JP2016027889A - Radiation image detector and radiation imaging system - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a radiation image detector that detects irradiation on the basis of an electric signal output from a pixel and reduces power consumption of the detector.SOLUTION: An image data generation unit is configured so as to include an amplifier unit 60 for amplifying an electric signal output from each pixel for image detection and a data processing unit 61 for converting the electric signal amplified by the amplifier unit to image data and be capable of independently supplying operation power to each of the amplifier unit 60 and the data processing unit 61. A control unit stops supplying operation power to the data processing unit 61 until an irradiation detection unit detects irradiation in an irradiation detection mode and, when the irradiation detection unit has detected irradiation, shifts into an imaging mode to start supplying operation power to the data processing unit 61.SELECTED DRAWING: Figure 5

Description

  The present invention relates to a radiation image detection apparatus and a radiation imaging system.

  X-ray imaging is widely used in fields such as medical diagnosis and nondestructive inspection. In general X-ray photography, a subject is irradiated with X-rays, X-rays that are attenuated at each part of the subject and transmitted through the subject are detected, and an X-ray image of the subject is obtained based on the intensity distribution. Yes.

  As a detection medium for detecting X-rays, in recent years, a flat has a two-dimensional array of pixels that generate charges when irradiated with X-rays, and generates image data based on electrical signals output from each pixel. A panel detector (FPD) is used. For X-ray imaging, so-called electronic cassettes configured by housing the FPD in a portable housing are also widely used.

  An FPD configured to detect X-ray irradiation based on an electrical signal output from a pixel is also known (see, for example, Patent Documents 1 and 2). In the FPD described in Patent Document 1, all pixels are used for both image acquisition and irradiation detection. In the FPD described in Patent Document 2, irradiation detection is performed separately from the image detection pixels. Pixels are provided.

  According to the FPD configured to detect the X-ray irradiation based on the electric signal output from the pixel, it is necessary to synchronize the FPD with the console that controls the operation of the X-ray irradiation apparatus or the X-ray irradiation apparatus. Eliminates operability.

JP 2003-126072 A JP 2011-174908 A

  In the electronic cassette, a battery is mounted to ensure its portability, and the operating power of each part of the FPD is supplied by the battery. Therefore, reduction of power consumption is required.

  The output signal of each pixel is amplified by an amplifier, and an amplifier for amplifying the output signal of the image detection pixel is typically provided for each pixel column in the two-dimensional array of pixels. Therefore, a signal processing circuit that generates image data based on an output signal of an image detection pixel includes a large number of amplifiers and analogs such as A / D converters that convert signals output from these amplifiers into digital data. An element is provided and its operating power is relatively large.

  As in the FPD described in Patent Document 1, when all pixels are used for image acquisition and irradiation detection, a signal processing circuit for generating image data including a number of amplifiers until X-ray irradiation is performed. However, since it is necessary to continue supplying the operating power to the battery, there is a concern about battery consumption.

  On the other hand, like the FPD described in Patent Document 2, when a signal processing circuit that detects X-ray irradiation based on the output signal of the irradiation detection pixel and the irradiation detection pixel is provided separately, the irradiation detection pixel is Compared to image detection pixels, a very small number of amplifiers are required, and an amplifier for amplifying the output signals of these irradiation detection pixels is also very small. Therefore, the operating power of the signal processing circuit for irradiation detection is for image data generation. It is smaller than the operating power of the signal processing circuit. Therefore, even if the supply of operating power to the signal processing circuit for irradiation detection is continued until the X-ray is irradiated, the power consumption can be reduced.

  However, when the standby period is relatively long, charges are accumulated in the pixels due to dark current or the like. Therefore, even in the FPD described in Patent Document 2, image data generation is performed in order to reset the image detection pixels. It is necessary to periodically drive the signal processing circuit. In this case, there is room for improvement in further reducing power consumption with respect to the supply of operating power to the signal processing circuit for generating image data.

  The present invention has been made in view of the above-described circumstances, and an object thereof is to reduce power consumption in a radiation image detection apparatus that detects radiation irradiation based on an electrical signal output from a pixel. .

  Based on an image receiving unit having a two-dimensional array of a plurality of image detection pixels and at least one irradiation detection pixel that generate a charge when irradiated with radiation, and an electrical signal output from each of the image detection pixels An image data generation unit that generates image data, an irradiation detection unit that detects radiation irradiation based on an electrical signal output from each of the irradiation detection pixels, an imaging mode that generates image data, and radiation irradiation detection A control unit having a plurality of control modes including an irradiation detection mode to be performed, wherein the image data generation unit amplifies an electrical signal output from each of the image detection pixels, and the first A data processing unit for converting the electric signal amplified by the amplifier unit into image data, and each of the first amplifier unit and the data processing unit is operated independently. The control unit stops supplying the operating power to the data processing unit until radiation irradiation is detected by the irradiation detection unit in the irradiation detection mode. A radiation image detection apparatus that transitions to the imaging mode and starts supplying operating power to the data processing unit when radiation irradiation is detected by the irradiation detection unit.

  ADVANTAGE OF THE INVENTION According to this invention, the power consumption can be reduced in the radiographic image detection apparatus which detects irradiation of a radiation based on the electrical signal output from a pixel.

It is a figure showing typically composition of an example of a radiography system for describing an embodiment of the present invention. It is a figure which shows the control block of the radiography system of FIG. It is a figure which shows the structure of the radiographic image detection apparatus in the radiography system of FIG. It is a figure which shows the structure of the radiographic image detector in the radiographic image detection apparatus of FIG. It is a figure which shows the circuit structure of the image data generation part of the radiographic image detector of FIG. It is a figure which shows the circuit structure of the irradiation detection part of the radiographic image detector of FIG. It is a figure which shows the operation | movement flow of the console in the radiography system of FIG. It is a figure which shows the operation | movement flow of the radiographic image detection apparatus in the radiography system of FIG. It is a figure which shows the operation | movement timing of each part of the radiographic image detection apparatus in the radiography system of FIG. It is a figure which shows the circuit structure of the irradiation detection part in the modification of the radiographic image detection apparatus of FIG. It is a figure which shows the operation | movement timing of each part of the radiographic image detection apparatus of FIG.

  The X-ray imaging system 1 is roughly divided into an X-ray imaging apparatus 2 and a console 3. The X-ray imaging apparatus 2 detects an X-ray source 11 that irradiates the subject H with X-rays, and an X-ray cassette that generates image data by detecting the X-rays emitted from the X-ray source 11 and transmitted through the subject H. X-ray image detection device) 12. The console 3 controls the operation of each part of the X-ray imaging apparatus 2 such as the X-ray source 11 and the electronic cassette 12 based on the operation of the operator.

  In the radiographing room in which the X-ray imaging apparatus 2 is installed, a standing radiographing stand 13 used for performing standing radiographing and a supine radiographing table 14 used for performing prone radiography are installed. . The electronic cassette 12 is held on the standing position imaging table 13 when performing the standing position shooting, and is held on the lying position imaging table 14 when performing the position shooting.

  In addition, the X-ray source 11 is rotated around a horizontal axis (in the direction of arrow a in FIG. 1) in the radiographing room so that a single X-ray source 11 can be used for standing-up imaging and supine imaging. A support moving mechanism 15 is provided that supports the movable in the vertical direction (arrow b direction in FIG. 1) and further in the horizontal direction (arrow c direction in FIG. 1). The support moving mechanism 15 includes a drive source that rotates the X-ray source 11 about a horizontal axis, a drive source that moves the X-ray source 11 in the vertical direction, and a drive source that moves the X-ray source 11 in the horizontal direction. These drive sources are controlled by the console 3 based on an operator's setting operation on the console 3.

  The console 3 is configured as a server computer, and is acquired by the control device 20 including a CPU, a ROM, a RAM, and the like, an input device 21 for an operator to input imaging information and an exposure instruction, and the electronic cassette 12. An image processing unit 22 that performs appropriate image processing on the X-ray image data, an image storage unit 23 that stores the X-ray image data that has been subjected to image processing, and imaging information or an image input by the input device 21 A monitor 24 for displaying X-ray image data generated in the processing unit 22 and an interface (I / F) 25 connected to each unit of the X-ray imaging system 1 are connected via a bus 26. Has been.

  The interface 25 transmits / receives various information such as an exposure condition described later to / from the X-ray source 11 by wired or wireless communication, and transmits / receives various information such as image data to / from the electronic cassette 12. .

  FIG. 3 shows the configuration of the electronic cassette 12.

  The electronic cassette 12 includes an FPD 30, a battery 31 that supplies operating power to each part of the FPD 30, and a housing 32 that houses the FPD 30 and the battery 31. The X-ray transmitted through the subject passes through the top plate portion 32a of the housing 32 and enters the image receiving portion of the FPD 30 housed inside the housing.

  As a material for forming the housing 32, it is formed of a material having excellent X-ray transmittance. For example, carbon fiber (carbon fiber), aluminum, magnesium, bionanofiber (cellulose microfibril) in consideration of strength-weight ratio and the like. Or a composite material or the like. As the composite material, for example, a material including a reinforced fiber resin is used, and the reinforced fiber resin includes carbon, cellulose, and the like. Specifically, as the composite material, carbon fiber reinforced plastic (CFRP), a structure in which a foamed material is sandwiched with CFRP, or a material in which the surface of the foamed material is coated with CFRP is used.

  FIG. 4 shows the configuration of the FPD 30.

  The FPD 30 includes an image receiving unit 40 in which a plurality of pixels 41 that receive X-rays and generate charges are two-dimensionally arranged on an active matrix thin film transistor (TFT) array substrate.

The pixel 41 directly converts X-rays into electric charges by a conversion layer (not shown) such as amorphous selenium, and stores the converted electric charges in a capacitor 42 connected to the lower electrode of the conversion layer. It is configured as a detection element. Note that the pixel 41 was converted into visible light once by a scintillator made of gadolinium oxide (Gd ₂ O ₃ ), gadolinium sulfate (Gd ₂ O ₂ S), cesium iodide (CsI), or the like. It is also possible to configure as an indirect conversion type X-ray detection element that converts visible light into electric charge by a photodiode and accumulates it.

  Of the pixel group, at least one pixel 41 is used to detect X-ray irradiation, and the remaining pixels 41 are used to detect an X-ray image. Hereinafter, the pixel 41 for detecting an X-ray image is referred to as an image detection pixel 41a, and the pixel 41 for detecting X-ray irradiation is referred to as an irradiation detection pixel 41b.

  It is sufficient if at least one irradiation detection pixel 41b is provided in the two-dimensional array of pixels 41, but a plurality of irradiation detection pixels 41b are preferably provided in a distributed manner. For example, even when a substance having a relatively high X-ray absorption ability such as a bone part of the subject H is arranged on some of the irradiation detection pixels 41b, such an X-ray high absorption substance does not overlap. In the pixel 41b, sufficient charges are generated along with the X-ray irradiation, and X-ray irradiation detection can be reliably performed based on the charges generated in the pixels 41b.

  The TFT array substrate is provided with a TFT switch element 43 corresponding to each pixel 41, a gate line 44 for each row in the two-dimensional array of the pixels 41, and a data line 45 for each column. . Each TFT switch element 43 has a gate electrode connected to the gate line 44, a source electrode connected to the capacitor 42 of the corresponding pixel 41, and a drain electrode connected to the data line 45.

  Further, the TFT array substrate is provided with a signal line 46 connected between the capacitor 42 and the TFT switch element 43 of each irradiation detection pixel 41b. In the illustrated example, one irradiation detection pixel 41 b is provided in each of a plurality of rows, and a signal line 46 is provided in each row in which the irradiation detection pixels 41 b are provided. Two irradiation detection pixels 41b are connected. A plurality of irradiation detection pixels 41 b may be connected to each signal line 46.

  Then, the FPD 30 controls the timing for reading out the charges accumulated in the image detection pixels 41a, and the image data generation unit 51 generates image data based on the charges read out from the image detection pixels 41a. A communication unit 52 that transmits the image data generated in the image data generation unit 51 to the console 3, an irradiation detection unit 53 that detects X-ray irradiation based on the charges read from each irradiation detection pixel 41b, A power supply unit 54 that includes the battery 31 and supplies the operating power of each part of the FPD 30; and a control unit 55 that controls the operation power supply from the power supply part 54 to each part of the FPD 30 and controls the operation of each part of the FPD 30. I have.

  Each gate line 44 is connected to the scanning unit 50, and each data line 45 is connected to the image data generation unit 51. The scanning unit 50 supplies a driving pulse to the TFT switch element 43 through the gate line 44, and turns on the TFT switch element 43. The charge accumulated in the image detection pixel 41 a connected to the TFT switch element 43 that is turned on is read out as the TFT switch element 43 is turned on and connected to the TFT switch element 43. The transmitted data line 45 is transmitted as an electrical signal and input to the image data generation unit 51.

  On the other hand, each signal line 46 is connected to the irradiation detection unit 53. The electric charges accumulated in each irradiation detection pixel 41 b are transmitted through the signal line 46 as an electric signal and input to the irradiation detection unit 53 regardless of whether the TFT switch element 43 corresponding to the pixel 41 b is turned on or off.

  FIG. 5 shows a circuit configuration of the image data generation unit 51.

  The image data generation unit 54 includes an amplifier unit 60 that amplifies the electrical signal output from each image detection pixel 41a, and a data processing unit 61 that converts the electrical signal amplified by the amplifier unit 60 into image data. ing.

  The amplifier unit 60 includes a plurality of variable gain preamplifiers (charge amplifiers) 62 provided corresponding to the plurality of data lines 45, and each variable gain preamplifier 62 includes an operational amplifier 62a whose positive input side is grounded. And a capacitor 62b connected in parallel between the negative input side and the output side of the operational amplifier 62a, and a reset switch 62c. The data line 45 is connected to the negative input side of the operational amplifier 62a. Yes. ON / OFF switching of the reset switch 62c is controlled by the control unit 55.

  The data processing unit 61 includes a plurality of sample and hold circuits 63 provided corresponding to each of the plurality of variable gain preamplifiers 62 of the amplifier unit 60, a multiplexer 64, and an analog / digital (A / D) converter 65. Have. The multiplexer 64 is configured to include a switch 64 a for sequentially selecting inputs from the plurality of sample and hold circuits 63. The sample timing of the sample hold circuit 63 and the input selection by the switch 64a of the multiplexer 64 are controlled by the control unit 55.

  The electronic cassette 12 is configured to be able to supply operating power to the amplifier unit 60 and the data processing unit 61 independently of each other. The supply of operating power to the amplifier unit 60 and the data processing unit 61 is controlled. Controlled by the unit 55.

  When an X-ray image is detected, a driving pulse is supplied from the scanning unit 50 to the TFT switch element 43 via the gate line 44, and the TFT switch element 43 is turned on in units of rows. Among the image detection pixels 41a that have accumulated charges in the capacitor 42 by being irradiated with X-rays, charges are read from the image detection pixels 41a connected to the TFT switch elements 43 that are turned on, The read charge is transmitted as an electric signal through the data line 45 connected to the TFT switch element 43 and is input to the corresponding variable gain preamplifier 62.

  The electric signal input to the variable gain preamplifier 62 is amplified by the variable gain preamplifier 62 at a predetermined amplification factor.

  Each sample and hold circuit 63 is driven for a predetermined period, and the signal level of the electric signal (voltage signal) amplified by the corresponding variable gain preamplifier 62 is held in the sample and hold circuit 63. The signal levels held in each sample and hold circuit 63 are sequentially selected by the switch 64a of the multiplexer 64, input to the A / D converter 65, and A / D converted.

  An image memory 56 is connected to the image data generation unit 51, and pixel data output from the A / D converter 65 is stored in order in the image memory 56.

  Then, the reset switch 62c of each variable gain preamplifier 62 is turned on for a predetermined period. As a result, the charge read from the image detection pixel 41a and accumulated in the capacitor 62b is discharged. Each image detection pixel 41a is reset after the charge from the capacitor 42 is read out and discharged in the capacitor 62b that stores the read out charge.

  The above-described readout of charges from the image detection pixels 41a is sequentially performed row by row, and X-ray image data is generated.

  The pixel data of the X-ray image at the arrangement position of each irradiation detection pixel 41b is generated by interpolating using the pixel data obtained by the image detection pixel 41a located around the irradiation detection pixel 41b. Is done. Such defective pixel correction processing can be performed, for example, in the image processing unit 22 of the console 3.

  FIG. 6 shows a circuit configuration of the irradiation detection unit 53.

  The irradiation detection unit 53 includes an amplifier unit 70 that amplifies the electric signal output from each irradiation detection pixel 41b, and a determination unit 71 that determines an X-ray irradiation state based on the electric signal amplified by the amplifier unit 70. It is equipped with.

  The amplifier unit 70 includes a plurality of variable gain preamplifiers (charge amplifiers) 72 provided corresponding to the plurality of signal lines 46, and each variable gain preamplifier 72 includes an operational amplifier 72a whose positive input side is grounded. And a capacitor 72b connected in parallel between the negative input side and the output side of the operational amplifier 72a, and a reset switch 72c. ON / OFF switching of the reset switch 72c is controlled by the control unit 55.

  The determination unit 71 includes a comparator 73. The comparator 73 is connected to an operational amplifier 73a, a positive input side of the operational amplifier 73a, a capacitor 73b that supplies a reference electric signal to the positive input side, and an operational amplifier 73a. A switch 73c that connects the negative input side and the capacitor 73b is included. The output terminals of the variable gain preamplifiers 72 of the amplifier unit 70 are connected in parallel to the negative input side of the operational amplifier 73a. ing. ON / OFF switching of the switch 73c is controlled by the control unit 55, and the signal level of the electric signal input to the negative input side of the operational amplifier 73a is held in the capacitor 73b by turning on the switch 73c for a predetermined period. Is done.

  The supply of operating power to the amplifier unit 70 and the determination unit 71 is controlled by the control unit 55, and the operation power is supplied to the amplifier unit 70 and the determination unit 71 at a predetermined cycle. Therefore, the irradiation detection operation is periodically performed.

  In the irradiation detection operation, the amplifier unit 70 and the determination unit 71 are driven, and accordingly, the charge accumulated in the capacitor 42 of each irradiation detection pixel 41b is applied to the signal line 46 connected to the irradiation detection pixel 41b. It is transmitted as an electrical signal and input to the corresponding variable gain preamplifier 72.

  The electric signal input to each variable gain preamplifier 72 is amplified by the variable gain preamplifier 72 at a predetermined amplification factor.

  The electric signal (voltage signal) amplified by each variable gain preamplifier 72 is input to the comparator 73 of the determination unit 71 in parallel. In the comparator 73, the signal level of the input electrical signal (hereinafter referred to as the input signal level) is compared with the signal level of the reference electrical signal held in the capacitor 73b (hereinafter referred to as the reference signal level). Is called.

  Here, the input signal level in the previous irradiation detection operation is held in the capacitor 73b. After the comparison between the input signal level and the reference signal level is completed, the switch 73c of the comparator 73 is turned on for a predetermined period, and the input signal level at that time is held in the capacitor 73b. Here, the signal level held in the capacitor 73b becomes the reference signal level in the next irradiation detection operation.

  When X-ray irradiation is performed, charges corresponding to the received X-ray dose are accumulated in at least one irradiation detection pixel 41b, and the input signal level to the comparator 73 becomes larger than the reference signal level and is detected from the comparator 73. A signal (typically, an electric signal having a signal level of either the positive voltage or the negative voltage of the operating voltage supplied to the comparator 73) is output.

  The detection signal output from the comparator 73 is input to the control unit 55, and the control unit 55 switches the control mode based on the input detection signal. The control mode will be described later.

  Then, the reset switch 72c of each variable gain preamplifier 72 is turned on for a predetermined period, and the charge read from the irradiation detection pixel 41b and accumulated in the capacitor 72b is discharged. Each irradiation detection pixel 41b is reset after the charge from the capacitor 42 is read out and discharged in the capacitor 72b that stores the read out charge.

  FIG. 7 shows an operation flow of the console 3.

  First, photographing information is input on the console 3 (step S1). As the imaging information, the name of the subject to be imaged, the region to be imaged, the exposure condition of the radiation X at the time of imaging (in this embodiment, the tube voltage, tube current, And the exposure period).

  When the input of the photographing information is completed, the console 3 transmits a control signal indicating the completion of the input to the electronic cassette 12. Further, the console 3 transmits the exposure conditions included in the imaging information to the X-ray source 11 (step S2). In the X-ray source 11, preparation for exposure is performed according to the received exposure conditions.

  Then, after preparation for imaging such as positioning of the X-ray source 11, the electronic cassette 12 and the subject is completed, an exposure instruction is given on the console 3. The console 3 transmits a control signal indicating an exposure instruction to the X-ray source 11 (step S3). In the X-ray source 11, X-rays are irradiated according to the previously set exposure conditions, and X-ray image data is acquired by the electronic cassette 12.

  Next, the X-ray image data acquired by the imaging is transmitted from the electronic cassette 12 to the console 3 (step S4), and the console 3 performs image processing such as the above-described defective pixel compensation on the received X-ray image data. (Step S5), the X-ray image data subjected to the image processing is stored in the image storage unit 23, and the X-ray image indicated by the X-ray image data is displayed on the monitor 24 (step S6).

  FIG. 8 shows an operation flow of the electronic cassette 12.

  First, the main power supply of the electronic cassette 12 is turned on, and each part of the electronic cassette 12 is initialized (step SS1). Then, after the initialization, the electronic cassette 12 shifts to the standby mode (Step SS2). In the standby mode, operating power is supplied only to the communication unit 52 and the control unit 55, and the electronic cassette 12 waits until it receives a control signal indicating the end of input of imaging information from the console 3 (step SS3).

  The electronic cassette 12 shifts from the standby mode to the irradiation detection mode when receiving a control signal indicating the end of input of photographing information in the console 3 (step SS4).

  In the irradiation detection mode, until the X-ray irradiation is detected, the electronic cassette 12 discharges the electric charge accumulated in each image detection pixel 41a by dark current, so that the image detection pixel 41a to be described later periodically. Reset operation is performed (step SS5). Further, the electronic cassette 12 periodically performs an irradiation detection operation (Step SS6).

  When detecting the X-ray irradiation (Step SS7), the electronic cassette 12 shifts from the irradiation detection mode to the imaging mode (Step SS8), starts the X-ray image detection operation described above, and generates X-ray image data. (Step SS9). Then, the electronic cassette 12 transmits the X-ray image data generated by the imaging to the console 3 (Step SS10).

  After the X-ray image data has been transmitted, for example, the electronic cassette 12 may be configured to shift to the standby mode, or temporarily shifts to the irradiation detection mode in preparation for re-imaging (re-shooting). The electronic cassette 12 may be configured to shift to the standby mode after a predetermined time has elapsed.

  FIG. 9 shows the operation timing of each part of the electronic cassette 12 in the irradiation detection mode and the imaging mode.

  In the irradiation detection mode, the irradiation detection operation is periodically performed as described above. That is, according to control by the control unit 55, operating power is periodically supplied from the power supply unit 54 to the irradiation detection unit 53 (the amplifier unit 70 and the determination unit 71), and the irradiation detection unit 53 is periodically driven. As described above, by periodically performing the irradiation detection operation and periodically supplying the operating power from the power supply unit 54 to the irradiation detection unit 53, the power consumption in the irradiation detection unit 53 can be reduced.

  As the irradiation detection unit 53 is driven, the electric charge accumulated in each irradiation detection pixel 41 b is read out, amplified by the amplifier unit 70, and then input to the determination unit 71. Then, the comparator 73 of the determination unit 71 compares the input signal level with the reference signal level held in the capacitor 73b of the comparator 73.

  For each irradiation detection operation, at the end of the operation period, the switch 73c of the comparator 73 is turned on for a predetermined period according to the writing control by the control unit 55, and the input signal level at that time is held in the capacitor 73b. Therefore, the input signal level is compared with the input signal level in the previous irradiation detection operation, and irradiation detection is performed based on the difference between both signal levels.

  Even when X-ray irradiation is not performed, charges due to a dark current are accumulated in the irradiation detection pixel 41b during a pause period of the irradiation detection operation. When performing the irradiation detection operation periodically, as described above, by performing irradiation detection based on the difference between the input signal level and the input signal level in the previous irradiation detection operation, the influence of the charge due to the dark current is eliminated. Thus, irradiation detection can be performed more accurately.

  When X-ray irradiation is performed, charges corresponding to the received X-ray dose are accumulated in at least one irradiation detection pixel 41b, so that a difference of a certain level or more occurs between the input signal level and the reference signal level. Accordingly, a detection signal is output from the determination unit 71 to the control unit 55. The controller 55 shifts to the shooting mode based on the input detection signal.

  In the irradiation detection mode, the reset operation of the image detection pixel 41a is periodically performed. In the illustrated example, a driving pulse is supplied from the scanning unit 50 to the TFT switch element 43 via the gate line 44, and the TFT switch element 43 is sequentially turned on line by line. The charge accumulated by the dark current is read from the image detection pixel 41a connected to each TFT switch element 43 that is turned on, and the read charge is connected to the TFT switch element 43. The data is accumulated in the capacitor 62 b of the variable gain preamplifier 62 corresponding to the amplifier unit 60 via the data line 45. Then, the reset switch 62c of each variable gain preamplifier 62 is turned on for a predetermined period, the charge accumulated in the capacitor 62b is discharged, and the image detection pixel 41a is reset. Note that in relation to the rated input of the variable gain preamplifier 62, the TFT switch elements 43 in a plurality of rows or all rows are turned on, and the image detection pixels 41a in a plurality of rows or all rows are reset at once. Also good.

  Here, in the above-described reset operation of the image detection pixel 41a, it is not necessary to generate image data, and therefore it is not necessary to operate the data processing unit 61. Therefore, in the electronic cassette 12, as described above, the supply of operating power from the power supply unit 54 to the amplifier unit 60 and the data processing unit 61 can be controlled independently from each other by the control unit 55. In the irradiation detection mode, Operating power is supplied only to the amplifier unit 60. Thereby, power consumption in the image data generation unit 51 can be reduced.

  In the electronic cassette 12, the supply of operating power to the amplifier unit 60 is periodically performed in synchronization with the reset operation of the image detection pixels 41a. Thereby, the power consumption in the image data generation unit 51 can be further reduced.

Further, the operation period T ₁ of the irradiation detection operation, it is preferable to shorter than the operation cycle T ₂ of the reset operation of the image detection pixels 41a. In order to make effective use of the irradiated X-ray energy, it is preferable to detect the irradiation as fast as possible and to quickly start the charge accumulation from the pixel reset. Since the image detection pixel 41a is the number of pixels is much larger than the radiation detection pixels 41b, by shortening the operation period T ₁ of the irradiation detecting operation than the operation period T ₂ of the reset operation of the image sensing pixels 41a, irradiation detecting Can be performed at high speed.

  When the irradiation detection unit 53 detects X-ray irradiation and shifts to the imaging mode, charges are accumulated in each image detection pixel 41a during the X-ray irradiation period.

  After shifting to the imaging mode, the supply of operating power to the irradiation detection unit 53 (the amplifier unit 70 and the determination unit 71) is also stopped. In addition, during the X-ray irradiation period, charges are not read from the image detection pixels 41a, and the supply of operating power to the image data generation unit 51 (the amplifier unit 60 and the data processing unit 61) is stopped. Thereby, power consumption is reduced.

  After the X-ray irradiation is completed, operating power is supplied to the amplifier unit 60 and the data processing unit 61 of the image data generation unit 51, and the charges are read from the image detection pixels 41a one by one in order. Image data is generated. Then, the generated X-ray image data is transmitted to the console 3.

  FIG. 10 shows a circuit configuration of the irradiation detection unit of the modified example of the electronic cassette 12 described above.

  In the electronic cassette 12 described above, all the variable gain preamplifiers 72 included in the amplifier unit 70 of the irradiation detection unit 53 are driven in accordance with the supply of operating power to the irradiation detection unit 53 of the FPD 30. The electronic cassette 112 shown in FIG. 10 is configured to be able to supply operating power independently to each of the variable gain preamplifiers 72, and the supply of operating power to each variable gain preamplifier 72 is controlled by the control unit 55. Other configurations are the same as those of the electronic cassette 12 described above, and a description thereof will be omitted.

  FIG. 11 shows the operation timing of each part of the electronic cassette 112 in the irradiation detection mode and the imaging mode.

  In the irradiation detection mode, an irradiation detection operation is periodically performed. However, for each irradiation detection operation, one variable gain preamplifier 72 is sequentially selected in the amplifier unit 70 of the irradiation detection unit 53, and operating power is supplied only to the selected variable gain preamplifier 72. The determination unit 71 is supplied with operating power for each irradiation detection operation.

  In this case, the charge accumulated in the irradiation detection pixel 41b connected to the signal line 46 corresponding to the selected variable gain preamplifier 72 is read and amplified in the selected variable gain preamplifier 72, and then the determination is made. Input to the unit 71. Then, in the comparator 73 of the determination unit 71, the input signal level is compared with the reference signal level held in the capacitor 73b of the comparator 73, and irradiation detection is performed based on the difference between the two signal levels.

  According to the above configuration, the power consumption of the irradiation detection unit 53 can be reduced as compared with the case where all the variable gain preamplifiers 72 included in the amplifier unit 70 are driven for each irradiation detection operation. In this example, it has been described that one variable gain preamplifier 72 is selected and driven in the amplifier unit 70 of the irradiation detection unit 53 for each irradiation detection operation. However, some of the variable components included in the amplifier unit 70 are driven. As long as the gain preamplifier 72 is selected and driven, the above effect can be obtained.

  In the above description, the case where general X-rays are used as radiation has been described, but the present invention is not limited to X-rays, and radiation other than X-rays such as α-rays and γ-rays can be used. It is.

  As described above, the present specification discloses the following (1) to (8) radiation image detection apparatuses and the following (9) radiation imaging system.

(1) An image receiving unit having a two-dimensional array of a plurality of image detection pixels and at least one irradiation detection pixel that generate charges when irradiated with radiation, and an electric signal output from each of the image detection pixels An image data generation unit that generates image data based on the above, an irradiation detection unit that detects radiation irradiation based on an electrical signal output from each of the irradiation detection pixels, an imaging mode for generating image data, and a radiation A control unit having a plurality of control modes including an irradiation detection mode for performing irradiation detection, and the image data generation unit includes a first amplifier unit that amplifies an electrical signal output from each of the image detection pixels; A data processing unit that converts the electrical signal amplified by the first amplifier unit into image data, and independently of each of the first amplifier unit and the data processing unit. The control unit is configured to be able to supply operating power, and the control unit stops supplying operating power to the data processing unit until radiation irradiation is detected by the irradiation detection unit in the irradiation detection mode. Then, when radiation irradiation is detected by the irradiation detection unit, the radiographic image detection apparatus shifts to the imaging mode and starts supplying operating power to the data processing unit.
(2) The radiological image detection apparatus according to (1), wherein the control unit periodically operates the irradiation detection unit by supplying operation power to the irradiation detection unit in the irradiation detection mode. A radiographic image detection device.
(3) In the radiological image detection apparatus according to (2), the irradiation detection unit includes a storage unit that stores a signal value corresponding to an input electrical signal, and is stored in the storage unit A radiographic image detection apparatus that detects radiation irradiation based on a difference between a signal value and a signal value corresponding to an input electrical signal.
(4) In the radiological image detection apparatus according to (2) or (3), the image receiving unit includes a plurality of irradiation detection pixels, and the irradiation detection unit is provided for each of the irradiation detection pixels. Alternatively, a second amplifier unit that is provided for each irradiation detection pixel group including a plurality of irradiation detection pixels and includes a plurality of amplifiers that amplify electric signals output from the corresponding irradiation detection pixels or irradiation detection pixel groups. And a determination unit that detects radiation irradiation based on the electric signal amplified by the second amplifier unit, wherein the second amplifier unit operates independently of each of the plurality of amplifiers. Radiation image detection that supplies operating power to a part of the amplifiers that are sequentially selected from the plurality of amplifiers for each operation period in the periodic operation of the irradiation detection unit. apparatus.
(5) The radiological image detection apparatus according to any one of (2) to (4), wherein the control unit is configured to detect radiation irradiation by the irradiation detection unit in the irradiation detection mode. , And periodically operating the first amplifier unit by supplying operation power to the first amplifier unit so that the reset operation for extracting the charges generated in the image detection pixels is performed periodically. Radiation image detection device.
(6) The radiological image detection apparatus according to (5), wherein an operation cycle of the irradiation detection unit is shorter than a cycle of a reset operation of each of the image detection pixels.
(7) The radiological image detection apparatus according to any one of (1) to (6), wherein the control unit operates on the irradiation detection unit after radiation irradiation is detected by the irradiation detection unit. A radiological image detection apparatus that stops supplying power.
(8) The portable radiographic image detection apparatus according to any one of (1) to (7) above.
(9) The radiographic image detection apparatus according to any one of (1) to (8) above and a console to which imaging information is input, and the control unit finishes inputting the imaging condition information in the console A radiation imaging system in which the performed timing is the start timing of the irradiation detection mode.

DESCRIPTION OF SYMBOLS 1 X-ray imaging system 2 X-ray imaging apparatus 3 Console 11 X-ray source 12 Electronic cassette 40 Image receiving part 41 Pixel 41a Image detection pixel 41b Irradiation detection pixel 51 Image data generation part 53 Irradiation detection part 60 Amplifier part (1st amplifier) Part)
61 Data processing unit 70 Amplifier unit (second amplifier unit)
71 Judgment part

And an image receiving section having a two-dimensional array of image detection pixels and at least one irradiation detection pixels for generating charges by the radiation is irradiated, based on the electric signal output from each image detection pixel sending the image data generating unit that generates image data, and the irradiation detecting section for detecting irradiation of radiation based on the electrical signal output from the respective irradiation detection pixels, the image data generated by the image data generating unit a communication unit that includes a control unit having a plurality of control modes including a radiation detection mode and a standby mode performing imaging mode and radiation detection for performing image data generation, the control section, at the irradiation detection mode When radiation irradiation is detected by the irradiation detection unit, the mode shifts to the imaging mode, and the image data generation unit is in the imaging mode. Thus the image data generated is transmitted by the communication unit the irradiation proceeds to the detection mode, the radiation image detecting apparatus to be migrated from the migration to the irradiation detection mode to the standby mode after a predetermined time has elapsed.

Claims (9)

An image receiving unit having a two-dimensional array of a plurality of image detection pixels and at least one irradiation detection pixel that generate a charge when irradiated with radiation; and
An image data generation unit that generates image data based on an electrical signal output from each of the image detection pixels;
An irradiation detection unit that detects irradiation of radiation based on an electrical signal output from each of the irradiation detection pixels;
A control unit having a plurality of control modes including an imaging mode for generating image data and an irradiation detection mode for detecting irradiation of radiation;
With
The image data generation unit includes a first amplifier unit that amplifies an electric signal output from each of the image detection pixels, a data processing unit that converts the electric signal amplified by the first amplifier unit into image data, And is configured to be able to supply operating power independently to each of the first amplifier unit and the data processing unit,
The control unit stops supply of operating power to the data processing unit until radiation irradiation is detected by the irradiation detection unit in the irradiation detection mode, and radiation irradiation is performed by the irradiation detection unit. When detected, the radiographic image detection apparatus that shifts to the imaging mode and starts supplying operating power to the data processing unit. The radiological image detection apparatus according to claim 1,
In the irradiation detection mode, the control unit periodically supplies operating power to the irradiation detection unit to periodically operate the irradiation detection unit. The radiological image detection apparatus according to claim 2,
The irradiation detection unit includes a storage unit that stores a signal value corresponding to an input electric signal, and the signal value stored in the storage unit and a signal value corresponding to the input electric signal A radiological image detection apparatus that detects radiation irradiation based on the difference. The radiological image detection apparatus according to claim 2 or 3,
The image receiving unit has a plurality of irradiation detection pixels,
The irradiation detection unit is provided for each irradiation detection pixel or each irradiation detection pixel group including a plurality of the irradiation detection pixels, and is output from a corresponding irradiation detection pixel or irradiation detection pixel group. A second amplifier unit having a plurality of amplifiers for amplifying the signal, and a determination unit for detecting radiation irradiation based on the electrical signal amplified by the second amplifier unit,
The second amplifier unit is configured to be able to supply operating power to each of the plurality of amplifiers independently.
The said control part is a radiographic image detection apparatus which supplies operating electric power to the one part amplifier selected in order from these amplifiers for every operation | movement period in the periodic operation | movement of the said irradiation detection part. The radiological image detection apparatus according to any one of claims 2 to 4,
In the irradiation detection mode, the control unit periodically performs a reset operation for extracting charges generated in the image detection pixels until radiation irradiation is detected by the irradiation detection unit. A radiological image detection apparatus for periodically operating the first amplifier section by periodically supplying operating power to the first amplifier section. The radiological image detection apparatus according to claim 5,
The radiation image detection device, wherein an operation cycle of the irradiation detection unit is shorter than a cycle of a reset operation of each image detection pixel. The radiological image detection apparatus according to any one of claims 1 to 6,
The said control part is a radiographic image detection apparatus which stops supply of the operating electric power to the said irradiation detection part, after the irradiation detection by the said irradiation detection part is detected.   The portable radiographic image detection apparatus according to any one of claims 1 to 7. The radiological image detection apparatus according to any one of claims 1 to 8,
A console where shooting information is entered,
With
The said control part is a radiography system which makes the timing which the input of the said imaging condition information completed in the said console makes the timing of the start of the said irradiation detection mode.

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