WO2020055074A1

WO2020055074A1 - Radiation detector and radiographic method using same

Info

Publication number: WO2020055074A1
Application number: PCT/KR2019/011661
Authority: WO
Inventors: 신철우; 최진현; 유영기; 유병민
Original assignee: 주식회사 디알텍
Priority date: 2018-09-11
Filing date: 2019-09-09
Publication date: 2020-03-19
Also published as: KR102101766B1; KR20200029796A

Abstract

A radiation detector and a radiographic method using same, according to an embodiment of the present invention, detect the end of irradiation of radiation on the basis of the amount of charge read in at least one end detection pixel determined from among a plurality of pixels, and read an image output charge by scanning the plurality of pixels when the end of irradiation of the radiation is detected.

Description

Radiation detector and radiography method using the same

The present invention relates to a radiation detector and a radiographic method using the same, and more particularly, to a radiation detector for detecting termination of irradiation of radiation and a radiographic method using the same.

In general, a radiographic imaging apparatus includes a radiation generator that irradiates radiation to a subject and a radiation detector that detects radiation that has transmitted through the subject.

The radiographic imaging apparatus sequentially performs an operation of irradiating radiation from the radiation generating device to the radiation detector, an operation of absorbing radiation by the radiation detector, and a readout operation of reading charge generated by radiation irradiation from the radiation detector. do.

At this time, the radiation detector should detect the end of irradiation of radiation in order to effectively use it in the radiographic image without losing the irradiated radiation.

Conventionally, a lead-out operation is performed after a predetermined time has elapsed after the irradiation is not started without detecting the end of irradiation, or a lead-out operation is performed when the accumulated amount of charge generated by irradiation reaches a certain threshold. In this case, since the end of irradiation of the radiation is not known, the lead-out may not be performed for a predetermined time even if the lead-out is performed before the irradiation of the radiation is finished or the irradiation of the radiation is finished.

If the lead-out is performed before the irradiation ends, the radiation irradiated by the radiation detector after the lead-out starts cannot be used for the radiographic image, and if the irradiation is performed during the lead-out, the lead-out is performed. In the meantime, the charge generated by the irradiated radiation is also read out as lead-out, resulting in image defects in the radiographic image. That is, the readout is performed by sequentially scanning a plurality of pixels, and according to the scan order, the amount of charge generated by the irradiated radiation is changed during the readout, which is read as readout in each pixel, and thus the quality of the radiographic image is changed. Degradation or image defects occur.

In addition, if the lead-out is not performed for a predetermined period of time even after the irradiation of radiation is completed, noise such as dark current increases during a predetermined period during which the lead-out is not performed, resulting in a signal-to-noise ratio. ; SNR).

(Patent Document 1) Korean Patent Publication No. 10-2008-0104878

The present invention provides a radiation detector capable of detecting the end of irradiation of radiation without a complicated device and a radiographic method using the same.

The radiation detector according to an embodiment of the present invention includes a plurality of pixels in which charges generated by irradiation of radiation accumulate, and the plurality of pixels are connected to a plurality of gate lines and a plurality of data lines to be arranged in a matrix form. Radiation detection unit; A gate module for selecting at least one gate line among the plurality of gate lines; A lead-out module for selecting at least one data line among the plurality of data lines and reading charges accumulated in a pixel determined by the selected data line and the gate line selected through the gate module; A control unit for controlling the gate module and the readout module; And an irradiation termination detection unit for detecting termination of irradiation of the radiation based on the amount of charge read from at least one termination detection pixel determined from the plurality of pixels, wherein the control unit is configured to detect when the radiation termination is detected. The gate module and the readout module may be controlled to scan the plurality of pixels to read charges for image output.

When the irradiation end of the radiation is non-detected, the irradiation end detection unit may detect the termination of irradiation of the radiation based on the amount of charge newly read from the termination detection pixel.

The irradiation end detection unit may include: a charge amount value input unit for receiving an amount of charge read from the termination detection pixel; A reference value storage unit storing an end reference value for determining the end of irradiation of the radiation by comparing with the charge amount value input from the charge amount value input unit; And an end determination unit for determining the end of irradiation of the radiation by comparing the received charge amount value with the end reference value, and wherein the end determination unit is configured to terminate the irradiation of the radiation when the received charge amount value is less than or equal to the end reference value. It can be judged by detection.

The irradiation end detection unit further includes an end threshold setting unit for setting an end threshold value using the charge amount value input when the radiation amount is not irradiated from the charge amount value input unit, and the reference value storage unit sets the end threshold value. It can be stored as the end reference value.

The reference value storage unit may store, as the termination reference value, a value that is a predetermined ratio smaller than the charge amount value received during irradiation of the radiation from the charge amount value input unit.

The control unit controls the gate module and the readout module to empty the charge accumulated in the termination detection pixel, and the termination threshold setting unit inputs the charge amount value input unit after the charge accumulated in the termination detection pixel is emptied. The termination threshold may be set using the received charge value.

Further comprising: an irradiation start detection unit for detecting the start of irradiation of the radiation according to a comparison of the amount of charge read from at least one start detection pixel determined from the plurality of pixels and a preset start threshold, and the irradiation start detection unit further comprises: And a start threshold setting unit for setting the start threshold using the amount of charge read from the start detection pixel when the radiation is not irradiated, and the start threshold may be a different charge amount value from the end threshold.

The control unit controls the gate module and the readout module to perform a reset for the plurality of pixels that make the amount of charge of the plurality of pixels constant through application of a voltage, and the start threshold setting unit is configured for the plurality of pixels. After the reset is performed, the start threshold may be set using the amount of charge read from the start detection pixel.

When the irradiation start of the radiation is not detected, the control unit controls the gate module and the readout module to perform a reset for the plurality of pixels, and the irradiation start detection unit reads newly from the start detection pixel May detect the start of irradiation of the radiation again according to the comparison of the charge amount and the start threshold.

The irradiation end detection unit may include: a charge amount value input unit for receiving an amount of charge read from the termination detection pixel; An end threshold value setting unit for setting an end threshold value using the amount of charge received when the radiation is not irradiated by the charge amount input unit; And a charge amount value input from the charge amount value input unit and the termination threshold value, or a value obtained by subtracting the termination threshold value from a charge amount value input from the charge amount value input unit and a charge amount value previously input from the charge amount value input unit. And a termination determination unit for determining termination of irradiation of the radiation by comparing the value obtained by subtracting the termination threshold value, and wherein the termination determination unit is equal to or less than the termination threshold value of the charge amount input from the charge amount input unit When the value obtained by subtracting the termination threshold value from the charge amount input from the input unit is equal to or less than a predetermined ratio compared to the value obtained by subtracting the termination threshold value from the charge amount input from the charge amount input unit, the detection of radiation termination is detected. I can judge.

A radiographic method according to another embodiment of the present invention includes a plurality of pixels in which charges generated by irradiation of radiation accumulate, and the plurality of pixels are connected to a plurality of gate lines and a plurality of data lines to form a matrix. A radiation imaging method using a radiation detector including an array of radiation detectors, the method comprising: irradiating the radiation detector with the radiation detector using a radiation generator; Detecting an end of irradiation of the radiation based on an amount of charge read from at least one end detection pixel determined from the plurality of pixels; And scanning the plurality of pixels to read the charge for image output when the end of irradiation of the radiation is detected.

When the end of irradiation of the radiation is not detected, the process of detecting the end of irradiation of the radiation may be performed again.

The detecting of the end of irradiation of the radiation includes comparing the amount of charge read by the end detection pixel with a previously stored end reference value, and when the amount of charge read by the end detection pixel is less than or equal to the end reference value, the It can be judged by detection of completion of irradiation of radiation.

Setting an end threshold by reading charge from the end detection pixel when the radiation is not irradiated; And storing the set end threshold as the end reference value.

The method may further include storing a value smaller than a predetermined amount of charge read from the termination detection pixel as the termination reference value upon irradiation of the radiation.

The process of emptying the charge accumulated in the termination detection pixel may be further included. The setting of the termination threshold may be performed using the amount of charge read from the termination detection pixel after the emptying of the charge.

Setting a start threshold by reading charge from the start detection pixel determined among the plurality of pixels when irradiating the radiation; And detecting the start of irradiation of the radiation by comparing the amount of charge read from the start detection pixel with the start threshold, wherein the start threshold may be a different charge amount from the end threshold.

Further comprising the step of resetting the plurality of pixels to apply a voltage to the plurality of pixels so that the charge amount of the plurality of pixels is constant. The setting of the start threshold may further include resetting the plurality of pixels. Subsequently, it may be performed using the amount of charge read from the start detection pixel.

If the amount of charge read from the start detection pixel is smaller than the start threshold, it is determined as non-detection of the start of irradiation of the radiation, and the process of resetting the plurality of pixels and detecting the start of irradiation of the radiation is restarted. Can be done.

In the process of detecting the start of irradiation of the radiation, a process of resetting the plurality of pixels is performed and charges are accumulated for a first time, and in the process of detecting the end of radiation, the process of emptying the charge is performed. Charge may be accumulated and performed for a second time shorter than the first time.

In the process of detecting the end of irradiation of the radiation, the charge amount value read from the end detection pixel is compared with a preset end threshold value, or a value obtained by subtracting the end threshold value from the charge amount read from the end detection pixel. And comparing a value obtained by subtracting the termination threshold value to the amount of charge previously read from the termination detection pixel, and when the amount of charge read from the termination detection pixel is less than or equal to the termination threshold value, or at the termination detection pixel. If the value obtained by subtracting the termination threshold to the amount of charge read is less than a predetermined ratio compared to the value obtained by subtracting the termination threshold to the amount of charge previously read by the termination detection pixel, it may be determined as detection of the end of irradiation of the radiation. have.

The radiation detector according to an embodiment of the present invention detects the end of irradiation of radiation based on the amount of charge read from the determined end detection pixel among a plurality of pixels of the radiation detection unit, and thus a gate module and a readout using a control unit without a complicated device. Through the control of the module, it is possible to easily detect the end of irradiation. In addition, by detecting the end of the irradiation of radiation and reading the charge for image output, it is possible to effectively use the radiation image without losing the irradiated radiation, and to solve the conventional problem that the quality of the radiation image is deteriorated or image defects occur. You can.

And the process of reading the charge for image output can be started in accordance with the end of irradiation, so that the cycle time of radiography can be optimized according to the irradiation conditions, and the battery consumption for radiography can be optimized. Can be achieved. Accordingly, it is possible to reduce a reduction in the efficiency of equipment operation, and to suppress or prevent factors that may cause a decrease in the quality of a radiographic image due to a user's lack of operation, such as incorrectly setting a setting value related to irradiation. It may alleviate the patient's pain due to the time required.

In the case of mammography, the irradiation time is relatively long, and the longest time reaches 5 seconds, and when the irradiation time is set in accordance with this time, the time required for radiographic imaging is very long, deteriorating equipment operation efficiency and radiographic images. Poor quality can have a serious impact.

On the other hand, since detection conditions such as whether radiation is irradiated and whether reset is performed are different in detecting the start of irradiation of radiation and the end of irradiation of radiation, the start threshold and the end threshold are set in different ways according to each detection situation. Thus, it is possible to accurately detect the start and end of irradiation. In addition, since the irradiation end of the radiation is detected by a pixel of the radiation detection unit rather than a separate device, detection errors due to vibration may be reduced.

1 is a block diagram showing the configuration of a radiation detector according to an embodiment of the present invention.

Figure 2 is a conceptual diagram for explaining the connection of the radiation detector and the gate module and the lead-out module according to an embodiment of the present invention.

3 is a conceptual diagram for explaining a driving process of the radiation detector according to an embodiment of the present invention.

Figure 4 is a conceptual diagram for explaining the comparison of the amount of charge read and the reference end value according to an embodiment of the present invention.

5 is a conceptual diagram illustrating a process of resetting and reading electric charges according to an embodiment of the present invention.

6 is a flowchart illustrating a radiographic method according to another embodiment of the present invention.

7 is a flow chart illustrating a process of comparing the amount of charge read and the reference end value according to another embodiment of the present invention.

Hereinafter, embodiments of the present invention will be described in more detail with reference to the accompanying drawings. However, the present invention is not limited to the embodiments disclosed below, but will be implemented in various different forms, and only the present embodiments allow the disclosure of the present invention to be complete, and the scope of the invention to those skilled in the art is completely It is provided to inform you. In the description, the same reference numerals are assigned to the same components, and the drawings may be exaggerated in size in order to accurately describe embodiments of the present invention, and the same reference numerals in the drawings refer to the same elements.

1 is a block diagram showing the configuration of a radiation detector according to an embodiment of the present invention, Figure 2 is a conceptual diagram for explaining the connection of the radiation detector and the gate module and the lead-out module according to an embodiment of the present invention.

1 and 2, the radiation detector 100 according to an embodiment of the present invention includes a plurality of pixels 111 in which charges generated by irradiation of radiation accumulate, and the plurality of pixels 111 ) Is connected to the plurality of gate lines 121 and the plurality of data lines 131, a radiation detector 110 arranged in a matrix form; A gate module 120 for selecting at least one gate line 121 among the plurality of gate lines 121; At least one data line 131 among the plurality of data lines 131 is selected and accumulated in the pixel 111 determined by the selected data line 131a and the gate line 121a selected through the gate module. A lead-out module 130 for reading electric charges; A control unit 140 for controlling the gate module 120 and the readout module 130; And an irradiation termination detection unit 150 for detecting termination of irradiation of the radiation based on the amount of charge read from at least one termination detection pixel 111a determined from the plurality of pixels 111.

The radiation detector 110 may include a plurality of pixels 111 in which charges generated by irradiation of radiation accumulate, and the plurality of pixels 111 may include a plurality of gate lines 121 and a plurality of data lines 131. ) May be arranged in a matrix form. In this case, the plurality of gate lines 121 and the plurality of data lines 131 may cross each other. When radiation is irradiated to the radiation detector 110, charges may be generated by the irradiated radiation, and charges may be accumulated in each pixel 111 in proportion to the radiation dose. The radiation detector 110 may have a panel shape divided into a plurality of pixels 111 arranged in a matrix form, and each pixel may include a thin film transistor (TFT).

Here, the radiation detector 100 may be a direct method of generating a direct charge using a material (for example, a photoconductive material) that is irradiated with radiation to generate charge, and convert the radiation into visible light It may also be an indirect method that converts radiation irradiated by a material (for example, a scintillator) into visible light and indirectly generates charge through a photodiode. When the radiation detector 100 is an indirect method, the radiation detection unit 110 receives the irradiated radiation for each pixel and emits light, while receiving a scintillator that outputs visible light photons and receives the output visible light photons. Thus, it may include a photodiode (or photodiode) for generating charge (or electrical signal) and a reservoir (for example, a storage capacitor) for storing the generated charge. On the other hand, it is also possible to use a photodiode capable of storing charge.

The gate module 120 may be configured to select at least one gate line 121 among the plurality of gate lines 121, and may control the selection of the gate line 121. For example, when the gate line 121 is selected from the gate module 120, the storage elements (eg, pixel electrodes, storage capacitors, etc.) on the selected gate line 121 may be turned on. When the reservoirs on the gate line 121 are turned on, charges accumulated in the reservoir can be moved to the data line 131. In this case, the storage element can be turned on by applying a voltage to the gate of the first transistor connected to the storage element, and the gate module 121 applies the voltage to the gate line 121. It may be to choose.

The readout module 130 selects at least one data line 131 among the plurality of data lines 131 and is determined by the selected data line 131a and the gate line 121a selected through the gate module 120. It may be configured to read the charge accumulated in the pixel (or corresponding to the point where the selected data line and the gate line selected in the gate module intersect). For example, when the reservoir is turned on and the charge accumulated in the reservoir moves to the data line 131, the lead-out module 130 selects the data line 131 to which the charge has been moved and the charge is moved. Charges can be read from the data line 131. At this time, the lead-out module 130 may convert the read charge into an electrical signal. Here, a method of selecting the data line 131 may use a selection switch (not shown) connected to the data line 131, and a selection switch (not shown) is connected to the data line 131 in series. It may be composed of transistors. When the selection switch (not shown) is composed of a transistor, the readout module 130 turns on the transistor through application of a voltage to allow electric charge to flow through the data line 131, thereby causing the data line 131 to be transferred. Can be selected. However, the method for selecting the data line 131 is not particularly limited.

The control unit 140 may be configured to control the gate module 120 and the lead-out module 130, and may be responsible for overall control of the radiation detector 100. The control unit 140 controls on / off of each of the plurality of pixels 111 (that is, the storage of each of the plurality of pixels) through control of the gate module 120 and the readout module 130. It can be controlled, and the pixel 111 can be turned off to accumulate charge in the pixel 111, and the pixel 111 can be turned on to output charge from the pixel 111. . For example, the control unit 140 may enable all of the plurality of pixels 111 or at least one specific pixel 111 to be selected and turned on and output from the selected pixel 111. The gate module 120 and the readout module 130 may be controlled to read electric charges through the data line 131.

The irradiation end detection unit 150 may be configured to detect (or sense) the termination of irradiation of the radiation based on the amount of charge read from at least one termination detection pixel 111a determined among the plurality of pixels 111. For example, when the radiation is not irradiated, the lead-out module 130 determines the termination reference value using the amount of charge read from the termination detection pixel 111a, and reads it from the determined termination reference value and termination detection pixel 111a. The (or currently read) charge amount can be compared to detect the end of irradiation of the radiation. At this time, when the radiation is not irradiated, the lead-out module 130 may determine a value equal to the amount of charge read from the termination detection pixel 111a as the termination reference value, and when irradiating the radiation to reduce detection errors The readout module 130 may determine a value larger or smaller by a predetermined ratio than the amount of charge read from the termination detection pixel 111a as the termination reference value.

In addition, the control unit 140 may control the gate module 120 and the lead-out module 130 to scan a plurality of pixels 111 and read charges for image output when the irradiation of the radiation is detected. When the end of irradiation of the radiation is detected, a plurality of pixels 111 can be scanned immediately, charges for image output can be read, and radiation images can be generated using the charges for the image output. Here, the charge for image output may be a charge used to generate a radiographic image, or may be a charge generated and accumulated by irradiation of the radiation until the irradiation starts and ends. A method of scanning a plurality of pixels 111 may perform a progressive scan sequentially scanning from the top left to the bottom right, and for this, a line moving unit (not shown) such as a shift register (not shown) You can also use At this time, the time to scan one gate line 121 may be a very short time (for example, about 196 ms). Meanwhile, in the termination detection pixel 111a in which the amount of charge is lost in order to detect the termination of irradiation of the radiation, charges may or may not be read while scanning the plurality of pixels 111.

In the present invention, by determining (or selecting) at least one of the plurality of pixels 111 as the end detection pixel 111a, the charge is read only from the end detection pixel 111a to detect the end of irradiation of the radiation, and the remaining pixels are read. In the field, charges for the image output generated by irradiation of the radiation may be accumulated, and radiation images may be generated using the charges for image output accumulated in the remaining pixels.

Meanwhile, the radiation detector 100 of the present invention may further include a data interface 173 for transmitting the charge data for image output to a computer. The data interface 173 is configured to arrange the charge data for image output in the form of a frame after obtaining the charge for image output read through the scan of the plurality of pixels 111 by detecting the end of irradiation of the radiation. Personal Computer; PC). Here, the analog data may be converted into digital data and transmitted to the data interface 173, and the radiation detector 100 may further include an analog-to-digital converter 172 that converts analog data into digital data.

3 is a conceptual diagram for explaining a driving process of the radiation detector according to an embodiment of the present invention, the irradiation start detection indicates the detection operation (Automatic Exposure Detection; AED) of the radiation start, and the irradiation end detection of the radiation It indicates the detection operation (Adaptive exposure Window Control) AWC.

Referring to FIG. 3, when the irradiation end of the radiation is not detected, the irradiation end detection unit 150 may detect the termination of irradiation of the radiation again based on the amount of charge newly read from the termination detection pixel 111a. In addition, the control unit 140 may control the gate module and the readout module to read electric charges again from the termination detection pixel. The irradiation end detection unit 150 may detect the termination of irradiation of the radiation again without a reset when the irradiation termination of the radiation is non-detected, and the irradiation of the radiation is terminated until the termination of irradiation of the radiation is detected. The detection of can be repeated. At this time, the detection of the end of irradiation of the radiation may be repeated at a predetermined period, the charge is read and emptied, and the charge accumulated during a predetermined period (or time) may be repeatedly read at the termination detection pixel 111a.

In addition, the irradiation end detection unit 150 includes a charge amount value input unit 151 for receiving a charge amount value read from the end detection pixel 111a; A reference value storage unit 152 in which an end reference value for determining termination of irradiation of the radiation is stored in comparison with the charge amount value input from the charge amount value input unit 151; And an end determination unit 153 for comparing the received amount of charge with the end reference value to determine the end of irradiation of the radiation. The charge amount value input unit 151 may be configured to receive the charge amount value read from the termination detection pixel 111a, and by receiving the charge amount value read from the termination detection pixel 111a, determine the termination reference value and store it It is possible to compare the amount of charge input to detect the end of irradiation with the radiation and the end reference value. The charge amount value input unit 151 may be connected to the reference value storage unit 152 and the termination determination unit 153, and transfer (or transfer) the received charge amount value to the reference value storage unit 152 and / or the termination determination unit 153. )can do.

The reference value storage unit 152 may store an end reference value for determining the end of irradiation of the radiation by comparing with the charge amount value received from the charge amount value input unit 151. The termination reference value may be a value that is compared with a charge amount value input from the charge amount value input unit 151 to determine the end of irradiation of the radiation, and when the radiation is not irradiated, the lead-out module 130 terminates the detection pixel 111a ) May be the same value as the amount of charge read in, or may be a value that is larger or smaller by a predetermined ratio than the amount of charge read from the termination detection pixel 111a when the lead-out module 130 is irradiated with the radiation to reduce detection errors. .

The termination determination unit 153 may be configured to determine the end of irradiation of the radiation by comparing the received charge amount value with the termination reference value. The termination determination unit 153 may determine the termination of irradiation of the radiation by comparing the current (or at the time of determination) the amount of charge input from the amount of charge input unit 151 with the termination reference value.

At this time, the termination determination unit 153 may determine the detection of the termination of irradiation of the radiation when the received charge amount value is less than or equal to the termination reference value, and when the received charge amount value is greater than the termination reference value, It can be judged as the non-detection of the investigation. Since the amount of charge accumulated in the termination detection pixel 111a is proportional to the irradiation amount of radiation, when radiation is irradiated to a plurality of pixels 111 of the radiation detection unit 110 and irradiation of radiation ends, the end detection pixel 111a reads it. The amount of charge input is reduced, so that the amount of charge read from the current termination detection pixel 111a is less than or equal to the termination reference value. Using this, it is possible to detect (or judge) the end of irradiation of the radiation.

In addition, the irradiation end detection unit 150 may further include an end threshold setting unit 154 for setting an end threshold value using the amount of charge received when the radiation is not irradiated from the charge amount input unit 151. . The termination threshold setting unit 154 may be configured to set the termination threshold value using the amount of charge input when the radiation amount is not irradiated from the amount of charge input unit 151. The amount of charge read from the termination detection pixel 111a upon non-irradiation of the radiation may be a dark current accumulated (or accumulated) in the termination detection pixel 111a, and the termination threshold is the termination detection pixel 111a ) May be selected as a value less than or equal to the amount of charge read. Here, in order to reduce detection errors, the termination threshold value may be selected as a value larger or smaller than a predetermined amount of charge read from the termination detection pixel 111a when irradiating the radiation, and the predetermined ratio may be a radiation detector ( It may be appropriately determined according to the specifications of 100) and the radiographic environment. For example, when the amount of charge read from the termination detection pixel 111a when the radiation is not irradiated is 0.1 pC, the termination threshold may be 0.3 pC. To avoid detection errors due to vibration, vibration, etc. Even if an error in the amount of charge occurs, the amount of charge read from the end detection pixel 111a at the time of irradiation of the radiation must be greater than 0.3 pC, and even when an error due to vibration occurs, the end detection pixel at the time of non-irradiation of the radiation ( The charge amount read in 111a) should be 0.3 pC or less. At this time, it may be desirable to set the termination threshold in the standby mode of the radiation detector 100 before entering the imaging mode of the radiation detector 100 performing radiation imaging, and the radiation on which the radiation is not irradiated The termination threshold may be reset whenever the termination of the irradiation is not detected.

4 is a conceptual diagram for explaining a comparison between the amount of charge read and a reference end value according to an embodiment of the present invention, FIG. 4 (a) shows a comparison with an end threshold, and FIG. 4 (b) Indicates a comparison with a value that is a predetermined ratio smaller than the value of the amount of charge read during irradiation of radiation. Here, the irradiation start detection represents a detection time point at the start of irradiation of the radiation, the irradiation end non-detection represents a time point at which the irradiation end of the radiation is not detected, and the irradiation end detection represents a detection time point at the end of the irradiation of the radiation.

Referring to FIG. 4, the reference value storage unit 152 may store the termination threshold value as the termination reference value. The termination threshold value may be stored as the termination reference value, and compared with the current amount of charge input from the current amount of charge input unit 151 to determine the end of irradiation of the radiation. Through this, it is possible to detect the end of irradiation of the radiation.

For example, as shown in FIG. 4A, when the amount of charge read from the current end detection pixel 111a is greater than the end threshold after detecting the start of irradiation of the radiation, non-detection of the end of the irradiation of the radiation is not detected. It is determined that the end of irradiation of the radiation may be detected again, and if the amount of charge read from the end detection pixel 111a is less than the end threshold after repeating the detection of the start of irradiation of the radiation, the end of irradiation of the radiation is detected. You can judge by.

Also, the reference value storage unit 152 may store, as the termination reference value, a value that is a predetermined ratio smaller than the charge amount value received during irradiation of the radiation by the charge amount value input unit 151. Through this, when the radiation is irradiated, a value smaller than a predetermined amount of charge read from the termination detection pixel 111a is used as the termination reference value, so that it can be compared with the current amount of charge input from the current charge amount input unit 151, and radiation is irradiated. When the irradiation of radiation ends, the amount of charge read from the end detection pixel 111a decreases, so a value smaller than the amount of charge read by the end detection pixel 111a can be used as the termination reference value. At this time, when the radiation is irradiated, the amount of charge read from the termination detection pixel 111a (that is, the amount of charge received from the charge amount input unit) is the amount of charge read from the termination detection pixel 111a before (or at the time of the previous determination). In the case of detecting the end of irradiation of the radiation again, the amount of charge read from the end detection pixel 111a for detecting the end of irradiation of the previous radiation is added to the end reference value or the end reference value is detected at the end The amount of charge read from the pixel 111a can be updated.

Here, the small value of the predetermined ratio may be a value as small as the predetermined predetermined ratio (eg, about 70%) of the amount of charge read from the termination detection pixel 111a upon irradiation of the radiation. For example, when the predetermined ratio is 70%, the small value of the predetermined ratio may be a value as small as 70% of the amount of charge read from the termination detection pixel 111a upon irradiation of the radiation, and upon irradiation of the radiation A value smaller than a predetermined amount of charge read by the termination detection pixel 111a may be a value that is 30% of the amount of charge read by the termination detection pixel 111a upon irradiation of the radiation.

Further, the small value of the predetermined ratio may be determined by subtracting (or subtracting) the termination threshold from the amount of charge read from the termination detection pixel 111a upon irradiation of the radiation, and terminates upon irradiation of the radiation It may be a value as small as a predetermined ratio (for example, about 50%) of a value obtained by subtracting the termination threshold from the amount of charge read from the detection pixel 111a. For example, when the predetermined ratio is 60%, the small value of the predetermined ratio is as small as 60% of a value obtained by subtracting the termination threshold from the amount of charge read from the termination detection pixel 111a upon irradiation of the radiation. A value that may be a value and a predetermined ratio smaller than the amount of charge read from the end detection pixel 111a upon irradiation of the radiation is obtained by subtracting the end threshold from the amount of charge read from the end detection pixel 111a upon irradiation of the radiation It may be the sum of the value that is 40% of the value and the end threshold. At this time, the predetermined ratio may be determined by the ratio of the termination threshold and the value obtained by subtracting the termination threshold from the amount of charge read by the termination detection pixel 111a upon irradiation of the radiation and the predetermined ratio.

When the predetermined ratio small value is determined by subtracting the termination threshold value from the amount of charge read from the termination detection pixel 111a upon irradiation of the radiation, the irradiation intensity (or irradiation amount) of the radiation is small and the radiation Set the termination reference value that can effectively detect the end of irradiation of the radiation while having a value greater than the termination threshold even when the difference between the amount of charge read from the termination detection pixel 111a and the termination threshold is not large at the time of irradiation (Or save).

On the other hand, a value that is a predetermined percentage smaller than the amount of charge read from the termination detection pixel 111a at the previous determination time and a value that is a certain percentage smaller than the amount of charge read from the termination detection pixel 111a at the determination time before two cycles can be stored as the termination reference value. From the fourth judgment point, a value that is a predetermined percentage smaller than the amount of charge read from the termination detection pixel 111a at the previous determination time and a value that is a certain percentage smaller than the amount of charge read from the termination detection pixel 111a before the determination of two cycles is updated. Can.

At the first determination point, the amount of charge read from the current termination detection pixel 111a may be compared with the termination threshold value, and at the second determination point, the amount of charge read from the current termination detection pixel 111a may be compared to the termination threshold value and / or At a previous determination point, a predetermined ratio smaller than the amount of charge read from the termination detection pixel 111a can be compared, and at the third or higher determination point, the amount of charge read from the current termination detection pixel 111a is determined by the termination threshold and the previous determination point. In comparison, the value may be compared with a value that is a predetermined percentage smaller than the amount of charge read from the termination detection pixel 111a and / or a value that is a certain percentage smaller than the amount of charge read from the termination detection pixel 111a at the time of determination two cycles earlier. At this time, the termination threshold value may be compared first to the amount of charge read from the current termination detection pixel 111a, and a value smaller than a predetermined amount of charge read from the termination detection pixel 111a at a previous determination time, determined two cycles earlier The amount of charge read from the current end detection pixel 111a may be compared with the value of a predetermined ratio smaller than the amount of charge read from the end detection pixel 111a at a time.

The amount of charge read from the current end detection pixel 111a is equal to or less than the end threshold, a value smaller than a predetermined percentage of the amount of charge read from the end detection pixel 111a at the previous determination time, and / or is detected at the time of determination two cycles earlier. When the amount of the charge read from the pixel 111a is less than or equal to a predetermined ratio, it can be determined as detection of the end of irradiation of the radiation.

For example, as illustrated in FIG. 4B, when the amount of charge read from the current end detection pixel 111a is greater than the end threshold after detecting the start of irradiation, non-detection of the end of irradiation of the radiation is not detected. It is possible to detect the end of irradiation of the radiation again, and repeat the detection of the start of irradiation of radiation, and then the amount of charge read from the end detection pixel 111a is transferred (for example, before the determination time or two cycles) At a point in time), when it is equal to or smaller than a predetermined ratio smaller than the amount of charge read from the end detection pixel 111a, it may be determined as detection of the end of irradiation of the radiation.

On the other hand, the irradiation end detection unit 150 includes a charge amount value input unit 151 for receiving a charge amount value read from the end detection pixel 111a; An end threshold value setting unit 154 for setting an end threshold value using the amount of charge received when the radiation amount is not irradiated from the charge amount input unit 111a; And a charge amount value input from the charge amount value input unit 151 and the termination threshold value, or a value obtained by subtracting the termination threshold value from the charge amount value input from the charge amount value input unit 151 and a charge amount value input unit 151. ) May include an end determination unit 153 for determining the end of irradiation of the radiation by comparing a value obtained by subtracting the end threshold value with the amount of charge input from the end value, and the end determination unit 153 is the charge amount value input unit When the charge amount value received in (151) is less than or equal to the termination threshold value, or a value obtained by subtracting the termination threshold value from the charge amount value input from the charge amount value input unit 151 is previously received by the charge amount value input unit 151 When the charge amount value is equal to or less than a predetermined ratio compared to a value obtained by subtracting the termination threshold value, it may be determined as detection of the termination of irradiation of the radiation.

When comparing with the termination threshold value, the termination determination unit 153 uses the charge amount value input from the charge amount value input unit 151 as a comparison target, so that the charge amount value received from the charge amount input unit 151 is the termination threshold value. In the following cases, it can be judged as detection of the end of irradiation of the radiation.

And the termination determination unit 153 is different from the comparison target to the value of the charge amount input from the charge amount value input unit 151 by subtracting the termination threshold value and the charge amount value previously input from the charge amount value input unit 151 A value obtained by subtracting the termination threshold value may be compared, and a value obtained by subtracting the termination threshold value from a charge amount value input from the charge amount value input unit 151 is compared to a charge amount value previously input from the charge amount value input unit 151. When the end threshold is less than or equal to a predetermined ratio compared to the subtracted value, it may be determined as detection of the end of irradiation of the radiation. Accordingly, when the irradiation intensity of the radiation is small and the difference between the amount of charge read from the end detection pixel 111a and the end threshold is not large when the radiation is irradiated, the amount of charge received from the charge amount input unit 151 The termination of irradiation of the radiation that is not detected by comparison of the termination threshold can also be effectively detected.

In addition, the control unit 140 may control the gate module 120 and the readout module 130 to empty the charge accumulated in the termination detection pixel 111a, and the termination threshold setting unit 154 may include the termination detection pixel ( After the charge accumulated in 111a) is emptied, the termination threshold value may be set using the charge amount value input from the charge amount value input unit 151. The control unit 140 may control the gate module 120 and the readout module 130 to empty the charge accumulated in the termination detection pixel 111a, and from the termination detection pixel 111a through the data line 131 The accumulated charge may be emptied, and the end detection pixel 111a may be emptied before the end threshold setting unit 154 sets the end threshold. At this time, the charge accumulated in the termination detection pixel 111a may be read to obtain a charge amount value, and the charge accumulated in the termination detection pixel 111a may be output and removed through the data line 131 without obtaining the charge amount value. You may.

For example, when the charge amount value is obtained, charges read from the termination detection pixel 111a may be input to an operational amplifier (Op Amp, 132), etc., or if the charge amount value is not obtained, a ground line, etc. Grounding may remove the charge output through the data line 131, and may quickly cause the termination detection pixel 111a to be emptied by not going through an unnecessary process of obtaining a charge amount value.

The termination threshold setting unit 154 may set the termination threshold using the amount of charge received from the charge amount input unit 151 after emptying the charge accumulated in the termination detection pixel 111a, and the termination detection pixel ( By outputting the charge accumulated in 111a) and accumulating charges as much as the period at which detection of radiation termination is performed after the termination detection pixel 111a is emptied, the amount of charge read from the termination detection pixel 111a is used to The termination threshold can be set.

In the case of detecting the end of irradiation of radiation, since irradiation of radiation is in progress, if a reset is performed to make the charge amount of the plurality of pixels 111 constant, radiation is irradiated to remove the accumulated charge amount. Alternatively, since the unnecessary amount of charge is increased in each of the plurality of pixels 111, it is difficult to detect the end point of accurate irradiation, and quality of the radiographic image may be deteriorated or distortion may occur.

Accordingly, the termination threshold setting unit 154 may set the termination threshold using the amount of charge received from the charge amount input unit 151 after emptying the charge accumulated in the termination detection pixel 111a without reset.

The radiation detector 100 according to the present invention is configured to detect the start of irradiation of the radiation according to a comparison of a charge amount read from at least one start detection pixel 111b determined from a plurality of pixels 111 and a preset start threshold value. It may further include; the irradiation start detection unit 160; The irradiation start detection unit 160 detects (or detects) the start of irradiation of the radiation according to a comparison of the amount of charge read from at least one start detection pixel 111b determined from the plurality of pixels 111 and a preset start threshold. Can be configured to. For example, when the radiation is not irradiated, a start threshold is set by the amount of charge read by the lead-out module 130, and read (or currently read) from the set start threshold and start detection pixel 111b. If the amount of charge read from the start detection pixel 111b by comparing the amount of charge is greater than or equal to the start threshold, it can be determined as the start of irradiation of the radiation (or detection of the start of irradiation of the radiation), and the start detection pixel 111b If the amount of charge read is smaller than the starting threshold, it can be determined as non-detection of the start of irradiation of the radiation.

In addition, the irradiation start detection unit 160 may include a start threshold setting unit 161 for setting the start threshold using the amount of charge read from the start detection pixel 111b when the radiation is not irradiated. The start threshold setting unit 161 may set the start threshold using the amount of charge read from the start detection pixel 111b when the radiation is not irradiated, and when the radiation is not irradiated, the start detection pixel 111b ) May be a dark current accumulated in the start detection pixel 111b, and the start threshold may be selected as a value greater than the amount of charge read in the start detection pixel 111b. Here, the start threshold may be selected as a value greater than a predetermined amount of charge read from the start detection pixel 111b when irradiating the radiation to reduce the detection error of the start of irradiation, and the predetermined ratio is radiation It can be appropriately determined according to the specifications of the detector and the radiographic environment. For example, when the amount of charge read from the start detection pixel 111b at the time of non-irradiation of the radiation is 0.1 pC, the start threshold may be 0.5 pC, and in order to avoid detection errors due to vibration or the like, due to vibration or the like Even if an error occurs, the amount of charge that can be read from the start detection pixel 111b at the time of irradiation of the radiation should be 0.5 pC or more, and even if an error due to vibration occurs, the start detection pixel 111b at the time of non-irradiation of the radiation ) Must be less than 0.5 pC.

On the other hand, in the conventional radiation detector, friction or contact with a patient is frequently performed for movement or inspection, and unintended automatic exposure due to changes in the state of the light detector or the radiation detector due to vibration generated by the friction or contact. A problem occurs in that a request signal is generated. However, in the present invention, since the start threshold value is set by reflecting an error due to vibration or the like, the detection error at the start time of irradiation can be reduced.

The start threshold value may be a different charge amount value from the end threshold value. The charge for image output generated and accumulated by irradiation of the radiation is accumulated after reset so as to reduce noise such as dark current when generating a radiation image, and must be in a reset state at the time of detection of the start of irradiation. The start threshold can also be set after reset. Since the end threshold need only check the amount of charge accumulated during a predetermined period (or time), it can be set after the charge accumulated in the end detection pixel 111a is emptied without a separate reset. Accordingly, the start threshold value is different from the end threshold value, and may have different charge amount values.

5 is a conceptual diagram for explaining a process of resetting and retrieving charges according to an embodiment of the present invention, FIG. 5 (a) shows a reset execution state, and FIG. 5 (b) reads charges Indicates the state.

Referring to FIG. 5, the control unit 140 may reset the gate module 120 and the lead-out module 130 to reset the plurality of pixels 111 that uniformize the amount of charge of the plurality of pixels 111 through application of a voltage. ), And the start threshold setting unit 161 may set the start threshold using the amount of charge read from the start detection pixel 111b after reset of a plurality of pixels 111 is performed. have. The control unit 140 may control the gate module 120 and the lead-out module 130 to perform a reset for the plurality of pixels 111 that constants the amount of charge of the plurality of pixels 111 through application of a voltage, , Before the start threshold setting unit 161 sets the start threshold, resets the plurality of pixels 111 so that the charge amount of the plurality of pixels 111 becomes constant, and the irradiation of the radiation It can be made into a state in which the charge for image output generated and accumulated by can be accumulated.

For example, the readout module 130 amplifies the difference between the charge read into each data line 131 for each data line 131 and the reference potential V _ref from the reference power supply 171 ( Op Amp, 132, and a variable capacitor (Variable Capacitor, 133) and a reset switch 134 connected in parallel with the operational amplifier 132. The operational amplifier (Op Amp, 132) can amplify the difference between the charge read into the data line 131 and the reference potential (V _ref ) from the reference power supply 171, and includes two inverting input terminals and a non-inverting input terminal. It may include an input terminal and one output terminal. The inverting input terminal of the operational amplifier 132 is connected to the data line 131 so that charges read into the data line 131 can be supplied, and the reference power source 171 is supplied to the non-inverting input terminal of the operational amplifier 132. The reference voltage V _ref from the reference power supply 171 may be connected to it.

The variable capacitor 133 and the reset switch 134 may be connected in parallel between the inverting input terminal and the output terminal of the operational amplifier 132, and the variable capacitor 133 changes the capacitor value to change the operational value of the operational amplifier 132. The amplification factor can be changed, and a reset switch 134 can be used to reset each pixel 111.

When the reset switch 134 in the readout module 130 is closed, the output terminal of the operational amplifier 132 may be connected to the data line 131, and the data line from the output terminal of the operational amplifier 132 A voltage may be applied to each pixel 111 through 131 to make each pixel 111 a reference voltage V _ref . That is, a voltage that is a difference between a voltage input to the non-inverting input terminal of the operational amplifier 132 and a voltage input to the inverting input terminal of the operational amplifier 132 is output to the output terminal of the operational amplifier 132, and the operational amplifier is output. A voltage obtained by subtracting the voltage due to the charge read into the data line 131 from the reference voltage V _ref input to the non-inverting input terminal of 132 is applied to each pixel 111 so that each pixel 111 is a reference voltage. (V _ref ). At this time, charges accumulated in each pixel 111 may be read and removed through the data line 131.

Accordingly, after selecting all the gate lines 121 through the gate module 120, closing all reset switches 134 connected to each data line 131 to apply voltage to the plurality of pixels 111, thereby forming a plurality of pixels 111 ) Can all be made to the reference voltage V _ref , and accordingly, the charge amount of the plurality of pixels 111 may be constant.

Meanwhile, when the reset switch 134 is opened in the readout module 130, charges read into the data line 131 may be stored in the variable capacitor 133 to obtain a charge amount value.

The start threshold setting unit 161 may set the start threshold using the amount of charge read from the start detection pixel 111b after the reset of the plurality of pixels 111 is performed, and the plurality of pixels 111 ) After the reset is performed and the start detection pixel 111b becomes a state in which the charge for image output can be accumulated, the charge is accumulated as much as the period at which the start of irradiation of the radiation is detected to start the detection pixel 111b. The starting threshold may be set using the amount of charge read from.

As described above, the start threshold and the end threshold are set in different ways, and each charge value may vary depending on whether reset is performed, and the start threshold for accurate detection of the end of irradiation of the radiation. It may be desirable to detect the termination of irradiation of the radiation through another of the termination thresholds.

Meanwhile, the end detection pixel 111a and the start detection pixel 111b may use pixels having the same location (ie, the same pixel). In this case, since the start detection pixel 111b is read while detecting the start of irradiation of the radiation with the start detection pixel 111b, the end detection pixel 111a can be emptied naturally, and the end detection pixel 111a is separately You may not want to perform the process of making this empty. In addition, since the amount of charge is lost for the detection of the end of irradiation and the start of irradiation, the end detection pixel 111a and the start detection pixel 111b correct the lost amount of charge data through an image data correction unit (not shown). Therefore, when the end detection pixel 111a and the start detection pixel 111b are pixels at the same position, the number of pixels to be corrected can be reduced, so that the amount of charge data can be easily corrected, and more pixels 111 The charge for the image output can be read in, thereby improving the quality of the radiographic image.

In addition, when the irradiation start of the radiation is not detected, the control unit 140 may control the gate module 120 and the lead-out module 130 to perform a reset on the plurality of pixels 111, and the irradiation start detection unit The 160 may detect the start of irradiation of the radiation again according to a comparison of the amount of charge newly read from the start detection pixel 111b and the start threshold. When the irradiation of the radiation is not detected, the reset of the plurality of pixels 111 may be performed, and the reset of the plurality of pixels 111 may include the control unit 140 having a gate module 120 and a readout module. It can be performed by controlling the (130). When the radiation is not irradiated, a dark current may be accumulated in the start detection pixel 111b, and the amount of charge read from the start detection pixel 111b may be a dark current. Since the dark current may be accumulated in all of the plurality of pixels 111 while detecting the start of irradiation of the radiation, charges for the image output are accumulated for detection of a high-quality radiation image without noise such as dark current and accurate start of irradiation. The dark current accumulated in the plurality of pixels 111 may be removed by resetting the plurality of pixels 111 before making the charge, and the amount of charge of the plurality of pixels 111 may be constant.

The irradiation start detection unit 160 may detect the irradiation start of the radiation again according to a comparison of the amount of charge newly read from the start detection pixel 111b and the start threshold, and reset the plurality of pixels 111. After performing, the amount of charge newly read from the start detection pixel 111b may be compared with the start threshold to detect the start of irradiation of the radiation again.

In the present invention, after performing a reset for a plurality of pixels 111 and detecting the start of irradiation of the radiation, the charge for the image output generated by the irradiation of the radiation is detected until the end of irradiation of the radiation is immediately detected without reset. It can accumulate and, accordingly, radiation can be effectively used without loss of radiation due to reset, etc., and there is no unnecessary radiation exposure to the examinee, thereby minimizing the dose of the examinee.

As described above, after the reset of the plurality of pixels 111 is performed so as to accumulate charge for the image output immediately after detecting the start of irradiation of the radiation, the start of irradiation of the radiation can be detected again, and the plurality of pixels After the reset for (111) is performed, the start of irradiation of the radiation may be detected again by comparing the amount of charge that is newly read in the start detection pixel 111b in which charge has accumulated for a predetermined time and the start threshold.

The radiographic method according to another embodiment of the present invention will be described in more detail with reference to FIG. 6, and overlapping with the above-described part in relation to the radiation detector according to an embodiment of the present invention will be omitted.

A radiographic method according to another embodiment of the present invention includes a plurality of pixels in which charges generated by irradiation of radiation accumulate, and the plurality of pixels are connected to a plurality of gate lines and a plurality of data lines to form a matrix. A radiation imaging method using a radiation detector including a radiation detector arranged, comprising: radiating the radiation detector to the radiation detector using a radiation generating device (S100); A step of detecting the end of irradiation of the radiation based on the amount of charge read from at least one end detection pixel determined from the plurality of pixels (S200); And scanning the plurality of pixels to read the charge for image output when the end of irradiation of the radiation is detected (S300).

First, radiation is irradiated to the radiation detector using the radiation generating apparatus (S100). The radiation detector may be irradiated with radiation using a radiation generating device, and charges generated by irradiation of radiation may be stored in a plurality of pixels of the radiation detector. When the radiation generating device and the radioactive detector are synchronous, the radiation start of the radiation generating device is known to the radiation detector, so that the radiation detector can know the start of radiation, and the radiation generating device and the radioactive detector When is asynchronous (asynchronous), the radiation detector can detect the start of irradiation of the radiation, thereby indicating the start of irradiation of the radiation.

Next, the end of irradiation of the radiation is detected based on the amount of charge read from at least one end detection pixel determined from the plurality of pixels (S200). For example, when the radiation is not irradiated, the termination reference value is determined using the amount of charge read from the termination detection pixel, and the determined termination reference value is compared with the amount of charge read (or currently read) from the termination detection pixel. The end of irradiation can be detected. At this time, when the radiation is not irradiated, a value equal to the amount of charge read from the termination detection pixel may be determined as the termination reference value, and in order to reduce the detection error, it is greater than the amount of charge read from the termination detection pixel during irradiation of the radiation. A value larger or smaller by a predetermined ratio may be determined as the termination reference value.

Then, when the irradiation of the radiation is detected, the plurality of pixels are scanned to read the image output charge (S300). When the end of irradiation of the radiation is detected, the plurality of pixels can be scanned immediately, the charge for image output can be read, and the radiographic image can be generated using the read charge for image output. Here, the charge for image output may be a charge used to generate a radiographic image, or may be a charge generated and accumulated by irradiation of the radiation until the irradiation starts and ends. The method of scanning the plurality of pixels may sequentially scan from the top left to the bottom right, and a shift register may be used for this. On the other hand, in the termination detection pixel in which the amount of charge is lost in order to detect the termination of irradiation of the radiation, charges may or may not be read while scanning the plurality of pixels.

When the end of irradiation of the radiation is not detected, the process of detecting the end of irradiation of the radiation (S200) may be performed again. When the end of irradiation of the radiation is not detected, the end of irradiation of the radiation may be detected again without reset, and the process of detecting the end of irradiation of the radiation may be repeated until the end of irradiation of the radiation is detected (S200). You can. At this time, the process of detecting the end of irradiation of the radiation (S200) may be repeated at a predetermined period, and the charges are emptied and the charges accumulated for a predetermined period (or time) can be repeatedly read at the end detection pixel. .

7 is a flowchart illustrating a process of comparing the amount of charge read and the reference end value according to another embodiment of the present invention.

Referring to FIG. 7, the process of detecting the end of irradiation of the radiation (S200) may include a process of comparing the amount of charge read from the end detection pixel with a previously stored end reference value (S210).

The amount of charge read from the termination detection pixel may be compared with a previously stored termination reference value (S210). An end reference value may be stored in advance to determine the end of irradiation of the radiation in comparison with an amount of charge read from the end detection pixel. The termination reference value may be a value that is compared with the amount of charge read from the termination detection pixel to determine the end of irradiation of the radiation, or may be the same value as the amount of charge read from the termination detection pixel when the radiation is not irradiated, In order to reduce the detection error, it may be a value that is larger or smaller by a predetermined ratio than the amount of charge read from the termination detection pixel when the radiation is not irradiated.

The irradiation end of the radiation may be determined by comparing the amount of charge read from the termination detection pixel with the termination reference value, and the current (or at the time of determination) the amount of charge read from the termination detection pixel is compared with the termination reference value. It is possible to judge the end of irradiation of the radiation.

In this case, when the amount of charge read from the termination detection pixel is equal to or less than the termination reference value, it may be determined as detection of the termination of irradiation of the radiation. Since the amount of charge accumulated in the termination detection pixel is proportional to the irradiation amount of radiation, when radiation is irradiated to the plurality of pixels of the radiation detection unit and irradiation of radiation is terminated, the amount of charge read from the termination detection pixel is reduced and the current termination The amount of charge read from the detection pixel becomes equal to or less than the termination reference value. Using this, it is possible to detect (or judge) the end of irradiation of the radiation. On the other hand, when the amount of charge read from the termination detection pixel is greater than the termination reference value, it may be determined as non-detection of radiation termination.

The radiographic imaging method according to the present invention includes a process of reading an electric charge from the termination detection pixel when irradiating the radiation and setting an termination threshold (S50); And storing the set end threshold as the end reference value (S60).

In addition, when the radiation is not irradiated, an end threshold may be set by reading charge from the end detection pixel (S50). When the radiation is not irradiated, an end threshold may be set by using the amount of charge read from the termination detection pixel, and the amount of charge read from the termination detection pixel upon irradiation of the radiation is accumulated in the termination detection pixel (or Accumulated) may be dark current, and the termination threshold may be selected as a value equal to or less than the amount of charge read from the termination detection pixel. Here, in order to reduce detection errors, the termination threshold may be selected as a value that is larger or smaller than a predetermined amount of charge read from the termination detection pixel when the radiation is not irradiated, and the predetermined ratio is a specification of the radiation detector. And radiation imaging environments. For example, when the amount of charge read from the termination detection pixel when irradiating the radiation is 0.1 pC, the termination threshold may be 0.3 pC, and in order to avoid detection errors due to vibration, the amount of charge due to vibration, etc. Even if an error occurs, the amount of charge read from the termination detection pixel should be greater than 0.3 pC when irradiating the radiation, and even if an error due to vibration occurs, the amount of charge read from the termination detection pixel during non-irradiation of the radiation It should be below 0.3 pC.

Then, the set end threshold may be stored as the end reference value (S60). The termination threshold value is stored as the termination reference value, and can be compared with the amount of charge currently read from the termination detection pixel to determine the termination of irradiation of the radiation. Through this, it is possible to detect the end of irradiation of the radiation.

At this time, the operation mode of the radiation detector may include an imaging mode for performing radiographic imaging and a standby mode before entering the imaging mode, and detecting the end of irradiation of the radiation after entering the imaging mode ( S200) may be performed. Accordingly, it may be desirable to set the end threshold value in the standby mode before entering the imaging mode, and whenever the irradiation end of the radiation that is not being irradiated is non-detected even when entering the imaging mode, The termination threshold may be reset.

The radiographic method according to the present invention may further include a step (S70) of storing a value smaller than a predetermined amount of charge read from the termination detection pixel as the termination reference value upon irradiation of the radiation.

In addition, when the radiation is irradiated, a value smaller than a predetermined amount of charge read from the termination detection pixel may be stored as the termination reference value (S70). Through this, when the radiation is irradiated, a value smaller than the amount of charge read from the termination detection pixel is used as the termination reference value, and can be compared with the amount of charge currently read from the termination detection pixel. In the case of termination, since the amount of charge read by the termination detection pixel is reduced, a value smaller than a predetermined amount of charge read by the termination detection pixel may be used as the termination reference value. At this time, when the radiation is irradiated, the amount of charge read from the termination detection pixel may be the amount of charge read from the termination detection pixel before (or at the time of the previous determination). In order to detect the end of irradiation of the radiation, the amount of charge read from the end detection pixel may be added to the end reference value or the end reference value may be updated with the amount of charge read from the end detection pixel.

For example, a value that is a predetermined percentage smaller than the amount of charge read from the termination detection pixel at a previous determination time and a value that is a certain percentage smaller than the amount of charge read from the termination detection pixel at a determination time before two cycles may be stored as the termination reference value, From the fourth determination point, a value that is a predetermined percentage smaller than the amount of charge read from the termination detection pixel at a previous determination time and a value that is a certain percentage smaller than the amount of charge read from the termination detection pixel at a previous determination time can be updated.

At the first determination time, the amount of charge currently being read from the termination detection pixel can be compared with the termination threshold, and at the second determination time, the amount of charge currently being read by the termination detection pixel is compared to the termination threshold and / or the previous determination time. It can be compared with a value smaller than a predetermined amount of charge read from the termination detection pixel, and at the third or more determination time, the amount of charge currently being read by the termination detection pixel is read from the termination detection pixel and the termination detection pixel at the previous determination time. The value may be compared with a value smaller than a predetermined amount of charge and / or a value smaller than a predetermined amount of charge read from the termination detection pixel at the time of determination two cycles earlier. At this time, the termination threshold value may be first compared with the amount of charge currently being read from the termination detection pixel, and a value smaller than the amount of charge read by the termination detection pixel at a previous determination time, the termination at a determination time two cycles ago It can be compared with the amount of charge currently read from the end detection pixel in the order of a value smaller than the amount of charge read from the detection pixel. That is, the process of detecting the end of irradiation of the radiation (S200) may be performed by first comparing the amount of charge read from the end detection pixel with the end threshold among the end reference values.

The amount of charge currently read from the end detection pixel is less than the end threshold, a value smaller than a predetermined percentage of the amount of charge read by the end detection pixel at a previous determination time, and / or read from the end detection pixel at a determination time two cycles earlier. It can be judged as detection of the end of irradiation of the radiation when the value is less than a predetermined ratio smaller than the charged amount.

The radiographic method according to the present invention may further include a process of emptying the charge accumulated in the termination detection pixel (S190).

In addition, charges accumulated in the termination detection pixel may be emptied (S190). The charge accumulated in the termination detection pixel may be emptied, and the charge accumulated from the termination detection pixel may be output before the termination threshold is set, so that the termination detection pixel is emptied, and the irradiation termination of the radiation is detected. The end detection pixel may be emptied before performing the process S200.

The process of setting the termination threshold (S50) may be performed using the amount of charge read from the termination detection pixel after the process of emptying the charge (S190). After the step of emptying the charge (S190), the termination threshold may be set by using the amount of charge read from the termination detection pixel, and after the charge accumulated in the termination detection pixel is emptied, detection of radiation termination is detected. By accumulating charges for a period performed, the termination threshold may be set by using the amount of charge read from the termination detection pixel.

In the case of detecting the end of irradiation of the radiation, since irradiation of radiation is in progress, if a reset is performed to make the charge amount of the plurality of pixels constant, the amount of charge accumulated by irradiation of radiation is removed or the Since an unnecessary amount of charge is increased for each of the plurality of pixels, it is difficult to detect the end point of accurate irradiation, and quality of the radiographic image may be deteriorated or distortion may occur.

Accordingly, after the charge accumulated in the termination detection pixel is emptied without reset, the termination threshold may be set using the amount of charge read from the termination detection pixel.

The radiographic method according to the present invention includes a process of reading a charge from the start detection pixel determined from among the plurality of pixels when irradiating the radiation and setting a start threshold (S40); And comparing the amount of charge read from the start detection pixel with the start threshold to detect the start of irradiation of the radiation (S150).

Then, when the radiation is not irradiated, a charge is read from the start detection pixel determined from among the plurality of pixels to set a start threshold (S40). When the radiation is not irradiated, the starting threshold may be set by using the amount of charge read from the starting detection pixel. When the radiation is not irradiated, the amount of charge read from the starting detection pixel is the dark current accumulated in the starting detection pixel. It may be, the start threshold may be selected as a value greater than the amount of charge read from the start detection pixel. Here, the start threshold may be selected as a value that is greater than a predetermined amount of charge read from the start detection pixel when irradiating the radiation to reduce detection errors at the start of irradiation, and the predetermined ratio of the radiation detector It can be appropriately determined according to specifications and radiographic environments. For example, when the amount of charge read from the starting detection pixel when irradiating the radiation is 0.1 pC, the starting threshold may be 0.5 pC, and an error due to vibration or the like may be used to avoid detection errors due to vibration. Even if it occurs, the amount of charge that can be read from the starting detection pixel upon irradiation of the radiation must be 0.5 pC or more, and even if an error due to vibration occurs, it can be read from the starting detection pixel during non-irradiation of the radiation. The charge amount should be less than 0.5 pC.

Thereafter, the amount of charge read from the start detection pixel is compared with the start threshold to detect the start of irradiation of the radiation (S150). The irradiation start of the radiation may be detected (or sensed) by comparing the amount of charge read from the start detection pixel with the start threshold. For example, when the radiation is not irradiated, a start threshold is set by the amount of charge read from the start detection pixel, and the set start threshold is compared with the amount of charge read (or currently read) by the start detection pixel. If the amount of charge read from the start detection pixel is greater than or equal to the start threshold, it may be determined that irradiation of the radiation is started. When the start of irradiation of the radiation is detected, a process of detecting the end of irradiation of the radiation (S200) may be performed. Meanwhile, if the amount of charge read from the start detection pixel is smaller than the start threshold, it may be determined as non-detection of the start of irradiation of the radiation.

The start threshold value may be a different charge amount value from the end threshold value. The charge for image output generated and accumulated by irradiation of the radiation is accumulated after reset so as to reduce noise such as dark current when generating a radiation image, and must be in a reset state at the time of detection of the start of irradiation. The start threshold can also be set after reset. Since the end threshold value needs only to check the amount of charge accumulated during a predetermined period (or time), it can be set after emptying the charge accumulated in the end detection pixel without a separate reset. Accordingly, the start threshold value is different from the end threshold value, and may have different charge amount values.

The radiographic imaging method according to the present invention may further include the step of resetting the plurality of pixels so that the charge amount of the plurality of pixels is constant by applying a voltage to the plurality of pixels (S140).

In addition, a voltage may be applied to the plurality of pixels to reset the plurality of pixels so that the charge amount of the plurality of pixels is constant (S140). Applying a voltage to the plurality of pixels to reset the plurality of pixels to make the charge amount of the plurality of pixels constant, and before setting the start threshold or detecting the start of irradiation of the radiation Before performing (S150), the reset of the plurality of pixels may be performed so that the charge amount of the plurality of pixels is constant, and the charge for the image output generated and accumulated by irradiation of the radiation may be accumulated. It can be made into a state. On the other hand, when entering the imaging mode of the radiation detector in the standby mode of the radiation detector, the imaging mode is performed after the charge amount of the plurality of pixels is constant through the process of resetting the plurality of pixels (S140). You can. That is, a process of detecting the start of irradiation of the radiation (S150) is performed from the time when the imaging mode is entered, and the plurality of pixels are reset before (or immediately before) the process of detecting the start of irradiation of the radiation (S150). The process (S140) may be performed.

The process of setting the start threshold (S40) may be performed using the amount of charge read from the start detection pixel after the process of resetting the plurality of pixels (S140). After the process of resetting the plurality of pixels (S140), the start threshold may be set by using the amount of charge read from the start detection pixel, and reset of the plurality of pixels may be performed so that the start detection pixel is the image. After the charge for output can be accumulated, charges are accumulated for a period at which detection of the start of irradiation of radiation is performed, and the start threshold can be set using the amount of charge read from the start detection pixel.

Meanwhile, the end detection pixel and the start detection pixel may use pixels having the same location (ie, the same pixel). At this time, the radiographic method of the present invention is the process of reading the charge from the start detection pixel (S41); And after the process of reading the charge from the start detection pixel (S41), the process of reading the charge from the end detection pixel (S51); may further include.

Charge may be read from the start detection pixel (S41). The start threshold may be set by reading electric charges from the start detection pixel.

And after the process of reading the charge from the start detection pixel (S41), the charge may be read from the end detection pixel (S51). After the charge is accumulated for a predetermined period (or time) (ie, the period at which detection of the end of irradiation of radiation is performed) in the end detection pixel emptied by the process of reading the charge from the start detection pixel (S41), the The termination threshold can be set by reading the charge from the termination detection pixel.

In this case, since the start detection pixel is read while detecting the start of irradiation of the radiation with the start detection pixel, the end detection pixel naturally occurs before setting the end threshold or detecting the end of irradiation of the radiation. It may be emptied, and the process of emptying the electric charge (S190) may not be performed. In addition, since the amount of charge is lost because the amount of charge is lost for the end of irradiation of the radiation and the start of the irradiation, the end detection pixel and the start detection pixel must be corrected. In the case of a pixel, the number of pixels to be corrected can be reduced, so that it is easy to correct the charge amount data, and the charge for image output can be read from more pixels, thereby improving the quality of the radiographic image.

When the amount of charge read from the start detection pixel is smaller than the start threshold, it may be determined as non-detection of the start of irradiation of the radiation, and the process of resetting the plurality of pixels (S140) and the start of irradiation of the radiation The detecting process (S150) may be performed again. When the amount of charge read from the start detection pixel is smaller than the start threshold, it may be determined as non-detection of the start of irradiation of the radiation, and when the start of irradiation of the radiation is not detected, the plurality of pixels are reset. The process S140 may be performed, and the process of resetting the plurality of pixels (S140) may be performed again to perform the process of detecting the irradiation start of the radiation (S150). When the radiation is not irradiated, dark current may be accumulated in the start detection pixel, and the amount of charge read from the start detection pixel may be dark current. Since dark current may be accumulated in all of the plurality of pixels while detecting the start of irradiation of the radiation, before accumulating charge for the image output for detection of a high-quality radiation image without noise such as dark current and accurate start of irradiation. The dark current accumulated in the plurality of pixels may be removed by resetting the plurality of pixels, and the amount of charge of the plurality of pixels may be constant.

The irradiation start of the radiation may be detected again according to a comparison between the amount of charge read from the start detection pixel and the start threshold, and after the process of resetting the plurality of pixels (S140), the start detection pixel is newly renewed. The start of irradiation of the radiation may be detected again by comparing the amount of charge read with the start threshold.

In the present invention, after performing the process of resetting the plurality of pixels (S140) and detecting the start of irradiation of the radiation, the image output generated by irradiation of the radiation is generated until the end of irradiation of the radiation is immediately detected without reset. It is possible to accumulate electric charges, and accordingly, radiation can be effectively used without loss of radiation due to reset and the like, and there is no unnecessary radiation exposure to the examinee, thereby minimizing the dose of the examinee.

As described above, after the reset of the plurality of pixels is performed so as to accumulate charge for the image output immediately after detecting the start of irradiation of the radiation, the start of irradiation of the radiation may be detected again, and the plurality of pixels may be detected. After the reset is performed, the start of irradiation of the radiation may be detected again by comparing the amount of charge newly read from the start detection pixel in which charge has accumulated for a predetermined time and the start threshold.

In the process of detecting the start of irradiation of the radiation (S150), a process of resetting the plurality of pixels (S140) may be performed and charges may be accumulated for a first time, and a process of detecting the end of irradiation of the radiation ( S200) may be performed by emptying the electric charge (S190) and accumulating electric charge for a second time shorter than the first time. If the process of detecting the start of irradiation of radiation (S150) is repeated, the process of resetting the plurality of pixels (S140) must also be repeated. When the first time is short, the pixel is turned on / off within a short time. Due to repeated (On / Off) and reset, frequent driving (or operation) of the pixel may cause a problem in the thin film transistor (TFT) of the pixel, and the pixel may be deteriorated or damaged. In the process of detecting the end of irradiation of the radiation (S200), the process of detecting the end of irradiation of the radiation may be repeated in a short period in order to detect the precise end time of the radiation irradiation (S200). Since it is only necessary to perform accumulation and reading, the second time can be shortened. Accordingly, the first time may be longer than the second time, and the second time may be shorter than the first time.

And the radiographic method of the present invention may further include the step of correcting the amount of charge data of the end detection pixel (and / or the start detection pixel) (S400); and the step of correcting the amount of charge data (S400) is The charge amount data of pixels adjacent to the end detection pixel (and / or the start detection pixel) (each) can be performed by interpolating (each) to the end detection pixel (and / or the start detection pixel).

The charge amount data of the end detection pixel (and / or the start detection pixel) may be corrected (S400). Since the end detection pixel and / or the start detection pixel read charge at regular intervals to detect the end of irradiation and / or the start of irradiation, the end detection pixel and / or the start detection pixel may lose charge. And, the quality of the radiographic image may be deteriorated due to the loss of the amount of charge between the end detection pixel and / or the start detection pixel. Accordingly, the charge amount data of the end detection pixel and / or the start detection pixel may be corrected to prevent (or compensate) the quality degradation of the radiographic image.

In the process of correcting the amount of charge data (S400), the amount of charge data of pixels adjacent to the end detection pixel (and / or the start detection pixel) (respectively) is assigned to the end detection pixel (and / or the start detection pixel) (respectively). ) Can be performed by interpolation. Since the end detection pixel and / or the start detection pixel occupy a very small portion of the plurality of pixels, even if the charge amount data corresponding to the end detection pixel and / or the start detection pixel is lost, there may be no problem. . However, when the end detection pixel and / or the start detection pixel are located at the center of the radiation detection unit and are an important position, the loss of charge amount data becomes a significant problem for the radiographic image, so the end detection pixel and / or the start detection pixel Charge amount data of the end detection pixel and / or the start detection pixel may be corrected by interpolating charge amount data of pixels adjacent to each pixel to the end detection pixel and / or the start detection pixel, respectively. In this case, since the median of pixels adjacent to the end detection pixel and / or the start detection pixel enters the charge amount data of the end detection pixel and / or the start detection pixel, the end detection pixel and / or the The charge amount data of the start detection pixel may be approximated to the original data of the lost detection end pixel and / or the charge amount data corresponding to the start detection pixel, thereby improving the quality of the radiographic image. Due to this, it is possible to enable accurate examination by radiographic images.

In addition, the radiographic method of the present invention is a process of obtaining a reference image when the radiation is not irradiated (S90); And subtracting the charge amount data of the reference image from the charge amount data of the plurality of pixels; (S450).

A reference image may be obtained when the radiation is not irradiated (S90), and the charge amount data of the reference image may be subtracted from the charge amount data of the plurality of pixels (S450). Through this, when the plurality of pixels are reset, it is possible to compensate for the increase or decrease of the plurality of pixels to the reference voltage V _ref .

On the other hand, in the process of detecting the end of irradiation of the radiation (S200), the charge amount value read from the termination detection pixel is compared with a preset termination threshold value, or the termination threshold value is compared to the charge amount read from the termination detection pixel. And comparing a subtracted value with a value obtained by subtracting the termination threshold value to an amount of charge previously read by the termination detection pixel (S220), and the charge amount value read from the termination detection pixel is the termination threshold. If the value is less than or equal to or less than a predetermined ratio compared to a value obtained by subtracting the termination threshold to the amount of charge read from the termination detection pixel, the value obtained by subtracting the termination threshold to the amount of charge read from the termination detection pixel It can be judged by the detection of the end of the investigation.

In the process of detecting the end of irradiation of the radiation (S200), when comparing with the end threshold, the comparison target is the amount of charge read by the end detection pixel and the value of the charge read from the end detection pixel is the When it is less than or equal to the end threshold, it can be judged as detection of the end of irradiation of the radiation.

And in the process of detecting the end of irradiation of the radiation (S200), the comparison object is different and the amount of charge read from the end detection pixel is subtracted from the end threshold, and the amount of charge previously read from the end detection pixel is the A value obtained by subtracting an end threshold value may be compared, and a value obtained by subtracting the end threshold value from the amount of charge read by the end detection pixel is a value obtained by subtracting the end threshold value from the amount of charge previously read by the end detection pixel. When the contrast is less than a predetermined ratio, it may be determined as detection of the end of irradiation of the radiation. Accordingly, when the irradiation intensity of the radiation is small and the difference between the amount of charge read from the end detection pixel and the end threshold is not large when the radiation is irradiated, the amount of charge read from the end detection pixel and the end threshold The end of irradiation of the radiation that is not detected by comparison of values can also be effectively detected.

As described above, in the present invention, by detecting the end of irradiation of radiation based on the amount of charge read from the determined end detection pixel among the plurality of pixels of the radiation detection unit, it is simple through control of the gate module and the lead-out module using a control unit without a separate complicated device. It is possible to detect the end of irradiation. In addition, by detecting the end of the irradiation of radiation and reading the charge for image output, it is possible to effectively use the radiation image without losing the irradiated radiation, and to solve the conventional problem that the quality of the radiation image is deteriorated or image defects occur. You can. In addition, the process of reading the charge for image output can be started according to the end of irradiation, so that the time required for radiography can be optimized according to the irradiation conditions of the radiation, and the battery consumption for radiography can be optimized. Accordingly, it is possible to reduce a reduction in the efficiency of equipment operation, and to suppress or prevent factors that may cause a decrease in the quality of a radiographic image due to a user's lack of operation, such as incorrectly setting a setting value related to irradiation. It may alleviate the patient's pain due to the time required. On the other hand, since the irradiation of the radiation is detected by pixels of the radiation detection unit, not as a separate device, detection errors due to vibration may be reduced.

Although the preferred embodiments of the present invention have been shown and described above, the present invention is not limited to the above-described embodiments, and the general knowledge in the field to which the present invention pertains without departing from the gist of the present invention claimed in the claims Anyone who has a will understand that various modifications and other equivalent embodiments are possible. Therefore, the technical protection scope of the present invention should be defined by the following claims.

Claims

A radiation detector having a plurality of pixels on which charges generated by irradiation of radiation accumulate, and wherein the plurality of pixels are connected to a plurality of gate lines and a plurality of data lines and arranged in a matrix form;

A gate module for selecting at least one gate line among the plurality of gate lines;

A lead-out module for selecting at least one data line among the plurality of data lines and reading charges accumulated in a pixel determined by the selected data line and the gate line selected through the gate module;

A control unit for controlling the gate module and the readout module; And

It includes; an irradiation termination detection unit for detecting the termination of irradiation of the radiation based on the amount of charge read from at least one termination detection pixel determined from the plurality of pixels;

The control unit controls the gate module and the readout module to scan the plurality of pixels and read the charge for image output when the end of irradiation of the radiation is detected.
The method according to claim 1,

The irradiation end detection unit detects the end of irradiation of the radiation again based on the amount of charge newly read from the termination detection pixel when the end of irradiation of the radiation is not detected.
The method according to claim 1,

The irradiation end detection unit,

A charge amount value input unit for receiving a charge amount value read from the termination detection pixel;

A reference value storage unit storing an end reference value for determining the end of irradiation of the radiation by comparing with the charge amount value input from the charge amount value input unit; And

And an end determination unit for determining the end of irradiation of the radiation by comparing the received amount of charge with the end reference value,

The end determination unit determines that the detection of the end of irradiation of the radiation is detected when the received charge amount value is equal to or less than the end reference value.
The method according to claim 3,

The irradiation end detection unit,

The charge amount value input unit further includes an end threshold value setting unit for setting an end threshold value using the charge amount value received when the radiation is not irradiated,

The reference value storage unit is a radiation detector that stores the termination threshold as the termination reference value.
The method according to claim 3,

The reference value storage unit is a radiation detector that stores a value smaller than a predetermined ratio of the amount of charge received upon irradiation of the radiation by the charge amount value input unit as the termination reference value.
The method according to claim 4,

The control unit controls the gate module and the readout module to empty the charge accumulated in the termination detection pixel,

The radiation detector for setting the termination threshold value by using the amount of charge received from the charge amount value input unit after the charge accumulated in the termination detection pixel is emptied.
The method according to claim 6,

It further includes an irradiation start detection unit for detecting the start of irradiation of the radiation according to a comparison of a predetermined start threshold and an amount of charge read from at least one start detection pixel determined from the plurality of pixels,

The irradiation start detection unit,

And a start threshold setting unit for setting the start threshold using the amount of charge read from the start detection pixel when the radiation is not irradiated,

The start threshold is a radiation detector value different from the end threshold.
The method according to claim 7,

The control unit controls the gate module and the lead-out module to reset the plurality of pixels, which makes the amount of charge of the plurality of pixels constant through application of a voltage,

The start threshold setting unit is a radiation detector for setting the start threshold using the amount of charge read from the start detection pixel after the reset of the plurality of pixels is performed.
The method according to claim 7,

When the start of irradiation of the radiation is not detected,

The control unit controls the gate module and the readout module to reset the plurality of pixels,

The irradiation start detection unit detects the start of irradiation of the radiation again according to a comparison of the amount of charge newly read from the start detection pixel and the start threshold.
The method according to claim 1,

The irradiation end detection unit,

A charge amount value input unit for receiving a charge amount value read from the termination detection pixel;

An end threshold value setting unit for setting an end threshold value using the amount of charge received when the radiation is not irradiated by the charge amount input unit; And

Compare the charge amount value input from the charge amount value input unit with the termination threshold, or subtract the termination threshold value from the charge amount input from the charge amount input unit and the charge amount value previously input from the charge amount input unit And an end determination unit for determining termination of irradiation of the radiation by comparing the value obtained by subtracting the end threshold,

When the charge amount value input from the charge amount value input unit is equal to or less than the termination threshold value, or the value obtained by subtracting the termination threshold value from the charge amount value input unit from the charge amount value input unit is the amount of charge previously received by the charge amount value input unit. A radiation detector judged as detection of the termination of irradiation of the radiation when the value is equal to or less than a predetermined ratio compared to a value obtained by subtracting the termination threshold.
Radiation using a radiation detector including a plurality of pixels in which charges generated by irradiation of radiation accumulate, and the plurality of pixels are connected to a plurality of gate lines and a plurality of data lines and arranged in a matrix form. In the shooting method,

Irradiating the radiation detector with the radiation using a radiation generator;

Detecting an end of irradiation of the radiation based on an amount of charge read from at least one end detection pixel determined from the plurality of pixels; And

And when the irradiation of the radiation is detected, scanning the plurality of pixels to read charges for image output.
The method according to claim 11,

If the end of irradiation of the radiation is not detected, the radiographic method of performing the process of detecting the end of irradiation of the radiation again.
The method according to claim 11,

The process of detecting the end of irradiation of the radiation,

Comparing the amount of charge read from the termination detection pixel with a pre-stored termination reference value,

When the amount of charge read from the termination detection pixel is equal to or less than the termination reference value, the radiographic method is judged as detection of the termination of irradiation of the radiation.
The method according to claim 13,

Setting an end threshold by reading charge from the end detection pixel when the radiation is not irradiated; And

And storing the set end threshold as the end reference value.
The method according to claim 13,

And storing a value smaller than a predetermined amount of charge read from the termination detection pixel as the termination reference value when the radiation is irradiated.
The method according to claim 14,

Further comprising the process of emptying the charge accumulated in the termination detection pixel;

The process of setting the termination threshold is performed by using the amount of charge read from the termination detection pixel after the process of emptying the charge.
The method according to claim 16,

Setting a start threshold by reading charge from the start detection pixel determined among the plurality of pixels when irradiating the radiation; And

Further comprising the step of detecting the start of irradiation of the radiation by comparing the amount of charge read from the start detection pixel with the start threshold value;

The starting threshold value is a radiographic method that is a different charge amount value from the ending threshold value.
The method according to claim 17,

Further comprising the step of resetting the plurality of pixels to apply a voltage to the plurality of pixels so that the charge amount of the plurality of pixels is constant.

The process of setting the starting threshold is performed by using the amount of charge read from the starting detection pixel after the process of resetting the plurality of pixels.
The method according to claim 18,

When the amount of charge read from the start detection pixel is smaller than the start threshold, it is determined as non-detection of the start of irradiation of the radiation, and the process of resetting the plurality of pixels and detecting the start of irradiation of the radiation is restarted. Radiography method performed.
The method according to claim 18,

In the process of detecting the start of irradiation of the radiation, a process of resetting the plurality of pixels is performed and charge is accumulated for a first time,

In the process of detecting the end of irradiation of the radiation, a process of emptying the charge is performed and charge is accumulated for a second time shorter than the first time, and the radiographic method is performed.
The method according to claim 11,

The process of detecting the end of irradiation of the radiation,

Compares the amount of charge read from the termination detection pixel with a preset termination threshold value, or subtracts the termination threshold from the amount of charge read from the termination detection pixel and the amount of charge previously read from the termination detection pixel. Comparing the value obtained by subtracting the termination threshold,

When the value of the amount of charge read from the end detection pixel is less than or equal to the end threshold, or when the value of the amount of charge read by the end detection pixel is subtracted from the end threshold, the amount of charge read by the end detection pixel is terminated When the threshold value is less than a predetermined ratio compared to the subtracted value, the radiographic method is judged to be the detection of the end of irradiation of the radiation.