JP2002250772A - Image pickup device and image pickup method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an image pickup device and an image pickup method which can obtain an excellent image by greatly reducing the influence of a disturbance varying electromagnetic field and have high reliability. SOLUTION: An X-ray detector 52 is positioned at a position A when X-ray fluoroscopic image information by general photography is stored and at a readout position B, i.e., in an electromagnetic shield 122 when an image by general photography is read out and when a fluoroscopic image is obtained. The X-ray detector 52 is moved by using a mechanism means for moving the X-ray detector 52 according to an instruction from an image pickup controller 24 to a bed 48 for photography.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an image pickup apparatus and an image pickup method for picking up an X-ray image.

[0002]

2. Description of the Related Art In a conventional X-ray imaging apparatus, an X-ray beam is projected from an X-ray source through an object to be analyzed such as a medical patient. After the beam passes through the subject, usually an image intensifier converts the X-ray radiation into a visible light image, and a video camera creates an analog video signal from the visible image and displays it on a monitor.
Since an analog video signal is created, image processing for automatic brightness adjustment and image enhancement is performed in the analog domain.

[0003] A high-resolution solid-state X-ray detector has already been proposed, which is composed of a two-dimensional array using detection elements typified by 3000 to 4000 photodiodes in each dimension. Each element produces an electrical signal corresponding to the pixel luminance of the X-ray image projected on the detector. The signals from each detector are read out individually and digitized before being image processed, stored and displayed.

A medical X-ray image requires 4096 gradations or more. Further, since it is desired to reduce the amount of exposure by suppressing the amount of X-ray irradiation, the amount of image signals is also limited. For this reason, an extremely low noise system is required as compared with a general image sensor.

[0005]

As described above, a medical X-ray imaging apparatus requires low noise, but a CRT for computers, an uninterruptible power supply, and other devices are installed in and around the X-ray room. There are various sources of electromagnetic field generation. Therefore, in an X-ray imaging apparatus, it is desirable to avoid as much as possible that these disturbance fluctuating electromagnetic fields act as electromagnetic noise in an X-ray image.

SUMMARY OF THE INVENTION In view of the above problems, it is an object of the present invention to provide a highly reliable imaging apparatus and method capable of remarkably reducing the influence of a disturbance fluctuation electromagnetic field and obtaining a good image. And

[0007]

According to the present invention, there is provided an imaging apparatus comprising: detecting means for detecting a subject image; an electromagnetic shield; and driving means for moving at least one of the detecting means and the electromagnetic shield. The driving unit moves at least one of the detection unit and the electromagnetic shield unit such that the detection unit is covered with the electromagnetic shield unit when a signal is read from the detection unit.

[0008] An imaging apparatus according to the present invention has a detecting means for detecting a subject image, an electromagnetic shield part, and a driving means for moving at least one of the detecting means and the electromagnetic shield part. The detecting unit and the detecting unit detect that the electromagnetic wave to the detecting unit when a signal is read from the detecting unit is smaller than the electromagnetic wave to the detecting unit when the detecting unit is detecting the subject image. At least one of the electromagnetic shield portions is moved.

In one aspect of the imaging apparatus of the present invention, the driving means moves the detecting means, and the detecting means has a position at which a subject image is stored and a position at which a signal is read. The detection means is covered with the electromagnetic shield at the position where the signal is read.

In one aspect of the imaging apparatus of the present invention, the electromagnetic shield is a magnetic shield.

In one aspect of the imaging apparatus of the present invention, the electromagnetic shield has an opening for containing the detecting means and has a structure capable of covering the opening.

In one aspect of the image pickup apparatus of the present invention, the detecting means has a second electromagnetic shield part covering a part thereof.
It has a structure in which the detection unit is covered by the electromagnetic shield part and the second electromagnetic shield part.

[0013] An imaging apparatus according to the present invention comprises a detecting means for detecting an object image, an electromagnetic wave to the detecting means at the time of reading out a signal from the detecting means, and accumulating the object image of the detecting means. And an electromagnetic wave blocking unit having a function of reducing the amount of electromagnetic waves to the detecting unit when the electromagnetic wave is present.

In one aspect of the imaging apparatus of the present invention, the electromagnetic wave blocking means has an electromagnetic shield for covering the detecting means.

An image pickup apparatus according to the present invention comprises a detecting means for detecting a subject image, and a reading means for reading a signal from the detecting means.
And an electromagnetic wave blocking unit configured to cover the detection unit with an electromagnetic shield unit.

An imaging apparatus according to the present invention comprises a detecting means for detecting an image of an object, and an electromagnetic wave blocking means having a function of reducing electromagnetic waves to the detecting means. The apparatus is characterized in that at least one of the means and the electromagnetic wave blocking means is moved so that the positions thereof are overlapped.

In one aspect of the imaging apparatus of the present invention, the electromagnetic wave blocking means has an electromagnetic shield for covering the detecting means.

In one aspect of the imaging apparatus of the present invention, the electromagnetic wave blocking means has an opening for enclosing the detecting means and an electromagnetic shield having a structure capable of covering the opening.

In one aspect of the imaging apparatus of the present invention, the electromagnetic wave blocking means includes an electromagnetic shield having an opening for enclosing the detection means, and the detection means has a second part covering a part thereof. It has an electromagnetic shield part, and has a structure in which the detection means is covered with the electromagnetic shield part and the second electromagnetic shield part.

In one aspect of the imaging apparatus of the present invention, the detecting means is movable with respect to the electromagnetic wave blocking means.

In one aspect of the imaging apparatus of the present invention, the electromagnetic wave blocking means is movable with respect to the detecting means.

According to one aspect of the imaging apparatus of the present invention, the imaging apparatus selectively performs fluoroscopic imaging and general imaging using X-rays, wherein the electromagnetic wave blocking unit reads a signal of the detection unit in the general imaging. Sometimes, electromagnetic waves to the detection means are reduced.

An imaging method according to the present invention is an imaging method for detecting an object image, wherein an electromagnetic wave to the detecting means at the time of reading a signal from the detecting means for detecting the object image is detected by the detecting means. It is characterized in that the amount of electromagnetic waves is smaller than the electromagnetic wave to the detection means when the subject image is accumulated.

In one aspect of the imaging method of the present invention, the detecting means is covered with an electromagnetic shield when reading out the signal.

In one aspect of the imaging method of the present invention, the position of the detection means at the time of reading is different from the position of the detection means at the time of accumulation, and the detection means is covered with an electromagnetic shield at the time of reading. .

In one aspect of the imaging method of the present invention, the position of the electromagnetic shield at the time of reading is different from the position of the electromagnetic shield at the time of accumulation, and the detecting means is connected to the electromagnetic shield at the time of reading. Cover with.

An image pickup apparatus according to the present invention is an image pickup apparatus for picking up an image of a subject by using radiation, comprising: detecting means for detecting a radiation image of the subject; and an electromagnetic wave for reading a signal from the detecting means. And a control means for setting a radiation source that emits the electromagnetic waves to a state in which radiation of electromagnetic waves is reduced.

In one aspect of the imaging device of the present invention, the radiation source is an image display.

In one aspect of the imaging device of the present invention, the radiation source is an X-ray generator.

In one aspect of the imaging apparatus of the present invention, the state in which the radiation of the electromagnetic wave is reduced is a state in which power supply to the radiation source is stopped or reduced.

An imaging method according to the present invention is an imaging method for imaging an object using radiation. When reading a signal from a means for detecting a radiation image of the object, a radiation source for emitting electromagnetic waves is used. It is characterized in that the radiation of electromagnetic waves is reduced.

In one aspect of the imaging method of the present invention, the radiation source is an image display.

In one aspect of the imaging method of the present invention, the radiation source is an X-ray generator.

In one aspect of the imaging method of the present invention, the state in which the radiation of the electromagnetic wave is reduced is a state in which power supply to the radiation source is stopped or reduced.

[0035]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Preferred embodiments to which the present invention is applied will be described below in detail with reference to the drawings.

(First Embodiment) FIG. 1 shows a first embodiment of the present invention.
It is a block diagram of a structure of the X-ray imaging device by embodiment. 10 is an X-ray room, 12 is an X-ray control room, and 14 is a diagnostic room.

The X-ray control room 12 is provided with a system controller 20 for controlling the overall operation of the X-ray imaging apparatus according to the present embodiment. An operator interface 22 including an X-ray exposure request SW, a touch panel, a mouse, a keyboard, a joystick, a foot switch, and the like allows the operator 21 to input various commands to the system controller 20 via the interface control unit 33. used. The instruction content of the operator 21 includes, for example, shooting conditions (still image / moving image,
X-ray tube voltage, tube current, X-ray irradiation time, etc.), imaging timing, image processing conditions, subject ID, and a method for processing captured images. The imaging controller 24 controls an X-ray imaging system placed in the X-ray room 10, and the image processor 26 controls the X-ray room 10
Image processing by the X-ray imaging system. Image processor 2
The image processing in 6 includes, for example, image data correction, spatial filtering, recursive processing, gradation processing, scattered radiation correction, and dynamic range (DR) compression processing.

Reference numeral 28 denotes a large-capacity, high-speed storage device for storing basic image data processed by the image processor 26, and is composed of a hard disk array such as a RAID. Reference numeral 30 denotes a monitor display for displaying images (hereinafter, referred to as a monitor display).
Abbreviated as monitor. ), 32 are display controllers for controlling the monitor 30 to display various characters and images, 34 is a large-capacity external storage device (for example, a magneto-optical disk), and 36 is X
It is a LAN board that connects the device in the X-ray room 10 to the device in the diagnostic room 14 by connecting the device in the X-ray room 12 to the device in the diagnostic room 14.

An X-ray generator 40 for generating X-rays is placed in the X-ray room 10. The X-ray generator 40 includes an X-ray tube 42 for generating X-rays, a high-pressure source 44 controlled by the imaging controller 24 to drive the X-ray tube 42, and an X-ray generated by the X-ray tube 42. It comprises an X-ray aperture 46 for narrowing a line beam to a desired imaging area. A patient 50 as a subject lies on the imaging bed 48. The imaging bed 48 is driven according to a control signal from the imaging controller 24, and can change the direction of the patient with respect to the X-ray beam from the X-ray generator 40. An X-ray detector 52 as imaging means for detecting an X-ray beam transmitted through the subject 50 and the imaging bed 48 is arranged below the imaging bed 48.

The X-ray detector 52 comprises a laminate of a grid 54, a scintillator 56, a photodetector array 58 and an X-ray exposure monitor 60, and a driver 62 for driving the photodetector array 58. The grid 54 is provided to reduce the influence of scattered X-rays generated by transmitting X-rays through the subject 50. The grid 54 includes an X-ray low-absorbing member and a high-absorbing member, and has, for example, a stripe structure of Al and Pb. At the time of X-ray irradiation, the X-ray detector 52 is controlled by the imaging controller so that moire does not occur due to the relationship between the pixel pitch of the photodetector array 58 and the pitch of the X-ray low (high) absorbing member of the grid 54. The grid 54 is vibrated (moved) in accordance with the control signal of the driver 62 based on the setting from 24.

In the scintillator 56, the base substance of the fluorescent substance is excited by the high energy X-rays by absorbing the X-rays, and the recombination energy generates fluorescence in the visible region. That is, X-rays are converted into visible light.

[0042] The fluorescence and by maternal itself such as CaWO ₄ or CdWo _4, CsI: Ti or ZnS: is by luminescence center substance added to the inside base such as Ag.
The photodetector array 58 converts the visible light from the scintillator 56 into an electric signal.

The X-ray exposure monitor 60 is provided for monitoring the amount of X-ray transmission. As the X-ray exposure monitor 60, X-rays may be directly detected using a light receiving element made of crystalline silicon or the like, or fluorescent light from the scintillator 56 may be detected. In this embodiment, the X-ray exposure monitor 60
An amorphous silicon light-receiving element formed on the back surface of the substrate of the photodetector array 58 detects visible light (proportional to X-ray dose) transmitted through the photodetector array 58 and sends the light amount information to the imaging controller 24. introduce. The imaging controller 24 sets X
The high-voltage generation power supply 40 is controlled based on the information from the line exposure monitor 60 to adjust the X-ray dose.

The driver 62 drives the photodetector array 58 under the control of the imaging controller 24, and reads out signals from each pixel. The operation of the photodetector array 58 and the driver 62 will be described later in detail.

Reference numeral 120 denotes a fluoroscopic II (image intensifier), which is controlled by the imaging controller 24 similarly to the X-ray detector 52. After the image acquired in II is transferred to the image processor 26, it is displayed on the monitor 30 or a monitor dedicated to a fluoroscopic image (not shown). X-ray detector 52
Is located at the accumulation position A in FIG. 1 when X-ray transmission image information is stored in general imaging, and is read out position B in FIG. 1 during image reading in general imaging and during a fluoroscopic image acquisition period.
Located in. The movement of the X-ray detector 52 is performed according to an instruction from the imaging controller 24 to the imaging bed 48, and a moving operation is performed by a mechanism (not shown) for moving the X-ray detector 52. Further, the position detection sensor 121 can detect whether or not the X-ray detector 52 is located at the position B. The position detection sensor 121 may be, for example, a photo interrupter.

An image processing terminal 7 for processing images from the LAN board 36 and assisting diagnosis is provided in the diagnostic room 14.
0, a monitor 72 for displaying an image (moving image / still image) from the LAN board 36 as an image, an image printer 74, and a file server 76 for storing image data are provided.

The control signal from the system controller 20 for each device can be generated by an instruction from the operator interface 22 in the X-ray control room 12 or the image processing terminal 70 in the diagnostic room 14. .

Next, the basic operation of the system controller 20 will be described. In the system controller 20, the imaging controller 24 that controls the sequence of the X-ray imaging system controls the X-ray generator 40, the imaging bed 48, and the X-ray detector 52 based on imaging conditions based on instructions from the operator 21. By driving, an X-ray image is taken. The X-ray image signal output from the X-ray detector 52 is supplied to the image processor 26, subjected to image processing designated by the operator 21, displayed on the monitor 30, and at the same time, stored in the storage device 28 as basic image data. Is stored in The system controller 20 further performs re-image processing and image display of the result, transfer of image data to a device on a network, storage, image display, film printing, and the like, based on instructions from the operator 21.

Next, the basic operation of the system shown in FIG. 1 will be described according to the flow of signals. The high voltage source 44 of the X-ray generator 40 applies a high voltage for X-ray generation to the X-ray tube 42 according to a control signal from the imaging controller 24. As a result, the X-ray tube 42 generates an X-ray beam. The generated X-ray beam is applied to a patient 50 as a subject via an X-ray aperture 46. The X-ray stop 46 is controlled by the imaging controller 24 according to the position to be irradiated with the X-ray beam.
That is, the X-ray aperture 46 shapes the X-ray beam so as not to perform unnecessary X-ray irradiation in accordance with the change of the imaging region.

The X-ray beam output from the X-ray generator 40 is
Subject 5 lying on X-ray transparent imaging bed 48
0, and passes through the imaging bed 48 and enters the X-ray detector 52. Note that the imaging bed 48 is provided with the imaging controller 24 so that the X-ray beam is transmitted through different portions or directions of the subject.
Is controlled by

The grid 54 of the X-ray detector 52 reduces the influence of scattered X-rays caused by transmission of X-rays through the subject 50. The imaging controller 24 includes a photodetector array 58
The grid 54 is vibrated (moved) at the time of X-ray irradiation so that moire does not occur due to the above relationship between the grid 54 and the grid 54. In the scintillator 56, the base substance of the phosphor is excited by the X-rays having high energy by absorbing the X-rays, and the recombination energy generated at that time generates fluorescence in a visible region. The photodetector array 58 arranged adjacent to the scintillator 56 converts the fluorescence generated by the scintillator 56 into an electric signal. That is, the scintillator 56 converts the X-ray image into a visible light image, and the photodetector array 58 converts the visible light image into an electric signal. The X-ray exposure monitor 60 detects visible light (proportional to the X-ray dose) transmitted through the photodetector array 58, and the detection amount information is supplied to the imaging controller 24. The imaging controller 24 controls the high-voltage generating power supply 44 based on the X-ray exposure information to block or adjust the X-ray. The driver 62 controls the photodetector array 58 under the control of the imaging controller 24.
To read out pixel signals from each photodetector. Details of the photodetector array 58 and the driver 62 will be described later.

The pixel signal output from the X-ray detector 52 is applied to the image processor 26 in the X-ray control room 12.
In the X-ray room 10, since the noise accompanying the X-ray generation is large,
The signal transmission path from the line detector 52 to the image processor 26 must have high noise resistance. Specifically, a digital transmission system having an advanced error correction function or a differential driver is used. It is desirable to use twisted pairs or optical fibers with shields.

The image processor 26 switches the display format of the image signal based on a command input to the system controller 20, which will be described in detail later. As other functions, image signal correction, spatial filtering, recursive processing, and the like are performed in real time, and gradation processing, scattered radiation correction, DR compression processing, and the like can be performed. The image processed by the image processor 26 is displayed on the screen of the monitor 30. Image information (basic image) subjected to only image correction simultaneously with the real-time image processing is stored in the storage device 28. Further, based on an instruction from the operator 21, the image information stored in the storage device 28 has a predetermined standard (for example, Image).
After being reconfigured to satisfy Save & Carry (IS & C), it is stored in the external storage device 34 and the hard disk in the file server 76.

The device in the X-ray control room 12 is a LAN board 3
6 to a LAN (or WAN). Of course, a plurality of X-ray imaging systems can be connected to the LAN. The LAN board 36 has a predetermined protocol (for example, Digital Imaging and Com
munications in Medicine (D
ICOM)) to output image data. LAN
By displaying an X-ray image as a high-resolution still image or a moving image on the screen of the monitor 72 connected to the
Almost at the same time as X-ray imaging, real-time remote diagnosis by a doctor becomes possible.

FIG. 2 shows an example of an equivalent circuit of a structural unit of the photodetector array 58. One element includes a light detection unit 80 and a switching thin film transistor (TFT) 82 that controls accumulation and reading of electric charge, and is generally formed of amorphous silicon (a-Si) on a glass substrate. The light detection section 80 further includes a parallel circuit of a photodiode 80a and a capacitor 80b, and a capacitor 80c connected in series with the capacitor 80b. In addition, the charge due to the photoelectric effect is described as a constant current source 81. Capacitor 80b may be a parasitic capacitance of photodiode 80a or an additional capacitor that improves the dynamic range of photodiode 80a. Light detector 8
The 0 common bias electrode (hereinafter, referred to as a D electrode) is connected to a bias power supply 84 via a bias line Lb. An electrode on the switching TFT 82 side (hereinafter, referred to as a G electrode) of the light detection unit 80 is connected to a capacitor 86 and a charge readout preamplifier 88 via the switching TFT 82.
The input of the preamplifier 88 is also connected to a reset switch 90.
And a ground via a signal line bias power supply 91.

Here, the device operation of the light detecting section 80 will be described with reference to FIG. FIGS. 3A and 3B are energy band diagrams of the photoelectric conversion element showing the operation in the refresh and photoelectric conversion modes according to the present embodiment, and show the state of each layer in the thickness direction. Reference numeral 301 denotes a lower electrode (G electrode) made of Cr. Reference numeral 302 denotes an insulating layer made of SiN that blocks passage of both electrons and holes. The thickness of the insulating layer is set to 500 Å or more, which is a thickness such that electrons and holes cannot move due to a tunnel effect. 303 is hydrogenated amorphous silicon a-
A photoelectric conversion semiconductor layer formed of an intrinsic semiconductor i layer of Si,
Reference numeral 304 denotes an n-type a-Si injection blocking layer for preventing injection of holes into the photoelectric conversion semiconductor layer 303, and reference numeral 305 denotes an upper electrode (D electrode) formed of Al. In this embodiment, the D electrode does not completely cover the n-layer, but electrons can freely move between the D-electrode and the n-layer. Therefore, the potentials of the D-electrode and the n-layer are always the same. The description assumes that. The present photoelectric conversion element has two modes, a refresh mode and a photoelectric conversion mode, depending on how the voltages of the D electrode and the G electrode are applied.
There are different types of actions.

In FIG. 3A, a negative potential is applied to the D electrode with respect to the G electrode, and holes indicated by black circles in the i layer 303 are guided to the D electrode by an electric field. At the same time, electrons indicated by white circles are injected into the i-layer 303. At this time, some holes and electrons recombine and disappear in the n-layer 304 and the i-layer 303. If this state continues for a sufficiently long time, holes in i-layer 303 are swept out of i-layer 303.

From this state, the photoelectric conversion mode shown in FIG.
To do this, a positive potential is applied to the D electrode with respect to the G electrode. Then, the electrons in the i-layer 303 are instantaneously guided to the D electrode. However, holes are not led to the i-layer 303 because the n-layer 304 functions as an injection blocking layer. When light enters the i-layer 303 in this state, the light is absorbed and electron-hole pairs are generated. These electrons are guided to the D electrode by the electric field, and the holes move in the i-layer 303 and the i-layer 303 and the insulating layer 302.
Reaches the interface with. However, since it cannot move into the insulating layer 302, it moves to the interface of the insulating layer 302 in the i-layer 303, and a current flows from the G electrode to maintain electrical neutrality in the element. This current is proportional to the incident light because it corresponds to electron-hole pairs generated by the light. After maintaining the photoelectric conversion mode in FIG. 3B for a certain period, when the state in FIG. 3A in the refresh mode is restored, the holes remaining in the i-layer 303 are led to the D electrode as described above. At the same time, a current corresponding to this hole flows. This amount of holes corresponds to the total amount of light incident during the photoelectric conversion mode period.
At this time, a current corresponding to the amount of electrons injected into the i-layer 303 also flows, but since this amount is approximately constant, it may be detected by subtracting it. That is, the photoelectric conversion element in this embodiment can output the amount of light incident in real time, and can also output the total amount of light incident in a certain period.

However, when the period of the photoelectric conversion mode becomes long or the illuminance of incident light is high for some reason, no current may flow even though light is incident. This is because, as shown in FIG. 3C, many holes remain in the i-layer 303, and the holes recombine with the electrons in the i-layer 303 due to the holes. If the light incident state changes in this state, the current may flow in an unstable manner.
The hole 03 is swept out, and a current proportional to light flows again in the next photoelectric conversion mode.

In the above description, when the holes in the i-layer 303 are to be swept out in the refresh mode, it is ideal that all the holes are swept out. Current is obtained and there is no problem. In other words, it is sufficient that the state shown in FIG. 3C is not obtained at the next detection opportunity in the photoelectric conversion mode. The potential of the D electrode with respect to the G electrode in the refresh mode, the period of the refresh mode, and the prevention of injection of the n-layer 304 are prevented. What is necessary is just to determine the characteristics of the layer. Further, in the refresh mode, injection of electrons into the i-layer 303 is not a necessary condition, and the potential of the D electrode with respect to the G electrode is not limited to negative. This is because, when many holes remain in the i-layer 303, the electric field in the i-layer 303 is applied in a direction to guide the holes to the D-electrode even if the potential of the D-electrode with respect to the G-electrode is positive. Similarly, the characteristics of the injection blocking layer of the n-layer 304 are not a necessary condition that electrons can be injected into the i-layer 303.

Returning to FIG. 2, reading of a signal of one pixel will be described. First, the switching TFT 82 and the reset switch 90 are temporarily turned on, and the bias power 84
Is set to the potential in the refresh mode. After the capacitors 80b and 80c are reset, the bias power supply 8
4 is set to the potential in the photoelectric conversion mode, and the switching T
The FT 82 and the reset switch 90 are sequentially turned off.
Thereafter, X-rays are generated and the X-rays are emitted to the subject 50. The scintillator 54 converts the X-ray image transmitted through the subject 50 into a visible light image, and the photodiode 80a becomes conductive by the visible light image, and discharges the charge of the capacitor 80b. The switching TFT 82 is turned on to connect the capacitor 80b and the capacitor 86. This allows
The information of the capacitor 80c is also transmitted to the capacitor 86. The preamplifier 88 amplifies the voltage due to the charge stored in the capacitor 86 or the capacitor 8 indicated by a dotted line.
9, the charge-voltage conversion is performed and output to the outside.

FIG. 4 shows another example of an equivalent circuit of a constituent unit of the photodetector array 58. One element is a light detection unit 8
0 and a switching thin film transistor (TFT) 82 for controlling accumulation and reading of electric charge.
It is formed of amorphous silicon (a-Si) on a glass substrate. The light detector 80 further includes a photodiode 80
a and a capacitor 80b in parallel, and the charge due to the photoelectric effect is described as a constant current source 81. Capacitor 80b may be a parasitic capacitance of photodiode 80a or an additional capacitor that improves the dynamic range of photodiode 80a. Photodetector 80 (photodiode 80
The cathode of a) is connected to a bias power supply 85 via a bias wiring Lb which is a common electrode (D electrode). The anode of the photodetector 80 (photodiode 80a) is connected to a capacitor 86 and a charge readout preamplifier 88 from a gate electrode (G electrode) via a switching TFT.
The input of the preamplifier 88 is also connected to a reset switch 90.
And a ground via a signal line bias power supply 91.

First, the switching TFT 82 and the reset switch 90 are temporarily turned on, and the capacitor 80 is turned on.
b is reset, and the switching TFT 82 and the reset switch 90 are turned off. Thereafter, X-rays are generated and the X-rays are emitted to the subject 50. The scintillator 54 converts the X-ray image transmitted through the subject 50 into a visible light image, and the photodiode 80a becomes conductive by the visible light image,
The charge of the capacitor 80b is discharged. Switching T
The FT 82 is turned on, and the capacitors 80b and 86 are connected. As a result, the information on the discharge amount of the capacitor 80b is also transmitted to the capacitor 86. The voltage is amplified by the pre-amplifier 88 by the accumulated charge in the capacitor 86, or the charge-voltage conversion is performed by the capacitor 89 shown by a dotted line, and is output outside.

Next, the photoelectric conversion element shown in FIGS.
A description will be given of a photoelectric conversion operation in a case where the configuration is extended to a dimension. FIG. 5 is an equivalent circuit of a photodetector array 58 having a two-dimensional array of photoelectric conversion elements. Since the two-dimensional read operation is the same in the two types of equivalent circuits, FIG.
Is expressed using the equivalent circuit shown in FIG.

The photodetector array 58 has a size of 2000 × 200.
It is composed of about 0 to 4000 × 4000 pixels, and the array area is 200 mm × 200 mm to 500 mm × 500.
mm. In FIG. 3, the photodetector array 58 is 40
It consists of 96 × 4096 pixels, and the array area is 43
It is 0 mm × 430 mm. Therefore, the size of one pixel is about 105 × 105 μm. 409 placed horizontally
Six pixels form one block, and 4096 blocks are arranged in the vertical direction to form a two-dimensional configuration.

In FIG. 5, the photodetector array composed of 4096 × 4096 pixels is constituted by one substrate.
Of course, four photodetector arrays having 48 × 2048 pixels may be combined. In this case, although the trouble of assembling the four photodetector arrays is required, the yield of each photodetector array is improved, so that there is an advantage that the yield is improved as a whole.

As described with reference to FIGS. 2 and 4, one pixel is
It comprises one photodetector 80 and a switching TFT 82. Photoelectric conversion elements PD (1, 1) to (4096, 409)
6) corresponds to the light detection unit 80 and the transfer switch SW
(1,1) to (4096, 4096) indicate switching T
This corresponds to FT82. The gate electrode (G electrode) of the photoelectric conversion element PD (m, n) is connected to the corresponding switch SW (m, n).
n) to a common column signal line Lcm for that column. For example, the first row of photoelectric conversion elements PD (1, 1)
To (4096, 1) are connected to the first column signal line Lc1. All the common electrodes (D electrodes) of the photoelectric conversion elements PD (m, n) are connected to a bias power supply 8 via a bias wiring Lb.
Connect to 5.

The control terminals of the switches SW (m, n) in the same row are connected to a common row selection line Lrn. For example, the first
The row switches SW (1,1) to (1,4096) are connected to the row selection line Lr1. Row selection lines Lr1-4096
Is connected to the imaging controller 24 via the line selector 92. A line selector 92 that decodes the control signal from the imaging controller 24 and determines which line of the signal charge of the photoelectric conversion element to read out;
409 which is opened and closed according to the output of the address decoder 94
It is composed of six switch elements SW1 to 4096.
With this configuration, the photoelectric conversion element PD (m, n) connected to the switch SW (m, n) connected to an arbitrary line Lrn
The signal charge of n) can be read. As the simplest configuration, the line selector 92 may be configured simply by a shift register used for a liquid crystal display or the like.

The column signal lines Lc1 to 4096 are connected to a signal readout circuit 100 controlled by the imaging controller 24. In the signal reading circuit 100, reference numerals 102-1 to 4096 denote switches for resetting, and the column signal lines Lc1 to Lc1
4096 is reset to the reset reference potential 101. 1
06-1 to 4096 are column signal lines Lc1 to Lc40, respectively.
Preamplifier for amplifying the signal potential from 96, 108-1
-4096 are preamplifiers 106-1 to 4096, respectively.
Sample and hold (S /
H) circuit, 110 is an analog multiplexer that multiplexes the outputs of 108-1 to 4096 on the time axis, and 112 is an A / D converter that digitizes the analog output of the multiplexer 110. The output of the A / D converter 112 is supplied to the image processor 26.

In the photodetector array shown in FIG.
× 4096 pixels are divided into 4096 columns by column signal lines Lc1 to 4096, and signal charges of 4096 pixels per row are simultaneously read out, and each column signal line Lc1 to 409 is read.
6. Preamplifiers 106-1 to 4096 and S / H circuit 1
08-1 to 4096 to the analog multiplexer 110, where the signals are time-division multiplexed, and A /
The signal is converted into a digital signal by the D converter 112.

Although FIG. 3 shows that the signal readout circuit 100 includes only one A / D converter 112, the signal readout circuit 100 actually performs A / D conversion simultaneously in 4 to 32 systems. This is because it is necessary to shorten the image signal reading time without unnecessarily increasing the analog signal band and the A / D conversion rate. The accumulation time of the signal charge and the A / D conversion time are closely related.
If the A / D conversion is performed at a high speed, the bandwidth of the analog circuit is widened and it is difficult to achieve a desired S / N. Short reading times are required. The output of the multiplexer 110 is A / D-converted by many A / D converters.
The conversion may be performed, but as the number of A / D converters increases, the cost increases accordingly. Therefore, an appropriate number of A / D converters are used in consideration of the above points.

X-ray irradiation time is about 10 to 500 ms
Because of ec, it is appropriate to set the capture time or the charge storage time of the entire screen to the order of 100 msec or slightly shorter. For example, in order to sequentially drive all the pixels and take in an image in 100 msec, the analog signal band is set to about 50 MHz, and A / D conversion is performed at a sampling rate of 10 MHz. Vessel is required. In this embodiment, A / D conversion is performed simultaneously in 16 systems. The outputs of the 16 A / D converters are input to corresponding 16 memories (not shown) such as FIFOs. By selecting and switching the memory, image data corresponding to one continuous scanning line is transferred to the image processor 26.

FIG. 6 is a schematic timing chart of sensor reading. Two-dimensional driving in a case where a still image is captured by one X-ray irradiation will be described together with FIG. 601
Is an X-ray irradiation request control signal, 602 is an X-ray irradiation state, 603 is a current of the current source 81 in the sensor, 604 is a control state of the row selection line Lrn, and 605 is an analog signal to the AD converter 112. Each input is represented schematically.

In the equivalent circuit sensor shown in FIG. 2, first, the driver 62 sets the bias wiring to the bias value Vr in the refresh mode, and sets all the column signal wirings Lc1 to 4096 to the initial bias value of the column signal wiring Lc. Connected to the reset reference potential 101 and all the row selection lines Lr1
A positive voltage Vgh is applied to .about.4096. Then, SW (1,
1)-(4096,4096) are turned on, and G of all photoelectric conversion elements
The electrode is refreshed to Vbt and the D electrode is refreshed to Vr.
Thereafter, the driver 62 sets the bias line Lb to the bias value Vs at the time of photoelectric conversion, releases all the column signal lines Lc1 to 4096 from the reset reference potential 101, and switches SW (1,1) to SW (1,1).
In order to turn off (4096,4096), all the row selection lines L
A voltage Vgl is applied to r1 to 4096. Thereby, the mode shifts to the photoelectric conversion mode.

Since the operation is common to the respective equivalent circuit sensors shown in FIGS. 2 and 4, description will be made at the same time. All the column signal lines Lc are connected to the reset reference potential 101 with the bias lines kept at the bias value Vs at the time of photoelectric conversion, and the column signal lines are reset. Thereafter, a positive voltage Vgh is applied to the row selection wiring Lr1, and SW (1,1) to (1,409)
6) is turned ON, and the G electrode of the photoelectric conversion element in the first row is set to Vbt.
Reset to. Next, the row selection line Lr1 is set to the positive voltage Vgl.
And SW (1,1) to (1,4096) are turned off. Row selection is sequentially repeated to reset all the pixels, and the preparation for photographing is completed. The above operation is the same as the operation of reading out the signal charge, and there is no choice as to whether or not to take in the signal charge. Therefore, this reset operation is hereinafter referred to as “idle reading”. During this idle reading operation, it is possible to set all the row selection lines Lr to Vgh at the same time, but in this case, when the read preparation is completed, the signal line potential greatly deviates from the reset voltage Vbt, and the high S / N It is difficult to get a signal. In the above example, the row selection line Lr was reset from 1 to 4096, but the driver 6 based on the setting of the imaging controller 24 was reset.
The reset can be performed in an arbitrary order by the control of (2). Then, the idle reading operation is repeated to wait for an X-ray exposure request.

When an irradiation request is issued, a blank reading operation is performed again to prepare for X-ray irradiation in preparation for image acquisition. When preparation for image acquisition is completed, X-rays are emitted in accordance with an instruction from the imaging controller 24.

After the X-ray exposure, the signal charges of the photoelectric conversion element 80 are read. First, Vgh is applied to the row selection wiring Lr for a row (for example, Lr1) of the photoelectric conversion element array,
The stored charge signal is output to the signal lines Lc1 to 4096. Signals for 4096 pixels are simultaneously read out from the column signal lines Lc1 to 4096 one by one.

Next, different row selection lines Lr (for example, Lr
Vgh is applied to 2), and the accumulated charge signal is applied to the signal line Lc1.
Output to ~ 4096. Signals for 4096 pixels are simultaneously read from the column signal lines Lc1 to 4096 one by one. 4096
All image information is read out by sequentially repeating the above-mentioned row selection wiring.

During the above operation, the charge accumulation time of each sensor is set at the time when the reset operation is completed, that is, after turning off the TFT 82 at the time of the idle reading, and the next time the electric charge is read out.
This is until the FT82 turns on. Therefore, the accumulation time / time differs for each line selection line.

After reading the X-ray image, a correction image is obtained. This is for use in correcting X-ray images,
This is correction data necessary for obtaining a high-quality image.
The basic image acquisition method is the same except that X-rays are not exposed. The charge accumulation time is the same when reading an X-ray image and when reading a corrected image.

FIG. 7 is a timing chart including the general imaging operation of the X-ray detector 52. The operation of the X-ray detector 52 according to the present embodiment will be described mainly with reference to FIG. Reference numeral 700 denotes an imaging request signal to the operator interface 22, which represents a request for fluoroscopy and simple imaging.

Reference numeral 701 denotes an X-ray generator ready signal; 702, an actual X-ray irradiation state; 703, an imaging request signal from the imaging controller 24 to the driver 62 based on an instruction from the operator 21;
4 is an imaging ready signal of the X-ray detector 52, 705 is a driving signal of the grid 54, 706 is a power control signal in the X-ray detector 52, and 707 is a driving state of the X-ray detector (particularly from the photodetector array 58). Charge readout operation). Reference numeral 708 conceptually represents the transfer state of image data, and the state of image processing and display. Further, reference numeral 709 denotes an X-ray output state for X-ray or the like, 710 denotes the concept of the moving speed of the X-ray detector 52, and 711 denotes the position of the X-ray detector in FIG.

While there is no request from the operator 21, the X-ray detector 52 stands by at the position B of the imaging bed 48 with the power control turned off as indicated by reference numeral 706. Specifically, in FIG. 5, the potentials of the row selection line Lr, the column signal line Lc, and the bias wiring Lb are maintained at the same potential (particularly, the signal GND level) by a switch (not shown), and no bias is applied to the photodetector array 58. Further, the power supply including the signal readout circuit 100, the line selector 92, and the bias power supply 84 or 85 may be cut off to keep the potentials of the row selection line Lr, column signal line Lc, and bias wiring Lb at the GND potential. .

When there is a fluoroscopic request (700: fluoroscopic request) from the operator 21, the imaging controller 24 starts fluoroscopic imaging (709), and simultaneously shifts the X-ray detector 52 to the detector preparation state. Give instructions. Upon receiving the instruction, the driver 62 applies a bias to the photodetector array 58,
Repeat (refresh and) blank reading Fi.

In the detector preparation state, in the photoelectric conversion mode, to prevent the dark current from gradually accumulating in the photodetecting section 80 after the idle reading and the capacitor 80b (c) is kept in a saturated state, (refreshing). R and / or blank reading Fi are repeated at predetermined intervals. Driving performed during a period in which there is an imaging preparation request from the operator 21 but no actual X-ray irradiation request has been issued, that is, a blank reading Fi performed in the detector preparation state.
Is repeated at a predetermined time interval T1, hereinafter referred to as "idling drive", and the period of the detector ready state in which idling driving is performed is referred to as "idling drive period". Since how long the idling drive period lasts is undefined in practical use, the photodetector array 58 (particularly, T
In order to minimize the read operation that places a load on the FT 82), T1 is set to be longer than that in the normal photographing operation, and the idle read-only drive Fi in which the ON time of the TFT 82 is shorter than the normal read drive Fr is performed. In the case of a sensor that requires a refresh R operation, the refresh R operation is performed once for several times of the idle reading Fi.

When the operator 21 determines an imaging target and makes a general imaging preparation request (700: 1st switch), the X-ray generator 40 starts preparations for X-ray generation for general imaging, and prepares after a predetermined time. Complete.

Next, acquisition of an X-ray image centered on the X-ray detector 52 will be described. The driving of the X-ray detector 52 at the time of acquiring an X-ray image mainly includes two image acquisitions. As indicated by reference numeral 707, one is an X-ray image acquisition drive, and the other is a correction dark image acquisition drive. Each drive is almost the same, and the main difference is whether or not there is an operation for performing X-ray irradiation. Further, each drive is composed of three parts: an imaging preparation sequence, charge accumulation (exposure window), and image reading.

Hereinafter, X-ray image acquisition will be described step by step. In response to an imaging request instruction (700: 2nd SW) from the operator 21 to the operator interface 22, the imaging controller 24 controls the imaging operation while synchronizing the X-ray generator 40 and the X-ray detector 52 to perform fluoroscopic imaging. Cancel (70
9) The X-ray detector 52 is moved from position B to position A (710 and 711). Since the time T3 until the preparation of the X-ray detector 52 for imaging is known in advance, the movement of the X-ray detector 52 to the general imaging position A is completed in a time corresponding thereto. However, in 707, Fp immediately before the completion of the shooting preparation
If vibration occurs at the time of the f-frame, the noise tends to ride on the image.
Control is performed so as to move at a constant speed so that no acceleration is generated until then.

The imaging request signal is asserted to the X-ray detector 52 at the timing indicated by the X-ray irradiation request signal 703 in accordance with the imaging request instruction (700: 2nd SW). The driver performs a predetermined imaging preparation sequence drive in response to the imaging request signal as shown in an imaging driving state 707. In particular,
When the refresh is necessary, the refresh is performed, and the dedicated idle reading Fp for the imaging sequence is performed a predetermined number of times and the dedicated idle reading Fpf for the charge accumulation state is performed, and the state is shifted to the charge accumulation state (imaging window: T4). At this time, the number of times of the idle reading Fp for the imaging sequence and the time interval T2
Is performed based on a value set in advance prior to an imaging request from the imaging controller 24. In this case, the optimum drive is automatically selected and switched depending on whether the operability or the image quality is important according to the request of the operator 21 or the imaging part. In the period (T3) from the exposure request to the completion of the imaging preparation, it is actually required that the required time is short. Therefore, the special readout Fp for the imaging preparation sequence is performed. Furthermore, if an exposure request occurs from any state of idling drive,
By entering the immediate imaging preparation sequence drive, the period (T3) from the exposure request to the completion of imaging preparation is shortened, and the operability is improved.

The driver 62 starts to move the grid 54 in synchronization with the preparation of the detector array 58 for imaging. This is because the grid is imaged in an optimal moving state in synchronization with the actual X-ray irradiation 702. Also in this case, the driver 62 operates at the optimum grid movement start timing and the optimum grid movement speed set by the imaging controller.

When the X-ray detector 52 is ready for imaging, the driver 62 returns an X-ray detector ready signal 704 to the imaging controller 24, and the imaging controller 24 makes a transition based on this signal. The X-ray generation request signal 702 is
Assert to 0. The X-ray generator 40 generates X-rays while the X-ray generation request signal 702 is being given. Predetermined X
When the dose is generated, the imaging controller 24 outputs the X-ray generation request signal 7
02 is negated and the X-ray imaging request signal 703 is negated. The driver 62 immediately stops the grid 54 based on this timing.

At the same time, the X-ray detector 52 is moved to the position B. In this case, control is performed so as to move to the position B in as short a time as possible. Then, the X-ray detector 52
When the position detection sensor 121 detects that has moved to the predetermined position of the position B, the X-ray detector 52 is notified of the image acquisition timing.

Then, the operation of the signal readout circuit 100 which has been in the standby state is started. Signal readout circuit 1
After a predetermined wait time for stabilizing 00, image data is read from the X-ray detector array 58 based on the driver 62 and a raw image is transferred to the image processor 26. When the transfer is completed, the driver 62 changes the read circuit 100 to the standby state again.

Subsequently, the X-ray detector 52 acquires a correction image. That is, the imaging sequence for the previous imaging is repeated to obtain a dark image without X-ray irradiation, and the image processor 26
To the correction dark image. At this time, the imaging sequence may be slightly different such as the X-ray exposure time for each imaging, but by reproducing the same imaging sequence including that, and acquiring a dark image, a higher quality image can be obtained. can get. However, the operation of the grid 54 is not limited to this, and when the dark image is obtained, the grid 54 is kept stationary to suppress the influence of vibration. After the dark image is obtained, the grid 54 is initialized at a predetermined timing that does not affect the image quality.

When the X-ray detector 52 moves to the position B, the fluoroscopic imaging can be resumed, and the fluoroscopic image can be displayed again from this time.

In the X-ray imaging apparatus, an electromagnetic field source such as an image display 51 or an X-ray generator 40 exists near the detector. These devices are sources of electromagnetic noise that give artifacts to X-ray images. Especially CR
An image display such as T generates a periodic electromagnetic wave of 50 to 200 kHz, which may cause a noticeable artifact on the image.

In the present embodiment, the devices that can be the source of these electromagnetic noises are shifted to a state in which the emission of electromagnetic waves is reduced while the system control signal 712 is asserted (while LOW). Specifically, the power supply to the device is turned off or reduced (transition to a standby mode).

When the reading of the image signal is completed and the system control signal 712 is negated, the above-mentioned device returns to the normal operation state.

An X-ray image is easily affected by electromagnetic field noise when an image signal is read. At the time of reading the image signal, the sample and hold are performed in the sub-scanning cycle, and noise superimposed on the signal line at the timing of the hold easily affects the image as an artifact.

In this embodiment, at the time of image signal reading, radiation of electromagnetic field noise is reduced, and a good X-ray image can be obtained.

FIG. 8 shows the image processor 26, which shows the flow of image data. 801 is a multiplexer for selecting a data path, 802 and 803 are frame memories for X-ray images and dark images, 804 is an offset correction circuit, 805 is a frame memory for gain correction data, 806 is a circuit for gain correction, and 807 is a defect. A correction circuit 808 represents each of the other image processing circuits.

In FIG. 7, the X-ray image acquired by the X-ray image acquisition frame Frxo frame is stored in the X-ray image frame memory 802 via the multiplexer 801.
Subsequently, the corrected image obtained in the corrected image obtaining frame Frno frame is similarly stored in the dark image frame memory 803 via the multiplexer 801. After the storage of the dark image is completed, offset correction (for example, Frxo-Frno) is performed by the offset correction circuit 804, and the gain correction circuit Fg is obtained using the gain correction data Fg acquired in advance and stored in the gain correction frame memory. 806 is a gain correction (for example, (Frxo-Frn
o) / Fg). The data continuously transferred to the defect correction circuit 807 interpolates the image continuously so as not to cause a sense of incongruity at a dead pixel or at a joint portion of the X-ray detector 52 composed of a plurality of panels. The sensor-dependent correction processing derived from 52 is completed. Further, the other image processing circuit 808 performs general image processing, for example, processing such as gradation processing, frequency processing, and enhancement processing.
Thereafter, the processed data is transferred to the display controller 32, and the captured image is displayed on the monitor 30.

In the present embodiment, the system control signal is also asserted during the period between the readout of the image signal of the X-ray image and the readout of the image signal of the correction dark image. At least, it is only necessary to be asserted at the time of reading each image signal.

In this embodiment, the image display and the X-ray generator are shifted to a state in which radiation noise is reduced at the time of reading image signals. However, the same applies to various motors and cooling fans. is there.

Further, in this embodiment, the equipment included in the X-ray imaging apparatus is shifted to a state in which radiation noise is reduced. However, other equipment that is not included in the X-ray imaging apparatus but can be a noise source, for example, an air conditioner The same control may be performed on a machine or the like.

As described above, according to the present embodiment, it is possible to realize a highly reliable X-ray imaging apparatus capable of remarkably reducing the influence of a disturbance fluctuation electromagnetic field and obtaining an excellent image. Can be.

-Modifications- Various modifications of the X-ray imaging apparatus according to the present embodiment will be described below.

(Modification 1) FIG. 9 is a configuration block diagram of an X-ray imaging apparatus according to Modification 1. The X-ray imaging apparatus of this modified example has substantially the same configuration as the X-ray imaging apparatus shown in FIG. 1, but differs in that an electromagnetic wave blocking unit is provided.

The electromagnetic wave blocking means is configured as an electromagnetic shield 122. Electromagnetic shield is mainly 10kHz
Low frequency magnetic shield below 1kHz and 1kHz-1
Refers to the shield against the near field from 0 kHz to 40 GHz. Materials for electromagnetic shielding include iron foil, permalloy,
Alternatively, a material using an amorphous material for the soft magnetic material may be used. The X-ray detector 52 is positioned at the readout position B in FIG.
, The position of the X-ray detector 52 and the position of the electromagnetic shield 122 overlap with each other, except for a portion that becomes a passage when the X-ray detector 52 moves, and Are surrounded by an electromagnetic shield 122.

Here, the X-ray detector 52 and the electromagnetic shield 1
22 (electromagnetic wave blocking means) may be configured such that one moves relatively to the other, instead of the structure in which the X-ray detector 52 moves relative to the electromagnetic shield 122 fixed as described above. In addition, a configuration in which the electromagnetic shield 122 moves with respect to the fixed X-ray detector 52 is also suitable.

The storage of the X-ray transmission image information is performed at the storage position A which is not surrounded by the electromagnetic shield. However, the photographic image is easily affected by the electromagnetic field noise when reading the image signal. In the embodiment, the image signal readout is performed at the readout position B surrounded by the electromagnetic shield, so that it is possible to reduce the influence of disturbance electromagnetic field noise and obtain a good X-ray image.

As described above, according to the first modification,
It is possible to realize a highly reliable X-ray imaging apparatus capable of remarkably reducing the influence of a disturbance fluctuation electromagnetic field and obtaining an extremely good image.

(Modification 2) FIGS. 10 and 11 are perspective views showing a state near an X-ray detector and an electromagnetic shield according to Modification 2 of the present invention. In the first modification, at the readout position B surrounded by the electromagnetic shield, the electromagnetic shield is not applied to a portion that becomes a path when the X-ray detector 52 moves, but as shown in FIG. Line detector 52
When the position detection sensor 121 detects that the X-ray detector 52 is located at the position B and reads out a signal, the electromagnetic shield 130 is also covered by a mechanism (not shown) on a portion that passes when the X-ray detector 52 moves. Thus, the X-ray detector 5
The signal readout may be performed in a state where the entire surface of the device 2 is covered with the electromagnetic shield. In this case, the disturbance electromagnetic field is more effectively cut off.

Further, as shown in FIG. 11, an electromagnetic shield 131 is previously applied to one surface of the X-ray detector 52.
When the X-ray detector 52 is located at the position B, the structure may be such that the entire surface of the X-ray detector 52 is covered with the electromagnetic shield. Also in this case, the disturbance electromagnetic field is more effectively cut off.

In the present embodiment and its modifications, a system in which fluoroscopic imaging and general imaging are mainly combined has been described. However, even in a system in which only general imaging is performed, the same structure is adopted by adopting a similar structure. It is possible to obtain the effect of

In the case of only general radiography, the electromagnetic shield may be moved instead of moving the X-ray detector.

In addition to the configuration described above, the influence of electromagnetic waves on the X-ray detector when a signal is read from the X-ray detector can be measured by using the method of detecting a subject image of the X-ray detector. X
Any configuration having a function of reducing the influence of the electromagnetic wave on the line detector may be used.

[0118]

According to the present invention, it is possible to provide a highly reliable imaging apparatus and an imaging method capable of remarkably reducing the influence of a disturbance fluctuating electromagnetic field and obtaining an excellent image.

[Brief description of the drawings]

FIG. 1 is a configuration block diagram illustrating an X-ray imaging apparatus according to an embodiment.

FIG. 2 is an equivalent circuit diagram illustrating an example of a configuration unit of a photodetector array.

FIG. 3 is a schematic diagram for explaining a device operation of a light detection unit.

FIG. 4 is an equivalent circuit diagram showing another example of the constituent units of the photodetector array.

FIG. 5 is an equivalent circuit diagram of a photodetector array including a two-dimensional array of photoelectric conversion elements.

FIG. 6 is a timing chart showing an outline of sensor reading.

FIG. 7 is a timing chart including a general imaging operation of the X-ray detector.

FIG. 8 is a processing flow block diagram of an acquired image by an image processor.

FIG. 9 is a block diagram illustrating a configuration of an X-ray imaging apparatus according to a first modification of the embodiment.

FIG. 10 is a perspective view showing a state in the vicinity of an X-ray detector and an electromagnetic shield according to a second modification of the embodiment.

FIG. 11 is a perspective view showing a state near an X-ray detector and an electromagnetic shield according to a second modification of the embodiment.

[Explanation of symbols]

 10: X-ray room 12: X-ray control room 14: Diagnosis room 20: System controller 21: Operator 24: Imaging controller 26: Image processor 30: Monitor 40: X-ray generator 48: Imaging bed 50: Patient 52: X-ray detector 54: Grid 58: Photodetector array 62: Driver 80: Photodetector 82: Switching thin film transistor (TFT) 84: Bias power supply 85: Bias power supply 92: Line selector 100: Signal readout circuit 122 , 130, 131: Electromagnetic shield

──────────────────────────────────────────────────の Continued on the front page (51) Int.Cl. ⁷ Identification symbol FI Theme coat ゛ (Reference) H04N 5/225 H04N 5/32 5/32 H01L 27/14 K F term (Reference) 2G088 EE01 FF02 GG19 GG21 JJ05 JJ09 JJ21 KK32 LL11 LL12 LL24 4C093 AA01 CA06 CA41 EA14 EB02 EB12 EB17 EB25 EB26 ED04 EE01 EE11 FA32 FA43 FC03 FD01 FD05 FF01 FF03 FF50 FG05 FH04 FH06 4M118 AB01 BA09 CA02 CB50

Claims (28)

[Claims] A detecting unit for detecting an image of a subject; an electromagnetic shield unit; and a driving unit for moving at least one of the detecting unit and the electromagnetic shielding unit. The driving unit transmits a signal from the detecting unit. An image pickup apparatus, wherein when reading is performed, at least one of the detection unit and the electromagnetic shield unit is moved so that the detection unit is covered with the electromagnetic shield unit. A detecting unit for detecting a subject image; an electromagnetic shielding unit; and a driving unit for moving at least one of the detecting unit and the electromagnetic shielding unit. The driving unit transmits a signal from the detecting unit. The electromagnetic wave to the detecting means when is read out is smaller than the electromagnetic wave to the detecting means when the detecting means is detecting the subject image, at least the detecting means and the electromagnetic shield portion An imaging device, characterized in that one of them is moved. 3. The driving means moves the detecting means, wherein the detecting means has a position at which a subject image is stored and a position at which a signal is read, and wherein the signal is read when the signal is read. The imaging apparatus according to claim 1, wherein the detection unit is covered with the electromagnetic shield at a position. 4. The imaging device according to claim 1, wherein the electromagnetic shield is a magnetic shield. 5. The electromagnetic shield according to claim 1, wherein the electromagnetic shield has an opening for enclosing the detection means, and has a structure capable of covering the opening.
The imaging device according to any one of the above. 6. The detection means has a second electromagnetic shield part covering a part thereof, and the detection means is provided with the second electromagnetic shield part.
The imaging device according to any one of claims 1 to 4, further comprising a structure in which the detection unit is covered with the electromagnetic shield part. 7. Detecting means for detecting an image of an object, and detecting the electromagnetic wave to the detecting means when reading out a signal from the detecting means when the detecting means accumulates the image of the object. An electromagnetic wave blocking unit having a function of reducing the number of electromagnetic waves to the unit. 8. The imaging apparatus according to claim 7, wherein the electromagnetic wave blocking unit has an electromagnetic shield for covering the detection unit. 9. An image forming apparatus comprising: a detecting unit configured to detect an object image; and an electromagnetic wave blocking unit configured to cover the detecting unit with an electromagnetic shield when reading out a signal from the detecting unit. Imaging device. 10. A detecting means for detecting an image of a subject, and an electromagnetic wave blocking means having a function of reducing electromagnetic waves to the detecting means, wherein the detecting means and the electromagnetic wave are used when reading a signal from the detecting means. Moving at least one of the blocking means,
An imaging device characterized in that both positions are superimposed. 11. The imaging apparatus according to claim 10, wherein the electromagnetic wave blocking unit has an electromagnetic shield for covering the detection unit. 12. The apparatus according to claim 7, wherein the electromagnetic wave blocking means has an opening for enclosing the detection means and an electromagnetic shield having a structure capable of covering the opening. 12. The imaging device according to any one of items 11 to 11. 13. The electromagnetic wave shielding means includes an electromagnetic shield part having an opening for enclosing the detection means,
The said detection means has the 2nd electromagnetic shield part which covers a part, and has the structure which the said detection means is covered with the said electromagnetic shield part and the said 2nd electromagnetic shield part. The imaging device according to any one of 7 to 11. 14. The apparatus according to claim 7, wherein said detecting means is movable with respect to said electromagnetic wave blocking means.
14. The imaging device according to any one of claims 13 to 13. 15. The apparatus according to claim 7, wherein said electromagnetic wave blocking means is movable with respect to said detecting means.
14. The imaging device according to any one of claims 13 to 13. 16. An imaging apparatus for selectively performing fluoroscopic imaging and general imaging using X-rays, wherein said electromagnetic wave blocking unit transmits an electromagnetic wave to said detection unit when said detection unit reads a signal in said general imaging. The imaging device according to any one of claims 7 to 15, wherein the imaging device is reduced. 17. An imaging method for detecting an image of a subject, the method comprising: storing an electromagnetic wave to the detecting means at the time of reading a signal from the detecting means for detecting the subject image; An imaging method, wherein the number of electromagnetic waves is smaller than the amount of electromagnetic waves to the detection means at the time. 18. The imaging method according to claim 17, wherein at the time of reading the signal, the detection unit is covered with an electromagnetic shield. 19. The apparatus according to claim 17, wherein a position of said detection means at the time of said reading is made different from a position of said detection means at the time of said accumulation, and said detection means is covered with an electromagnetic shield part at said reading. Or the imaging method according to 18. 20. The apparatus according to claim 19, wherein the position of the electromagnetic shield at the time of reading is different from the position of the electromagnetic shield at the time of accumulation, and the detecting means is covered with the electromagnetic shield at the time of reading. Item 19. The imaging method according to Item 17 or 18. 21. An imaging apparatus for imaging a subject using radiation, comprising: detecting means for detecting a radiation image of the subject; and a radiation source for radiating an electromagnetic wave when reading a signal from the detecting means. And control means for setting the state of the device to a state in which radiation of electromagnetic waves is reduced. 22. The imaging device according to claim 21, wherein the radiation source is an image display. 23. The imaging device according to claim 21, wherein the radiation source is an X-ray generator. 24. The state in which the radiation of the electromagnetic wave is reduced,
The imaging apparatus according to any one of claims 21 to 23, wherein power supply to the radiation source is stopped or reduced. 25. An imaging method for imaging an object using radiation, comprising: a step of reading a signal from a means for detecting a radiation image of the object by reducing a radiation source that emits electromagnetic waves to reduce radiation of the electromagnetic waves; An imaging method characterized in that the imaging state is changed to a state in which the imaging state is changed. 26. The imaging method according to claim 25, wherein the radiation source is an image display. 27. The imaging method according to claim 25, wherein the radiation source is an X-ray generator. 28. The state in which the radiation of the electromagnetic wave is reduced,
The imaging method according to any one of claims 25 to 27, wherein power supply to the radiation source is stopped or reduced.