JPH09140691A - X-ray photographing apparatus - Google Patents

Abstract

PROBLEM TO BE SOLVED: To accurately take an X-ray photograph by obliquely radiating X-rays for a desired time optionally timely in the state where an X-ray detector is continuously working by reconstructing an X-ray picture image by adding electric charge data read out from each of X-ray detecting elements in every X-ray detecting element. SOLUTION: An apparatus comprises plural frame memories 4-1, 4-2,..., a memory controlling unit 3 for storing each of photographing data from the frame at the beginning time of X-ray radiation to the frame next to the finishing time of the X-ray radiation, based on X-ray signal, by selecting respectively different frame memories and an X-ray picture image reconstructing means 5 for reconstructing the X-ray picture image by performing addition processing and average processing of X-ray picture images at each image elements. Thereby, in the state where an X-ray detector 1 is continuously working, X-ray radiation can be performed for a desired time optionally timely and all of effectively photographed data are made to be rightly used under avoiding waste and accurate X-ray picture image improved in S/N ratio can be obtained.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an X-ray imaging apparatus using an X-ray detector composed of a plurality of X-ray detecting elements for accumulating detected X-rays as electric charges.

[0002]

2. Description of the Related Art An X-ray imaging apparatus irradiates a subject with X-rays, detects X-rays transmitted through the subject with an X-ray detector, and captures an image of the transmitted X-rays. . recent years,
As an X-ray imaging device, the portability of screen film systems and imaging plates
The high resolution characteristics of the screen system, and I. -TV
TFT that combines the real-time nature of the system
An X-ray semiconductor flat panel detector using (thin film transistor) as a switching gate has been developed.

In this X-ray semiconductor flat panel detector, a fluorescent substance for converting X-rays into light, a photodiode for converting the light into an electric charge, a capacitor for accumulating the electric charge, and the electric charge are read out on a flat plate-shaped detection surface ( It is composed of TFTs for outputting, and photodiodes (and capacitors, TFTs) are arranged two-dimensionally (in a plane) in an array.

That is, as shown in FIG.
A gate electrode 102 is formed in the plurality of TFT regions on the first TFT, and a SiNx layer 103 is formed thereon. This Si
On the Nx layer 103, a.Si layer 10 is provided in the TFT area.
4 and the drain electrode 105 and the source electrode 106 are formed. The drain electrode 105 and the source electrode 106 are connected via the a.Si layer 104 so that they do not come into direct contact with each other.

Further, n + a.Si layers 107 and 108 are formed in the gaps between the a.Si layer 104 and the drain electrode 105 and the source electrode 106. As described above, the TFT is formed in the TFT area.

On the other hand, the SiNx layer 103 and the source electrode 106 are formed in a plurality of PD regions on the support 101, and the n + layer 109, the i layer 110,
A photodiode having a pin structure formed of the p + layer 111 is formed.

A first polyimide resin layer 112 is formed on the TFT, and a transparent electrode 113 is formed on the photodiode. A metal electrode 114 that connects the transparent electrodes 113 of the photodiode is formed on the first polyimide resin layer 112.
The metal electrode 114 also has a function of preventing light from entering the TFT.

The transparent electrode 113 and the metal electrode 11
A second polyimide resin layer 115 is formed on the surface 4. A transparent protective film 116, a phosphor 117, and a light reflection layer 118 are formed on the second polyimide resin layer 115.

The photodiode and the TFT
Are connected in a circuit manner as shown in FIG. The photodiode 121 is connected in parallel with a capacitor (hereinafter referred to as storage capacitor) 122, and the anode terminal of the photodiode 121 and the storage capacitor 1 are connected.
22 is connected to the reverse bias power supply (-Vn), and the connection point between the cathode terminal of the photodiode 121 and the storage capacitor 122 is connected to the source terminal of the TFT 123 (source electrode 106). There is. As the capacitor (for storage) described here, the electrostatic capacity of the photodiode 121 may be used, or when the electrostatic capacity of the photodiode 121 is insufficient, an additional capacitance is added. It is a good thing to add to.

As will be described later, the gate terminal of the TFT 123 is connected to the gate drive line, and the drain terminal thereof is connected to the data signal line. In this way, one X-ray detection element is configured, and the X-ray detection elements are two-dimensionally arranged to configure an X-ray semiconductor flat panel detector.

FIG. 10 is a circuit diagram showing a main configuration of an X-ray semiconductor flat panel detector. The X-ray semiconductor flat panel detector has an X-ray detection element 124 (the TFT 123 may be included in the X-ray detection element) composed of the photodiode 121 and the capacitor 122 as one element, and arrayed in columns and lines. Are arranged two-dimensionally.

Further, the gate terminal of the TFT 123 is commonly connected as a gate drive line for each line, and is connected to each line output terminal of the gate driver 125. The drain terminal of the TFT 124 is commonly connected as a data signal line for each column, and includes a read-out amplifier, a capacitor (hereinafter, referred to as a time constant capacitor), and a reset switch (not shown) for resetting. ) Is connected to each input terminal of the multiplexer 127.

From each line output terminal of the gate driver 125, a pulsed control signal is sequentially output in time series, and the pulsed control signal simultaneously turns on the TFTs 123 on the same line. The TFTs 123 on different lines are turned on so that they are not sequentially overlapped in time series.

The multiplexer 127 takes in the signals inputted to the respective input terminals during one pulse outputted from the respective line output terminals of the gate driver 125 one by one in a time series and outputs them. It is designed to output from the terminal.

Therefore, when the pulse control signals output from the respective line output terminals of the gate driver 125 simultaneously turn on the TFTs 123 for one line,
The charge stored in the storage capacitor 122 is applied to the TFT 12
The charge is converted into a voltage through the integrating circuit 126, and then output by the multiplexer 127 one by one (each pixel in one line).
When the reading of one line is completed in this way, the reading of the next line is started.

That is, like a scanning line of a television, each X-ray detecting element 124 is read one by one (one pixel at a time) for each line, and a detection signal is read in order to obtain image data for one screen (video signal). Is output as.
It should be noted that one frame is a period in which image data for one screen is read from the X-ray semiconductor flat panel detector.

In the X-ray semiconductor flat panel detector having such a structure, X-rays that have passed through the subject from above pass through the light reflection layer 118 and enter the phosphor 117. At this time, visible light incident from above is reflected by the light reflection layer 118 and is not incident on the phosphor 117.

The energy of incident X-rays is converted into light energy (visible light) by the phosphor 117, and this visible light is transmitted through the transparent protective film 116 and the second polyimide resin layer 115, and further through the transparent electrode 113. And a photodiode 121 (n + layer 109, i layer 110, which is sensitive to visible light)
The light is received by the p + layer 111).

The energy of the incident X-ray is converted by the photodiode 121 into a charge amount proportional to the intensity of light and stored in the storage capacitor 122. As described above, the accumulated charges are read out by the TFT 123 through the data signal line line by line in pixel unit (column by column). The read signal is proportional to the intensity of the X-ray, and an X-ray image can be reproduced by reconstructing the read signal in pixel units.

Furthermore, a method for timing the X-ray exposure and the reading of image data from the X-ray semiconductor flat panel detector is as follows:
There are two methods: In the first method, as shown in FIG. 11 (a), in the case of 1-shot photography (one-photographing), the X-ray semiconductor flat panel detector (detector) is not read periodically and completely stopped. Every other time, the X-ray semiconductor flat panel detector is driven at the timing when the X-ray exposure is finished to read the imaged data.

The data line output is strictly a pixel.
The accumulated charge for each (X-ray detection element) is a signal output through the integration circuit 126 and is sequentially output in a time series, but here, for simplicity, these respective signals are continuously output. Shows.

The second method, as shown in FIG. 11 (b), is to provide a blanking period for stopping the driving of the X-ray semiconductor flat panel detector, like a normal video signal, to provide an X-ray semiconductor flat panel detector. When X is continuously driven periodically, X-ray irradiation is performed within the blanking period.

[0023]

In the first method, X-ray irradiation can be performed at arbitrary timing.
There is a problem that it is necessary to control the drive timing of the X-ray semiconductor flat panel detector in accordance with the timing of the radiation exposure.

In the second method, it is not necessary to control the drive timing of the X-ray semiconductor flat panel detector, but the X-ray exposure timing is adjusted in accordance with the blanking period of the drive timing of the X-ray semiconductor flat panel detector. There is a problem in that the X-ray exposure time is limited to the blanking period.

Therefore, according to the present invention, X-ray imaging is possible in which the X-ray detector can be continuously driven and X-ray irradiation can be performed for a desired time at an arbitrary timing, and an accurate X-ray image can be obtained. The purpose is to provide a device.

[0026]

The invention corresponding to claim 1 is:
In an X-ray imaging apparatus using an X-ray detector composed of a plurality of X-ray detection elements for accumulating detected X-rays as electric charges, charges accumulated from all X-ray detection elements of the X-ray detector. X-ray detection by the reading means for continuously reading frames as a period for sequentially reading the X-rays, and the reading means from the frame at the start of X-ray exposure to the frame next to the frame at the end of X-ray exposure. Reconstructing means for reconstructing an X-ray image by adding charge data from the elements for each X-ray detecting element is provided.

The invention corresponding to claim 2 is the invention according to claim 1, wherein the X-ray detecting element includes a photodiode and a thin film transistor. According to a third aspect of the invention, in an X-ray imaging device using an X-ray detector including a plurality of X-ray detection elements that accumulate detected X-rays as charges, the X-ray detection element of the X-ray detector is provided. Read-out means for continuously reading out frames as a period for sequentially reading out the accumulated charges from all of the above, and read-out means from the next frame at the start of X-ray exposure to the frame at the end of X-ray exposure. Read-out stopping means for stopping the reading of the charge data from each X-ray detecting element, and each X-ray read by the continuous reading means for the frame at the start of X-ray exposure and the frame next to the frame at the end of X-ray exposure. Reconstruction means for reconstructing an X-ray image by adding charge data from the detection elements for each X-ray detection element is provided.

The invention corresponding to claim 4 is the X according to claim 3.
In the X-ray imaging device, the X-ray detection element includes a photodiode and a thin film transistor. Claim 5
The corresponding invention is an X-ray imaging apparatus using an X-ray detector composed of a plurality of X-ray detection elements for accumulating detected X-rays as electric charges, and an X-ray is detected from the next frame at the start of X-ray exposure. Read-out stopping means for stopping the reading of the charge data from each X-ray detection element until the frame at the end of the X-ray exposure, and each X of the frame at the start of the X-ray exposure and the next frame at the end of the X-ray exposure. Reconstructing means for reconstructing an X-ray image by adding the charge data read out from the line detection elements are provided.

According to a sixth aspect of the invention, in an X-ray imaging apparatus using an X-ray detector composed of a plurality of X-ray detecting elements for accumulating the detected X-rays as electric charges, an X-ray detector has an X-ray detector. Readout means for continuously reading out a frame as a period for sequentially reading out charges accumulated from all of the line detection elements, and a frame next to the frame at the start of X-ray exposure to the frame at the end of X-ray exposure. Up to the first reconstructing means for reconstructing an X-ray image by adding the charge data from each X-ray detecting element read by the reading means up to each X-ray detecting element. Reading stop means for stopping the reading of the charge data from each X-ray detection element by the reading means from the frame of X to the frame at the end of the X-ray exposure;
Secondly, the X-ray image is reconstructed by adding the charge data from each X-ray detecting element read by the reading means in the frame at the time of starting the radiation exposure and at the next frame at the end of the X-ray exposure.
Reconstructing means, and a selecting means for selecting either the first reconstructing means or the second reconstructing means. When the first reconstructing means is selected by this selecting means, the read stopping means and the first reconstructing means are provided. The operation by the second reconstructing means is stopped, and the operation by the first reconstructing means is stopped when the second reconstructing means is selected by the selecting means.

[0030]

DETAILED DESCRIPTION OF THE INVENTION A first embodiment of the present invention will be described with reference to FIGS. FIG. 1 is a block diagram showing a main configuration of an X-ray imaging apparatus to which the present invention is applied until an X-ray image is reconstructed. The other configuration of the X-ray imaging apparatus is the same as the configuration of a general X-ray imaging apparatus, and the description thereof is omitted here.

Reference numeral 1 is an X-ray semiconductor flat panel detector (a plurality of X-ray flat panel detectors composed of photodiodes, capacitors and TFTs, which are two-dimensionally arranged in a plane, and X-rays are arranged on the flat panel. With a phosphor that converts light into light,
It is an X-ray detector using (see FIGS. 8 to 10). Each one screen output from this X-ray detector 1 (1 frame
The analog image pickup signal (serial signal) is input to the A / D converter 2. The image pickup signal is converted into digital image pickup data by the A / D converter 2, and the first frame memory 4-1, the second frame memory 4-2, and the third frame are passed through the memory control unit 3. The memories 4-3, ... Are supplied to and stored in a memory unit composed of n frame memories.

The memory control unit 3 is adapted to change the frame memory as a supply destination of digital image pickup data according to an X-ray signal indicating whether or not X-ray irradiation is performed. As a method for generating the X-ray signal, although not shown, for example, there is a method described below.

The first method is a method of directly connecting to an X-ray tube apparatus for generating X-rays and irradiating an object (subject), and inputting the X-ray irradiation drive signal as an X-ray signal. Second
In this method, an X-ray sensor made of a material that hardly absorbs X-rays is installed on the X-ray incident surface of the X-ray detector, and the X-ray detection signal from this X-ray sensor is used as the X-ray signal. For example, ABC (auto brightness control) and AE
There are C (Auto X Vosage Control) etc.

The third method is to install an X-ray sensor for detecting X-rays on the back surface (side surface opposite to the X-ray incidence surface) of the X-ray detector, and to let X-rays leak to the back surface of this X-ray detector. Is detected, the X-ray detection signal from the X-ray sensor is converted into the X-ray signal. The fourth method uses one of the X-ray detection elements of the X-ray semiconductor flat panel detector (1 pixel, one on the edge side of the reading range) of the X-ray detector as an X-ray sensor, and In this method, the detection signal of is an X-ray signal.

The fifth method uses a plurality (for example, one line or one row) of X-ray detecting elements of the X-ray semiconductor flat panel detector of the X-ray detector as X-ray sensors, and these X-ray detecting elements are used. This is a method of generating an X-ray signal from the detection signal from.
The sixth method is a method in which an ammeter for detecting a current (driving current for generating X-rays) flowing in an X-ray tube is installed and an output signal from the ammeter is used as an X-ray signal.

In the first and subsequent embodiments, the method of generating the X-ray signal may be any of the above, or another method may be used. is there.

When the X-ray signal obtained by any of the above methods is a signal indicating that X-ray irradiation is not performed, the memory control section 3 receives the input from the A / D converter 2. Of the digital image data is supplied to the first frame memory 4-1. In the first frame memory 4-1, the supplied image data is sequentially overwritten and stored.

When the X-ray signal becomes a signal indicating that the X-ray is being radiated, the image data output from the A / D converter 12 is changed frame by frame from the frame next to the frame at that time. The frame memory of the supply destination is sequentially changed to the second frame memory 4-2, the third frame memory 4-3, ....

Then, when the X-ray signal changes from a signal indicating that the X-ray is being emitted to a signal indicating that the X-ray is not being emitted, that is, when the X-ray exposure is finished, this X-ray exposure is performed. The above-mentioned change of the frame memory of the supply destination is continued until the frame next to the frame at the end of shooting, and the supply destination of the imaging data of the next frame is returned to the first frame memory 4-1 again.

Here, for example, the frame memory in which the image data of the frame next to the frame at the end of X-ray exposure is stored is referred to as the xth frame memory. When the writing of the imaging data to the xth frame memory is completed, the X-ray image reconstruction is performed from the imaging data stored in the first frame memory 4-1 to the imaging data stored in the xth frame memory. The unit 5 adds the pixels pixel by pixel and averages them to be reconstructed as one X-ray image. This reconstructed X-ray image is output to an output device such as a display or a storage device such as a hard disk.

In the first embodiment having such a structure, X-ray imaging is performed by performing X-ray irradiation at an arbitrary timing in a state where the X-ray detector 1 is normally driven continuously and periodically. To do. For example, a case where X-ray irradiation shorter than one frame is performed based on the timing shown in FIG. 2 will be described.

At time t1 when X-ray irradiation is started, X
One frame of digital imaging data A1 output from the line detector 1 via the A / D converter 2 is stored in the memory control unit 3
Is stored in the first frame memory 4-1 via the. Even at the time point t2 when the X-ray exposure is finished, the digital image data output from the X-ray detector 1 through the A / D converter 2 is the image data A1 of the same frame as above,
Therefore, it is still stored in the first frame memory 4-1.

The digital image data A2 of the frame next to the frame at the time point t2 when the X-ray irradiation is finished is stored in the second frame memory 4-2 via the memory control unit 3.

When the writing of the image pickup data A2 to the second frame memory 4-2 is completed, the X-ray image reconstructing section 5 causes the image pickup data of the first frame memory 4-1 and the second frame memory 4-2. The image pickup data of 4-2 is added pixel by pixel and averaged to reconstruct one X-ray image. In addition, in this X-ray image reconstruction, it is not necessary to perform averaging only by adding. This also applies to the subsequent embodiments.

Further, based on the timing shown in FIG.
A case where X-ray irradiation longer than one frame is performed will be described. At time t3 when the X-ray exposure is started, one frame of digital image data B1 output from the X-ray detector 1 via the A / D converter 2 is transferred to the first frame via the memory control unit 3. It is stored in the memory 4-1.

Regarding the image data B2 of the next frame and the subsequent image data B3, B4, and B5, since the X-ray irradiation is in progress, the image data B is sequentially passed through the memory control unit 3.
2 is stored in the second frame memory 4-2, the imaging data B3 is stored in the third frame memory 4-3, the imaging data B4 is the fourth frame memory, and the imaging data B5 is the fifth.
Stored in the frame memory.

In the next frame, since the X-ray exposure is completed (time point t4), the imaging data B6 at that time point t4 is also stored in the sixth frame memory, and the X
The imaging data B7 of the frame next to the frame at the time point t4 when the line exposure is completed is also stored in the next seventh frame memory.

When the writing of the imaging data B7 of the frame next to the frame at the time point t4 when the X-ray exposure is finished to the seventh frame memory, the X-ray image reconstructing unit 5 causes the first frame memory. The image data of 4-1 to the image data of the seventh frame memory are added for each pixel and averaged (the average process may not be performed), and one X-ray image is reconstructed.

As described above, according to the first embodiment, the plurality of frame memories 4-1, 4-2, ... And the X-ray from the frame at the time of the start of X-ray exposure based on the X-ray signal. The memory control unit 3 for selecting and storing different frame memories for the image data of each frame up to the frame next to the frame at the end of exposure, and the image data of each frame memory are subjected to arithmetic mean processing for each pixel. By providing the X-ray image reconstruction unit 5 for reconstructing an X-ray image with the X-ray image, it is possible to perform X-ray irradiation for a desired time at an arbitrary timing while the X-ray detector 1 is continuously driven. Moreover, it is possible to obtain an accurate X-ray image with improved S / N by utilizing all effective imaging data without waste.

A second embodiment of the present invention will be described with reference to FIG. FIG. 4 is a block diagram showing a main configuration of an X-ray imaging apparatus to which the present invention is applied until an X-ray image is reconstructed. The other configuration of the X-ray imaging apparatus is the same as the configuration of a general X-ray imaging apparatus, and the description thereof is omitted here.

Each one screen output from the X-ray detector 11
(1 frame) analog imaging signal (serial signal)
Is input to the A / D converter 12. The image pickup signal is converted into digital image pickup data by the A / D converter 12 and supplied to the main memory 14 via the adder 13. In the main memory 14, the sequentially supplied image pickup data is overwritten. Remembered.

The adder 13 reads the image pickup data stored in the main memory 14 by an X-ray signal indicating whether or not X-ray irradiation is performed, and the A / D converter 1
2 and the image pickup data supplied from each pixel are added, and the result is supplied to the main memory 14 again.
Then, the imaging data sequentially supplied is overwritten and stored.

That is, when the X-ray signal is a signal indicating that X-ray irradiation is not performed, the imaging data output from the A / D converter 12 is not read out from the main memory 14. As it is the main memory 1
4, and the main memory 14 overwrites and stores the sequentially supplied imaging data. When the X-ray signal becomes a signal indicating that X-ray irradiation is performed, the imaging data is read from the main memory 14 and the A / D converter 12 is read.
The image pickup data supplied from the above is added for each pixel, and the result is supplied to the main memory 14 again. In the main memory 14, the added image pickup data is overwritten and stored.

When the X-ray signal changes from a signal indicating that the X-ray is being emitted to a signal indicating that the X-ray is not being emitted, that is, when the X-ray exposure is completed, the X-ray exposure is completed. The image data is read from the main memory 14 until the frame next to the current frame, and the A / D converter 12 is read.
The image pickup data supplied from the above is added for each pixel, and the result is supplied again to the main memory 14. In the main memory 14, the supplied image pickup signal is overwritten and stored.

When the writing of the image data of the frame next to the frame at the end of the X-ray exposure to the main memory 14 is completed, the image data stored in the main memory 14 is converted into the X-ray image reconstruction unit. The average processing is performed by 15 and reconstructed as one X-ray image. This reconstructed X-ray image is output to an output device such as a display or a storage device such as a hard disk.

In the second embodiment having such a structure, X-ray imaging is performed by performing X-ray irradiation at an arbitrary timing in a state where the X-ray detector 11 is normally driven continuously and continuously. To do. For example, based on the timing shown in FIG.
A case where X-ray irradiation shorter than the frame is performed will be described.

At time t1 when the X-ray irradiation is started, X
One frame of digital image pickup data A1 output from the line detector 11 via the A / D converter 12 is added by the adder 13
It is stored in the main memory 14 as it is without being subjected to the addition processing via. Even at the time t2 when the X-ray exposure is finished,
The digital image pickup data output from the X-ray detector 11 via the A / D converter 12 is the image pickup data A1 of the same frame as described above, and thus is stored in the main memory 14.

The digital image pickup data A2 of the frame next to the frame at the time point t2 when the X-ray exposure is finished is added to the image pickup data (A1) read from the main memory 14 by the adder 13 to be added to the main memory 14. Memorized in. Then, the imaging data (
When the writing of the image pickup data obtained by adding the image pickup data A1) to the main memory 14 is completed, the X-ray image reconstructing unit 15 performs an averaging process to reconstruct one X-ray image.

Further, based on the timing shown in FIG.
A case where X-ray irradiation longer than one frame is performed will be described. At the time point t3 when the X-ray exposure is started, one frame of the digital image data B1 output from the X-ray detector 11 via the A / D converter 12 is subjected to addition processing via the adder 13. Main memory 1
4 is stored.

Regarding the image data B2 of the next frame and the subsequent image data B3, B4, and B5, since the X-ray irradiation is being performed, the image data B2 is stored in the main memory 14 by the sequential adder 13. The image data B 1 is added and stored in the main memory 14, and the image data B
3 is the imaging data (B
1 + B2) and stored in the main memory 14,
The image data B4 is added to the image data (B1 + B2 + B3) stored in the main memory to obtain the main memory 1
4 and the image pickup data B5 is added to the image pickup data (B1 + B2 + B3 + B4) stored in the main memory 14 and stored in the main memory 14.

In the next frame, the X-ray exposure is completed (time point t4), so the image data B6 at the time point t4 is also the image data stored in the main memory 14 (
B1 + ... + B5) and stored in the main memory 14. Further, the imaging data B7 of the frame next to the frame at the time point t4 when the X-ray irradiation is finished is also the imaging data (B1 + ... + B) stored in the main memory 14.
6) and stored in the main memory 14.

When the writing of the image data B7 of the frame next to the frame at the time point t4 when the X-ray exposure is completed to the main memory 14, the X-ray image reconstruction unit 15 is completed.
Is averaged to reconstruct one X-ray image.

As described above, according to the second embodiment, the main memory 14 and the next frame from the frame at the start time of X-ray exposure to the frame at the end time of X-ray exposure based on the X-ray signal. An adder 13 for sequentially adding the image pickup data up to the frame and storing it in the main memory 14, and the main memory 1.
By providing the X-ray image reconstructing unit 15 for averaging the cumulatively added imaging data stored in No. 4 and reconstructing an X-ray image, the same effect as that of the first embodiment described above can be obtained. Obtainable. Furthermore, one main memory 14
Since the X-ray image reconstruction unit only needs to perform the averaging process, the memory capacity can be reduced and X
This has the effect of reducing the processing load of the line image reconstruction unit 15.

A third embodiment of the present invention will be described with reference to FIG. FIG. 5 is a block diagram showing a main configuration of an X-ray imaging apparatus to which the present invention is applied until an X-ray image is reconstructed. The other configuration of the X-ray imaging apparatus is the same as the configuration of a general X-ray imaging apparatus, and the description thereof is omitted here.

Each one screen output from the X-ray detector 21
(1 frame) analog imaging signal (serial signal)
Is input to the A / D converter 22. The image pickup signal is converted into digital image pickup data by the A / D converter 22, and is supplied to and stored in the first frame memory 24-1 or the second frame memory 24-2 via the memory control unit 23. To be done.

The gate driver 21-1 for controlling the driving of reading the image pickup signal in the X-ray detector 21 emits X-rays from the signal indicating that the X-rays are not X-rays. When the X-ray exposure is started, that is, when the X-ray exposure is started, the driving of reading the image pickup signal of the X-ray detector 21 is stopped from the frame next to the frame at the start of the X-ray irradiation. X from the signal indicating that the exposure
When it becomes a signal indicating that it is not exposed to radiation, that is, X
When the radiation exposure ends, the driving of reading the image pickup signal of the X-ray detector 21 is restarted from the frame next to the frame at the end.

During the period in which the gate driver 21-1 does not drive the X-ray detector 21 to read the image signal, the X-ray detecting elements accumulate charges according to the dose of X-rays. It is being continued.

The memory control section 23 is adapted to change the frame memory to which digital image pickup data is supplied based on the X-ray signal. That is, when the X-ray signal is a signal indicating that X-ray irradiation is not performed, the memory control unit 23 receives the input digital image data from the A / D converter 22 as the first frame memory. 24
-1, and the first frame memory 24-1 sequentially overwrites and stores the supplied imaging data.

Further, when the X-ray signal changes from a signal indicating that the X-ray is not being emitted to a signal indicating that the X-ray is being emitted, that is, at the time of starting the X-ray emission, the frame following the start is displayed. Image data output from the A / D converter 22 from the frame No. 2 to the second frame memory 24-2, and the second frame memory 24-2 overwrites the image data sequentially supplied. Remember.

When the X-ray signal changes from a signal indicating that the X-ray is being emitted to a signal indicating that the X-ray is not being emitted, that is, at the end of the X-ray exposure, the next frame after the end. Image data of the second frame memory 24-2 is supplied to the second frame memory 24-2, and image data of the next frame is supplied to the first frame memory 24-1. In 1, the imaging data sequentially supplied is overwritten and stored.

When the writing of the image pickup data to the second frame memory 24-2 is completed, the image pickup data stored in the first frame memory 24-1 and the second frame memory 24-2 becomes X. The X-ray image reconstructing unit 25 adds each pixel and averages them to reconstruct one X-ray image. This reconstructed X-ray image is output to an output device such as a display or a storage device such as a hard disk.

In the third embodiment having such a structure, X-ray imaging is performed by performing X-ray irradiation at an arbitrary timing in a state where the X-ray detector 1 is normally driven continuously and continuously. To do. For example, a case where X-ray irradiation longer than one frame is performed based on the timing shown in FIG. 6 will be described. The X-ray irradiation shorter than one frame is the same as that in the first embodiment described above, and thus the description thereof is omitted.

At time t5 when the X-ray exposure is started, X
One frame of digital imaging data C1 output from the line detector 21 via the A / D converter 22 is stored in the first frame memory 24-1 via the memory controller 23. At this time, the gate driver 21-1 causes the time t
From the next frame of 5, the driving of the X-ray detector 21 to read the image pickup signal is stopped. In this embodiment, when the driving of the X-ray detector 21 is stopped, the A / D converter 2
When the driving of No. 2 is stopped and the driving of the X-ray detector 21 is restarted, the driving of the A / D converter 22 is also restarted in synchronization.

At the time point t6 when the X-ray exposure is completed, the gate driver 21-1 restarts driving the X-ray detector 21 from the frame following the frame at the time point t6. At the time of restarting, one frame of digital imaging data C output from the X-ray detector 21 via the A / D converter 22.
2 is stored in the second frame memory 24-2 via the memory control unit 23.

When the writing of the image data C2 of the frame next to the frame at the time point t6 when the X-ray exposure is finished to the second frame memory 24-2, the X-ray image reconstructing unit 25 makes the first The image data stored in the frame memory 24-1 and the second frame memory 24-2 are added for each pixel and averaged to reconstruct one X-ray image.

As described above, according to the third embodiment, when the X-ray exposure is started based on the X-ray signal, the reading drive of the X-ray detector 21 is stopped and the X-ray exposure is completed. Then, the gate driver 21-1 restarts the reading drive of the X-ray detector 21 from the frame next to the current frame.
And the first frame memory 24-1 and the second frame memory 24-2, and the image data of the frame at the start point of the X-ray exposure based on the X-ray signal.
-1 and the first frame memory 24-1 and the memory control unit 23 that stores the imaging data of the frame next to the frame at the end of the X-ray exposure in the second frame memory 24-2.
And the X-ray image reconstructing unit 25 that reconstructs an X-ray image by adding the imaged data of the second frame memory 24-2 for each pixel and averaging the pixels, thereby continuously connecting the X-ray detector 1. In the driven state, X-ray irradiation can be performed at a desired time for a desired time, and an accurate X-ray image can be obtained.

Moreover, in the third embodiment, since the image pickup signal necessary for reconstructing the X-ray image can be obtained from the X-ray detector 21 twice, the noise due to this reading is reduced. Therefore, an X-ray image with less noise can be obtained. Further, since the number of times of addition processing is reduced by accumulating charges by the X-ray detection element, the processing load on the X-ray image reconstruction unit 25 and the like can be reduced.

A fourth embodiment of the present invention will be described with reference to FIG. FIG. 7 is a block diagram showing a main configuration of an X-ray imaging apparatus to which the present invention is applied until an X-ray image is reconstructed. The other configuration of the X-ray imaging apparatus is the same as the configuration of a general X-ray imaging apparatus, and the description thereof is omitted here.

Each one screen output from the X-ray detector 31
(1 frame) analog imaging signal (serial signal)
Is input to the A / D converter 32. The image pickup signal is converted into digital image pickup data by the A / D converter 32, and the first frame memory 34-1, the second frame memory 34-2, and the third frame are passed through the memory control unit 33. The memories 34-3, ... Are supplied to and stored in a memory unit including a plurality of frame memories.

The gate driver 31-1, which controls the driving of reading the image pickup signal in the X-ray detector 31, detects the X-ray from the signal indicating that the X-ray signal from the mode determination unit 35 is not exposed to X-ray. When it becomes a signal indicating that the X-ray is exposed, the driving for reading the image pickup signal of the X-ray detector 31 is stopped from the frame next to the frame at that time, and the X-ray signal from the mode determination unit 35 is exposed to the X-ray. When the signal indicating that the X-ray is not emitted from the signal indicating that the X-ray is emitted, the X-ray detector 31 starts from the frame next to the frame at that time.
The driving of reading the image pickup signal is restarted.

During the period in which the gate driver 31-1 stops driving the X-ray detector 31 to read the image signal, the X-ray detecting elements accumulate electric charge according to the X-ray dose. It is being continued.

When the driving of the X-ray detector 31 to read the image signal is stopped, the driving of the A / D converter 32 is also stopped and the driving of the X-ray detector 31 to read the image signal is restarted. Then, the driving of the A / D converter 32 is also restarted in synchronization.

The memory control unit 33 includes a mode determination unit 3
Based on the X-ray signal from 5, the frame memory to which the digital image data is supplied is changed.
That is, when the X-ray signal from the mode determination unit 35 is a signal indicating that X-ray irradiation is not performed, the memory control unit 33 outputs the input digital image data from the A / D converter 32. The image data is supplied to the first frame memory 34-1, and the supplied image data is sequentially overwritten and stored in the first frame memory 34-1.

When the X-ray signal from the mode determination unit 35 changes from a signal indicating that X-ray is not being emitted to a signal indicating that X-ray is being emitted, the frame next to the frame at this time From the A / D converter 32, the frame memory of the supply destination is set to the second frame memory 34-2, the third frame memory 34-3, ... It will be changed sequentially.

When the X-ray signal from the mode determining unit 35 changes from a signal indicating that X-rays are being emitted to a signal indicating that X-rays are not being emitted, the next frame of the frame at this time is displayed. The above-mentioned change of the frame memory of the supply destination is continued until the image pickup data of the next frame, and the supply destination of the image data of the next frame is again the first frame memory
Return to -1.

Here, for example, the frame memory in which the image data of the frame next to the frame at the end of X-ray exposure is stored is referred to as the xth frame memory. When the writing of the image pickup data to the xth frame memory is completed, the image pickup data stored in the first frame memory 34-1 to the image pickup data stored in the xth frame memory are
The X-ray image reconstruction unit 36 adds each pixel and averages them to reconstruct one X-ray image. This reconstructed X-ray image is output to an output device such as a display or a storage device such as a hard disk.

The mode determination unit 35 uses a manual switch (not shown) for switching between the mode corresponding to the above-described first embodiment and the mode corresponding to the above-described third embodiment, or the use thereof. An X-ray signal indicating whether or not X-ray irradiation is performed is supplied only to the memory control unit 33 or is supplied to the memory control unit 33 based on the X-ray dose, the region to be imaged, and the like. It is also supplied to the gate driver 31-1.

In the fourth embodiment having such a structure, the mode corresponding to the first embodiment described above is set by the manual switch, or when the X-ray dose to be used is large, the X-ray dose to be used is large. When shooting,
The mode determination unit 35 outputs the X-ray signal to the memory control unit 33.
Supplied only to Therefore, as in the first embodiment described above, from the frame at the start of X-ray exposure to the frame next to the frame at the end of X-ray exposure, image data is stored in different frame memories for each frame. The X-ray image is stored, and the image pickup data of each frame memory is added for each pixel and averaged to reconstruct one X-ray image.

In addition, when the X-ray dose to be used is small in the mode corresponding to the above-mentioned second embodiment by the manual switch, or when the portion of the X-ray dose to be used is imaged, the mode determination unit 35 is used. , X-ray signals are supplied to the memory control unit 33 and the gate driver 31-1
Is also supplied.

Therefore, as in the above-described second embodiment, the image data of the frame at the start of X-ray exposure is stored in the first frame memory 34-1, and the X-ray exposure is performed from the next frame. The driving of the X-ray detector 31 and the A / D converter 32 is stopped until the irradiation ends, and the X-ray detector 31 and the A / D converter start from the frame next to the frame at the end of the X-ray irradiation. 32 is restarted, and the image data of the frame next to the frame at the end of the X-ray exposure is stored in the second frame memory 3
Remember in 4-2. Then, the first frame memory 3
The image pickup data of 4-1 and the second frame memory 34-2 are added pixel by pixel and averaged to reconstruct one X-ray image.

As described above, according to the fourth embodiment, the mode determining section for selectively switching between the photographing processing method of the first embodiment and the photographing processing method of the second embodiment described above. By providing 35, operator's request,
Optimal imaging processing operations can be performed according to the application such as the X-ray dose used and the part to be imaged. As a result, S
It is possible to obtain the same effect as that of the above-described first embodiment for improving / N or the same effect as that of the above-described third embodiment for reducing noise.

[0092]

As described in detail above, according to the present invention,
With the X-ray detector continuously driven, X-ray irradiation can be performed for a desired time at an arbitrary timing, and an accurate X-ray can be obtained.
An X-ray imaging device capable of obtaining a line image can be provided.

[Brief description of the drawings]

FIG. 1 is a block diagram showing a main configuration of an X-ray imaging apparatus according to a first embodiment of the present invention until an X-ray image is reconstructed.

FIG. 2 is a diagram showing timings of X-ray exposure and an X-ray detector in a time shorter than one frame in the first embodiment and the second embodiment.

FIG. 3 is a diagram showing timings of X-ray exposure and an X-ray detector for a time longer than one frame in the first embodiment and the second embodiment.

FIG. 4 is a block diagram showing a main configuration of an X-ray imaging apparatus according to a second embodiment of the present invention until an X-ray image is reconstructed.

FIG. 5 is a block diagram showing a main configuration of an X-ray imaging apparatus according to a third embodiment of the present invention until an X-ray image is reconstructed.

FIG. 6 is a view showing timings of X-ray exposure and an X-ray detector for a time longer than one frame in the embodiment.

FIG. 7 is a block diagram showing a main configuration of an X-ray imaging apparatus according to a fourth embodiment of the present invention until an X-ray image is reconstructed.

FIG. 8 is a cross-sectional view showing a main part structure of an X-ray detection element forming an X-ray semiconductor flat panel detector.

FIG. 9 is a circuit diagram showing an X-ray detection element forming an X-ray semiconductor flat panel detector.

FIG. 10 is a circuit diagram showing a main configuration of an X-ray semiconductor flat panel detector.

FIG. 11 is a diagram showing a timing of X-ray irradiation and driving of an X-ray detector in a conventional example.

[Explanation of symbols]

1, 11, 21, 31, ... X-ray detector, 2, 12, 22, 32 ... A / D converter, 3, 23, 33 ... Memory control unit, 13 ... Adder, 4-1, 4-2, 4-3, ~, 24-1, 24-2, 34-1, 34
-2, 34-3, ... Frame memory, 14 ... Main memory, 5, 15, 25, 36 ... X-ray image reconstruction unit, 35 ... Mode determination unit.

Front page continuation (72) Inventor Akira Tsukamoto 1385-1 Shimoishigami, Otawara-shi, Tochigi Stock Company Toshiba Nasu factory (72) Inventor Shinichi Yamada 1385-1 Shimoishi, Otawara-shi, Tochigi Toshiba Nasu Inside the factory (72) Inventor Tohru Saisu 1385-1 Shimoishikami, Otawara, Tochigi Prefecture Toshiba Nasu Factory (72) Inside Takayuki Tomisaki 1385-1 Shimoishi, Otawara City, Tochigi Toshiba Nasu Factory (72) Inventor Manabu Tanaka 1385-1 Shimoishigami, Otawara-shi, Tochigi, Toshiba Nasu Factory (72) Inventor Seiichiro Nagai 1385-1 Shimoishi, Otawara, Tochigi Toshiba Medical Engineering Co., Ltd.

Claims (6)

[Claims] 1. An X-ray imaging apparatus using an X-ray detector comprising a plurality of X-ray detection elements for accumulating detected X-rays as electric charges, comprising: Reading means for continuously reading frames as a period for sequentially reading the accumulated charges from all, and the reading from the frame at the start of X-ray exposure to the frame next to the frame at the end of X-ray exposure. An X-ray imaging device, comprising: reconstructing means for reconstructing an X-ray image by adding the charge data from each of the X-ray detecting elements read by the means for each of the X-ray detecting elements. 2. The X-ray imaging apparatus according to claim 1, wherein
The X-ray imaging device, wherein the X-ray detection element includes a photodiode and a thin film transistor. 3. An X-ray imaging apparatus using an X-ray detector, which comprises a plurality of X-ray detection elements for accumulating detected X-rays as electric charges, comprising: A reading means for continuously reading frames as a period for sequentially reading the accumulated charges from all, and the reading means from the next frame at the start of X-ray exposure to the frame at the end of X-ray exposure. Read stop means for stopping the reading of the charge data from each of the X-ray detection elements; and the continuous read means for reading the frame at the start of X-ray exposure and the frame next to the frame at the end of X-ray exposure. An X-ray imaging apparatus, comprising: reconstructing means for reconstructing an X-ray image by adding charge data from each X-ray detecting element to each of the X-ray detecting elements. 4. The X-ray imaging apparatus according to claim 3,
The X-ray imaging device, wherein the X-ray detection element includes a photodiode and a thin film transistor. 5. An X-ray image pickup apparatus using an X-ray detector comprising a plurality of X-ray detection elements for accumulating detected X-rays as electric charges, wherein X from the next frame at the start of X-ray exposure. Reading stop means for stopping the reading of the charge data from each X-ray detection element until the frame at the end of the X-ray exposure, and each X of the frame at the start of the X-ray exposure and the next frame at the end of the X-ray exposure. An X-ray imaging apparatus comprising: a reconstructing unit that reconstructs an X-ray image by adding charge data read from the line detection element. 6. An X-ray imaging apparatus using an X-ray detector comprising a plurality of X-ray detection elements for accumulating detected X-rays as electric charges, comprising: Reading means for continuously reading frames as a period for sequentially reading the accumulated charges from all, and the reading from the frame at the start of X-ray exposure to the frame next to the frame at the end of X-ray exposure. First reconstructing means for reconstructing an X-ray image by adding charge data from each of the X-ray detecting elements read by the means for each of the X-ray detecting elements; Reading stop means for stopping the reading of the charge data from each X-ray detecting element by the reading means from the frame to the frame at the end of X-ray exposure, and the frame at the start of X-ray exposure and at the end of X-ray exposure. Of the next frame of The second reconstructing means for reconstructing an X-ray image by adding the charge data from the respective X-ray detecting elements read out by the outputting means, the first reconstructing means and the second reconstructing means. Selecting means for selecting either one is provided, and when the first reconstructing means is selected by the selecting means, the operations by the read stopping means and the second reconstructing means are stopped, and the first reconstructing means is operated by the selecting means. An X-ray imaging apparatus characterized in that when the second reconstruction unit is selected, the action of the first reconstruction unit is stopped.