JP6905314B2 - Radiation imaging equipment, radiography systems, radiography methods, and programs - Google Patents

Description

The present invention relates to a radiographic apparatus, a radiographic imaging system, a radiological imaging method, and a program, and more particularly to a radiological imaging apparatus, a radiographic imaging system, a radiological imaging method, and a program for testing detection pixels of automatic exposure control.

A detection device that combines a switch element such as a conversion element or a thin film transistor that converts radiation into an electric charge, a pixel array provided with wiring, and a scanning circuit or a reading circuit is widely used as a radiation two-dimensional detecting device. In recent years, as one of the multifunctional detection devices, the built-in automatic exposure control (Automatic Exposure Control: AEC) function has been studied.

This is the acquisition of various radiation information (for example, the timing of starting irradiation when radiation is emitted from a radiation source, the timing of stopping irradiation of radiation, and the instantaneous irradiation amount and integrated irradiation amount of radiation) in the detection device. Is possible. Further, this function can monitor the integrated irradiation amount, and when the integrated irradiation amount reaches an appropriate amount, the detection device can control the radiation source and end the irradiation.

Patent Document 1 discloses a technique for determining whether an error during an AEC test is affected by the sensitivity of AEC or other than that. Further, Patent Document 2 discloses a technique for appropriately selecting and determining AEC pixels after dividing AEC pixels into large blocks and small blocks.

In addition, Non-Patent Document 1 provides guidelines for quality maintenance evaluation and daily test methods in the medical imaging department.

Japanese Patent No. 4875523 Japanese Unexamined Patent Publication No. 2014-52191 "JIS Handbook 2011 Radiation (Noh)", JIS Z 4752-3-1: 2004, Japanese Standards Association

In a detection device with a built-in AEC function, radiation is detected by freely switching between valid and invalid of automatic exposure control pixels (AEC pixels). In this case, when conducting an acceptance test or daily test of the AEC function, it is necessary to perform a test involving irradiation of the minimum unit of the combination of AEC pixels, and depending on the number of AEC pixels, the test may be performed. The workload is high.

Further, when there are abnormal pixels in the AEC pixels, the workload of identifying which AEC pixel is abnormal is also high. Therefore, the present invention provides a radiography apparatus that reduces operations for detecting abnormal pixels.

The present invention is a radiography apparatus having a plurality of pixels for detecting radiation information, in which a plurality of partial regions including the plurality of pixels are set, and among the plurality of partial regions, a partial region for performing a pixel test is performed. Is provided as a region determining means for determining the test region, an activation control means for activating the pixel included in the test region, and a checking means for checking the output of the activated pixel.

INDUSTRIAL APPLICABILITY According to the present invention, when it is detected that an abnormal pixel is present in an acceptance test or a daily test, it becomes possible to confirm which pixel has an abnormality. As a result, the workload required for the test for detecting abnormal pixels can be reduced.

It is a figure which showed an example of the cross section of a detection device. It is a figure which showed an example of the equivalent circuit diagram of a detection device. It is a block diagram which shows an example of the structure of a radiography system. It is a flowchart which shows an example of the processing of the radiography apparatus which concerns on 1st Embodiment. It is a figure explaining that the target area is divided into a partial area. It is a flowchart which shows an example of the processing of the radiography apparatus which concerns on 1st Embodiment.

The outline of the present invention is shown. 1A and 1B are schematic cross-sectional views of the entire detection device. The detection device is a radiography device that tests a plurality of pixels (detection pixels) that detect radiation information in a target area.

In FIG. 1A, the radiation source 1 emits X-rays 3 toward the subject 2. The detection device 4 has a plurality of conversion elements 12 arranged in a two-dimensional matrix on the substrate 100. A scintillator 190 is arranged to face the detection device 4, and the scintillator 190 emits visible light having different intensities depending on the intensity of X-rays. By photoelectric conversion, different amounts of signals are accumulated in each conversion element depending on the light intensity at each point. An X-ray image is formed by reading this out by the method described later.

FIG. 2 is a schematic equivalent circuit diagram of the detection device 4. In the photographing area 90, the normal pixel 11 and the detection pixel 111 are arranged in a two-dimensional matrix. Hereinafter, the normal pixel and the detection pixel are collectively referred to as a pixel.

The detection device 4 has about 1000 × 1000 to 3000 × 3000 pixels, but as shown in FIG. 2A, the present embodiment has 12 × 12 pixels for simplicity. Then. The normal pixels 11 are arranged over the entire photographing region 90 in order to form a two-dimensional image used for diagnosis. As shown in FIG. 2B, the normal pixel 11 includes a conversion element 12 and a switch element 13.

The conversion element 12 is connected to the bias power supply 50 by the bias wiring 19, and a voltage for the conversion element 12 to perform the photoelectric conversion operation is applied. A plurality of signal wirings 16 are arranged in the column direction, and are commonly connected to source electrodes of switch elements having a plurality of pixels. A plurality of control wirings 15 are arranged in the row direction and are commonly connected to the gate electrodes of the switch elements of the plurality of pixels. The control wiring 15 is connected to the scanning circuit 20, and the signal wiring 16 is connected to the reading circuit 30.

When the switch element 13 becomes conductive, the signal of the pixel conversion element 12 is read by the read circuit 30 through the signal wiring 16. The detection pixel 111 is provided to acquire irradiation information (irradiation start information, irradiation end information, instantaneous irradiation amount, integrated irradiation amount, etc.). In the present embodiment, nine detection pixels 111 are included in the 12 × 12 pixels.

As shown in FIG. 2C, the detection pixel 111 includes a conversion element 121 and a switch element 131. The conversion element 121 is connected to the bias power supply 50 by the bias wiring 19, and a voltage for performing a photoelectric conversion operation is applied. The detection wiring 161 is commonly connected to the source electrode of the switch element 131 of the detection pixel 111. In the present embodiment, three detection pixels 111 are connected to one detection wiring 161.

Instead of the control wiring 15, the control wiring 411 for the detection pixel is commonly connected to the gate electrode of the switch element of the detection pixel. The scanning circuit 20, the reading circuit 30, the scanning circuit 41 for the detection pixels, and the reading circuit 40 for the detection pixels are connected to the control unit 49. The control unit 49 controls these circuits to perform various operations. By driving the control wirings 411 for the detection pixels one by one with a predetermined voltage applied to the bias wiring 19, the signal of the detection pixels 111 is read out to the detection wiring 161.

The control wirings 411 for the plurality of detection pixels connected to the detection wirings 161 are not electrically connected to each other. As a result, a plurality of detection pixels 111 connected to one detection wiring 161 can be individually driven, and detection signals can be read out in any combination of the detection pixels 111.

Further, the control unit 49 temporarily holds the irradiation information from the reading circuit 40 for the detection pixel, and performs various calculations using the irradiation information and various determinations based on the irradiation information. For example, the control unit 49 determines the timing of starting irradiation when the radiation 3 is irradiated from the radiation source 1, determines the stop timing when the irradiation of the radiation 3 is stopped, determines the instantaneous irradiation amount of the radiation, and integrates the radiation. It is possible to judge the amount.

Further, the control unit 49 is electrically connected to the radiation source 1 by wire or wirelessly, receives a start / stop signal of the radiation source 1, and controls the start or stop of radiation irradiation to the radiation source 1 as described later. You may be able to do it. Although the reading circuit 30 and the reading circuit 40 for the detection pixels are shown as separate circuits in FIG. 2, they may be integrally formed.

(First Embodiment)
The first embodiment of the present invention will be described. In the present embodiment, means for detecting abnormal pixels in the acceptance test and the daily test of the detection device 4 will be described with reference to FIGS. 3 and 4. FIG. 3 is a block diagram showing an example of the configuration of a radiography system including the radiography apparatus according to the present embodiment. FIG. 4 is a flowchart showing an example of processing of the radiography apparatus according to the present embodiment.

The description of the parts common to the above will be omitted. The radiographing apparatus has a plurality of pixels for detecting radiation information. The radiography apparatus tests a plurality of pixels (detection pixels) that detect radiation information in a target area. In the present embodiment, the pixel (detection pixel) is an automatic exposure control pixel (AEC pixel).

The radiography apparatus includes a test start instruction unit 301, an area determination unit 302, an activation control unit 303, an output unit 304, an X-ray generation unit (radiation generation unit) 305, a data acquisition unit 306, a check unit 307, and a pixel management unit. It is equipped with 308. The area determination unit 302 sets a plurality of partial areas including a plurality of pixels, and determines the partial area in which the pixel test is performed as the test area among the plurality of partial areas. The activation control unit 303 activates the pixels included in the test area. The check unit 307 checks the output of the activated pixel.

In step S401, the test start instruction unit 301 instructs the start of the test (abnormal pixel detection test) for detecting the abnormal pixel. For example, by selecting a button or the like for starting the abnormal pixel detection test, the start of the abnormal pixel detection test may be instructed, or by calibrating the detection device 4, the abnormal pixel detection test may be performed. The start may be instructed. Further, when an abnormality is detected in the image in normal shooting, the start of the abnormality pixel detection test may be instructed. When the start of the abnormal pixel detection test is instructed, the abnormal pixel detection flow is started.

In step S402, the operation circuit 41 for the detection pixels and the read circuit 40 for the detection pixels are controlled by the control unit 49 so as to enable all the AEC pixels (detection pixels). The area determination unit 302 determines all of the AEC pixels as test areas, and the activation control unit 303 activates all of the AEC pixels.

In step S403, the X-ray generator (radiation generator) 305 irradiates the activated AEC pixels with radiation. The radiation 3 emitted from the radiation source 1 is applied to the detection region 90. Since the detection pixel 111 is also irradiated with the radiation 3, the AEC pixel operates effectively. At this time, there is some abnormality in the AEC pixel, and the automatic exposure control signal may be output earlier than normally expected. If the automatic exposure control signal is output so quickly, the radiation source 1 stops the irradiation of the radiation 3.

In this case, the radiation image based on the data detected by the detection device 4 is imaged with a radiation dose smaller than expected, and there is a possibility that a desired image cannot be obtained. Therefore, it is necessary to identify the AEC pixel that outputs the automatic exposure control signal earlier than expected as an abnormal pixel and take measures.

In step S404, the image output value is checked. The check unit 307 checks the output of the AEC pixel by comparing the image pixel data with a predetermined expected value. Here, according to Non-Patent Document 1, after the photographed image is developed, the optical density of the portion designated by the densitometer must meet the expectations of the user. It doesn't become. It is confirmed whether the image data captured by the normal pixel 11 has a value (expected value) that meets the expectations of the user.

However, it can be verified by the value of the image data without developing it into a film. As stipulated in the CPI (Consistent Presentation of Image) of the technical framework of IHE (Integrating the Healthcare Enterprise), the consistency between the image data and the display is maintained.

For example, in the image resulting from automatic exposure control, the expected value should be set such that the pixel value is between 2000 and 3000 in radiography using a phantom that imitates a specified body pressure as a subject. Can be done. Therefore, if the result of determining the image output value in step S404 is as expected, it is determined that there are no abnormal pixels, and this processing flow ends. If the result of determining the image output value is different from the expected value, the processing flow of step S4 is executed.

Step S4 indicates that it is started by the area determination unit 302 and is called recursively in this processing flow. When this process is started, the process of step S405 is performed.

A partial area of the photographing area 90 targeted in step S405 is designated and processing is performed. When this flow is called for the first time, the area determination unit 302 generally covers the entire surface of the photographing area 90 as the target area.

In this step, the area determination unit 302 determines whether or not the target area can be divided into partial areas. For example, nine AEC pixels exist in the 12 pixels x 12 pixels of the shooting area 90 in FIG. 2, and the 12 pixels x 12 pixels are divided into a 6 pixel (column) x 12 pixel (row) area and a 6 pixel (column) x 12 pixel (column) x 12 pixels ( It is possible to divide it into two parts on the left and right like the area of row). When the AEC pixel is divided into two on the left and right, the AEC pixel is divided into six in the left area and three in the right area.

FIG. 5 is a diagram illustrating that the photographing area 90 is divided into partial areas. The photographing area 90 is represented by the photographing area 601 and the AEC pixel is represented by the pixel 602. The shooting area 601 of 12 pixels × 12 pixels can be divided into left and right with the center line 603 as a boundary. It is an example that the region is divided into two on the left and right, and the region can be freely divided by a known technique. In the present embodiment, as shown in FIG. 5, the photographing region 601 is divided into four partial regions 604,605,606,607.

However, when dividing, it is important to divide the area including the AEC pixel 602, and it is meaningless in this case to divide the area without the AEC pixel 602. Therefore, the area determination unit 302 determines whether or not the unit can be divided into the smallest units including the AEC pixel 602.

In some cases, each AEC pixel may not operate independently and may operate as a group. Depending on the manufacturing method of the control wiring 15 and the control unit 49, it is possible to read out for each line, but it may not be possible to read out for each pixel. In this case, the area determination unit 302 recognizes the combination of AEC pixels 602 included in each line as one group. The area determination unit 302 determines whether or not the area can be divided so as to include the group.

For example, when a known quadtree division is performed, the photographing region 601 is divided into four partial regions 604,605,606,607. The partial region 604 includes two AEC pixels 602, the partial region 605 includes one AEC pixel 602, and the partial region 606 includes four AEC pixels 602.

Further, when the partial area 606 is divided into quadtrees, it is divided into the partial areas 608, 609, 610, and 611. Each subregion 608, 609, 610, 611 includes one AEC pixel 602. If the AEC pixels can operate individually, the partial regions 608, 609, 610, and 611 are the minimum units.

If it is determined in step S410, which will be described later, that the image output value is different from the expected value, step S4 is recursively called. By repeating the division into the partial area and the check of the AEC pixel, the area determination unit 302 divides the target area or the test area into the partial area (minimum unit) including the AEC pixel that operates independently.

If it is determined in step S404 or step S410 described later that the image output value is different from the expected value and the image output value cannot be divided into partial regions (minimum units) in step S405, the process proceeds to step S407. In step S407, since the operation by the AEC pixels included in the target area is defective, the AEC pixels included in the target area are determined to be defective.

If it is determined in step S404 or step S410 described later that the image output value is different from the expected value and the image output value can be divided into partial regions in step S405, the process proceeds to step S406. In step S406, the area determination unit 302 divides the target area into partial areas including AEC pixels. In the present embodiment, since it is determined in step S405 that the AEC pixel 602 can be divided into the smallest units that can be driven, the target area is divided into partial areas.

In step S408, the area determination unit 302 determines a partial area to be tested among the plurality of partial areas as a test area. Further, the activation control unit 303 activates the AEC pixels (detection pixels) included in the test area. The activation control unit 303 controls the control unit 49 so as to enable the AEC pixels in the partial region set in step S406.

In step S409, the activated AEC pixels are irradiated with radiation 3. The irradiation of the radiation 3 is the same as in step S403, but in step S408, the irradiation is performed in a state where the AEC pixels are limited. When the output value of the AEC pixel exceeds a predetermined value, the output unit 304 outputs the automatic exposure control signal (AEC signal) of the AEC pixel by the automatic exposure control detection (AEC detection). An AEC signal is output from the output unit 304 to the X-ray generator 305.

In step S410, the check unit 307 checks the output of the activated AEC pixel. The data collection unit 306 collects image pixel data based on the AEC signal, and the check unit 307 checks the value of the image pixel data collected by the data collection unit 306. The check is the same as in step S404. The check unit 307 checks the pixel output by comparing the image pixel data with a predetermined expected value.

If the result of the image check is different from the expected value, the process returns to step S406 with the checked partial area as the target area, and the flow of step S4 is recursively executed. That is, the area determination unit 302 further divides the test area into a partial area including the AEC pixel according to the result of the check, and determines the partial area to be tested among the further divided plurality of partial areas as the test area. do. In this case, the region determination unit 302 divides the target region or the test region into partial regions including AEC pixels that operate independently.

If the result of the image check is as expected, the process proceeds to step S411 to determine the test of the next subregion. The result of the test is recorded and managed by the pixel management unit 308. The pixel management unit 308 records the check result together with the check time information.

In step S411, it is determined whether or not there is an untested region in the partial region other than the region where the flow from step S408 to step S410 is performed in the partial region divided in step S406. If there is an unimplemented partial area, the process from step S408 is carried out for that partial area.

The area determination unit 302 determines a partial area of the partial areas that has not been tested as a test area. The method for determining the next test region may be a known technique, and may be selected by using, for example, a known Morton sequence. Using the Morton order in FIG. 5, the target area of the area 606 is selected in the order of the partial areas 608, 609, 610, and 611.

By carrying out the above flow, it is possible to detect one or a plurality of abnormal pixels.

(Second embodiment)
Hereinafter, a second embodiment of the present invention will be described. The description of the parts common to the first embodiment will be omitted. An embodiment in which a daily test of AEC pixels is performed in the detection device 4 according to the first embodiment will be described with reference to the flowchart of FIG.

In step S501, an instruction to start a daily test is given. For example, the process is started by pressing the start button or the like on the operation screen of the photographing device. Further, the test start instruction unit 301 may instruct the start of the daily test (abnormal pixel detection test).

In step S502, the AEC pixel on the final test date is checked from the history information of the daily test. The daily test is managed by storing the AEC pixel and the test date in a database or the like. The pixel management unit 308 may manage the history of the check results.

For example, when a new detection device 4 is purchased, the final test dates are all the same. After that, when the test is conducted, the final test date will be updated. The history information of all the AEC pixels of the detection device 4 is held. In addition, daily tests may be performed and history management may be performed for each minimum unit of the combination of electrically driveable AEC pixels.

Step S5 represents that it is called recursively in this processing flow. When this process is started, the process of step S503 is carried out. Normally, when processing is performed first, the entire surface of the detection device 4 is set as the target area.

In step S503, it is determined whether or not there are a plurality of pixels having the oldest final test date in the target area. Normally, in the case of processing first, since the entire surface of the detection device 4 is the target area, the number of pixels having the oldest final test date among all AEC pixels can be checked.

If a plurality of oldest pixels do not exist, that is, if there is one, step S504 is executed and one AEC pixel is determined as a test pixel. When the pixel to be tested (test pixel) is determined, the processing flow in step S5 ends. If the number of AEC pixels is 0, the process ends. In this way, the area determination unit 302 determines whether or not the target area includes a predetermined number of AEC pixels.

If it is determined in step S503 that a plurality of oldest pixels exist, step S505 is executed in order to identify the pixel (or test area) to be tested from among them. The area determination unit 302 determines the test area based on the history. As will be described later, in the present embodiment, the region determination unit 302 determines the partial region having the oldest final test time of the test as the test region. Here, as the final test time, the test date may be used instead of the test time.

In step S505, it is confirmed whether or not the AEC pixel is within a predetermined range from the center of the target area. This is because when there are a plurality of AEC pixels having the same final test date, the central portion of the target region is preferentially tested. In the present embodiment, the AEC pixel in the central portion of the target region is preferentially tested, but if the AEC pixel in the central portion is not preferentially tested, this processing step may be skipped.

If the AEC pixels are within a predetermined range from the center of the target area, step S506 is executed. It is not necessary that the center of the target area and the AEC pixel are mathematically exactly the same, and an error of about several pixels from the center of the target area may be allowed.

In step S506, the processing flow of step S5 ends with the AEC pixels within a predetermined range from the center of the target area as test pixels (test areas).

In step S507, the process of dividing into partial regions is performed as in the first embodiment. In step S508, as a result of dividing into partial regions in step S507, the partial region having the oldest final test date and the largest number of AEC pixels is set as the test region. In this way, the region determination unit 302 divides the target region into the partial regions including the AEC pixels, and determines the partial region to be tested among the plurality of partial regions as the test region.

The region determination unit 302 determines the partial region having the largest number of pixels with the oldest final test time of the test as the test region. For example, as shown in FIG. 5, it is assumed that the subregions are divided into 604,605,606,607 and the final test dates of all AEC pixels are the same. In this case, since the partial region 606 includes four AEC pixels and the number of AEC pixels is the largest, the partial region 606 is determined as the test region. The flow of step S5 is recursively executed with the partial area 606 as the target area.

The test pixel is specified by recursively calling step S5 and repeating the division into subregions. For example, by recursively repeating step S503, the region determination unit 302 divides the target region or the test region into partial regions including a predetermined number of AEC pixels. Further, by recursively repeating step S505, the region determination unit 302 divides the target region or the test region until the AEC pixel exists within a predetermined range from the center of the partial region.

The test pixel is specified by recursively executing the flow of step S5. In step S509, in order to enable the specified test pixel, the scanning circuit 41 for the detection pixel and the reading circuit 40 for the detection pixel are controlled and operated by the control unit 49, and the radiation source 1 irradiates the radiation 3. do. The activation control unit 303 activates the AEC pixels (detection pixels) included in the test area. The X-ray generator (radiation generator) 305 irradiates the activated AEC pixels with radiation.

In step S510, as in the first embodiment, the validity of the AEC image is determined and recorded in the test history. The check unit 307 checks the output of the AEC pixel by comparing the image pixel data with a predetermined expected value. The pixel management unit 308 records the check result together with the check time information.

In step S511, it is determined whether or not to continue the daily test for other AEC pixels, and if the process is to be continued, step S502 is executed using the latest daily test history updated in step S510. The determination of continuation may be determined by the instruction of the user, or may be determined by whether or not a predetermined fixed number has been reached.

By carrying out the above flow, it is possible to carry out a daily test for detecting one or a plurality of abnormal pixels according to the priority for each partial region.

The present invention is not limited to these embodiments, and can be modified or modified within the scope of the claims.

The present invention supplies software (program) that realizes the functions of the above embodiments to a system or device via a network or various storage media, and a computer (CPU, MPU, etc.) of the system or device reads the program. It may be executed. The present invention can also be realized by a process in which one or more processors in a computer of a system or an apparatus reads and executes a program, and can also be realized by a circuit (for example, an ASIC) that realizes one or more functions.

1 Radioactive source 4 Detection device 11 Normal pixel 111 Detection pixel 301 Test start instruction unit 302 Area determination unit 303 Activation control unit 304 Output unit 305 X-ray generator (radiation generation unit)
306 Data collection unit 307 Check unit 308 Pixel management unit

Claims (8)

A plurality of first pixels for acquiring a radiation image, a start timing at which irradiation of radiation from a radiation source is started, a stop timing at which irradiation of the radiation is stopped, an instantaneous irradiation amount of the radiation, and the above. A radiography apparatus having a plurality of second pixels for detecting radiation information including at least one information of an integrated radiation dose.
The target region including the plurality of second pixels is divided into a plurality of partial regions, and the radiation is applied to the second pixel existing in the partial region among the plurality of the partial regions set by the division. Area determination means for determining the partial area to be irradiated and tested as the test area,
A check means for determining whether or not the second pixel included in the test area is defective by checking the pixel value in the image data captured by the first pixel included in the test area in the test.
A radiographing apparatus characterized in that it is provided with. The first aspect of the present invention is characterized in that the checking means determines whether or not the second pixel included in the test area is defective by checking whether the pixel value is within a predetermined range. Radiation imaging device. When the pixel value is not within the predetermined range in determining whether the second pixel is defective, the region determining means further divides the test region into a plurality of further subregions. The claim is characterized in that, of the plurality of the additional subregions set by the further division, the further subregion for determining whether the second pixel is defective is determined as the test region. 2. The radiography apparatus according to 2. The region determining means determines whether the second pixel is defective, and when the pixel value is within the predetermined range, the second pixel in the test among the plurality of the partial regions The radiographing apparatus according to claim 2, wherein the partial region for which the determination of whether or not the defect is defective is determined as the test region. Any of claims 1 to 4, wherein the region determining means divides the target region into the partial region including one or a plurality of the second pixels operating independently or the further partial region. The radiography apparatus according to item 1. The radiography apparatus according to any one of claims 1 to 5.
A radiation generating means for irradiating the radiographing apparatus with radiation,
A radiography system characterized by being equipped with. Apart from the plurality of first pixels for acquiring a radiation image, the timing of starting the irradiation of radiation from the radiation source, the timing of stopping the irradiation of the radiation, the instantaneous irradiation amount of the radiation, and the amount of the radiation. , A radiographing method for testing a plurality of second pixels for detecting radiation information in a target area, including at least one piece of information on the cumulative irradiation dose of the radiation.
The target area including the plurality of second pixels is divided into a plurality of partial regions, and among the plurality of the partial regions set by the division, the test of the second pixel existing in the partial region is performed. The process of determining the partial area to be implemented as the test area, and
A step of checking the pixel value in the image data captured by the first pixel included in the test region with respect to the irradiation of the radiation in the test in order to determine whether the second pixel included in the test region is defective. When,
A radiographic imaging method characterized by comprising. A program for operating a computer as each means of the radiography apparatus according to any one of claims 1 to 5.

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