JP2020089656A - Radiation imaging apparatus and control method therefor - Google Patents

Abstract

To provide a mechanism for suppressing erroneous determination regarding a start of radiation irradiation.SOLUTION: A radiation imaging apparatus according to the present invention comprises: a first arithmetic unit 150 for outputting first radiation information by arithmetically processing first current information including a time variation of a current flowing through a bias wiring when a bias voltage is supplied to a first two-dimensional detector 111 through the bias wiring; a second arithmetic unit 160 for outputting second radiation information by arithmetically processing second current information including a time variation of a current flowing through the bias wiring when a bias voltage is supplied to a second two-dimensional detector 121 through the bias wiring; and a third arithmetic unit 170 for determining whether or not radiation start determination performed by a first drive control unit 130 and radiation start determination performed by a second drive control unit 140 are properly made by arithmetically processing the first current information and the second current information.SELECTED DRAWING: Figure 1

Description

The present invention relates to a radiation imaging apparatus and a control method thereof.

2. Description of the Related Art Currently, a flat panel detector (Flat Panel), which is a two-dimensional detector formed of a semiconductor material, is used as a radiographic apparatus used for medical image diagnosis by radiation such as X-rays and non-destructive inspection.
Radiation imaging devices using a detector (FPD) have become widespread. Such a radiation imaging apparatus is used, for example, in medical image diagnosis as a digital radiation imaging apparatus for still image photographing such as general photographing and moving image photographing such as fluoroscopic photographing. A method of acquiring a plurality of radiation images using radiation having different energy components using such a radiation imaging apparatus, and acquiring an energy subtraction image in which a specific subject portion is separated or emphasized from the difference between the acquired radiation images. It has been known.

In such a radiation imaging apparatus, the radiation generating apparatus and the FPD are generally synchronized. However, when the FPD is installed, it is necessary to connect the FPD to the radiation generator, and thus there is a problem that the installation place is limited. Therefore, as a means to eliminate the need for splicing, the start of radiation is detected by detecting the change in the electric charge of the sensor pixel and the change in the current and voltage of the two-dimensional detector that changes with the increase of the radiation emitted from the radiation generator. It is known how to do it.

For example, U.S. Pat. No. 6,037,009 discloses an imaging device arranged to be biased to form a pixel detector, and a bias monitor for monitoring the bias to determine the radiation incident on the pixel detector. An apparatus comprising the means is disclosed.

Further, in Patent Document 2, in an apparatus capable of acquiring an energy subtraction image, as a method of eliminating a connection with a radiation generating apparatus, an electric signal output from a radiation detector on the side of the radiation generating apparatus during a reset operation is used. Based on this, there is disclosed a technique of transmitting a storage start instruction to the control unit when the predetermined threshold is exceeded.

JP, 2010-212925, A JP, 2018-15454, A

When the bias is supplied to the two-dimensional detector, noise may be mixed in the bias current due to factors other than radiation irradiation. If this noise is large, there is a possibility that the start of irradiation of radiation may be erroneously determined even though the radiation has not been irradiated. And
In the configuration in which the radiation generation device and the two-dimensional detector are not synchronized, when the start of irradiation of radiation is determined, the operation shifts to the imaging operation. After that, there may occur a problem that a non-shooting period occurs until the next shooting preparation is completed. In this respect, it is difficult for the techniques described in Patent Document 1 and Patent Document 2 described above to suppress erroneous determinations regarding the start of radiation irradiation.

The present invention has been made in view of such problems, and an object thereof is to provide a mechanism for suppressing an erroneous determination regarding the start of irradiation of radiation.

A radiation imaging apparatus of the present invention detects a radiation and outputs a first image information, and a first two-dimensional detector, and a second two-dimensional detector that detects the radiation transmitted through the first two-dimensional detector. A second two-dimensional detector for outputting image information, and a first current information including a time variation of a current flowing through the bias wiring while supplying a bias voltage to the first two-dimensional detector through a bias wiring. And a second bias power supply that supplies a bias voltage to the second two-dimensional detector through a bias wiring and outputs second current information including time variation of the current flowing through the bias wiring. A first arithmetic means for arithmetically processing the first current information to output first radiation information including a time variation of the intensity of the radiation; and a second arithmetic information for arithmetically processing the second current information. Of the second radiation information including the time variation of the intensity of the radiation, and the start of irradiation of the radiation is determined by using the first radiation information, and the first two-dimensional detector First drive control means for controlling the drive, and second drive control means for determining the start of irradiation of the radiation using the second radiation information and controlling the drive of the second two-dimensional detector. And the first current information and the second current information are arithmetically processed so that the start determination by the first drive control means and the start determination by the second drive control means are proper determinations. And a third calculation means for determining whether there is any.
The present invention also includes the method for controlling the radiation imaging apparatus described above.

According to the present invention, it is possible to suppress erroneous determinations regarding the start of radiation irradiation.

It is a figure which shows an example of schematic structure of the radiation imaging system containing the radiation imaging device which concerns on the 1st Embodiment of this invention. It is a figure which shows an example of the equivalent circuit which concerns on the internal structure of the 1st radiation imaging panel shown in FIG. It is a figure which shows an example of the laminated constitution of the 1st two-dimensional detector and the 2nd two-dimensional detector shown in FIG. It is a figure which shows an example of the equivalent circuit which concerns on the internal structure of the 1st bias power supply and the 2nd bias power supply shown in FIG. It is a flow chart which shows a comparative example and shows an example of a processing procedure of a control method which judges the start and end of radiation irradiation using one two-dimensional detector. The flowchart which shows the control method of the radiation imaging device which concerns on the 1st Embodiment of this invention, and shows an example of the processing procedure of the control method which determines the start and end of radiation irradiation using two two-dimensional detectors. is there. 1 shows a method for controlling a radiation imaging apparatus according to a first embodiment of the present invention, in which a first drive control unit and a second drive control unit shown in FIG. 6 is a timing chart showing an example of drive timing of a detector. 3 is a timing chart showing a control method of the radiation imaging apparatus according to the first exemplary embodiment of the present invention and showing an example of drive timing of each component of the radiation imaging apparatus. The control method of the radiation imaging device which concerns on the 2nd Embodiment of this invention is shown, The 1st two-dimensional detector by the 1st drive control unit and the 2nd drive control unit shown in FIG. 6 is a timing chart showing an example of drive timing of a detector. 6 is a timing chart showing a control method of the radiation imaging apparatus according to the second exemplary embodiment of the present invention and showing an example of drive timing of each component of the radiation imaging apparatus. The 2nd two-dimensional detector and 2nd two-dimensional detector by the 1st drive control unit and the 2nd drive control unit which show the control method of the radiation imaging device which concerns on the 3rd Embodiment of this invention are shown. 6 is a timing chart showing an example of drive timing of a detector. 9 is a timing chart showing a control method of the radiation imaging apparatus according to the third exemplary embodiment of the present invention and showing an example of drive timings of respective components of the radiation imaging apparatus.

Hereinafter, modes (embodiments) for carrying out the present invention will be described with reference to the drawings. At this time, in the following description and drawings, common reference numerals are given to common configurations in a plurality of drawings. Therefore, common configurations will be described with reference to a plurality of drawings, and descriptions of configurations with common reference numerals will be appropriately omitted. In addition, in the radiation in the present invention, in addition to α-rays, β-rays, γ-rays, etc., which are beams produced by particles (including photons) emitted by radiation decay, a beam having an energy of about the same or more, for example, X It can also include rays, particle rays, cosmic rays, and so on.

(First embodiment)
First, a first embodiment of the present invention will be described.

FIG. 1 is a diagram showing an example of a schematic configuration of a radiation imaging system 10 including a radiation imaging apparatus 100 according to the first embodiment of the present invention. As shown in FIG. 1, the radiation imaging system 10 includes a radiation imaging apparatus 100, a computer 200, a radiation control apparatus 300, and a radiation generation apparatus 400.

The radiation generation device 400 starts irradiation of the radiation 401 under the control of the radiation control device 300. The radiation 401 emitted from the radiation generation device 400 passes through the inspection target T and enters the radiation imaging device 100. Further, the radiation generation device 400 ends the irradiation of the radiation 401 under the control of the radiation control device 300.

The radiation imaging apparatus 100 is an apparatus that detects the radiation (including the radiation that has passed through the inspection target T) 401 radiated from the radiation generation apparatus 400 and outputs image information related to radiation imaging. The radiation imaging apparatus 100 of FIG. 1 includes a first radiation imaging panel 110, a second radiation imaging panel 120, a first drive control unit 130, a second drive control unit 140, a first calculation unit 150, and a second calculation unit 150. The calculation unit 160 and the third calculation unit 170 are included.

The first radiation imaging panel 110 includes a first two-dimensional detector 111 and a first bias power supply 112. The first two-dimensional detector 111 is provided with a plurality of sensor pixels two-dimensionally (for example, in a matrix of X columns×Y rows), and detects the incident radiation 401 by the plurality of sensor pixels to detect the first radiation 401. The image information of is output to the computer. The first bias power supply 112 supplies a bias voltage to the first two-dimensional detector 111 through a bias wiring and outputs first current information including a time variation of a current (current amount) flowing through the bias wiring.

The second radiation imaging panel 120 includes a second two-dimensional detector 121 and a second bias power source 122. The second two-dimensional detector 121 has a plurality of sensor pixels arranged two-dimensionally (for example, in a matrix of X columns×Y rows), and the plurality of sensor pixels transmit the first two-dimensional detector 111. The detected radiation 401 is detected and the second image information is output to the computer. The second bias power supply 122 supplies a bias voltage to the second two-dimensional detector 121 through the bias wiring and outputs second current information including the time variation of the current (current amount) flowing through the bias wiring.

The first calculation unit 150 performs a calculation process on the first current information output from the first bias power supply 112, and outputs the first radiation information including the time variation of the radiation intensity.

The first drive control unit 130 controls the drive timing of the first two-dimensional detector 111 based on the drive method requested by the computer 200. Then, the first drive control unit 130 uses the first radiation information output from the first calculation unit 150 to perform the radiation start determination regarding the irradiation of the radiation 401, and appropriately changes the driving method. , And controls the drive timing of the first two-dimensional detector 111.

The second arithmetic unit 160 arithmetically processes the second current information output from the second bias power source 122, and outputs the second radiation information including the time variation of the radiation intensity.

The second drive control unit 140 controls the drive timing of the second two-dimensional detector 121 based on the drive method requested by the computer 200. Then, the second drive control unit 140 performs the radiation start determination relating to the irradiation of the radiation 401 using the second radiation information output from the second calculation unit 160, and appropriately changes the driving method. , And controls the drive timing of the second two-dimensional detector 121.

The third arithmetic unit 170 arithmetically processes the first current information output from the first bias power source 112 and the second current information output from the second bias power source 122 to perform the first drive control. It is determined whether the radiation start determination by the unit 130 and the radiation start determination by the second drive control unit 140 are proper determinations.

The computer 200 performs various controls and various processes. For example, the computer 200 controls the radiation imaging apparatus 100 and acquires image information (the above-described first image information and second image information) from the radiation imaging apparatus 100.

The radiation control device 300 controls the irradiation of the radiation generated from the radiation generation device 400. For example, the radiation control device 300 performs various controls including the start and end of irradiation of radiation generated from the radiation generation device 400, the dose of irradiation radiation, the irradiation time, and the like.

As the first to third arithmetic units 150 to 170, it is preferable to use digital signal processing circuits such as FPGA, DSP, and processor, but analog circuits such as sample hold circuits and operational amplifiers are used. You may make it comprised. Further, although FIG. 1 shows an example in which the first to third arithmetic units 150 to 170 are included as one configuration of the radiation imaging apparatus 100, they may be configured inside the computer 200, for example.

FIG. 2 is a diagram showing an example of an equivalent circuit according to the internal configuration of the first radiation imaging panel 110 shown in FIG. In FIG. 2, the same components as those in FIG. 1 are designated by the same reference numerals.

The first radiation imaging panel 110 includes a first two-dimensional detector 111, a first bias power supply 112, a Vs generation circuit 113, a first shift register 114, a first readout circuit 115, and a first buffer amplifier 116. , And a first A/D converter 117.

The first two-dimensional detector 111 is configured by arranging a plurality of sensor pixels 1110 including a conversion element 1111 and a switch element 1112 in a two-dimensional shape (for example, a matrix shape of X columns×Y rows). Specifically, FIG. 2 shows an example in which the sensor pixels 1110 of 3 columns×3 rows are arranged in the first two-dimensional detector 111 for simplification of description, but in an actual radiation imaging panel, A form in which more sensor pixels are arranged is adopted. For example, in the 17-inch radiation imaging panel 110, about 2800 columns×about 2800 rows of sensor pixels can be arranged.

The conversion element 1111 is a direct conversion element that directly converts incident radiation into an electric signal or an indirect conversion element (photoelectric conversion element) that converts light converted from radiation in the scintillator layer into an electric signal. .. When a photoelectric conversion element is used as the conversion element 1111, the scintillator layer is disposed on the radiation incident side of the photoelectric conversion element and is configured as a phosphor that converts the incident radiation into light in a wavelength band that the photoelectric conversion element can detect. .. Here, in this embodiment, an example in which a photoelectric conversion element is applied as the conversion element 1111 will be described. In this embodiment, as the photoelectric conversion element applied as the conversion element 1111, an example of using a MIS type photodiode which is arranged on an insulating substrate such as a glass substrate and has amorphous silicon as a main material will be described. But it is okay.

The switch element 1112 outputs an electric signal according to the electric charge accumulated in the conversion element 1111. A transistor having a control terminal and two main terminals is preferably used as the switch element 1112, and a thin film transistor (TFT) is used in this embodiment. One electrode of the conversion element 1111 is electrically connected to one of the two main terminals of the switch element 1112, and the other electrode of the conversion element 1111 is electrically connected to the first bias power source 112 via a common bias wiring. Connected to each other.

A plurality of switch elements 1112 in the row direction, for example, T11 to T13, have their control terminals electrically connected in common to the drive wiring Vg1 in the first row, and the shift elements 114 to 1112 are connected from the shift register 114, which is a drive circuit. A drive signal for controlling the conduction state of is supplied in units of rows via the drive wiring Vg. In addition, while the plurality of switch elements 1112 in the column direction, for example, T11 to T31, the other main terminal is electrically connected in common to the signal wiring Sig1 in the first column, and the switch element 1112 is in the conductive state. Then, an electric signal corresponding to the charge of the conversion element 1111 is output to the read circuit 115 via the signal wiring Sig. The plurality of signal lines Sig1 to Sig3 arranged in the column direction of the sensor pixel 1110 transmit the electric signals output from the plurality of sensor pixels 1110 to the readout circuit 115 in parallel.

The first readout circuit 115 is provided corresponding to each signal wiring Sig, and an amplification circuit 1150 that amplifies an electric signal output in parallel from the first two-dimensional detector 111, a reference power supply 1154, and a multiplexer 1155. Is configured. Each amplifier circuit 1150 includes an integrating amplifier 1153 that amplifies the output electric signal, a variable amplifier 1151 that amplifies the electric signal from the integrating amplifier 1153, and a sample hold circuit 1152 that samples and holds the amplified electric signal. Has been done.

The integrating amplifier 1153 is configured to include an operational amplifier that amplifies and outputs the read electrical signal, an integrating capacitor, and a reset switch. The integrating amplifier 1153 can change the amplification factor by changing the value of the integrating capacitance. The output electric signal is input to the inverting input terminal of the operational amplifier included in the integrating amplifier 1153, and the reference voltage Vref from the reference power supply 1154 is input to the non-inverting input terminal of the operational amplifier. The amplified electric signal is output. Here, the reference power supply 1154 is a power supply for supplying the reference voltage Vref to the non-inversion input terminal of each operational amplifier. In addition, the integrating capacitance included in the integrating amplifier 1153 is arranged between the inverting input terminal and the output terminal of the operational amplifier.

The sample hold circuit 1152 is provided corresponding to each amplifier circuit 1150 and includes a sampling switch and a sampling capacitor.

The multiplexer 1155 sequentially outputs the electric signals read in parallel from the respective amplifier circuits 1150 and outputs the electric signals to the first buffer amplifier 116 as a serial image signal.

The first buffer amplifier 116 impedance-converts the image signal output from the multiplexer 1155 and outputs the image signal (Vout) that is an analog electric signal to the first A/D converter 117.

The first A/D converter 117 converts the image signal (Vout), which is an analog electric signal output from the first buffer amplifier 116, into a digital image signal, and converts this into image information (first Image information) to the computer 200.

The first bias power supply 112 supplies the bias voltage Vs to the other electrode of each conversion element 1111 in common via the bias wiring, and the first current information including the time variation of the amount of current supplied to the bias wiring. Is output. As shown in FIG. 2, the first bias power supply 112 includes a current-voltage conversion circuit 1121 including an operational amplifier and a resistor, and an A/D converter that converts the output voltage of the current-voltage conversion circuit 1121 into a digital value. 1124 is included. In the example shown in FIG. 2, an example in which a current-voltage conversion circuit including an operational amplifier and a resistor is applied as the current-voltage conversion circuit 1121 is shown, but the present embodiment is not limited to this, and for example, Alternatively, a current-voltage conversion circuit using a shunt resistor may be used. Further, in the example shown in FIG. 2, the first bias power supply 112 shows an example in which the output voltage of the current-voltage conversion circuit 1121 is converted into a digital value by the A/D converter 1124, but in the present embodiment, this is used. However, the output voltage of the current-voltage conversion circuit 1121 may be output as it is. Further, the first bias power supply 112 may output, as the first current information, information on a physical quantity corresponding to the amount of current supplied to the bias wiring (Bs).

The Vs generation circuit 113 is a circuit that generates the bias voltage Vs to be output to the current-voltage conversion circuit 1121.

The first shift register 114 brings the switch element 1112 into a conductive state in response to a control signal (D-CLK, OE, DIO) relating to drive timing input from the first drive control unit 130 shown in FIG. A drive signal having a conduction voltage Vcom and a non-conduction voltage Vss that is in a non-conducting state is output to each drive wiring Vg. Accordingly, the first shift register 114 controls the conducting state and the non-conducting state of the switch element 1112, and drives the first two-dimensional detector 111. Here, the control signal D-CLK is a shift clock signal of the first shift register 114 used as a drive circuit, the control signal DIO is a pulse signal transferred by the first shift register 114, and the control signal OE is This is a signal for controlling the output end of the first shift register 114.

As described above, the required driving time and the scanning direction are set. Further, the first drive control unit 130 controls the operation of each component of the read circuit 115 by supplying the control signal RC, the control signal SH, and the control signal CLK to the read circuit 115. Here, the control signal RC is a signal that controls the operation of the reset switch of the integrating amplifier described above, the control signal SH is a signal that controls the operation of the sample hold circuit 1152, and the control signal CLK is the operation of the multiplexer 1155. This is a control signal.

In the above description in FIG. 2, the first radiation imaging panel 110 is described, but the second radiation imaging panel 120 shown in FIG. 1 may have the same configuration. That is, the second radiation imaging panel 120 includes the second two-dimensional detector 121, the second bias power supply 122, the Vs generation circuit 113, the second shift register 124, the second readout circuit 125, and the second buffer. The amplifier 126 and the second A/D converter 127 may be included in the configuration. In this case, the internal configuration of the second two-dimensional detector 121 can be the same as the internal configuration of the first two-dimensional detector 111 described above. Further, the second bias power source 122 can have the same configuration as the internal configuration of the first bias power source 112 described above. Further, the second shift register 124 can have the same function as that of the first shift register 114 described above. The second read circuit 125 can have the same configuration as the internal configuration of the first read circuit 115 described above. In addition, the second buffer amplifier 126 can have the same function as that of the first buffer amplifier 116 described above. Further, the second A/D converter 127 can have the same function as that of the first A/D converter 117 described above. Here, in the example illustrated in FIG. 2, the second radiation imaging panel 120 uses the Vs generation circuit 113 that is common to the first radiation imaging panel 110, but the present embodiment is not limited to this. It is not something that will be done. In the second radiation imaging panel 120, a mode in which the Vs generation circuit 123 corresponding to the Vs generation circuit 113 of the first radiation imaging panel 110 is separately configured is also applicable to this embodiment.

FIG. 3 is a diagram showing an example of a laminated structure of the first two-dimensional detector 111 and the second two-dimensional detector 121 shown in FIG.

As shown in FIG. 3, in the present embodiment, the first two-dimensional detector 111 is arranged on the side on which the radiation 401 is incident, and the second two-dimensional detection is on the side opposite to the side on which the radiation 401 is incident. The container 121 is arranged.

The first two-dimensional detector 111 includes a first glass substrate 311, a first sensor pixel 312, a first scintillator layer 313, and a first moisture barrier in order from the side opposite to the side on which the radiation 401 is incident. A layer (Al sheet) 314 is provided.

In addition, the second two-dimensional detector 121 includes a second glass substrate 321, a second sensor pixel 322, a second scintillator layer 323, and a second scintillator layer 323 in order from the side opposite to the side on which the radiation 401 is incident. The moisture-proof layer (Al sheet) 324 is provided.

Here, the first sensor pixel 312 corresponds to the sensor pixel 1110 of the first two-dimensional detector 111 shown in FIG. 2, and the second sensor pixel 322 is the second pixel shown in FIG. The two-dimensional detector 121 corresponds to the sensor pixel 1110.

The conversion elements 1111 included in the sensor pixel 312 and the sensor pixel 322 illustrated in FIG. 3 are arranged on the glass substrate 311 and the glass substrate 321 having an insulating property that transmit light emitted from the scintillator layer 313 and the scintillator layer 323, respectively. .. The sensor pixel 312 and the sensor pixel 322 may be formed by sequentially stacking a conductive layer, an insulating layer, a semiconductor layer, an impurity semiconductor layer, and a conductive layer over a glass substrate 311 and a glass substrate 321, respectively. Hereinafter, each layer will be described in the order of stacking. The conductive layer forms, for example, a gate electrode of a transistor (for example, TFT) included in the switch element 1112 shown in FIG. Further, the insulating layer is arranged, for example, so as to cover the conductive layer, and the semiconductor layer is arranged, for example, on a portion of the conductive layer that constitutes the gate electrode via the insulating layer. Further, the impurity semiconductor layer is arranged on the semiconductor layer so as to form, for example, two main terminals (source and drain) of the transistor included in the switch element 1112 shown in FIG. The conductive layer forms, for example, a wiring pattern connected to two main terminals (source and drain) of a transistor that forms the switch element 1112. Further, a part of the conductive layer constitutes the signal wiring Sig, and the other part constitutes a wiring pattern for connecting the conversion element 1111 and the switch element 1112.

The sensor pixel 312 and the sensor pixel 322 each further include an interlayer insulating film that covers the insulating layer and the conductive layer. The interlayer insulating film is provided with a contact plug for connecting to a portion of the conductive layer that constitutes the switch element 1112. Further, the sensor pixel 312 and the sensor pixel 322 may each have the conversion element 1111 disposed on the interlayer insulating film. The conversion element 1111 is configured as an indirect photoelectric conversion element that converts light converted from radiation in the scintillator layer (313 or 323) into an electric signal. The conversion element 1111 includes a conductive layer, an insulating layer, a semiconductor layer, an impurity semiconductor layer, a conductive layer, and an electrode layer which are stacked on the interlayer insulating film. Then, a protective layer and an adhesive layer are arranged on the conversion element 1111. In addition, the scintillator layer 313 and the scintillator layer 323 are arranged on the adhesive layer so as to cover the radiation incident surfaces of the glass substrate 311 and the glass substrate 321, respectively. In addition, each of the conductive layers constitutes a lower electrode of the conversion element 1111. In addition, the conductive layer and the electrode layer form an upper electrode of each conversion element 1111. The conductive layer, the insulating layer, the semiconductor layer, the impurity semiconductor layer, and the conductive layer form a MIS type sensor as the conversion element 1111. For example, the impurity semiconductor layer is formed of an n-type impurity semiconductor layer.

The scintillator layer 313 and the scintillator layer 323 can be formed using a material such as GOS (gadolinium oxysulfide) or CsI (cesium iodide). These materials can be formed by bonding, printing, vapor deposition, or the like. The same material may be used for the first scintillator layer 313 and the second scintillator layer 323, or different materials may be used depending on the energy of the acquired radiation. Further, in the present embodiment, the conversion element 1111 shows an example in which a MIS type sensor is used, but the present invention is not limited to this, and may be, for example, a pn type or PIN type photodiode. ..

The low energy component of the radiation 401 incident on the first two-dimensional detector 111 is absorbed by the first scintillator layer 313 covering the incident surface side of the first two-dimensional detector 111, and becomes visible light. It is converted and is incident on the respective first sensor pixels 312. On the other hand, in the radiation 401, a high-energy component that has not been absorbed by the first scintillator layer 313 of the first two-dimensional detector 111 passes through the first two-dimensional detector 111, and becomes a second two-dimensional detector. It is absorbed by the second scintillator layer 323 of the detector 121 and converted into visible light. Then, the light converted from the high energy component of the radiation 401 is incident on the second sensor pixel 322 of the second two-dimensional detector 121.

In this way, the first sensor pixel 312 of the first two-dimensional detector 111 obtains an electric signal due to the low energy component of the radiation 401. Further, in the second sensor pixel 322 of the second two-dimensional detector 121, an electric signal resulting from the component of the radiation 401 having high energy is obtained. That is, it is possible to acquire image information having different energies of the radiation 401 from the two two-dimensional detectors 111 and 121 by one exposure of the radiation 401. Specifically, the low energy image information based on the low energy component of the radiation 401 is obtained from the first two-dimensional detector 111, and the energy of the radiation 401 is detected from the second two-dimensional detector 121. High energy image information based on high components is obtained. Then, the computer 200 may, for example, the low-energy image information that is the first image information output from the first two-dimensional detector 111 and the second image output from the second two-dimensional detector 121. The energy subtraction image information (energy sub image information) can be acquired by performing the energy subtraction process using the high energy image information which is the information.

FIG. 4 is a diagram showing an example of an equivalent circuit according to the internal configuration of the first bias power supply 112 and the second bias power supply 122 shown in FIG. 4, the same components as those shown in FIG. 2 are designated by the same reference numerals.

The first bias power supply 112 includes a first current-voltage conversion circuit 1121, a first voltage amplification circuit 1122, a first band limiting circuit 1123, and a first A/D converter 1124. Has been done. The first bias power source 112 detects the current I_Vs of the bias wiring commonly connected to the other electrode of the conversion element 1111 of the first two-dimensional detector 111, and uses this as the first current information 410. Output.

The second bias power source 122 includes a second current-voltage conversion circuit 1221, a second voltage amplification circuit 1222, a second band limiting circuit 1223, and a second A/D converter 1224. Has been done. The second bias power supply 122 detects the current I_Vs′ of the bias wiring commonly connected to the other electrode of the conversion element 1111 of the second two-dimensional detector 121, and outputs this as the second current information 420. Output as.

The first current-voltage conversion circuit 1121 and the second current-voltage conversion circuit 1221 are each configured to have a transimpedance amplifier TA, a feedback resistor Rf, and a phase compensation capacitance Cf1. The Vs generating circuit 113 is connected to the non-inverting input terminal of the transimpedance amplifier TA, and one of the bias wirings of each bias wiring is connected to the inverting input terminal. A feedback resistor Rf is connected between the output terminal and the inverting input terminal of the transimpedance amplifier TA. Further, a phase compensating capacitor Cf is connected in parallel with the transimpedance amplifier TA.

The first voltage amplification circuit 1122 is a circuit that amplifies the output voltage of the first current-voltage conversion circuit 1121, and the second voltage amplification circuit 1222 outputs the output of the second current-voltage conversion circuit 1221. It is a circuit that amplifies the voltage. The first voltage amplification circuit 1122 and the second voltage amplification circuit 1222 are each configured to have an instrumentation amplifier IA and a gain setting resistor Rg.

The first band limiting circuit 1123 is a circuit for reducing noise in the output voltage amplified by the first voltage amplifying circuit 1122, and the second band limiting circuit 1223 is a second voltage amplifying circuit. This is a circuit for reducing noise in the output voltage amplified by 1222.

The first A/D converter 1124 converts the analog signal from the first band limiting circuit 1123 into a digital signal and outputs it as the first current information 410. Similarly, the second A/D converter 1224 converts the analog signal from the second band limiting circuit 1223 into a digital signal and outputs this as the second current information 420.

With the configuration shown in FIG. 4, the first bias power source 112 converts the current flowing in each bias wiring of the first two-dimensional detector 111 into a voltage, amplifies it, band-limits it, and obtains it by A/D conversion. By outputting the current information 410 of 1, the current flowing in each bias wiring is detected. Similarly, the second bias power source 122 converts the current flowing in each bias wiring of the second two-dimensional detector 121 into a voltage, amplifies it, band-limits it, and A/D-converts it to obtain second current information. By outputting 420, the current flowing through each bias wiring is detected.

The first current information 410 output from the first bias power supply 112 is used when the first radiation information is calculated by the first calculation unit 150, and the first radiation information is used as the first drive control. It is used for the start determination and the end determination of the irradiation of the radiation 401 in the unit 130. Further, the second current information 420 output from the second bias power source 122 is used when the second radiation information is calculated by the second calculation unit 160, and this second radiation information is the second radiation information. It is used for the start determination and the end determination of the irradiation of the radiation 401 in the drive control unit 140. Further, the first current information 410 output from the first bias power supply 112 and the second current information 420 output from the second bias power supply 122 are used in the third drive unit 160 in the first drive control. The judgments in the unit 130 and the second drive control unit 140 are used in judging whether the judgments are proper.

FIG. 5 is a flowchart showing a comparative example and showing an example of a processing procedure of a control method for performing start determination and end determination of irradiation of the radiation 401 using one two-dimensional detector. Here, in the description of the flowchart of FIG. 5, an example in which the first two-dimensional detector 111 is applied as the one two-dimensional detector will be described.

First, in step S101, the first drive control unit 130 uses the radiation information output by the first calculation unit 150 to determine whether or not a radiation start determination that determines that irradiation of the radiation 401 has started has been performed. To do. Here, as the radiation start determination, a method of determining that the radiation irradiation is started when the radiation information exceeds a predetermined threshold value is preferably used.

As a result of the determination in step S101, when the radiation start determination is not performed (S101/NO), the process proceeds to step S102.
In step S102, the first drive control unit 130 drives the first two-dimensional detector 111 to remove charges generated by accumulation of dark current (hereinafter, referred to as “idle reading”). Let it be done. Here, the blank reading is sequentially performed from the first line (0th line) to the last line (Y-1th line), and when the last line is reached, the process returns to the first line.

On the other hand, as a result of the determination in step S101, when the radiation start determination is performed (S101/YES), the process proceeds to step S103.
In step S103, the first drive control unit 130 determines whether or not the radiation end determination that determines that the irradiation of the radiation 401 has been completed is performed. Here, as the radiation end determination, a method of determining that the irradiation of the radiation has ended when a predetermined time has elapsed after performing the radiation start determination is preferably used, but, for example, the radiation information is predetermined. If the threshold value is less than the threshold value, the radiation end determination may be performed.

As a result of the determination in step S103, when the radiation end determination is not performed (S103/NO), the process proceeds to step S104.
Proceeding to step S104, the first drive control unit 130 drives the first two-dimensional detector 111 so that the switch elements 1112 of all the sensor pixels are made non-conducting and a signal due to radiation is accumulated (hereinafter, referred to as “drive”). (Referred to as “accumulation”).

On the other hand, as a result of the determination in step S103, when the radiation end determination is performed (S103/YES), the process proceeds to step S105.
In step S105, the first drive control unit 130 drives the first two-dimensional detector 111 to read out an electric signal corresponding to the electric charge generated by the accumulation of radiation (hereinafter, referred to as “main reading”). ). This main reading is performed in order from the first line to the last line. When the main reading reaches the last line, the series of shooting operations ends, and the processing of the flowchart in FIG. 5 ends.

FIG. 6 shows a control method of the radiation imaging apparatus 100 according to the first embodiment of the present invention, which uses two two-dimensional detectors 111 and 121 to perform a start determination and an end determination of irradiation of the radiation 401. 4 is a flowchart showing an example of the processing procedure of FIG.

First, the flowchart of FIG. 6A will be described.
First, in step S201, the first drive control unit 130 uses the first radiation information output from the first computing unit 150 to determine whether or not the radiation 401 has started to be irradiated. To judge. Here, as the radiation start determination, a method of determining that the irradiation of radiation has started when the first radiation information exceeds a predetermined threshold value is preferably used. Then, as a result of the determination in step S201, when the radiation start determination is not performed (S201/NO), the process proceeds to step S202 to perform the blank reading, and then the process returns to step S201.

On the other hand, as a result of the determination in step S201, when the radiation start determination is performed (S201/YES), the process proceeds to step S203.
When the process proceeds to step S203, the second drive control unit 140 uses the second radiation information output by the second calculation unit 160 to perform the radiation start determination that determines that the irradiation of the radiation 401 has started. To judge. Here, as the radiation start determination, a method of determining that the radiation irradiation is started when the second radiation information exceeds a predetermined threshold value is preferably used. The threshold value of the first calculation unit 150 and the threshold value of the second calculation unit 160 are preferably set appropriately from the characteristics of the scintillator layers 313 and 323 of the two-dimensional detectors 111 and 121, respectively. Then, as a result of the determination in step S203, when the radiation start determination is not performed (S203/NO), the process proceeds to step S202 to perform the blank reading, and then the process returns to step S201.

As a result of the determination in step S203, when the radiation start determination is performed (S203/YES), the process proceeds to step S204.
When proceeding to step S204, the third computing unit 170 uses the first current information from the first bias power supply 112 and the second current information from the second bias power supply 122 in steps S201 and S203. It is determined whether or not the radiation start determination is based on a magnetic field other than radiation or external noise such as static electricity. That is, in step S204, the third calculation unit 170 determines whether or not the radiation start determination in steps S201 and S203 is an appropriate determination.

As a result of the determination in step S204, if the radiation start determination is a determination based on external noise (that is, the radiation start determination is not a proper determination) (S204/NO), the process proceeds to step S202, and the third calculation unit 170 For example, through the computer 200, the first drive control unit 130 and the second drive control unit 140 respectively perform a blank reading on the first two-dimensional detector 111 and the second two-dimensional detector 121. Let it be done. After that, the process returns to step S201, and the radiation start determination in steps S201 and S203 is performed again.

On the other hand, as a result of the determination in step S204, if the radiation start determination is not a determination based on external noise (that is, the radiation start determination is a proper determination) (S204/NO), the radiation start determination is radiation irradiation. When it is determined that the start is appropriate, the process proceeds to step S205.
In step S205, it is determined whether the first drive control unit 130 or the second drive control unit 140, or the first drive control unit 130 and the second drive control unit 140 has performed the radiation end determination. to decide.

As a result of the determination in step S205, when the radiation end determination is not performed (S205/NO), the process proceeds to step S206.
In step S206, the first drive control unit 130 and the second drive control unit 140 cause the first two-dimensional detector 111 and the second two-dimensional detector 121 to perform storage, respectively. ..

On the other hand, as a result of the determination in step S205, when the radiation end determination is performed (S205/YES), the process proceeds to step S207.
In step S207, the first drive control unit 130 and the second drive control unit 140 cause the first two-dimensional detector 111 and the second two-dimensional detector 121 to perform the main reading, respectively. .. This main reading is performed in order from the first line to the last line, and when the last line is reached, a series of shooting operations ends, and the process of the flowchart in FIG. 6A ends.

Next, the flowchart of FIG. 6B will be described. The flowchart of FIG. 6(b) is a flowchart showing a modification of FIG. 6(a). In the flowchart of FIG. 6(b), the same step number is assigned to the same processing step as that of FIG. 6(a). is doing.

First, in the process of the flowchart of FIG. 6B, the processes of steps S201 to S204 of FIG. 6A are performed.

Then, as a result of the determination in step S204 of FIG. 6B, when the radiation start determination is determination based on external noise (S204/NO), the process proceeds to step S301.
When the processing proceeds to step S301, for example, the third computing unit 170 moves away from the noise source because the radiation image obtained by the accumulation at step S302 and the main reading at step S303 to be performed after this is an image in which the subject H is not reflected. We warn you of this and encourage you to retake the picture. At this time, for example, the third calculation unit 170 performs a display control related to the warning and the re-imaging on the computer 200, and a sound output control related to the warning and the re-imaging on the computer 200. Can be taken.

When the process of step S301 is completed, or when the radiation start determination is not a determination by external noise in step S204 (S204/YES), the process proceeds to step S302.
In step S302, the first drive control unit 130 and the second drive control unit 140 cause the first two-dimensional detector 111 and the second two-dimensional detector 121 to perform storage, respectively. ..

Subsequently, in step S303, the first drive control unit 130 and the second drive control unit 140 perform the main reading on the first two-dimensional detector 111 and the second two-dimensional detector 121, respectively. Let This main reading is performed in order from the first line to the last line, and when the last line is reached, a series of shooting operations ends, and the processing of the flowchart in FIG. 6B ends.

FIG. 7 shows a control method of the radiation imaging apparatus 100 according to the first embodiment of the present invention, and the first two-dimensional detection by the first drive control unit 130 and the second drive control unit 140 shown in FIG. 6 is a timing chart showing an example of drive timings of the device 111 and the second two-dimensional detector 121.

Until the radiation start determination is performed, the first two-dimensional detector 111 and the second two-dimensional detector 121 control the first drive control unit 130 and the second drive control unit 140, respectively. , The blank reading is repeated. As described above, this blank reading is a drive for sequentially connecting the switch elements 1112 from the first row (0th row) to the last row (Y−1th row), and when the blank reading reaches the last row. Returns to the first line and continues the blank reading. In the example shown in FIG. 7, the switch element 1112 conducts and does not conduct with respect to the first two-dimensional detector 111 and the second two-dimensional detector 121 by the first drive control unit 130 and the second drive control unit 140. The timing of each is the same.

After that, when the radiation start determination is performed, the first two-dimensional detector 111 and the second two-dimensional detector 121 are controlled by the first drive control unit 130 and the second drive control unit 140, respectively. Accumulate repeatedly. As described above, this accumulation is a drive for causing the switch elements 1112 of all the sensor pixels in the first two-dimensional detector 111 and the second two-dimensional detector 121 to be non-conducting and accumulating a signal by radiation. Here, the line for which the radiation start is determined is Ys.

After that, when the radiation end determination is performed, the first two-dimensional detector 111 and the second two-dimensional detector 121 are controlled by the first drive control unit 130 and the second drive control unit 140, respectively. Read the book. As described above, this main reading is performed on the first two-dimensional detector 111 and the second two-dimensional detector 121 in order from the first row to the last row by electrically connecting the switch elements 1112 to charge generated by the accumulation of radiation. This is a drive for reading out a corresponding electric signal. In the case of the example shown in FIG. 7, the second drive control unit 140, based on the information from the first drive control unit 130, simultaneously performs the second reading in the first reading of the first two-dimensional detector 111. The main reading of the container 121 is performed.

FIG. 8 is a timing chart showing a control method of the radiation imaging apparatus 100 according to the first embodiment of the present invention and showing an example of drive timing of each component of the radiation imaging apparatus 100. Specifically, FIG. 8 is an enlarged view of the drive timing in the vicinity of the Ys-th row, which is the row in which the radiation start determination is made by the first two-dimensional detector 111 and the second two-dimensional detector 121.

In FIG. 8, the current when the switch element 1112 of the first two-dimensional detector 111 is conducted is sampled, and this is designated as “S”. Further, the current when the switch element 1112 of the first two-dimensional detector 111 is made non-conductive is sampled, and this is designated as “N”.

Further, in FIG. 8, the current when the switch element 1112 of the second two-dimensional detector 121 is conducted is sampled, and this is designated as “S′”. Further, the current when the switch element 1112 of the second two-dimensional detector 121 is made non-conducting is sampled, and this is designated as “N′”.

Then, the inventor of the present application has found that the current due to the external noise can be removed by performing the arithmetic processing using the above-described S, N, S′, and N′.

Below, first, a method of performing arithmetic processing using S and N which are signals of the first two-dimensional detector 111 will be described. As the calculation process, a process of calculating the difference between S and N is preferably used. In addition, since the current due to external noise fluctuates with the passage of time, it is desirable to use S and N sampled as close as possible. Specifically, if S(y) is the S sampled at the y-th time, N(y) is the N sampled at the y-th time, and X(y) is the radiation information to be output, the following equations (1) to (3) are given. Arithmetic processing as shown in the formula is preferably used.
X(y)=S(y)-N(y) (1)
X(y)=S(y)-N(y-1) (2)
X(y)=S(y)-{N(y)+N(y-1)}/2 (3)

It should be noted that the present embodiment is not limited to the calculation method shown in the equations (1) to (3) described above, and for example, S(y−1) or N(y Alternatively, non-adjacent sample values such as -2) may be used. Further, for example, arbitrary four arithmetic operations, differentiation, and integration may be performed on S(y) and N(y).

In the example described above, the calculation process in the first two-dimensional detector 111 is described, but the calculation process using the signals S′ and N′ of the second two-dimensional detector 121 is also performed in the same manner. ..

Further, it is generally known that when the switch element 1112 is switched between conductive and non-conductive, a current flows through the bias wiring. This is called switching noise. Since the amount of this switching noise varies depending on the row, it may not be removed by the above-described arithmetic processing. Therefore, in the present embodiment, switching noise is removed by storing past current information or radiation information in the storage unit of the radiation imaging apparatus and calculating the current information and the like. It can be said that a mode in which the current information of one frame before in the same row is subtracted is preferable as the calculation for removing the switching noise.

For example, when the first two-dimensional detector 111 has Y rows, S one frame before is S(y−Y), and N one frame before is N(y−Y). Therefore, the arithmetic processing like the following equation (4) is preferably used.
X(y)=[S(y)-{N(y)+N(y-1)}/2]
-[S(y-Y)-{N(y-Y)+N(y-1-Y)}/2] (4)

Then, in this case, as a method of sampling S, a configuration in which A/D conversion is performed a plurality of times during the conduction period of the switch element 1112 and an averaged value thereof is set to S is preferably used. Further, depending on the response speed of the current-voltage conversion circuit 1121, the delay from switching the conduction state of the switch element 1112 to the change of the bias current, which is the current flowing through the bias wiring, may not be negligible. In such a case, a configuration in which the time for starting the sampling of S from the conduction of the switch element 1112 is shifted is preferably used. Further, while the conduction state of the switch element 1112 is switched, the signal of the radiation 401 is not sufficiently output. Therefore, a configuration in which the A/D converted values in such a section are discarded and then averaged is preferably used. The same applies to the method of sampling N.

By the above-described arithmetic processing, the first arithmetic unit 150 and the second arithmetic unit 160 respectively use the current information from the first bias power source 112 and the second bias power source 122 to change the time variation of radiation. The radiation information including is output.

Further, in this embodiment, special attention is required for the timing of A/D conversion of the bias current. Switching noise in the same row is highly reproducible. However, if the sample/hold timing of the A/D converter is not constant, a deviation occurs in the sampling position of the switching noise waveform. Therefore, noise may occur when the calculated value of the difference between S and N between frames is taken. In particular, when the switching noise is larger than the radiation information, even a slight positional deviation leads to a large noise. Therefore, it is desirable that the time between the conduction/non-conduction of the switching element 1112 and the sample/hold timing of the A/D converter be constant. Specifically, it is preferable to use a configuration that generates the timing for switching the conduction/non-conduction of the switch element 1112 and the sample/hold timing of the A/D converter from a common clock.

In FIG. 8, a case where high-frequency external noise such as static electricity is superimposed on the first two-dimensional detector 111 and the second two-dimensional detector 121 will be described. As described above, the current due to external noise fluctuates with the passage of time, so S and N sampled as close as possible are used, but when high-frequency noise of a sampling period or more is entered, it cannot be canceled and remains. There are cases. For example, in the case of static electricity, the static electricity applied to the exterior of the first radiation imaging panel 110 and the second radiation imaging panel 120 is transmitted to the electric substrate via the battery or the like, and the first bias power source 112 and the second bias power source 112 are supplied. A large current/voltage fluctuation can be generated in 122. In this case, even if the first bias power supply 112 and the second bias power supply 122 are mounted as separate circuits, the two bias power supplies 112 and 122 are affected in the same phase because the reference potential of the electric board fluctuates greatly. Can be considered. As a result, it may be determined that the radiation 401 has been exceeded and the radiation 401 has been erroneously emitted. In order to prevent such an erroneous determination, in the present embodiment, in the third arithmetic unit 170, the first current information from the first bias power supply 112 and the second current information from the second bias power supply 122. Is used to perform noise information calculation processing. That is, in the third calculation unit 170, S and S′ sampled at the y-th time are set to S(y) and S′(y), respectively, and N and N′ sampled at the y-th time are set to N(y) and N′, respectively. If'(y)' and the noise information to be output are Z1(y) and Z2(y), arithmetic processing as shown in the following equations (5) to (6) is preferably used.
Z1(y)=S(y)-S'(y) (5)
Z2(y)=N(y)-N'(y) (6)

The temporal order of the noise information obtained by the equations (5) to (6) is... Z1(y-2), Z2(y-2), Z1(y-1), Z2(y- 1), Z1(y), Z2(y), Z1(y+1), Z2(y+1), Z1(y+2), Z2(y+2)... Then, as shown in FIG. 8, the third computing unit 170 cancels external noise that enters in the same phase by taking the difference value between the first current information and the second current information, which are two pieces of current information. can do. Here, it is desirable to set a threshold value in advance for the noise information. If the threshold value is not exceeded, the first drive control unit 130 based on the radiation information from the first calculation unit 150 or the second drive control unit based on the radiation information from the second calculation unit 160. Even if the radiation start determination is made in 140, there is a high possibility that it is an erroneous determination due to noise, so the noise determination is “present”. The threshold value for this noise may be changed depending on the installation environment of the radiation imaging apparatus 100.

As described above, in the radiation imaging apparatus 100 according to the first embodiment, the third calculation unit 170 uses the first current information from the first bias power supply 112 and the second current information from the second bias power supply 122. The current information is used to determine whether the radiation start determination by the first drive control unit 130 and the radiation start determination by the second drive control unit 140 are proper determinations.
With such a configuration, it is possible to suppress erroneous determinations regarding the start of radiation irradiation.

(Second embodiment)
Next, a second embodiment of the present invention will be described. In the following description of the second embodiment, items common to the above-described first embodiment will be omitted, and items different from the above-described first embodiment will be described.

The schematic configuration of the radiation imaging system according to the second embodiment is similar to the schematic configuration of the radiation imaging system 10 according to the first embodiment shown in FIG. Therefore, the schematic configuration of the radiation imaging apparatus according to the second embodiment is similar to the schematic configuration of the radiation imaging apparatus 100 according to the first embodiment shown in FIG.

FIG. 9 shows a control method of the radiation imaging apparatus 100 according to the second embodiment of the present invention, and the first two-dimensional detection by the first drive control unit 130 and the second drive control unit 140 shown in FIG. 6 is a timing chart showing an example of drive timings of the device 111 and the second two-dimensional detector 121.

Similar to the first embodiment shown in FIG. 7, in FIG. 9 as well, the first two-dimensional detector 111 and the second two-dimensional detector 121 are respectively operated until the radiation start determination is performed. , Under the control of the first drive control unit 130 and the second drive control unit 140, idle reading is repeated. As described above, this blank reading is a drive for sequentially connecting the switch elements 1112 from the first row (0th row) to the last row (Y−1th row), and when the blank reading reaches the last row. Returns to the first line and continues the blank reading. The drive timing in the second embodiment shown in FIG. 9 differs from the drive timing in the first embodiment shown in FIG. 7 in that the conduction timing of the switch element 1112 of the second two-dimensional detector 121 is the first. The timing is different from the conduction timing of the switch element 1112 of the two-dimensional detector 111 and is driven so as to match the non-conduction timing. Regarding the conduction timing of the switch element 1112 of the second two-dimensional detector 121, the conduction timing of the switch element 1112 is delayed by a time which is half of one row of the first two-dimensional detector 111. The operations of accumulation and main reading after the idle reading are the same as those in the first embodiment.

FIG. 10 is a timing chart showing a control method of the radiation imaging apparatus 100 according to the second exemplary embodiment of the present invention and showing an example of drive timing of each component of the radiation imaging apparatus 100. This FIG. 10 corresponds to the timing chart in the first embodiment shown in FIG.

As described in FIG. 9, when the drive timing of the switch element 1112 is deviated by half a row in the first two-dimensional detector 111 and the second two-dimensional detector 121 as in this embodiment, the first The sampling timings of S and N which are the signals of the two-dimensional detector 111 and S′ and N′ which are the signals of the second two-dimensional detector 121 are also shifted by half a row.

The calculation method in the case where the radiation start determination is performed based on the current information output from the first bias power supply 112 and the second bias power supply 122 is the same as in the above-described first embodiment. Further, in the present embodiment, for the calculation of the noise information of the third calculation unit 170, the calculation processing as expressed by the following expressions (5) to (6) is preferably used.
Z1(y)=S(y)-N'(y) (7)
Z2(y)=S'(y)-N(y) (8)

Noise components are canceled in Z1 and Z2, and switching noise and radiation information appear. Regarding the radiation information that can be acquired when the switch element 1112 is turned on, in the first embodiment shown in FIG. 8, it is only for half a row, but in the second embodiment shown in FIG. 10, it can be acquired seamlessly in time. . Further, in the first embodiment, since the calculated value of the difference between the radiation information in the first two-dimensional detector 111 and the radiation information in the second two-dimensional detector 121 is taken, the radiation component is reduced. In the second embodiment, since there is a time lag, there is no reduction. However, as shown in FIG. 10, since switching noise remains, it is desirable to adopt a method of canceling by calculating the difference calculation value with the information of one frame before for Z1 and Z2.

(Third Embodiment)
Next, a third embodiment of the present invention will be described. In the description of the third embodiment described below, description of items common to the above-described first embodiment and second embodiment will be omitted, and the above-described first embodiment and second embodiment will be omitted. Matters different from the embodiment will be described.

The schematic configuration of the radiation imaging system according to the third exemplary embodiment is similar to the schematic configuration of the radiation imaging system 10 according to the first exemplary embodiment shown in FIG. Therefore, the schematic configuration of the radiation imaging apparatus according to the third embodiment is similar to the schematic configuration of the radiation imaging apparatus 100 according to the first embodiment shown in FIG.

FIG. 11 shows a control method of the radiation imaging apparatus 100 according to the third embodiment of the present invention, and the first two-dimensional detection by the first drive control unit 130 and the second drive control unit 140 shown in FIG. 6 is a timing chart showing an example of drive timings of the device 111 and the second two-dimensional detector 121.

Similar to the first embodiment shown in FIG. 7 and the second embodiment shown in FIG. 9, in FIG. 11 as well, the first two-dimensional detector 111 is Under the control of the drive control unit 130 of No. 1, the blank reading is repeated. As described above, this blank reading is a drive for sequentially connecting the switch elements 1112 from the first row (0th row) to the last row (Y−1th row), and when the blank reading reaches the last row. Returns to the first line and continues the blank reading. The drive timing in the third embodiment shown in FIG. 11 differs from the drive timing in the first embodiment shown in FIG. 7 in that the second two-dimensional detector 121 is provided until the radiation start determination is performed. The point is that, under the control of the second drive control unit 140, all the switch elements 1112 are driven to be non-conducting, that is, are in a storage state. Further, the timing at which the first drive control unit 130 starts the main reading and the timing at which the second drive control unit 140 starts the main reading are the same as in the above-described first and second embodiments.

FIG. 12 is a timing chart showing a control method of the radiation imaging apparatus 100 according to the third exemplary embodiment of the present invention and showing an example of drive timing of each component of the radiation imaging apparatus 100. 12 corresponds to the timing chart in the first embodiment shown in FIG. 8 and the second embodiment shown in FIG.

As described with reference to FIG. 11, in the present embodiment, the switch element 1112 of the second two-dimensional detector 121 is non-conductive until the start of radiation determination is performed, so that the signal component is only N′. Therefore, the calculation method in the case of performing the radiation start determination is a form in which the information regarding the first two-dimensional detector 111 is used according to the flowchart shown in FIG. For the determination, it is possible to make a determination using the information related to the second two-dimensional detector 121. Since the second two-dimensional detector 121 has no radiation information, it can detect only the noise superimposed on the corresponding bias power supply. When the radiation start determination is performed using the information related to the first two-dimensional detector 111, the second calculation unit 160 determines whether or not the predetermined threshold is exceeded, and if it is exceeded, it may be noise. It is highly likely. In that case, as shown in FIG. 6A and FIG. 6B, it is possible to continue idle reading or issue a warning.

In the third embodiment, since the second two-dimensional detector 121 does not perform the blank reading, the dark current component of the second two-dimensional detector 121 may be accumulated and may be superimposed on the main-read image. When the energy subtraction image is unnecessary, the image of the second two-dimensional detector 121 is unnecessary and the main reading is not performed. When the image of the second two-dimensional detector 121 is required, the dark current image of the second two-dimensional detector 121 is stored in the computer 200 or the like in advance, and the dark current image is subtracted from the radiation image. It is possible to take a method such as doing.

(Other embodiments)
The present invention supplies a program that implements one or more functions of the above-described embodiments to a system or apparatus via a network or a storage medium, and one or more processors in a computer of the system or apparatus read and execute the program. It can also be realized by the processing. It can also be realized by a circuit (for example, ASIC) that realizes one or more functions.
The program and a computer-readable storage medium storing the program are included in the present invention.

It should be noted that the above-described embodiments of the present invention are merely examples of embodying the present invention, and the technical scope of the present invention should not be limitedly interpreted by these. Is. That is, the present invention can be implemented in various forms without departing from the technical idea or the main features thereof.

10: radiation imaging system, 100: radiation imaging apparatus, 110: first radiation imaging panel, 111: first two-dimensional detector, 112: first bias power supply, 120: second radiation imaging panel, 121: 2nd two-dimensional detector, 122: 2nd bias power supply, 130: 1st drive control unit, 140: 2nd drive control unit, 150: 1st calculating part, 160: 2nd calculating part, 170: Third computing unit, 200: Computer, 300: Radiation control device, 400: Radiation generator, 401: Radiation, T: Inspection target

Claims (13)

A first two-dimensional detector that detects radiation and outputs first image information;
A second two-dimensional detector that detects the radiation transmitted through the first two-dimensional detector and outputs second image information;
A first bias power supply which supplies a bias voltage to the first two-dimensional detector through a bias wiring and outputs first current information including a time variation of a current flowing through the bias wiring;
A second bias power supply which supplies a bias voltage to the second two-dimensional detector through a bias wiring and outputs second current information including time variation of a current flowing through the bias wiring;
First computing means for computing the first current information and outputting first radiation information including time variation of the intensity of the radiation;
Second arithmetic means for arithmetically processing the second current information to output second radiation information including time variation of the intensity of the radiation;
First drive control means for determining the start of irradiation of the radiation using the first radiation information and controlling the driving of the first two-dimensional detector;
Second drive control means for determining the start of irradiation of the radiation by using the second radiation information and controlling the drive of the second two-dimensional detector;
Whether the start determination by the first drive control means and the start determination by the second drive control means are proper determinations by arithmetically processing the first current information and the second current information. A third calculation means for determining
A radiation imaging apparatus comprising: When the third calculation means determines that the determination is not appropriate, the start determination by the first drive control means and the start determination by the second drive control means are performed again. The radiation imaging apparatus according to claim 1. The radiation imaging apparatus according to claim 1, wherein a warning is given when the third calculation unit determines that the determination is not appropriate. Included in the second two-dimensional detector included in the first two-dimensional detector, the drive timing of the switch element included in the first two-dimensional detector included in the first and two-dimensional detectors. The radiation imaging apparatus according to any one of claims 1 to 3, wherein the drive timings for switching the switch element on and off are the same timing. Included in the second two-dimensional detector included in the first two-dimensional detector, the drive timing of the switch element included in the first two-dimensional detector included in the first and two-dimensional detectors. 4. The radiation imaging apparatus according to claim 1, wherein the drive timings for switching the switch element on and off are different from each other. The first drive control means performs the start determination and shifts the drive of the first two-dimensional detector to accumulation when the first radiation information exceeds a threshold value,
The second drive control means makes the start determination and shifts the drive of the second two-dimensional detector to accumulation when the second radiation information exceeds a threshold value. The radiation imaging apparatus according to any one of 1 to 5. 7. The first bias power source and the second bias power source are configured to include a current-voltage conversion circuit configured to include a resistor and an operational amplifier, and the first bias power source and the second bias power source are configured to include a current-voltage conversion circuit. The radiation imaging apparatus according to the paragraph. When the first arithmetic means is S, the current information when the switch element included in the first two-dimensional detector is conductive is S, and the current information when the switch element is non-conductive is N, The radiation imaging apparatus according to claim 1, wherein the first radiation information is acquired using a calculated value of a difference between the S and the N. 9. The radiation imaging apparatus according to claim 8, wherein A/D conversion is performed a plurality of times during the conduction period of the switch element, and a value obtained by averaging them is set as the S. 10. The radiation imaging apparatus according to claim 8, wherein the first calculation unit acquires the first radiation information by using the S of one frame before and the N of one frame before. apparatus. The radiation imaging apparatus according to any one of claims 8 to 10, wherein the calculated values of the S and the N are further integrated, and the start determination is performed based on a threshold value for a plurality of integration intervals. The radiation imaging apparatus according to any one of claims 8 to 11, wherein the switch elements are electrically connected every other row. A first two-dimensional detector that detects radiation and outputs first image information, and a second two-dimensional detector that detects the radiation that has passed through the first two-dimensional detector and outputs second image information. A two-dimensional detector; a first bias power supply which supplies a bias voltage to the first two-dimensional detector through a bias wiring and outputs first current information including a time variation of a current flowing through the bias wiring; A second bias power supply which supplies a bias voltage to the second two-dimensional detector through a bias wiring and outputs second current information including time variation of a current flowing through the bias wiring. A control method,
A first calculation step of processing the first current information to output first radiation information including time variation of the intensity of the radiation;
A second calculation step of processing the second current information to output second radiation information including a temporal variation of the intensity of the radiation;
A first drive control step of determining the start of irradiation of the radiation using the first radiation information and controlling the drive of the first two-dimensional detector;
A second drive control step of determining the start of irradiation of the radiation using the second radiation information and controlling the drive of the second two-dimensional detector;
Whether the start determination by the first drive control step and the start determination by the second drive control step are proper determinations by arithmetically processing the first current information and the second current information. A third calculation step for determining
A method for controlling a radiation imaging apparatus, comprising:

Images