WO2011118286A1 - Dispositif et système de radiographie et procédé et système de génération d'une carte de pixels défectueux - Google Patents

Dispositif et système de radiographie et procédé et système de génération d'une carte de pixels défectueux Download PDF

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Publication number
WO2011118286A1
WO2011118286A1 PCT/JP2011/053189 JP2011053189W WO2011118286A1 WO 2011118286 A1 WO2011118286 A1 WO 2011118286A1 JP 2011053189 W JP2011053189 W JP 2011053189W WO 2011118286 A1 WO2011118286 A1 WO 2011118286A1
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Prior art keywords
radiation detection
image data
detection element
radiation
output abnormality
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PCT/JP2011/053189
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English (en)
Japanese (ja)
Inventor
剛 齋藤
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コニカミノルタエムジー株式会社
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Priority to JP2012506882A priority Critical patent/JP5761176B2/ja
Publication of WO2011118286A1 publication Critical patent/WO2011118286A1/fr

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    • G—PHYSICS
    • G03—PHOTOGRAPHY; CINEMATOGRAPHY; ANALOGOUS TECHNIQUES USING WAVES OTHER THAN OPTICAL WAVES; ELECTROGRAPHY; HOLOGRAPHY
    • G03B—APPARATUS OR ARRANGEMENTS FOR TAKING PHOTOGRAPHS OR FOR PROJECTING OR VIEWING THEM; APPARATUS OR ARRANGEMENTS EMPLOYING ANALOGOUS TECHNIQUES USING WAVES OTHER THAN OPTICAL WAVES; ACCESSORIES THEREFOR
    • G03B42/00—Obtaining records using waves other than optical waves; Visualisation of such records by using optical means
    • G03B42/02—Obtaining records using waves other than optical waves; Visualisation of such records by using optical means using X-rays
    • A—HUMAN NECESSITIES
    • A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
    • A61B—DIAGNOSIS; SURGERY; IDENTIFICATION
    • A61B6/00—Apparatus or devices for radiation diagnosis; Apparatus or devices for radiation diagnosis combined with radiation therapy equipment
    • A61B6/42—Arrangements for detecting radiation specially adapted for radiation diagnosis
    • A61B6/4208—Arrangements for detecting radiation specially adapted for radiation diagnosis characterised by using a particular type of detector
    • A61B6/4233—Arrangements for detecting radiation specially adapted for radiation diagnosis characterised by using a particular type of detector using matrix detectors
    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04N—PICTORIAL COMMUNICATION, e.g. TELEVISION
    • H04N23/00—Cameras or camera modules comprising electronic image sensors; Control thereof
    • H04N23/30—Cameras or camera modules comprising electronic image sensors; Control thereof for generating image signals from X-rays
    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04N—PICTORIAL COMMUNICATION, e.g. TELEVISION
    • H04N25/00—Circuitry of solid-state image sensors [SSIS]; Control thereof
    • H04N25/60—Noise processing, e.g. detecting, correcting, reducing or removing noise
    • H04N25/68—Noise processing, e.g. detecting, correcting, reducing or removing noise applied to defects
    • H04N25/69—SSIS comprising testing or correcting structures for circuits other than pixel cells

Definitions

  • the present invention relates to a radiographic image capturing apparatus, a radiographic image capturing system, a defective pixel map creating method for a radiographic image capturing apparatus, and a defective pixel map creating system for a radiographic image capturing apparatus capable of detecting a radiation detecting element exhibiting an abnormal detection value.
  • a radiographic image capturing apparatus a radiographic image capturing system, a defective pixel map creating method for a radiographic image capturing apparatus, and a defective pixel map creating system for a radiographic image capturing apparatus capable of detecting a radiation detecting element exhibiting an abnormal detection value.
  • a radiation image forming apparatus in which radiation detection elements called flat panel detectors (FPD) are two-dimensionally arranged is known.
  • FPD flat panel detectors
  • radiation energy is directly converted into charges using a photoconductive substance such as a-Se (amorphous selenium) as a radiation detection element, and the charges are arranged two-dimensionally.
  • a direct readout method that reads out electrical signals pixel by pixel using a signal readout switch element such as a TFT (Thin Film Transistor), or radiation energy is converted into light by a scintillator, etc., and this light is arranged two-dimensionally.
  • TFT Thintillator
  • radiation detection that outputs abnormal image data constantly or with a certain probability due to impurities mixed into the radiation detection element when forming the radiation detection element on the sensor panel.
  • An element may occur.
  • a radiographic image forming apparatus having a means for registering in (Patent Document 1) has been proposed.
  • the radiation detection element that outputs an output outside the range of m ⁇ 5 ⁇ is determined to be a defective radiation detection element.
  • the preliminary defect radiation detection element must be registered in the defect element map after it can be identified as a complete defect radiation detection element through repeated use.
  • even radiation detection elements that are not necessary are subject to interpolation processing, which may lead to a reduction in imaging accuracy.
  • an object of the present invention is to provide a radiographic image capturing apparatus, a radiographic image capturing system, a defective pixel map creating method, and a defective pixel map creating system that can more accurately identify a radiation detection element that is regarded as a defect. It is.
  • a radiographic imaging apparatus is divided by a plurality of scanning lines and a plurality of signal lines arranged so as to cross each other, and the plurality of scanning lines and a plurality of signal lines.
  • a plurality of radiation detection elements arranged two-dimensionally in each region, and a charge is read from the radiation detection element through the signal line, and the charge is converted into an electrical signal for each radiation detection element.
  • a readout circuit that outputs as data, and the readout circuit outputs actual image data as the data based on the charges accumulated by the respective radiation detection elements at a predetermined accumulation time at the time of imaging irradiated with radiation, and The readout circuit is based on charges accumulated in the same accumulation time as each of the radiation detection elements during the non-irradiation of the radiation.
  • a radiographic imaging apparatus comprising: control means for controlling to output dark image data for correcting the real image data; and communication means for transmitting / receiving data to / from an external device, wherein the control means Control is performed so that the readout circuit outputs dark image data for determining the output abnormality of the radiation detection element based on the charge accumulated in each radiation detection element during the non-irradiation with a longer accumulation time than during the imaging. It is characterized by doing.
  • the radiographic imaging system which is another side surface of this invention is a radiation provided with the radiographic imaging apparatus of Claim 1, and a console provided with the communication means which receives data between the said radiographic imaging apparatus.
  • the console has output abnormality determination means for determining an output abnormality of each radiation detection element from dark image data for determining the output abnormality, and any radiation detection element has an output abnormality.
  • a defect element map for storing the position of the radiation detection element to be output abnormal, and a registration means for registering the position of the radiation detection element determined to be output abnormal by the output abnormality determination means in the defect element map. It is characterized by.
  • a defective pixel map creating method for a radiographic image capturing apparatus, wherein a plurality of scanning lines and a plurality of signal lines arranged to intersect each other, and the plurality of scanning lines and a plurality of signals are arranged.
  • a detection unit including a plurality of radiation detection elements arranged in a two-dimensional manner in each region partitioned by lines, and reads out charges from the radiation detection elements through the signal lines, and electrically charges the charges for each of the radiation detection elements.
  • a radiographic imaging apparatus including a readout circuit that converts the signal into a signal and outputs the data, a defective pixel map that stores which radiation detection element has an output abnormality or the position of the radiation detection element to be output abnormal is created.
  • a method for creating a defective pixel map wherein charges are accumulated in each of the plurality of radiation detection elements and charges are read by the readout circuit. And after the aging step, each radiation detection element accumulates charges in a longer accumulation time than when photographing in a non-irradiated state, and determines an output abnormality of the radiation detection element from the accumulated charges.
  • a dark image data acquisition step for acquiring dark image data for the determination; a determination step for determining an output abnormality of each radiation detection element based on dark image data for an output abnormality determination of the radiation detection element;
  • a defective pixel map creation system for a radiographic imaging apparatus includes a plurality of scanning lines and a plurality of signal lines arranged to intersect each other, and the plurality of scanning lines and a plurality of signals.
  • a detection unit including a plurality of radiation detection elements arranged in a two-dimensional manner in each region partitioned by lines, and reads out charges from the radiation detection elements through the signal lines, and electrically charges the charges for each of the radiation detection elements.
  • a defective pixel map that stores which radiation detection element has an output abnormality or a position of the radiation detection element that causes an output abnormality is created.
  • a defective pixel map creation system for creating a defective pixel map
  • charge accumulation and reading of each of the plurality of radiation detection elements are performed.
  • An aging control unit that repeatedly reads out charges by the extraction circuit, and each of the radiation detection elements that has repeatedly performed charge accumulation and charge read-out has a longer accumulation time than that during imaging in a non-radiation state.
  • a dark image data acquisition control unit for acquiring dark image data for determining output abnormality of the radiation detection element from the stored charge, and based on dark image data for determining output abnormality of the radiation detection element And a defect that creates the defective pixel map in which the radiation detection element that causes the output abnormality is registered based on the determination unit that determines the output abnormality of the radiation detection element and the determination of the output abnormality of the radiation detection element. And a pixel map creating unit.
  • the radiographic image capturing apparatus and the radiographic image capturing system according to the present invention are configured such that the control unit of the radiographic image capturing apparatus has a longer accumulation time for each radiation detection element when no radiation is applied (so-called dark charge acquisition time) than when imaging. Control is performed so as to acquire dark image data for determining an output abnormality of the radiation detection element from the readout circuit based on the electric charge accumulated in step.
  • the charge accumulation time of each radiation detection element at the time of dark image data acquisition is made longer, the value of the distribution of the dark image data of the normal radiation detection element is concentrated and the dark image by the radiation detection element of abnormal output The difference from the data can be widened according to the accumulation time.
  • an abnormal value becomes obvious, it becomes easy to discriminate between a normal value and an abnormal value, and the threshold value can also easily take an appropriate value.
  • the threshold value can also easily take an appropriate value.
  • a radiation detection element that outputs dark image data close to a normal value while causing an abnormality can be separated and distinguished from a normal radiation detection element. For example, a radiation detection element that was originally normal can be identified. Even if it is gradually becoming abnormal, it can be determined as abnormal at an early stage, and it is possible to reduce the frequency of maintenance for monitoring the radiation detecting element with abnormal output.
  • the determination accuracy improvement by the dark image data for the output abnormality determination obtained based on the charge accumulated in the accumulation time longer than that at the time of the imaging is improved. It is possible to obtain the effect.
  • the defective pixel map creation method and the defective pixel map creation system of the radiographic imaging apparatus since the aging is performed on the radiation detection element and the readout circuit, a weak output abnormality occurs. It is possible to advance an abnormal state for a radiation detection element that is likely to cause an output abnormality later, such that it is not determined, and to detect it as an abnormal output in subsequent determination.
  • radiation detectors that become abnormal after the repeated use can be found at an early stage, and radiation detectors that output abnormalities can be registered in the defective pixel map, so the use of the radiographic imaging device is started.
  • the number of radiation detecting elements that will cause an abnormality later is reduced, and the maintenance burden can be reduced.
  • FIG. 2 is a cross-sectional view taken along line AA in FIG. It is a top view which shows the structure of the board
  • FIG. 5 is a cross-sectional view taken along line BB in FIG. 4. It is a side view explaining the board
  • FIG. 6 is a diagram showing a correspondence relationship between dark image data and the frequency when dark image data is acquired with the same charge accumulation time of each radiation detection element as in normal imaging.
  • FIG. 6 is a diagram showing a correspondence relationship between dark image data and the frequency when dark image data is acquired with the charge accumulation time of each radiation detection element set longer than that in normal imaging.
  • It is a flowchart shown about the processing content of the image display control of a console.
  • It is a conceptual diagram which shows the content of the interpolation of the image data based on the output of the radiation detection element of an output abnormality.
  • It is a block diagram which shows the structure of the other example of a radiographic imaging apparatus. It is a figure which shows the whole structure of a defective pixel map production system.
  • the radiographic imaging device is a so-called indirect radiographic imaging device that includes a scintillator or the like and converts the irradiated radiation into electromagnetic waves of other wavelengths such as visible light to obtain an electrical signal.
  • the present invention can also be applied to a direct radiographic imaging apparatus.
  • the radiographic image capturing apparatus is portable will be described, the present invention is also applicable to a radiographic image capturing apparatus formed integrally with a support base or the like.
  • FIG. 1 is an external perspective view of the radiographic image capturing apparatus according to the present embodiment
  • FIG. 2 is a cross-sectional view taken along the line AA in FIG.
  • the radiographic image capturing apparatus 1 according to the present embodiment is configured by housing a scintillator 3, a substrate 4, and the like inside a housing 2.
  • the housing 2 is formed of a material such as a carbon plate or plastic that transmits at least the radiation incident surface R. 1 and 2 show a case where the housing 2 is a so-called lunch box type formed by the frame plate 2A and the back plate 2B, but the shape of the housing 2 is not limited to this. . It is also possible to use a so-called monocoque type in which the housing 2 is integrally formed in a rectangular tube shape.
  • the side surface of the housing 2 is opened and closed for replacement of a power switch 36, an indicator 37 composed of LEDs and the like, and a battery 41 (not shown) (see FIG. 7 described later).
  • a possible lid member 38 and the like are arranged.
  • an antenna device that is a communication unit for wirelessly transferring image data G (described later) to an external device such as a console 58 (described later) illustrated in FIG. 39 is embedded. It is also possible to transfer the image data G to an external device in a wired manner. In that case, for example, as a communication means, a connection terminal or the like for connection by inserting a cable or the like is used as radiation. It is provided on the side surface of the image capturing apparatus 1 or the like.
  • a base 31 is disposed inside the housing 2 via a thin lead plate or the like (not shown) on the lower side of the substrate 4.
  • the disposed PCB substrate 33, the buffer member 34, and the like are attached.
  • a glass substrate 35 for protecting the substrate 4 and the radiation incident surface R of the scintillator 3 is disposed.
  • the scintillator 3 is affixed to a detection part P (described later) of the substrate 4.
  • the scintillator 3 is, for example, a phosphor whose main component is converted into an electromagnetic wave having a wavelength of 300 to 800 nm, that is, an electromagnetic wave centered on visible light when it receives radiation, and that is output.
  • the substrate 4 is formed of a glass substrate. As shown in FIG. 3, a plurality of scanning lines 5 and a plurality of signal lines are provided on a surface 4 a of the substrate 4 facing the scintillator 3. 6 are arranged so as to cross each other. In each small region r defined by the plurality of scanning lines 5 and the plurality of signal lines 6 on the surface 4 a of the substrate 4, radiation detection elements 7 are respectively provided.
  • the region is a detection unit P.
  • a photodiode is used as the radiation detection element 7, but other than this, for example, a phototransistor or the like can also be used.
  • Each radiation detection element 7 is connected to the source electrode 8s of the TFT 8 serving as a switching element, as shown in the enlarged views of FIGS.
  • the drain electrode 8 d of the TFT 8 is connected to the signal line 6.
  • the TFT 8 is turned on when an ON voltage is applied to the connected scanning line 5 and applied to the gate electrode 8g by a scanning driving means 15 (see FIG. 7), which will be described later, and the radiation detection element 7 is turned on.
  • the electric charge generated and accumulated therein is discharged to the signal line 6.
  • the TFT 8 is turned off when an OFF voltage is applied to the connected scanning line 5 and an OFF voltage is applied to the gate electrode 8g, and the emission of charges from the radiation detection element 7 to the signal line 6 is stopped.
  • the charges generated in the radiation detection element 7 are held and accumulated in the radiation detection element 7.
  • FIG. 5 is a sectional view taken along line BB in FIG.
  • a gate electrode 8g of a TFT 8 made of Al, Cr, or the like is formed on the surface 4a of the substrate 4 so as to be integrally laminated with the scanning line 5, and the gate electrode 8g and the surface 4a.
  • the radiation detecting element 7 is disposed above the gate electrode 8g on the gate insulating layer 81 made of silicon nitride (SiNx) or the like laminated thereon via a semiconductor layer 82 made of hydrogenated amorphous silicon (a-Si) or the like.
  • the source electrode 8 s connected to the first electrode 74 and the drain electrode 8 d formed integrally with the signal line 6 are laminated.
  • the source electrode 8s and the drain electrode 8d are divided by a first passivation layer 83 made of silicon nitride (SiNx) or the like, and the first passivation layer 83 covers both the electrodes 8s and 8d from above.
  • ohmic contact layers 84a and 84b formed in an n-type by doping hydrogenated amorphous silicon with a group VI element are stacked between the semiconductor layer 82 and the source electrode 8s and the drain electrode 8d, respectively.
  • the TFT 8 is formed as described above.
  • an auxiliary electrode 72 is formed by laminating Al, Cr, or the like on the insulating layer 71 formed integrally with the gate insulating layer 81 on the surface 4 a of the substrate 4.
  • a first electrode 74 made of Al, Cr, Mo or the like is laminated on the auxiliary electrode 72 with an insulating layer 73 formed integrally with the first passivation layer 83 interposed therebetween.
  • the first electrode 74 is connected to the source electrode 8 s of the TFT 8 through the hole H formed in the first passivation layer 83.
  • a p layer 77 formed by doping a group III element into silicon and forming a p-type layer is formed by laminating sequentially from below.
  • the electromagnetic wave When radiation enters from the radiation incident surface R of the housing 2 of the radiographic imaging apparatus 1 and is converted into an electromagnetic wave such as visible light by the scintillator 3, and the converted electromagnetic wave is irradiated from above in the figure, the electromagnetic wave is detected by radiation.
  • the electron hole pair is generated in the i layer 76 by reaching the i layer 76 of the element 7. In this way, the radiation detection element 7 converts the electromagnetic waves irradiated from the scintillator 3 into electric charges.
  • a second electrode 78 made of a transparent electrode such as ITO is laminated and formed so that the irradiated electromagnetic wave reaches the i layer 76 and the like.
  • the radiation detection element 7 is formed as described above. The order of stacking the p layer 77, the i layer 76, and the n layer 75 may be reversed. Further, in the present embodiment, a case where a so-called pin-type radiation detection element formed by sequentially stacking the p layer 77, the i layer 76, and the n layer 75 as described above is used as the radiation detection element 7. However, it is not limited to this.
  • a bias line 9 for applying a bias voltage to the radiation detection element 7 is connected to the upper surface of the second electrode 78 of the radiation detection element 7 via the second electrode 78.
  • the second electrode 78 and the bias line 9 of the radiation detection element 7, the first electrode 74 extended to the TFT 8 side, the first passivation layer 83 of the TFT 8, that is, the upper surfaces of the radiation detection element 7 and the TFT 8 are The upper side is covered with a second passivation layer 79 made of silicon nitride (SiNx) or the like.
  • one bias line 9 is connected to a plurality of radiation detection elements 7 arranged in rows, and each bias line 9 is connected to a signal line 6. Are arranged in parallel with each other. Further, each bias line 9 is bound to the connection 10 at a position outside the detection portion P of the substrate 4.
  • each scanning line 5, each signal line 6, and connection 10 of the bias line 9 are input / output terminals (also referred to as pads) provided near the edge of the substrate 4. 11 is connected.
  • each input / output terminal 11 has a COF (Chip On ⁇ Film) 12 in which a chip such as an IC 12 a is incorporated, an anisotropic conductive adhesive film (Anisotropic Conductive Film) or an anisotropic conductive paste (Anisotropic paste). It is connected via an anisotropic conductive adhesive material 13 such as Conductive Paste).
  • the COF 12 is routed to the back surface 4b side of the substrate 4 and connected to the PCB substrate 33 described above on the back surface 4b side.
  • substrate 4 part of the radiographic imaging apparatus 1 is formed.
  • illustration of the electronic component 32 and the like is omitted.
  • FIG. 7 is a block diagram illustrating an equivalent circuit of the radiographic imaging apparatus 1 according to the present embodiment
  • FIG. 8 is a block diagram illustrating an equivalent circuit for one pixel constituting the detection unit P.
  • each radiation detection element 7 of the detection unit P of the substrate 4 has the bias line 9 connected to the second electrode 78, and each bias line 9 is bound to the connection 10 to the bias power supply 14. It is connected.
  • the bias power supply 14 applies a bias voltage to the second electrode 78 of each radiation detection element 7 via the connection 10 and each bias line 9.
  • the bias power source 14 is connected to a control unit 22 described later, and the control unit 22 controls a bias voltage applied to each radiation detection element 7 from the bias power source 14.
  • the current detection means 43 for detecting the amount of current flowing through the connection 10 is provided in the connection 10 of the bias line 9.
  • the current detection means 43 can detect the start and end of radiation irradiation by detecting the increase or decrease of the current flowing through the connection 10. In the present invention, the current detection means 43 is not necessarily provided.
  • the bias line 9 is connected via the second electrode 78 to the p-layer 77 side (see FIG. 5) of the radiation detection element 7.
  • the bias power supply 14 supplies a voltage equal to or lower than a voltage applied to the second electrode 78 of the radiation detection element 7 via the bias line 9 as a bias voltage on the first electrode 74 side of the radiation detection element 7 (that is, a so-called reverse bias voltage). Is applied.
  • the first electrode 74 of each radiation detection element 7 is connected to the source electrode 8s of the TFT 8 (indicated as S in FIGS. 7 and 8), and the gate electrode 8g of each TFT 8 (FIGS. 7 and 8). Are respectively connected to the lines L1 to Lx of the scanning line 5 extending from a gate driver 15b of the scanning driving means 15 described later. Further, the drain electrode 8 d (denoted as D in FIGS. 7 and 8) of each TFT 8 is connected to each signal line 6.
  • the scanning drive unit 15 includes a power supply circuit 15a that supplies an ON voltage and an OFF voltage to the gate driver 15b, and a voltage applied to each of the lines L1 to Lx of the scanning line 5 between the ON voltage and the OFF voltage.
  • a gate driver 15b that switches between an ON voltage application state and an OFF voltage application state of each TFT 8 is provided.
  • Each signal line 6 is connected to each readout circuit 17 formed in the readout IC 16. Note that the readout IC 16 is provided with one readout circuit 17 for each signal line 6.
  • the readout circuit 17 includes an amplification circuit 18, a correlated double sampling circuit 19, an analog multiplexer 21, and an A / D converter 20. 7 and 8, the correlated double sampling circuit 19 is represented as CDS. In FIG. 8, the analog multiplexer 21 is omitted.
  • the amplifier circuit 18 is configured by a charge amplifier circuit, and is configured by connecting a capacitor 18b and a charge reset switch 18c in parallel to the operational amplifier 18a and the operational amplifier 18a, respectively.
  • a power supply unit 18 d for supplying power to the amplifier circuit 18 is connected to the amplifier circuit 18.
  • the signal line 6 is connected to the inverting input terminal on the input side of the operational amplifier 18a of the amplifier circuit 18, and the reference potential V0 is applied to the non-inverting input terminal on the input side of the amplifier circuit 18. Yes.
  • the reference potential V0 is set to an appropriate value, and in this embodiment, for example, 0 [V] is applied.
  • the charge reset switch 18c of the amplifier circuit 18 is connected to the control means 22 to be described later, and ON / OFF is controlled by the control means 22.
  • ON / OFF is controlled by the control means 22.
  • the amplification circuit 18 outputs a voltage value according to the amount of charge output from each radiation detection element 7 and converts the charge voltage.
  • the charge reset switch 18c When the charge reset switch 18c is turned on, the input side and the output side of the amplifier circuit 18 are short-circuited, and the charge accumulated in the capacitor 18b is discharged to reset the amplifier circuit 18. ing.
  • the amplifier circuit 18 may be configured to output a current in accordance with the charge output from the radiation detection element 7.
  • the “reading process of data from the radiation detecting element 7” includes reading process of the actual image data J as data based on the accumulated charge amount of the radiation detecting element 7 at the time of radiation irradiation, and radiation at the time of non-irradiating radiation There are dark image data B, BH1, BH2, etc. as data based on the accumulated charge amount (dark charge) of the detection element 7. These are collectively referred to as “data reading process from the radiation detection element 7”. And Further, in the case of “data D”, the real image data J and the dark image data B, BH1, and BH2 are collectively shown, and in the case of “image data G”, the real image data J is the dark image data. Data corrected based on data B is shown.
  • each radiation detection element 7 During the process of reading data from each radiation detection element 7, the charge is read from each radiation detection element 7, and the voltage value output by charge-voltage conversion by the amplifier circuit 18 is sampled by the correlated double sampling circuit 19. And output as data D downstream.
  • the data D of each radiation detection element 7 output from the correlated double sampling circuit 19 is transmitted to the analog multiplexer 21 (see FIG. 7), and is sequentially transmitted from the analog multiplexer 21 to the A / D converter 20.
  • the A / D converter 20 sequentially converts the data into digital value data D, outputs it to the storage means 40, and sequentially stores it.
  • the lines L1 to Lx of the scanning line 5 to which the ON voltage is applied are sequentially switched while the radiations as described above are performed.
  • a process for reading data from the detection element 7 is performed.
  • control means 22 Here, the structure of the control means 22 in this embodiment is demonstrated, referring FIG.7 and FIG.8.
  • the control unit 22 is connected to the nonvolatile storage unit 40 and the antenna device 39 described above.
  • the control means 22 is connected to a battery 41 for supplying power to each member such as the detection section P, the scanning drive means 15, the readout circuit 17, the storage means 40, and the bias power supply 14.
  • the battery 41 is provided with a connection terminal 42 for charging the battery 41 by supplying power to the battery 41 from a charging device (not shown) such as a cradle.
  • control means 22 controls the bias power supply 14 to set a bias voltage to be applied to each radiation detection element 7 from the bias power supply 14, or the charge reset switch 18 c of the amplification circuit 18 of the readout circuit 17.
  • Various processes such as ON / OFF control and transmission of a pulse signal to the correlated double sampling circuit 19 to control ON / OFF of the sample hold function are executed.
  • control means 22 performs scanning from the scanning driving means 15 to the scanning driving means 15 at the time of reset processing of each radiation detecting element 7 or reading of data D from each radiation detecting element 7 after radiographic imaging.
  • a pulse signal for switching the voltage applied to the gate electrode 8g of each TFT 8 between the ON voltage and the OFF voltage via the line 5 is transmitted.
  • control unit 22 is a computer configured by a CPU (Central Processing Unit), a ROM (Read Only Memory), a RAM (Random Access Memory), and the like (not shown), and each functional unit of the radiation image capturing apparatus 1.
  • the operation etc. are controlled.
  • the ROM stores, for example, an imaging control program for performing operation control of each component of the radiographic imaging device 1 at the time of imaging, a dark image data acquisition control program for determining an output abnormality of each radiation detection element 7, and the like. Yes.
  • Various programs, information, and the like are not limited to being stored in the ROM, and a separate program memory or the like may be provided and stored therein.
  • FIG. 9 is an explanatory diagram showing each process during photographing.
  • the radiation image capturing apparatus 1 is installed at a radiation irradiation position of the radiation generating apparatus 52 (see FIG. 11) in the radiation image capturing system 50 at the time of capturing.
  • control means 22 applies an ON voltage to the lines L1 to Lx of the scanning line 5 simultaneously or sequentially and turns on each charge reset switch 18c so as to be stored in each radiation detection element 7.
  • the charge is reset (FIG. 9: K1).
  • the radiation generator 52 starts irradiation of radiation in synchronization with the radiographic imaging device 1 under the control of the console 58 (see FIG. 11), and the control means 22 scans each scanning line 5 through each scanning line 5.
  • An OFF voltage is simultaneously applied to the TFTs 8 connected to the line 5, and the charge of the photographed image is accumulated for each radiation detection element 7 according to the radiation dose (FIG. 9: K2).
  • the charge accumulation time of the photographed image is individually set to an appropriate value according to imaging conditions such as an imaging region such as the chest and abdomen of the patient's body as a subject and a radiation dose.
  • a setting input unit may be provided in the control unit 22 so that an arbitrary time can be set.
  • a table in which a suitable accumulation time is determined according to individual imaging conditions such as an imaging region and a radiation dose is stored in the ROM 23b.
  • a storage time may be automatically selected from a table in response to an input of imaging conditions from the setting input means.
  • an ON voltage is sequentially applied to each scanning line 5 so that each radiation detection element 7 connected to each scanning line 5 is connected to each amplification circuit 18 for each scanning line 5.
  • the charge is discharged, the voltage based on the amount of accumulated charge is A / D converted, and is sequentially stored in the storage means 40 as the actual image data J of each radiation detecting element 7 (FIG. 9: K3).
  • the OFF voltage is simultaneously applied to all the scanning lines 5 to start accumulation, while the ON voltage is sequentially applied to the scanning lines 5 to read out and complete the accumulation. Different for each line.
  • each radiation detection element 7 Reset is performed (FIG. 9: K4).
  • charge accumulation processing of a dark image by each radiation detection element 7 is executed. That is, in this dark image charge accumulation process, the radiation generator 52 is not irradiated with radiation under the control of the console 58, and each radiation detection element 7 is darkened in the same accumulation time as in the above imaging for each scanning line. Image charge accumulation (dark charge accumulation) is performed (FIG. 9: K5).
  • the voltage value corresponding to the amount of charge accumulated in each capacitor 18b is A / D converted and read as dark image data B of each radiation detection element 7 (FIG. 9: K6).
  • the average value of the dark image data for each radiation detection element 7 obtained by averaging the dark image data B of each radiation detection element 7 obtained each time by repeating the steps K4 to K6 a plurality of times is obtained as a formal darkness. It may be adopted as the image data B.
  • the actual image data J acquired by the above processing for each radiation detection element 7 and the dark image data B acquired accompanying the capturing are set as an external device.
  • the console 58 the data value is corrected by taking the difference of the dark image data B with respect to the actual image data J for each radiation detection element 7, and the image data of each radiation detection element 7 is acquired.
  • each radiation detection element 7 has an offset amount due to dark charges accumulated in each radiation detection element 7 in the accumulation time from the reset process to the readout process at the time of imaging.
  • This dark charge is generated by thermal excitation or the like of each radiation detection element 7 itself, and the offset due to the dark charge has a different value for each radiation detection element 7.
  • the actual image data J of each radiation detection element 7 includes a charge (dark charge) derived from thermal excitation caused by heat of each radiation detection element 7 itself, etc. ) Are included in a superimposed manner.
  • the radiographic imaging apparatus 1 detects dark charges generated by thermal excitation or the like of each element itself as dark image data B for each radiation detection element 7 in a state in which radiation is not irradiated, and together with the actual image data J This is transmitted to the console 58, and the offset of the dark charge superposition can be removed from the photographed image data J on the console 58 side.
  • the acquisition processing (K4 to K6) of the dark image data B at the time of photographing is performed for detection of dark charges derived from thermal excitation or the like due to heat of each radiation detection element 7 itself. It is desirable that the temperature state of the detection element 7 is close to that at the time of acquisition of the actual image data, and therefore, the acquisition processing of the actual image data J and the acquisition processing of the dark image data B are continuous so as not to be separated in time. It is desirable to do it automatically. On the contrary, if the processing is continuous, the dark image data B acquisition processing may be performed first. In addition, as described above, when dark image data is acquired a plurality of times and the average value is set to the formal dark image data B, the dark image is obtained before and after the acquisition process of the actual image data J. Data B may be acquired and averaged.
  • FIG. 10A and FIG. 10B are explanatory diagrams showing respective steps at the time of obtaining dark image data for output abnormality determination.
  • the acquisition of dark image data for output abnormality determination is performed by performing dark image charge accumulation processing at a first accumulation time and a second accumulation time, each having a different length, to obtain dark image data BH1 and BH2. Is called.
  • the acquisition of dark image data for determining the output abnormality is not performed accompanying radiographic image capturing, and is not particularly limited as to when it is executed.
  • the control means 22 may be provided with an operation input means for executing dark image data acquisition processing for output abnormality determination, and may be arbitrarily executed by an operation, or may be executed periodically and automatically. You may comprise.
  • the acquisition of the dark image data BH1 for the output abnormality determination based on the first accumulation time and the acquisition of the dark image data BH2 for the output abnormality determination based on the second accumulation time are performed continuously, and the time It is designed not to be executed after each other.
  • the radiographic image capturing apparatus 1 is configured to acquire two types of dark image data for determining the output abnormality of each radiation detection element 7 with different accumulation times.
  • the dark image data for determining the output abnormality may be acquired.
  • the control unit 22 first or sequentially applies to the lines L1 to Lx of the scanning line 5 in advance.
  • an ON voltage is applied to each charge reset switch 18c and each charge reset switch 18c is turned on to reset the charge accumulated in each radiation detection element 7 (FIG. 10A: K11).
  • the control means 22 applies an OFF voltage to the TFTs 8 connected to the respective scanning lines 5 through all the scanning lines 5 at the same time.
  • the dark image charge is accumulated for (FIG. 10A: K12).
  • the first accumulation time at this time is set to be longer than at least the above-described accumulation time at the time of photographing.
  • the first accumulation time may be set several times to several tens of times or longer, but the dark charge is not saturated. It is desirable to limit the range.
  • the accumulation time at the time of shooting is set to 500 [ms], and the first accumulation time is set to 10 [s].
  • the accumulation start is simultaneous for all the scanning lines, whereas the accumulation end is different for each scanning line. Strictly speaking, the accumulation time differs for each scanning line, but the explanation is complicated. Therefore, the accumulation time here indicates, for example, the accumulation time of the scanning line where accumulation ends first as a representative value.
  • Image data BH1 is detected and read out by sequentially storing it in the storage means 40 (FIG. 10A: K13).
  • the steps K11 to K13 are also repeatedly executed a plurality of times, and each radiation obtained by averaging the dark image data BH1 of each radiation detecting element 7 obtained each time is obtained.
  • An average value of dark image data for each detection element 7 may be adopted as the formal dark image data BH1.
  • the steps K21 to K23 of the dark image data BH2 acquisition process for determining the output abnormality in the second accumulation time are set longer than the first accumulation time, as shown in FIG. 10B.
  • the detailed description is omitted because it is exactly the same except for the point.
  • the second accumulation time is set to 20 [s], for example, twice the first accumulation time.
  • the processes of K21 to K23 are repeatedly executed a plurality of times, and each radiation detection element 7 obtained by averaging the dark image data BH2 of each radiation detection element 7 obtained each time.
  • the average value of the dark image data may be adopted as the formal dark image data BH2.
  • dark image data BH1 for output abnormality determination based on the first accumulation time and dark image data BH2 for output abnormality determination based on the second accumulation time are set as an external device.
  • To the console 58. Processing on the console 58 side in the dark image data BH1 and BH2 for the output abnormality determination will be described later.
  • the acquisition processing of the dark image data BH1 for output abnormality determination based on the first accumulation time and the dark image data BH2 for output abnormality determination based on the second accumulation time is continuously performed without taking time. Although it is desirable to be performed, any of these acquisition processes may be performed first.
  • the radiographic image capturing system 50 is a system that assumes radiographic image capturing performed in, for example, a hospital or a clinic, and can be employed as a system that captures a medical diagnostic image as a radiographic image, but is not necessarily limited thereto. Not.
  • FIG. 11 is a diagram showing an overall configuration of the radiation image capturing system 50 in the present embodiment.
  • the radiographic imaging system 50 includes, for example, an imaging room R ⁇ b> 1 that performs imaging of a subject that is a part of a patient by irradiating radiation (an imaging target part of the patient), and an operator such as a radiographer Are arranged in the anterior chamber R2 for performing various operations such as control of radiation applied to the subject, and outside thereof.
  • a bucky device 51 that can be loaded with the radiographic imaging device 1 described above, a radiation generating device 52 that includes an X-ray tube (not shown) that generates radiation to irradiate a subject, the radiographic imaging device 1 and a console.
  • a base station 54 equipped with a wireless antenna 53 is provided as a communication means for relaying these communications when wirelessly communicating with 58.
  • FIG. 11 shows a case where the portable radiographic imaging device 1 is used by being loaded into the cassette holding portion 51a of the standing-up imaging bucky device 51A or the standing-up imaging bucky device 51B.
  • the radiographic imaging device 1 may be formed integrally with the bucky device 51, a support base, or the like. Further, as shown in FIG. 11, the radiographic image capturing apparatus 1 and the base station 54 can be connected by a cable so that data can be transmitted by wired communication via the cable.
  • the cradle 55 that reads the cassette ID from the radiographic image capturing apparatus 1 and notifies the console 58 via the base station 54 when the radiographic image capturing apparatus 1 is inserted into the radiographing room R1.
  • the cradle 55 may be configured to charge the radiographic image capturing apparatus 1 or the like.
  • the front chamber R2 is provided with an operation console 57 for controlling radiation irradiation, which includes switch means 56 for instructing the radiation generator 52 to start radiation irradiation and the like.
  • the configuration of the radiographic image capturing apparatus 1 is as described above.
  • the radiographic image capturing apparatus 1 may be used by being loaded into the bucky device 51 as described above, but it is not loaded into the bucky device 51. It can also be used in a single state.
  • the radiation image capturing apparatus 1 is arranged in a single state, for example, on the upper surface side of a bed provided in the imaging room R1 or a bucky apparatus 51B for supine photography as shown in FIG. (See FIG. 1)
  • the patient's hand which is the subject, can be placed on the top, or the patient's waist, legs, etc. lying on the bed can be inserted between the bed and the bed. It has become.
  • radiation image capturing is performed by irradiating the radiation image capturing apparatus 1 with radiation from a portable radiation generating device 52B or the like via a subject.
  • the console 58 that controls the entire radiographic imaging system 50 is provided outside the imaging room R1 and the front room R2.
  • the console 58 is configured to be provided in the front room R2. Is also possible.
  • the console 58 is constituted by a computer or the like in which a CPU, a ROM, a RAM, an input / output interface and the like (not shown) are connected to a bus.
  • a predetermined program is stored in the ROM, and the console 58 reads out the necessary program, expands it in the work area of the RAM, executes various processes according to the program, and controls the entire radiographic imaging system 50 as described above. Is supposed to do.
  • the console 58 is connected to the above-described base station 54, console 57, storage means 59 composed of a hard disk or the like, and a cradle 55 or the like is connected via the base station 54.
  • the radiation generating device 52 and the like are connected via this.
  • the console 58 is provided with a display screen 58a such as a CRT (Cathode Ray Tube) or LCD (Liquid Crystal Display), and other input means such as a keyboard and a mouse are connected thereto.
  • CTR Cathode Ray Tube
  • LCD Liquid Crystal Display
  • the console 58 When the console 58 is notified of the cassette ID of the radiographic imaging apparatus 1 from the cradle 55 via the base station 54, the console 58 saves it in the storage means 59, and the radiographic imaging apparatus 1 existing in the imaging room R1.
  • the storage unit 59 stores the real image data J received from the radiographic image capturing apparatus 1, the dark image data B associated therewith, the dark image data BH1 for determining output abnormality based on the first accumulation time, the second
  • a defective element map showing the arrangement of the radiation detection element 7 that performs abnormal output of the radiation image capturing apparatus 1 in the detection unit P Is remembered.
  • the radiation detecting element 7 is formed by integrating millions, tens of millions or more of the elements in the detection part P, and some of them show abnormal output from the beginning of manufacture. It is.
  • the abnormal output of the radiation detection element 7 is one that does not output any charge despite the radiation irradiation, one that outputs only a constant regardless of changes in the radiation dose, and is output every time a fixed dose of radiation is incident. Are different and do not show the law.
  • the object of abnormality determination is a radiation detection element 7 that performs only a constant output regardless of a change in radiation dose (in some cases, random output)
  • the radiation detection element 7 that performs the detection can also be detected), and the radiation detection element 7 that is newly determined to be abnormal in output by the abnormality determination is sequentially added.
  • the defect element map may be one in which only position information (position coordinates) in the detection unit P of the radiation detection element 7 that is regarded as an output abnormality is recorded, or normal or abnormal for all the radiation detection elements 7 of the detection unit P. May be recorded.
  • the console 58 reads the two dark image data BH1 and BH2 from the storage means 59 (step S11), and calculates the difference data ⁇ BH by subtracting them (step S12). That is, for each radiation detection element 7, the dark image data BH1 is subtracted from the dark image data BH2, and difference data ⁇ BH for each radiation detection element 7 is calculated.
  • FIG. 13 is a conceptual diagram showing the difference calculation process.
  • the pixel position on the horizontal axis indicates, for example, the arrangement direction of the radiation detection elements 7 along the scanning line 5, and the vertical axis indicates dark image data or a difference value thereof. Since each radiation detection element 7 in the detection unit P has a value corresponding to the amount of charge accumulated in a non-radiation state, the influence of variation due to a difference in incident dose is suppressed. In addition, since the temperature difference between the radiation detecting elements 7 is small and almost constant unless the state is special, it is considered that the influence of the temperature difference is small.
  • one of the factors that cause variation in dark image data for each pixel position in the normal radiation detection element 7 is a difference in characteristics when reading is performed by a plurality of readout circuits 17 individually provided in the scanning line direction. Conceivable. Although it is possible to directly determine a threshold value for determining an output abnormality for the dark image data BH1 or BH2 and determine an output abnormality, the determination is made in consideration of the influence of the variation for each readout circuit 17 described above. It is difficult to avoid a certain decrease in accuracy. However, by taking the difference between the dark image data BH1 and BH2 as in step S12, the variation for each readout circuit 17 is canceled, and the value of the output abnormality appears remarkably without being buried in the variation. The threshold value can be brought closer to the normal value, and the radiation abnormality detecting element 7 having the output abnormality can be accurately determined.
  • the console 58 calculates the standard deviation of each difference data ⁇ BH.
  • the upper limit threshold value of the difference data ⁇ BH for output abnormality determination is set to ⁇ + 5 ⁇
  • the lower limit threshold value is set to ⁇ 5 ⁇ .
  • each of the dark image data BH1 and BH2 serving as the base data of the difference data ⁇ BH has accumulated charges in each radiation detection element 7 with an accumulation time longer than the accumulation time during normal imaging. The effect of this will be described with reference to FIGS. 14A and 14B.
  • FIG. 14A is a diagram showing the correspondence between dark image data and the frequency (number of elements) when dark image charge accumulation is performed with the charge accumulation time of each radiation detection element 7 being the same as in normal imaging.
  • FIG. 14B shows the correspondence between dark image data and the frequency (number of elements) when dark image charge accumulation is performed with the charge accumulation time of each radiation detection element 7 set longer than that during normal imaging.
  • FIG. In the case where the charge accumulation time of each radiation detection element 7 is the same as in normal imaging, for example, when the value d1 deviates significantly from the value where the dark image data of the radiation detection element 7 that is abnormal in output is concentrated in the distribution. In this case, it is possible to determine the radiation detection element 7 that causes an output abnormality by setting a value (for example, the value indicated by a dotted line) that is far from the value where the distribution is concentrated with a margin.
  • a value for example, the value indicated by a dotted line
  • the radiation detection element 7 that is becoming abnormal in output if it is determined until the value d2 close to the value where the distribution is concentrated and the determination of the output abnormality is performed with high accuracy, the radiation detection element that performs normal output It becomes difficult to set a threshold value that enables discrimination from 7. That is, it is necessary to set a value close to the value where the distribution is concentrated as a threshold value, and there is a high possibility that it is determined that the output is abnormal up to the normal radiation detection element 7, and a certain decrease in determination accuracy is inevitable.
  • a value d3 in FIG. 14B indicates an output as a result of extending the accumulation time for the radiation detection element 7 that has output the value d2.
  • step S12 which is a step for obtaining the difference between dark image data BH1 and BH2, is omitted.
  • a threshold value for determination is calculated by obtaining a standard deviation for the dark image data BH1 (or BH2) of each radiation detection element 7, and further, a dark image of each radiation detection element 7 is calculated based on the threshold value.
  • the determination for the data BH1 (or BH2) is performed.
  • the radiation detection element 7 is registered in the defect element map in the storage unit 59 (step S15).
  • the console 58 stores the positional information of the radiation detection element 7 determined as abnormal in output or A process of adding an address or the like to the map is executed.
  • the defect element map is, for example, information indicating whether the radiation detection elements 7 are normal or abnormal as described above
  • the recording is performed for the radiation detection elements 7 determined to be abnormal in output. Execute the process of rewriting it to indicate something abnormal.
  • the console 58 functions as “output abnormality determination means” and “registration means” by executing the output abnormality determination program.
  • the processing contents of the image display control performed by the CPU of the console 58 according to the image display control program will be described based on the flowchart of FIG.
  • the console 58 reads out the real image data J in each radiation detection element 7 and the dark image data B for correcting the real image data acquired accompanying it from the storage means 59 (step S21).
  • the image data excluding the offset component of the dark charge by difference is calculated (step S22). Note that correction (calibration) of sensitivity characteristics of each radiation detection element 7 may be further performed on the image data of each radiation detection element according to a known method.
  • the console 58 refers to the defect element map in the storage device 59 and identifies the radiation detection element 7 having an abnormal output. Then, when the radiation detection element 7 having an abnormal output is specified, interpolation processing is performed from the image data of the surrounding radiation detection elements 7 (step S23). An example of the interpolation processing method is shown in FIG.
  • Image data G (m, n) (m is the position coordinate in the direction of the scanning line 5, and n is the position coordinate in the direction of the signal line 6)
  • An average of (m, n + 1), G (m + 1, n-1), G (m + 1, n), and G (m + 1, n + 1) is calculated and replaced with the value of G (m, n).
  • the console 58 displays an image on the display screen 58a (step S24).
  • the control unit 22 is not irradiated with radiation (so-called dark charge acquisition).
  • Control to acquire dark image data BH1 and BH2 for determining an output abnormality of the radiation detection element 7 from the readout circuit 17 based on the charge accumulated for each radiation detection element 7 with a longer accumulation time than at the time of imaging. Is going.
  • the charge accumulation time of each radiation detection element 7 during the charge accumulation of the dark image is made longer, the value where the distribution of the dark image data of the normal radiation detection element 7 is concentrated and the radiation detection of the abnormal output is performed.
  • the difference from the dark image data by the element 7 can be widened according to the accumulation time. As a result, it is easy to distinguish between normal values and abnormal values, and the threshold value is also likely to take an appropriate value. As a result, it is possible to reduce the possibility that the normal radiation detection element 7 is determined to be abnormal in output, and to improve the determination accuracy. Further, the radiation detection element 7 that outputs dark image data close to a normal value while causing an abnormality can be identified separately from the normal radiation detection element 7. For example, the radiation detection that was originally normal is detected. Even when the element 7 is gradually becoming abnormal, it can be determined to be abnormal at an early stage by determination, and the frequency of maintenance for monitoring the radiation detecting element 7 with abnormal output can also be reduced.
  • the control means 22 of the radiographic imaging device 1 obtains dark image data BH1 and BH2 for determining a plurality of (two in this embodiment) output abnormality for each radiation detection element 7 by changing the accumulation time, This is transmitted to the console 58 as an external device. Therefore, on the console 58 side, the difference data ⁇ BH can be obtained for each radiation detection element 7 for the two dark image data BH1 and BH2. In this case, as described above, the difference data ⁇ BH can cancel the influence of the variation in the output characteristics in the plurality of readout circuits 17, and thus radiation that is abnormal in output in the difference data ⁇ BH in which the variation is reduced. It becomes easy to identify the difference data ⁇ BH based on the output of the detection element 7 as being prominent, and it is possible to further improve the determination accuracy of the radiation detection element 7 with an abnormal output.
  • the dark image data BH1 and BH2 of each radiation detection element 7 a plurality of data is acquired by accumulating a plurality of times, and the average value thereof is also used as the formal dark image data BH1 and BH2. It is good, but when averaging is done in such a way, noise components such as horizontal noise can be removed, and furthermore, it is possible to accurately detect the radiation detection element 7 that causes output abnormality. It is said.
  • radiographic imaging device 1 In the radiographic imaging device 1 described above, when processing for obtaining dark image data BH1 and BH2 for output abnormality determination of the radiation detection element is performed, all of these dark image data BH1 and BH2 are transmitted to the console 58 side.
  • the determination of the radiation detection element 7 that is abnormal in output from the dark image data BH1 and BH2 and the registration of the defect element map are all referred to the console 58.
  • the radiographic imaging device stores and holds the defect element map.
  • a configuration may be adopted in which the radiation detection element 7 determined to be abnormal in output is determined from the dark image data BH1 and BH2 and is registered in the defect element map.
  • FIG. 17 is a block diagram showing a configuration of such a radiographic image capturing apparatus 100.
  • the radiographic imaging device 100 has all the same configurations as those of the radiographic imaging device 1 described above. Therefore, in the description of the radiographic image capturing apparatus 100, the same components as those of the radiographic image capturing apparatus 1 are denoted by the same reference numerals and description thereof is omitted.
  • the detection unit P, the gate driver 15b, and the power supply circuit 15a are not shown.
  • the radiographic image capturing apparatus 100 includes a control unit 122, and the control unit 122 includes a CPU 123, a RAM 124, and a ROM 125, similar to the control unit 22 described above. Further, the control unit 122 includes a program memory 126, and the photographing control program 127 for executing the process of FIG. 9 and dark image data for executing the process of FIGS. 10A and 10B. The acquisition control program 128 is stored.
  • the program memory 126 stores an output abnormality determination program 129 that has been processed by the CPU of the console 58 described above.
  • the output abnormality determination program 129 is a program for executing the same processing as the processing of FIG. 12 executed by the CPU of the console 59.
  • the output abnormality is detected for the detection unit P possessed by the device.
  • the radiation detecting element 7 can be specified.
  • this makes it possible to register the radiation detection element 7 whose output is abnormal with respect to the defective element map M. That is, the control means 22 that executes the output abnormality determination program 129 functions as “output abnormality determination means” and “registration means”.
  • the storage unit 140 provided in the control unit 122 includes an output abnormality in addition to the actual image data J, the dark image data B, and the dark image data BH1 and BH2 for determining the output abnormality for each radiation detection element 7.
  • the configuration is such that difference data ⁇ BH and defect element map M obtained in the course of execution of the determination program 129 are stored.
  • the radiographic image capturing apparatus 100 executes the same processing as steps S21 to S23 in FIG. 15, and the image data G subjected to the interpolation processing is transmitted to the console 58 through the antenna device 39. Therefore, the storage unit 140 is configured to store image data G for one screen that has been completed up to the interpolation processing.
  • the radiographic image capturing apparatus 100 obtains the image data G, the processing burden on the console 58 side can be reduced.
  • the radiation image capturing apparatus 100 has a defect element map M and can manage information on the radiation detection elements 7 that cause output abnormalities by self-processing, individual radiation image capturing on the console 58 side is possible. It is also possible to eliminate the management of the device 100.
  • the defect element map M may be managed by both the radiation image capturing apparatus 100 side and the console 58 side. In this case, the radiographic imaging apparatus 100 may be configured to transmit the data of the defective element map M to the console 58 every time the registered content of the defective element map M is updated.
  • the correction is performed by subtracting the dark image data B from the actual captured image data J for each radiation detection element 7. Calculating the completed image data and transmitting the corrected image data to the console 58 instead of the actual image data J and the dark image data B, or the difference between the dark image data BH1 and BH2 for each radiation detection element 7 It is possible to calculate the data ⁇ BH and transmit the difference data ⁇ BH to the console 58 instead of the dark image data BH1 and BH2, or to perform both. With these configurations, the amount of data transmitted from the radiographic apparatus to the console 58 can be reduced, and the transfer time can be shortened.
  • the defective pixel map creation system 200 is a system that creates a defective pixel map by determining a defective pixel by performing an inspection involving radiation irradiation, for example, at the time of a shipping inspection performed before the radiation image capturing apparatus 1 is shipped.
  • FIG. 18 is a diagram showing the overall configuration of the defective pixel map creation system 200.
  • the defective pixel map creation system 200 creates a defective pixel map for the substrate 4 at the previous stage stored in the housing 2 of the radiation imaging apparatus 1. That is, the substrate 4 is in a state where all the configurations (the entire internal configuration of the housing 2 in FIG. 2) directly provided on both surfaces of the substrate 4 such as the detection unit P and the scintillator 3 are already mounted or formed.
  • the COF 12, the substrate 33, the scanning drive unit 15, the readout IC 16, the control unit 22, the storage unit 40, the antenna device 39, and the like are all mounted, and a radiographic image can be captured when power is supplied.
  • detection function unit 4A an electric double layer capacitor such as a lithium ion capacitor and a secondary battery such as a lithium ion battery are usually mounted on the substrate 4 as a battery 41. These are in an aging step (described later) in creating a defective pixel map. In order to avoid influences such as destruction and deterioration due to heating, the battery 41 is removed in advance or a defective pixel map is created at a stage before mounting.
  • the defective pixel map creation system 200 mainly includes a thermostatic chamber 210 as a heating unit that stores the detection function unit 4A and a defective pixel map creation device 220.
  • the thermostatic chamber 210 can accommodate the detection function unit 4A inside, has high sealing property and heat insulation, and blocks electromagnetic waves including visible light and radiation from the outside to make the inside a dark room. It is possible to do.
  • the thermostatic chamber 210 includes a heater 211 that raises the temperature inside, a temperature sensor 212 that detects the temperature inside, and a power supply circuit 213 that supplies necessary power to each part of the housed detection function unit 4A.
  • a communication unit 214 that performs wireless communication through the antenna device 39 of the housed detection function unit 4A.
  • the heater 211 and the temperature sensor 212 are connected to the controller 215, and the controller can input the setting of the internal temperature of the thermostat 210.
  • the controller performs heating control of the heater 211 based on the temperature detected by the temperature sensor 212, and performs control to maintain the constant temperature bath 210 at a set temperature.
  • the detection function unit 4A is accommodated in the thermostatic chamber 210 without the battery 41 mounted.
  • the power supply circuit 213 supplies power to the detection function unit 4A so that the detection function unit 4A housed in the thermostat 210 can execute radiographic image capturing.
  • the power supply circuit 213 is disposed outside the thermostatic chamber 210 and supplies power to the detection function unit 4A through a power supply connector 213A in the bath through wiring.
  • the power supply connector 213A is the same type as the connector that connects the battery 41 to the substrate 4, and the power supply connector 213A can be connected instead of the battery 41 being removed, and thus the detection function unit 4A can be connected. Power is supplied to each part.
  • the communication unit 214 is a wireless device in which an antenna is arranged inside the thermostat 210, and enables wireless transmission and reception with the detection function unit 4A through the antenna device 39 on the detection function unit 4A side.
  • the communication unit 214 is connected to the defective pixel map creation device 220 via a communication cable, and transmits a control command to the detection function unit 4A from the control unit 221 of the defective pixel map creation device 220 described later, or a detection function.
  • the dark image data acquired by the unit 4A can be received and transmitted to the defective pixel map creating apparatus 220.
  • the defective pixel map creation device 220 controls the detection function unit 4A heated in the thermostat 210 to acquire dark image data BH3 and BH4 for aging processing and output abnormality determination of each radiation detection element 7. The processing is executed in order, the radiation detection element 7 with abnormal output is identified from the acquired dark image data BH3 and BH4, and the defective pixel map M is created for the radiation detection element 7 with abnormal output.
  • the defective pixel map creating apparatus 220 includes a control unit 221 and various data storage units 230, and the control unit 221 includes a CPU 222, a RAM 223, and a ROM 224.
  • the control means 221 includes a program memory 225, and an aging control program 227 for causing the detection function unit 4A to execute an aging process described later, and a dark image for determining an output abnormality of each radiation detection element 7.
  • a dark image data acquisition control program 228 for causing the detection function unit 4A to execute a data acquisition process for acquiring the data BH3 and BH4, and specifying the radiation detection element 7 having an abnormal output from the acquired dark image data BH3 and BH4
  • An output abnormality determination program 229 for creating a defective pixel map M for the radiation abnormality detecting element 7 with an abnormality in output is stored.
  • control unit 221 executes the aging control program 227 to start heating the heater 211 to a set temperature (for example, 60 degrees Celsius) in the thermostatic chamber 210, and through the communication unit 214, the detection function unit A control command for executing the aging process is transmitted to the control means 22 of 4A (step S31: aging step).
  • a set temperature for example, 60 degrees Celsius
  • the detection function unit A control command for executing the aging process is transmitted to the control means 22 of 4A (step S31: aging step).
  • the aging process is a process of repeatedly executing the reset of accumulated charges, the accumulation of charges, and the charge reading operation (charge releasing operation) within a predetermined duration.
  • the detection function unit 4A resets the accumulated charge of each radiation detection element 7 by applying an ON voltage to the lines L1 to Lx of the scanning line 5 and switching each charge reset switch 18c to the ON state. Then, charge accumulation by each radiation detection element 7 is performed by turning off each charge reset switch 18 c and application of an OFF voltage to each TFT 8, and readout of charge accumulated in each radiation detection element 7 by application of an ON voltage to each TFT 8. (Discharge of electric charge) is repeatedly executed a plurality of times.
  • the control unit 221 functions as an “aging control unit” by causing the detection function unit 4A to repeatedly execute the reset, charge accumulation, and charge readout.
  • the reset, storage, and readout operations are executed in a shorter cycle than the operation at the time of normal imaging of an actual radiation image.
  • the cycle is repeatedly executed for a predetermined time.
  • the repetition time is about 10 to 20 hours, for example.
  • the charge accumulation of each radiation detection element 7 is performed in the thermostatic chamber 210 in a non-irradiated state, dark charges are accumulated, but the charge of each radiation detection element 7 in the aging process is accumulated. Accumulation is not limited to dark charges, and may be performed in a radiation irradiation state, for example.
  • the read operation of the accumulated charges of each radiation detection element 7 is not intended to acquire data but is intended to perform the discharge operation of charges, so A / D conversion and storage of the converted data are performed. Is not done.
  • step S32 dark image data acquisition step.
  • the acquisition control of the dark image data BH3 and BH4 is almost the same operation control as the acquisition of the dark image data BH1 and BH2 shown in FIGS. 10A and 10B.
  • the control means 22 of the detection function unit 4A resets the charge of each radiation detection element 7, accumulates the charge of the dark image in the third accumulation time in the non-irradiated state, and each radiation detection element 7 Read processing is executed for.
  • the third accumulation time is set so that the accumulation time at the time of shooting is longer than the accumulation time at the time of shooting.
  • the third accumulation time is set to 10 [s], which is the same as the first accumulation time in FIG. 10A.
  • the control means 22 of the detection function unit 4A resets the charge of each radiation detection element 7, accumulates the charge of the dark image in the fourth accumulation time in the non-irradiated state, and each radiation detection element 7 Is read out, and dark image data BH4 for output abnormality determination based on the fourth accumulation time of each radiation detection element 7 is acquired and transmitted to the control means 221 of the defective pixel map creation device 220.
  • the fourth accumulation time is set to a length different from the third accumulation time and longer than the accumulation time at the time of shooting. Specifically, the fourth accumulation time is set to 20 [s], which is the same as the second accumulation time in FIG. 10B.
  • the control unit 221 stores the dark image data BH4 in the storage unit 230.
  • the control means 221 functions as a “dark image data acquisition control unit” by executing control for acquiring dark image data BH3 and BH4 for output abnormality determination from the detection function unit 4A.
  • the control unit 221 reads out the two dark image data BH3 and BH4 from the storage unit 230, and calculates the difference data ⁇ BH2 by subtracting them (step S33). : Difference step). That is, the dark image data BH3 is subtracted from the dark image data BH4, and difference data ⁇ BH2 including the difference value of the output value for each radiation detection element 7 is calculated.
  • the control unit 221 functions as a “difference calculation unit” by calculating a difference between the dark image data BH3 and BH4.
  • the control unit 221 determines the output abnormality from the average value ⁇ and the standard deviation ⁇ of each difference data ⁇ BH2.
  • the upper limit threshold ⁇ + 5 ⁇ and the lower limit threshold ⁇ 5 ⁇ of the difference data ⁇ BH2 are calculated (step S34).
  • the coefficient of ⁇ is not limited to “5”, and setting means may be provided to allow arbitrary setting input.
  • the threshold value itself may be set arbitrarily.
  • the control means 221 sequentially determines the output abnormality for the difference data ⁇ BH2 of each radiation detection element 7 (step S35: determination step).
  • FIG. 20A is a diagram showing a correspondence relationship between the output value of each radiation detection element 7 and its frequency (number of elements) when the detection function unit 4A is not subjected to the aging process
  • FIG. 20B is an aging diagram for the detection function unit 4A. It is a diagram which shows the correspondence of the output value of each radiation detection element 7 at the time of processing, and its frequency (element number).
  • the control means 221 functions as a “determination unit” by determining the output abnormality of each radiation detection element 7 from the difference data of the dark image data BH3 and BH4.
  • the control unit 221 executes the output abnormality determination program 229 to register the radiation detection element 7 in the defect element map M in the storage unit 230 for the radiation detection element 7 determined to be output abnormality.
  • Step S36 defective pixel map creation step.
  • the defect element map may be a record of the position information of the radiation detection elements 7 that are abnormal in output, and whether all the radiation detection elements 7 are normal or abnormal (which radiation detection element 7 is abnormal). The information shown may be recorded.
  • the control means 221 functions as a “defective pixel map creation unit” by registering a defective pixel map.
  • the abnormality of the output value of each radiation detection element 7 is determined after the aging process is performed on the detection function unit 4A. It becomes possible to detect early by actively proceeding with an abnormal state of the radiation detecting element 7 which will cause an abnormal output later, which is not considered to be. And since the generation
  • the thermostat 210 which accommodates the detection function part 4A is provided and the aging process with respect to the detection function part 4A can be performed in a high temperature state, the aging can be efficiently advanced with a small number of process repetitions. It is possible to improve the detection accuracy of the abnormality of the detection element 7.
  • the temperature setting of the detection function unit 4A by the thermostatic chamber 210 is not limited to the above-described example as long as it is higher than the normal temperature that is the normal use environment temperature.
  • the set temperature may be set equal to the continuous use temperature in the housing 2 that is reached by the heat generation of each component of the detection function unit 4A when the radiographic imaging device 1 is used a plurality of times.
  • It may be used in the field of radiographic imaging (especially in the medical field).

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Abstract

L'invention permet de déterminer très précisément quels sont les éléments de détection de rayonnement présentant des anomalies de sortie. Le dispositif de radiographie (1) de l'invention comprend une pluralité d'éléments de détection de rayonnement (7) agencés en réseau bidimensionnel par une pluralité de lignes de balayage et de lignes de signal ; un circuit de lecture (17) qui produit soit des données d'image réelle (J), soit des données d'image sombre (B) sur la base de chaque élément de détection de rayonnement ; un moyen de communication (39) pour communiquer les données vers un dispositif externe (58) ; et un moyen de commande. Grâce à ce dispositif, le circuit de lecture produit des données d'image sombre (BH1, BH2) servant à la détermination d'anomalies de sortie des éléments de détection de rayonnement, sur la base de la charge que chaque élément de détection de rayonnement accumule quand un rayonnement n'est pas projeté pendant un temps d'accumulation qui est plus long que lors de l'imagerie.
PCT/JP2011/053189 2010-03-24 2011-02-16 Dispositif et système de radiographie et procédé et système de génération d'une carte de pixels défectueux WO2011118286A1 (fr)

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Cited By (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JP2016001855A (ja) * 2014-06-12 2016-01-07 キヤノン株式会社 画像処理装置および画像処理方法、画像処理システム
US10542184B2 (en) 2017-01-25 2020-01-21 Ricoh Company, Ltd. Photoelectric conversion device, defective pixel determining method, image forming apparatus, and recording medium

Citations (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPH07236093A (ja) * 1994-02-21 1995-09-05 Toshiba Medical Eng Co Ltd 撮像装置
JP2002101343A (ja) * 2000-09-22 2002-04-05 Toshiba Medical System Co Ltd Ｘ線平面検出器及びｘ線診断システム

Patent Citations (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPH07236093A (ja) * 1994-02-21 1995-09-05 Toshiba Medical Eng Co Ltd 撮像装置
JP2002101343A (ja) * 2000-09-22 2002-04-05 Toshiba Medical System Co Ltd Ｘ線平面検出器及びｘ線診断システム

Cited By (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JP2016001855A (ja) * 2014-06-12 2016-01-07 キヤノン株式会社 画像処理装置および画像処理方法、画像処理システム
US10140686B2 (en) 2014-06-12 2018-11-27 Canon Kabushiki Kaisha Image processing apparatus, method therefor, and image processing system
US10542184B2 (en) 2017-01-25 2020-01-21 Ricoh Company, Ltd. Photoelectric conversion device, defective pixel determining method, image forming apparatus, and recording medium

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