JP2006271721A - Flat x-ray detector, radiodiagnosis apparatus and control method of radiodiagnosis apparatus - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a radiodiagnosis apparatus capable of continuously executing bidirectional imaging, a flat detector applied for the radiodiagnosis apparatus and a control method of the radiodiagnosis apparatus. <P>SOLUTION: This flat X-ray detector is provided with control means 5 and 17 capable of controlling ON-operation for accumulating signals in pixels mutually independently and OFF-operation of reading the signals of the pixels relative to a plurality of pixels disposed into a matrix shape and pixels of respective groups divided into a plurality of pixel groups. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to an X-ray flat panel detector, two X-ray flat panel detectors, an X-ray diagnostic apparatus capable of collecting images in different directions, and a control method for the X-ray diagnostic apparatus.

  In biplane imaging using a flat panel detector, etc., when it is attempted to continuously perform imaging in two directions, it is necessary to read out the image in the first direction and then emit X-rays in the other direction. It was. This is because the flat panel detector needs to read out the image signal line by line, so that it takes time to read out, and if any signal is incident before the image signal is read out, the signal is still read out. It is because it is added to the pixel which is not. That is, as shown in FIG. 11, in biplane imaging, before the X-ray in the first direction 52 is irradiated from the first X-ray generator 55 to the first flat detector 56 and the image is read out. Furthermore, when imaging in the second direction 51 is performed on the second flat detector 54 by X-rays from the second X-ray generator 53, scattered rays in the second direction 51 are converted into the first flat detector 56. Will be incident. For this reason, an accurate image of the subject P cannot be obtained from the first flat detector 56.

  In order to avoid such a problem, the second imaging needs to be performed after all the images of the first flat panel detector 56 are read out. Similarly, the next first imaging is performed before the first imaging. This must be done after all the images of the second flat detector 54 have been read out. Therefore, the first and second imaging are performed while being shifted by the time required for image reading by the flat detector. For this reason, at the fastest rate, it was necessary to shoot with the first and second shooting timings shifted by a half cycle.

In addition, a method of performing X-ray imaging from two different directions (biplane imaging, stereo imaging, etc.) using two X-ray flat panel detectors is performed. In this biplane imaging or the like, the following method has been proposed in order to shorten the interval between the first and second imaging without being affected by scattered radiation (see Patent Document 1). A spatially rough image is obtained after the first shot, and a fine image is obtained after the second shot. Then, the spatial distribution of scattered radiation is estimated from the rough image, and a scattered radiation image is created. Further, a desired image is reconstructed from the addition / subtraction processing of the fine image and the scattered radiation image. However, there was still a gap between the timings of the first and second shooting.
JP 2004-242873 A

  As described above, the flat detector does not have a function of blocking signals such as scattered rays, and it takes time to read out all image signals. For this reason, when biplane imaging is performed using a flat panel detector, imaging in two directions cannot be performed continuously.

  An object of the present invention is to provide an X-ray diagnostic apparatus capable of performing continuous imaging in two directions, a flat panel detector applied to the X-ray diagnostic apparatus, and a control method for the X-ray diagnostic apparatus.

  The invention according to one aspect of the present invention is an on-operation in which a signal is accumulated in a pixel independently of each other for a plurality of pixels arranged in a matrix and each group of pixels divided into a plurality of pixel groups. / The control means which can control OFF operation which reads the signal of a pixel is provided.

In addition, an X-ray diagnostic apparatus according to one aspect of the present invention includes first and second flat detectors each having a plurality of pixels arranged in a matrix, and first X-rays from a first direction. In the X-ray diagnostic apparatus capable of imaging from two different directions by detecting the X-ray from the second direction different from the first direction with the second flat detector, Means for dividing the plurality of pixels of the first flat panel detector into signal pixels and correction pixels; and X-rays from the second direction following X-ray irradiation from the first direction. Means for continuously performing exposure, and means for turning off the signal pixels of the first flat panel detector and turning on other pixels when X-rays are emitted from the first direction. When the X-ray is emitted from the second direction following the X-ray exposure from the first direction, the first and Means for turning off all the pixels of the second planar detector,
The detection value of the signal pixel of the first flat detector by the X-ray irradiation from the first and second directions is corrected by the detection value of the correction pixel of the first flat detector. And means.

  Note that the present invention is not limited to the above-described apparatus, but may be realized as an invention of a method for realizing the above-described process or an invention of a program for controlling an X-ray apparatus.

  According to the present invention, it is possible to provide an X-ray diagnostic apparatus capable of performing continuous imaging in two directions, a flat panel detector applied to the X-ray diagnostic apparatus, and a control method for the X-ray diagnostic apparatus.

  Embodiments of the present invention will be described with reference to the drawings. FIG. 1 is a block diagram showing a schematic configuration of the X-ray diagnostic apparatus according to the present embodiment. The present invention is applied to a configuration having two flat detectors (in this specification, such a configuration is referred to as a “biplane”), but the basic configuration is also applicable to a single detector. Since it is the same, FIG. 1 shows only the configuration of one flat detector.

  As shown in FIG. 1, in the X-ray diagnostic apparatus, an X-ray generation unit 12 and an X-ray detection unit 15 are supported by a holding unit 23 so as to face each other with a subject 13 interposed therebetween. A high voltage generator 10 is provided in front of the X-ray generator 12, and supplies a high voltage to the X-ray tube 11 of the X-ray generator 12. X-rays emitted from the X-ray tube 11 are shaped to have a predetermined beam width by the X-ray restrictor 22 and are emitted to the subject 13.

  X-rays that have passed through the subject 13 are detected by the flat detector 25 of the X-ray detector 15 and converted into electrical signals. The electrical signals are sequentially read under the control of the gate driver 5 and are subjected to current / voltage conversion by the charge / voltage converter 6. The electrical signal converted into the voltage signal is converted into a digital signal by the A / D converter 7 and then subjected to parallel / serial conversion by the parallel / serial converter 8 to obtain an image of the subject 13. The image signal of the subject 13 is output to an image storage circuit 16 including a large-capacity external storage device such as a memory such as a DRAM or EEPROM, an HDD, or an optical disk, for example. The charge / voltage converter 6 to the parallel / serial converter 8 constitute an image data generation unit 26.

  The image signal stored in the image storage circuit 16 is temporarily developed in the display image memory 36 of the display unit 21, then converted into an analog signal by the D / A converter 31, and converted into a video signal by the display circuit 32. And displayed on the monitor 33.

  In FIG. 1, a system control unit 17 controls the operation of each unit. Further, the system control unit 17 receives an operation of the operation unit 20 and performs control according to the operation. The operation unit 20 includes, for example, a keyboard and operation buttons. The mechanism control unit 18 performs control for moving and rotating the holding unit 23 three-dimensionally.

  FIG. 2 is a diagram showing a circuit configuration from the first and second flat detectors 25A and 25B to the first and second image storage circuits 16A and 16B. Since the first flat detector 25A and the second flat detector 25B have the same function, only one (the first flat detector 25A) will be described. The first flat detector 25A includes pixels arranged in a matrix under the photoelectric conversion film, and is connected to a signal line in the column direction and a control line in the row direction, respectively. Each pixel includes a pixel capacitor that accumulates a signal converted from an X-ray to an electric charge by a photoelectric conversion film and a switching element that controls reading of the signal. Here, when X-rays are irradiated, the photoelectric conversion film converts the X-rays into electric charges and accumulates them in the pixel capacitance of each pixel. Then, the first gate driver 5A is sequentially switched from the side closer to the first charge / voltage converter 6A, and the switching elements of the pixels are sequentially turned on. It is read sequentially every time. When reading from all the pixels is completed, reading from the first flat detector 25A is completed.

  Each pixel is composed of a pixel capacitor for accumulating signal charges and a switching element for switching between accumulation and readout of the signal charges. At present, a thin film transistor (TFT) is used as a switching element. “Off” means that the switching element is turned off and a signal can be accumulated in the pixel capacitor. “On” means that the switching element is turned on to read out the charge accumulated in the pixel capacitor.

  In addition, the flat detector includes a direct conversion type and an indirect conversion type, and this embodiment can be applied to both. The subsequent operation is the same as that described with reference to FIG.

  An operation related to the X-ray diagnostic apparatus configured as described above will be described. A feature of the present invention is that the flat detector pixels are divided into two groups of signal detection pixels and correction pixels. Hereinafter, a specific description will be given with reference to FIG. FIG. 3 is a diagram illustrating an example of an operation according to an embodiment of the present invention. 3, (a) is a diagram showing pixel allocation, and (b) is a timing chart showing pixel on / off control timing. In FIG. 3A, it is assumed that pixels are arranged at intersections of straight lines.

  As shown in FIG. 3, it is divided into two groups of signal pixels 1-1 to 1-4 and correction pixels 2-1 to 2-4. As shown in FIG. 3B, for example, the signal pixels 1-1 to 1-4 are assumed to take three types of modes of all-off, all-on, and selection-on. The operation timing of each pixel of the first flat detector and the second flat detector will be described with reference to FIG. In the present embodiment, the correction pixels of the second flat panel detector are used for signals. In the following description, X-rays in the first direction are incident on the first flat detector, and X-rays in the second direction are incident on the second flat detector. Further, X-ray exposure in the first direction is referred to as “first-direction exposure”, and X-ray exposure in the second direction is referred to as “second-direction exposure”.

  First, when performing irradiation in the first direction (time t1), only the signal pixels 1-1 to 1-4 (hereinafter referred to as “first signal pixel signals”) of the first flat panel detector. Is turned off and the other pixels are turned on. As a result, charges are accumulated in the first signal pixels 1-1 to 1-4, and other pixels, that is, correction pixels 2-1 to 2-4 (hereinafter referred to as "first pixels" of the first flat panel detector). 1 ”(referred to as“ correction pixel signal 1 ”), signal pixels 1-1 through 1-4 (hereinafter referred to as“ second signal pixel signal ”) and correction pixel 2-1. ˜2-4 (hereinafter referred to as “second correction pixel signal”), charges generated by X-rays are read without being accumulated. By this operation, the charges due to the irradiation in the first direction are accumulated in the first signal pixels 1-1 to 1-4, and the charges are not accumulated in the other pixels.

  Subsequently, when performing irradiation in the second direction (time t2), all the pixels are turned off. As a result, the scattered radiation due to the radiation in the second direction is incident on the first signal pixel and the correction pixel, so that the scattered radiation component is accumulated. In addition, X-rays by irradiation in the second direction are incident on the second signal pixel and the correction pixel.

  When the exposure in the second direction is completed (time t3), signals are sequentially read out from the pixels of the first and second flat detectors in the order of signal pixels → correction pixels. However, the accumulated charge (hereinafter referred to as “detection signal”) of the first signal pixel includes a signal component resulting from exposure in the first direction and a scattered radiation component resulting from exposure in the second direction. Here, the detection signal of the first correction pixel includes only the scattered radiation component due to the radiation in the second direction. Accordingly, by taking the difference between the detection signal of the first correction pixel and the detection signal of the first signal pixel, the influence of the radiation in the second direction can be removed. In this case, the scattered radiation component may be removed by subtracting the detection signal of the adjacent first correction pixel from the detection signal of the first signal pixel as it is, or some of the surroundings of the signal pixel may be removed. The average of the weights of the correction pixels may be taken to estimate the scattered radiation component, and the scattered radiation component may be removed. At time t4, since the reading of the detection signal of each pixel of the flat panel detector has been completed, the irradiation in the first direction can be started again.

  With the above configuration, the number of pixels of the first flat panel detector is reduced, but it is possible to continuously perform exposure in the first direction and exposure in the second direction. In the timing chart of FIG. 4, first, the detection signal from the signal pixel is read out, and then the detection signal from the correction pixel is read out. However, the order of reading is not limited to this, and FIG. As shown, the signal pixel 1-1 and the correction pixel 2-1 → the signal pixel 1-2 → the correction pixel 2-2 →... It does not matter if it is read out.

  In the above embodiment, the exposure in the first direction is always performed first, the exposure in the second direction is then performed, and then the detection signal is read from each pixel. However, in such a method, the second correction pixel can be used as a signal pixel, but the first correction pixel cannot be used as a signal pixel. Therefore, the image signal from the first flat panel detector is always Therefore, the resolution becomes one half of the image signal from the second flat panel detector. When both want to perform the same operation, it is preferable to change the order of exposure in the first direction and the second direction for each exposure. An example of this is shown in FIG. FIG. 6 is a diagram showing a timing chart when the order of exposure in the first direction and the second direction is changed for each exposure.

  First, in the first exposure (time t1), the first direction of exposure is performed, and then the second direction of exposure (time t2) is performed. Therefore, the operation is the same as the above embodiment. . In the present embodiment, in the second exposure, exposure in the second direction (time t4) is performed, and subsequently, exposure in the first direction (time t5) is performed.

  In this case, first, at the time t4, when performing irradiation in the second direction, only the second signal pixels 1-1 to 1-4 are turned off, and the other pixels are turned off. As a result, charges are accumulated in the second signal pixels 1-1 to 1-4, and other pixels, that is, the first signal pixels 1-1 to 1-4 and the first correction pixel 2- The charges generated by the X-rays are read out without being accumulated in the 1-2-4 and the second correction pixels 2-1 to 2-4. By this operation, the charges due to the radiation in the second direction are accumulated in the second signal pixels 1-1 to 1-4, and the charges are not accumulated in the other pixels.

  Subsequently, at time t5, when performing exposure in the first direction, all the pixels are turned off. As a result, scattered radiation due to irradiation in the first direction is incident on the second signal pixel and the correction pixel, and thus the scattered radiation component is accumulated. In addition, X-rays by irradiation in the first direction are incident on the first signal pixel and the correction pixel.

  Since the subsequent operation is an operation in which the first flat detector and the second flat detector are switched, the following description is omitted. As described above, in this embodiment, the order of the first direction exposure and the second direction exposure is switched for each exposure, and therefore the resolution of the first and second flat detectors ( That is, the number of pixels used as signal pixels) is changed for each exposure. Therefore, it is possible to avoid that the image in the first direction always has a low resolution.

  In the case of performing imaging independently with a single flat detector, the correction pixel may be used as the signal pixel.

  In the above embodiment, the signal pixels and the correction pixels are alternately arranged for each row. However, the present invention is not limited to this, and various arrangements can be performed. For example, an example is shown in FIG.

FIG. 7 is a diagram illustrating an arrangement example of signal pixels and correction pixels. In FIG. 7, it is assumed that four pixels of two pixels in the horizontal direction and two pixels in the vertical direction are handled as one pixel.
In FIG. 7A, similarly to the above embodiment, the signal pixels and the correction pixels are alternately arranged for each row. In FIG. 7B, the signal pixels and the correction pixels are alternately arranged in half. Specifically, for example, in the upper left four pixels, the correction pixels are arranged on the signal pixels, but in the four pixels on the right, the opposite is true, and the correction pixels are below the signal pixels. Is arranged. In FIG. 7C, the signal pixels and the correction pixels are arranged in a checkered pattern. In FIG. 7D, only one of the four pixels is used as a correction pixel, and the other pixels are used as signal pixels. In this way, the correction pixels may be arranged in any manner.

  FIG. 8 shows a connection example between each pixel and the gate line when the signal pixel and the correction pixel are arranged in a checkered pattern in the above configuration. As shown in FIG. 8, signal gate lines and correction gate lines are alternately arranged, and every other gate line is connected to pixels on both sides thereof. With such a configuration, the operation as described in the previous embodiment is possible.

As described above, only the detection signal due to the influence of scattered radiation caused by irradiation in the other direction is accumulated in the correction pixel. The signal pixel stores information in which the image signal and the influence of scattered radiation due to irradiation in the other direction are added. Therefore, in order to obtain the pixel signal, it is necessary to subtract the detection signal of the correction pixel from the detection signal of the signal pixel. In this case, for example, considering the case where one pixel is formed by four pixels, the detection signals of the signal pixels are X1 and X2, respectively, and the detection signals of the correction pixels are Y1, respectively, as shown in FIG. If Y2, the pixel signal is
Pixel signal S = X1 + X2-Y1-Y2
Given in. Thereby, detection signals of two signal pixels are obtained. Therefore, by obtaining S / 2, an average detection signal of 4 pixels can be obtained. In addition, when 2 pixels are set to 1 pixel, each detection signal S1, S2 of the signal pixel is
S1 = Y1-X1
S2 = Y2-X2
Or
S1 = Y1- (X1 + X2) / 2
S2 = Y2- (X1 + X2) / 2
You may do as follows.

For example, in the case of a checkered pattern, similarly to (a) and (b) of FIG. 7, when four pixels are treated as one pixel, the pixel signal may be obtained by averaging. On the other hand, in order to maintain the original resolution, information on pixels lacking pixel information may be interpolated by applying a large weighting coefficient to nearby objects by weighted averaging. An example is shown in FIG. In the example shown in FIG. 10, it is a figure which shows the example which interpolates y'1 pixel by Y1 to Y4 of the circumference | surroundings, Comprising: In this case, by a simple addition average,
y′1 = (Y1 + Y2 + Y3 + Y4) / 4
Thus, pixel information of y′1 is obtained.

  By performing such interpolation for each of the signal pixel and the correction pixel and then subtracting the two images, a correction image close to the original resolution can be obtained.

  In addition, in order to separate the pixels of one detector for signal use and correction use, there may be a case where there is a pixel whose signal level is unknown (a signal at the position of the correction pixel). In this case, the following two methods can be considered.

  (1) The resolution is halved, 4 pixels of 2 × 2 pixels are set as one pixel, and a large value per pixel is calculated from the signal pixels and the correction pixels in the four pixels.

  (2) On the other hand, the signal image is obtained by interpolating the signal at the position of the correction pixel from the value of the signal pixel without reducing the resolution as much as possible. At this time, on the contrary, correction images can also be obtained, and the influence of scattered radiation can be corrected between these images.

  By any one of these methods, the pixels of one detector may be separated for signal and correction.

  As described above, in the embodiment of the present invention, means for preventing the signal accumulated in the flat detector from being affected by scattered radiation and means for correcting the scattered radiation are provided. Here, in order to correct the influence of scattered radiation, all the pixels of the flat panel detector are divided into signal pixels and correction pixels so that ON / OFF control can be performed independently of each other. Therefore, in order to perform correction, the resolution is sacrificed, but there is an effect that continuous shooting in two directions is possible.

  The present invention is not limited to the above-described embodiments, and various modifications can be made without departing from the scope of the invention at the stage of implementation. In the embodiment described above, shooting in two different directions has been described, but the present invention can be similarly applied to shooting in three or more directions. Further, the above embodiments include inventions at various stages, and various inventions can be extracted by appropriately combining a plurality of disclosed constituent elements.

  In addition, for example, even if some structural requirements are deleted from all the structural requirements shown in each embodiment, the problem described in the column of the problem to be solved by the invention can be solved, and the effect described in the effect of the invention Can be obtained as an invention.

1 is a block diagram showing a schematic configuration of an X-ray diagnostic apparatus according to an embodiment. The figure which shows the circuit structure from 1st and 2nd plane detector 25A, 25B to 1st and 2nd image storage circuit 16A, 16B. The figure which shows an example of the operation | movement which concerns on one Embodiment of this invention. The figure for demonstrating the operation timing of each pixel of a 1st plane detector and a 2nd plane detector. The figure for demonstrating the operation timing of each pixel of a 1st plane detector and a 2nd plane detector. The figure which shows a timing chart when the order of the exposure of a 1st direction and a 2nd direction is changed for every exposure. The figure which shows the example of arrangement | positioning of the pixel for a signal and the pixel for a correction | amendment. The figure which shows the example of a connection of each pixel and gate line at the time of arrange | positioning the signal pixel and the correction pixel in a checkered pattern. The figure which shows the example in the case of comprising 1 pixel by 4 pixels. The figure which shows the example of interpolation of the information of the pixel which pixel information was missing. The figure for demonstrating the problem in the case of performing biplane imaging | photography.

Explanation of symbols

DESCRIPTION OF SYMBOLS 5 ... Gate driver 6 ... Charge-voltage converter 7 ... A / D converter 8 ... Parallel / serial converter 10 ... High voltage generation part 11 ... X-ray tube 12 ... X-ray generation part 13 ... Subject 15 ... X-ray Detection unit 16: Image storage circuit 17 ... System control unit 18 ... Mechanism control unit 20 ... Operation unit 21 ... Display unit 22 ... Line restrictor 23 ... Holding unit 25 ... Planar detector 26 ... Image data generation unit 31 ... D / A Converter 32 ... Display circuit 33 ... Monitor 36 ... Display image memory 51 ... Second direction 52 ... First direction 53 ... Second X-ray generator 54 ... Second flat detector 55 ... First X Line generator 56 ... first flat detector

Claims (13)

A plurality of pixels arranged in a matrix;
Control means capable of controlling an on operation for accumulating signals in the pixels and an off operation for reading out the pixel signals independently from each other for each group of pixels divided into at least two groups including a plurality of pixels. An X-ray flat panel detector characterized by that. 2. The flat panel detector according to claim 1, wherein the control means includes: a first mode that turns on all the pixels in the group; a second mode that turns off all the pixels in the group; An X-ray flat panel detector that controls a pixel in any one of the third modes in which only the pixels of a plurality of subgroups obtained by further dividing the pixel group are selectively turned on. First and second flat detectors each having a plurality of pixels arranged in a matrix are detected, X-rays from the first direction are detected by the first flat detector, and the first and second flat detectors differ from the first direction. In an X-ray diagnostic apparatus capable of imaging from two different directions by detecting X-rays from two directions with a second flat panel detector,
Means for dividing the plurality of pixels of the first flat panel detector into signal pixels and correction pixels;
Means for continuously performing X-ray irradiation from the second direction following the X-ray irradiation from the first direction;
Means for turning off the signal pixels and turning on other pixels of the first flat panel detector when emitting X-rays from a first direction;
Means for turning off all pixels of the first and second planar detectors when emitting X-rays from a second direction following exposure of X-rays from the first direction;
The detection value of the signal pixel of the first flat detector by the X-ray irradiation from the first and second directions is corrected by the detection value of the correction pixel of the first flat detector. And an X-ray diagnostic apparatus. In the X-ray diagnostic apparatus according to claim 3,
Means for dividing a plurality of pixels of the second flat panel detector into signal pixels and correction pixels;
Means for continuously performing X-ray irradiation from the first direction following X-ray irradiation from the second direction;
Means for turning off the signal pixels and turning on other pixels of the second flat panel detector when emitting X-rays from a second direction;
Means for turning off all pixels of the first and second planar detectors when emitting X-rays from a first direction following exposure of X-rays from a second direction;
The detection value of the signal pixel of the second flat panel detector by the X-ray irradiation from the first and second directions is corrected with the detection value of the correction pixel of the second flat panel detector. And an X-ray diagnostic apparatus. 5. The X-ray diagnostic apparatus according to claim 4, wherein the X-ray exposure from the second direction following the X-ray exposure from the first direction and the X-ray emission from the second direction are performed. An X-ray diagnostic apparatus characterized by alternately performing X-ray exposure from the first direction following exposure. 6. The X-ray diagnostic apparatus according to claim 3, wherein at least one of the first flat detector and the second flat detector includes a correction pixel and a signal pixel for each row. An X-ray diagnostic apparatus characterized by being arranged alternately or in a checkered pattern. 6. The X-ray diagnostic apparatus according to claim 3, wherein the number of correction pixels of at least one of the first flat detector and the second flat detector is a signal pixel. X-ray diagnostic apparatus characterized by being less than or equal to the number. 8. The X-ray diagnostic apparatus according to claim 3, wherein a scattered ray at the time of imaging in another direction is detected by the correction pixel, and the signal pixel is scattered by the detected value. An X-ray diagnostic apparatus characterized in that a line component is corrected. 9. The X-ray diagnostic apparatus according to claim 3, wherein the detection value of the signal pixel is corrected with 4 pixels of 2 pixels × 2 pixels in the plurality of pixels as one unit. 10. X-ray diagnostic apparatus characterized by the above. 9. The X-ray diagnostic apparatus according to claim 3, wherein a signal image is obtained by complementing a signal at the position of the correction pixel with a pixel value of the signal pixel. X-ray diagnostic equipment. An X-ray diagnostic apparatus comprising the X-ray flat panel detector according to claim 1. First and second flat detectors each having a plurality of pixels arranged in a matrix are detected, X-rays from the first direction are detected by the first flat detector, and the first and second flat detectors differ from the first direction. In a control method of an X-ray diagnostic apparatus capable of imaging from two different directions by detecting X-rays from two directions with a second flat panel detector,
Dividing the plurality of pixels of the first flat panel detector into signal pixels and correction pixels;
When emitting X-rays from the first direction, turn off the signal pixels of the first flat panel detector, turn on the other pixels,
Turning off all pixels of the first and second flat detectors when emitting X-rays from a second direction following X-ray exposure from the first direction;
The detection value of the signal pixel of the first flat detector by the X-ray irradiation from the first and second directions is corrected by the detection value of the correction pixel of the first flat detector. And a control method comprising: The control method according to claim 11, wherein
Dividing the plurality of pixels of the second flat panel detector into signal pixels and correction pixels;
When emitting X-rays from the second direction, turn off the signal pixels of the second flat panel detector, turn on the other pixels,
Turning off all pixels of the first and second planar detectors when emitting X-rays from a first direction following X-ray exposure from the second direction;
The detection value of the signal pixel of the second flat panel detector by the X-ray irradiation from the first and second directions is corrected with the detection value of the correction pixel of the second flat panel detector. Further comprising
X-ray exposure from the second direction following X-ray exposure from the first direction and X-ray exposure from the first direction following X-ray exposure from the second direction. A control method characterized by alternately performing line irradiation.

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