connected to the scanning line to which the on-voltage is applied is turned on, and the radiation detecting element connected to the on-state switch means The charge generated by the irradiation of radiation, that is, image data flows out and a line defect is generated. This line defect is corrected later.

  When the end of radiation irradiation is detected, the mode shifts from the charge accumulation mode to a readout mode in which an image data is read out by discharging the accumulated charge from the radiation detection element by applying an ON voltage to the scanning line. Is configured to do.

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

However, if the current detection means is provided on the bias line as described above and the start and end of radiation irradiation are detected based on the increase or decrease of the current value flowing through the bias line, the radiation detection element is connected via the bias line. The noise generated by the current detecting means is superimposed on the bias voltage applied to the voltage applied.
The noise of the voltage generated by the current detection means is superimposed as the noise charge on the charge generated in the radiation detection element due to the irradiation of radiation, so that the image quality of the finally obtained radiation image is affected by the influence of the noise charge. In particular, there is a possibility that problems such as a deterioration in the granularity and a failure to obtain a radiographic image with an appropriate image quality may occur.

In the radiographic imaging apparatus as described above, each radiation detection element itself is formed small in order to increase the resolution of the radiographic image. However, in order to increase the light collection rate as much as possible when viewed with respect to each radiation detection element. In addition, it is designed such that the area of the light collecting surface such as a photodiode becomes as large as possible in a limited space. Therefore, the parasitic capacitance of the radiation detection element is relatively large.
Therefore, when the current detecting means is provided on the bias line as described above, the noise of the voltage generated by the current detecting means, that is, the noise with respect to the bias voltage is relatively large parasitic of the radiation detecting element according to the relationship of Q = CV. In other words, the capacitance C is amplified to a relatively large noise charge, which is superimposed on the charge generated in the radiation detection element due to the irradiation of radiation, so that the degradation of the image quality of the finally obtained radiation image further increases. There is a high risk that a radiographic image having an appropriate image quality cannot be obtained.

  Furthermore, as described above, in radiographic imaging such as that described above, on-voltages are applied to several scanning lines in the charge accumulation mode, so that line defects and the like occur. Although line defects are corrected later, it is difficult to correct such line defects accurately, and there is a possibility that problems such as failure to obtain a radiation image having an appropriate image quality may occur.

  If the image quality of the radiographic image deteriorates, especially when its granularity deteriorates or a line defect occurs, for example, when making a diagnosis using such a radiographic image, the lesion is overlooked or the normal part is There is a risk of inconvenience such as misdiagnosis by mistaking it as a lesion. For this reason, it is desirable for a radiographic imaging apparatus to obtain a radiographic image with an appropriate image quality in which the influence of noise and image defects are eliminated as much as possible.

  The present invention has been made in view of the above-described problems, and a radiographic imaging system capable of acquiring a radiographic image with an appropriate image quality even when the radiographic imaging device and the radiation generation device do not cooperate with each other and the radiation. It aims at providing the radiographic imaging apparatus which comprises an imaging system.

In order to solve the above-described problem, the radiographic imaging system of the present invention includes:
A radiation image capturing apparatus that performs a radiation image capturing process, a console that performs predetermined image processing on image data of the radiation image captured by the radiation image capturing apparatus, and irradiating the radiation image capturing apparatus with radiation In a radiographic imaging system comprising a radiation generator,
The radiographic image capturing apparatus includes:
A plurality of scanning lines and a plurality of signal lines arranged so as to cross each other, and a plurality of radiation detection elements arranged in a two-dimensional manner in each region partitioned by the plurality of scanning lines and the plurality of signal lines A detection unit comprising:
When each of the radiation detection elements is arranged and connected, the off-state is applied to the connected scanning line, and the on-state is applied when the on-voltage is applied to the connected scanning line. Then, the switch means for accumulating the charge generated in the radiation detection element in the radiation detection element, and releasing the charge from the radiation detection element to the signal line in the ON state,
A scan driver comprising: a gate driver that switches a voltage applied to the scan line between the on voltage and the off voltage; and a power supply circuit that supplies the on voltage and the off voltage to the gate driver;
A readout circuit that performs an image data readout process of reading out the image data from the radiation detection element by converting the charge emitted from the radiation detection element into the image data;
Current detection means for detecting a current flowing through a wiring connecting the power supply circuit and the gate driver, or a current flowing through the scanning line;
Informing means for informing completion of a reset process for resetting the radiation detection element;
Control means for controlling at least the scanning drive means, the readout circuit and the notification means;
With
The control means includes
Initiating execution of the reset process for releasing the electric charge from the radiation detection element by resetting the radiation detection element by applying the on-voltage to the scanning line from the scanning drive unit by a predetermined trigger,
When the reset process is completed, the completion of the reset process is notified via the notification means, and the off-voltage is applied to all the scanning lines from the scanning drive means, thereby the charge in the radiation detection element. Transition to charge accumulation mode to accumulate
When transitioning to the charge accumulation mode, when the value of the current detected by the current detection means decreases and falls below a predetermined threshold, the end of radiation irradiation by the radiation generator is detected,
When the end of irradiation of the radiation is detected, the charge is discharged from the radiation detection element by applying the ON voltage to the scanning line from the scanning drive unit, and the discharged charge is output to the image reading circuit. The image data reading process is changed to data to make a transition to a reading mode.

Moreover, the radiographic imaging system of the present invention is
A radiation image capturing apparatus that performs a radiation image capturing process, a console that performs predetermined image processing on image data of the radiation image captured by the radiation image capturing apparatus, and irradiating the radiation image capturing apparatus with radiation In a radiographic imaging system comprising a radiation generator,
The radiographic image capturing apparatus includes:
A plurality of scanning lines and a plurality of signal lines arranged so as to cross each other, and a plurality of radiation detection elements arranged in a two-dimensional manner in each region partitioned by the plurality of scanning lines and the plurality of signal lines A detection unit comprising:
When each of the radiation detection elements is arranged and connected, the off-state is applied to the connected scanning line, and the on-state is applied when the on-voltage is applied to the connected scanning line. Then, the switch means for accumulating the charge generated in the radiation detection element in the radiation detection element, and releasing the charge from the radiation detection element to the signal line in the ON state,
A scan driver comprising: a gate driver that switches a voltage applied to the scan line between the on voltage and the off voltage; and a power supply circuit that supplies the on voltage and the off voltage to the gate driver;
A readout circuit that performs an image data readout process of reading out the image data from the radiation detection element by converting the charge emitted from the radiation detection element into the image data;
Informing means for informing completion of a reset process for resetting the radiation detection element;
Control means for controlling at least the scanning drive means, the readout circuit and the notification means;
With
The control means includes
Initiating execution of the reset process for releasing the electric charge from the radiation detection element by resetting the radiation detection element by applying the on-voltage to the scanning line from the scanning drive unit by a predetermined trigger,
When the reset process is completed, the completion of the reset process is notified via the notification means, and the off-voltage is applied to all the scanning lines from the scanning drive means, thereby the charge in the radiation detection element. Transition to charge accumulation mode to accumulate
When transitioning to the charge accumulation mode, the readout circuit periodically performs a readout operation, and repeats leak data readout processing for converting the charge leaked from the radiation detection element via the switch means into leak data. When the value of the leak data decreases and falls below a predetermined threshold, the end of radiation irradiation by the radiation generator is detected,
When the end of irradiation of the radiation is detected, the charge is discharged from the radiation detection element by applying the ON voltage to the scanning line from the scanning drive unit, and the discharged charge is output to the image reading circuit. The image data reading process is changed to data to make a transition to a reading mode.

Moreover, the radiographic imaging device of the present invention is
A plurality of scanning lines and a plurality of signal lines arranged so as to cross each other, and a plurality of radiation detection elements arranged in a two-dimensional manner in each region partitioned by the plurality of scanning lines and the plurality of signal lines A detection unit comprising:
When each of the radiation detection elements is arranged and connected, the off-state is applied to the connected scanning line, and the on-state is applied when the on-voltage is applied to the connected scanning line. Then, the switch means for accumulating the charge generated in the radiation detection element in the radiation detection element, and releasing the charge from the radiation detection element to the signal line in the ON state,
A scan driver comprising: a gate driver that switches a voltage applied to the scan line between the on voltage and the off voltage; and a power supply circuit that supplies the on voltage and the off voltage to the gate driver;
A readout circuit that performs an image data readout process for reading out the image data from the radiation detection element by converting the electric charge emitted from the radiation detection element into image data;
Current detection means for detecting a current flowing through a wiring connecting the power supply circuit and the gate driver, or a current flowing through the scanning line;
Informing means for informing completion of a reset process for resetting the radiation detection element;
Control means for controlling at least the scanning drive means, the readout circuit and the notification means;
With
The control means includes
Initiating execution of the reset process for releasing the electric charge from the radiation detection element by resetting the radiation detection element by applying the on-voltage to the scanning line from the scanning drive unit by a predetermined trigger,
When the reset process is completed, the completion of the reset process is notified via the notification means, and the off-voltage is applied to all the scanning lines from the scanning drive means, thereby the charge in the radiation detection element. Transition to charge accumulation mode to accumulate
When transitioning to the charge accumulation mode, when the value of the current detected by the current detection means decreases and falls below a predetermined threshold, the end of radiation irradiation is detected,
When the end of irradiation of the radiation is detected, the charge is discharged from the radiation detection element by applying the ON voltage to the scanning line from the scanning drive unit, and the discharged charge is output to the image reading circuit. The image data reading process is changed to data to make a transition to a reading mode.

Moreover, the radiographic imaging device of the present invention is
A plurality of scanning lines and a plurality of signal lines arranged so as to cross each other, and a plurality of radiation detection elements arranged in a two-dimensional manner in each region partitioned by the plurality of scanning lines and the plurality of signal lines A detection unit comprising:
When each of the radiation detection elements is arranged and connected, the off-state is applied to the connected scanning line, and the on-state is applied when the on-voltage is applied to the connected scanning line. Then, the switch means for accumulating the charge generated in the radiation detection element in the radiation detection element, and releasing the charge from the radiation detection element to the signal line in the ON state,
A scan driver comprising: a gate driver that switches a voltage applied to the scan line between the on voltage and the off voltage; and a power supply circuit that supplies the on voltage and the off voltage to the gate driver;
A readout circuit that performs an image data readout process for reading out the image data from the radiation detection element by converting the electric charge emitted from the radiation detection element into image data;
Informing means for informing completion of a reset process for resetting the radiation detection element;
Control means for controlling at least the scanning drive means, the readout circuit and the notification means;
With
The control means includes
Initiating execution of the reset process for releasing the electric charge from the radiation detection element by resetting the radiation detection element by applying the on-voltage to the scanning line from the scanning drive unit by a predetermined trigger,
When the reset process is completed, the completion of the reset process is notified via the notification means, and the off-voltage is applied to all the scanning lines from the scanning drive means, thereby the charge in the radiation detection element. Transition to charge accumulation mode to accumulate
When transitioning to the charge accumulation mode, the readout circuit periodically performs a readout operation, and repeats leak data readout processing for converting the charge leaked from the radiation detection element via the switch means into leak data. When the value of the leak data decreases and falls below a predetermined threshold, the end of radiation irradiation is detected,
When the end of irradiation of the radiation is detected, the charge is discharged from the radiation detection element by applying the ON voltage to the scanning line from the scanning drive unit, and the discharged charge is output to the image reading circuit. The image data reading process is changed to data to make a transition to a reading mode.

According to the radiation image capturing system and the radiation image capturing apparatus of the system as in the present invention, the radiation image capturing apparatus is configured to notify the completion of the reset process for resetting the radiation detection element.
As a result, even if the radiographic imaging apparatus and the radiation generating apparatus do not cooperate, an operator such as a radiographer operates the radiation generating apparatus so that irradiation of the radiographic imaging apparatus is started in response to the notification. In this case, the radiation irradiation is surely started after the reset process is completed on the radiation imaging apparatus side. Therefore, it is possible to avoid the start of radiation irradiation during the reset process on the radiation image capturing apparatus side, and it is possible to acquire a radiation image with an appropriate image quality.

Further, according to the radiographic imaging system and radiographic imaging apparatus of the system as in the present invention, the radiographic imaging apparatus is configured to shift to the reading mode when detecting the end of radiation irradiation.
Thus, since the radiographic imaging device can quickly transition from the charge accumulation mode to the readout mode without cooperating with the radiation generation device, it is avoided that the state of the charge accumulation mode becomes unnecessarily long. Is done. Therefore, when dark image acquisition processing is performed after radiographic image capturing processing, temperature conditions and the like can be made close during radiographic image capturing processing and dark image income processing, so image data can be corrected accurately. Therefore, it is possible to acquire a radiographic image with an appropriate image quality.

In addition, according to the radiographic imaging system and radiographic imaging apparatus of the system of the present invention, the radiographic imaging apparatus detects a current flowing through a wiring connecting a power supply circuit and a gate driver or a current flowing through a scanning line. A current detection unit is provided, and the end of radiation irradiation can be detected based on the value of the current detected by the current detection unit.
Therefore, compared with the case where the current detection means is provided on the bias line, since the noise generated in the current detection means is superimposed on the charge generated in each radiation detection element by irradiation of radiation, that is, image data, only a little. It is possible to reduce the influence of noise generated by the current detection means. Therefore, the occurrence of problems such as deterioration of the image quality of the finally obtained radiographic image, particularly the granularity thereof is avoided, and it is possible to acquire a radiographic image having an appropriate image quality.
In addition, since the radiographic imaging device can detect the end of radiation irradiation without applying an on-voltage to some scanning lines when transitioning to the charge accumulation mode, the radiographic image is finally obtained. Generation | occurrence | production of problems, such as a line defect, is avoided, and it becomes possible to acquire the radiographic image of appropriate image quality.

Alternatively, according to the radiation image capturing system and the radiation image capturing apparatus of the system as in the present invention, the radiation image capturing apparatus leaks from the radiation detection element using the readout circuit provided in the normal radiation image capturing apparatus. The charge thus read out is read as leak data, and the end of radiation irradiation can be detected based on the leak data.
That is, since it is not necessary to provide a current detection means for detecting the end of radiation irradiation, voltage noise generated by the current detection means is superimposed on the charge generated in each radiation detection element by radiation irradiation, that is, image data. It will not be done. Therefore, the occurrence of problems such as deterioration of the image quality of the finally obtained radiographic image, particularly the granularity thereof is avoided, and it is possible to acquire a radiographic image having an appropriate image quality.
In addition, since the radiographic imaging device can detect the end of radiation irradiation without applying an on-voltage to some scanning lines when transitioning to the charge accumulation mode, the radiographic image is finally obtained. Generation | occurrence | production of problems, such as a line defect, is avoided, and it becomes possible to acquire the radiographic image of appropriate image quality.

It is a figure which shows the whole structure of the radiographic imaging system which concerns on each embodiment. (A) is a figure which shows the structure of an operation switch, (B) is a state which the button part was half-pressed, (C) is a figure explaining the state by which the button part was fully pressed. It is a perspective view which shows the radiographic imaging apparatus which concerns on each 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 the radiographic imaging apparatus which concerns on 1st Embodiment. It is a block diagram showing the equivalent circuit about 1 pixel which comprises the detection part in the radiographic imaging apparatus which concerns on 1st Embodiment. It is an equivalent circuit diagram showing the configuration of the current detection means and the internal configuration of the gate driver. 6 is a timing chart showing the charge reset switch, pulse signal, and TFT on / off timing during image data read processing. It is a graph showing the change of the voltage value etc. in a correlated double sampling circuit. It is a timing chart showing the timing which switches the voltage applied to each scanning line between an ON voltage and an OFF voltage in image data read-out processing. 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 by the sequential reset from a radiation detection element. 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 by the simultaneous sequential reset from a radiation detection element. 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 by the collective reset from a radiation detection element. It is a graph showing the example of the voltage value corresponded to the electric current detected by an electric current detection means. It is a figure showing the flow of a radiographic imaging process and a dark image acquisition process. It is a flowchart for demonstrating the process regarding the radiographic imaging by the radiographic imaging apparatus in the radiographic imaging system which concerns on 1st Embodiment. It is a figure explaining each electric charge which leaks from each radiation detection element via each TFT. It is a graph showing the example of the leak data read by the read-out circuit. It is a block diagram showing the equivalent circuit of the radiographic imaging apparatus which concerns on 2nd Embodiment. It is a block diagram showing the equivalent circuit about 1 pixel which comprises the detection part in the radiographic imaging apparatus which concerns on 2nd Embodiment. 6 is a timing chart showing charge reset switches, pulse signals, and TFT on / off timings during leak data read processing. It is a flowchart for demonstrating the process regarding the radiographic imaging by the radiographic imaging apparatus in the radiographic imaging system which concerns on 2nd Embodiment.

  Embodiments of a radiographic image capturing system and a radiographic image capturing 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 radiographic image capturing apparatus formed integrally with a support base or the like.

[First Embodiment]
[Radiation imaging system]
FIG. 1 is a diagram illustrating an overall configuration of a radiographic image capturing system according to the present embodiment.
For example, as shown in FIG. 1, the radiographic imaging system 50 includes a radiographing room R1 that irradiates radiation and shoots a subject that is a part of the patient (a radiographing target area of the patient), and the radiographing room R1. Then, an operator such as a radiologist is arranged in the front chamber R2 where various operations such as control of the start of irradiation of radiation to the subject are performed, and outside thereof.

  Specifically, as shown in FIG. 1, the radiographic image capturing system 50 performs predetermined processing on a radiographic image capturing apparatus 1 that performs a radiographic image capturing process and image data of a radiographic image captured by the radiographic image capturing apparatus 1. A console 58 that performs the image processing, and a radiation generator 52 that irradiates the radiation image capturing apparatus 1 with radiation.

  In the radiographing room R1, for example, a Bucky device 51 that can be loaded with the radiographic imaging device 1, and a radiation generation device 52 that includes a radiation source (not shown) including an X-ray tube that generates radiation to irradiate the subject. A base station 54 that includes a wireless antenna 53 and relays communication between the radiation image capturing apparatus 1 and an external device such as the console 58 is provided.

In FIG. 1, when the portable radiographic imaging device 1 is used by being loaded into the cassette holding part 51a of the bucky device 51, or when it is used in a single state where it is not loaded into the bucky device 51, specifically, Although it is shown that the patient's hand as a subject is placed on the radiation incident surface R (see FIG. 3) and used on the upper surface side of the bucky device 51B for position photographing. The image capturing device 1 may be formed integrally with the bucky device 51, a support base or the like.
Here, when the portable radiographic image capturing apparatus 1 is used in a state where it is not loaded in the bucky device 51, the radiation incident surface R is disposed on the upper surface side of the bucky device 51 </ b> B for lying position imaging (see FIG. 3). In addition to placing and using the patient's hand as a subject on the subject, for example, the subject is placed on the upper surface side of a bed or the like provided in the imaging room R1, and the subject is placed on the radiation incident surface R (see FIG. 3). It is also possible to place a patient's hand or the like, or, for example, to insert between a patient's waist or legs lying on the bed and the bed.

In FIG. 1, the radiographic image capturing apparatus 1 and the base station 54 are wirelessly connected so that communication between the radiographic image capturing apparatus 1 and an external device can be performed via the base station 54 in a wireless manner. The radiographic image capturing apparatus 1 and the base station 54 are wired by a LAN (Local Area Network) cable or the like, and communication between the radiographic image capturing apparatus 1 and an external device is performed. You may comprise so that it can carry out by a wired system via the base station 54. FIG.
It is also possible to wire-connect the Bucky device 51 with the base station 54. In this case, communication between the radiographic imaging device 1 loaded in the Bucky device 51 and the external device is made via the base station 54. Can be done in a wired manner.

Further, FIG. 1 shows a case in which one of the standing-up shooting bucky device 51A and the standing-up shooting bucky device 51B is provided as the bucky device 51 in the shooting room R1. The number and type of the bucky devices 51 provided in the photographing room R1 are not particularly limited.
Further, FIG. 1 shows a case where one radiation generating device 52A associated with the bucky device 51 and one portable radiation generating device 52B are provided as the radiation generating device 52 in the imaging room R1. However, the number and type of radiation generators 52 provided in the imaging room R1 are not particularly limited.

[Radiation generator]
In the radiographing room R1, a radiation generating device 52 that irradiates the radiographic imaging device 1 with radiation is provided.
In the present embodiment, an operation console 57 of the radiation generating device 52 is provided in the front room R2 adjacent to the imaging room R1, and an operator such as a radiologist is attached to the radiation generating device 52 on the operation console 57. On the other hand, an operation switch 56 is provided for operating when instructing the start of radiation irradiation or the like.

  For example, as shown in FIG. 2A, the operation switch 56 includes a rod-shaped button portion 56a having a predetermined length of stroke, and a casing that supports the button portion 56a so as to be movable in the stroke direction indicated by an arrow S in the drawing. It is comprised with the part 56b. The button portion 56a of the operation switch 56 includes, for example, a cylindrical portion 56a1 protruding upward from the housing portion 56b and a columnar portion 56a2 protruding further upward from the inside thereof.

As shown in FIG. 2B, when the columnar portion 56a2 is pushed in the stroke direction S up to the upper end portion of the cylindrical portion 56a1 (that is, when a so-called half-pressing operation is performed), the operation switch 56 is moved to the console 57. The activation signal is transmitted to the radiation generator 52 via the.
When the radiation generator 52 receives the activation signal, the radiation source 52 is configured to start the rotation of the anode of the X-ray tube of the radiation source and to put the radiation source in a standby state.

Furthermore, as shown in FIG. 2C, when both the cylindrical portion 56a1 and the columnar portion 56a2 of the operation switch 56 are pushed to the upper end portion of the housing portion 56b (that is, when a so-called full pushing operation is performed). The operation switch 56 is configured to transmit an irradiation signal to the radiation generator 52 via the console 57.
And the radiation generator 52 is comprised so that radiation may be irradiated from the X-ray tube of a radiation source, if this irradiation signal is received.

  Here, in the present embodiment, as will be described later, the indicator 37 of the radiographic image capturing apparatus 1 is turned on or blinked, for example, so that the surplus remaining in each radiation detection element 7 included in the radiographic image capturing apparatus 1 is obtained. When the completion of the reset process for releasing each electric charge and resetting each radiation detection element 7 is notified, an operator such as a radiographer operates the operation switch 56 to start irradiation of the radiation generator 52 with radiation. It comes to direct.

  In addition, the radiation generating device 52 adjusts the radiation irradiation direction so that the radiation image capturing device 1 is appropriately irradiated with radiation by the operator such as a radiologist operating the console 57 or manually. (See FIG. 1), adjusting the diaphragm so that radiation is irradiated within a predetermined region of the radiographic imaging apparatus 1, or adjusting the radiation source so that an appropriate dose of radiation is irradiated It is configured to be able to.

[console]
For example, as shown in FIG. 1, the console 58 includes a display unit 58a composed of a CRT (Cathode Ray Tube), an LCD (Liquid Crystal Display), etc., a storage means 59 composed of an HDD (Hard Disk Drive), etc. A control unit (not shown) for controlling the operation and the like of each unit, and a communication unit (not shown) connected to the base station 54 via a LAN cable or the like and for communicating with other devices such as the radiographic imaging device 1 And a computer including an input unit (not shown) including a keyboard and a mouse.

Although FIG. 1 shows the case where the console 58 is provided outside the imaging room R1 and the front room R2, the console 58 may be provided in the front room R2, for example.
1 shows the case where the storage means 59 is connected to the console 58, the storage means 59 may be built in the console 58.

When the communication unit receives the image data of the radiographic image captured by the radiographic image capturing apparatus 1 from the radiographic image capturing apparatus 1 via the base station 54, the control unit of the console 58 performs decompression processing on the image data, Predetermined image processing such as offset correction processing and gain correction processing is performed to create diagnostic image data.
Then, the control unit of the console 58 displays a radiographic image based on the diagnostic image data on the display unit 58a or communicates the diagnostic image data in accordance with an instruction from the input unit or the like operated by the operator. Or the like and transmitted to another device (not shown) such as an imager or a data management server.

  In this embodiment, the offset correction process, the gain correction process, and the like are described as being performed by the console 58. However, the radiation image capturing apparatus 1 may perform the offset correction process, the gain correction process, and the like.

  The control unit of the console 58 receives the radiation irradiation dose calculated by the radiographic imaging device 1 from the radiographic imaging device 1 when the communication unit receives the radiation irradiation dose calculated by the radiographic imaging device 1 via the base station 54. Is displayed on the display unit 58a. Thereby, a radiographer, a doctor, etc. can grasp the dose of radiation irradiated from the radiation generator 52 to the radiographic imaging device 1.

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

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.
3 and 4 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.

  Further, as shown in FIG. 3, in the present embodiment, for the replacement of the power switch 36, the indicator 37 composed of LEDs and the like, and the battery 40 (see FIG. 9 described later) on the side surface portion of the housing 2. A lid member 38 that can be opened and closed is disposed. In the present embodiment, the antenna device 39 is embedded in the side surface of the lid member 38.

Here, the antenna device 39 functions as a communication means for transmitting and receiving information such as data and signals to and from an external device such as the console 58 via the base station 54.
When the communication between the radiographic image capturing apparatus 1 and the external apparatus is performed by the wired system as described above, the radiographic image capturing apparatus 1 is provided with a connector for connecting a LAN cable or the like as a communication unit. It is done.

The indicator 37 functions as a notification unit that notifies an operator such as a radiographer of completion of a reset process (described later) for resetting each radiation detection element 7.
In the present embodiment, it will be described that the completion of the reset process is notified by emitting light, that is, by turning on or blinking the indicator 37. However, the present invention is not limited to this, and an operator such as a radiologist If the completion of the reset process can be notified, the notification method is arbitrary, and for example, it can also be performed by emitting a sound. When the notification is performed by making a sound, the radiographic imaging apparatus 1 is provided with a buzzer or the like that emits a sound as a notification means. The radiographic imaging device 1 can also perform notification from an external device by communicating with an external device such as the console 58 and instructing the external device to perform the notification. When communicating with the external device and performing the notification from the external device, the communication means such as the antenna device 39 and the external device function as the notification means.

  As shown in FIG. 4, 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 an electronic component 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 scintillator 3 on the radiation incident surface R side is disposed.

  The scintillator 3 is arranged in a state of facing a detection unit P (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. 5, 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. A radiation detection element 7 is provided in each 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.

  Thus, the entire region r in which the plurality of radiation detection elements 7 arranged in a two-dimensional manner are provided in each 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 a source electrode 8s of a thin film transistor (hereinafter referred to as TFT) 8 as a switch means, as shown in FIG. 5 or FIG. 6 which is an enlarged view of FIG. The drain electrode 8 d of the TFT 8 is connected to the signal line 6.

The TFT 8 is turned on when an on-voltage is applied to the connected scanning line 5 by the scanning driving means 15 described later and applied to the gate electrode 8g via the scanning line 5, and the radiation detection element The electric charge accumulated in 7 is emitted from the radiation detection element 7 to the signal line 6.
The TFT 8 is turned off when an off voltage is applied to the connected scanning line 5 and applied to the gate electrode 8 g via the scanning line 5, and the charge from the radiation detection element 7 to the signal line 6 is turned off. The charge generated in the radiation detection element 7 is 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 a cross-sectional view shown in FIG. 7 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 detection element 7, an auxiliary electrode 72 is formed by laminating Al, Cr or the like on an 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. Note that the auxiliary electrode 72 is not necessarily provided.

  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.

  And at the time of radiographic imaging, the radiation irradiated with respect to the radiographic imaging apparatus 1 injects from the radiation entrance surface R of the housing | casing 2, is converted into electromagnetic waves, such as visible light, with the scintillator 3, and the converted electromagnetic waves are illustrated. When irradiated from above, the electromagnetic wave reaches the i layer 76 of the radiation detection element 7, and electron-hole pairs are generated in the i layer 76. In this way, the radiation detection element 7 converts the electromagnetic waves irradiated from the scintillator 3 into electric charges (electron hole pairs).

  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, it is not limited to this.

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. 5 and 6, in the present 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 the present embodiment, as shown in FIG. 5, 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. 8, each input / output terminal 11 has an anisotropic COF (Chip On Film) 12 in which a chip such as a gate IC 12a constituting a gate driver 15b of the scanning drive means 15 described later is incorporated on the film. They are connected via an anisotropic conductive adhesive material 13 such as an anisotropic conductive adhesive film or an 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. 8, 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. 9 is a block diagram illustrating an equivalent circuit of the radiographic imaging apparatus 1 according to the present embodiment, and FIG. 10 is a block diagram illustrating 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.
The bias power supply 14 is connected to a control means 22 described later, and the control means 22 controls the bias voltage applied to each radiation detection element 7 from the bias power supply 14.

  As shown in FIGS. 9 and 10, in this embodiment, it can be understood that the bias line 9 is connected to the p-layer 77 side (see FIG. 7) of the radiation detection element 7 via the second electrode 78. In addition, the bias power supply 14 supplies a voltage equal to or lower than a voltage applied to the second electrode 78 of the radiation detection element 7 via the bias line 9 as a bias voltage on the first electrode 74 side of the radiation detection element 7 (that is, a so-called reverse bias voltage). Is applied.

  The first electrode 74 of each radiation detection element 7 is connected to the source electrode 8s (denoted as S in FIGS. 9 and 10) of the TFT 8, and the gate electrode 8g (FIGS. 9 and 10) of each TFT 8. Are respectively connected to the lines 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. 9 and 10) of each TFT 8 is connected to each signal line 6.

  The scanning drive means 15 includes a power supply circuit 15a that supplies an on voltage and an off voltage to the gate driver 15b via the wiring 15c, and a voltage applied to each line L1 to Lx of the scanning line 5 between the on voltage and the off voltage. And a gate driver 15b for switching the TFT 8 between the on state and the off state.

  In the present embodiment, the current detection means 41 for detecting the current flowing between the power supply circuit 15a and the gate driver 15b of the scanning drive means 15 is provided on the wiring 15c. The current detection means 41 can also be configured to detect a current flowing through one or a plurality of scanning lines 5 among the lines L1 to Lx of the scanning lines 5.

  Here, the configuration of the current detection means 41 will be described. In this embodiment, as shown in FIG. 11, the current detection means 41 supplies an off voltage from the power supply circuit 15a to the gate driver 15b among the wiring 15c connecting the power supply circuit 15a and the gate driver 15b of the scan drive means 15. The wiring 15coff is provided.

  In this embodiment, as shown in a simplified manner in FIG. 11, a switch element 15d is provided for each terminal to which each scanning line 5 is connected, inside the gate driver 15b of the scanning driving means 15. Yes. Then, by switching the connection of the switch elements 15d, the voltage applied to each scanning line 5 is changed to the on voltage supplied from the power supply circuit 15a via the wiring 15con and the off voltage supplied via the wiring 15coff. It is comprised so that it can each switch between.

  In this embodiment, the current detection means 41 includes a resistor 41a having a predetermined resistance value connected in series to the wiring 15coff, a diode 41b connected in parallel thereto, and an input side terminal connected to both terminals of the resistor 41a. And a differential amplifier 41c connected to each other. The differential amplifier 41c is supplied with power from the power supply means 45.

  The current detection means 41 measures the voltage V between both terminals of the resistor 41a with the differential amplifier 41c, and determines the current flowing through the resistor 41a, that is, the current flowing between the power supply circuit 15a and the gate driver 15b as a voltage. It is converted into a value V, detected, and output to the control means 22.

  As the resistor 41a provided in the current detection means 41, a resistor having a resistance value capable of converting the current flowing through the wiring 15coff into an appropriate voltage value V is used. A current flows from the power supply circuit 15a to the scanning line 5 side through the gate driver 15b in the wiring 15coff. The diode 41b is for preventing current from flowing in the opposite direction. It is not always necessary to provide it.

  Further, when it is not necessary to detect radiation irradiation on the radiographic imaging apparatus 1, the resistance of the resistor 41a prevents the supply of the off voltage from the power supply circuit 15a to the gate driver 15b. Therefore, the current detection means 41 is provided with a switch 41d for short-circuiting both terminals of the resistor 41a when detection of radiation irradiation is unnecessary.

  As shown in FIGS. 9 and 10, each signal line 6 is connected to each readout circuit 17 formed in the readout IC 16. In the present embodiment, the readout IC 16 is provided with one readout circuit 17 for each signal line 6.

  The readout circuit 17 includes an amplification circuit 18 and a correlated double sampling circuit 19. An analog multiplexer 21 and an A / D converter 20 are further provided in the reading IC 16. 9 and 10, the correlated double sampling circuit 19 is represented as CDS. In FIG. 10, the analog multiplexer 21 is omitted.

  In the present embodiment, the amplifier circuit 18 is formed of a charge amplifier circuit, and includes an operational amplifier 18a, a capacitor 18b and a charge reset switch 18c connected in parallel to the operational amplifier 18a. In addition, a power supply unit 18 d for supplying power to the amplifier circuit 18 is connected to the amplifier circuit 18.

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. . 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 TFT 8 is turned on while the charge reset switch 18c is turned off (that is, when a turn-on voltage is applied to the gate electrode 8g of the TFT 8 via the scanning line 5), each TFT 8 that is turned on is turned on. The charge accumulated from each radiation detection element 7 is discharged to the signal line 6 through the signal line 6, and the charge flows through the signal line 6 and flows into the capacitor 18 b of the amplifier circuit 18 and is accumulated.

  In the amplifier circuit 18, a voltage value corresponding to the amount of charge accumulated in the capacitor 18b is output from the output side of the operational amplifier 18a. In this way, the amplifier circuit 18 outputs a voltage value according to the amount of charge output from each radiation detection element 7 and converts the charge voltage.

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.
When the amplifier circuit 18 is reset, when the charge reset switch 18c is turned on, the input side and the output side of the amplifier circuit 18 are short-circuited, and the charge accumulated in the capacitor 18b is discharged. Then, the discharged electric charge passes through the operational amplifier 18a from the output terminal side of the operational amplifier 18a, goes out from the non-inverting input terminal and is grounded, or flows out to the power supply unit 18d, so that the amplifier circuit 18 is reset. It has become.

  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 for reading image data from each radiation detection element 7, as shown in FIG. 12, the control means 22 first starts the charge reset switch 18 c of the amplification circuit 18 of each reading circuit 17. To turn it 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. 13, 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. 13). It changes by the amount of electric charge caused by kTC noise and changes to a voltage value Vin. At this stage, as shown in FIG. 12, the control means 22 transmits the first pulse signal Sp1 to the correlated double sampling circuit 19, and holds the voltage value Vin output from the amplifier circuit 18 at that time. (In FIG. 13, “CDS hold” (left side) is displayed).

  Subsequently, the control unit 22 applies an ON voltage to one scanning line 5 (for example, the line Ln of the scanning line 5) from the gate driver 15b of the scanning driving unit 15, and the gate electrode 8g is connected to the scanning line 5. The TFT 8 that has been turned on is turned on (see FIG. 12; “TFTon” is displayed in FIG. 13). Then, the charge accumulated in the radiation detection element 7 from each radiation detection element 7 to which these TFTs 8 are connected flows into the capacitor 18b of the amplifier circuit 18 via each signal line 6 and is accumulated, as shown in FIG. Thus, the voltage value output from the amplifier circuit 18 increases according to the amount of charge accumulated in the capacitor 18b.

  Next, 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 as shown in FIG. The TFT 8 connected to is turned off (indicated as “TFToff” in FIG. 13). At this stage, the control means 22 transmits the second pulse signal Sp2 to each correlated double sampling circuit 19, and holds the voltage value Vfi output from the amplifier circuit 18 at that time (in FIG. 13, “ CDS retention "(right side)).

When each correlated double sampling circuit 19 holds the voltage value Vfi by the second pulse signal Sp2, it calculates the difference “Vfi−Vin” of the voltage value, and calculates the calculated difference “Vfi−Vin” as an analog value. The image data is output downstream.
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 43 and sequentially stored.

  Further, as shown in FIG. 14, the control unit 22 sequentially switches the lines L1 to Lx of the scanning line 5 to which the on-voltage is applied from the gate driver 15b of the scanning driving unit 15, and for each switching, as described above. An image data reading process for reading image data from each radiation detecting element 7 is performed.

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. 9 and the like, the control means 22 is connected with a storage means 43 composed of a DRAM (Dynamic RAM) or the like.

In the present embodiment, an antenna device 39 is connected to the control means 22.
Further, in the present embodiment, the control means 22 is connected with a battery 40 for supplying electric power to each of the functional parts such as the detection part P, the scanning drive means 15, the readout circuit 17, the storage means 43, and the bias power supply 14. Has been. Further, when the battery 40 is charged by supplying power to the battery 40 from a charging device (not shown), a connection terminal 44 that connects the charging device and the battery 40 is attached to the battery 40.

  As described above, the control unit 22 controls the bias power supply 14 to set or vary the bias voltage applied from the bias power supply 14 to each radiation detection element 7. It is designed to control the operation.

<Reset processing>
In the radiographic imaging, the control means 22 obtains the radiographic image in order to obtain the charge, that is, the image data, which is generated and accumulated in each radiation detection element 7 by irradiating the radiographic imaging device 1 as accurately as possible. Prior to imaging, a reset process is performed to reset each radiation detection element 7 by discharging excess charges remaining in each radiation detection element 7 from each radiation detection element 7.

The reset of the radiation detection element 7 can be realized by applying an on-voltage to the scanning line 5 from the scanning drive unit 15 and releasing extra charge from the radiation detection element 7 to the signal line 6.
As a method for resetting the radiation detection element 7, the following various methods can be employed.

  As a first method, as shown in FIG. 15, the on / off timing of each TFT 8, that is, the timing at which the on-voltage is applied to each line L 1 to Lx of the scanning line 5 from the gate driver 15 b of the scanning driving means 15. A method of resetting each radiation detection element 7 while sequentially switching can be employed. For the sake of simplicity, the first method is hereinafter referred to as “sequential reset”.

  Specifically, in the sequential reset, for example, each switch element 15d of the gate driver 15b illustrated in FIG. 11 is connected to the off voltage side, that is, the wiring 15coff side to which the off voltage is supplied from the power supply circuit 15a. Then, the switching element 15d to be connected to the ON voltage side, that is, the wiring 15con side to which the ON voltage is supplied from the power supply circuit 15a is sequentially switched.

  In this embodiment, as shown in FIG. 15, when performing sequential resetting, each line L <b> 1 to Lx of the scanning line 5 is scanned at the same timing as the image data reading process for reading image data from each radiation detection element 7. Although the description will be made assuming that the voltage to be applied is switched between the on-voltage and the off-voltage, the on-voltage application timing and the on-voltage application time for each of the lines L1 to Lx of the scanning line 5 can be appropriately set.

  As the second method, as shown in FIG. 16, an 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 means 15 as in the case of sequential resetting (see FIG. 15). Each radiation detection element 7 is reset while sequentially switching the timing to be performed. At that time, a method of resetting each radiation detection element 7 by simultaneously applying an ON voltage to a plurality of lines L of the scanning line 5 is adopted. can do. For the sake of simplicity, this second method is hereinafter referred to as “simultaneous sequential reset”.

  Here, as described above, in this embodiment, the gate driver 15b of the scanning drive unit 15 is formed by arranging a plurality of gate ICs 12a in parallel. However, each gate IC 12a has 256 scanning lines 5 respectively. It is assumed that it is connected.

  Specifically, the simultaneous sequential reset is performed, for example, in the gate ICs 12a themselves, and the lines L of the corresponding scanning lines 5 connected to the gate ICs 12a, that is, the nth lines L (line Ln). , Line L (n + 256), line L (n + 512), etc. In this case, n can be realized by applying an ON voltage simultaneously to 1 ≦ n ≦ 256.

  In the present embodiment, it is described that 256 scanning lines 5 are connected to each gate IC 12a. However, the number of scanning lines 5 connected to each gate IC 12a can be set as appropriate.

  As a third method, as shown in FIG. 17, the voltage applied from the gate driver 15b of the scanning drive unit 15 to each of the lines L1 to Lx of the scanning line 5 is simultaneously switched from the off voltage to the on voltage, and then again. A method of resetting each radiation detection element 7 by switching to the off-voltage all at once can be adopted. For the sake of simplicity, this third method is hereinafter referred to as “batch reset”.

  Specifically, the collective reset is performed, for example, after all the switch elements 15d of the gate driver 15b shown in FIG. 11 are connected to the on-voltage side from the state connected to the off-voltage side and then turned off all at once. This is done by switching the connection destination to the voltage side.

15 and 16, a series of reset operations in which the on-voltage is applied to the lines L <b> 1 to Lx of the scanning line 5 by the first and second methods described above to reset all the radiation detection elements 7. Is repeated a plurality of times to complete the reset process. In FIG. 17, the on-voltage is applied to each of the lines L1 to Lx of the scanning line 5 by the above-described third method so that all the radiation detection elements 7 are Although the case where the reset process is completed by performing a series of reset operations that are reset once is not limited to this, the radiographic image capturing apparatus 1 includes the first to third methods described above. Thus, a series of reset operations for resetting all the radiation detection elements 7 may be performed only once to complete the reset process, or may be repeated a plurality of times to complete the reset process. Composed Even though it may.
Further, as a method for resetting each radiation detection element 7, methods other than the first to third methods described above can be adopted, and a reset process for resetting each radiation detection element 7 is performed by an appropriate method.

<Reset mode>
The control means 22 is configured to shift to the reset mode and start execution of the reset process described above by a predetermined trigger.
Here, in this embodiment, when an operator such as a radiologist operates the input unit of the console 58 to instruct the start of the radiographic image capturing process, an imaging start instruction signal is transmitted from the console 58 and the imaging start is started. When the antenna device 39 receives the instruction signal, a trigger signal is input from the antenna device 39 to the control unit 22, and the control unit 22 performs a reset process for resetting each radiation detection element 7 in accordance with the trigger signal. Although described as transition to the mode, the predetermined trigger is not limited to this. Specifically, for example, when an operator such as a radiographer presses a switch such as the power switch 36 provided on the side surface portion of the radiographic imaging apparatus 1 to instruct the start of radiographic imaging processing, the control is performed from the switch. It is also possible to configure the trigger signal to be input to the means 22.

  And the control means 22 will memorize | store the time ta when the reset process was completed in RAM etc. which comprise the said control means 22, if the reset process which resets each radiation detection element 7 is completed.

In addition, when the reset process for resetting each radiation detection element 7 is completed, the control unit 22 lights or blinks the indicator 37 to notify the operator such as a radiographer of the completion of the reset process.
When the notification is performed by the radiation image capturing apparatus 1, the operator operates the operation switch 56 provided on the console 57 in accordance with the notification to instruct the radiation generation apparatus 52 to start radiation irradiation. . As a result, radiation is emitted from the radiation generation device 52 to the radiographic imaging device 1.

<Charge accumulation mode>
Further, when the reset process for resetting each radiation detection element 7 is completed, the control unit 22 turns off the voltage from the gate driver 15b of the scanning driving unit 15 to all the scanning lines 5, that is, all the lines L1 to Lx of the scanning line 5. Is applied to turn off each TFT 8, thereby making a transition to a charge accumulation mode in which the charges generated in each radiation detection element 7 by radiation irradiation are accumulated in each radiation detection element 7. .
When transitioning to the charge accumulation mode, the control means 22 detects the current flowing through the current detection means 41 in the wiring 15c or the scanning line 5, specifically in the wiring 15c or the scanning line 5 in this embodiment. The voltage value V corresponding to the flowing current is detected, and the voltage value V is monitored.

  Here, as shown in FIG. 18, the voltage value V suddenly increases when radiation irradiation is started (time tb) when radiation irradiation on the radiation incident surface R of the radiation imaging apparatus 1 is started. When the irradiation of radiation is completed, the value decreases rapidly when the irradiation of radiation is completed (time tc).

Therefore, in the present embodiment, when the voltage value V output from the current detection unit 41 increases and exceeds a preset threshold value Vth (see time td in FIG. 18), for example, the radiation generator 52 emits radiation. The control means 22 detects that the irradiation has been started. In addition, when the voltage value V output from the current detection unit 41 decreases and falls below a preset threshold value Vth (see time tf in FIG. 18), for example, the radiation generator 52 ends the radiation irradiation. It is assumed that the control means 22 detects this.
That is, the control unit 22 starts and ends the radiation irradiation based on the value of the current detected by the current detection unit 41, specifically, the voltage value V corresponding to the current in the present embodiment. Can be detected.

  In this embodiment, the threshold used when detecting the start of radiation irradiation and the threshold used when detecting the end of radiation irradiation are described as being the same value Vth. The threshold value used when detecting the start and the threshold value used when detecting the end of radiation irradiation may be different values.

In the present embodiment, the case where the radiation value is started is detected when the voltage value V increases and exceeds a preset threshold value Vth (see time td in FIG. 18). For example, when the voltage value V increases and the rate of increase of the voltage value V exceeds a predetermined threshold value (see time te in FIG. 18), radiation irradiation starts. It is good also as detecting that it was done.
In the present embodiment, the case where the irradiation with radiation is detected is detected when the voltage value V decreases and falls below a preset threshold value Vth (see time tf in FIG. 18). For example, when the voltage value V decreases and the rate of decrease of the voltage value V exceeds a predetermined threshold value (see time tg in FIG. 18), radiation irradiation ends. It is good also as detecting that it was done.

  Note that, even when the radiation image capturing apparatus 1 is not irradiated with radiation, dark charges are generated in each radiation detection element 7 due to thermal excitation of the radiation detection element 7 due to heat or the like, and as shown at time ta in FIG. Even before the radiation imaging apparatus 1 is irradiated with radiation, the current detection means 41 may output a voltage value Va that is a small amount but not 0 [V].

And the control means 22 will memorize | store the time (time td) at the time of detecting the irradiation start of radiation in RAM etc. which comprise the said control means 22, if the irradiation start of radiation is detected.
Further, when detecting the end of radiation irradiation, the control means 22 stores the time (time tf) at the time of detecting the end of radiation irradiation in a RAM or the like constituting the control means 22.

  In addition, the control unit 22 detects the start of radiation irradiation based on the value of the current detected by the current detection unit 41, specifically, the voltage value V corresponding to the current in the present embodiment. It is configured to calculate the radiation dose.

Specifically, the control unit 22 stores at least the voltage value V from the time point (time td) at which the start of radiation irradiation is detected in the RAM or the like among the voltage values V detected by the current detection unit 41. When the end of radiation irradiation is detected, the stored voltage value V is used to detect the end of radiation irradiation (time td) from the time when radiation irradiation start is detected (time td). In the meantime, an integral value of the voltage value V detected by the current detection means 41 is calculated, and based on the calculated integral value, the radiation dose to the radiation imaging apparatus 1 from the time when the start of radiation irradiation is detected is calculated. It is configured to calculate.
Here, the radiographic image capturing apparatus 1 may be configured to perform integration processing of the voltage value V as processing by the control means 22, and for example, an output of the differential amplifier 41 c of the current detection means 41. For example, an integration unit may be provided on the terminal side so that the integration process of the voltage value V is performed by the integration unit. Any known method can be adopted as the method of integration processing.

  At this time, as shown in FIG. 18, there is a case where a very small voltage value Va is output from the current detecting means 41 even when the radiation image capturing apparatus 1 is not irradiated with radiation, and this very small voltage value Va is Even while the radiation image capturing apparatus 1 is irradiated with radiation, the current detection means 41 is considered to output the radiation image capturing apparatus 1 regardless of the radiation irradiation.

Therefore, for example, a temporal average value of the minute voltage value Va is calculated in advance in a state where the radiation imaging apparatus 1 is not irradiated with radiation, and the calculated minute value from the voltage value V output from the current detection means 41 is calculated. It is also possible to perform the integration process using a value obtained by subtracting the temporal average value of the voltage value Va.
With this configuration, a minute voltage value Va associated with dark charge can be excluded, so that the irradiation dose after the start of radiation irradiation can be calculated more accurately.

For example, when a noise component is superimposed on the voltage value V output from the current detection unit 41, for example, the output of the differential amplifier 41c of the current detection unit 41 is used to remove the noise component. Between the terminal and the control means 22, a band pass filter (band pass filter) that passes only data in a predetermined frequency band and does not pass data in other frequencies is additionally arranged. Is also possible. In the case where the integration unit is provided on the output terminal side of the differential amplifier 41c of the current detection unit 41 as described above, the bandpass filter can be provided between the differential amplifier 41c and the integration unit.
With this configuration, the noise component can be removed, so that the irradiation dose after the start of radiation irradiation can be calculated more accurately.

In this embodiment, the radiation irradiation dose is calculated after detecting the end of radiation irradiation. However, the present invention is not limited to this. For example, when the radiation irradiation start is detected, the radiation irradiation dose is calculated. When the calculation of the above is started and the end of radiation irradiation is detected, the calculation can be ended.
In addition, a method other than the integration process can be adopted as a method of calculating the radiation dose, and the radiation dose is calculated by an appropriate method.

Then, the control means 22 notifies the calculated radiation dose to the console 58 via the antenna device 39.
As a result, the radiation dose calculated on the radiation imaging apparatus 1 side is displayed on the display unit 58a of the console 58.

<Read mode>
Further, when the control means 22 detects the end of radiation irradiation, the charge accumulated in the radiation detection element 7 from the radiation detection element 7 to the signal line 6 is applied by applying an ON voltage from the scanning drive means 15 to the scanning line 5. , And the readout circuit 17 converts the emitted charges into image data, thereby making a transition to a readout mode in which an image data readout process for reading out image data from each radiation detection element 7 is performed. .

  Specifically, the control means 22 detects the end of radiation irradiation, and, similarly to the case of sequential resetting, the on-voltage is applied from the gate driver 15b of the scanning drive means 15 to each line L1 to Lx of the scanning line 5. While sequentially switching the application timing, the readout circuit 17 sequentially performs a readout operation to perform image data readout processing for reading out image data from each radiation detection element 7.

  Here, in the present embodiment, for example, as illustrated in FIG. 19, the radiographic image capturing apparatus 1 acquires a dark image for correction for correcting a radiographic image following the radiographic image capturing process. Is configured to do.

As described above, in each radiation detection element 7, a so-called dark charge is constantly generated due to thermal excitation or the like of each radiation detection element 7 itself, and image data read processing for reading out image data from each radiation detection element 7. In this case, dark charges are read out from each radiation detection element 7 in addition to the charges that are the true image data generated by the radiation irradiation, and the image data on which the offset due to the dark charges is superimposed is read out.
Therefore, in this embodiment, the radiographic image capturing apparatus 1 performs dark image acquisition processing subsequent to the radiographic image capturing processing in order to obtain true image data by subtracting the offset due to dark charge from the read image data. The radiation image capturing apparatus 1 is left in a state in which no radiation is applied to the radiation image capturing apparatus 1, and thereafter, offset data (dark image data) due to dark charges is read from each radiation detection element 7. ing.

  Specifically, for example, the control unit 22 starts a radiographic image capturing process in response to a predetermined trigger. First, a transition is made to the reset mode of the radiographic image capturing process, and a reset process for resetting each radiation detection element 7 is performed (FIG. 19: K1).

Next, when the reset process is completed, the control unit 22 shifts to the charge accumulation mode of the radiographic imaging process at that time (time ta), and charges generated in each radiation detection element 7 are stored in each radiation detection element 7. Accumulate (FIG. 19: K2).
Then, while the radiographic image capturing apparatus 1 is in the charge accumulation mode of the radiographic image capturing process, radiation irradiation to the radiographic image capturing apparatus 1 is started, and the start is detected by the radiographic image capturing apparatus 1. (Time td).

  Next, when the end of radiation irradiation is detected, the control unit 22 transitions to a radiographic imaging reading mode at that time (time tf), and an image data reading process for reading out radiographic image data from each radiation detection element 7. (FIG. 19: K3).

  Next, when the image data reading process ends, the control means 22 ends the radiographic image capturing process at that time and starts the dark image acquisition process. First, a transition is made to a reset mode for dark image acquisition processing, and reset processing for resetting each radiation detection element 7 is performed in the same manner as in the reset mode for radiation image capturing processing (FIG. 19: K1) (FIG. 19). : K4).

Next, when the reset process is completed, the control unit 22 shifts to the charge accumulation mode of the dark image acquisition process at that time (time t1), and is the same as in the charge accumulation mode of the radiographic imaging process (FIG. 19: K2). Thus, the charge generated in each radiation detection element 7 is accumulated in each radiation detection element 7 (FIG. 19: K5).
At this time, while the radiographic image capturing apparatus 1 is in the charge accumulation mode of the dark image acquisition process, no radiation is irradiated from the radiation generating apparatus 52 to the radiographic image capturing apparatus 1. Only dark charges are stored in.

Next, when a predetermined waiting time elapses, the control means 22 shifts to the reading mode of the dark image acquisition process at that time (time t2), and is the same as in the reading mode of the radiographic imaging process (FIG. 19: K3). Thus, image data read processing for reading image data from each radiation detection element 7 is performed (FIG. 19: K6).
At this time, since the charge accumulated in each radiation detection element 7 in the charge accumulation mode of the dark image acquisition process is a dark charge, dark image data is read from each radiation detection element 7 in the read mode of the dark image acquisition process.

  It is also possible to repeatedly execute the steps K4 to K6 a plurality of times and adopt the average value of the dark image data obtained every time as the formal dark image data.

Then, the control means 22 uses the radiographic image data obtained in the radiographic image reading mode (FIG. 19: K3) and the dark image obtained in the dark image acquisition mode (FIG. 19: K6). Data is transmitted from the antenna device 39 to the external device such as the console 58 via the base station 54.
As a result, the console 58 performs, for example, a subtraction process for subtracting the dark image data from the image data of the radiographic image, thereby performing an offset correction process on the image data of the radiographic image.

  Here, the time “t2-t1” for charge accumulation at the time of dark image acquisition processing is set to be the same as the time “tf-ta” for charge accumulation at the time of radiographic image capturing processing, so that the time of dark image acquisition processing In addition, if the TFT 8 is turned off for the same time as that during the radiographic image capturing process, almost the same amount of dark charge as that during the radiographic image capturing process can be accumulated in each of the radiation detecting elements 7. Data can be acquired.

Therefore, in the present embodiment, the time from the time when the reset process is completed (time ta) to the time when the end of radiation irradiation is detected (time tf) is calculated as an accumulation time during the radiographic imaging process, and the calculated radiation The control means 22 is configured to determine the standby time after transition to the charge accumulation mode during the dark image acquisition process, that is, the accumulation time during the dark image acquisition process, based on the accumulation time during the image capturing process. And
Specifically, the control unit 22 calculates, for example, an accumulation time (“tf−ta”) at the time of radiographic imaging processing, and configures the control unit 22 with the calculated accumulation time at the radiographic imaging processing. Stored in a RAM or the like. In the dark image acquisition process, when the elapsed time from the transition to the charge accumulation mode reaches the stored time (“tf−ta”), the control unit 22 transitions to the reading mode. ing.

  Here, in the present embodiment, the dark image acquisition process and the radiographic image capturing process are performed in the same sequence, that is, the time “t2-t1” for charge accumulation in the dark image acquisition process is the same as that in the radiographic image capturing process. In addition to making the time for charge accumulation in “tf-ta” equal, the application timing of the ON voltage and the application time of the ON voltage for each of the lines L1 to Lx of the scanning line 5 are set in the reset mode of the radiographic imaging process. And the reset mode of the dark image acquisition process and the read mode of the radiographic image capturing process and the read mode of the dark image acquisition process. Accordingly, since the radiographic image capturing process can be more accurately reproduced during the dark image acquisition process, more accurate dark image data can be acquired.

  Next, processing related to radiographic imaging by the radiographic imaging apparatus 1 in the radiographic imaging system 50 according to the present embodiment will be described with reference to the flowchart of FIG. 20 and the radiographic imaging system 50 according to the present embodiment will be described. The operation will be described.

  First, the control means 22 of the radiographic image capturing apparatus 1 determines whether or not the antenna apparatus 39 has received an imaging start instruction signal transmitted from the console 58 (step S11).

  If it is determined in step S11 that the antenna device 39 has not received the imaging start instruction signal (step S11; No), the control unit 22 repeats the process of step S11.

  On the other hand, when it is determined in step S11 that the antenna device 39 has received the imaging start instruction signal (step S11; Yes), the control unit 22 transitions to the reset mode and turns on the scanning line 5 from the scanning driving unit 15. By applying a voltage, an extra charge remaining in each radiation detection element 7 is discharged from each radiation detection element 7 to the signal line 6 to start execution of a reset process for resetting each radiation detection element 7 ( Step S12).

  Next, the control means 22 determines whether or not the reset process started in step S12 has been completed (step S13).

  When it is determined in step S13 that the reset process has not been completed (step S13; No), the control unit 22 repeats the process of step S13.

  On the other hand, if it is determined in step S13 that the reset process has been completed (step S13; Yes), the control unit 22 stores the time (time ta) when the reset process is completed in the RAM or the like (step S14). ) And a process of notifying an operator such as a radiographer of the completion of the reset process via the indicator 37 (step S15), and transitions to the charge accumulation mode, and all the scanning lines are transferred from the scanning drive means 15. 5 by applying an off-voltage to each radiation detection element 7, and the current value detected by the current detection means 41, specifically, the voltage value V corresponding to the current in this embodiment. Monitoring is started (step S16).

  Then, in response to the notification of the completion of the reset process (step S15), an operator such as a radiologist operates the operation switch 56 provided on the console 57 to instruct the radiation generator 52 to start radiation irradiation. . As a result, radiation is emitted from the radiation generation device 52 to the radiographic imaging device 1.

  When a signal to start radiation irradiation is transmitted from the radiation generator to the radiographic imaging device, the coordination between the radiographic imaging device and the radiographic generator is not successful, and the signal is transmitted and received accurately. Otherwise, radiation irradiation may be started during the reset process on the radiation imaging apparatus side. In this case, there is a problem that charges generated by radiation irradiation, that is, image data that is useful information about the subject flows out from each radiation detection element in the reset process, and a radiographic image with an appropriate image quality cannot be obtained. It will occur.

  On the other hand, in this embodiment, since the radiographic imaging device 1 is configured to notify the completion of the reset process, even if the radiographic imaging device 1 and the radiation generation device 52 do not cooperate with each other, If an operator such as a radiologist operates the radiation generating device 52 via the operation switch 56 or the like so that radiation irradiation to the radiation image capturing device 1 is started in response to the notification, the radiation image capturing device 1 is surely obtained. After the reset process is completed on the side, radiation irradiation is started. Therefore, it is possible to avoid the start of radiation irradiation while the reset process is being performed on the radiation imaging apparatus 1 side.

  Next, the control means 22 determines whether or not the voltage value V detected by the current detection means 41 has increased and exceeded the threshold value Vth, that is, whether or not the start of radiation irradiation has been detected (step S17).

  When it is determined in step S17 that the start of radiation irradiation has not been detected (step S17; No), the control unit 22 repeats the process of step S17.

  On the other hand, if it is determined in step S17 that the start of radiation irradiation has been detected (step S17; Yes), that is, if it is determined that the voltage value V detected by the current detection means 41 has increased to exceed the threshold value Vth, control is performed. The means 22 stores the time (time td) when the start of radiation irradiation is detected in the RAM or the like (step S18).

  Next, the control means 22 determines whether or not the voltage value V detected by the current detection means 41 has decreased below the threshold value Vth, that is, whether or not the irradiation end of radiation has been detected (step S19).

  If it is determined in step S19 that the end of radiation irradiation has not been detected (step S19; No), the control unit 22 repeats the process of step S19.

  On the other hand, if it is determined in step S19 that the end of radiation irradiation has been detected (step S19; Yes), that is, if it is determined that the voltage value V detected by the current detection means 41 has decreased to fall below the threshold value Vth, control is performed. The means 22 performs a process (step S20) of storing the time (time tf) at the time of detecting the end of radiation irradiation in a RAM or the like (step S20), transitions to the reading mode, and turns on the scanning line 5 from the scanning drive means 15. By applying a voltage, electric charges are discharged from each radiation detection element 7 to the signal line 6 and the read circuit 17 converts the emitted electric charges into image data, thereby starting execution of image data reading processing (step S21). ).

That is, when the control unit 22 transitions to the reading mode, the lines L1 to Lx of the scanning line 5 to which the ON voltage is applied from the gate driver 15b of the scanning driving unit 15 are sequentially switched as shown in FIG. Every time, the image data reading process shown in FIG. 12 is periodically repeated.
Specifically, the charge reset switch 18c of the amplifier circuit 18 is turned on while sequentially switching the timing at which the TFT 8 is turned on by applying the on voltage to the lines L1 to Lx of the scanning line 5 from the scanning drive unit 15. The transmission of the pulse signals Sp1 and Sp2 to / off and the correlated double sampling circuit 19 is periodically repeated.

  Next, the control means 22 is detected by the current detection means 41 between the time point when the radiation start is detected in step S17 (time td) and the time point when the radiation end is detected in step S19 (time tf). Based on the measured voltage value V, the radiation dose to the radiographic imaging device 1 from the time when the radiation start is detected is calculated (step S22), and the calculated radiation dose is output from the antenna device 39. To the console 58 via the base station 54. As a result, the radiation dose calculated on the radiation imaging apparatus 1 side is displayed on the display unit 58a of the console 58.

  When radiation irradiation of the radiation image capturing apparatus 1 is started by the radiation generating apparatus 52, in the radiation image capturing apparatus 1, the radiation incident on the radiation incident surface R is converted into electromagnetic waves such as visible light by the scintillator 3 and converted. The electromagnetic wave reaches the i layer 76 of the radiation detection element 7 immediately below, and an electron-hole pair is 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. For this reason, the potential on the first electrode 74 side decreases, and accordingly, the potential on the source electrode 8s side of the TFT 8 connected to the first electrode 74 side of the radiation detection element 7 decreases.

  In the TFT 8, a kind of capacitor-like structure is formed by the gate electrode 8g, the source electrode 8s, and the insulating layer 71 formed therebetween, and a parasitic capacitance is formed between the gate electrode 8g and the source electrode 8s. Is present. A predetermined off voltage is applied to the gate electrode 8g of the TFT 8 and the potential is fixed. On the other hand, since the potential on the source electrode 8s side of the TFT 8 is lowered, the gate electrode 8g and the source electrode 8s of the TFT 8 are reduced. The potential difference between and changes.

  Therefore, the electric charge corresponding to the change in potential difference is supplied from the power supply circuit 15a of the scanning drive means 15 to each scanning line 5 via the wiring 15coff and the gate driver 15b, and is supplied to the gate electrode 8g portion of each TFT 8. . Therefore, a current flows in the scanning line 5 and the wiring 15coff.

  Further, as shown in FIG. 11, all the scanning lines 5 to which the off voltage is applied are all connected to the wiring 15coff that supplies the off voltage from the power supply circuit 15a to the gate driver 15b via the gate driver 15b of the scanning driving means 15. It is connected. Therefore, since a current corresponding to the total amount of current flowing through each scanning line 5 flows in the wiring 15coff, it becomes a relatively large current, and the voltage value V (or the current) corresponding to the current flowing along with radiation irradiation. Can be easily detected.

  Further, when radiation irradiation to the radiation image capturing apparatus 1 is completed by the radiation generator 52, the radiation image capturing apparatus 1 does not generate a new electron-hole pair in each radiation detection element 7, and the first electrode The potential difference between 74 and the second electrode 78 does not change. Even in the TFT 8, the potential difference between the gate electrode 8g and the source electrode 8s does not change. For this reason, the current flowing through each scanning line 5 and the wiring 15coff stops flowing, and the voltage value V detected by the current detection means 41 decreases after the radiation irradiation ends, and the radiation detection element 7 It returns to the original voltage value Va caused by dark charges or the like generated in each radiation detection element 7 due to thermal excitation by heat.

In this way, by detecting the voltage value V corresponding to the current flowing through the scanning line 5 and the wiring 15coff by the current detection means 41, it is detected that the radiation irradiation has started or the radiation irradiation has been completed. It becomes possible to do.
Further, since the voltage value V detected by the current detection means 41 increases and decreases in this way in conjunction with the irradiation of radiation, the radiation dose irradiated to the radiation imaging apparatus 1 is determined based on the voltage value V. It is also possible to calculate.

Further, in this way, the radiographic imaging apparatus 1 detects the voltage value V corresponding to the current flowing through the scanning line 5 and the wiring 15coff by the current detection unit 41, and detects the end of radiation irradiation. Even without cooperation with the generating device 52, the charge accumulation mode can be quickly changed to the reading mode.
When the radiation mode is not finished and the transition to the reading mode is not completed, the state of the charge accumulation mode during the radiographic image capturing process becomes long, and the timing for starting the dark image acquisition process is delayed. In this case, the temperature conditions and the like change between the radiographic image capturing process and the dark image acquiring process, and the offset due to the dark charge contained in the image data acquired by the radiographic image capturing process and the dark image acquiring process There is a large difference between the acquired dark image data, that is, offset data, and the image data cannot be corrected accurately, resulting in a problem that a radiographic image with an appropriate image quality cannot be obtained.

  On the other hand, in the present embodiment, the radiographic imaging device 1 can quickly transition from the charge accumulation mode to the readout mode by detecting the end of radiation irradiation, so the state of the charge accumulation mode is useless. It is avoided that it becomes long. Therefore, since the temperature conditions and the like can be made close during the radiographic image capturing process and the dark image acquiring process, the offset due to the dark charge contained in the image data acquired by the radiographic image capturing process and the dark image acquisition There is no significant difference between the dark image data acquired by the processing, that is, offset data, and the image data can be corrected accurately.

Further, as in the present embodiment, when the radiographic image capturing process and the dark image acquisition process are performed in the same sequence in order to obtain more accurate dark image data, the dark image acquisition is performed when the charge accumulation mode of the radiographic image capturing becomes long. The charge accumulation mode of the process also becomes longer, and there is a problem that the time from the start of the radiographic image capturing process to the end of the dark image acquisition process becomes longer.
On the other hand, in the present embodiment, it is avoided that the state of the charge accumulation mode in radiographic imaging is unnecessarily long, so that it is also avoided that the charge accumulation mode of the dark image acquisition process is long. The time from the start of the radiographic image capturing process to the end of the dark image acquisition process can be shortened.

  Note that, as in the present embodiment, when the current detection unit 41 is provided and the voltage value V (or the current) corresponding to the current flowing through the scanning line 5 and the wiring 15coff is detected, the current detection unit is used as the bias line. 9 and the connection 10, noise is generated in the current detecting means 41 and applied to each scanning line 5 from the power supply circuit 15 a of the scanning driving means 15 through the gate driver 15 b, and is applied to each TFT 8. The noise generated in the current detection means 41 is superimposed on the off voltage applied to the gate electrode 8g.

  However, when the current detecting means is provided on the bias line 9, the noise of the voltage generated by the current detecting means is amplified by the relatively large parasitic capacitance of the radiation detecting element to become a relatively large noise charge, which is irradiated with radiation. As a result, it is superimposed on the charge generated in the radiation detection element, resulting in a problem that the image quality of the finally obtained radiographic image, particularly the granularity thereof, deteriorates.

  By the way, as shown in FIG. 6, the area of the portion where the source electrode 8s and the gate electrode 8g of the TFT 8 overlap is very small as compared with the area of the condensing surface of the photodiode constituting the radiation detection element 7. For this reason, the parasitic capacitance in the photodiode portion of the radiation detection element 7 is increased, whereas the parasitic capacitance in the portion constituted by the source electrode 8s and the gate electrode 9g of the TFT 8 is very small.

Therefore, when the current detection unit 41 is provided in the wiring 15c that connects the power supply circuit 15a and the gate driver 15b of the scan driving unit 15 as in the present embodiment, the parasitic noise in the voltage generated by the current detection unit 41 is very small. The capacitance is amplified only very slightly, and the generated noise charge is very small.
Then, a minute noise charge generated in the portion where the source electrode 8s and the gate electrode 8g of the TFT 8 overlap is transmitted to the radiation detection element 7 side, and the charge generated in the photodiode portion of the radiation detection element 7 due to radiation irradiation. Even if they are superimposed, the effect is very small compared to the conventional case.

  For this reason, in the present embodiment, the noise generated in the current detection unit 41 is superposed on the charge generated in each radiation detection element 7 by irradiation of radiation, that is, the noise generated in the current detection unit 41 is superposed on the image data. Therefore, the occurrence of problems such as deterioration of the image quality of the finally obtained radiographic image, particularly the granularity thereof, can be avoided.

  In addition, when the current detection means is provided on the bias line 9, it is necessary to apply on-voltages to some scanning lines when transitioning to the charge accumulation mode in order to detect the end of radiation irradiation. . As a result, the switch means (TFT) connected to the scanning line to which the ON voltage is applied is turned on, and the charge generated by radiation irradiation, that is, image data flows out from the radiation detection element connected to the TFT in the ON state. As a result, a line defect occurs. Although line defects are corrected later, it is difficult to accurately correct such line defects.

  On the other hand, when the current detection means 41 is provided in the wiring 15c connecting the power supply circuit 15a and the gate driver 15b of the scanning driving means 15 as in the present embodiment, the scanning line 5 is changed when the mode is changed to the charge accumulation mode. Since the end of radiation irradiation can be detected without applying an on-voltage, problems such as a line defect occurring in the finally obtained radiation image can be avoided.

  Next, the control means 22 is based on the time (time ta) when the reset process stored in step S14 is completed and the time (time tf) when the end of radiation irradiation detected in step S20 is detected. An accumulation time (“tf−ta”) at the time of the radiographic image capturing process is calculated, and the standby after the transition to the charge accumulation mode at the time of the dark image acquisition process is performed based on the calculated accumulation time at the radiographic image capturing process. Time "t2-t1" is determined (step S24). Specifically, the control unit 22 determines the standby time “t2-t1” so that the standby time “t2-t1” is the same as the accumulation time “tf-ta” at the time of radiographic image capturing processing.

  Next, the control means 22 determines whether or not the image data reading process started in step S21 is completed (step S25).

  When it is determined in step S25 that the image data reading process started in step S21 has not been completed (step S25; No), the control unit 22 repeatedly performs the process of step S25.

  On the other hand, if it is determined in step S25 that the image data reading process started in step S21 has been completed (step S25; Yes), the control unit 22 proceeds to the dark image acquisition process (step S26), and performs this process. finish.

  In the dark image acquisition process, the control unit 22 first shifts to the reset mode and starts executing the reset process for resetting each radiation detection element 7.

  Next, when the reset process is completed, the control unit 22 shifts to the charge accumulation mode, and accumulates charges (dark charges) generated in each radiation detection element 7 in each radiation detection element 7.

  Next, when the elapsed time from the transition to the charge accumulation mode reaches the standby time “t2-t1” determined in step S24 (= accumulation time “tf-ta” at the time of radiographic imaging processing), the control unit 22 Transits to a reading mode and reads dark image data from each radiation detection element 7.

  Next, when the reading of the dark image data from each radiation detection element 7 is completed, the control means 22 reads the image data of the radiation image read out in the radiation image photographing process (FIG. 20) and the dark data read out in the dark image acquisition process. The image data is transmitted to the console 58 via the antenna device 39, and the dark image acquisition process is terminated.

  Here, in the present embodiment, the accumulation time “tf-ta” at the time of radiographic image capturing processing and the standby time “t2-t1” after transition to the charge accumulation mode at the time of dark image acquisition processing are the same. As described above, the standby time “t2-t1” is determined based on the accumulation time “tf-ta”. Therefore, during the dark image acquisition process, substantially the same amount of dark charge as that during the radiographic image capturing process can be accumulated in each radiation detection element 7, so that a more accurate correction dark image can be obtained.

  In order to obtain a more accurate correction dark image by the dark image acquisition process, it is preferable that the temperature conditions and the like are close between the radiographic image capturing process and the dark image acquisition process. In the present embodiment, since the radiographic imaging device 1 can detect the end of radiation irradiation and promptly transition from the charge accumulation mode to the readout mode, the radiographic imaging process and the dark image acquisition process As a result, the temperature conditions and the like become close, and a more accurate dark image for correction can be obtained.

  According to the radiographic image capturing system 50 and the radiographic image capturing device 1 in the first embodiment described above, the radiographic image capturing device 1 is configured to notify the completion of the reset process for resetting the radiation detecting element 7. ing.

  As described above, when a signal indicating that radiation irradiation is started is transmitted from the radiation generator to the radiographic image capturing apparatus, the cooperation between the radiographic image capturing apparatus and the radiation generating apparatus is not successful, and the signal If transmission and reception are not performed accurately, radiation irradiation may be started during the reset process on the radiation imaging apparatus side. In this case, the charge generated by the irradiation of radiation, that is, the image data flows out from each radiation detection element in the reset process, and there arises a problem that a radiation image having an appropriate image quality cannot be obtained.

  On the other hand, in this embodiment, since the radiographic imaging device 1 is configured to notify the completion of the reset process, even if the radiographic imaging device 1 and the radiation generation device 52 do not cooperate with each other, If an operator such as a radiologist operates the radiation generating device 52 via the operation switch 56 or the like so that radiation irradiation to the radiation image capturing device 1 is started in response to the notification, the radiation image capturing device 1 is surely obtained. After the reset process is completed on the side, radiation irradiation is started. Therefore, it is possible to avoid the start of radiation irradiation during the reset process on the radiation image capturing apparatus 1 side, and it is possible to obtain a radiation image with an appropriate image quality.

  In addition, the radiographic imaging apparatus 1 includes a current detection unit 41 that detects a current flowing through the wiring 15c connecting the power supply circuit 15a and the gate driver 15b or a current flowing through the scanning line 5, on the scanning line 5 side, specifically, Provided in the wiring 15c connecting the power supply circuit 15a and the gate driver 15b, the end of radiation irradiation or the like is based on the value of the current detected by the current detection means 41, specifically, the voltage value V corresponding to the current. It is configured so that it can be detected.

  As described above, when the current detection unit is provided on the bias line 9, the noise of the voltage generated by the current detection unit is amplified by a relatively large parasitic capacitance of the radiation detection element, and becomes a relatively large noise charge. When the radiation is superimposed on the charge generated in the radiation detecting element, the quality of the finally obtained radiographic image, particularly the granularity thereof, deteriorates.

  On the other hand, when the current detection means 41 is provided on the scanning line 5 side, specifically, the wiring 15c connecting the power supply circuit 15a and the gate driver 15b of the scanning drive means 15 as in this embodiment, the current detection means 41 is provided. The noise of the voltage generated in (1) is amplified only very slightly by a very small parasitic capacitance, and the generated noise charge is very small. For this reason, since the noise generated by the current detection unit 41 is only slightly superimposed on the charge generated in each radiation detection element 7 by irradiation of radiation, that is, image data, the influence of the noise generated by the current detection unit 41 is reduced. It becomes possible. Therefore, it is possible to avoid problems such as deterioration of the image quality of the finally obtained radiographic image, particularly the granularity thereof, and it is possible to acquire a radiographic image having an appropriate image quality.

  Further, as described above, when the current detection means is provided on the bias line 9, an on-voltage is applied to several scanning lines when transitioning to the charge accumulation mode in order to detect the end of radiation irradiation. I have to keep it. As a result, the switch means (TFT) connected to the scanning line to which the ON voltage is applied is turned on, and the charge generated by radiation irradiation, that is, image data flows out from the radiation detection element connected to the TFT in the ON state. As a result, a line defect occurs. Although line defects are corrected later, it is difficult to accurately correct such line defects.

  On the other hand, when the current detection unit 41 is provided on the scanning line 5 side, specifically, the wiring 15c connecting the power supply circuit 15a and the gate driver 15b of the scanning driving unit 15 as in the present embodiment, charge accumulation is performed. Since it is possible to detect the end of radiation irradiation without applying an on-voltage to the scanning line 5 when the mode is changed, problems such as a line defect occurring in the finally obtained radiation image are avoided. Therefore, it is possible to acquire a radiographic image having an appropriate image quality.

  The radiographic image capturing apparatus 1 is configured to shift to a reading mode when the end of radiation irradiation is detected.

  As described above, when the irradiation is not completed and the transition to the reading mode is not completed, the state of the charge accumulation mode during the radiographic image capturing process becomes long, and the timing for starting the dark image acquisition process is delayed. End up. In this case, the temperature conditions and the like change between the radiographic image capturing process and the dark image acquiring process, and the offset due to the dark charge contained in the image data acquired by the radiographic image capturing process and the dark image acquiring process There is a large difference between the acquired dark image data, that is, offset data, and the image data cannot be corrected accurately, causing problems such as failure to obtain a radiographic image with an appropriate image quality.

  On the other hand, in the present embodiment, the radiographic imaging device 1 can quickly transition from the charge accumulation mode to the readout mode without detecting the radiation irradiation end, even if the radiation imaging device 1 does not cooperate. Therefore, it is avoided that the state of the charge accumulation mode becomes unnecessarily long. Therefore, since the temperature conditions and the like can be made close during the radiographic image capturing process and the dark image acquiring process, the offset due to the dark charge contained in the image data acquired by the radiographic image capturing process and the dark image acquisition There is no significant difference between the dark image data acquired by the processing, that is, the offset data, and the image data can be accurately corrected, and a radiographic image with an appropriate image quality can be acquired.

In addition, when the radiographic image capturing process and the dark image acquiring process are performed in the same sequence in order to obtain more accurate dark image data as in the present embodiment, the state of the charge accumulation mode during the radiographic image capturing process becomes long. In addition, the charge accumulation mode of the dark image acquisition process becomes longer, and there is a problem that the time from the start of the radiation image capturing process to the end of the dark image acquisition process becomes longer.
On the other hand, in this embodiment, since the state of the charge accumulation mode during the radiographic image capturing process is avoided from being unnecessarily long, the charge accumulation mode of the dark image acquisition process is also prevented from becoming long. The time from the start of the radiographic image capturing process to the end of the dark image acquisition process can be shortened.

In the present embodiment, the radiation dose from the time point when the radiation start is detected is calculated based on the value of the current detected by the current detector 41, specifically, the voltage value V corresponding to the current. Then, the calculated radiation dose is notified to the console 58 via the antenna device 39, and the console 58 is configured to display the notified radiation dose on the display unit 58a.
Therefore, a radiographer, a doctor, or the like can grasp the radiation dose irradiated from the radiation generator 52 to the radiographic imaging device 1.

In the present embodiment, the radiographic image capturing apparatus 1 is configured to perform dark image acquisition processing for acquiring a correction dark image for correcting a radiographic image, following the radiographic image capturing processing. The radiographic image capturing apparatus 1 calculates, as an accumulation time, a time from the time when the reset process at the time of the radiographic image capturing process is completed to the time when the end of radiation irradiation is detected, and the calculated accumulation time (“tf−ta”). )), The standby time (“t2-t1”) after the transition to the charge accumulation mode during the dark image acquisition process is determined.
Specifically, the radiographic imaging device 1 has an accumulation time “tf-ta” at the time of radiographic imaging processing and a standby time “t2-t1” after the transition to the charge accumulation mode at the time of dark image acquisition processing. Are set to be the same, the standby time “t2-t1” is determined based on the accumulation time “tf-ta”. Therefore, during the dark image acquisition process, substantially the same amount of dark charge as that during the radiographic image capturing process can be accumulated in each radiation detection element 7, so that a more accurate correction dark image can be obtained.

[Second Embodiment]
Next, a radiographic image capturing system and a radiographic image capturing apparatus according to the second embodiment will be described.
In the radiographic image capturing system 50 and the radiographic image capturing apparatus 1 according to the second embodiment, the control unit 22 of the radiographic image capturing apparatus 1 detects the current value detected by the current detecting unit 41 (specifically, In the first embodiment, instead of detecting the end of radiation irradiation or the like based on the voltage value V) corresponding to the current, the radiation is based on the data read by the readout circuit 17 (leak data Dleak). This is different from the radiographic image capturing system 50 and the radiographic image capturing apparatus 1 of the first embodiment in that the end of irradiation is detected. Therefore, below, only a different part from 1st Embodiment is demonstrated, and another common part attaches | subjects the same code | symbol and abbreviate | omits description.

Here, first, the leak data Dleak will be described.
When the off voltage is applied to all the lines L1 to Lx of the scanning line 5 from the scanning drive unit 15 and each TFT 8 is in the off state, the charge generated in each radiation detecting element 7 is the radiation detecting element 7. However, due to the characteristics of the TFT, as shown in FIG. 21, even if each TFT 8 is in an OFF state, each charge q from each radiation detection element 7 through each TFT 8 is slightly transferred to the signal line 6. To leak.

Then, each charge q leaked from each radiation detection element 7 flows through the signal line 6 and flows into the capacitor 18b of the amplifier circuit 18 to be accumulated.
Further, in the amplifier circuit 18, since a voltage value corresponding to the amount of charge accumulated in the capacitor 18b is output from the output side of the operational amplifier 18a, the charge reset switch 18c is turned off and then output from the amplifier circuit 18. As shown in FIG. 13, the correlated double sampling circuit 19 outputs the difference “Vfi−Vin” between the voltage values Vin and Vfi held according to the pulse signals Sp1 and Sp2 as leak data Dleak. .

  As described above, the total value of the charges q leaked from the radiation detection elements 7 connected to the single signal line 6 via the TFTs 8 is accumulated in the capacitor 18b of the amplifier circuit 18 and leaked. Data corresponding to the total value of each charge q is converted and read as leak data Dleak for each readout circuit 17.

  Furthermore, when the TFT 8 serving as the switch means is irradiated with radiation or when an electromagnetic wave converted from radiation is irradiated by the scintillator 3 as in the present embodiment, the amount of leakage current flowing through the TFT 8 increases. It is known. This is thought to be because electron-hole pairs are newly generated in the semiconductor layer 82 of the TFT 8 when the TFT 8 is irradiated with radiation (or electromagnetic waves converted from the radiation).

  When radiation irradiation starts, the amount of leakage current flowing in each TFT 8 increases, and when the amount of charge q leakage from each radiation detection element 7 via each TFT 8 increases, one signal line 6, the total value of each charge q leaking from each radiation detecting element 7 connected to 6 increases, and the value of the corresponding leak data Dleak also increases.

  On the other hand, when radiation irradiation ends, the amount of leakage current flowing in each TFT 8 returns to the original dark amount, and when the amount of leakage of charge q from each radiation detection element 7 via each TFT 8 decreases, 1 The total value of each charge q leaking from each radiation detection element 7 connected to the signal line 6 decreases, and the value of the corresponding leak data Dleak also decreases.

  Therefore, when the leakage data reading process for reading out the leakage data Dleak from each radiation detection element 7 is periodically repeated and the read leakage data Dleak is plotted in time series, for example, as shown in FIG. When the radiation generator 52 starts irradiating the radiation incident surface R of the radiation image capturing apparatus 1 with the radiation generator 52, the value of the data Dleak increases abruptly when the radiation irradiation starts (time tb). When the irradiation of is completed, it rapidly decreases at the time when radiation irradiation is completed (time tc).

Therefore, in the present embodiment, when the control unit 22 transitions to the charge accumulation mode, the control circuit 22 causes the read circuit 17 to periodically and repeatedly perform a leak data read process for reading the leak data Dleak from each radiation detection element 7, and the leak data Dleak. Start monitoring the value of.
Then, when the value of the read leak data Dleak increases, for example, when the value exceeds a preset threshold value Dth (see time ti in FIG. 22), the radiation generator 52 has started radiation irradiation. Is detected by the control means 22. In addition, when the value of the read leak data Dleak decreases and falls below a preset threshold value Dth (see time tj in FIG. 22), for example, the radiation generation by the radiation generator 52 is completed. Is configured to be detected by the control means 22.

In this embodiment, the threshold value used when detecting the start of radiation irradiation and the threshold value used when detecting the end of radiation irradiation are described as being the same value Dth. The threshold value used when detecting the start and the threshold value used when detecting the end of radiation irradiation may be different values.
Further, in the present embodiment, it is described that the start of radiation irradiation is detected when the value of the leak data Dleak increases and exceeds a preset threshold value Dth (see time ti in FIG. 22). However, the present invention is not limited to this. For example, when the value of the leak data Dleak increases and the increase rate of the value of the leak data Dleak exceeds a predetermined threshold value set in advance, radiation irradiation is started. This may be detected.
Further, in the present embodiment, when the value of the leak data Dleak decreases and falls below a preset threshold value Dth (see time tj in FIG. 22), it is described as detecting that radiation irradiation has ended. However, the present invention is not limited to this. For example, when the value of the leak data Dleak decreases and the decrease rate of the value of the leak data Dleak exceeds a predetermined threshold value set in advance, the radiation irradiation is terminated. This may be detected.

[Radiation imaging system]
The radiographic image capturing system 50 of the second embodiment is arranged in the radiographing room R1, the front chamber R2, and the outside thereof, like the radiographic image capturing system 50 (see FIG. 1) of the first embodiment. The radiographic image capturing apparatus 1, the console 58, the radiation generating apparatus 52, and the like are provided.

[Radiation imaging equipment]
For example, as shown in FIGS. 23 and 24, the radiographic image capturing apparatus 1 of the second exemplary embodiment includes a power supply circuit 15a and a gate driver of the scanning drive unit 15 in the radiographic image capturing apparatus 1 of the first exemplary embodiment. Although the current detection means 41 is provided in the wiring 15c that connects to 15b, the current detection means 41 is not provided, which is different from the radiographic imaging apparatus 1 of the first exemplary embodiment.
Further, for example, as shown in FIG. 24, the radiographic imaging apparatus 1 of the second exemplary embodiment includes a charge reset switch 18 c between an operational amplifier 18 a of the amplifier circuit 18 and a correlated double sampling circuit 19. The point which is additionally provided with the switch 18e which opens and closes in conjunction is different from the radiographic imaging device 1 of the first exemplary embodiment.

The switch 18e is configured to be turned off in conjunction with the charge reset switch 18c being turned on, and to be turned on in conjunction with the charge reset switch 18c being turned off. ing.
In the following description, only the operation and the like of the charge reset switch 18c will be described, and the operation of the switch 18e may not be described. However, the switch 18e is turned on / off with the charge reset switch 18c without any particular description. Turns on / off in conjunction with.

In the amplification circuit 18, in the image data reading process and the leak data reading process, each radiation detection element is connected via each TFT 8 which is turned on while the charge reset switch 18c is turned off and the switch 18e is turned on. The charge accumulated from 7 is released to the signal line 6 (in the case of image data reading processing), or the charge q leaks to the signal line 6 from each radiation detection element 7 via each TFT 8 which is turned off. When it comes (in the case of leak data read processing), the charge flows through the signal line 6 and flows into the capacitor 18b of the amplifier circuit 18 and is accumulated.
In the amplifier circuit 18, a voltage value corresponding to the amount of charge accumulated in the capacitor 18b is output from the output side of the operational amplifier 18a.

  As in the case of the image data reading process of the first embodiment, as shown in FIG. 12, the control means 22 first starts the charge reset switch 18c of the amplifier circuit 18 of each reading circuit 17 in the image data reading process. To turn it 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, the voltage value output from the amplifier circuit 18, the moment of the charge reset switch 18c in the OFF state, turns the voltage value Vin is changed by the amount of charge due to kTC noise from the reference potential V ₀ which the above-mentioned . At this stage, as shown in FIG. 12, the control means 22 transmits the first pulse signal Sp1 to the correlated double sampling circuit 19, and holds the voltage value Vin output from the amplifier circuit 18 at that time. .

  Subsequently, the control unit 22 applies an ON voltage to one scanning line 5 (for example, the line Ln of the scanning line 5) from the gate driver 15b of the scanning driving unit 15, and the gate electrode 8g is connected to the scanning line 5. The TFT 8 being turned on is turned on (see FIG. 12). Then, the charge accumulated in the radiation detection element 7 from each radiation detection element 7 to which these TFTs 8 are connected flows into the capacitor 18b of the amplifier circuit 18 via each signal line 6 and is accumulated, and is accumulated in the capacitor 18b. The voltage value output from the amplifier circuit 18 increases in accordance with the amount of charge that has been made.

  Next, 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 as shown in FIG. The TFT 8 connected to is turned off. At this stage, the control means 22 transmits the second pulse signal Sp2 to each correlated double sampling circuit 19, and holds the voltage value Vfi output from the amplifier circuit 18 at that time.

  When each correlated double sampling circuit 19 holds the voltage value Vfi by the second pulse signal Sp2, it calculates the difference “Vfi−Vin” of the voltage value, and calculates the calculated difference “Vfi−Vin” as an analog value. The image data is output downstream.

  Further, as in the case of the image data reading process of the first embodiment, the control means 22 is configured so that each of the scanning lines 5 to which the ON voltage is applied from the gate driver 15b of the scanning driving means 15 as shown in FIG. The lines L1 to Lx are sequentially switched, and each time the switching is performed, an image data reading process for reading image data from each of the radiation detection elements 7 is performed.

  On the other hand, in the leakage data reading process, the readout circuit 17 is periodically driven in a state where each TFT 8 is in the OFF state, and the charge q leaked from each radiation detection element 7 through each TFT 8 is stored in the leakage data Dleak. Since the conversion process is performed in a state where each TFT 8 is in an OFF state, an OFF voltage is applied to all the lines L1 to Lx of the scanning line 5 from the scanning driving unit 15 as shown in FIG. That is, unlike the case of the image data reading process shown in FIG. 12, in the leak data reading process, the on / off operation of each TFT 8 is not performed, and at least during the leak data reading process, that is, during the charge accumulation mode. Each TFT 8 is always turned off.

  As shown in FIG. 25, on / off control of the charge reset switch 18c by the control means 22, transmission of the pulse signals Sp1 and Sp2 to the correlated double sampling circuit 19, and the like are in the case of image data reading processing ( 12), as shown in FIG. 13, the amount of charge q leaked from each radiation detection element 7 through each TFT 8 flows into the capacitor 18b of the amplifier circuit 18 and is amplified. The voltage value output from the circuit 18 increases.

  In the case of the leak data reading process, the voltage value output from the amplifier circuit 18 increases. However, the increase in the voltage value in the case of the leak data reading process is usually higher than the degree of increase in the case of the image data reading process. The degree of is small.

Each correlated double sampling circuit 19 calculates the voltage value difference “Vfi−Vin” when the voltage value Vfi is held by the second pulse signal Sp2, as in the case of the image data reading process, and leak data In the case of read processing, the calculated difference “Vfi−Vin” is output downstream as analog value leak data Dleak.
The leak data Dleak output from the correlated double sampling circuit 19 is sequentially transmitted to the A / D converter 20 via the analog multiplexer 21, and is sequentially converted into leak data Dleak having a digital value.

<Reset processing>
The reset process for resetting each radiation detection element 7 by discharging the excess charge remaining in each radiation detection element 7 from each radiation detection element 7 is performed in the same manner as in the first embodiment. Therefore, detailed description is omitted.

<Reset mode>
As in the case of the first embodiment, the control means 22 is configured to transition to the reset mode and to start executing a reset process for resetting each radiation detection element 7 by a predetermined trigger.

  Then, as in the case of the first embodiment, when the reset process for resetting each radiation detection element 7 is completed, the control unit 22 configures the control unit 22 with the time ta when the reset process is completed. The information is stored in a RAM or the like, or the indicator 37 is turned on or blinked to notify the operator such as a radiologist of the completion of the reset process.

<Charge accumulation mode>
Further, as in the case of the first embodiment, when the reset process for resetting each radiation detection element 7 is completed, the control means 22 completes all the scanning lines 5, that is, the scanning lines from the gate driver 15b of the scanning driving means 15. 5, by applying an off voltage to all the lines L <b> 1 to Lx to turn off the TFTs 8, electric charges generated in the radiation detection elements 7 due to radiation irradiation are accumulated in the radiation detection elements 7. It is configured to transition to the accumulation mode.

  When transitioning to the charge accumulation mode, the control unit 22 causes the readout circuit 17 to periodically perform a readout operation, and leaks the charge q leaked from the radiation detection element 7 via the TFT 8 into leak data Dleak. The data reading process is repeatedly performed, the value of the leak data Dleak is monitored, and based on the value of the leak data Dleak read by the reading circuit 17, the start of radiation irradiation and the end of radiation irradiation are detected.

More specifically, the control unit 22 increases the value of the leak data Dleak read by the read circuit 17 and exceeds the threshold value Dth (see time ti in FIG. 22). The start of irradiation is detected, and the end of radiation irradiation by the radiation generator 52 is detected when the value of the leak data Dleak read by the readout circuit 17 decreases and falls below the threshold value Dth (see time tj in FIG. 22). To do.
Then, the control means 22 stores the time (time ti) at the time of detecting the start of radiation irradiation and the time (time tj) at the time of detecting the end of radiation irradiation in a RAM or the like constituting the control means 22. To do.

  Here, as shown in FIG. 21 described above, the leak data Dleak for each read circuit 17 is output from each read circuit 17 as the leak data Dleak. One readout circuit 17 is provided for each signal line 6 provided in the detection unit P at several thousand to several tens of thousands. Therefore, in this embodiment, thousands to tens of thousands of leak data Dleak are output from each read circuit 17 in one leak data read process.

  In the present embodiment, the control means 22 extracts a maximum value from each of the leak data Dleak read for each leak data read process, and determines whether or not the maximum value of the leak data Dleak exceeds the threshold value Dth. It is supposed to be. If comprised in this way, for example, when radiation is irradiated only to the narrow range of the detection part P of the radiographic imaging device 1 (namely, when irradiation is carried out with the irradiation field being narrowed down), radiation is emitted. The leak data Dleak does not increase in the portion that has not been irradiated, but the leak data Dleak increases in the portion that has been irradiated with radiation, but the leak data Dleak corresponding to the portion that has been irradiated with radiation is accurately extracted, It becomes possible to accurately detect the start and end of irradiation.

  Although depending on the nature of each readout circuit 17, if the noise generated in the readout circuit 17 is large, the leaked data Dleak on which the noise is superimposed exceeds the threshold value Dth, erroneously detecting the start of radiation irradiation, etc. May end up. In such a case, for example, the total value (or average value) of the leak data Dleak is calculated for each read IC 16 provided with a predetermined number of read circuits 17, and the total value (or average value) is calculated. It is also possible to extract the maximum value from (1) and compare the maximum value with the threshold value Dth.

  In the read IC 16, a large number of read circuits 17 such as 128 and 256 are usually formed. Therefore, if configured as described above, noise generated in each readout circuit 17 is canceled out when calculating the total value (or average value) of the leak data Dleak. It is possible to reduce the influence on the leak data Dleak.

  Further, in one leak data read process, the total value or average value of each leak data Dleak read by each read circuit 17 is calculated, and the total value or average value is compared with the threshold value Dth. It is also possible to configure as described above.

Further, the control means 22 is configured to calculate the radiation dose from the time when the radiation start is detected based on the value of the leak data Dleak read by the readout circuit 17. The radiation dose can be calculated by calculating an integral value of the leak data Dleak and based on the calculated integral value. The method of calculating the radiation dose is the same as that of the first embodiment. As in the case of the embodiment, a method other than the integration process can be adopted, and the radiation dose is calculated by an appropriate method.
Then, the control means 22 notifies the calculated radiation dose to the console 58 via the antenna device 39.

<Read mode>
Further, as in the case of the first embodiment, when the control unit 22 detects the end of radiation irradiation, the control unit 22 applies an ON voltage to the scanning line 5 from the scanning driving unit 15 to thereby output the signal line 6 from the radiation detecting element 7. The charge accumulated in the radiation detection element 7 is discharged, and the read circuit 17 converts the emitted charge into image data, thereby performing image data read processing for reading image data from each radiation detection element 7. It is configured to transition to the read mode.

  Also in this embodiment, as in the case of the first embodiment, the radiographic image capturing apparatus 1 acquires a dark image for correction for correcting a radiographic image following the radiographic image capturing process. It is comprised so that an acquisition process may be performed.

In the case of the present embodiment, the time from the time when the reset process is completed (time ta) to the time when the end of radiation irradiation is detected (time tj) is calculated as the accumulation time during the radiographic imaging process. Based on the accumulation time at the time of radiographic imaging processing, the control means 22 is configured to determine the standby time “t2−t1” after the transition to the charge accumulation mode at the time of dark image acquisition processing.
Specifically, the control unit 22 calculates, for example, an accumulation time (“tj−ta”) at the time of radiographic imaging processing, and configures the control unit 22 with the calculated accumulation time at the radiographic imaging processing. Stored in a RAM or the like. Then, when the elapsed time from the transition to the charge accumulation mode of the dark image acquisition process reaches the stored time (“tj−ta”), the control unit 22 transitions to the read mode of the dark image acquisition process. It is like that.

  Next, processing related to radiographic imaging by the radiographic imaging apparatus 1 in the radiographic imaging system 50 according to the present embodiment will be described with reference to the flowchart of FIG. 26 and the radiographic imaging system 50 according to the present embodiment. The operation will be described.

  First, the control means 22 of the radiographic image capturing apparatus 1 determines whether or not the antenna apparatus 39 has received an imaging start instruction signal transmitted from the console 58 (step S11), but step S16a shown in the flowchart of FIG. Processes other than S20a are the same as the processes (see FIG. 20) other than steps S16 to S20 of the first embodiment, and thus the description thereof is omitted.

  In step S <b> 16 a, the control unit 22 shifts to the charge accumulation mode, applies an off voltage to all the scanning lines 5 from the scanning driving unit 15, accumulates charges in each radiation detection element 7, and reads out the readout circuit 17. The readout operation is periodically performed so that the leakage data readout processing for converting the charge q leaked from each radiation detection element 7 through the TFT 8 into the leakage data Dleak is repeatedly performed, and the value of the leakage data Dleak is monitored. Is started (step S16a).

That is, when the control means 22 transitions to the charge accumulation mode, the leak data reading process shown in FIG. 25 is periodically repeated.
More specifically, the charge reset switch 18c of the amplifier circuit 18 is turned on / off in a state where the TFT 8 is turned off by applying an off voltage to all the lines L1 to Lx of the scanning line 5 from the scanning drive unit 15. The transmission of the pulse signals Sp1 and Sp2 to the correlated double sampling circuit 19 is periodically repeated.

  Next, the control means 22 determines whether or not the value of the leak data Dleak read by the read circuit 17 has increased and exceeded the threshold value Dth, that is, whether or not the start of radiation irradiation has been detected (step S17a). .

  If it is determined in step S17a that the start of radiation irradiation has not been detected (step S17a; No), the control unit 22 repeats the process of step S17a.

  On the other hand, when it is determined in step S17a that the start of radiation irradiation has been detected (step S17a; Yes), that is, when it is determined that the value of the leak data Dleak read by the reading circuit 17 has increased to exceed the threshold value Dth. The control means 22 stores the time (time ti) at the time of detecting the start of radiation irradiation in the RAM or the like (step S18a).

  Next, the control means 22 determines whether or not the value of the leak data Dleak read by the read circuit 17 has decreased below the threshold value Dth, that is, whether or not the end of radiation irradiation has been detected (step S19a). .

  If it is determined in step S19a that the end of radiation irradiation has not been detected (step S19a; No), the control unit 22 repeats the process of step S19a.

  On the other hand, when it is determined in step S19a that the end of radiation irradiation has been detected (step S19a; Yes), that is, when it is determined that the value of the leak data Dleak read by the readout circuit 17 has decreased to fall below the threshold value Dth. The control means 22 performs a process (step S20a) for storing the time (time tj) at the time when the end of radiation irradiation is detected in the RAM or the like, and proceeds to the process of step S21.

During the leak data reading process, the off-voltage is applied to all the lines L1 to Lx of the scanning line 5 from the scanning drive means 15, and each TFT 8 is in an off state, and therefore it is generated in each radiation detection element 7. However, due to the characteristics of the TFTs, the charges q are slightly transferred from the radiation detection elements 7 to the signal lines 6 through the TFTs 8 even when the TFTs 8 are turned off. To leak.
As described above, in the leak data reading process, the total value of each charge q leaked from each radiation detection element 7 connected to one signal line 6 through each TFT 8 is accumulated in the capacitor 18 b of the amplifier circuit 18. Then, data corresponding to the total value of the leaked charges q is converted and read for each readout circuit 18 as leak data Dleak.

  Then, when radiation irradiation to the radiation image capturing apparatus 1 is started by the radiation generating device 52, in the radiation image capturing apparatus 1, the radiation incident on the radiation incident surface R is converted into electromagnetic waves such as visible light by the scintillator 3, By irradiating the TFT 8 with the electromagnetic wave, for example, electron-hole pairs are newly generated in the semiconductor layer 82 of the TFT 8. Therefore, when the amount of leakage current flowing in each TFT 8 increases and the amount of leakage of charge q from each radiation detection element 7 via each TFT 8 increases, each radiation detection connected to one signal line 6 is detected. The total value of the charges q leaking from the element 7 increases, and the corresponding leak data Dleak also increases.

  Further, when radiation irradiation to the radiation image capturing apparatus 1 is completed by the radiation generating apparatus 52, in the radiation image capturing apparatus 1, for example, new electron-hole pairs are not generated in the semiconductor layer 82 of the TFT 8. Therefore, when the amount of leak current flowing in each TFT 8 returns to the original dark amount, and the leak amount of charge q from each radiation detection element 7 via each TFT 8 returns to the original dark amount, 1 The total value of each charge q leaking from each radiation detection element 7 connected to the signal line 6 returns to the dark value, and the corresponding leak data Dleak also returns to the dark value.

In this way, the charge q leaked from the radiation detection element 7 via the TFT 8 is converted into the leakage data Dleak by the readout circuit 17 and read out, whereby the radiation irradiation is started or the radiation irradiation is performed. It is possible to detect the termination.
Further, since the value of the leak data Dleak read out by the readout circuit 17 increases and decreases in this way, the value of the radiation irradiated to the radiation image capturing apparatus 1 is based on the value of the leak data Dleak. It is also possible to calculate the dose.

Further, in this way, the radiographic imaging device 1 detects the end of radiation irradiation based on the value of the leak data Dleak read by the readout circuit 17, so that the end of radiation irradiation and the like are detected. There is no need to provide current detection means.
Particularly when the current detection means is provided on the bias line 9, the noise generated by the current detection means is superimposed on the charge generated in the radiation detection element due to the irradiation of the radiation, and the image quality of the finally obtained radiographic image. In particular, there is a problem that the graininess deteriorates.
On the other hand, when configured to detect the end of radiation irradiation based on the value of the leak data Dleak read by the readout circuit 17 as in the present embodiment, the end of radiation irradiation is detected. Therefore, it is not necessary to provide a current detection means, so that the voltage noise generated by the current detection means is not superimposed on the charge generated in each radiation detection element, that is, the image data due to radiation irradiation, and finally, Occurrence of problems such as deterioration of the image quality of the obtained radiographic image, in particular its graininess, is avoided.

  Since other points are the same as those shown in the first embodiment, description thereof is omitted.

  According to the radiographic image capturing system 50 and the radiographic image capturing apparatus 1 in the second embodiment described above, the radiographic image capturing apparatus 1 uses the readout circuit 17 provided in the normal radiographic image capturing apparatus, and switches The charge q leaked from the radiation detection element 7 through the TFT 8 as means is read as leak data, and the end of radiation irradiation or the like can be detected based on the leak data.

  As described above, when the current detection means is provided on the bias line 9, the voltage noise generated by the current detection means is superposed on the charge generated in the radiation detection element due to the irradiation of the radiation. Therefore, there is a problem that the image quality of the radiation image obtained, particularly the graininess, is deteriorated.

  On the other hand, when configured to detect the end of radiation irradiation based on the value of the leak data Dleak read by the readout circuit 17 as in the present embodiment, the end of radiation irradiation is detected. For this reason, since it is not necessary to provide a current detection unit, noise of a voltage generated by the current detection unit is not superimposed on charges generated in each radiation detection element, that is, image data, by irradiation of radiation. Therefore, the occurrence of problems such as deterioration of the image quality of the finally obtained radiographic image, particularly the granularity thereof is avoided, and it is possible to acquire a radiographic image having an appropriate image quality.

  Further, as described above, when the current detection means is provided on the bias line 9, an on-voltage is applied to several scanning lines when transitioning to the charge accumulation mode in order to detect the end of radiation irradiation. I have to keep it. As a result, the switch means (TFT) connected to the scanning line to which the ON voltage is applied is turned on, and the charge generated by radiation irradiation, that is, image data flows out from the radiation detection element connected to the TFT in the ON state. As a result, a line defect occurs. Although line defects are corrected later, it is difficult to accurately correct such line defects.

  On the other hand, when configured to detect the end of radiation irradiation based on the value of the leak data Dleak read by the readout circuit 17 as in the present embodiment, the transition to the charge accumulation mode is performed. Since it is possible to detect the end of radiation irradiation without applying an on-voltage to several scanning lines 5, it is possible to avoid the occurrence of problems such as the occurrence of line defects in the finally obtained radiation image. It is possible to acquire a radiographic image with a high image quality.

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

DESCRIPTION OF SYMBOLS 1 Radiographic imaging device 5 Scanning line 6 Signal line 7 Radiation detection element 8 TFT (switch means)
15 Scanning drive means 15a Power supply circuit 15b Gate driver 15c Wiring 17 Reading circuit 22 Control means 37 Indicator (notification means)
39 Antenna device (communication means)
41 current detection means 50 radiation imaging system 52 radiation generator 58 console 58a display unit r region q charge P detection unit Vth, Dth threshold

Claims (7)

A radiation image capturing apparatus that performs a radiation image capturing process, a console that performs predetermined image processing on image data of the radiation image captured by the radiation image capturing apparatus, and irradiating the radiation image capturing apparatus with radiation In a radiographic imaging system comprising a radiation generator,
The radiographic image capturing apparatus includes:
A plurality of scanning lines and a plurality of signal lines arranged so as to cross each other, and a plurality of radiation detection elements arranged in a two-dimensional manner in each region partitioned by the plurality of scanning lines and the plurality of signal lines A detection unit comprising:
When each of the radiation detection elements is arranged and connected, the off-state is applied to the connected scanning line, and the on-state is applied when the on-voltage is applied to the connected scanning line. Then, the switch means for accumulating the charge generated in the radiation detection element in the radiation detection element, and releasing the charge from the radiation detection element to the signal line in the ON state,
A scan driver comprising: a gate driver that switches a voltage applied to the scan line between the on voltage and the off voltage; and a power supply circuit that supplies the on voltage and the off voltage to the gate driver;
A readout circuit that performs an image data readout process of reading out the image data from the radiation detection element by converting the charge emitted from the radiation detection element into the image data;
Current detection means for detecting a current flowing through a wiring connecting the power supply circuit and the gate driver, or a current flowing through the scanning line;
Informing means for informing completion of a reset process for resetting the radiation detection element;
Control means for controlling at least the scanning drive means, the readout circuit and the notification means;
With
The control means includes
Initiating execution of the reset process for releasing the electric charge from the radiation detection element by resetting the radiation detection element by applying the on-voltage to the scanning line from the scanning drive unit by a predetermined trigger,
When the reset process is completed, the completion of the reset process is notified via the notification means, and the off-voltage is applied to all the scanning lines from the scanning drive means, thereby the charge in the radiation detection element. Transition to charge accumulation mode to accumulate
When transitioning to the charge accumulation mode, when the value of the current detected by the current detection means decreases and falls below a predetermined threshold, the end of radiation irradiation by the radiation generator is detected,
When the end of irradiation of the radiation is detected, the charge is discharged from the radiation detection element by applying the ON voltage to the scanning line from the scanning drive unit, and the discharged charge is output to the image reading circuit. A radiographic imaging system, wherein the image data reading process is changed to a reading mode for performing the image data reading process by converting the data into data. The radiographic image capturing apparatus includes a communication unit that transmits the image data to the console.
The control means includes
When transitioning to the charge accumulation mode, when the value of the current detected by the current detection means increases and exceeds a predetermined threshold, the radiation start by the radiation generator is detected,
Based on the value of the current detected by the current detection means, the radiation dose from the time when the radiation start is detected is calculated, and the calculated radiation dose is calculated via the communication means. Notify the console,
The radiographic imaging system according to claim 1, wherein the console includes a display unit capable of displaying an irradiation dose of the radiation notified through the communication unit. A radiation image capturing apparatus that performs a radiation image capturing process, a console that performs predetermined image processing on image data of the radiation image captured by the radiation image capturing apparatus, and irradiating the radiation image capturing apparatus with radiation In a radiographic imaging system comprising a radiation generator,
The radiographic image capturing apparatus includes:
A plurality of scanning lines and a plurality of signal lines arranged so as to cross each other, and a plurality of radiation detection elements arranged in a two-dimensional manner in each region partitioned by the plurality of scanning lines and the plurality of signal lines A detection unit comprising:
When each of the radiation detection elements is arranged and connected, the off-state is applied to the connected scanning line, and the on-state is applied when the on-voltage is applied to the connected scanning line. Then, the switch means for accumulating the charge generated in the radiation detection element in the radiation detection element, and releasing the charge from the radiation detection element to the signal line in the ON state,
A scan driver comprising: a gate driver that switches a voltage applied to the scan line between the on voltage and the off voltage; and a power supply circuit that supplies the on voltage and the off voltage to the gate driver;
A readout circuit that performs an image data readout process of reading out the image data from the radiation detection element by converting the charge emitted from the radiation detection element into the image data;
Informing means for informing completion of a reset process for resetting the radiation detection element;
Control means for controlling at least the scanning drive means, the readout circuit and the notification means;
With
The control means includes
Initiating execution of the reset process for releasing the electric charge from the radiation detection element by resetting the radiation detection element by applying the on-voltage to the scanning line from the scanning drive unit by a predetermined trigger,
When the reset process is completed, the completion of the reset process is notified via the notification means, and the off-voltage is applied to all the scanning lines from the scanning drive means, thereby the charge in the radiation detection element. Transition to charge accumulation mode to accumulate
When transitioning to the charge accumulation mode, the readout circuit periodically performs a readout operation, and repeats leak data readout processing for converting the charge leaked from the radiation detection element via the switch means into leak data. When the value of the leak data decreases and falls below a predetermined threshold, the end of radiation irradiation by the radiation generator is detected,
When the end of irradiation of the radiation is detected, the charge is discharged from the radiation detection element by applying the ON voltage to the scanning line from the scanning drive unit, and the discharged charge is output to the image reading circuit. A radiographic imaging system, wherein the image data reading process is changed to a reading mode for performing the image data reading process by converting the data into data. The radiographic image capturing apparatus includes a communication unit that transmits the image data to the console.
The control means includes
When transitioning to the charge accumulation mode, when the value of the leak data read by the readout circuit increases and exceeds a predetermined threshold, the radiation start by the radiation generator is detected,
Based on the value of the leak data read by the readout circuit, the radiation dose is calculated from the time when the radiation start is detected, and the calculated radiation dose is calculated via the communication means. To notify the console,
The radiographic imaging system according to claim 3, wherein the console includes a display unit capable of displaying an irradiation dose of the radiation notified through the communication unit. The radiographic image capturing apparatus includes:
Subsequent to the radiographic image capturing process, it is configured to perform a dark image acquisition process for acquiring a correction dark image for correcting the radiographic image,
At the time of the dark image acquisition process, the reset process is performed. When the reset process is completed, the charge accumulation mode is entered, the process waits in a state where the radiation is not irradiated, and the transition to the readout mode is performed after a predetermined waiting time has elapsed. And
The control means includes
Calculating the time from the time when the reset process is completed in the radiographic image capturing process to the time when the end of radiation irradiation is detected as an accumulation time, and determining the waiting time based on the calculated accumulation time The radiographic image capturing system according to claim 1, wherein: A plurality of scanning lines and a plurality of signal lines arranged so as to cross each other, and a plurality of radiation detection elements arranged in a two-dimensional manner in each region partitioned by the plurality of scanning lines and the plurality of signal lines A detection unit comprising:
When each of the radiation detection elements is arranged and connected, the off-state is applied to the connected scanning line, and the on-state is applied when the on-voltage is applied to the connected scanning line. Then, the switch means for accumulating the charge generated in the radiation detection element in the radiation detection element, and releasing the charge from the radiation detection element to the signal line in the ON state,
A scan driver comprising: a gate driver that switches a voltage applied to the scan line between the on voltage and the off voltage; and a power supply circuit that supplies the on voltage and the off voltage to the gate driver;
A readout circuit that performs an image data readout process for reading out the image data from the radiation detection element by converting the electric charge emitted from the radiation detection element into image data;
Current detection means for detecting a current flowing through a wiring connecting the power supply circuit and the gate driver, or a current flowing through the scanning line;
Informing means for informing completion of a reset process for resetting the radiation detection element;
Control means for controlling at least the scanning drive means, the readout circuit and the notification means;
With
The control means includes
Initiating execution of the reset process for releasing the electric charge from the radiation detection element by resetting the radiation detection element by applying the on-voltage to the scanning line from the scanning drive unit by a predetermined trigger,
When the reset process is completed, the completion of the reset process is notified via the notification means, and the off-voltage is applied to all the scanning lines from the scanning drive means, thereby the charge in the radiation detection element. Transition to charge accumulation mode to accumulate
When transitioning to the charge accumulation mode, when the value of the current detected by the current detection means decreases and falls below a predetermined threshold, the end of radiation irradiation is detected,
When the end of irradiation of the radiation is detected, the charge is discharged from the radiation detection element by applying the ON voltage to the scanning line from the scanning drive unit, and the discharged charge is output to the image reading circuit. A radiographic imaging apparatus characterized by transitioning to a reading mode in which the image data reading process is performed by converting the data into data. A plurality of scanning lines and a plurality of signal lines arranged so as to cross each other, and a plurality of radiation detection elements arranged in a two-dimensional manner in each region partitioned by the plurality of scanning lines and the plurality of signal lines A detection unit comprising:
When each of the radiation detection elements is arranged and connected, the off-state is applied to the connected scanning line, and the on-state is applied when the on-voltage is applied to the connected scanning line. Then, the switch means for accumulating the charge generated in the radiation detection element in the radiation detection element, and releasing the charge from the radiation detection element to the signal line in the ON state,
A scan driver comprising: a gate driver that switches a voltage applied to the scan line between the on voltage and the off voltage; and a power supply circuit that supplies the on voltage and the off voltage to the gate driver;
A readout circuit that performs an image data readout process for reading out the image data from the radiation detection element by converting the electric charge emitted from the radiation detection element into image data;
Informing means for informing completion of a reset process for resetting the radiation detection element;
Control means for controlling at least the scanning drive means, the readout circuit and the notification means;
With
The control means includes
Initiating execution of the reset process for releasing the electric charge from the radiation detection element by resetting the radiation detection element by applying the on-voltage to the scanning line from the scanning drive unit by a predetermined trigger,
When the reset process is completed, the completion of the reset process is notified via the notification means, and the off-voltage is applied to all the scanning lines from the scanning drive means, thereby the charge in the radiation detection element. Transition to charge accumulation mode to accumulate
When transitioning to the charge accumulation mode, the readout circuit periodically performs a readout operation, and repeats leak data readout processing for converting the charge leaked from the radiation detection element via the switch means into leak data. When the value of the leak data decreases and falls below a predetermined threshold, the end of radiation irradiation is detected,
When the end of irradiation of the radiation is detected, the charge is discharged from the radiation detection element by applying the ON voltage to the scanning line from the scanning drive unit, and the discharged charge is output to the image reading circuit. A radiographic imaging apparatus characterized by transitioning to a reading mode in which the image data reading process is performed by converting the data into data.

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