WO2012036494A2 - Procédé de lecture et circuit de lecture pour détecter des rayons x à des bandes d'énergie prédéfinies, et capteur de rayons x utilisant ce procédé - Google Patents

Procédé de lecture et circuit de lecture pour détecter des rayons x à des bandes d'énergie prédéfinies, et capteur de rayons x utilisant ce procédé Download PDF

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Publication number
WO2012036494A2
WO2012036494A2 PCT/KR2011/006834 KR2011006834W WO2012036494A2 WO 2012036494 A2 WO2012036494 A2 WO 2012036494A2 KR 2011006834 W KR2011006834 W KR 2011006834W WO 2012036494 A2 WO2012036494 A2 WO 2012036494A2
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WIPO (PCT)
Prior art keywords
output signal
comparison
ray
voltage
determination
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PCT/KR2011/006834
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English (en)
Korean (ko)
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WO2012036494A9 (fr
WO2012036494A3 (fr
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소명진
안태지
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주식회사 룩센테크놀러지
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Publication of WO2012036494A2 publication Critical patent/WO2012036494A2/fr
Publication of WO2012036494A3 publication Critical patent/WO2012036494A3/fr
Publication of WO2012036494A9 publication Critical patent/WO2012036494A9/fr

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    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01T—MEASUREMENT OF NUCLEAR OR X-RADIATION
    • G01T1/00—Measuring X-radiation, gamma radiation, corpuscular radiation, or cosmic radiation
    • G01T1/16—Measuring radiation intensity
    • G01T1/17—Circuit arrangements not adapted to a particular type of detector

Definitions

  • the present invention relates to an X-ray sensor, and more particularly, to a readout circuit used in the X-ray sensor.
  • the X-ray sensor is a kind of image sensor for detecting X-rays in a digital X-ray imaging apparatus to make a digital image.
  • a photon counting mode is widely used as a method of measuring current by incident X-rays.
  • a photon corresponding to the energy of X-rays is incident, a current generated by the flow of electron-holes is converted into a voltage signal, amplified, and input to a comparator.
  • the comparator compares the amplified voltage signal with a reference voltage and outputs a pulse, and the counter counts the output pulse of the comparator per unit time, thereby measuring the magnitude of the incident X-rays.
  • the effect of noise is small, radiation exposure can be reduced, and data can be obtained in digital form.
  • one comparator is used to emit one pulse when the output value from the amplifier is greater than the reference voltage, and the counter operates on the rising edge or falling edge of the pulse.
  • An object of the present invention is to provide an X-ray read integrated circuit in which the X-ray photons are counted according to various energy bands of the X-rays passed by the subject, and an X-ray sensor including the same.
  • a comparison unit comparing the voltage output signal with N reference voltages preset and outputting the N output voltages as N comparison output signals
  • a band determination unit activating a pulse output signal when the comparison output signals satisfy a determination condition set for detecting X-rays of a specific energy band
  • It may include a counter for counting the number of pulses of the pulse output signal to output the photon coefficient data.
  • the determination condition is
  • the determination condition is
  • the comparison output signal comparing the reference voltage corresponding to the upper limit of the specific energy band to be detected with the voltage output signal does not show a pulse, and the comparison comparing the reference voltage corresponding to the lower limit of the specific energy band and the voltage output signal
  • the output signal may be a condition in which a pulse appears.
  • the band determination unit determines whether the band is a predefined range of the band.
  • a decision circuit that logically determines whether the comparison output signals satisfy the decision condition
  • the comparison output signal is applied to the determination circuit as it is, or when the amount of charge is the flow of holes, the comparison output signal is inverted to determine the determination circuit. It may include a comparison output selection circuit for applying to.
  • the comparison output selection circuit comprises a plurality of two-to-one multiplexers
  • An X-ray sensor may include an X-ray read integrated circuit according to various embodiments.
  • An X-ray imaging apparatus may include an X-ray reading integrated circuit according to various embodiments.
  • the X-ray reading integrated circuit of the present invention and the X-ray sensor including the same, only the X-rays having a desired energy band can be detected by the user, so that only an image of any exposed tissue that commonly represents a specific energy band can be separated. Therefore, it is possible to implement a tissue-specific image separation function that was not possible with the conventional X-ray digital post-processing system.
  • FIG. 1 is a block diagram schematically illustrating an X-ray read integrated circuit capable of detecting multiple energy bands according to an embodiment of the present invention.
  • FIG. 2 is a detailed circuit diagram illustrating an amplifier included in the X-ray read integrated circuit of FIG. 1.
  • FIG. 3 is a detailed circuit diagram illustrating a comparator included in the X-ray read integrated circuit of FIG. 1.
  • FIG. 4 is a detailed circuit diagram illustrating a band determiner included in the X-ray read integrated circuit of FIG. 1.
  • FIG. 5 is a circuit diagram illustrating in detail an X-ray read integrated circuit capable of detecting multiple energy bands according to another embodiment of the present invention.
  • FIG. 6 is a waveform diagram when an X-ray read integrated circuit according to an exemplary embodiment of the present invention operates in an electron detection mode.
  • FIG. 7 is a waveform diagram when the X-ray read integrated circuit operates in the hole detection mode according to an embodiment of the present invention.
  • X-rays pass through an object or tissue and have an energy band specific to that object or tissue.
  • an energy band specific to that object or tissue For example, when X-rays pass through the human body, bones, muscles, and blood vessels each have different energy levels. As the X-rays are converted into energy levels of different bands according to the characteristics of the organs passing through them, the X-rays having such energy levels are incident on the photodiode, and thus the levels of the voltage signals generated by the X-rays have their own bands.
  • the X-ray read integrated circuit and the X-ray sensor using the same of the present invention is characterized in that the voltage signal generated by the X-ray incident on the photodiode has a unique band according to the type of the object or tissue, the specific among the object or human tissue Only part of the material or tissue of a certain type can be detected, and such detection images can also be combined to form a full image. This is a function impossible with a digital post-processing system by a conventional X-ray read integrated circuit.
  • the multi-energy band X-ray read integrated circuit and X-ray sensor of the present invention can be used to provide new applications for medical and industrial applications.
  • the X-ray read integrated circuit of the present invention is for detecting X-rays having energy bands falling within a desired range.
  • the N reference voltages VTH_1, VTH_2, ..., VTH_N
  • VTH_1, VTH_2, ..., VTH_N can be used to detect such a voltage signal.
  • FIG. 1 is a block diagram schematically illustrating an X-ray read integrated circuit capable of detecting multiple energy bands according to an embodiment of the present invention.
  • the X-ray read integrated circuit 10 may include a sensor unit 11 including a photodiode, an amplifier 12, a comparator 13, a band determiner 14, and a counter 15. Can be.
  • the sensor unit 11 generates a charge output Q IN when X-rays are incident.
  • the amplifier 12 receives the charge output QIN and outputs the voltage output CSAOUT converted and amplified into a voltage signal.
  • the comparator 13 compares the voltage output CSAOUT of the amplifier 12 with preset reference voltages VTH_1, VTH_2,..., VTH_N, and compares the comparison result with the N comparison outputs COMP_1, COMP_2, ..., COMP_N).
  • the band determining unit 14 is in the case where a peak of the voltage output signal CSAOUT due to the applied X-rays exists within a range of one or more reference voltages corresponding to a specific energy band, that is, the comparison unit 13
  • the comparison outputs COMP_1, COMP_2,..., COMP_N satisfy a determination condition set for detecting X-rays of a specific energy band
  • the pulse output COMP_D is activated.
  • the band determining unit 14 outputs one pulse output COMP_D when the energy band of the incident X-ray coincides with a determination sequence of, for example, a thermometer code or an unary method corresponding to the energy band to be detected.
  • the determination sequence set in the band determining section 14 may be set in any range. For example, if it is desired to detect X-rays having an energy band coming in between the first and fourth reference voltages, it may be set to a thermometer code sequence between 0111111 and 000011. Furthermore, it is also possible to set discontinuous decision sequences corresponding to discontinuous energy bands.
  • the band determination unit 14 inverts the pulse input of the comparison outputs applied according to the mode selection signal Polarity indicating the type of the charge output Q IN generated by the sensor unit 11 and the polarity of the voltage signal. Can be input.
  • the counter 15 counts the pulse output COMP_D output from the band judging unit 14 and outputs photon coefficient data.
  • the photon coefficient data corresponds to the number of times the X-ray corresponding to the specific energy band per unit time is incident, that is, the amount of X-rays having the corresponding energy band exposed to the photodiode region within the unit time.
  • an X-ray-only image having a specific energy band may be obtained.
  • FIG. 2 is a detailed circuit diagram illustrating an amplifier included in the X-ray read integrated circuit of FIG. 1.
  • the charge input QIN generated by the photodiode 21 of the sensor unit 11 by X-ray irradiation is input to the negative terminal of the operational amplifier 22.
  • the positive terminal of the operational amplifier 22 is grounded.
  • the feedback capacitor CF and the feedback resistor RF are connected between the output terminal of the operational amplifier 22 and the negative terminal.
  • the feedback capacitor CF accumulates the charge input QIN generated at the photodiode 21 of the sensor unit 11. Since the negative terminal of the operational amplifier 22 is virtually grounded with the positive terminal, the voltage generated across the feedback capacitor CF is calculated by the charge input QIN accumulated in the feedback capacitor CF. Appears at the output of the amplifier 22.
  • the feedback resistor RF determines a time constant for the feedback capacitor CF. For the next count, the feedback resistor RF exhausts the charge accumulated in the feedback capacitor CF in a time determined by the time constant.
  • FIG. 3 is a detailed circuit diagram illustrating a comparator included in the X-ray read integrated circuit of FIG. 1.
  • the comparator 13 includes a plurality of first, second, and N-th comparators 31, 32, and 33. Each of the comparators 31, 32, and 33 is commonly applied with the voltage output CSAOUT amplified by the amplifier 12 to the (+) terminal.
  • the first reference voltage VTH_1, the second reference voltage VTH_2, and the N th reference voltage VTH_N are respectively applied to the negative terminals of the comparators 31, 32, and 33.
  • the first comparator 31 compares the voltage output CSAOUT of the amplifier 12 to the first reference voltage VTH_1 of the highest level, so that the voltage output CSAOUT is greater than the first reference voltage VTH_1.
  • the second comparator 32 compares the voltage output CSAOUT of the amplifier 12 to the second reference voltage VTH_2 of the second highest level, so that the voltage output CSAOUT is greater than the second reference voltage VTH_2.
  • the activated second comparison output COMP_2 is output.
  • the N-th comparator 33 compares the voltage output CSAOUT of the amplifier 12 to the N-th reference voltage VTH_N of the lowest level, so that the voltage output CSAOUT is greater than the N-th reference voltage VTH_N. When high, the activated Nth comparison output COMP_N is output.
  • FIG. 4 is a detailed circuit diagram illustrating a band determiner included in the X-ray read integrated circuit of FIG. 1.
  • the band determining unit 14 is composed of N two-to-one multiplexers (MUXs) 41, 42, and 43 and one determining circuit 44.
  • MUXs two-to-one multiplexers
  • the comparison output of the comparator 13 has a pulse shape that varies depending on the type of charge
  • the band determiner 14 is activated with a consistent shape (ie, rising edge or falling edge regardless of the type of charge).
  • a mode selection signal for informing the output mode of the comparator 13 is introduced, and the comparison unit 13 is compared according to the mode selection signal. You can add a comparison output selection circuit that inverts the outputs or outputs them as is.
  • the N two-to-one multiplexers 41, 42, and 43 are left intact (when the mode select signal is 0) or inverted according to this mode select signal Polarity.
  • a comparison output selection circuit is outputted as a determination input signal (when the mode selection signal is 1).
  • the first two-to-one multiplexer 41 receives the first comparison output COMP_1 and the first inverted comparison output COMP_1F, respectively, and selectively determines one of the two inputs according to the mode selection signal Polarity. It outputs as an input signal DEC_1.
  • the second two-to-one multiplexer 42 receives the second comparison output COMP_2 and the second inverted comparison output COMP_2F, respectively, and selectively selects one of the two inputs according to the mode selection signal. Output as DEC_2).
  • the N-th two-to-one multiplexer 43 receives the N-th comparison output COMP_N and the first inverted comparison output COMP_NF, respectively, and selectively selects one of the two inputs according to the mode selection signal. Output as DEC_N).
  • the decision circuit 44 is a logic circuit for comparing and calculating the decision sequence and the pulse sequence of the decision input signals to determine whether the decision input signals satisfy the decision condition. If the sequence matches, pulse output (COMP_D) is activated and output.
  • the determination sequences that the determination circuit 44 bases on the determination may be determined and input to the determination circuit 44 according to which energy band X-rays are to be detected.
  • FIG. 5 is a circuit diagram illustrating in detail an X-ray read integrated circuit capable of detecting multiple energy bands according to another embodiment of the present invention.
  • the structure is similar to the X-ray read integrated circuit having the band determining unit 14 of FIG. 4, but does not include multiplexers in front of the determining circuit 44 of the band determining unit 14 of FIG. 4.
  • the decision circuit 44 of FIG. 4 receives the decision input signals
  • the comparison outputs of the comparator 13 can be directly applied to the decision logic.
  • the X-ray read integrated circuit of FIG. 5 may be preferable without adopting a mode selection signal and a comparison output selection circuit.
  • FIG. 6 is a waveform diagram when the X-ray read integrated circuit according to the exemplary embodiment of the present invention operates in the electronic detection mode.
  • the voltage output CSAOUT is generated in the amplifier 12.
  • the band determination unit 14 is set to detect only X-rays having an energy band whose voltage output CSAOUT of the amplifier 12 corresponds between the first reference voltage VTH_1 and the second reference voltage VTH_2. have.
  • the first X-ray photon has a relatively high energy band, so the voltage output CSAOUT exceeds the first and second reference voltages VTH_1 and VTH_2.
  • the mode selection signal Polarity means that the charge generated in the sensor unit 11 is electrons, which means that the comparison outputs output from the comparator 13 are active when the logic high is logic high.
  • the voltage output CSAOUT is higher than the second reference voltage VTH_2 and exceeds the first reference voltage VTH_1, the second comparison output COMP_2 and the first comparison output COMP_1 are together with the second determination input signal.
  • DEC_2 and the first determination input signal DEC_1 also become logic high. In this case, the determination circuit 44 determines that the X-ray photons are not between the first and second reference voltages, and does not output the activated pulse output COMP_D.
  • the second X-ray photon has an intermediate energy band such that the voltage output CSAOUT has a peak between the first and second reference voltages VTH_1 and VTH_2. Since the voltage output CSAOUT is higher than the second reference voltage VTH_2 but lower than the first reference voltage VTH_1, the first comparison output COMP_1 and the first determination input signal DEC_1 are set to logic low. The second comparison output COMP_2 and the second determination input signal DEC_2 are logic high. In this case, the determination circuit 44 determines that the energy band of the second X-ray photon is between the first and second reference voltages, and activates and outputs the pulse output COMP_D.
  • the third X-ray photon has a relatively low energy band so that the voltage output CSAOUT has a peak at a level lower than the first and second reference voltages VTH_1 and VTH_2. Since the voltage output CSAOUT is lower than the first and second reference voltages VTH_2, the first comparison output COMP_1 and the first determination input signal DEC_1 and the second comparison output COMP_2 and the second determination input signal. (DEC_2) all hold logic low. In this case, the determination circuit 44 determines that the energy band of the third X-ray photon is not between the first and second reference voltages, and keeps the pulse output COMP_D without inverting it.
  • the determination condition for outputting the pulse output COMP_D activated by the band determination unit 14 includes a determination input comparing a voltage output signal with a reference voltage corresponding to an upper limit of a specific energy band to be detected.
  • a pulse does not appear with respect to a signal (or a comparison output signal), and it can be said to be a condition in which a pulse appears in a determination input signal (comparative output signal) in which a reference voltage corresponding to the lower limit of a specific energy band and a voltage output signal are compared.
  • FIG. 7 is a waveform diagram when the X-ray read integrated circuit operates in the hole detection mode according to an embodiment of the present invention.
  • the voltage output CSAOUT is generated in the amplifier 12. Unlike FIG. 6, the voltage output increases in the negative direction.
  • the reference voltages also have lower values at higher energy bands.
  • the band determination unit 14 is set to detect only X-rays having an energy band whose voltage output CSAOUT of the amplifier 12 corresponds between the first reference voltage VTH_1 and the second reference voltage VTH_2. have.
  • the first X-ray photon has a relatively high energy band so that the voltage output CSAOUT is lower than the first and second reference voltages VTH_1 and VTH_2.
  • the mode selection signal Polarity means that the charge generated in the sensor unit 11 is a hole, which means that the comparison outputs output from the comparator 13 are active when the logic output is logic low.
  • the second comparison output COMP_2 and the first comparison output COMP_1 are logic low in order.
  • the second determination input signal DEC_2 and the first determination input signal DEC_1 are logic high. In this case, the determination circuit 44 determines that the X-ray photons are not between the first and second reference voltages, and does not output the activated pulse output COMP_D.
  • the second X-ray photon has an intermediate energy band such that the voltage output CSAOUT has an inverted peak between the first and second reference voltages VTH_1 and VTH_2. Since the voltage output CSAOUT is lower than the second reference voltage VTH_2 but higher than the first reference voltage VTH_1, the first comparison output COMP_1 is logic high and the first determination input signal DEC_1 is logic low. The second comparison output COMP_2 is logic low and the second determination input signal DEC_2 is logic high. In this case, the determination circuit 44 determines that the energy band of the second X-ray photon is between the first and second reference voltages, and activates and outputs the pulse output COMP_D.
  • the third X-ray photon has a relatively low energy band so that the voltage output CSAOUT has a reverse peak at a level higher than the first and second reference voltages VTH_1 and VTH_2. Since the voltage output CSAOUT is higher than the first and second reference voltages VTH_2, the first comparison output COMP_1 is logic high, the first determination input signal DEC_1 is logic low, and the second comparison output COMP_1) is also logic high, and the first determination input signal DEC_1 is also logic low. In this case, the determination circuit 44 determines that the energy band of the third X-ray photon is not between the first and second reference voltages, and keeps the pulse output COMP_D without inverting it.

Abstract

L'invention concerne un circuit intégré de lecture de rayons X qui comprend : une unité d'amplification qui convertit une quantité de charge, qui a été générée par une photodiode lorsque les rayons X étaient incidents, en un signal de sortie de tension et qui émet le signal converti ; une unité de comparaison qui compare le signal de sortie de tension à une tension de référence prédéfinie N, respectivement, et qui émet le signal de sortie de tension en qualité de signal de sortie comparatif N ; une unité de détermination de bande qui active un signal de sortie à impulsions si les signaux de sortie comparatifs répondent à une condition déterminée qui est établie afin de détecter un rayon X ayant une bande d'énergie spécifique ; et une unité de comptage qui compte le nombre d'impulsions du signal de sortie à impulsions et émet des données de comptage de photons.
PCT/KR2011/006834 2010-09-17 2011-09-16 Procédé de lecture et circuit de lecture pour détecter des rayons x à des bandes d'énergie prédéfinies, et capteur de rayons x utilisant ce procédé WO2012036494A2 (fr)

Applications Claiming Priority (2)

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KR1020100091737A KR101100580B1 (ko) 2010-09-17 2010-09-17 특정 에너지 대역의 검출이 가능한 엑스선 독출 방법, 독출 회로와 이를 이용한 엑스선 센서
KR10-2010-0091737 2010-09-17

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WO2012036494A2 true WO2012036494A2 (fr) 2012-03-22
WO2012036494A3 WO2012036494A3 (fr) 2012-06-21
WO2012036494A9 WO2012036494A9 (fr) 2012-09-07

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Citations (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JP2006101926A (ja) * 2004-09-30 2006-04-20 M & C:Kk 放射線検出装置、放射線画像診断装置、及び放射線画像の生成方法
US20090140155A1 (en) * 2007-12-03 2009-06-04 Canon Kabushiki Kaisha Radiation imaging apparatus and its driving method and program

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Publication number Priority date Publication date Assignee Title
SE0600056L (sv) 2006-01-13 2007-07-14 Tomas Unfors Arrangemang och anordning för avkänning och presentation av strålning

Patent Citations (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JP2006101926A (ja) * 2004-09-30 2006-04-20 M & C:Kk 放射線検出装置、放射線画像診断装置、及び放射線画像の生成方法
US20090140155A1 (en) * 2007-12-03 2009-06-04 Canon Kabushiki Kaisha Radiation imaging apparatus and its driving method and program

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WO2012036494A9 (fr) 2012-09-07
WO2012036494A3 (fr) 2012-06-21
KR101100580B1 (ko) 2011-12-29

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