JP2013195415A - Radiation image imaging device and radiation image imaging system - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a radiation image imaging device that can surely prevent a wrong detection of an irradiation start of radiation due to oscillation and the like added to the device when the irradiation start is detected by the radiation image imaging device body.SOLUTION: In a radiation image imaging device 1, shield means 42 is provided in a predetermined radiation detection element 7A out of each radiation detection element 7 and shields the predetermined radiation detection element 7A such that the predetermined radiation detection element 7A is not irradiated with light or the radiation, and only when a signal dleakA for the predetermined radiation detection element 7A shielded by the shield means 42 is a set threshold value dleakA_th or less and also a signal dleak for a radiation detection element 7 not provided with the shield means 42 is a set threshold value dleak_th or more, control means 22 determines that the irradiation of the radiation is started, and detects the irradiation start.

Description

  The present invention relates to a radiographic image capturing apparatus and a radiographic image capturing system, and more particularly, to a radiographic image capturing apparatus that performs radiographic image capturing by detecting the start of radiation irradiation and a radiographic image capturing system using the same.

  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 A so-called indirect radiographic imaging device that converts the light into a wavelength and then generates electric charges by a photoelectric conversion element such as a photodiode in accordance with the energy of the converted and irradiated light to convert it into an electrical signal (ie, image data). Have been developed. 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 device is known as an FPD (Flat Panel Detector), and is conventionally configured as a so-called special-purpose machine that is integrally formed with a support base (see, for example, Patent Document 1). In recent years, a portable radiographic imaging apparatus in which a radiation detection element or the like is housed in a casing and can be carried has been developed and put into practical use (for example, see Patent Documents 2 and 3).

  In such a radiographic imaging apparatus, for example, as shown in FIG. 3 and the like, which will be described later, normally, a plurality of radiation detection elements 7 are arranged in a two-dimensional form (matrix) on the detection unit P, and each radiation detection element 7 is connected to switch means formed of thin film transistors (hereinafter referred to as TFTs) 8.

  In general, radiographic imaging is performed by irradiating radiation from the radiation source of the radiation generating apparatus to the radiographic imaging apparatus via the subject's body or the like, that is, the subject. Then, after imaging, an ON voltage is sequentially applied from the gate driver 15b to each of the lines L1 to Lx of the scanning line 5 so that each TFT 8 is sequentially turned on, and is generated and accumulated in each radiation detecting element 7 by radiation irradiation. The formed electric charges are sequentially discharged to the signal lines 6 and read out as image data D by the readout circuits 17 respectively.

  By the way, in the conventional radiographic imaging system using such a radiographic imaging apparatus, radiographic imaging was performed by exchanging signals between the radiographic imaging apparatus and the radiation generating apparatus. However, for example, when the manufacturers of the radiographic imaging apparatus and the radiation generation apparatus are different, it may not always be easy to construct an interface between them, or the interface may not be constructed. .

  In such a case, when viewed from the side of the radiographic imaging device, it is not known at what timing the radiation is emitted from the radiation source. Therefore, in such a case, the radiographic imaging device needs to be configured so that the device itself can detect that radiation has been emitted from the radiation source. Various types of radiographic image capturing apparatuses that can detect the start of radiation irradiation and perform image capturing with the radiographic image capturing apparatus itself have been developed.

  For example, in the inventions described in Patent Literature 4 and Patent Literature 5, when radiation is started on the radiation imaging apparatus and charges are generated in each radiation detection element 7, each radiation detection element 7 sends each radiation detection element. The bias line 9 is provided with a current detection means by utilizing the fact that charges flow out to the bias line 9 (see FIG. 3 described later) connected to 7 and the current flowing through the bias line 9 increases. It has been proposed to detect a current value of a current flowing through the inside and detect the start of radiation irradiation based on the current value.

  In addition, as a result of various studies on different methods for detecting that the radiation imaging apparatus itself has irradiated the radiation, the inventors have accurately detected that the radiation imaging apparatus itself has been irradiated. Several techniques that can be performed have been found (see, for example, Patent Documents 6 and 7).

  These new detection methods are configured to detect the start of radiation irradiation based on the data read out by each readout circuit 17 before radiographic image capturing. I will explain later.

  The control unit of the radiographic imaging apparatus is configured to monitor data that changes due to radiation irradiation, such as the current value detected by the current detection unit and the data read by the readout circuit 17 as described above. For example, it is configured to detect that the irradiation of radiation is started when the data becomes equal to or more than a set threshold value.

JP-A-9-73144 JP 2006-058124 A JP-A-6-342099 US Pat. No. 7,211,803 JP 2009-219538 A International Publication No. 2011/13517 Pamphlet International Publication No. 2011-152093 Pamphlet

  By the way, in the research by the present inventors, when an impact, vibration, or the like is applied to the radiographic imaging apparatus configured as described above, the current flowing through the apparatus or the value of read data may become abnormally large. I understand that.

  The cause of such a phenomenon is not necessarily clearly clarified, but the influence of static electricity accumulated on the substrate on which the radiation detection element 7 is formed or the substrate on which the scintillator is formed, or the readout circuit 17. This is considered to be caused by the vibration of a flexible circuit board (also referred to as “Chip On Film” or the like, see FIG.

  Then, as described above, the data that changes when the radiation imaging apparatus is subjected to shock, vibration, or the like and irradiated with radiation, that is, the current value detected by the current detection unit as described above or the readout circuit 17 reads out the data. If the value of the data or the like becomes large, there is a possibility that it is erroneously detected that the irradiation of radiation has been started even though the radiation imaging apparatus is not irradiated with the radiation.

  When such erroneous detection occurs, the radiographic image capturing apparatus automatically shifts to a charge accumulation state to be described later and performs a reading process of the image data D. However, since the radiation image capturing apparatus is not irradiated with radiation, the read image data D is in a state where no subject is captured.

  Therefore, the read image data D is wasted, and in the radiographic imaging apparatus, power is wasted as much as the reading process is wasted. Further, in the radiographic imaging apparatus, it is necessary to newly perform processing such as reset processing of each radiation detection element 7 for the next normal imaging, and an operator such as a radiographer completes these processing. There is a problem that the next shooting cannot be performed immediately.

  The present invention has been made in view of the above points. When the radiation imaging apparatus itself detects the start of radiation irradiation, it erroneously detects the start of radiation irradiation due to the addition of vibration or the like to the apparatus. An object of the present invention is to provide a radiographic imaging apparatus capable of accurately preventing the above.

  In addition, in the radiographic imaging device having the above-described new configuration, a radiation detection element that cannot read the image data D as the main image is generated, and a portion in which no data is read in the image data D Occurs in a linear or dotted manner. That is, line defects and point defects are inevitably generated. Therefore, it is required to accurately correct the image and generate a radiographic image accurately.

  Therefore, the present invention also aims to provide a radiographic imaging system capable of accurately correcting a line defect occurring in the image data D in the radiographic imaging system using the above radiographic imaging apparatus. And

In order to solve the above-described problem, the radiographic imaging device of the present invention includes:
A detection unit comprising a plurality of scanning lines and a plurality of signal lines, and a plurality of radiation detection elements arranged two-dimensionally;
Scanning drive means for switching on and applying an on-voltage and an off-voltage to each scanning line;
Switch means connected to each of the scanning lines and causing the signal lines to discharge charges accumulated in the radiation detection element when an on-voltage is applied;
A readout circuit that converts the electric charge emitted from the radiation detection element into image data and reads the image data;
A detection process for detecting the start of radiation irradiation is performed based on a signal that changes due to the irradiation of radiation, and at least the scanning drive unit and the readout circuit are detected after detection of the start of radiation irradiation. Control means for controlling and reading out the electric charges emitted from the respective radiation detection elements as image data,
With
Among the radiation detection elements, the predetermined radiation detection elements are provided with shielding means for shielding the radiation detection elements from being irradiated with light or radiation,
The control means is configured to set the signal related to the radiation detection element in which the signal related to the predetermined radiation detection element shielded by the shielding means is less than a set threshold and the shield means is not provided. Only when the value is equal to or greater than the threshold value, it is determined that the irradiation is started and the start of irradiation is detected.

Moreover, the radiographic imaging system of the present invention is
The radiographic imaging device of the present invention comprising a communication means;
An image processing device that generates a radiographic image based on the image data transmitted from the radiographic imaging device via the communication unit;
With
In the radiographic imaging apparatus, the image processing apparatus is configured to detect the image data of the predetermined radiation detection element portion shielded by the shielding unit, and each of the radiations adjacent to the predetermined radiation detection element on the detection unit. The image data of the predetermined radiation detection element portion is formed using the image data read from the detection element, and image correction is performed.

  According to the radiographic imaging apparatus of the system as in the present invention, even when a signal that changes due to irradiation with radiation is increased to a threshold value or more with respect to a normal radiation detection element not provided with a shielding unit, the shielding is performed. If the signal related to the predetermined radiation detection element shielded by the means also increases above the threshold value, it is determined that the signal has increased due to the impact or vibration applied to the radiation imaging apparatus, not the radiation irradiation, and the radiation It is determined that the start of irradiation is erroneously detected.

  With this configuration, when the radiation imaging apparatus itself is configured to detect the start of radiation irradiation, it is possible to accurately prevent erroneous detection of the start of radiation irradiation due to the addition of vibration or the like to the apparatus. It becomes possible to do. Therefore, it is possible to accurately avoid the occurrence of problems such as the image data being read based on erroneous detection and power being wasted, and the next shooting cannot be performed immediately.

  In addition, when the signal related to the normal radiation detection element increases to a threshold value or more, if the signal related to the radiation detection element shielded by the shielding means is a small value less than the threshold value, impact or vibration is applied to the radiographic imaging device. Therefore, it can be determined that the radiation image capturing apparatus is irradiated with radiation. Therefore, when radiation is applied to the radiographic imaging device, it is possible to accurately detect the start of radiation irradiation by the radiographic imaging device itself.

  On the other hand, in the radiographic imaging apparatus having the above-described configuration, the image data D as the main image cannot be read by the predetermined radiation detection element, and a line defect or a point defect is inevitably formed in the predetermined radiation detection element portion. Will occur.

However, according to the radiographic imaging system of the system as in the present invention, a line defect or point defect portion is obtained by using the image data D read from a normal radiation detection element other than the predetermined radiation detection element. Thus, it is possible to perform image correction so that image data D is newly formed.
And it becomes possible to generate | occur | produce a radiographic image exactly by performing image correction exactly with respect to the line defect and point defect which arise in the image data D in this way.

It is sectional drawing of a radiographic imaging apparatus. It is a top view which shows the structure of the board | substrate of a radiographic imaging apparatus. It is a block diagram showing the equivalent circuit in the basic composition of a radiographic imaging device. It is a block diagram showing the equivalent circuit about 1 pixel which comprises a detection part. It is a side view explaining the board | substrate with which a flexible circuit board, a PCB board | substrate, etc. were attached. 6 is a timing chart showing charge reset switches, pulse signals, and TFT on / off timings in image data read processing. It is a figure which shows the structural example of the radiographic imaging system which concerns on this embodiment constructed | assembled in the imaging | photography room. It is a figure which shows the structural example of the radiographic imaging system which concerns on this embodiment constructed | assembled on the round-trip vehicle. It is a figure explaining each electric charge leaked from each radiation detection element via TFT in the detection method 1 as leak data. 6 is a timing chart showing on / off timings of charge reset switches and TFTs in a leak data read process. It is a graph showing the example of the time transition of the leak data read. 6 is a timing chart showing charge reset switches, pulse signals, and on / off timings of TFTs in a case where leak data reading processing and radiation detection element reset processing are alternately performed before radiographic imaging. 6 is a timing chart showing the timing of sequentially applying an ON voltage to each scanning line when image data reading processing is repeatedly performed before radiographic image capturing in Detection Method 2; It is a block diagram showing the equivalent circuit in the basic composition of the radiographic imaging device at the time of providing the current detection means in the detection method 3. 6 is a timing chart for explaining the timing of applying an on-voltage to each scanning line in the detection method 1; It is a block diagram showing the equivalent circuit of the radiographic imaging apparatus which concerns on this embodiment provided with the shielding means. It is a figure explaining the reference | standard for determining the non-detection of the radiation irradiation start in the radiographic imaging apparatus which concerns on this embodiment, a detection, and a misdetection. 6 is a timing chart in a configuration example in which an on-voltage is simultaneously applied to all scanning lines to perform reset processing of each radiation detection element. 6 is a timing chart in a configuration example in which a reset process for each radiation detection element is performed by simultaneously applying an on-voltage to some of the plurality of scanning lines. It is a principal part schematic diagram showing the equivalent circuit of the radiographic imaging apparatus which concerns on the modification 1. FIG. It is a principal part schematic diagram showing the equivalent circuit of the radiographic imaging apparatus which concerns on the modification 2. FIG. It is a figure explaining the signal wire wired by the central part of the detection part in modification 4. (A) It is a figure explaining the radiation detection element in which the light from the scintillator in the modification 6 is not irradiated, (B) It is a figure explaining that the light which generate | occur | produced in the fluorescent substance hardly leaks outside. It is a block diagram showing the equivalent circuit of the radiographic imaging apparatus which concerns on the modification 8. It is a figure showing the line defect etc. which generate | occur | produce in image data.

  Embodiments of a radiographic imaging apparatus and a radiographic imaging system according to the present invention will be described below with reference to the drawings.

  In the following description, a so-called indirect radiation image capturing apparatus that includes a scintillator or the like as a radiation image capturing apparatus and converts an irradiated radiation into light of another wavelength such as visible light to obtain an electrical signal will be described. The present invention can also be applied to a so-called direct type radiographic imaging apparatus that directly detects radiation with a radiation detection element without using a scintillator or the like.

  Although the case where the radiographic imaging apparatus is a so-called portable type will be described, the present invention can also be applied to a so-called dedicated machine type radiographic imaging apparatus formed integrally with a support base or the like. Is possible.

[Basic configuration of radiation imaging equipment]
First, a basic configuration of a radiographic image capturing apparatus used in the radiographic image capturing system according to the present embodiment will be described. FIG. 1 is a cross-sectional view of a radiographic image capturing apparatus according to the present embodiment, and FIG. 2 is a plan view illustrating a configuration of a substrate of the radiographic image capturing apparatus.

  In the present embodiment, as shown in FIG. 1, the radiographic image capturing apparatus 1 includes a scintillator 3, a substrate 4, and the like in a housing 2 having a radiation incident surface R that is a surface on which radiation is irradiated. The sensor panel SP is housed. Although not shown in FIG. 1, in this embodiment, the housing 2 is an antenna that is a communication unit that transmits image data D and the like to a console 58 (see FIGS. 7 and 8) described later in a wireless manner. A device 41 (see FIG. 3 described later) is provided.

  Although not shown in FIG. 1, in the present embodiment, the radiographic image capturing apparatus 1 includes a connector on the side surface of the housing 2 or the like, and a console 58 receives signals and data in a wired manner via the connector. Etc. can be sent to. For this reason, this connector also functions as a communication means of the radiation image capturing apparatus 1.

  As shown in FIG. 1, a base 31 is disposed in the housing 2, and the radiation incident surface R side of the base 31 (hereinafter, simply referred to as the upper surface side in accordance with the vertical direction in the drawing). The substrate 4 is provided through a lead thin plate (not shown). A scintillator 3 that converts irradiated radiation into light such as visible light is provided on the scintillator substrate 34 on the upper surface side of the substrate 4, and the scintillator 3 is provided facing the substrate 4 side.

  Further, on the lower surface side of the base 31, a PCB substrate 33 on which electronic components 32 and the like are arranged, a battery 24, and the like are attached. In this way, the sensor panel SP is formed by the base 31, the substrate 4, and the like. In the present embodiment, the buffer material 35 is provided between the sensor panel SP and the side surface of the housing 2.

  In the present embodiment, the substrate 4 is formed of a glass substrate, and as shown in FIG. 2, a plurality of scanning lines 5 and a plurality of signals are provided on the upper surface 4a of the substrate 4 (that is, the surface facing the scintillator 3). The lines 6 are arranged so as to intersect each other. A radiation detection element 7 is provided in each small region r defined by the plurality of scanning lines 5 and the plurality of signal lines 6 on the surface 4 a of the substrate 4.

  In this way, the entire small region r provided with a plurality of radiation detection elements 7 arranged in a two-dimensional form (matrix) in each small region r partitioned by the scanning lines 5 and the signal lines 6, that is, FIG. The area indicated by the alternate long and short dash line in FIG. In the present embodiment, a photodiode is used as the radiation detection element 7, but a phototransistor or the like can also be used, for example.

  Here, the circuit configuration of the radiation image capturing apparatus 1 will be described. FIG. 3 is a block diagram illustrating an equivalent circuit of the radiographic image capturing apparatus 1 according to the present embodiment, and FIG. 4 is a block diagram illustrating an equivalent circuit for one pixel constituting the detection unit P.

  The first electrode 7a of each radiation detection element 7 is connected to a source electrode 8s (see “S” in FIG. 3 and FIG. 4) of a TFT 8 serving as a switch means. Further, the drain electrode 8d and the gate electrode 8g (see “D” and “G” in FIGS. 3 and 4) of the TFT 8 are connected to the signal line 6 and the scanning line 5, respectively.

  The TFT 8 is turned on when a turn-on voltage is applied to the gate electrode 8g via the scanning line 5 from the scanning driving means 15 described later, and is accumulated in the radiation detection element 7 via the source electrode 8s and the drain electrode 8d. The charged electric charge is discharged to the signal line 6. Further, when a turn-off voltage is applied to the gate electrode 8 g via the scanning line 5, the gate electrode 8 g is turned off, the discharge of charge from the radiation detection element 7 to the signal line 6 is stopped, and charge is accumulated in the radiation detection element 7. It is supposed to let you.

  In the present embodiment, as shown in FIGS. 2 and 3, the bias line is applied to the second electrode 7 b of each radiation detection element 7 at a rate of one for each radiation detection element 7 in a row on the substrate 4. 9 is connected, and each bias line 9 is bound to the connection 10 at a position outside the detection portion P of the substrate 4. The connection 10 is connected to a bias power supply 14 (see FIGS. 3 and 4) via an input / output terminal 11 (also referred to as a pad, see FIG. 2). The connection 10 and each bias line 9 are connected from the bias power supply 14 to the connection. Thus, a reverse bias voltage is applied to the second electrode 7b of each radiation detection element 7.

  In the present embodiment, as shown in FIG. 5, chips such as a readout IC 16 (described later) and a gate IC 15d constituting a gate driver 15b of the scanning drive means 15 are incorporated on the film at each input / output terminal 11. The flexible circuit board 12 is connected via an anisotropic conductive adhesive material 13 such as an anisotropic conductive adhesive film (Anisotropic Conductive Film) or an anisotropic conductive paste (Anisotropic Conductive Paste).

  The flexible circuit board 12 is routed to the back surface 4b side of the substrate 4 and is connected to the PCB substrate 33 described above on the back surface 4b side. In this way, the sensor panel SP of the radiation image capturing apparatus 1 is formed. In FIG. 5, illustration of the electronic component 32 and the like is omitted.

  On the other hand, each scanning line 5 is connected to the gate driver 15b of the scanning driving means 15 via the input / output terminal 11, respectively. In the scanning drive means 15, an ON voltage and an OFF voltage are supplied from the power supply circuit 15a to the gate driver 15b via the wiring 15c, and applied to the lines L1 to Lx of the scanning line 5 by the gate driver 15b. The voltage is switched between an on voltage and an off voltage.

  Each signal line 6 is connected to each readout circuit 17 built in the readout IC 16 via each input / output terminal 11. In the present embodiment, the readout circuit 17 is mainly composed of 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 read IC 16. 3 and 4, the correlated double sampling circuit 19 is represented as CDS.

  In the present embodiment, the amplifier circuit 18 is a charge amplifier circuit including an operational amplifier 18a, a capacitor 18b and a charge reset switch 18c connected in parallel to the operational amplifier 18a, and a power supply unit 18d that supplies power to the operational amplifier 18a and the like. It consists of The signal line 6 is connected to the inverting input terminal on the input side of the operational amplifier 18a of the amplifier circuit 18.

  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. In this embodiment, a switch 18e that opens and closes in conjunction with the charge reset switch 18c is provided between the operational amplifier 18a and the correlated double sampling circuit 19, and the switch 18e is the charge reset switch 18c. Is turned off / on in conjunction with the on / off action.

  In the process of reading the image data D from each radiation detection element 7, as shown in FIG. 6, the TFT 8 of each radiation detection element 7 is in a state where the charge reset switch 18c of the amplifier circuit 18 is turned off. When the ON voltage is applied to the signal line 6, electric charges are discharged from the radiation detection elements 7 to the signal lines 6, and flow into the capacitors 18 b of the amplification circuits 18 of the readout circuits 17 to be 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.

  The correlated double sampling circuit 19 outputs an increase in the output value from the amplifier circuit 18 before and after the charge flows from each radiation detection element 7 as analog value image data D to the downstream side. The output image data D is sequentially transmitted to the A / D converter 20 via the analog multiplexer 21, and is sequentially converted into digital image data D by the A / D converter 20 and stored in the storage means 23. Output and save sequentially. In this way, the reading process of the image data D 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, etc., not shown, connected to a bus, an FPGA (Field Programmable Gate Array), or the like. It is configured. It may be configured by a dedicated control circuit.

  Then, the control unit 22 controls the operation of each functional unit of the radiographic imaging apparatus 1 such as controlling the scanning driving unit 15 and the readout circuit 17 to perform the readout process of the image data D as described above. It has become. As shown in FIGS. 3 and 4, the control means 22 is connected to a storage means 23 composed of SRAM (Static RAM), SDRAM (Synchronous DRAM) or the like.

  In the present embodiment, the control unit 22 is connected to the antenna device 41 described above, and is further necessary for each functional unit such as the scanning drive unit 15, the readout circuit 17, the storage unit 23, and the bias power source 14. A battery 24 for supplying power is connected.

  Note that the configuration, control, and the like for the radiation irradiation start detection process in the radiographic image capturing apparatus 1 will be described after the configuration of the radiographic image capturing system 50 according to the present embodiment is described.

[Radiation imaging system]
Next, the configuration and the like of the radiation image capturing system 50 according to the present embodiment will be described. FIG. 7 is a diagram illustrating a configuration example of the radiation image capturing system 50 according to the present embodiment. In FIG. 7, the case where the radiographic imaging system 50 is constructed in the imaging room R1 is shown.

  A bucky device 51 is installed in the photographing room R1, and the bucky device 51 can be used by loading the radiographic image photographing device 1 in the cassette holding portion 51a. FIG. 7 shows the case where a bucky device 51A for standing position shooting and a bucky device 51B for standing position shooting are installed as the bucky device 51. For example, only one of the bucky devices 51 is provided. It may be done.

  As shown in FIG. 7, the imaging room R1 is provided with at least one radiation source 52A for irradiating the radiation image capturing apparatus 1 loaded in the Bucky apparatus 51 via a subject. In the present embodiment, by moving the radiation source 52A or changing the irradiation direction of radiation, it is possible to irradiate both the standing-up imaging device 51A and the lying-up imaging device 51B. It is like that.

  The imaging room R1 is provided with a repeater (also referred to as a base station or the like) 54 for relaying communication between the devices in the imaging room R1 and the devices outside the imaging room R1. In the present embodiment, the repeater 54 is provided with an access point 53 so that the radiographic imaging apparatus 1 can transmit and receive image data D, signals, and the like in a wireless manner.

  The repeater 54 is connected to the radiation generator 55 and the console 58, and LAN (Local Area Network) communication is transmitted to the repeater 54 from the radiation imaging apparatus 1, the console 58, and the like to the radiation generator 55. A converter (not shown) that converts a signal for use into a signal for use in the radiation generator 55 and the reverse conversion is incorporated.

  In the present embodiment, the front room (also referred to as an operation room) R2 is provided with an operation console 57 of the radiation generating device 55. The operation panel 57 is operated by an operator such as a radiation engineer. An exposure switch 56 is provided for instructing the generator 55 to start radiation irradiation. The radiation generating device 55 is configured to emit radiation from the radiation source 52 when the exposure switch 56 is operated by the operator. Further, various controls such as adjusting the radiation source 52 so as to emit an appropriate dose of radiation are performed.

  As shown in FIG. 7, in the present embodiment, a console 58 constituted by a computer or the like is provided in the front chamber R2. The console 58 can be configured to be provided outside the imaging room R1 and the front room R2, in a separate room, and the like, and is installed in an appropriate place.

  Further, the console 58 is provided with a display unit 58a configured to include a CRT (Cathode Ray Tube), an LCD (Liquid Crystal Display), and the like, and also includes input means such as a mouse and a keyboard (not shown). Yes. In addition, the console 58 is connected to or has a built-in storage means 59 composed of an HDD (Hard Disk Drive) or the like.

  On the other hand, as shown in FIG. 8, the radiographic imaging device 1 is not loaded in the bucky device 51 and can be used in a so-called state. For example, when the patient H cannot get up from the bed B of the patient room R3 and cannot go to the imaging room R1, the radiographic imaging device 1 is brought into the patient room R3 as shown in FIG. It can be used by being inserted into the patient's body or applied to the patient's body.

  In this case, as shown in FIG. 8, a so-called portable radiation generating device 55 is brought into the hospital room R <b> 3, for example, by being mounted on a roundabout wheel 71. The radiation 52P of the portable radiation generating device 55 is configured so as to be able to irradiate radiation in an arbitrary direction. For the radiation imaging apparatus 1 inserted between the bed B and the patient's body, etc. It is possible to irradiate radiation from an appropriate distance and direction.

  Further, in this case, a repeater 54 provided with an access point 53 is built in the radiation generator 55, and the repeater 54 communicates between the radiation generator 55 and the console 58 in the same manner as described above. The communication between the radiation image capturing apparatus 1 and the console 58, the transmission of image data D, and the like are relayed.

  In addition, as shown in FIG. 7, the radiographic imaging device 1 is composed of the body of a patient (not shown) lying on the bucky device 51B for supine photography in the photographing room R1 and the bucky device 51B for supine photography. It can also be used by being inserted between them or being applied to the patient's body on the bucky device 51B for lying position photography. In this case, the portable radiation 52P or the radiation source 52A installed in the photographing room R1 Either of these can be used.

  In the present embodiment, the console 58 also functions as an image processing device. When image data D or the like is transmitted from the radiographic image capturing device 1, offset correction, gain correction, and defective pixels are based on the data. A radiographic image is generated by performing precise image processing such as correction and gradation processing according to the imaging region.

[How to detect the start of radiation irradiation]
Next, a basic configuration of the radiation irradiation start detection method used in the radiographic imaging apparatus 1 according to the present embodiment will be described.

  In the present embodiment, as described above, an interface is not constructed between the radiation image capturing apparatus 1 and the radiation generating apparatus 55 (see FIGS. 7 and 8), and the radiation image capturing apparatus 1 itself uses the radiation of the radiation generating apparatus. It is comprised so that it may detect that the radiation was irradiated from the source. As a method for detecting the start of radiation irradiation, for example, the detection methods described in Patent Document 6 and Patent Document 7 described above can be employed. Hereinafter, these detection methods will be described.

[Detection method 1]
The detection method 1 is a detection method described in Patent Document 6 described above. For details of this detection method 1, refer to this document.

  In this detection method 1, the control means 22 of the radiographic image capturing apparatus 1 is configured to repeatedly read out the leak data dleak before radiographic image capturing. As shown in FIG. 9, the leak data dleak is a signal line of charge q leaked from each radiation detection element 7 through each TFT 8 which is in an off state in a state where an off voltage is applied to each scanning line 5. Data corresponding to a total value of every six.

  Then, in the readout process of the leak data dleak, as shown in FIG. 10, each readout circuit is supplied from the control means 22 in a state in which each TFT 8 is turned off by applying an off voltage to each line L1 to Lx of the scanning line 5. The pulse data Sp1 and Sp2 are transmitted to 17 correlated double sampling circuits 19 (see CDS in FIGS. 3 and 4), and the leak data dleak is read out.

  In this case, unlike the case of the reading process of the image data D (see FIG. 6), the ON voltage is not applied to each scanning line 5 from the gate driver 15b. Each radiation detection is performed through each TFT 8 accumulated in the capacitor 18b of the amplifier circuit 18 from the time when the pulse signal Sp1 is transmitted from the control means 22 to the correlated double sampling circuit 19 until the pulse signal Sp2 is transmitted. The total value of the charge q leaked from the element 7 for each signal line 6 is read as leak data dleak.

  When the leak data dleak is configured to be read out in this way, when radiation irradiation to the radiation image capturing apparatus 1 is started, light converted from the radiation by the scintillator 3 (see FIG. 1) is irradiated to each TFT 8. Is done. As a result, the inventors have found that the charges q (see FIG. 9) leaking from the radiation detection elements 7 via the TFTs 8 are increased.

  Therefore, when the radiation image capturing apparatus 1 is irradiated with radiation, the charge q leaked from each radiation detection element 7 through each TFT 8 increases, so that the value of the leaked data dleak to be read is as shown in FIG. The value of leak data dleak read before that becomes larger (see time t1 in FIG. 11). As described above, in the detection method 1, the value of the leak data dleak to be read is changed by the irradiation of radiation.

  Therefore, by using this, for example, as shown in FIG. 11, a threshold value dleak_th is set for the leak data dleak, and when the read leak data dleak becomes equal to or higher than the threshold value dleak_th, radiographic imaging is performed. The apparatus 1 can be configured to detect the start of radiation irradiation.

  In this detection method 1, the leak data dleak is read out in a state where each TFT 8 is turned off as described above. If each TFT 8 is left in this OFF state, dark charges (also referred to as dark current or the like) generated in each radiation detection element 7 are continuously accumulated in each radiation detection element 7.

  Therefore, when the detection method 1 is employed, the radiation detection element 7 is usually reset between the leak data dleak read process and the next leak data dleak read process. That is, as shown in FIG. 12, the detection method 1 is normally configured such that the reading process of the leak data dleak and the reset process of each radiation detection element 7 are alternately performed.

[Detection method 2]
The detection method 2 is a detection method described in Patent Document 7 described above. For details of this detection method 2, refer to the same document.

  In this detection method 2, the control means 22 of the radiographic image capturing apparatus 1 controls each readout circuit 17 and the like in the same manner as the readout process of the image data D shown in FIG. As shown in FIG. 4, the on-voltage is sequentially applied from the gate driver 15b of the scanning drive means 15 to each of the lines L1 to Lx of the scanning line 5, and the above-described image data for detecting the start of irradiation (hereinafter referred to as “image data”). In order to distinguish from the image data D as the main image, this is indicated as image data d for irradiation start detection)).

  When the radiation image capturing apparatus 1 is irradiated with radiation, a charge is newly generated in each radiation detection element 7, and therefore, as in the case of the leak data dleak shown in FIG. The value of the image data d is larger than the value of the image data d for irradiation start detection that has been read before. Thus, in the detection method 2, the value of the image data d for irradiation start detection to be read is changed by irradiation with radiation.

  Therefore, although not shown in the drawing, a threshold value dth is set for the image data d for irradiation start detection using this, and the read image data d for detection of irradiation start is greater than or equal to the threshold value dth. At this point, the radiation image capturing apparatus 1 can be configured to detect the start of radiation irradiation.

[Detection method 3]
In addition to the detection methods 1 and 2 described above, for example, as described in Patent Document 4 and Patent Document 5 described above, for example, radiation irradiation to the radiation image capturing apparatus 1 is started and each radiation is started. When charges are generated in the detection elements 7 (see FIG. 3 and the like), the charges flow out from the radiation detection elements 7 to the bias lines 9 connected to the radiation detection elements 7 and the current flowing through the bias lines 9 increases. It is also possible to make use of this to detect the start of radiation irradiation. For details of the detection method 3, refer to the above-mentioned documents.

  Specifically, as shown in FIG. 14, for example, a current detection unit 26 is provided on the bias line 9 or its connection 10, and the current detection unit 26 detects the value of the current flowing in the bias line 9 or the connection 10. It is configured to output to the control means 22.

  In such a configuration, when radiation is applied to the radiation imaging apparatus 1, the value of the current flowing through the bias line 9 and the connection 10 as described above is greater than the value of the current detected before that. Also grows. As described above, in the detection method 3, the value of the current flowing through the bias line 9 and the connection 10 changes due to the irradiation of radiation.

  Therefore, using this, although not shown in the figure, a threshold is set for the current flowing through the bias line 9 and the connection 10, that is, the current value detected by the current detection means 26, and the detected current It can be configured to detect the start of radiation irradiation on the radiographic imaging apparatus 1 when the value of becomes equal to or greater than the threshold.

  As described above, in the radiographic image capturing apparatus 1, for example, the above-described detection methods 1 to 3 are used to detect that the radiation image capturing apparatus 1 itself detects that radiation has been emitted from the radiation source of the radiation generating apparatus. It becomes possible to comprise.

  In addition, as described in Patent Documents 5 to 7, the detection methods 1 to 3 and the like are further improved, and the radiation imaging apparatus 1 itself accurately detects that radiation irradiation has started. It is also possible to configure as described above.

[Each process after detection of radiation irradiation start]
Before explaining the configuration peculiar to the present invention and the like for accurately preventing erroneous detection of the start of radiation irradiation due to the addition of vibration or the like to the radiographic imaging apparatus 1, Each process after the image capturing apparatus 1 detects that radiation irradiation has been started as described above will be described.

  When the control means 22 of the radiographic image capturing apparatus 1 detects that radiation irradiation has been started as described above, for example, as shown in FIG. 5 so that the off voltage is applied to all the lines L1 to Lx, the TFTs 8 are turned off, and the charges generated in the radiation detection elements 7 due to radiation irradiation are accumulated in the radiation detection elements 7. Shift to the charge accumulation state.

  In FIG. 15, “R” represents that the reset process of each radiation detection element 7 is performed, and “L” represents that the read process of the leak data dleak is performed. Further, Tac in the figure will be described later.

  For example, after the start of radiation irradiation is detected and the charge accumulation state is continued for a predetermined time, the control unit 22 performs a process of reading the image data D as the main image.

  At this time, in the present embodiment, as shown in FIG. 15, the control means 22 scans the scanning line 5 to which the ON voltage is applied at the time of detecting the start of radiation irradiation or just before that (scanning line 5 in the case of FIG. 15). Application of the on-voltage is started from the scanning line 5 to which the on-voltage is to be applied next (line L5 of the scanning line 5 in the case of FIG. 15), and the on-voltage is applied to each scanning line 5 from the gate driver 15b. The image data D is read out by being sequentially applied.

  On the other hand, when the control unit 22 of the radiographic image capturing apparatus 1 completes the reading process of the image data D as the main image as described above, it subsequently performs the reading process of the offset data O. Note that the offset data O can be read out before radiographic image capturing.

  In the present embodiment, although not shown, the control means 22 performs the same processing sequence as the processing sequence until the reading processing of the image data D as the main image shown in FIG. The offset data O is read repeatedly.

  That is, after completion of the reading process of the image data D, in the case of the detection method 1, the reading process of the leak data dleak and the reset process of each radiation detection element 7, and in the case of the detection method 2, the image data d for irradiation start detection. Is read out a predetermined number of times, then the state is shifted to the charge accumulation state, and thereafter the offset data O is read out.

  And the control means 22 of the radiographic imaging device 1 will complete | finish the read-out process of offset data O, image for each radiation detection element 7 with respect to image processing apparatuses, such as a console 58 (refer FIG.7 and FIG.8). Data D and offset data O are transmitted. The radiographic image capturing apparatus 1 can also be configured to transmit preview image data to the console 58 or the like at an appropriate timing.

[Configuration etc. to prevent erroneous detection of radiation start due to vibrations, etc.]
Next, in the radiographic image capturing apparatus 1 according to the present exemplary embodiment, it is possible to accurately prevent erroneous detection of radiation irradiation start due to the addition of vibration or the like to the apparatus. The configuration and the like will be described. The operation of the radiographic image capturing apparatus 1 and the radiographic image capturing system 50 according to the present embodiment will also be described.

  In the present invention, in addition to the basic configuration of the radiographic image capturing apparatus 1 as described above, a predetermined radiation detection element 7 (hereinafter, referred to as the radiation detection element 7) among the radiation detection elements 7 (see FIGS. 2 and 3) of the detection unit P. The radiation detection element 7A is distinguished from other radiation detection elements 7). When the radiation imaging apparatus 1 is an indirect type, the radiation detection element 7A is not irradiated with light from the scintillator 3. Shielding means is provided that shields or shields the radiation detecting element 7A from being irradiated with radiation when the radiation image capturing apparatus 1 is a direct type.

  And the control means 22 is the data (namely, leak data dleak (detection method 1), the image data d for detection of irradiation start (detection method 2), the electric current which flows through the connection 10, etc. regarding the radiation detection element 7A provided with the shielding means. (Detection method 3)) is less than a set threshold value, and radiation irradiation starts only when the data relating to the radiation detection element 7 not provided with the shielding means is equal to or greater than the set threshold value. It is determined that the irradiation has started, and the start of irradiation is detected.

  This will be specifically described below. In the following, a so-called indirect radiation image capturing apparatus including the scintillator 3 (see FIG. 1) as described above will be described as the radiation image capturing apparatus 1, but the present invention does not involve the scintillator 3 or the like. In addition, the present invention can be applied to a so-called direct type radiographic imaging apparatus in which radiation is directly detected by a radiation detection element.

  In the present embodiment, for example, as shown in FIG. 16, all of the radiation detection elements connected to a predetermined signal line 6 </ b> A or a predetermined signal line 6 </ b> A among the radiation detection elements 7 provided in the detection unit P. The element 7A is provided with a shielding means 42 for shielding the light from the scintillator 3 (not shown in FIG. 16) from being applied to the radiation detection element 7A. That is, the shielding means 42 is provided between the radiation detection element 7 </ b> A and the scintillator 3.

  In the case of the indirect radiographic imaging apparatus 1 as in the present embodiment, the shielding means 42 may be any means as long as it shields the light emitted from the scintillator 3. For example, the shielding means 42 is a metal plate such as an aluminum plate. Alternatively, it can be made of an inorganic material such as carbon or an organic material such as resin. Further, in the case of a direct type radiographic imaging apparatus in which radiation is directly applied to the radiation detection element 7, the shielding means 42 can be composed of a lead plate or the like that shields radiation.

  In particular, when the detection method 1 is used to detect the start of radiation irradiation, each TFT 8A, which is a switch means of each radiation detection element 7A, is prevented from being irradiated with light or radiation. Therefore, the shielding means 42 needs to be configured to shield not only the radiation detection element 7A but also at least each TFT 8A as shown in FIG.

  In the following description, a case where the above detection method 1 is employed as a method for detecting the start of radiation irradiation, that is, a case where leak data dleak (see FIG. 9) is used as data that changes due to radiation irradiation will be described. However, the same description can be made when the image data d for detection of irradiation start (detection method 2), the value of the current flowing through the connection 10 or the like (detection method 3) is used.

  Furthermore, in the following, the leakage data dleak or the like corresponding to the total value of the charge q leaked through the TFT 8A of the radiation detection element 7A provided with the shielding means 42 for each signal line 6A is not shielded by the shielding means 42. In order to distinguish from normal leak data dleak from the radiation detection element 7 (hereinafter referred to as normal radiation detection element 7), it is referred to as leak data dleak A or the like.

  And the control means 22 not only monitors the normal leak data dleak read out via the TFT 8 of the normal radiation detection element 7 as in the above basic configuration, but also the radiation shielded by the shielding means 42. The leak data dleakA read through the TFT 8A of the detection element 7A is also monitored.

  In the present embodiment, the control means 22 determines non-detection, detection, and erroneous detection of the start of radiation irradiation in accordance with the reference shown in FIG.

  That is, the control means 22 has the radiation detection element 7A shielded by the shielding means 42 when the normal leak data dleak read out via the TFT 8 of the normal radiation detection element 7 is less than the threshold dleak_th (see FIG. 11). When the leak data dleakA read out through the TFT 8A is also less than the threshold dleakA_th, it is determined that the radiation image capturing apparatus 1 has not yet been irradiated with radiation (see reference A (not detected) in FIG. 17).

  In addition, when the radiation image capturing apparatus 1 is irradiated with radiation, the control means 22 increases the leak data dleak because the light from the scintillator 3 reaches the TFT 8 portion of the normal radiation detection element 7. As a result, the threshold value is greater than or equal to the threshold value dleak_th. However, in the TFT 8A portion of the radiation detection element 7A shielded by the shielding means 42, the light from the scintillator 3 is shielded by the shielding means 42, so that the leak data dleak does not increase and remains below the threshold dleak_th.

  Therefore, when the leak data dleak is equal to or greater than the threshold value dleak_th, but when the leak data dleakA is less than the threshold value dleak_th, the control unit 22 determines that the radiation imaging apparatus 1 has started irradiation and starts irradiation. Detect (see reference B (detection) in FIG. 17).

  On the other hand, when the leak data dleakA that should not increase because light or radiation is shielded by the shielding means 42 increases, it is not because the radiation image capturing apparatus 1 is irradiated with radiation, but to the radiation image capturing apparatus 1. This is thought to be due to the impact or vibration. At the same time, even if the normal leak data dleak read out through the TFT 8 of the normal radiation detection element 7 is equal to or greater than the threshold value dleak_th, it is not because the radiation image capturing apparatus 1 is irradiated with radiation, This is considered to be because an impact, vibration, or the like was applied to the radiation image capturing apparatus 1.

  Therefore, the control unit 22 detects the radiation shielded by the shielding unit 42 in such a case, that is, even when the normal leak data dleak read out through the TFT 8 of the normal radiation detection element 7 is equal to or greater than the threshold dleak_th. If the leak data dleakA read out through the TFT 8A of the element 7A is also equal to or greater than the threshold value dleakA_th, it is determined that the radiation start has been erroneously detected (see reference C (false detection) in FIG. 17). ).

  When the control means 22 determines that the start of radiation irradiation has been erroneously detected, the control means 22 does not shift to the charge accumulation state, the image data D read processing, etc., as shown in FIG. 15, and the leak data dleak, dleak A read processing The state in which the reset processing of the radiation detection elements 7 and 7A is alternately repeated is maintained. That is, it returns to the state of the detection process of the start of radiation irradiation.

  As described above, according to the radiographic imaging device 1 according to the present embodiment, among the radiation detection elements 7 on the detection unit P, the predetermined radiation detection element 7A has the light detected by the radiation detection element 7A and the TFT 8A. A shielding means 42 is provided to shield the radiation from being irradiated.

  When the signal related to the normal radiation detection element 7 not provided with the shielding means 42 (ie, leak data dleak read through the TFT 8 of the normal radiation detection element 7) increases to a threshold value (for example, the threshold value dleak_th) or more. However, if the signal related to the predetermined radiation detection element 7A shielded by the shielding means 42 also increases beyond the threshold value, it is because the impact or vibration is applied to the radiation image capturing apparatus 1 instead of radiation irradiation. It is determined that the signal (for example, leak data dleak) has increased, and it is determined that the start of radiation irradiation has been erroneously detected.

  With this configuration, for example, when the radiation imaging apparatus 1 itself is configured to detect the start of radiation irradiation using the detection method 1 described above, the irradiation of radiation is caused by the addition of vibration or the like to the apparatus. It is possible to accurately prevent erroneous detection of the start.

  In spite of erroneous detection, the image data D is read out by shifting to the charge accumulation state, and the read image data D is wasteful because the subject is not photographed. It is possible to accurately avoid the occurrence of problems such as wasteful power consumption due to the reading process and the inability to immediately perform the next shooting.

  Further, when the signal related to the normal radiation detection element 7 increases to a threshold value or more, if the signal related to the radiation detection element 7A shielded by the shielding means 42 is a small value that is less than the threshold value, the radiation image capturing apparatus 1 is shocked. It can be determined that the radiation image capturing apparatus 1 is not irradiated with vibration or the like but is irradiated with radiation.

  Therefore, in such a case, by determining that radiation irradiation has started, when the radiation imaging apparatus 1 is irradiated with radiation, for example, a radiation image using the detection method 1 described above is used. It is possible to accurately detect the start of radiation irradiation by the imaging apparatus 1 itself.

  Note that the threshold value dleak_th for leak data dleak read out via the TFT 8 of the normal radiation detection element 7 and the threshold value dleakA_th for leak data dleakA read out via the TFT 8A of the radiation detection element 7A shielded by the shielding means 42 are the same. It may be set to a value, or may be set to different values.

  Further, when the above-described detection method 1 is employed as a method for detecting the start of radiation irradiation, in FIG. 12 and FIG. 15, the reset process of each radiation detection element 7 that is alternately performed with the reading process of the leak data dleak The case where the ON voltage is sequentially applied from the 15 gate drivers 15b to the lines L1 to Lx of the scanning line 5 is shown.

  However, this is the same in the case of the detection method 3 described above, but it is not always necessary to make such a configuration. For example, as shown in FIG. 18, the on-voltage is applied to all the lines L1 to Lx of the scanning line 5 from the gate driver 15b. It is also possible to perform a reset process of each radiation detection element 7 by simultaneously applying.

  For example, as shown in FIG. 19, an on-voltage is simultaneously applied from the gate driver 15b of the scanning drive means 15 to a plurality of scanning lines 5 among all the scanning lines 5 connected to the gate driver 15b. It is also possible to configure so that each radiation detection element 7 is reset. At that time, for example, as shown in FIG. 19, the gate driver 15b applies an ON voltage to the lines L1 to Lm of the scanning line 5 and turns on the lines Lm + 1 to Lx of the scanning line 5. It is also possible to configure such that voltage application is repeated alternately.

  When configured as shown in FIGS. 18 and 19, the period in which the TFTs 8 and 8A are turned off is shorter than in the case shown in FIGS. 12 and 15, and the radiation detection elements 7 and 7A have a shorter period. It becomes possible to further reduce the amount of accumulated dark charge.

[Modification]
Various modifications can be made to the radiation image capturing apparatus 1 according to the present embodiment. Hereinafter, modified examples will be described.

[Modification 1]
In the above embodiment, as shown in FIG. 16, a configuration is adopted in which all the radiation detection elements 7 </ b> A and TFTs 8 </ b> A connected to one or a predetermined plurality of signal lines 6 </ b> A are shielded by the shielding means 42. Indicated. However, instead of such a configuration, for example, as shown in FIG. 20, only a part of the plurality of radiation detection elements 7A among the radiation detection elements 7 connected to the signal line 6A is shielded by the shielding means 42. The other radiation detection elements 7 can be configured not to be shielded by the shielding means 42.

[Modification 2]
In addition, as shown in FIG. 21, it is also possible to provide the shielding means 42 so as to be scattered so that the radiation detection elements 7A shielded by the shielding means 42 are scattered on the signal line 6A.

  In the case of the first and second modifications, some of the radiation detection elements 7A connected to the signal line 6A are shielded by the shielding means 42, while the other radiation detection elements 7 are shielded. Not. Therefore, when the radiation imaging apparatus 1 is irradiated with radiation, since the light from the scintillator 3 does not reach the TFT 8A of each radiation detection element 7A, the leaked charge q (see FIG. 9) does not increase, but the signal line 6A Since the light from the scintillator 3 reaches the TFTs 8 of the other radiation detection elements 7 connected to, the leaked charge q increases.

  Therefore, as in the above-described embodiment, when the TFTs 8A of all the radiation detection elements 7A connected to the signal line 6A are shielded, the readout circuit 17A can be used even if the radiation imaging apparatus 1 is irradiated with radiation. The leak data dleak read out by the read circuit 17A does not increase, but in the case shown in FIG. 20 or FIG. 21, the leak data dleakA read out by the read circuit 17A increases by the amount of the radiation detection element 7 not provided with the shielding means 42. It becomes a state to do.

  However, the degree of increase in the leak data dleakA read by the read circuit 17A is such that the shield means 42 is not provided and the normal signal line 6 through which the light from the scintillator 3 reaches all the TFTs 8 is connected. The degree of increase of the leak data dleak read at 17 is smaller.

  Further, when vibration or the like is applied to the radiation image capturing apparatus 1, the leak data dleak read by the read circuit 17 and the leak data dleak read by the read circuit 17A are the same regardless of the presence or absence of the shielding means 42. Greatly increases.

  Therefore, by setting the threshold value dleakA_th (see FIG. 17) relating to the leak data dleakA to an appropriate value, when the radiation image capturing apparatus 1 is irradiated with radiation (that is, in the case of the reference B in FIG. 17), the radiation image capturing is performed. It is possible to accurately separate the case where vibration or the like is applied to the device 1 (that is, the case of the reference C in FIG. 17).

  In addition, it is possible to accurately detect the start of radiation irradiation on the radiographic imaging apparatus 1 and to accurately prevent erroneous detection when vibration or the like is applied to the radiographic imaging apparatus 1.

[Modification 3]
In addition, in the present embodiment and the first and second modifications described above, at least when radiation is applied to the radiographic imaging device 1 via the signal line 6A, regardless of whether vibration or the like is applied to the radiographic imaging device 1. Thus, the charge flowing into the readout circuit 17A is smaller than the charge flowing into the readout circuit 17 via the normal signal line 6 in which the shielding means 42 is not provided.

  Therefore, for example, the capacitance cf of the capacitor 18b (see FIG. 4) of the amplifier circuit 18 of the readout circuit 17A is used as the capacitance of the amplifier circuit 18 of the readout circuit 17 to which the normal signal line 6 not provided with the shielding means 42 is connected. It is possible to set the capacitance smaller than the normal capacitance cf of the capacitor 18b.

  With this configuration, it is possible to read out the data by increasing and amplifying the increase / decrease in the charge that flows into only a small amount, and more accurately determining whether or not the leak data dleakA or the like has become equal to or greater than the threshold dleakA_th. It becomes possible.

  In this case, the capacitance cf of the capacitor 18b of each readout circuit 17A cannot be set individually, and may be set only for each readout IC 16.

  Therefore, in such a case, the shielding means 42 is more effective than the readout IC 16 having only the readout circuit 17 connected to the signal line 6 to which the radiation detection element 7 not provided with the shielding means 42 is connected. The amplifying circuit 18 of each readout circuit 17A has a small capacitance cf in the readout IC 16 incorporating the readout circuit 17A connected to the signal line 6A to which the predetermined radiation detection element 7A shielded by The capacitance cf of the capacitor 18b is set to be variable.

  For the readout IC 16 that is set so that the capacitance cf of each built-in capacitor 18b is small, the capacitance cf of each capacitor 18b is restored to the original value when the image data D as the main image is read out. Configured to return to capacity. This is because the correct value of the image data D is read out.

[Modification 4]
In addition, in this embodiment and said modification 1-3, the shielding means 42 was wired by the center part of the detection part P among each signal line 6 on the detection part P, for example, as shown in FIG. A predetermined radiation detecting element 7A or TFT 8A connected to the signal line 6A can be shielded by the shielding means 42.

  In normal radiographic imaging, the radiation field is often set to a range including the central portion of the radiation incident surface R (see FIG. 1) of the radiographic imaging device 1. For this reason, if configured as described above, there is a high possibility that radiation or light from the scintillator 3 is irradiated to the signal line 6 </ b> A during radiographic imaging.

  However, since the shielding means 42 accurately shields the radiation detection element 7A and the TFT 8A from being irradiated with radiation or light, whether or not radiation irradiation has been started by using the reference shown in FIG. ) Or whether or not the start of radiation irradiation has been erroneously detected (reference C).

[Modification 5]
By the way, in the central part of the radiographic image, there are many cases where an important part such as a lesion part of a patient as a subject is captured. Therefore, if the predetermined radiation detection element 7A and TFT 8A connected to the signal line 6A wired in the center of the detection part P as described above are shielded by the shielding means 42, a lesioned part or the like is photographed. There is a high possibility that a line defect, which will be described later, is generated in the portion.

  As will be described later, the line defect is configured so that the line defect does not occur as much as possible in the image area in which an important part such as a lesion is photographed even though the image is appropriately corrected in later image processing. It is preferable to do.

  Therefore, although not shown, the shielding means 42 is connected to, for example, a signal line 6A wired at the end of the detection unit P (in FIG. 22, a signal line wired at the left end or the right end of the detection unit P). The predetermined radiation detection element 7A and TFT 8A can be configured to be shielded by the shielding means 42.

  If configured in this way, as described above, avoiding a central portion where an important portion such as a lesion is likely to be imaged, and avoiding an end portion of a radiographic image where an important portion is not likely to be imaged. It is possible to configure so that a line defect occurs in the portion.

  At that time, in order to be able to accurately determine the detection of radiation irradiation start or erroneous detection using the above-mentioned criteria, the detection unit P provided with the shielding means 42 is used at the time of radiographic image capturing. It is preferable to set the irradiation field so that the radiation is also applied to the signal line 6A at the end of the image.

[Modification 6]
On the other hand, in the present embodiment and each of the above-described modifications 1 to 5, the shielding means 42 for shielding each radiation detection element 7A and the TFT 8A is provided, and the light emitted from the scintillator 3 is shielded by the shielding means 42. Explained the case.

  However, in the indirect radiation imaging apparatus 1, for example, as shown in FIG. 23A, a radiation detection element 7B that is not irradiated with light from the scintillator 3 may be provided at the end of the detection unit P. .

  As shown in FIG. 23 (B), when the scintillator 3 is formed of a columnar crystal phosphor 3a, the light generated in the phosphor 3a upon irradiation with radiation passes through the inside of the phosphor 3a. At this time, since light is efficiently reflected by the inner wall 3b of the columnar phosphor 3a, almost no light leaks out of the phosphor 3a.

  For this reason, the light generated in the phosphor 3a propagates efficiently inside the phosphor 3a, and is characterized in that the radiation detection element 7 is irradiated with high efficiency from the tip of the phosphor 3a. As can be seen from this feature, light from the scintillator 3 is hardly irradiated to the radiation detection element 7B provided at the end of the detection unit P shown in FIG. .

  That is, the radiation detection element 7B and its TFT 8B (not shown in FIG. 23A) are shielded by the shielding means 42 in this embodiment and the above-described modifications 1 to 5 without being shielded by the shielding means 42. It functions in the same manner as the radiation detecting element 7A and TFT 8A.

  Therefore, in such a radiographic imaging apparatus 1, instead of providing the shielding means 42 as in the present embodiment and the above-described first to fifth modifications, the control means 22 emits light from the scintillator at the end of the detection unit P. It is possible to perform the radiation irradiation start detection process (reference B) and the erroneous detection process (reference C) shown in FIG.

  Specifically, the control means 22 is based on the detection method 1 described above, for example, when the radiation imaging apparatus 1 is irradiated with radiation, the TFT 8 of the normal radiation detection element 7 that can be irradiated with light from the scintillator 3. The normal leak data dleak read out via the detector is monitored and, instead of the leak data dleakA shown in FIG. 17, read out from the scintillator at the end of the detector P via the TFT 8B of the radiation detection element 7B. The leak data dleakB is also monitored.

  Then, according to the criteria shown in FIG. 17 (however, leak data dleak A and the like are read as leak data dleak B and the like), the leak data dleak B is set at the same time even when the normal leak data dleak exceeds the set threshold dleak_th. If it is equal to or greater than the threshold value bleakB_th, it is determined that there is a false detection due to the vibration or the like being applied to the radiation image capturing apparatus 1 (see criterion C).

  If the leak data dleakB is less than the set threshold value bleakB_th when the normal leak data dleak becomes equal to or higher than the set threshold value dleak_th, it is determined that the radiation imaging apparatus 1 has started irradiation with radiation. (Refer to the reference B), the image data D is read out after shifting to the charge accumulation state as shown in FIG.

[Modification 7]
Further, when the readout IC 16 incorporating the readout circuit 17 is provided by being incorporated on the film of the flexible circuit board 12 as shown in FIG. If applied, the flexible circuit board 12 may vibrate, and thereby the data output from the read IC 16 may become abnormally large.

  Therefore, using this, for example, the control means 22 is configured to monitor the signal read from the read circuit 17 in the read IC 16 to which the signal line 6 is not connected. 17 may be used instead of the leak data dleakA in FIG.

  Specifically, in this case, the control means 22 is such that the signal read from the read circuit 17 to which the signal line 6 is not connected is less than the set threshold value, and via the TFT 8 of each radiation detection element 7. Only when the leaked data dleak read out is equal to or greater than the set threshold value dleak_th, it is determined that radiation irradiation has started, and the irradiation start is detected (see criterion B in FIG. 17).

  In addition, even if the leak data dleak read through the TFT 8 of each radiation detection element 7 is equal to or greater than the set threshold value dleak_th, the signal read from the read circuit 17 to which the signal line 6 is not connected is also set. If it is equal to or greater than the threshold value, it is determined that the detection is false due to vibration or the like being applied to the radiation image capturing apparatus 1 (see criterion C in FIG. 17).

  As described above, when configured as in the above-described Modification 6 and Modification 7, the radiation detection functioning in the same manner as the radiation detection element 7A or the like shielded by the shielding means 42 without newly providing the shielding means 42. Radiation irradiation due to vibration applied to the radiographic imaging apparatus 1 using leak data dleakB read out through the TFT 8B of the element 7B, a signal read out from the readout circuit 17 to which the signal line 6 is not connected, etc. It is possible to accurately determine the erroneous detection of the start and the detection of the start of radiation irradiation with respect to the radiographic imaging apparatus 1.

  Therefore, even if it is configured as in Modification 6 or Modification 7, it is possible to obtain a beneficial effect similar to the effect in the present embodiment.

[Modification 8]
Furthermore, as in the basic configuration shown in FIG. 14, when the radiographic imaging apparatus 1 is configured to be provided with the current detection means 26 that detects the current flowing through the bias line 9 and the connection 10, the radiation imaging apparatus 1 is shielded by the shielding means 42. The current Ia flowing out from each radiation detection element 7A to the bias line 9 and the current I flowing out from the normal radiation detection element 7 not provided with the shielding means 42 to the bias line 9 are merged at the connection 10. .

  For this reason, the current detection means 26 cannot separate and detect them, and the reference shown in FIG. 17 cannot be applied.

  Therefore, for example, as shown in FIG. 24, the bias line 9 connected to the predetermined radiation detection element 7A shielded by the shielding means 42 and the bias line 9 connected to the other normal radiation detection element 7 are used. Are connected to separate connections 10A and 10B, and current detection means 26A and 26B are provided on the connections 10A and 10B, respectively.

  Then, each current detection means 26A, 26B is configured to detect the value of the current flowing through each of the connections 10A, 10B and output it to the control means 22, respectively. Then, the control means 22 applies the reference by replacing the leak data dleak, bleakA, etc. in the reference shown in FIG. 17 with the current value I detected by the current detection means 26A and the current value Ia detected by the current detection means 26B, respectively. .

  If comprised in this way, it will become possible to determine accurately and detect the start of radiation irradiation or erroneous detection in the radiographic imaging apparatus 1 based on the reference B or the reference C in the same manner as described above. .

[Image correction for line defects, etc.]
On the other hand, when configured as in the above-described embodiment and modifications 1 to 5 and 8, since each predetermined radiation detection element 7A is shielded by the shielding means 42, radiation and light do not reach, and a radiation image is obtained. Cannot shoot. Therefore, the image data D as the main image cannot be read from the predetermined radiation detection element 7A.

  Therefore, in the image data D read from each radiation detection element 7, for example, as shown in FIG. 25, the image data D exists in a portion corresponding to the signal line 6A to which each predetermined radiation detection element 7A is connected. The part which does not do, ie, what is called a line defect, inevitably occurs. Note that, when the predetermined radiation detection element 7A is formed in a dot-like state on the detection unit P as in the second modification, a portion where the image data D does not exist appears in a dot-like manner. That is, it becomes a so-called point defect state.

  Therefore, it is necessary to perform image correction for forming the image data D on the defective portion of the predetermined radiation detection element 7A.

  Therefore, in the present embodiment, a predetermined radiation detection element based on the transmitted image data D by the image processing apparatus (console 58 in the present embodiment) that has received the transmission of the image data D from the radiation image capturing apparatus 1. Image correction processing for forming image data D is performed for the 7A portion. The control means 22 of the radiographic image capturing apparatus 1 is configured to perform image correction processing for forming the image data D for a predetermined radiation detection element 7A before transmitting the image data D to the image processing apparatus. Is also possible.

  As a method of image correction processing for forming the image data D for the predetermined radiation detection element 7A, a known method can be used.

  That is, for example, as shown in FIG. 25, normal radiation detection connected to the signal lines 6a and 6b adjacent on the detection unit P with respect to the signal line 6A to which the predetermined radiation detection element 7A is connected. Based on the image data D read from the element 7, it is possible to form the image data D of a predetermined radiation detection element 7A portion.

  In this case, for example, an average value of the image data Da and Db (see FIG. 25) read from the normal radiation detection element 7 adjacent to a predetermined radiation detection element 7A is calculated, and the predetermined radiation detection element For example, the radiation detection elements 7 adjacent to each other in the left-right direction in FIG. Using each image data D read from each normal radiation detecting element 7 in the vicinity, it is possible to form the image data DA of the predetermined radiation detecting element 7A and correct the image.

  With this configuration, line defects and point defects that are inevitably generated in a portion of the predetermined radiation detection element 7A where the image data D as the main image cannot be read out are read from the normal radiation detection element 7. By using the image data D, it is possible to accurately perform image correction by newly forming the image data D in a line defect or point defect portion.

  And it becomes possible to generate | occur | produce a radiographic image exactly by performing image correction exactly with respect to the line defect and point defect which arise in the image data D in this way.

  It is needless to say that the present invention is not limited to the above-described embodiments and modifications, and can be appropriately changed without departing from the gist of the present invention.

DESCRIPTION OF SYMBOLS 1 Radiographic imaging apparatus 3 Scintillator 5 Scan line 6, 6A Signal line 7 Radiation detection element 7A Predetermined radiation detection element 7B Radiation detection element (radiation detection element which is not irradiated with light)
8 TFT (switch means)
9 Bias line 15 Scanning drive means 16 Reading IC
17, 17A Reading circuit 18 Amplifying circuit 18a Operational amplifier 18b Capacitor 22 Control means 26, 26A, 26B Current detection means 41 Antenna device (communication means)
42 Shielding means 50 Radiographic imaging system 58 Console (image processing device)
cf Capacity D Image data Da, Db Image data read from adjacent radiation detection elements d Image data (signal) for detecting irradiation start
dleak, dleakA Leak data (signal)
dleak_th threshold value (threshold value set for a radiation detection element not provided with shielding means)
dleak_th threshold value (threshold value set for a predetermined radiation detection element)
I, Ia Current value (signal)
P detector q charge

Claims (13)

A detection unit comprising a plurality of scanning lines and a plurality of signal lines, and a plurality of radiation detection elements arranged two-dimensionally;
Scanning drive means for switching on and applying an on-voltage and an off-voltage to each scanning line;
Switch means connected to each of the scanning lines and causing the signal lines to discharge charges accumulated in the radiation detection element when an on-voltage is applied;
A readout circuit that converts the electric charge emitted from the radiation detection element into image data and reads the image data;
A detection process for detecting the start of radiation irradiation is performed based on a signal that changes due to the irradiation of radiation, and at least the scanning drive unit and the readout circuit are detected after detection of the start of radiation irradiation. Control means for controlling and reading out the electric charges emitted from the respective radiation detection elements as image data,
With
Among the radiation detection elements, the predetermined radiation detection elements are provided with shielding means for shielding the radiation detection elements from being irradiated with light or radiation,
The control means is configured to set the signal related to the radiation detection element in which the signal related to the predetermined radiation detection element shielded by the shielding means is less than a set threshold and the shield means is not provided. A radiographic imaging apparatus characterized by determining that irradiation of radiation has started and detecting the start of irradiation only when the threshold is equal to or greater than the threshold value.   In the detection process, the control means applies each of the radiation detection elements via the switch means in a state where an off voltage is applied to the scan lines from the scan driving means to turn off the switch means. The radiographic image capturing apparatus according to claim 1, wherein a leak data read process for reading out the electric charge leaked as a leak data is repeatedly performed, and the detection process is performed using the read leak data as the signal.   In the detection process, the control means sequentially applies an on-voltage from the scan driving means to the scan lines, repeatedly causes the radiation detection elements to read out image data for detecting the start of irradiation, The radiographic image capturing apparatus according to claim 1, wherein the detection process is performed using the image data for detecting irradiation start as the signal.   The predetermined radiation in which all or some of the plurality of radiation detection elements connected to one or more predetermined signal lines of all the signal lines are shielded by the shielding means. The radiographic image capturing apparatus according to claim 1, wherein the radiographic image capturing apparatus is a detection element.   The shielding means is provided so as to shield the predetermined radiation detection element connected to the signal line wired in the center on the detection unit among the signal lines. The radiographic imaging device according to any one of claims 1 to 4.   The shielding means is provided so as to shield the predetermined radiation detection element connected to the signal line wired at an end on the detection unit among the signal lines. The radiographic imaging device according to any one of claims 1 to 4. The amplification circuit of the readout circuit is composed of a charge amplifier circuit including an operational amplifier and a capacitor connected in parallel to the operational amplifier.
The capacitor of the amplification circuit of the readout circuit connected to the signal line to which the predetermined radiation detection element shielded by the shielding means is connected is connected to the other radiation detection element. 7. The device according to claim 1, wherein the capacitance is set to be smaller than a capacitance of a capacitor of an amplifier circuit of the readout circuit connected to the signal line. 8. Radiation imaging device.   The capacitance of the capacitor of the amplifier circuit of the readout circuit is larger than that of the readout IC including only the readout circuit to which the signal line to which the radiation detection element not provided with the shielding unit is connected is connected. The readout circuit having the readout circuit connected to the signal line to which the predetermined radiation detection element shielded by the shielding means is connected is set to have a small capacity. The radiographic imaging device according to claim 7.   The capacity of the capacitor of the amplification circuit of the readout circuit set to a small capacity at the time of detection processing of the start of irradiation of radiation is returned to a larger capacity at the time of the readout processing of the image data. The radiographic imaging apparatus of Claim 7 or Claim 8. It has a scintillator that converts the irradiated radiation into light,
The radiation detection element that is not irradiated with light from the scintillator is provided at an end of the detection unit,
Instead of providing the shielding means, the control means may be configured to detect the radiation detection element in which the signal related to the radiation detection element that is not irradiated with light from the scintillator is less than a set threshold value and the light may be irradiated from the scintillator. 2. The radiographic image capturing apparatus according to claim 1, wherein the radiation start is detected by determining that the irradiation of radiation is started only when the signal regarding is equal to or greater than a set threshold value. The readout circuit to which the signal line is not connected is provided;
Instead of providing the shielding means, the control means is configured such that the signal read from the readout circuit to which the signal line is not connected is less than a set threshold value, and the radiation detection elements are connected. Only when the signal read from the readout circuit to which the signal line is connected is equal to or higher than a set threshold value, it is determined that radiation irradiation has started, and the irradiation start is detected. The radiographic imaging device according to claim 1. Each radiation detection element is connected to a bias line for applying a reverse bias voltage to the radiation detection element,
Current flowing through the bias line is detected by a bias line connected to the predetermined radiation detection element shielded by the shielding means and a bias line connected to the other radiation detection element. Current detection means are provided,
The radiographic imaging apparatus according to claim 1, wherein the control unit performs the detection process using the current value detected by each of the current detection units as the signal. The radiographic imaging apparatus according to any one of claims 1 to 12, comprising a communication unit,
An image processing device that generates a radiographic image based on the image data transmitted from the radiographic imaging device via the communication unit;
With
In the radiographic imaging apparatus, the image processing apparatus is configured to detect the image data of the predetermined radiation detection element portion shielded by the shielding unit, and each of the radiations adjacent to the predetermined radiation detection element on the detection unit. A radiographic imaging system, wherein the image data of the predetermined radiation detection element portion is formed using the image data read from the detection element and image correction is performed.

Images