Radiation imaging device, radiation imaging system, radiation imaging method, and program

Abstract

To provide a technique advantageous for reducing the occurrence of artifacts.SOLUTION: A radiation imaging device comprises: a detection unit in which a plurality of pixels are arranged in a matrix, the plurality of pixels including composite pixels each composed of a main pixel and a sub pixel configured as one pixel, the main pixel and the sub pixel being capable of accumulating charges corresponding to a radiation dose and reading out the charges separately; a driving unit to which a plurality of driving lines are connected, the plurality of driving lines being configured to drive the plurality of pixels in a row unit into either a non-conductive state or a conductive state; and a control unit which controls the driving unit to output signals based on charges from the pixels driven in the row unit. The control unit controls the driving unit such that timings at which the main pixel and the sub pixel are set into the conductive state are different, and such that a timing at which one of the main pixel and the sub pixel is changed from the conductive state to the non-conductive state overlaps with a timing at which the other is changed from the non-conductive state to the conductive state.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The disclosed technology relates to a radiation imaging apparatus, a radiation imaging system, a radiation imaging method, and a program, and more particularly to a radiation imaging apparatus, a radiation imaging system, a radiation imaging method, and a program suitable for use in medical diagnosis and industrial non-destructive testing. [Background technology]

[0002] In recent years, radiation imaging devices using flat panel detectors (hereinafter referred to as FPDs) made of semiconductor materials have begun to be put into practical use as imaging devices used in X-ray medical image diagnosis and non-destructive testing. Radiation imaging devices using FPDs are capable of digital imaging by converting radiation such as X-rays that have passed through a subject such as a patient into analog electrical signals, which are then converted into analog-to-digital signals to obtain digital image signals. FPDs used in radiation imaging devices are broadly divided into direct conversion types and indirect conversion types.

[0003] A direct conversion type radiation imaging device is a device that has an FPD in which a plurality of pixels, each including a conversion element made of a semiconductor material such as a-Se that can directly convert radiation into electric charges, are arranged two-dimensionally. An indirect conversion type radiation imaging device is a device that has an FPD in which a plurality of pixels, each including a conversion element, each including a wavelength converter such as a phosphor that can convert radiation into light and a photoelectric conversion element made of a semiconductor material such as a-Si that can convert light into electric charges, are arranged two-dimensionally. Radiation imaging devices that have such FPDs are used, for example, in medical image diagnosis as digital imaging devices for capturing still images such as general imaging and for capturing moving images such as fluoroscopic imaging.

[0004] An automatic exposure control device that uses this FPD to automatically control X-rays to an appropriate exposure amount is disclosed in, for example, Patent Document 1. In the automatic exposure control device disclosed in Patent Document 1, when X-ray irradiation begins, the X-rays that have passed through the subject are converted into optical signals, and these optical signals are then converted into electrical signals. Some pixels are divided into main pixels and sub-pixels as composite pixels, with the main pixels being the pixels for outputting image signals and the sub-pixels being the pixels for detecting X-ray exposure amount, and the electrical signals of the sub-pixels are read out at predetermined time intervals, and the appropriate exposure amount is determined by utilizing the fact that this electrical signal is proportional to the intensity of the X-rays, thereby performing automatic exposure amount control. [Prior art documents] [Patent documents]

[0005] [Patent Document 1] Patent No. 5775812 specification Summary of the Invention [Problem to be solved by the invention]

[0006] An automatic exposure control device that uses an FPD to automatically control X-rays to an appropriate exposure dose arbitrarily reads out electrical signals accumulated in pixels within a region of interest, sequentially determines the exposure dose, stops X-ray irradiation at a predetermined exposure dose, and reads out signals from all pixels as image data. In Patent Document 1, to read out composite pixels in the same way as normal pixels, the switch elements of the main pixel and sub-pixel are turned on simultaneously and added in an analog manner to read out electrical signals.

[0007] FPD switching elements typically use a potential difference of 10 to 20 V to switch the switching element ON and OFF. Switching the switching element from ON to OFF and from OFF to ON generates unintended charges (gate injection) in the signal lines via the capacitive coupling formed within the switching element and pixel. The gate injection from ON to OFF and the gate injection from OFF to ON reverse the sign of the charge, so in the case of "OFF → ON → OFF → readout," the gate injections essentially cancel each other out during readout, having almost no effect on the photoelectrically converted charge. Furthermore, similar effects are superimposed on adjacent pixels, so there is almost no artifact-like effect on the overall image.

[0008] In Patent Document 1, a normal pixel has one switch element, and a composite pixel has two switch elements, one for the main pixel and one for the sub-pixel, so the injection for the composite pixel is twice that of a normal pixel. In this case, for example, the initial injection from OFF to ON may exceed the rating of the readout circuit, activating the protection circuit, and the gate injection cannot be canceled when ON is changed to OFF, making it impossible to read out the photoelectrically converted charge normally. Also, for example, the influence of the gate injection differs between adjacent pixels, so the difference in pixel value between the composite pixel and the normal pixel becomes noticeable, resulting in problems such as artifacts in the image.

[0009] In view of the above, the disclosed technology has an object to provide a technology that is advantageous in reducing the occurrence of artifacts. [Means for solving the problem]

[0010] A radiation imaging device according to one aspect of the disclosed technology includes a detection unit in which a plurality of pixels are arranged in a matrix, including composite pixels each of which is configured as a main pixel and a sub-pixel that accumulate electric charges corresponding to a radiation dose and are capable of separately reading out the electric charges; a drive unit connected to a plurality of drive wirings that drives the plurality of pixels row by row into a non-conductive state or a conductive state; a control unit that controls the drive unit and causes the pixels driven row by row to output signals based on the charges, The control unit controlling the driving unit so that the main pixel and the sub-pixel are brought into the conductive state at different timings; The driving unit controls the driving unit so that the timing at which one of the main pixel and the sub-pixel is changed from the conductive state to the non-conductive state coincides with the timing at which the other of the main pixel and the sub-pixel is changed from the non-conductive state to the conductive state. [Effects of the Invention]

[0011] The disclosed technology can provide a technology that is advantageous in reducing the occurrence of artifacts. [Brief explanation of the drawings]

[0012] [Figure 1] FIG. 1 is a block diagram of a radiation imaging system according to first to third embodiments. [Figure 2] FIG. 2 is a diagram showing an equivalent circuit of the two-dimensional detector according to the first to third embodiments. [Figure 3] FIG. 2 is a flowchart for explaining the processing flow of the radiation imaging system according to the first embodiment. [Figure 4] FIG. 2 is a diagram showing the operation timing of the two-dimensional detector according to the first embodiment. [Figure 5] FIG. 10 is a flowchart for explaining the processing flow of the radiation imaging system according to the second embodiment. [Figure 6] FIG. 10 is a diagram showing the operation timing of the two-dimensional detector according to the second embodiment. [Figure 7] FIG. 10 is a diagram showing the operation timing of the two-dimensional detector according to the second embodiment. [Figure 8] FIG. 10 is a flowchart for explaining the processing flow of the radiation imaging system according to the third embodiment. [Figure 9] FIG. 11 is a diagram showing the operation timing of the two-dimensional detector according to the third embodiment. DETAILED DESCRIPTION OF THE INVENTION

[0013] Hereinafter, embodiments will be described in detail with reference to the accompanying drawings. Note that the following embodiments do not limit the scope of the invention claimed. Although multiple features are described in the embodiments, not all of these multiple features are necessarily essential to the invention, and multiple features may be combined arbitrarily. Furthermore, in the accompanying drawings, the same reference numerals are used to designate the same or similar components, and redundant explanations will be omitted.

[0014] The radiation in the disclosed technology includes α-rays, β-rays, γ-rays, etc., which are beams created by particles (including photons) emitted by radioactive decay, as well as beams having the same or higher energy levels, such as X-rays, particle beams, and cosmic rays.

[0015] (First embodiment) 1 is a block diagram of a radiation imaging system 100 according to the first embodiment. The radiation imaging system 100 of this embodiment is composed of an X-ray generator 12, an X-ray control device 10, a control computer 20, and an X-ray imaging device 30.

[0016] The X-ray control device 10 controls the emission of X-rays by the X-ray generation device 12. The control computer 20 acquires image information and controls the X-ray imaging device 30. The control computer 20 performs overall control of the radiation imaging system 100. The control computer 20 can also function as a user interface when a user (such as a radiologist) captures a radiation image using the radiation imaging system 100. For example, the user inputs radiation image capture conditions and the like to the control computer 20, and the control computer 20 controls the X-ray imaging device 30 and the X-ray generation device 12 according to the input imaging conditions. The control computer 20 may also include a signal processing unit that processes signals for generating a radiation image output from the X-ray imaging device 30. The control computer 20 processes signals for generating a radiation image output from the X-ray imaging device 30, and displays the radiation image captured by the X-ray imaging device 30 on a display unit included in the control computer 20 or an external display.

[0017] The X-ray imaging device 30 comprises a two-dimensional detector 112 that detects X-rays, an arithmetic unit 34 that calculates charge information from the two-dimensional detector 112 and outputs exposure information, and a drive control unit 36 that controls the drive of the two-dimensional detector 112 and the X-ray irradiation based on the exposure information.

[0018] The two-dimensional detector 112 of the X-ray imaging device 30 is a sensor in which elements that detect X-rays are arranged in an array of X columns and Y rows, and detects X-rays and outputs charge information and image information during irradiation. The arithmetic unit 34 calculates the charge information during irradiation output from the two-dimensional detector 112 and outputs exposure information including time fluctuations in X-ray intensity to the drive control unit 36. A digital signal processing circuit such as an FPGA, DSP, or processor is preferably used as the arithmetic unit 34. The arithmetic unit 34 may also be configured using analog circuits such as a sample-and-hold circuit and an operational amplifier. Although the arithmetic unit 34 is included in the X-ray imaging device 30 in FIG. 1, it may also be included in the control computer 20.

[0019] The drive control unit 36 controls the two-dimensional detector 112 using the drive method requested by the control computer 20. The drive control unit 36 (controller) controls the drive circuit 114 (driver) based on the drive method requested by the control computer 20, and performs control to output signals based on charges from pixels driven row by row. The drive control unit 36 (controller) also controls the drive circuit 114 (driver) using exposure information output by the arithmetic unit 34, and changes the drive method of the two-dimensional detector 112.

[0020] FIG. 2 shows an equivalent circuit diagram of the two-dimensional detector 112 according to the first embodiment. For ease of explanation, FIG. 2 shows an FPD having 6 rows and 6 columns of pixels as the pixel array. However, the two-dimensional detector 112 of an actual X-ray imaging device 30 has a larger number of pixels; for example, the two-dimensional detector 112 of a 17-inch X-ray imaging device has approximately 3,500 rows and 3,500 columns of pixels. The two-dimensional detector 112 (detection unit) has a plurality of pixels arranged in a matrix, including composite pixels, each of which is configured as a main pixel and a sub-pixel that can accumulate a charge corresponding to the radiation dose and read out the charge separately. The plurality of pixels arranged in the two-dimensional detector 112 (detection unit) may include composite pixels and normal pixels that are not configured as composite pixels.

[0021] The two-dimensional detector 112 (detection unit) has a plurality of pixels arranged in a matrix. Each pixel has a conversion element 102 that converts radiation or light into an electric charge and a switch element 101 that outputs an electrical signal corresponding to the electric charge. In this embodiment, a metal-insulator-semiconductor (MIS) photodiode, primarily made of amorphous silicon and disposed on an insulating substrate such as a glass substrate, is used as the photoelectric conversion element that converts light irradiated onto the conversion element into an electric charge. However, a pin-type photodiode may also be used. Furthermore, the conversion element may preferably be an indirect conversion element that includes a wavelength converter on the radiation incident side of the photoelectric conversion element that converts radiation into light in a wavelength range detectable by the photoelectric conversion element, or a direct conversion element that directly converts radiation into an electric charge. A transistor having a control terminal and two main terminals is preferably used as the switch element 101; in this embodiment, a thin-film transistor (TFT) is used. One electrode of the conversion element 102 is electrically connected to one of the two main terminals of the switch element 101, and the other electrode is electrically connected to a bias power supply 103 via a common bias wiring Bs.

[0022] A plurality of drive wirings (G1 to G6) that drive a plurality of pixels in row units to a non-conductive or conductive state are connected to the drive circuit 114 (drive unit). The control terminals of the plurality of switch elements 101 in the row direction, for example, T11 to T61, are electrically connected in common to the drive wiring G1 (row signal line) of the first row, and a drive signal Vg1 that controls the conductive state of the switch elements 101 is supplied from the drive circuit 114 to each row via the drive wiring G1. The other main terminals of the plurality of switch elements 101 in the column direction, for example, T11 to T16, are electrically connected to the signal wiring Sig1 (column signal line) of the first column. While the switch element 101 is in a conductive state, the switch element 101 outputs an electrical signal corresponding to the charge of the conversion element 102 to the readout circuit 113 via the signal wiring Sig1. The signal wirings Sig1 to Sig6 arranged in the column direction transmit the electrical signals output from the plurality of pixels to the readout circuit 113.

[0023] The main pixel includes a main conversion element that converts radiation into electric charges and a main switching element that outputs a signal corresponding to the electric charges converted by the main conversion element. The sub-pixel includes a sub-conversion element that converts radiation into electric charges and a sub-switching element that outputs a signal corresponding to the electric charges converted by the sub-conversion element. Among the multiple drive wirings, the main drive wiring to which the main switching element is connected is different from the sub-drive wiring to which the sub-switching element is connected. Of the conversion elements 102, S22, S25, S52, and S55 are formed as conversion elements (main conversion elements) of a composite pixel, and are each connected to a bias wiring Bs and a switch element (main switching element).

[0024] A composite pixel will be described using S22 as an example. The conversion element S22 in the composite pixel is divided into a conversion element S22a (main conversion element) of the main pixel and a conversion element S22b (sub-conversion element) of the sub-pixel, and S22a and S22b are connected to a signal wiring Sig2 via switch elements T22a (main switch element) and T22b (sub-switch element), respectively. A drive signal Vg2 is applied to the switch element T22a (main conversion element) via a drive wiring G2 (main drive wiring), and a drive signal Vg2b is applied to the switch element T22b via a drive wiring G2b (sub-drive wiring). The main drive wiring is connected to a main switch element (e.g., T22a) and a switch element of a normal pixel that is not configured as a composite pixel. Furthermore, a sub-switch element of the sub-pixel (e.g., T22b) is connected to the sub-drive wiring. That is, the conduction states of the conversion element S12 of the pixel for outputting the image signal (normal pixel), the conversion element S22a of the main pixel, the conversion elements S32 and S42 of the normal pixel, the conversion element S52a of the main pixel, and the conversion element S62 of the normal pixel are controlled by the drive signal Vg2, and an electrical signal according to the charge of each conversion element is transmitted from the signal wirings Sig1 to Sig6 to the readout circuit 113.

[0025] The conduction state of the conversion elements S22b and S52b of the subpixels is independently controlled by a drive signal Vg2b, and an electrical signal corresponding to the charge of each conversion element is transmitted to the readout circuit 113 via the signal wirings Sig2 and Sig5. The same applies to the conversion elements S25b and S55b of the subpixels in other composite pixels. The drive circuit 114 (drive unit) supplies a drive signal to a sub-drive wiring (e.g., G2b) under the control of the drive control unit 36, thereby driving the subpixels independently of the main pixel and normal pixel. That is, the drive signal Vg2b on the drive wiring G2b and the drive signal Vg5b on the drive wiring G5b are wired to control the switch elements of only the subpixels, and transmit an electrical signal corresponding to the charge of the conversion element of each subpixel to the readout circuit 113. This is because the subpixels are used as pixels for automatic exposure control, and the normal pixel and main pixel are used as pixels for image data. A detailed control method will be described later.

[0026] FIG. 2 shows an example in which S22, S25, S52, and S55 are used as a composite pixel, but the present invention is not limited to this example. A composite pixel may be created by shifting the signal wiring or adding a gate line (drive wiring), or these may be combined to arrange the composite pixel unevenly.

[0027] The readout circuit 113 is provided with amplifier circuits 106 for amplifying the electrical signals output in parallel from the two-dimensional detector 112 (detection unit) corresponding to each signal wiring. Each amplifier circuit 106 includes an integral amplifier 105 (integral amplifier) that amplifies the output electrical signal, a variable amplifier 104 (variable gain amplifier) that amplifies the electrical signal from the integral amplifier 105, a sample-and-hold circuit 107 that samples and holds the amplified electrical signal, and a buffer amplifier 109.

[0028] The integrating amplifier 105 includes an operational amplifier that amplifies and outputs the electrical signal read from each pixel, an integral capacitor, and a reset switch. The integrating amplifier 105 can change its amplification factor by changing the value of the integral capacitor. The electrical signal output from the pixel is input to the inverting input terminal of the operational amplifier, a reference voltage Vref is input from a reference power supply 111 to the non-inverting input terminal, and the amplified electrical signal is output from the output terminal. In addition, an integral capacitor is disposed between the inverting input terminal and output terminal of the operational amplifier.

[0029] The sample-and-hold circuits 107 are provided corresponding to the respective amplifier circuits 106, and are composed of sampling switches and sampling capacitors. The readout circuit 113 also has a multiplexer 108 that sequentially outputs the electrical signals read out in parallel from the respective amplifier circuits 106 as serial image signals, and a buffer amplifier 109 that performs impedance conversion on the image signals and outputs them.

[0030] The image signal Vout, which is an analog electrical signal output from the buffer amplifier 109, is converted into digital data by the A / D converter 110. The digital data (charge information) during X-ray irradiation is output to the arithmetic unit 34 shown in Fig. 1 and can be used for automatic exposure control, etc. Furthermore, the digital data (image information) after X-ray irradiation is output to the control computer 20 shown in Fig. 1, and the control computer 20 can process the acquired digital data to generate an X-ray image.

[0031] The power supply unit (not shown) includes a reference power supply 111 for the amplifier circuit 106 and a bias power supply 103. The reference power supply 111 supplies a reference voltage Vref to the non-inverting input terminal of each operational amplifier. The bias power supply 103 supplies a bias voltage Vs in common to the other electrode of each conversion element via a bias line Bs.

[0032] 1, the drive circuit 114 outputs to each drive wiring a drive signal having a conductive voltage Von that turns the switch element 101 into a conductive state and a non-conductive voltage Voff that turns the switch element 101 into a non-conductive state. In this way, the drive circuit 114 controls the conductive state and non-conductive state of the switch element 101, and drives the two-dimensional detector 112 (detection unit).

[0033] The control signal CPV is a shift clock for the shift register used in the drive circuit 114. The control signal DIO is a signal for causing the shift register to start shifting in accordance with the shift clock. The control signal OE is a signal for controlling the output terminal of the shift register. Using the above control signals CPV, DIO, and OE, the drive control unit 36 sets the time required for the drive circuit 114 to drive the two-dimensional detector 112 (detection unit) and the scanning direction.

[0034] The drive control unit 36 also controls the operation of each component of the readout circuit 113 by providing a control signal RC, a control signal SH, and a control signal CLK to the readout circuit 113. Here, the control signal RC is a signal that controls the operation of the reset switch of the integrating amplifier, the control signal SH is a signal that controls the operation of the sample-and-hold circuit 107, and the control signal CLK is a signal that controls the operation of the multiplexer 108.

[0035] Fig. 3 is a flowchart illustrating the processing flow of the radiation imaging system 100 according to the first embodiment. Fig. 4 is a timing chart of the drive circuit 114 according to the first embodiment. Imaging drive for automatic exposure amount control in the radiation imaging system 100 according to the first embodiment will be described using Figs. 3 and 4.

[0036] First, in S301, when the user completes preparations for imaging, such as setting conditions for capturing a radiographic image, the process proceeds to S302. In S302, the drive control unit 36 starts pre-reading. Here, pre-reading is a reset operation in which the switch element 101 of each pixel of the two-dimensional detector 112 (detection unit) repeatedly turns ON / OFF to reset the dark current of the pixel. The drive control unit 36 inputs a control signal DIO to the drive circuit 114 on a frame-by-frame basis, and inputs control signals CPV and OE on a gate line (drive wiring) basis to perform sequential scanning. Here, as shown in FIG. 4, drive signals Vg1-2, 2b, 3-5, 5b, and 6 are applied to the drive wirings G1-2, 2b, 3-5, 5b, and 6 connected to the drive circuit 114 of the two-dimensional detector 112 in that order, resetting the dark current. Depending on the configuration of the drive circuit 114, drive signals Vg1-6, V2b, and V5b may be applied to apply an ON voltage to the drive wirings G1-6, G2b, and G5b in that order so that the normal pixels and main pixels are scanned first, and then the sub-pixels are scanned. As shown in Fig. 4, when resetting the dark current of a plurality of pixels before irradiation with radiation, the drive control unit 36 (controller) controls the drive circuit 114 (driver) so that the timing at which one of the main pixels and the sub-pixels is changed from a conductive state to a non-conductive state does not overlap with the timing at which the other is changed from a non-conductive state to a conductive state.

[0037] Next, in S303, the drive control unit 36 of the X-ray imaging device 30 determines whether X-ray irradiation has started. When the user issues an instruction to start radiation irradiation, such as by pressing an exposure switch (S303-YES), the X-ray imaging device 30 proceeds to S304. In S304, when irradiation control is performed and X-rays are irradiated, the drive control unit 36 sequentially applies drive signals Vg2b and Vg5b to the sub-pixels S22b, S52b, S25b, and S55b for automatic exposure control, thereby sequentially reading out electrical signals corresponding to the charges of the conversion elements of each sub-pixel. The X-ray imaging device 30 then repeats the readout operation.

[0038] As shown in FIG. 4, when automatic exposure control (AEC) is performed during radiation irradiation, the drive control unit 36 (controller) controls the drive circuit 114 (driver) to turn on the subpixels and turn off the main and normal pixels. Charge information a and b shown in FIG. 4 indicate charge information read out by the readout circuit 113. Charge information a indicates charge information read out via signal wirings Sig1, Sig3, Sig4, and Sig6 to which no composite pixel is connected, and charge information b indicates charge information read out via signal wirings Sig2 and Sig5 to which the composite pixel is connected. The readout circuit 113 reads out charge information b of the subpixels of composite pixels whose switch elements are turned on (ON) and adds up the charge information pixel by pixel (NO in S305). When the added charge information b reaches a predetermined threshold (YES in S305), the process proceeds to S306. The drive control unit 36 outputs a signal to stop the radiation irradiation when the charge information obtained by adding the signal based on the charge read from the sub-pixel reaches a threshold value (S306). That is, the drive control unit 36 transmits an irradiation stop signal to the X-ray control device 10 to control the irradiation stop. In response to the irradiation stop signal, the X-ray control device 10 stops the X-ray irradiation from the X-ray generator 12. During this time, an OFF voltage that turns off the switch elements continues to be applied to the normal pixels and main pixels for image data, and charge accumulation occurs, and charge information a is not output. Note that the drive control unit 36 can determine whether or not the subject is moving during radiation irradiation based on changes in the signal based on the charge read from the sub-pixel. This determination result may be displayed on a display or the like to notify the user when reimaging is necessary.

[0039] Next, when the X-ray irradiation is stopped, in S307, the drive control unit 36 performs the main reading operation. The main reading operation is an operation in which the drive circuit 114 sequentially applies a conduction voltage (TFTON voltage) that turns on the switch element 101 to the drive wirings G1-2, 2b, 3-5, 5b, and 6, and reads out the charges accumulated during the X-ray irradiation from the conversion elements 102 connected to each gate line (drive wiring) to the readout circuit 113. The charges are then converted into digital data and transferred to a computer as image information. The signals read out by the readout circuit 113 are converted into digital data and transferred to the control computer 20 as image information. The control computer 20 generates an X-ray image from the acquired image information and displays it on a display or the like.

[0040] In FIG. 4, a conduction voltage (TFTON) is applied to the drive wirings G1-2, 2b, 3-5, 5b, and 6 connected to the drive circuit 114 of the two-dimensional detector 112 in this order. Here, drive signals Vg1, Vg3, Vg4, and Vg6 for applying the conduction voltage (TFTON) are applied for a fixed time N to the gate lines (drive wirings G1, G3, G4, and G6) to which only normal pixels are connected. Drive signals Vg2 and Vg5 for applying the conduction voltage (TFTON) are applied for a fixed time Na to the gate lines (drive wirings G2 and G5) to which normal pixels and main pixels are connected. Furthermore, drive signals Vg2b and Vg5b for applying the conduction voltage (TFTON) are applied for a fixed time Nb to the gate lines (drive wirings G2b and G5b) to which subpixels are connected. The drive control unit 36 can control the timing of applying a conduction voltage (TFTON) to the drive wirings. When the drive signal Vg2 is turned OFF on the drive wiring G2, the drive signal Vg2b on the drive wiring G2b is controlled to be ON. Similarly, when the drive signal Vg5 is turned OFF on the drive wiring G5, the drive signal Vg5b on the drive wiring G5b is controlled to be ON. The drive control unit 36 (controller) controls the drive circuit 114 (driver) so that the timings at which the main pixel and the sub-pixel are brought into a conductive state (when TFTON is applied) are different. The drive control unit 36 (controller) controls the drive circuit 114 (driver) so that the timing at which one of the main pixel and the sub-pixel is brought from a conductive state to a non-conductive state and the timing at which the other is brought from a non-conductive state to a conductive state overlap.

[0041] The switch element switches between ON (conducting state) and OFF (non-conducting state) using a potential difference of 10 to 20 V. Switching from ON to OFF and OFF to ON can generate unintended charges (gate injection) in the signal line through capacitive coupling formed within the switch element and pixel. Because the charges are of opposite sign when gate injection occurs from ON to OFF and OFF to ON, if the two-dimensional detector 112 (detection unit) only contains normal pixels, the gate injection during readout is almost canceled out in the "OFF → ON → OFF → readout" sequence, with almost no effect on the charges generated by photoelectric conversion. Furthermore, since similarly small effects are superimposed on neighboring pixels, there is almost no effect such as artifacts on the overall image.

[0042] However, when some pixels are divided into main and sub-pixels to form composite pixels, a composite pixel has two switch elements, one for the main pixel and one for the sub-pixel, compared to a single switch element in a normal pixel. If the main pixel switch element and the sub-pixel switch element are turned on simultaneously, the injection that can occur in the composite pixel is twice that of a normal pixel. The initial injection from OFF to ON may exceed the rating of the readout circuit, activating the protection circuit. This may make it impossible to cancel the gate injection when switching from ON to OFF, or may result in a loss of charge due to photoelectric conversion. Even if the protection circuit is not activated, the difference in pixel value between the composite pixel and the adjacent normal pixel may become noticeable as an artifact due to the different effects of gate injection on adjacent pixels.

[0043] In this embodiment, the drive signal Vg2b is controlled to be in the ON state when the drive signal Vg2 is turned OFF. Similarly, the drive signal Vg5b is controlled to be in the ON state when the drive signal Vg5 is turned OFF. According to this embodiment, the timing at which the switch element of the main pixel is turned OFF and the timing at which the switch element of the sub-pixel is turned ON are synchronized to cancel gate injection. This makes it possible to solve the above-mentioned injection-related problems that occur when some pixels are divided into main pixels and sub-pixels as composite pixels.

[0044] The drive control unit 36 can control the drive circuit 114 so that the sum of the time for which the main pixel is conductive and the time for which the sub-pixel is conductive is equal to the time for which the normal pixel is conductive. The time for which the switch element is conductive (ON time) can be expressed as N = Na + Nb. Here, N is the ON time of the switch element in the normal pixel, Na is the ON time of the switch element in the main pixel, and Nb is the ON time of the switch element in the sub-pixel. By controlling the time for which the switch element is conductive in this manner, the charge signal of the sub-pixel can be used when performing automatic exposure control (AEC) in the FPD. In the actual reading operation, the sum of the charge signals of the main pixel and the sub-pixel can be processed equivalently to the charge signal of the normal pixel.

[0045] In addition to analog sampling, analog / digital conversion and digital transfer are also processed in parallel in the readout circuit 113. The timing at which the switch element of a normal pixel is turned on corresponds to the timing at which the switch element of a main pixel is turned on, and the timing at which the switch element of a normal pixel is turned off corresponds to the timing at which the switch element of a sub-pixel is turned off, so that gate injection is applied to the readout circuit 113 at uniform timing. This makes it possible to prevent inter-circuit interference within the readout circuit 113 from causing differences in pixel values between composite pixels and normal pixels.

[0046] Furthermore, it is desirable to set the ON time Na of the switching element of the main pixel to a sufficient time so that the TFT of the normal pixel can transfer the electric charge generated by the photoelectric conversion to the readout circuit 113.

[0047] Furthermore, the ON time Na of the switching element of the main pixel and the ON time Nb of the switching element of the sub-pixel may be different. However, the ratio of the ON times Na and Nb of the switching elements may be proportional to the pixel area of the main pixel and the sub-pixel. In this case, the drive control unit 36 (controller) controls the drive circuit 114 (driver) so that the time (Na) for which the main pixel is in a conductive state and the time (Nb) for which the sub-pixel is in a conductive state correspond to the ratio between the area of the main pixel and the area of the sub-pixel.

[0048] Furthermore, the size of the switch element of the normal pixel may be different from the size of the switch elements of the main pixel and sub-pixel, although the size of the switch elements of the main pixel and sub-pixel may be the same.

[0049] In this way, it is possible to provide a radiation imaging device and a radiation imaging system that can arbitrarily select charge information for multiple regions of interest in automatic exposure control using an FPD, without depending on the setting of the region of interest for automatic exposure or the installation status of the imaging device, and that reduces the occurrence of artifacts.

[0050] (Second embodiment) A second embodiment of the present invention will be described with reference to the accompanying drawings. The schematic configuration of the radiation imaging system 100 according to the second embodiment may be the same as the schematic configuration of the radiation imaging system 100 according to the first embodiment described above, and therefore a description thereof will be omitted here. The second embodiment will be described in detail with reference to Figs. 5 to 7.

[0051] Fig. 5 is a flowchart illustrating the processing flow in the radiation imaging system 100 according to the second embodiment, and Fig. 6 is a timing chart of the drive circuit 114 according to the second embodiment. Imaging drive for automatic exposure amount control in the radiation imaging system 100 according to the second embodiment will be described using Figs. 5 and 6.

[0052] In the flowchart of FIG. 5 and the timing chart of FIG. 6, the pre-reading operation and the main reading operation are the same as those described in the flowchart of FIG. 3 and the timing chart of FIG. 4 for the first embodiment. In the second embodiment, the operations from the start of X-ray irradiation (S503) to the end of X-ray irradiation (S505) differ from those in the first embodiment. In the first embodiment, the X-ray imaging device 30 performs "X-ray stop determination and X-ray irradiation stop control" as automatic exposure amount control while reading out charge signals from the sub-pixels. In the second embodiment, the X-ray imaging device 30 performs pre-reading (S502), charge accumulation in each pixel (S504), and main reading control (S506) to read out the charge accumulated during X-ray irradiation to the readout circuit 113 based on X-ray irradiation start information and irradiation stop information sent from the X-ray generator 12, the X-ray control device 10, the control computer 20, etc. Therefore, sub-pixel reading is not performed during accumulation (S504).

[0053] Here, the control computer 20 determines whether to start X-ray irradiation based on, for example, receiving X-ray irradiation start information sent from the X-ray control device 10 (S503), and outputs the determination result to the X-ray imaging device 30. The X-ray imaging device 30 starts accumulation processing based on receiving the determination result of X-ray irradiation start (S504). Furthermore, the control computer 20 determines whether to stop X-ray irradiation based on, for example, receiving X-ray irradiation stop information sent from the X-ray control device 10 (S505), and outputs the determination result to the X-ray imaging device 30. The X-ray imaging device 30 starts actual reading processing (S506) based on receiving the determination result of X-ray irradiation stop.

[0054] In this way, it is possible to provide a radiation imaging apparatus and a radiation imaging system that reduce the occurrence of artifacts even in normal X-ray imaging without automatic exposure amount control using the FPD of the X-ray imaging device 30.

[0055] Fig. 7 shows another timing chart of the drive circuit 114 according to the second embodiment. In the timing chart of Fig. 7, the accumulation operation and the main reading operation are the same as those in the timing chart of Fig. 6. In the timing chart of Fig. 7, the pre-reading operation is different from that in the timing chart of Fig. 6.

[0056] 6, a conductive voltage (TFTON voltage) that turns on the switch element 101 is applied to the drive wirings G1-2, 2b, 3-5, 5b, and 6 connected to the drive circuit 114 of the two-dimensional detector 112 in this order, thereby resetting the dark current. In contrast, in the pre-reading operation shown in the timing chart of FIG. 7, similar to the main reading operation, the TFTON voltage is applied to the drive signal Vg2b at the timing when the drive signal Vg2 is turned off so as to control the drive signal Vg2b to the ON state. Similarly, the TFTON voltage is applied to the drive signal Vg5b at the timing when the drive signal Vg5 is turned off so as to control the drive signal Vg5b to the ON state, thereby resetting the dark current. That is, as shown in FIG. 7, when resetting the dark current of multiple pixels before radiation irradiation, the drive control unit 36 (controller) controls the drive circuit 114 (driver) so that the timing at which one of the main pixel and the sub-pixel is changed from a conductive state to a non-conductive state and the timing at which the other is changed from a non-conductive state to a conductive state overlap.

[0057] Even in normal imaging without automatic exposure control using an FPD, by resetting the dark current during pre-reading and aligning the dark current during actual reading in this manner, it is possible to provide a radiation imaging device and a radiation imaging system that further reduce the occurrence of artifacts.

[0058] (Third embodiment) A third embodiment of the present invention will be described with reference to the accompanying drawings. The schematic configuration of the radiation imaging system 100 according to the third embodiment may be the same as the schematic configuration of the radiation imaging system 100 according to the first embodiment described above, and therefore a description thereof will be omitted here. The third embodiment will be described in detail with reference to Figs. 8 and 9.

[0059] Fig. 8 is a flowchart illustrating the flow of processing in the radiation imaging system 100 according to the third embodiment, and Fig. 9 shows a timing chart of the drive circuit 114 according to the third embodiment. In the flowchart of Fig. 8 and the timing chart of Fig. 9, the main read operation (S806) is the same as the main read operation described in the flowchart of Fig. 5 and the timing chart of Fig. 6 of the second embodiment. The third embodiment differs from the processing of the second embodiment in the pre-read operation (S802) and the operations from the start of X-ray irradiation (S803) to the end of X-ray irradiation (S805).

[0060] In the second embodiment, the X-ray imaging device 30 performs pre-reading (S502), charge accumulation (S504), and main reading control (S508) to read out the accumulated charge, based on X-ray irradiation start information and irradiation stop information sent from the X-ray generator 12, the X-ray control device 10, the control computer 20, etc. In contrast, in the third embodiment, the X-ray imaging device 30 determines whether to start X-ray irradiation based on charge information b of the sub-pixel during pre-reading, and is controlled to transition to accumulation operation based on the result of the determination of the start of X-ray irradiation.

[0061] In S802, the drive control unit 36 (controller) acquires a signal based on the charge read from the sub-pixel. In S803, the drive control unit 36 (controller) determines whether to start irradiation of radiation based on a change in the signal based on the charge read from the sub-pixel. For example, the drive control unit 36 can determine to start irradiation of radiation when the charge information b becomes equal to or less than a predetermined value.

[0062] Furthermore, in S804, the drive control unit 36 (controller) acquires charge information b of the sub-pixels even during X-ray irradiation, and in S805, the drive control unit 36 (controller) determines whether to stop X-ray irradiation based on the charge information b of the sub-pixels even during X-ray irradiation, calculates the X-ray irradiation amount based on charge information obtained by adding signals based on the charges read out from the sub-pixels, and determines whether to stop X-ray irradiation. Based on the determination result of whether to stop X-ray irradiation, the drive circuit 114 (driver) is controlled to proceed to the main reading operation (S806).

[0063] In this way, it is possible to provide a radiation imaging apparatus and a radiation imaging system that reduce the occurrence of artifacts even in imaging in which the FPD determines whether or not X-ray irradiation is performed without performing automatic exposure amount control using the FPD.

[0064] In the timing charts (FIGS. 4, 6, 7, and 9) described in the above embodiments, the time (ON time) for each pixel to be in a conductive state may be different for each operation in the pre-reading operation, the accumulation operation, and the main reading operation. For example, the drive control unit 36 (controller) may control the drive circuit 114 (driver) so that the time for each of the multiple pixels (normal pixels, main pixels, and sub-pixels) to be in a conductive state before irradiation with radiation is different from the time for each of the multiple pixels (normal pixels, main pixels, and sub-pixels) to be in a conductive state after irradiation with radiation. For example, the conduction time in the pre-reading operation may be longer than the time for each of the multiple pixels (normal pixels, main pixels, and sub-pixels) to be in a conductive state in the main reading operation (e.g., N, Na, and Nb). In this way, by making the conduction time in the pre-reading operation longer than the time of the main reading operation, etc., dark current can be reduced.

[0065] Furthermore, the drive control unit 36 (controller) may control the drive circuit 114 (driver) so that the time during which each of the multiple pixels (normal pixels, main pixels, and sub-pixels) is made conductive before radiation irradiation is shorter than the time (e.g., N, Na, and Nb) during which each of the multiple pixels (normal pixels, main pixels, and sub-pixels) is made conductive after radiation irradiation. The drive control unit 36 (controller) may control the drive circuit 114 (driver) so that the time during which the main pixels and sub-pixels are made conductive before radiation irradiation is shorter than the time (e.g., Na and Nb) during which the main pixels and sub-pixels are made conductive after radiation irradiation. In this way, by shortening the conduction time in the pre-reading operation compared to the time of the main reading operation, etc., the pre-reading operation can be completed in a short time, and the accumulation operation and main reading operation can be started earlier, enabling rapid radiation imaging.

[0066] The disclosure of this specification includes the following radiation imaging apparatus, radiation imaging system, radiation imaging method, and program. (Item 1) a detection unit in which a plurality of pixels are arranged in a matrix, including composite pixels each of which is configured to have a main pixel and a sub-pixel that accumulate electric charges corresponding to a radiation dose and are capable of separately reading out the electric charges; a drive unit connected to a plurality of drive wirings that drives the plurality of pixels row by row into a non-conductive state or a conductive state; a control unit that controls the drive unit and causes the pixels driven row by row to output signals based on the charges, The control unit controlling the driving unit so that the main pixel and the sub-pixel are brought into the conductive state at different timings; a driving unit that controls the driving of the main pixel and the sub-pixel so that the timing at which one of the main pixel and the sub-pixel is changed from the conductive state to the non-conductive state and the timing at which the other of the main pixel and the sub-pixel is changed from the non-conductive state to the conductive state overlap. (Item 2) the plurality of pixels arranged in the detection unit include the composite pixel and a normal pixel that is not configured as the composite pixel, 2. The radiation imaging device according to item 1, wherein the control unit controls the drive unit so that the total time of the time for which the main pixel is in the conductive state and the time for which the sub-pixel is in the conductive state is equal to the time for which the normal pixel is in the conductive state. (Item 3) 3. The radiation imaging device according to item 1 or 2, wherein the control unit controls the drive unit so that the time for which the main pixel is brought into the conductive state and the time for which the sub-pixel is brought into the conductive state correspond to the ratio between the area of the main pixel and the area of the sub-pixel. (Item 4) when performing automatic exposure amount control during radiation irradiation, the control unit controls the drive unit to bring the sub-pixels into the conductive state and the main pixels and the normal pixels into the non-conductive state; 3. The radiation imaging device according to item 2, wherein the driving unit is controlled so as to bring the main pixels, the sub-pixels, and the normal pixels into the non-conductive state when the automatic exposure amount control is not performed. (Item 5) 5. The radiation imaging device according to item 4, wherein the control unit outputs a signal to stop the irradiation of the radiation when charge information obtained by adding signals based on the charges read out from the sub-pixels reaches a threshold value. (Item 6) 5. The radiation imaging apparatus according to item 4, wherein the control unit determines the start of irradiation of the radiation based on a change in a signal based on the charge read out from the sub-pixel. (Item 7) 5. The radiation imaging device according to item 4, wherein the control unit determines whether or not the subject is moving during irradiation of the radiation based on a change in the signal based on the charge read out from the sub-pixel. (Item 8) When the control unit resets the dark currents of the plurality of pixels before the irradiation of the radiation, 8. The radiation imaging device according to any one of items 1 to 7, wherein the driving unit is controlled so that the timing at which one of the main pixel and the sub-pixel is changed from the conductive state to the non-conductive state does not overlap with the timing at which the other of the main pixel and the sub-pixel is changed from the non-conductive state to the conductive state. (Item 9) When the control unit resets the dark currents of the plurality of pixels before the irradiation of the radiation, 9. The radiation imaging device according to any one of items 1 to 8, wherein the driving unit is controlled so that the timing at which one of the main pixel and the sub-pixel is changed from the conductive state to the non-conductive state and the timing at which the other of the main pixel and the sub-pixel is changed from the non-conductive state to the conductive state overlap. (Item 10) 10. The radiation imaging device of claim 1, wherein the control unit controls the drive unit so that a time for which each of the plurality of pixels is brought into the conductive state before the irradiation of the radiation is different from a time for which each of the plurality of pixels is brought into the conductive state after the irradiation of the radiation. (Item 11) 11. The radiation imaging device of claim 1, wherein the control unit controls the drive unit so that a time period during which each of the plurality of pixels is brought into the conductive state before the irradiation of the radiation is shorter than a time period during which each of the plurality of pixels is brought into the conductive state after the irradiation of the radiation. (Item 12) Item 12. The radiation imaging device of item 11, wherein the control unit controls the drive unit so that the time during which the main pixel and the sub-pixel are in the conductive state before the irradiation of the radiation is shorter than the time during which the main pixel and the sub-pixel are in the conductive state after the irradiation of the radiation. (Item 13) the main pixel includes a main conversion element that converts the radiation into an electric charge, and a main switching element that outputs a signal corresponding to the electric charge converted by the main conversion element, the sub-pixel includes a sub-conversion element that converts the radiation into an electric charge, and a sub-switching element that outputs a signal corresponding to the electric charge converted by the sub-conversion element, 13. The radiation imaging device according to any one of items 1 to 12, characterized in that, among the plurality of drive wirings, the main drive wiring to which the main switching element is connected is different from the sub-drive wiring to which the sub-switching element is connected. (Item 14) the main switch element and a switch element of a normal pixel that is not configured as the composite pixel are connected to the main drive wiring, Item 14. The radiation imaging device according to item 13, wherein the sub-switching element of the sub-pixel is connected to the sub-driving wiring. (Item 15) Item 15. The radiation imaging device according to item 14, wherein the drive unit drives the sub-pixels independently of the main pixels and the normal pixels by supplying drive signals to the sub-drive wirings under the control of the control unit. (Item 16) The radiation imaging device according to any one of items 1 to 15, a signal processing means for processing a signal output from the radiation imaging device; A radiation imaging system comprising: (Item 17) a detection unit in which a plurality of pixels are arranged in a matrix, including composite pixels each of which is configured to have a main pixel and a sub-pixel that accumulate electric charges corresponding to a radiation dose and are capable of separately reading out the electric charges; a drive unit to which a plurality of drive wirings are connected, the drive wirings driving the plurality of pixels row by row to a non-conductive state or a conductive state, a control step of controlling the driving unit to output signals based on the charges from the pixels driven row by row, In the control step, controlling the driving unit so that the timings at which the main pixel and the sub-pixel are brought into the conductive state differ from each other; a driving unit that controls the driving of the main pixel and the sub-pixel so that a timing at which one of the main pixel and the sub-pixel is changed from the conductive state to the non-conductive state and a timing at which the other of the main pixel and the sub-pixel is changed from the non-conductive state to the conductive state overlap. (Item 18) Item 18. A program for causing a computer to execute the radiation imaging method according to Item 17.

[0067] [Other embodiments] The disclosed technology can also be realized by supplying a program that realizes one or more functions of the above-described embodiments to a system or device via a network or a storage medium, and having one or more processors in the computer of the system or device read and execute the program. It can also be realized by a circuit (e.g., ASIC) that realizes one or more functions.

[0068] The disclosed technology is not limited to the above-described embodiments, and various changes and modifications can be made without departing from the spirit and scope of the invention. Accordingly, the following claims are appended to apprise the public of the scope of the invention. [Explanation of symbols]

[0069] 10: X-ray control device, 12: X-ray generator, 20: control computer 22: Switch element, 30: X-ray imaging device, 34: Arithmetic unit, 36: drive control unit (control unit), 100: radiation imaging system, 101: Switch element, 102: Conversion element, 103: Bias power supply, 106: Amplification circuit, 107: Sample and hold circuit, 108: multiplexer, 109: buffer amplifier, 110: A / D converter, 111: reference power supply, 112: two-dimensional detector, 113: readout circuit, 114: drive circuit (drive unit)

Claims

1. a detection unit in which a plurality of pixels are arranged in a matrix, including composite pixels each of which is configured to have a main pixel and a sub-pixel that accumulate electric charges corresponding to a radiation dose and are capable of separately reading out the electric charges; a drive unit connected to a plurality of drive wirings that drives the plurality of pixels row by row into a non-conductive state or a conductive state; a control unit that controls the drive unit and causes the pixels driven row by row to output signals based on the charges, The control unit controlling the driving unit so that the main pixel and the sub-pixel are brought into the conductive state at different timings; a driving unit that controls the driving of the main pixel and the sub-pixel so that the timing at which one of the main pixel and the sub-pixel is changed from the conductive state to the non-conductive state and the timing at which the other of the main pixel and the sub-pixel is changed from the non-conductive state to the conductive state overlap.

2. the plurality of pixels arranged in the detection unit include the composite pixel and a normal pixel that is not configured as the composite pixel, 2. The radiation imaging device according to claim 1, wherein the control unit controls the drive unit so that a total time of a time for which the main pixel is in the conductive state and a time for which the sub-pixel is in the conductive state is equal to a time for which the normal pixel is in the conductive state.

3. 2. The radiation imaging device according to claim 1, wherein the control unit controls the drive unit so that a time period during which the main pixel is brought into the conductive state and a time period during which the sub-pixel is brought into the conductive state correspond to a ratio between an area of the main pixel and an area of the sub-pixel.

4. when performing automatic exposure amount control during radiation irradiation, the control unit controls the drive unit to bring the sub-pixels into the conductive state and the main pixels and the normal pixels into the non-conductive state; 3. The radiation imaging apparatus according to claim 2, wherein the driving unit is controlled so as to bring the main pixels, the sub-pixels, and the normal pixels into the non-conductive state when the automatic exposure amount control is not performed.

5. 5. The radiation imaging device according to claim 4, wherein the control unit outputs a signal to stop the irradiation of the radiation when charge information obtained by adding signals based on the charges read out from the sub-pixels reaches a threshold value.

6. 5. The radiation imaging apparatus according to claim 4, wherein the control unit determines the start of irradiation of the radiation based on a change in a signal based on the charge read out from the sub-pixel.

7. The radiation imaging apparatus according to claim 4 , wherein the control unit determines whether or not the subject is moving during irradiation of the radiation based on a change in a signal based on the charge read out from the sub-pixel.

8. When the control unit resets the dark currents of the plurality of pixels before the irradiation of the radiation, 2. The radiation imaging device according to claim 1, wherein the driving unit is controlled so that the timing at which one of the main pixel and the sub-pixel is changed from the conductive state to the non-conductive state does not overlap with the timing at which the other of the main pixel and the sub-pixel is changed from the non-conductive state to the conductive state.

9. When the control unit resets the dark currents of the plurality of pixels before the irradiation of the radiation, 2. The radiation imaging device according to claim 1, wherein the driving unit is controlled so that a timing at which one of the main pixel and the sub-pixel is changed from the conductive state to the non-conductive state and a timing at which the other of the main pixel and the sub-pixel is changed from the non-conductive state to the conductive state overlap.

10. 2. The radiation imaging device according to claim 1, wherein the control unit controls the drive unit so that a time for which each of the plurality of pixels is brought into the conductive state before the irradiation of the radiation is different from a time for which each of the plurality of pixels is brought into the conductive state after the irradiation of the radiation.

11. 2. The radiation imaging device according to claim 1, wherein the control unit controls the drive unit so that a time period during which each of the plurality of pixels is brought into the conductive state before the irradiation of the radiation is shorter than a time period during which each of the plurality of pixels is brought into the conductive state after the irradiation of the radiation.

12. 12. The radiation imaging device according to claim 11, wherein the control unit controls the drive unit so that a time during which the main pixel and the sub-pixel are brought into the conductive state before the irradiation of the radiation is shorter than a time during which the main pixel and the sub-pixel are brought into the conductive state after the irradiation of the radiation.

13. the main pixel includes a main conversion element that converts the radiation into an electric charge, and a main switching element that outputs a signal corresponding to the electric charge converted by the main conversion element, the sub-pixel includes a sub-conversion element that converts the radiation into an electric charge, and a sub-switching element that outputs a signal corresponding to the electric charge converted by the sub-conversion element, 2. The radiation imaging apparatus according to claim 1, wherein, of the plurality of drive wirings, a main drive wiring to which the main switching element is connected is different from a sub-drive wiring to which the sub-switching element is connected.

14. the main switch element and a switch element of a normal pixel that is not configured as the composite pixel are connected to the main drive wiring, 14. The radiation imaging apparatus according to claim 13, wherein the sub-switching element of the sub-pixel is connected to the sub-driving wiring.

15. 15. The radiation imaging apparatus according to claim 14, wherein the drive section drives the sub-pixels independently of the main pixels and the normal pixels by supplying drive signals to the sub-drive wirings under the control of the control section.

16. The radiation imaging device according to any one of claims 1 to 15, a signal processing means for processing a signal output from the radiation imaging device; A radiation imaging system comprising:

17. a detection unit in which a plurality of pixels are arranged in a matrix, including composite pixels each of which is configured to have a main pixel and a sub-pixel that accumulate electric charges corresponding to a radiation dose and are capable of separately reading out the electric charges; a drive unit to which a plurality of drive wirings are connected, the drive wirings driving the plurality of pixels row by row to a non-conductive state or a conductive state, a control step of controlling the driving unit to output signals based on the charges from the pixels driven row by row, In the control step, controlling the driving unit so that the timings at which the main pixel and the sub-pixel are brought into the conductive state differ from each other; a driving unit that controls the driving of the main pixel and the sub-pixel so that a timing at which one of the main pixel and the sub-pixel is changed from the conductive state to the non-conductive state and a timing at which the other of the main pixel and the sub-pixel is changed from the non-conductive state to the conductive state overlap.

18. A program for causing a computer to execute the radiation imaging method according to claim 17.

Images