JP4809999B2 - Radiation imaging apparatus and radiation imaging system - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a radiation imaging apparatus and a radiation imaging system, and in particular, a radiation generation source that emits radiation to a subject, a converter that converts radiation from the subject into an optical signal, and imaging that converts the optical signal into an electrical signal. The present invention relates to a radiation imaging apparatus and a radiation imaging system including an element.
[0002]
[Prior art]
In recent years, in the medical field as well as in other fields, digitization and digitization have progressed, and development of an X-ray imaging apparatus that can be digitized immediately after photographing instead of X-ray photography using a film is proceeding. Further, it is desired to detect not only a still image but also an X-ray image of a moving subject such as a heart in an X-ray imaging apparatus.
[0003]
As a conventional X-ray imaging apparatus, for example, a combination of an image intensity fire (I.I) and a CCD is used. However, a good image cannot be obtained due to a problem of contrast reduction due to image distortion or halation. In addition, it is difficult to use due to its large shape and heavy weight, and it was difficult to use especially during operation.
[0004]
Instead of this, a thin and large-area X-ray imaging apparatus in which a scintillator such as CsI is bonded to an imaging element has been studied. As an image sensor, a CCD sensor or a CMOS sensor is generally known.
[0005]
When a CCD sensor is used as an image sensor, the CCD, in principle, requires a current consumption proportional to the area and is not suitable for large area, and the power must be turned on for a long time, especially when taking a video. Therefore, it is difficult to realize a large area X-ray imaging apparatus.
[0006]
[Problems to be solved by the invention]
FIG. 13 shows a configuration diagram of a pixel portion constituting each pixel of a conventional CMOS image sensor. 401 is a photodiode (PD) that performs photoelectric conversion, 404 is a MOS transistor (pixel reset switch) that resets charges accumulated in the photodiode 401, and 406 is a vertical transfer line (output line) 505 that transfers charges generated by the photodiode. An amplifying MOS transistor (pixel amplifier) that functions as a source follower amplifier that transfers to the. A row selection MOS transistor 405 performs row selection of a pixel from which an imaging signal is read (row selection switch). The column selection MOS transistor 506 selects the image pickup signal read by row selection for each column (column selection switch). An amplifier 508 is provided as a buffer for supplying the imaging signal read out by column selection to the outside of the imaging device. The amplification MOS transistor 406 and the row selection MOS transistor 405 constitute output means.
[0007]
Note that the gate of the pixel reset switch 404 is connected to the reset pulse 503 from the vertical shift register 501, and the gate of the row selection switch 405 is connected to the row selection pulse 504 from the vertical shift register 501 serving as a vertical scanning circuit. A gate 506 is connected to the horizontal shift register 507.
[0008]
Next, the drive timing of the image sensor will be described with reference to FIG.
X-rays are continuously irradiated.
[0009]
First, after an exposure time for subject imaging, the row selection pulse 504-1 goes to a high level at T4 to turn on the row selection MOS transistor 405 group in the corresponding row, and the vertical transfer line 505 via the amplification amplifier 406. The imaging signal is read out. The image signals for one row read out in this way are read out of the image sensor via the amplifier 508 when the column selection pulses 509-1, 509-2, and 509-3 are sequentially turned on by the horizontal shift register 507. It is. Thereafter, at T1, the reset pulse 503-1 goes to a high level and the reset MOS transistor 404 group in the first row is turned on, whereby the charge accumulated in the photodiode 401 in the corresponding row is reset to a predetermined level. . The exposure period of the first row is from the completion of reset pulse 503-1 at the previous reading (not shown) to the completion T4 of row selection pulse 504-1 (from the completion T1 of reset pulse 503-1 at reading to the row. The period of time until the completion T4 'of the selection pulse 504-1).
[0010]
Reading of the imaging signal to the vertical transfer line 505 by the row selection pulse 504-2 of the next row must be performed after the column selection pulse 509 of the previous row is completed, that is, after T7. The exposure period of the second row is from the completion of the reset pulse 503-2 at the previous reading (not shown) to the completion of the row selection pulse 504-2 at T5 (the row from the completion T2 of the reset pulse 503-2 at the time of reading). The period of time until the completion T5 'of the selection pulse 504-1). For this reason, the photodiodes in the second row are reset when the reset pulse 503-2 is set to the high level and the reset MOS transistor group is turned on at T2 delayed from the reset pulse at T1 in the previous row. The read sequence after reset is the same as in the first row.
[0011]
The pixel reset in the third row is further performed by a reset pulse 503-3 from T3 delayed from T2. The exposure period in this case is from the completion T3 ″ of the reset pulse 503-3 to the completion of the row selection pulse 504-3 at T6.
[0012]
Therefore, the exposure of the image by this image sensor is delayed for each line. As a result, the moving subject has a deviation from the real time.
[0013]
Further, in order to explain the time shift of the moving image between the image sensors in the line sequential scanning, FIG. 15 shows an example in which a large plate is configured using nine image sensors.
[0014]
Here, reference numerals 100, 110, 120, 130, 140, 150, 160, 170, and 180 are image sensors that perform line-sequential scanning with the above-described configuration. 101-103 are scanning lines of the image sensor 100, 111-113 are scanning lines of the image sensor 110, 121-123 are scanning lines of the image sensor 120, 131-133 are scanning lines of the image sensor 130, and 141-143 are image sensors. 140 scanning lines, 151 to 153 are scanning lines of the imaging device 150, 161 to 163 are scanning lines of the imaging device 160, 171 to 173 are scanning lines of the imaging device 170, and 181 to 183 are scanning lines of the imaging device 180. ing. Note that the arrow indicates the reading direction of the imaging signal. Note that nine exposures for imaging are simultaneously performed from the first scanning line (corresponding to the scanning line 101 in the imaging device 100) of the imaging devices 100, 110, 120, 130, 140, 150, 160, 170, and 180. Be started.
[0015]
In scanning within these image sensors, as described above, a shift in imaging exposure timing occurs between the imaging exposure time of the first scanning line and the last scanning line. For example, in the imaging device 100, the imaging exposure timing of the scanning line 102 is delayed from the imaging exposure timing of the scanning line 101, and the imaging exposure timing of the scanning line 103 is delayed by about one frame time from the imaging exposure timing of the scanning line 101. Therefore, an exposure time shift that occurs between scanning lines in an image sensor that captures a moving subject affects the image.
[0016]
Further, since the scanning line 131 of the imaging device 130 having the above-described configuration and the scanning line 103 of the imaging device 100 have a difference of about one frame time, a bonded portion between the imaging devices 100 and 130 when a moving subject is imaged. The connection of the moving images becomes unnatural. Of course, the moving image is unnatural even at the boundary between the image pickup device 130 and the image pickup device 160, the image pickup device 110 and the image pickup device 140, the image pickup device 140 and the image pickup device 170, the image pickup device 120 and the image pickup device 150, and the image pickup device 150 and the image pickup device 180. It becomes.
[0017]
As described above, a CMOS image sensor that can be enlarged by pasting usually causes a time shift with respect to a moving subject because line sequential scanning is performed. This time shift is particularly noticeable at the boundary between the image sensors.
[0018]
[Means for Solving the Problems]
  The radiation imaging apparatus of the present invention includes a radiation generation source that intermittently emits radiation to a subject in a pulse shape, a scintillator that converts radiation from the subject into light, and converts the light into an electrical signal to convert the electrical signal An image sensor that outputs a signal based on the image sensor, wherein the image sensor is configured by arranging a plurality of pixels in rows and columns, and outputting the signals from the pixels to an output line arranged for each column. In the radiation imaging apparatus, the pixel includes the pixelConverted by scintillatorthe lightElectricA photodiode that converts the signal into a power signal, a reset transistor that resets the photodiode, andConverted by photodiodeAn amplification transistor for amplifying an electric signal, a control transistor for controlling connection and disconnection of the amplification transistor to a constant current source, and one end coupled to the amplification transistor and the other end coupled to a transistor for controlling supply of a clamp potential A clamp circuit for removing noise generated when the reset transistor resets the photodiode with a clamped capacitor;By turning on the first transistor having a first transistor and a first capacitor, the amplification transistorAmplifiedElectricQi signalIn the first capacityTo accumulateThe first1 sample hold circuit;By turning on the second transistor having a second transistor and a second capacitorThe clamp potentialAn electrical signal based on the second capacitanceTo accumulateThe first2 sample hold circuit, and the clamp potential is simultaneously applied to the second capacitor in all pixels.Accumulated electrical signal based onIn the period from when the amplification transistor by the control transistor is disconnected from the constant current source until the reset of the photodiodes of all the pixels by the reset transistor is started collectively. Emits the pulsed radiation.
[0021]
【Example】
Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. In the following description, a radiation imaging apparatus that detects radiation such as X-rays will be described.
[0022]
(First embodiment)
FIG. 1 is a block diagram showing a configuration of a radiation imaging apparatus according to the present invention. FIG. 2 is a block diagram showing a configuration of an image sensor in which peripheral circuits such as horizontal and vertical shift registers are formed in an effective pixel area. FIG. 3 is a diagram showing a layout relationship among pixels in the effective area, a shift register, a protection circuit, an external terminal, and the like. FIG. 4 is a diagram for explaining an image pickup apparatus in which nine image pickup elements are bonded, and FIG. 5 is a diagram showing drive timing of the pixel portion.
[0023]
As shown in FIG. 1, when a moving image of the subject 2 is obtained, X-rays are generated from the pulse X-ray generator 1, and the X-rays transmitted through the subject 2 are converted into light such as visible light by the scintillator 3. . This light is converted into an electric signal by the image pickup apparatus 4 constituted by five or more image pickup elements. The analog electrical signal is converted into a digital signal by the A / D converter 5 and then stored in the storage device 6 for storing a plurality of moving images. Note that a transparent image processing unit 10 and a D / A converter 11 are used to display an image. Specifically, real-time transmission data after A / D conversion or post-storage transmission data is subjected to image processing by the transmission image processing unit 10 and then converted into digital / analog signals and displayed on the transmission image monitor 12. The controller 7 controls the pulse X-ray generator 1, each image sensor of the imaging device 4, and the transmission image processing device 10. For the input operation to the controller 7, an operating device 9 and an operation monitor 8 are used. In addition, the individual image sensor which comprises the imaging device of this invention is the same as the structure shown in FIG.
[0024]
As shown in the timing chart of FIG. 5, the X-ray generator 1 emits X-rays intermittently in a pulsed manner, and signal charge is completely accumulated in a photodiode (PD) serving as a photoelectric conversion means after pixel reset. The pulsed X-ray of the period set by the controller 7 is generated until the period becomes. The timing chart shown in FIG. 5 is the same as the timing chart shown in FIG. 14 except that the timing of X-ray generation is different.
[0025]
FIG. 2 shows an example in which one image sensor (entire pixel) 602 is taken out from the currently mainstream 8-inch wafer 600. A 138 mm □ CMOS type image pickup device substrate is formed by a single process using a CMOS process. In a medical X-ray imaging apparatus, the pixel size may be as large as about 100 μm □ to 200 μm □. As shown in FIG. 2, a vertical shift register 601 and a horizontal shift register 607 are formed in the image sensor, and an external terminal (electrode pad) is provided at the end of the element near the horizontal shift register 607. This electrode pad is used for connection with a flexible substrate or the like.
[0026]
FIG. 3 is a plan view showing a layout relationship among pixels, shift registers, protection circuits, external terminals, and the like in the effective area of the image sensor shown in FIG. As shown in FIG. 3, a plurality of pixels 2101 are arranged two-dimensionally in the vertical and horizontal directions in the image sensor. The vertical shift register 2102 and the horizontal shift register 2103 are arranged in the effective area of the image sensor, and the area of the pixels of one vertical and horizontal line is small so that the vertical shift register 2102 and the horizontal shift register 2103 are within one pixel pitch. Has been. A selection transistor 2104 for selecting a vertical output line is provided above the horizontal shift register 2103, and an external terminal (electrode pad) 2105 and a protection circuit 2107 are provided at an element end near the horizontal shift register 2103. The external terminal 2105 is electrically connected by a bump 2106.
[0027]
FIG. 4 shows an example in which a 414 mm □ large-area radiation moving image pickup apparatus is configured by bonding nine 138 mm □ image pickup devices shown in FIG. 2 together. Nine image sensors 602 are bonded on the base, and a large-screen image pickup apparatus is configured as a whole.
[0028]
In the radiographic image capturing apparatus having the above-described configuration, the light receiving areas are uniformly sized and the centroids are arranged at an equal pitch within each image sensor and between the image sensors. Since there is no variation in sensitivity between image sensors and within the image sensor, or variations in the center of gravity of the light receiving area, a substantially seamless image can be obtained even with a tiled configuration. In addition, since pixels are arranged in the end region of the image sensor and no dead space is generated by a shift register or the like, the entire surface of the image sensor becomes an effective region.
[0029]
According to the present embodiment, by generating X-rays in a pulsed manner, the image of each row in one frame becomes X shown in FIG.₁In this period, each pixel row of the image sensor is exposed simultaneously. Further, there is no image displacement even in an apparatus in which a plurality of sheets are bonded. Furthermore, the moving image can be observed and at the same time, there is little blur when one frame and one frame are observed. Therefore, a good image can be obtained even if the heart is photographed.
[0030]
(Second embodiment)
FIG. 6 is a diagram showing the driving timing of the pixel unit of the radiation imaging apparatus according to the second embodiment of the present invention.
[0031]
As shown in FIG. 6, the resetting of each pixel is performed collectively in accordance with the reset timing of the last row, and then X-rays are generated in a pulse shape. By such an operation, the dark current accumulation of the sensor becomes a period of I1, I2, and I3, the average dark current accumulation is reduced, and the shot noise accompanying the dark current is small and good.
[0032]
(Third embodiment)
FIG. 7 is a circuit diagram showing another pixel configuration of the image sensor that constitutes the radiation imaging apparatus of the present invention.
[0033]
In the pixel shown in FIG. 7, kTC noise (reset noise) correction in the photoelectric conversion unit is performed in the pixel, and sensitivity switching means is provided in the pixel, so that still image shooting and high-speed movie shooting can be switched between modes. Realized. Further, a sample hold circuit is provided in the pixel in order to store the signal and read out the signal independently of the exposure operation.
[0034]
The irradiation X-ray dose during movie shooting is about 1/100 that during still image shooting, and it is desirable to reduce the capacity of the photodiode in order to obtain high sensitivity during movie shooting. Therefore, it is desirable to increase the capacity. In this embodiment, a changeover switch 41 is provided so that a capacitive element 40 for expanding the dynamic range can be added in parallel with the photodiode so that the sensitivity can be switched. Further, by providing a clamp circuit having a clamp capacitor 49 and a clamp switch 47, kTC noise generated in the photoelectric conversion unit is removed. Further, in order to store the signal and read the signal independently of the exposure operation, an optical signal storage sample and hold circuit (capacitor 53 and MOS transistor 52) and a noise signal storage sample and hold circuit (capacitor 54 and MOS transistor 57). ).
[0035]
That is, as shown in FIG. 7, the pixel of this embodiment includes a photodiode 44 as a photoelectric conversion element, a capacitor element 40 for changing sensitivity, a switch MOS transistor 41 for switching sensitivity, and a reset for resetting the photodiode 44. A MOS transistor 43, a source follower MOS transistor 46 for amplifying an image pickup signal from the photodiode 44, a MOS transistor 45 for turning on and off a constant current source to the amplification transistor 46, and a constant current source 48 are provided. This pixel also includes a capacitor 49 for canceling kTC noise generated when resetting the phototransistor 44 and clamping the imaging signal with a constant voltage, a MOS transistor 47 for turning on / off the clamp potential, a source follower MOS transistor 50, a source The MOS transistor 51 for turning on and off the constant current source to the follower MOS transistor 50, the constant current source 56, the capacitor 53 for storing the imaging signal, the MOS transistor 52 for turning on and off the imaging signal to the capacitor 53, and the imaging signal A source follower MOS transistor 58 that outputs to a vertical line, a select MOS transistor 59 for turning on / off the output of the source follower MOS transistor 58, a constant current source 62 used for this output, a capacitor 57 for storing a clamp potential, Capacity 57 hex MOS transistor 54 for turning on / off the amplifier potential, source follower MOS transistor 60 for outputting the clamp potential to the vertical line, selection MOS transistor 61 for turning on / off the output of the source follower to the vertical line, and used for this output A constant current source 63 is provided.
[0036]
Next, the drive timing of the image sensor will be described with reference to FIG.
[0037]
In this embodiment, the capacitive element 40 is connected or disconnected by the gate signal SSW of the MOS transistor 41, and the sensitivity is switched by adding or disconnecting the capacitance of the capacitive element 40 to the photodiode 44. As described above, in the still image shooting mode, the MOS transistor 41 is turned on to add capacitance, and in the high-speed moving image shooting mode, the MOS transistor 41 is turned off to disconnect the capacitance.
[0038]
First, the signals EN and CHG are set to the high level to turn on the constant current sources to the amplification transistors 46 and 50, and the signal RS is set to the high level to reset the charge of the photodiode 44 to the potential 64. Next, the signal RC is set to the high level and the MOS transistor 47 is also turned on, so that one end of the clamp capacitor 49 is substantially biased to the potential 66. In this way, kTC noise (reset noise) generated by resetting the charge of the photodiode 44 is accumulated in the clamp capacitor 49. When the signal TN is set to the high level, the clamp potential of the clamp capacitor 49 is accumulated in the capacitor 57. The above is the noise signal accumulation operation.
[0039]
Next, exposure is performed by X-ray pulse exposure, and photoelectric charges are accumulated in the photodiode 44 (moving image capturing mode) or in the photodiode 44 and the capacitor 40 (still image capturing mode) (this is the exposure operation). .) Thereafter, when the signal EN is set to the high level, the potential at one end of the clamp capacitor 49 varies by a signal component corresponding to the photocharge. That is, since the kTC noise component is accumulated in the clamp capacitor 49, the potential at one end of the clamp capacitor 49 is changed by the potential obtained by subtracting the kTC noise component from the imaging signal including the kTC noise component. In order to read out the imaging signal with the kTC noise canceled, the imaging signal (optical signal) with the kTC noise canceled is accumulated in the capacitor 52 by setting the signal CHG and the signal TS to a high level. The above is the optical signal accumulation operation.
[0040]
The above series of operations is repeated. Here, the exposure time of the image sensor is after the clamp potential is transferred to the capacitor 57, that is, from when the signal EN becomes low level until the signal RS becomes high level and the reset MOS transistor 43 is turned on. . Therefore, during this period, the X-ray exposure time can be determined to be longer or shorter. Note that signal readout is performed during the exposure possible period. That is, by setting the signal SEL to a high level for each row and setting the signal SELH (not shown) to a high level for each column within the exposure possible period, a noise signal and an optical signal are output. By subtracting the noise signal from the optical signal with a subtracting amplifier (not shown), it is possible to remove the thermal noise, 1 / f noise, temperature difference, and fixed pattern noise (FPN) due to process variations in the source follower amplifier.
[0041]
In the imaging operation described above, all the pixels are reset simultaneously by setting the signal RS to the high level and reading the pixel (light) signal to the high level. Further, the output of the noise signal and the optical signal and the pulsed exposure are performed in parallel, and the frame speed can be increased. By increasing the frame speed, dark accumulation is reduced and noise can be reduced.
[0042]
Compared to the second embodiment, the dark accumulation time is constant, the image quality is uniform over the entire surface, and a good image can be obtained. Further, the X-ray irradiation possible period can be made long and the control becomes simple. Also, even if the X-ray pulse is lengthened to some extent, the frame speed does not decrease.
[0043]
As described above, according to the present imaging apparatus, all of the imaging surfaces of the imaging elements 70 to 78 shown in FIG. 10 can be exposed simultaneously, and the moving image scanning line and the shift at the imaging element connecting portion, which have been conventional problems, are detected. However, it is also eliminated when the CMOS image sensor is bonded.
[0044]
(Fourth embodiment)
FIG. 9 is a diagram showing another driving timing of the pixel portion of the radiation imaging apparatus of the present invention.
[0045]
As shown in FIG. 9, in this embodiment, the pixel reset pulse RS is added immediately before the X-ray pulse. In this embodiment, dark accumulation can be further shortened.
[0046]
Next, a configuration of the imaging unit of the radiation imaging apparatus according to the present invention and a specific example of an X-ray detection system using the radiation imaging apparatus will be described.
[0047]
FIG. 11 is a cross-sectional view showing the configuration of the imaging unit of the radiation imaging apparatus according to the present invention. As shown in FIG. 11, a plurality of imaging elements 701 are arranged on a base substrate 704, and incident radiation 703 such as X-rays is light in a wavelength region detectable by the imaging element 701 with a scintillator such as a phosphor 702, For example, the image sensor 701 detects light corresponding to incident radiation that is converted into visible light or infrared light. Reference numeral 705 denotes a flexible substrate that transfers a signal from the image sensor to the base substrate 704.
[0048]
FIG. 12 shows an application example of the radiation imaging apparatus according to the present invention to an X-ray diagnostic system.
[0049]
The X-ray 6060 generated by the X-ray tube 6050 passes through the chest 6062 of the patient or subject 6061 and enters the imaging device 6040 having a scintillator mounted thereon. This incident X-ray includes information inside the body of the patient 6061. The scintillator emits light in response to the incidence of X-rays, and this is photoelectrically converted to obtain electrical information. This information is digitally converted and image-processed by an image processor 6070 serving as a signal processing means, and can be observed on a display 6080 in a control room.
[0050]
Further, this information can be transferred to a remote place by transmission processing means such as a telephone line 6090, and can be displayed on a display 6081 such as a doctor room in another place or stored in a recording means such as an optical disc. It is also possible to do. Further, it can be recorded on a recording means such as a film 6110 by the film processor 6100.
[0051]
【The invention's effect】
  As described above, according to the present invention, it is possible to pick up an image pickup device with less distortion and to pick up a moving image within each image pickup device and between the image pickup devices without time lag.In addition, the frame speed can be increased, dark accumulation is reduced, and noise can be reduced. Also, the dark accumulation time is constant, the image quality is uniform throughout, and a good image can be obtained. Moreover, the radiation irradiation possible period can be made long, and the control becomes simple. Furthermore, even if the radiation pulse is lengthened to some extent, the frame speed does not decrease.
[Brief description of the drawings]
FIG. 1 is a block diagram showing the configuration of a first embodiment of a radiation imaging apparatus according to the present invention.
FIG. 2 is a block diagram showing a configuration of an image sensor in which peripheral circuits such as horizontal and vertical shift registers are formed in an effective pixel area.
FIG. 3 is a diagram illustrating a layout relationship among pixels in an effective area, a shift register, a protection circuit, an external terminal, and the like.
FIG. 4 is a diagram for explaining an image pickup apparatus in which nine image pickup elements are bonded together.
FIG. 5 is a diagram illustrating driving timing of a pixel portion.
FIG. 6 is a diagram showing the drive timing of the pixel unit of the second embodiment of the radiation imaging apparatus according to the present invention.
FIG. 7 is a diagram showing a configuration of a CMOS image sensor capable of batch exposure used in a third embodiment of the radiation imaging apparatus according to the present invention.
FIG. 8 is a cross-sectional view showing a configuration of a radiation imaging apparatus according to the present invention.
FIG. 9 is a diagram showing the drive timing of the pixel portion of the fourth embodiment of the radiation imaging apparatus according to the present invention.
FIG. 10 is a diagram for explaining an image pickup apparatus in which nine image pickup elements are bonded together.
FIG. 11 is a cross-sectional view illustrating a configuration of an imaging unit of the radiation imaging apparatus according to the present invention.
FIG. 12 is a diagram illustrating a specific example of an X-ray detection system using a radiation imaging apparatus according to the present invention.
FIG. 13 is a configuration diagram of a pixel portion constituting each pixel of a conventional CMOS image sensor.
FIG. 14 is a diagram illustrating drive timing of an image sensor.
FIG. 15 is a diagram of an imaging apparatus having a large size configuration using nine conventional CMOS imaging elements.
[Explanation of symbols]
1 Pulse X-ray generator
2 Subject
3 Scintillator
4 Imaging device
5 A / D converter
6 Storage device
8 Operation monitor
10 Transparent image processing unit
11 D / A converter
12 Transmission image monitor

Claims (6)

A radiation source that intermittently emits radiation to a subject in a pulse shape, a scintillator that converts radiation from the subject into light, and an image sensor that converts the light into an electrical signal and outputs a signal based on the electrical signal And
In the radiation imaging apparatus, the imaging element is configured by arranging a plurality of pixels in rows and columns, and outputting the signal from the pixels to an output line arranged for each column.
The pixel includes a photodiode which converts the light converted by the scintillator into electrical signals, a reset transistor for resetting the photodiode, an amplifying transistor for amplifying the electrical signal converted by the photodiode, the amplification The reset transistor having a control transistor for controlling connection and disconnection of a transistor to a constant current source, and a clamp capacitor having one end coupled to the amplification transistor and the other end coupled to a transistor for controlling supply of a clamp potential clamp circuit and, air electrostatic amplified by the amplifying transistor by turning on said first transistor having a first transistor and a first capacitor for but to remove noise generated when resetting the photodiode to accumulate a signal to the first capacitor First sample-and-hold circuit and a second sample for storing electrical signal based on the clamp potential to said second capacitor by turning on the second transistor and a second transistor and a second capacitor for A hold circuit,
After the electric signal based on the clamp potential is simultaneously accumulated in the second capacitor in all the pixels and the amplification transistor by the control transistor and the constant current source are disconnected, the phototransaction of all the pixels by the reset transistor is performed. The radiation imaging apparatus, wherein the radiation source emits the pulsed radiation during a period until the resetting of the diodes is started all at once. A scintillator that converts radiation that is intermittently emitted from a radiation source in a pulsed manner and transmitted through a subject into light, and an imaging device that converts the light into an electrical signal and outputs a signal based on the electrical signal;
In the radiation imaging apparatus, the imaging element is configured by arranging a plurality of pixels in rows and columns, and outputting the signal from the pixels to an output line arranged for each column.
The pixel includes a photodiode which converts the light converted by the scintillator into electrical signals, a reset transistor for resetting the photodiode, an amplifying transistor for amplifying the electrical signal converted by the photodiode, the amplification The reset transistor having a control transistor for controlling connection and disconnection of a transistor to a constant current source, and a clamp capacitor having one end coupled to the amplification transistor and the other end coupled to a transistor for controlling supply of a clamp potential clamp circuit and, air electrostatic amplified by the amplifying transistor by turning on said first transistor having a first transistor and a first capacitor for but to remove noise generated when resetting the photodiode to accumulate a signal to the first capacitor First sample-and-hold circuit and a second sample for storing electrical signal based on the clamp potential to said second capacitor by turning on the second transistor and a second transistor and a second capacitor for A hold circuit,
And reset by the reset transistor, the storage and the electric signal based on the clamp potential to the second capacitor, the accumulation of the first said amplified electrical signal to the capacitor, that each take place simultaneously in all pixels A radiation imaging apparatus. 3. The radiation imaging apparatus according to claim 1, wherein an electric signal based on the clamp potential is accumulated in the second capacitor, and the amplification transistor and the constant current source are disconnected from the control transistor. in the period leading up to the start in a batch reset the photodiodes of all pixels by the reset transistor, and an output from the first volume of the stored said amplified electrical signal to the first capacitor, the second radiation imaging apparatus which is characterized in that the output from the second capacity of the electric signal based on the clamp potential accumulated in the capacitor, the.   4. The radiation imaging apparatus according to claim 1, further comprising switch means for adding a capacitor in parallel to the photodiode.   5. The radiation imaging apparatus according to claim 1, wherein a plurality of the imaging elements are arranged side by side. A radiation imaging apparatus according to any one of claims 1 to 5, and signal processing means for processing a signal from the radiation imaging apparatus,
Recording means for recording a signal from the signal processing means;
Display means for displaying a signal from the signal processing means;
Transmission processing means for transmitting a signal from the signal processing means;
A radiation imaging system comprising:

Images