JPH11188021A - X-ray surface sensor and X-ray imaging apparatus - Google Patents

Abstract

(57) [Summary] [PROBLEMS] To prevent a transmitted X-ray image from being sufficiently sharp and unnecessarily enlarged. An X-ray imaging apparatus according to the present invention uses, as a sensor for detecting a transmitted X-ray image, a thin flat panel X-ray sensor (3) in which X-ray detection elements (4) are arrayed vertically and horizontally. Since the exposure sensor 5a is a configuration using a thin film type X-ray exposure sensor integrally installed on the back surface of the panel type X-ray sensor 3, X-rays are not scattered by the X-ray exposure sensor 5a and are clear. Since a transparent X-ray image can be obtained and the distance between the subject and the panel-type X-ray sensor 3 is shortened, the transmitted X-ray image is not unnecessarily enlarged.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to an X-ray radiography system.
BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an X-ray imaging apparatus using an X-ray imaging apparatus using the X-ray imaging apparatus.
The present invention relates to a technique for performing automatic exposure control for stopping X-ray irradiation when a dose reaches a predetermined set amount.

[0002]

2. Description of the Related Art FIG. 10 shows a conventional X-ray imaging apparatus.
It is a schematic diagram which shows the situation at the time of line imaging. A conventional X-ray imaging apparatus includes an X-ray tube 91 for irradiating a patient M with X-rays, and a film cassette 9 in which a film 92 for X-ray imaging is loaded.
3 and a grid 94 for removing scattered X-rays and an X-ray exposure sensor 95 for detecting an irradiation X-ray dose for performing automatic exposure control in front of the film cassette 93. A film density setting unit 96 for presetting a proper irradiation X-ray dose (exposure time), and an automatic exposure control unit for stopping X-ray irradiation when the actual irradiation X-ray dose (actual irradiation X-ray dose) reaches a predetermined set amount. 97 is provided.

The X-ray exposure sensor 95 is, as shown in FIG. 11, a transparent acrylic piece 95b-9m having a thickness of several millimeters.
An acrylic substrate 95a formed by bonding 5d to form one rectangular plate-like body, and three phosphor films 95e to 95b provided in a rectangular pattern on the surface of the acrylic substrate 95a.
95g, and three photomultiplier tubes 95h to 95j provided at the edge of the acrylic substrate 95a.
The surfaces and bonding surfaces of the transparent acrylic pieces 95b to 95d are all light reflecting surfaces except for the portions facing the photomultiplier tubes 95h to 95j.

Then, light is generated in the phosphor films 95e to 95g in response to the transmitted X-rays during X-ray photography. The light generated in the phosphor film 95e is guided to the photomultiplier tube 95h, and The light generated on the film 95f is guided to the photomultiplier tube 95i, and the light generated on the phosphor film 95g is guided to the photomultiplier tube 95j. As a result, the intensity of the transmitted X-rays from each of the photomultiplier tubes 95h to 95j is reduced. An output signal corresponding to the output is transmitted. Normally, photomultiplier tube 95 for chest imaging
Output signals of h and 95j are used, and in the case of body-side imaging, an output signal of the photomultiplier tube 95i is used.

When performing X-ray imaging using the X-ray imaging apparatus shown in FIG. 10, an X-ray tube 91 and a film 92 are arranged so as to face each other with a patient M interposed therebetween. The line is irradiated on the patient M. Then, the intensifying screen (not shown) in the film cassette 93 emits light by the transmitted X-ray, and the film 92 is exposed. On the other hand, an output signal corresponding to the intensity of the transmitted X-ray is transmitted from the X-ray exposure sensor 95 to the automatic exposure control unit 97 and integrated, and the integrated value of the output signal corresponding to the X-ray irradiation amount is set to the film density setting. Part 9
When the preset amount is reached, the automatic exposure control section 97 outputs a command signal to stop irradiation to the irradiation control section 98. Upon receiving the irradiation stop command signal, the irradiation control unit 98 sets X
The X-ray irradiation of the tube 91 is immediately stopped. The transmission X-ray image of the patient M is transferred onto the film 92 in the film cassette 93 at an appropriate density by the automatic exposure control, and the X-ray imaging is completed.

[0006]

However, in the case of the above-mentioned conventional X-ray imaging apparatus, the sharpness of the transmitted X-ray image projected on the film 92 is insufficient depending on the kind of an affected part to be imaged. Or the transmitted X-ray image is unnecessarily enlarged. The lack of sharpness of the transmitted X-ray image is caused by the fact that the X-ray exposure sensor 95 behind the scattered X-ray removal grid 94 has a considerable thickness. This is because the transmitted X-ray image is blurred because X-rays are slightly scattered. Unnecessarily magnifying the transmitted X-ray image is also due to the fact that the X-ray exposure sensor 95 is also quite thick, increasing the distance between the patient M and the film 92, and as a result, geometrically. This is because the image is enlarged and photographed.

The present invention has been made in view of the above circumstances, and provides an X-ray surface sensor and an X-ray imaging apparatus in which a transmitted X-ray image is clear and the transmitted X-ray image is not unnecessarily enlarged. That is the task.

[0008]

In order to achieve the above object, an X-ray surface sensor according to the first aspect of the present invention converts transmitted X-rays incident upon irradiation of an X-ray onto a subject to be imaged into electric charges. In an X-ray surface sensor for transmitting X-ray images in which X-ray detection elements for direct conversion are arranged vertically and horizontally, transmitted X-rays incident on the front surface or the back surface of the X-ray surface sensor along with X-ray irradiation are emitted. A thin-film X-ray exposure sensor is formed by laminating an X-ray / light conversion thin layer for converting light into light and a photoelectric conversion thin layer for converting light converted by the X-ray / light conversion thin layer into an electric signal. It is installed in.

Further, in order to achieve the above object, the present invention is directed to claim 2
The X-ray surface sensor according to the invention of
X-ray plane sensors for transmitting X-ray images, in which X-ray detection elements for converting the transmitted X-rays incident upon irradiation with X-rays and converting the converted light into electric charges are arranged vertically and horizontally,
A thin-film X-ray exposure sensor having a photoelectric conversion thin layer on the front or back surface of a line sensor for converting converted light generated by the X-ray detection element by transmitted X-rays incident upon X-ray irradiation into an electric signal. Are installed integrally.

[0010] In order to achieve the above object, a third aspect is provided.
An X-ray imaging apparatus according to the present invention is an X-ray tube for irradiating a subject with X-rays, and an X-ray sensor for detecting a transmitted X-ray image disposed to face the X-ray tube across the subject. An automatic exposure control means for stopping the X-ray irradiation when the irradiation X-ray amount reaches a predetermined set amount, and an X-ray exposure sensor for detecting the irradiation X-ray amount necessary for the automatic exposure control. In the X-ray imaging apparatus, as the X-ray sensor, an X-ray that directly converts transmitted X-rays incident upon irradiation of the subject with X-rays into electric charges is used.
An X-ray surface sensor in which X-ray detection elements are arrayed vertically and horizontally is provided, and as the X-ray exposure sensor, transmitted X-rays incident on the front or back surface of the X-ray surface sensor with X-ray irradiation A thin-film X-ray exposure sensor comprising a stack of an X-ray / light conversion thin layer that converts light into light and a photoelectric conversion thin layer that converts light converted by the X-ray / light conversion thin layer into an electric signal. It is installed integrally.

[0011] In order to achieve the above object, the present invention is directed to claim 4.
An X-ray imaging apparatus according to the present invention is an X-ray tube for irradiating a subject with X-rays, and an X-ray sensor for detecting a transmitted X-ray image disposed to face the X-ray tube across the subject. An automatic exposure control means for stopping the X-ray irradiation when the irradiation X-ray amount reaches a predetermined set amount, and an X-ray exposure sensor for detecting the irradiation X-ray amount necessary for the automatic exposure control. In the X-ray imaging apparatus, as the X-ray sensor, an X-ray detection element that first converts transmitted X-rays incident upon irradiation of an X-ray to a subject to be X-rayed into light, and converts the converted light into electric charge Are arranged vertically and horizontally, and as the X-ray exposure sensor, a transmission X-ray incident on the front surface or the back surface of the X-ray surface sensor along with X-ray irradiation is provided.
A thin-film type X-ray exposure sensor having a photoelectric conversion thin layer for converting converted light generated by the X-ray detection element into an electric signal by a line is integrally provided.

[Operation] Next, the operation at the time of X-ray imaging using the X-ray surface sensor or X-ray imaging apparatus of the present invention will be described. In the case of the X-ray surface sensor according to the first aspect, when X-rays for X-ray imaging are irradiated, the X-ray detection elements arranged vertically and horizontally are accompanied by X-ray irradiation to the subject to be imaged. The incident transmitted X-rays are directly converted into electric charges, and X
Line detection data (image signal) is generated in each X-ray detection element.
In a thin-film X-ray exposure sensor integrally installed on the front or back surface of an X-ray surface sensor, first, transmitted X-rays incident upon X-ray irradiation are converted into light by a thin X-ray / light conversion layer. Then, the light converted by the photoelectric conversion thin layer is converted into an electric signal for detecting the irradiation X-ray dose. Since the electric signal itself is a signal having an intensity corresponding to the X-ray intensity, an actual irradiation X-ray dose can be detected by integrating the electric signal.

In the case of the X-ray surface sensor of the present invention, when X-rays for X-ray imaging are irradiated, each of the X-ray detecting elements arranged vertically and horizontally irradiates the X-ray to the subject to be imaged. Then, the transmitted X-rays incident thereon are first converted into light, and then the converted light is converted into electric charges to generate X-ray detection data (image signal) for the transmitted X-ray image. Also, a thin film type X which is integrally installed on the front surface or the back surface of the X-ray surface sensor
In the line exposure sensor, the photoelectric conversion thin layer converts the converted light generated by the X-ray detection element (accurately, a part of the converted light) into an electric signal for detecting the irradiated X-ray dose. Since the electric signal itself is a signal corresponding to the X-ray intensity, the X-ray dose can be detected by integrating the electric signal.

In the case of X-ray imaging by the X-ray imaging apparatus of the third aspect, an X-ray surface sensor for detecting a transmitted X-ray image in which X-ray detecting elements are arranged vertically and horizontally and an X-ray tube are sandwiched between the subject. When the X-ray tube irradiates the subject with X-rays from the X-ray tube, the X-ray surface sensor outputs X-ray detection data along with the X-ray irradiation on the subject. An X-ray fluoroscopic image is obtained. On the other hand, an output signal having a signal intensity corresponding to the X-ray intensity is sent to the automatic exposure control means from the thin-film X-ray exposure sensor integrally provided on the front surface or the rear surface of the X-ray surface sensor. In the automatic exposure control means, X
While detecting the irradiation X-ray dose by integrating the output signal of the X-ray exposure sensor, when the irradiation X-ray dose reaches a predetermined set amount, X-ray irradiation by the X-ray tube is stopped,
X-ray imaging is completed.

In the case of X-ray imaging by the X-ray imaging apparatus according to the present invention, an X-ray plane sensor for detecting a transmitted X-ray image in which X-ray detecting elements are arranged vertically and horizontally and an X-ray tube are sandwiched between the subject. When the X-ray tube irradiates the subject with X-rays from the X-ray tube, the X-ray surface sensor outputs X-ray detection data along with the X-ray irradiation on the subject. An X-ray fluoroscopic image is obtained. On the other hand, an output signal having a signal intensity corresponding to the X-ray intensity is also sent from the thin-film X-ray exposure sensor integrally provided on the front surface or the rear surface of the X-ray surface sensor to the automatic exposure control means. The automatic exposure control means detects the irradiation X-ray by integrating the output signal of the X-ray exposure sensor, and stops the X-ray irradiation by the X-ray tube when the irradiation X-ray reaches a predetermined set amount. , X-ray photography is completed.

The X-ray surface sensor according to the first to fourth aspects of the present invention is thin, and the integrated X-ray exposure sensor is also thin with a thin film laminated structure. Since it is located immediately behind the line removal grid, scattered X-rays are sufficiently removed, and the distance between the subject and the X-ray surface sensor is shortened, so that unnecessary enlargement of the X-ray fluoroscopic image is performed. Can be suppressed.

[0017]

Next, an embodiment of the present invention will be described with reference to the drawings. Figure 1 shows a flat panel type X
FIG. 2 is a block diagram showing an overall configuration of an X-ray imaging apparatus using a X-ray sensor (X-ray surface sensor). FIG. FIG. 3 is a plan view showing an arrangement of the line detection elements, and FIG. 3 is a plan view showing an X-ray exposure sensor installed on the back surface of the panel type X-ray sensor.

The X-ray imaging apparatus shown in FIG. 1 includes an X-ray tube 1 for irradiating a patient M with X-rays, and a grid 2 for removing scattered X-rays so as to face the X-ray tube 1 with the patient M interposed therebetween. A panel type X-ray sensor 3 for detecting a transmitted X-ray image is provided immediately after. In the panel type X-ray sensor 3, as shown in FIG. 2, a large number of X-ray detection elements 4 for directly converting transmitted X-rays incident upon irradiation of the patient M with X-rays into electric charges are arranged vertically and horizontally. As shown in FIG. 3, X-ray exposure sensors 5a to 5c for detecting the irradiation X-ray dose required for automatic exposure control are integrally formed on the back surface of the panel-type X-ray sensor 3 in a strip-shaped pattern shape. Is formed.

A signal collecting unit 6 that collects X-ray detection data output from the panel X-ray sensor 3 and sends the data to the image processing unit 7 is provided downstream of the panel X-ray sensor 3. An image processing unit 7 subsequent to the signal collecting unit 6 includes an AD conversion unit 8 that converts the X-ray detection data into a digital signal.
A detection data memory 9 for storing digitized X-ray detection data, and data for creating an X-ray image by performing necessary image processing such as edge enhancement and filtering on the X-ray detection data stored in the detection data memory 9 The apparatus includes a processing unit 10 and an X-ray image memory 11 for storing the obtained X-ray image. Normally, during X-ray fluoroscopy, the X-ray images stored in the X-ray image memory 11 are continuously updated one after another.

The X-ray tube 1 is configured to irradiate a patient M with X-rays according to set irradiation conditions such as a tube voltage and a tube current under the control of an irradiation control unit 12 including a high voltage generator and the like. The control by the irradiation control unit 12 is as follows.
This is performed in accordance with a command signal sent from the photographing control unit 15 in accordance with a setting operation from the keyboard 13 or the mouse 14 and a command signal sent from the automatic exposure mechanism described below.

The X-ray imaging apparatus according to the embodiment has the following automatic exposure mechanism. The automatic exposure mechanism includes an X-ray exposure sensor 5a to 5c for outputting an output signal (electric signal) having a signal intensity proportional to the transmitted X-ray intensity, and a panel type X-ray sensor 3
X-ray dose setting unit 16 for presetting an appropriate X-ray dose taking into account the detection sensitivity of the X-ray, and the actual X-ray dose (actual X-ray dose) set by the X-ray dose setting unit 16 And an automatic exposure control unit 17 for sending a command signal to stop the X-ray irradiation to the irradiation control unit 12 when it reaches. The setting of the irradiation X-ray by the irradiation X-ray setting unit 16 is performed according to a command signal transmitted from the imaging control unit 15 in accordance with the setting operation from the keyboard 13 and the mouse 14.

Since the output signals of the X-ray exposure sensors 5a to 5c have a signal intensity proportional to the transmitted X-ray intensity, the automatic exposure controller 17 integrates the output signals of the X-ray exposure sensors 5a to 5c by the capacitor 17a. The actual irradiation X-ray is calculated by the comparator 17b, and the actual irradiation X-ray is compared with the preset amount by the irradiation X-ray setting unit 16 by the comparator 17b. Upon reaching, an irradiation stop command signal is output from the automatic exposure control unit 17 to the irradiation control unit 12.

On the other hand, the X-ray imaging apparatus of the embodiment has an image display monitor 18 and is configured to display an X-ray image stored in the X-ray image memory 11. There is also provided an image printing recording unit (leather imager) 19 for printing an X-ray image stored in a film onto a film and outputting it as an image photograph, and an electronic image storage memory 20 for storing and storing the X-ray image signal as it is. ,
The X-ray image stored in the X-ray image memory 11 is displayed on the image display monitor 18 in accordance with a command signal sent from the imaging control unit 15 in response to an operation input from the keyboard 13 or the mouse 14.
To be displayed on the display, sent out as an image photograph from the image printing recording unit 19, or stored and held in the image storage memory 20.

Next, the configuration of the X-ray detecting element 4 of the panel type X-ray sensor 3 will be specifically described. The arrangement of the X-ray detection elements 4 in the panel X-ray sensor 3 includes, for example, a square matrix configuration in a horizontal (X) direction 1024 and a vertical (Y) direction 1024. The plane dimension of the panel type X-ray sensor 3 is, for example, about 30 cm in length and width. The panel-type X-ray sensor 3 has many advantages such as little image distortion around the image, high resolution, and extremely thin and lightweight.

As shown in FIG. 4, the panel type X-ray sensor 3 detects an X-ray conversion layer 30 for converting incident X-rays into charges (electrons and holes), and detects charges generated in the X-ray conversion layer 30. This is a so-called direct conversion type sensor having a laminated structure with the detection array layer 31 in which elements to be formed are arranged vertically and horizontally in a matrix. In the case of this direct conversion type, as shown in FIG. 5, the X-ray conversion layer 30 is made of a selenium layer or a CdZnTe layer which directly converts incident X-rays into electric charges. The charge is detected by a charge collecting electrode formed on the surface of the glass substrate 31a so as to face the surface electrode 33 and stored in the capacitor C1, and the stored charge is stored in the TFT (Thin F).
Each of the charge detection elements 32, a part of the X-ray conversion layer 30, the capacitor C 1 and the TFT 34 constitute one X-ray detection element 4. Is formed.

In the panel type X-ray sensor 3, FIG.
, Each of the X-ray detection elements 4,.
The read lines 36 and 37 are connected to a horizontal read drive unit 38 or a vertical read drive unit 39, respectively, and are connected to a horizontal / vertical read drive unit via an FT 34. Scanning signals for reading are sent to 38 and 39. Panel type X
The identification of each X-ray detecting element 4 of the line sensor 3 is performed based on the addresses 0 to 1023 sequentially assigned to each X-ray detecting element 4 along the horizontal and vertical arrangements. Are the signals for designating a horizontal address or a vertical address, respectively.

According to the horizontal / vertical scanning signals, the readout wiring 36,
As the voltage for reading is applied to 37, an X-ray detection signal is sequentially output from each of the detecting elements 4,.
4, the data passes through the readout wiring 37, and is further collected as fluoroscopic X-ray detection data via the preamplifiers 40 and the multiplexer 41 of the signal collection unit 6.

From the above, it can be said that the method of reading out the detection signal from the panel type X-ray sensor 3 is almost the same as that of a video detector such as a normal TV camera. In the case of the embodiment, both read-out drive units 38 and 39 constituting the signal collection unit 6
In addition, the preamplifier 40 and the multiplexer 41 are also provided on the periphery of the surface of the detection array layer 31 of the panel type X-ray sensor 3, and have a configuration that is further integrated. The detection data memory 9 for storing X-ray detection data obtained from the panel type X-ray sensor 3 and the X-ray image memory 11 for storing X-ray images are provided by the X-ray detection elements 4 of the panel type X-ray sensor 3. A frame memory type storage device having a matrix configuration corresponding to the vertical and horizontal matrix configuration is used.

Next, the configuration of the X-ray exposure sensors 5a to 5c integrally provided on the back surface of the panel type X-ray sensor 3 will be specifically described. As shown in FIG. 5, the X-ray exposure sensors 5a to 5c have a structure sequentially stacked on the back surface of the glass substrate 31a, that is, an element electrode layer 42 of aluminum or carbon and an amorphous semiconductor layer 43 of amorphous silicon or the like. And a transparent electrode layer 44 made of ITO (indium tin oxide) or the like, and a phosphor layer 45 made of calcium tungstate or gadolinium oxysulfide / terbium. With this stacking order, the phosphor layer 45 having relatively low heat resistance is deposited last, which is convenient.

The element electrode layer 42, the amorphous semiconductor layer 43, and the transparent electrode layer 44 are formed by a thin film forming method such as a sputtering deposition method or a CVD method, and the phosphor layer 45 is formed by coating. . The element electrode layer 42 and the transparent electrode layer 44 have a thickness of several μm, the amorphous semiconductor layer 43 and the phosphor layer 45 have a thickness of several tens μm to several hundred μm, and the thickness of the entire thin film structure, that is, X Line exposure sensor 5a
The total thickness as 5c can be suppressed as very thin as 500 μm or less.

In the case of the X-ray exposure sensors 5 a to 5 c, the transmitted X-rays are converted into light by the phosphor layer (photoelectric conversion thin layer) 45 and the amorphous semiconductor layer (X-ray / light conversion thin layer) 43.
The converted light is converted into an electric signal by the above, and this electric signal is output as an output signal from the printed wirings 5d to 5f through the connector 5g as shown in FIG.
Sent to Normally, the X-ray exposure sensors 5a and 5c are for chest imaging, and the X-ray exposure sensor 5b is for body-side imaging.

In the above example, the X-ray exposure sensors 5a to 5c are provided on the back surface of the panel X-ray sensor 3, but the X-ray exposure sensors 5a to 5c are provided on the front surface of the panel X-ray sensor 3. Is also good. However, when the X-ray exposure sensors 5a to 5c are provided on the surface of the panel X-ray sensor 3, when the energy of the incident X-ray is low, the shadows of the X-ray exposure sensors 5a to 5c are included in the transmitted X-ray image. May appear. Panel type X
It is preferable to provide the X-ray exposure sensors 5a to 5c on the back surface of the line sensor 3 because such inconvenience does not occur.

Next, the operation of the apparatus when X-ray photography is performed by the apparatus having the above-described configuration will be described with reference to FIG.
This will be described with reference to the flowchart shown in FIG.

[Step S1] As shown in FIG. 1, a panel-type X-ray sensor 3
Set so that is positioned.

[Step S2] Next, the irradiation X-ray dose set by the irradiation X-ray dose setting unit 16 is input in advance from the keyboard 13 or the mouse 14.

[Step S3] The keyboard 13
Alternatively, when imaging is started by an input operation from the mouse 14, X-rays are emitted from the X-ray tube 1 to the patient M.

[Step S4] The data output from the panel type X-ray sensor 3 along with the X-ray irradiation is stored in the detection data memory 9, and the X-ray exposure sensors 5a, 5c
Is output from the capacitor 17 of the automatic exposure controller 17.
a.

[Step S5] As long as the actual irradiation X-ray dose obtained by integration of the condenser 17a of the automatic exposure control unit 17 does not reach the set amount, X-ray irradiation is continued and the data processing unit 1
0, image data processing is performed, an X-ray fluoroscopic image is projected and displayed on the screen of the monitor 18, and a necessary image is stored in the image storage memory 20, or
It is output as an image photograph by the image printing recording unit 19.

[Step S6] When the actual irradiation X-ray amount obtained by integration of the condenser 17a of the automatic exposure control unit 17 reaches the set amount, the automatic exposure control unit 17 sends an irradiation stop command signal to the irradiation control unit 12. Sent out.

[Step S7] Upon receiving the irradiation stop command signal, the irradiation control unit 12 immediately shuts off the X-ray irradiation by the X-ray tube 1, and the X-ray imaging ends.

Next, another embodiment of the present invention will be described. FIG. 8 is a cross-sectional view showing the configuration of a panel-type X-ray sensor according to another embodiment, and FIG. 9 is a plan view showing an X-ray exposure sensor installed on the surface of the panel-type X-ray sensor.

The panel type X-ray sensor 3 has a so-called indirect conversion in which the X-ray detection elements 46 arranged vertically and horizontally first convert incident transmitted X-rays into light, and convert the converted light into electric charges. Type. It is also possible to configure an X-ray imaging apparatus in which such an indirect conversion type panel X-ray sensor is used in place of the direct conversion type panel X-ray sensor shown in FIG.

In the case of this panel type X-ray sensor 3 of the indirect conversion type, as shown in FIG.
A glass substrate 31a as a light detecting element 35 in the detection array layer 31;
The photodiode formed above detects light and stores the light in the capacitor C1.
Each of the light detection elements 35 and a part of the X-ray conversion layer 30 thereon are extracted through the FT 34.
One X-ray detecting element 46 is formed by the capacitor C1 and the TFT 34. The connection structure of each X-ray detection element 46 and the configuration of the read-out drive unit are the same as those of the panel type X-ray sensor shown in FIG.

On the other hand, in the panel type X-ray sensor 3 of this embodiment, as shown in FIG.
a to 47c are integrally provided in a strip-shaped pattern. The X-ray exposure sensors 47a to 47c include the X-ray conversion layer 30.
A transparent electrode layer 48 such as ITO, an amorphous semiconductor layer 49 such as amorphous silicon, and an element electrode 5 such as aluminum or carbon.
0 and a thin-film laminated structure composed of zero. The transparent electrode layer 48, the amorphous semiconductor layer 49, and the device electrode layer 50 are formed by a thin film forming method such as a sputtering deposition method or a CVD method.
Has a thickness of several μm, and the amorphous semiconductor layer 49 has a thickness of several tens μm.
m to several hundred μm, and the total thickness of the entire thin film laminated structure, that is, the total thickness of the X-ray exposure sensors 47a to 47c is 5
The thickness can be suppressed to a very small value of 00 μm or less.

The detection operation of the X-ray exposure sensors 47a to 47c is as follows. Light generated in the X-ray conversion layer 30 due to X-ray irradiation passes through the transparent electrode layer 48 and the amorphous semiconductor layer 49.
And is converted into an electric signal. The electric signal is output as an output signal as shown in FIG.
It is sent from 7f to the automatic exposure controller 17 via the connector 47g. Usually, the X-ray exposure sensors 47a and 47c are for chest imaging, and the X-ray exposure sensor 47b is for body-side imaging. Although the X-ray exposure sensors 47a to 47c may be provided on the back surface of the panel type X-ray sensor 3, the glass substrate 3
Since 1a is interposed therebetween, the amount of light incident on the amorphous semiconductor layer 49 is slightly reduced.

The present invention is not limited to the above embodiment, but can be modified as follows. (1) Although the X-ray imaging apparatus according to the embodiment includes the image display monitor, the image printing recording unit, and the image storage memory as image display / output means, it is not necessary to include all of them. For example, an apparatus having a configuration including only one of an image display monitor, an image printing recording unit, and an image storage memory is a modified example.

(2) In the case of the X-ray imaging apparatus of the embodiment, three X-ray exposure sensors are provided, but the number of X-ray exposure sensors does not need to be a specific number. A configuration in which only one sensor is provided is also a modified example.

[0048]

According to the X-ray surface sensors of the first and second aspects described above, the X-ray surface sensor for detecting transmitted X-rays is thin, and at the same time, the surface of the X-ray surface sensor or Since the X-ray exposure sensor for detecting the irradiation X-ray which is integrally installed on the back side is also a thin type having a thin film laminated structure,
X-rays are hardly scattered due to the line exposure sensor, and when X-ray imaging is performed, a sufficiently clear transmitted X-ray image can be obtained. Further, the distance between the subject and the X-ray surface sensor is reduced, and the transmitted X-ray image is not unnecessarily enlarged.

Further, according to each of the X-ray imaging apparatuses of the third and fourth aspects, the X-ray surface sensor for detecting a transmitted X-ray image, which is disposed to face the X-ray tube with the subject interposed therebetween, is thin. At the same time, the X-ray exposure sensor for detecting the amount of irradiated X-rays, which is provided integrally with the front or back surface of the X-ray surface sensor for performing the automatic exposure control, has a thin thin film laminated structure, so that X-ray scattering is small. Thus, a sufficiently clear transmitted X-ray image can be obtained. Further, the distance between the subject and the X-ray surface sensor is reduced, and the transmitted X-ray image is not unnecessarily enlarged.

[Brief description of the drawings]

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

FIG. 2 is a plan view showing an arrangement of X-ray detection elements of a panel-type X-ray sensor of the example device.

FIG. 3 is a plan view showing an X-ray exposure sensor installed on the back surface of the panel type X-ray sensor of the embodiment.

FIG. 4 is a perspective view illustrating a schematic configuration of a panel X-ray sensor according to the embodiment.

FIG. 5 is a cross-sectional view illustrating a layer structure of a panel-type X-ray sensor and an X-ray exposure sensor according to an example.

FIG. 6 is a block diagram illustrating a circuit configuration around a panel-type X-ray sensor according to the embodiment.

FIG. 7 is a flowchart showing a series of flows of an X-ray imaging operation according to the embodiment.

FIG. 8 is a cross-sectional view illustrating a layer structure of a panel-type X-ray sensor and an X-ray exposure sensor according to another embodiment.

FIG. 9 is a plan view showing an X-ray exposure sensor installed on the surface of a panel-type X-ray sensor according to another embodiment.

FIG. 10 is a schematic diagram showing a situation at the time of X-ray imaging by a conventional X-ray imaging apparatus.

FIG. 11 is a plan view showing a configuration of a conventional X-ray exposure sensor.

[Explanation of symbols]

1 ... X-ray tube 3 ... Flat panel type X
Line sensors 4, 46 X-ray detecting elements 5a to 5c, 47a to 47c X-ray exposure sensor 7 Image processing unit 17 Automatic exposure control unit 30 X-ray conversion layer 31 Detection array layer 43, 49 Amorphous Quality semiconductor 45 ... phosphor layer M ... patient

Claims (4)

[Claims] 1. An X-ray plane for transmitting X-ray images, wherein X-ray detecting elements for directly converting transmitted X-rays incident upon irradiation of an X-ray onto a subject to be imaged into electric charges are arranged vertically and horizontally. In the sensor, an X-ray / light conversion thin layer for converting transmitted X-rays incident on the front or back surface of the X-ray surface sensor upon irradiation with X-rays into light, and the X-ray / light conversion thin layer is used for conversion. An X-ray surface sensor, wherein a thin-film X-ray exposure sensor formed by laminating a photoelectric conversion thin layer for converting light into an electric signal is integrally provided. 2. An X-ray transmission device in which transmitted X-rays incident upon X-ray irradiation on a subject to be imaged are first converted into light, and X-ray detection elements for converting the converted light into electric charges are arranged vertically and horizontally. X
In an X-ray surface sensor for X-ray imaging, a photoelectric conversion device converts converted light generated by the X-ray detection element into an electric signal by transmitted X-rays incident on the front surface or the back surface of the X-ray surface sensor along with X-ray irradiation. An X-ray surface sensor for X-ray imaging, wherein a thin-film X-ray exposure sensor having a conversion thin layer is integrally provided. 3. An X-ray tube for irradiating an object with X-rays, an X-ray sensor for detecting a transmitted X-ray image disposed to face the X-ray tube across the object, and an irradiation X-ray dose An automatic exposure control means for stopping X-ray irradiation when a predetermined set amount is reached, and an X-ray imaging apparatus including an X-ray exposure sensor for detecting an irradiation X-ray dose required for automatic exposure control,
As the X-ray sensor, an X-ray surface sensor in which X-ray detection elements that directly convert transmitted X-rays incident upon irradiation of the subject with X-rays into electric charges are arranged vertically and horizontally is provided, An X-ray / light conversion thin layer that converts transmitted X-rays incident on the front or back surface of the X-ray surface sensor along with X-ray irradiation into light, and an X-ray / light conversion thin layer as an X-ray exposure sensor An X-ray imaging apparatus characterized in that a thin-film X-ray exposure sensor, which is formed by laminating a photoelectric conversion thin layer that converts light converted by the above into an electric signal, is integrally installed. 4. An X-ray tube for irradiating an object with X-rays, an X-ray sensor for detecting a transmitted X-ray image disposed opposite to the X-ray tube across the object, and an irradiation X-ray dose An automatic exposure control means for stopping X-ray irradiation when a predetermined set amount is reached, and an X-ray imaging apparatus including an X-ray exposure sensor for detecting an irradiation X-ray dose required for automatic exposure control,
As the X-ray sensor, X-ray detection elements that first convert transmitted X-rays incident upon X-ray irradiation to an X-ray imaging target object into light and convert the converted light into electric charges are arranged vertically and horizontally. X-ray surface sensor is provided.
As the X-ray exposure sensor, the X-ray is transmitted by a transmitted X-ray incident on the front surface or the back surface of the X-ray surface sensor along with X-ray irradiation.
An X-ray imaging apparatus characterized in that a thin-film X-ray exposure sensor including a photoelectric conversion thin layer for converting converted light generated by a line detection element into an electric signal is integrally provided.