JP6776610B2 - X-ray imaging system and X-ray imaging equipment - Google Patents

Description

The present invention relates to an X-ray imaging system and an X-ray imaging apparatus.

A so-called direct X-ray imaging device that generates a charge with a detection element according to the dose of the irradiated X-ray and converts it into an electric signal, and other wavelengths such as visible light with a scintillator or the like. A so-called indirect X-ray imaging device that converts the electromagnetic waves into electrical signals (that is, image data) by generating charges with a photoelectric conversion element such as a photodiode according to the energy of the converted and irradiated electromagnetic waves. Have been developed in various ways. In the present invention, the detection element in the direct type X-ray image capturing apparatus and the photoelectric conversion element in the indirect type X-ray imaging apparatus are collectively referred to as an X-ray detecting element.

This type of X-ray imaging apparatus is known as an FPD (Flat Panel Detector), and is conventionally configured as a so-called dedicated machine type (also referred to as a fixed type or the like) formed integrally with a support base or the like. However, in recent years, a portable (also referred to as a cassette type) X-ray imaging device in which an X-ray detection element or the like is housed in a housing and can be carried has been developed and put into practical use.

In such an X-ray imaging apparatus, for example, as shown in FIGS. 2 and 3 described later, a plurality of X-ray detection elements 7 are usually arranged in a two-dimensional shape (matrix shape), and each X-ray detection element is arranged. A switch element formed of a thin film transistor (hereinafter referred to as a TFT) 8 is connected to each of the 7's. Then, usually, X-ray imaging is performed by irradiating the X-ray imaging device with X-rays from the X-ray generator through a predetermined imaging site such as the front of the chest of the patient as the subject. ..

At that time, an off voltage is applied from the gate driver 15b of the scanning drive means 15 of the X-ray imaging apparatus to each line L1 to Lx of the scanning line 5 to turn off all TFTs 8 (that is, a charge accumulation state described later). By irradiating X-rays with), the electric charges generated in each X-ray detection element 7 by the irradiation of X-rays are accurately accumulated in each X-ray detection element 7 and an image is taken.

Therefore, for example, in a conventional dedicated machine-type X-ray image capturing device or the like, the X-ray imaging device is linked to each line L1 to Lx of the scanning line 5 by exchanging a signal with the X-ray generator. In many cases, the X-ray generator is configured to irradiate X-rays after confirming that an off-voltage is applied and the charge is accumulated.

However, for example, when the manufacturers of the X-ray imaging apparatus and the X-ray generator are different, it is often impossible to exchange signals between the two. Therefore, when the X-ray imaging device and the X-ray generator do not cooperate with each other in this way, the X-ray imaging device must detect that the X-ray is irradiated by itself. Therefore, in recent years, various X-ray imaging devices have been developed that are configured to detect the start of X-ray irradiation by themselves.

By the way, in recent years, it has been found that an X-ray imaging apparatus that detects the start of X-ray irradiation by itself may erroneously detect that X-rays have been irradiated even though the X-rays have not been irradiated. I came.

For example, when an impact or vibration is applied to an X-ray image capturing device, false detection may occur. Therefore, in Patent Document 1, X-ray imaging including a vibration detection unit that detects whether or not a signal exceeding a preset vibration allowable range is generated based on a change in a signal output from an X-ray detection element is taken. The device is described.

Further, in Patent Document 2, a dose of X-rays emitted from an X-ray generator is detected by an X-ray imaging apparatus before imaging, and the detected dose is less than a threshold value or the detected dose is determined. If it is equal to or greater than the threshold value but the arrival time to reach the threshold value exceeds a predetermined time, it is determined that the captured image is not a regular image and the wireless communication unit is controlled so as not to output the image to the control device. An X-ray imaging apparatus is described.

JP-A-2009-195612 Japanese Unexamined Patent Publication No. 2012-85794

By the way, for example, when a patient is photographed with an X-ray imaging device after an RI examination using a radioisotope is performed, the X-ray imaging device is emitted from the RI inside the patient's body. The γ-ray may erroneously detect that X-ray irradiation has started.

In this case, γ-rays are gradually emitted from the patient's body, so even if an X-ray imaging device is held near the patient, the signal read from the X-ray detection element of the X-ray imaging device can be obtained. It does not increase rapidly. Therefore, even if the method described in Patent Document 1 is applied in the above case, it is not possible to prevent erroneous detection by γ-rays emitted from RI in the patient's body.

Further, if the technique described in Patent Document 2 is applied when an erroneous detection occurs in the imaging of a patient after the RI examination, the image captured by the erroneous detection is not a regular image and can be controlled. It is prevented from being output to the device. However, since γ-rays are constantly emitted from patients after RI examination, in the technique described in Patent Document 2, the X-ray imaging apparatus erroneously detects the start of X-ray irradiation one after another by the γ-rays. It is not possible to stop the state where non-genuine images are continuously taken.

And, such a situation is not only in the imaging environment in which the patient is photographed after the RI examination as described above, but also in the imaging environment where the level of natural radiation is high, for example, in a hot spring area. Can occur.

However, when an erroneous detection occurs in this way, the X-ray image capturing apparatus subsequently performs the reading process of the image data d. In this case, the X-ray generator irradiates X-rays to capture the subject. It wasn't done, so in the end you'll only get an image with nothing taken. Therefore, an operator such as a radiologist will perform a copying loss process (that is, a process when imaging fails) and perform reimaging. For example, as described above, a patient after natural radiation or an RI examination. Due to the γ-rays emitted from the X-ray image capturing device, the X-ray imaging device makes false detections one after another, and when the copying loss processing is performed each time, the X-ray imaging device and the X-ray image capturing system using the X-ray imaging device It will be very inconvenient for operators such as radiologists.

The present invention has been made in view of the above problems, and an imaging environment in which the level of γ-rays and natural radiation is high when imaging is performed using an X-ray imaging apparatus that detects the start of X-ray irradiation by itself. It is an object of the present invention to provide an X-ray image taking system and an X-ray image taking device capable of accurately preventing an erroneous detection of the start of X-ray irradiation.

In order to solve the above problems, the X-ray imaging system of the present invention is used.
With multiple scan lines and multiple signal lines,
Multiple X-ray detectors arranged in two dimensions and
A switch that accumulates an electric charge in the X-ray detection element when an off voltage is applied through the scanning line, and discharges the electric charge accumulated in the X-ray detection element to the signal line when an on voltage is applied. With the element
A scanning drive means for switching the voltage applied to each scanning line between an on voltage and an off voltage.
A readout circuit that reads out the electric charge emitted from the X-ray detection element as image data, and
A detection means that performs detection processing to detect the start of X-ray irradiation based on the output of the X-ray sensor,
When the detection means detects the start of X-ray irradiation, the control means for turning off all the switch elements and shifting to a charge accumulation state for accumulating charges in each X-ray detection element.
X-ray imaging device equipped with
An X-ray generator that irradiates the X-ray imaging device with X-rays,
In a period other than the period in which the detection means is performing the detection process and the period in which the charge is accumulated, the imaging environment is set based on the output of the X-ray sensor of the X-ray imaging apparatus. It is provided with a determination means for determining whether or not the environment has a high level of radiation other than X-rays emitted from the X-ray generator.
The judgment unit may, photographing environment, if the level of radiation other than X-rays emitted from said X-ray generating apparatus is determined to be high environmental,
The X-ray image capturing apparatus is interrupted in the operation toward shooting .
The notification unit, by notifying prompts the user to do the sensitivity adjustment of the X-ray sensor of the users X-ray imaging apparatus and said Rukoto.

With multiple scan lines and multiple signal lines,
Multiple X-ray detectors arranged in two dimensions and
A switch that accumulates an electric charge in the X-ray detection element when an off voltage is applied through the scanning line, and discharges the electric charge accumulated in the X-ray detection element to the signal line when an on voltage is applied. With the element
A scanning drive means for switching the voltage applied to each scanning line between an on voltage and an off voltage.
A readout circuit that reads out the electric charge emitted from the X-ray detection element as image data, and
A detection means that performs detection processing to detect the start of X-ray irradiation based on the output of the X-ray sensor,
When the detection means detects the start of X-ray irradiation, the control means for turning off all the switch elements and shifting to a charge accumulation state for accumulating charges in each X-ray detection element.
The imaging environment is irradiated from the X-ray generator based on the output of the X-ray sensor in a period other than the period in which the detection means is performing the detection process and the period in which the charge is accumulated. It is equipped with a means for judging whether or not the environment has a high level of radiation other than X-rays.
The judgment unit may, if the photographing environment is determined to be the environment,
At least the detection means and the control means are interrupted in the operation toward shooting .
The notification means, user is informed that prompts the user to do the sensitivity adjustment of the X-ray sensor of X-ray imaging apparatus and said Rukoto.

According to the X-ray imaging apparatus of the method as in the present invention, when imaging is performed using the X-ray imaging apparatus that detects the start of X-ray irradiation by itself, in an imaging environment where the level of γ-rays and natural radiation is high. It is possible to accurately prevent the occurrence of erroneous detection of the start of X-ray irradiation.

It is a perspective view which shows the appearance of the X-ray image taking apparatus which concerns on this embodiment. It is sectional drawing which follows the XX line of FIG. It is a top view which shows the structure of a substrate. It is a block diagram which shows the equivalent circuit of the X-ray image taking apparatus. It is a figure which shows the example of the X-ray image taking apparatus when a plurality of X-ray sensors are provided. It is a figure which shows the example of the time transition (lower part) of the voltage value of the analog value of an X-ray sensor, and the pulse signal (upper part) which is output corresponding to it. (A) It is a figure explaining the mask time and the like, and (B) it is a figure explaining how to count the number of times a pulse signal P is output when the mask time is set. It is a figure which shows the configuration example which constructed the X-ray image photographing system which concerns on this embodiment in a photographing room or the like. It is a figure which shows the configuration example which was constructed so that the X-ray image taking system which concerns on this embodiment is mounted on a round-trip car. It is a figure which shows each process and period D performed by the control means of the X-ray image photographing apparatus at the time of photographing. It is a timing chart explaining the timing of applying an on-voltage to each scanning line of a radiation imaging apparatus when performing detection processing, charge accumulation state, and image data reading processing. It is a figure explaining that the state where a pulse signal is frequently output from an X-ray sensor and the start of X-ray irradiation may be erroneously detected in a photographing environment where the level of natural radiation is high. It is a figure which shows the display example on the display part of a console. It is a figure which shows the screen which is displayed when the sensitivity adjustment of an X-ray sensor is performed.

Hereinafter, embodiments of the X-ray imaging system and the X-ray imaging apparatus according to the present invention will be described with reference to the drawings.

In the following, the so-called indirect type X-ray imaging apparatus provided with a scintillator or the like as an X-ray imaging apparatus and converting emitted X-rays into electromagnetic waves of other wavelengths such as visible light to obtain an electric signal. As described above, the present invention can also be applied to a so-called direct type X-ray imaging apparatus in which X-rays are directly detected by a detection element without using a scintillator or the like.

[Configuration of X-ray imaging device]
First, the X-ray image capturing apparatus according to the present embodiment will be described. FIG. 1 is a perspective view showing the appearance of the X-ray imaging apparatus according to the present embodiment, and FIG. 2 is a cross-sectional view taken along the line XX of FIG. In the following, the vertical direction of the X-ray image capturing device 1 will be described based on the case where the X-ray image capturing device 1 is arranged in the state of FIG.

As shown in FIG. 1, a power switch 37, a changeover switch 38, a connector 39, an indicator 40, and the like are arranged on one side surface of the housing 2 of the X-ray image capturing apparatus 1. Further, although not shown, an antenna 41 (see FIG. 4 to be described later) for wirelessly communicating with the outside is provided on the opposite side surface of the housing 2.

As shown in FIG. 2, a base 31 is arranged inside the housing 2, and a substrate 4 is arranged on the upper surface side of the base 31 via a thin lead plate (not shown) or the like. .. The above-mentioned X-ray detection element 7 and the like are provided on the upper surface of the substrate 4, and this point will be described later. The scintillator 3 and the scintillator substrate 34 are arranged above the substrate 4 so that the scintillator 3 formed on the scintillator substrate 34 and the X-ray detection element 7 of the substrate 4 face each other.

On the lower surface side of the base 31, a PCB board 33 on which electronic components 32 and the like are arranged, a built-in power supply 24, and the like are attached. An X-ray sensor 25 is attached to the lower surface side of the base 31. In this embodiment, the sensor panel SP is formed in this way. Further, in the present embodiment, a cushioning material 35 is provided between the sensor panel SP and the side surface of the housing 2 to prevent them from colliding with each other.

As shown in FIG. 3, on the upper surface (that is, the surface facing the scintillator 3) 4a of the substrate 4, the plurality of scanning lines 5 and the plurality of signal lines 6 are arranged so as to intersect each other. Further, an X-ray detection element 7 is provided in each region r partitioned by the plurality of scanning lines 5 and the plurality of signal lines 6. In this embodiment, the X-ray detection elements 7 are arranged in a two-dimensional shape (matrix shape) in this way.

Further, in the present embodiment, a plurality of bias lines 9 are arranged in parallel with each signal line 6, and each bias line 9 is connected to the connection 10. A plurality of input / output terminals 11 are provided on the peripheral edge of the substrate 4, and each input / output terminal 11 is connected to each scanning line 5, each signal line 6, and connection 10. Although not shown, each input / output terminal 11 is connected to a flexible circuit board in which a chip such as a readout IC 16 described later is incorporated on the film, and the flexible circuit board is routed to the back surface side of the substrate 4. It is designed to be connected to the PCB board 33 and the like described above.

Here, the circuit configuration of the X-ray image capturing apparatus 1 will be described. FIG. 4 is a block diagram showing an equivalent circuit of the X-ray imaging apparatus 1 according to the present embodiment. In each X-ray detection element 7, electric charges corresponding to the dose of X-rays emitted through a subject (not shown) (or the amount of electromagnetic waves converted by the scintillator 3) are generated in each X-ray detection element 7. It has become. Although the case where the X-ray detection element 7 is composed of a photodiode will be described below, it is also possible to use, for example, a phototransistor, a CCD (Charge Coupled Device), or the like as the X-ray detection element 7.

A bias wire 9 is connected to one electrode 7a of each X-ray detection element 7, and a reverse bias voltage is applied from the bias power supply 14 to each X-ray detection element 7 via the bias wire 9 and the connection 10. It is supposed to be done. Further, a TFT 8 is connected as a switch element to the other electrode 7b of each X-ray detection element 7, and the TFT 8 is connected to a signal line 6.

Further, the TFT 8 is turned on when an on-voltage is applied from the scanning driving means 15 described later via the scanning line 5, and the electric charge accumulated in the X-ray detection element 7 is discharged to the signal line 6. Further, when an off voltage is applied via the scanning line 5, the off state is set, the emission of electric charge from the X-ray detection element 7 to the signal line 6 is stopped, and the electric charge is accumulated in the X-ray detection element 7. It has become.

Each scanning line 5 is connected to the gate driver 15b of the scanning driving means 15. In the scanning drive means 15, on voltage and off voltage are supplied from the power supply circuit 15a to the gate driver 15b via the wiring 15c, and the gate driver 15b applies the voltage to each line L1 to Lx of the scanning line 5. The voltage is switched between on-voltage and off-voltage.

Further, each signal line 6 is connected to each read circuit 17 built in the read IC 16. In the present embodiment, the reading circuit 17 is composed of an integrating circuit 18 and a correlated double sampling circuit 19 and the like. An analog multiplexer 21 and an A / D converter 20 are further provided in the readout IC 16. In FIG. 4, the correlated double sampling circuit 19 is referred to as CDS.

When the X-ray image capturing device 1 is irradiated with X-rays from an X-ray irradiating device (not shown) with each TFT 8 as a switch element turned off at the time of photographing, each X-ray detecting element 7 is irradiated with X-rays. The charge generated in the X-ray detection element 7 is accumulated in the X-ray detection element 7. Then, when the image data d is read out from each X-ray detection element 7, an on-voltage is sequentially applied from the gate driver 15b of the scanning driving means 15 to each of the lines L1 to Lx of the scanning line 5, and each X is sequentially applied. Charges are emitted from the inside of the line detection element 7 to the signal line 6, respectively.

Then, the electric charge flows into the integrating circuit 18 of each reading circuit 17 and is accumulated, and a voltage value corresponding to the accumulated electric charge amount is output. The correlation double sampling circuit 19 outputs the difference between the output values output from the integrating circuit 18 before and after the electric charge flows from each X-ray detection element 7 as analog image data d.

Then, each output image data d is sequentially transmitted to the A / D converter 20 via the analog multiplexer 21, and is sequentially converted into digital value image data d by the A / D converter 20 and stored in the storage means 23. It is output and saved sequentially. In this way, the image data d is read out.

The control means 22 is a computer in which a CPU (Central Processing Unit), a ROM (Read Only Memory), a RAM (Random Access Memory), an input / output interface, or the like (not shown) is connected to a bus, an FPGA (Field Programmable Gate Array), or the like. It is configured. It may be composed of a dedicated control circuit.

The control means 22 includes a storage means 23 composed of SDRAM (Static RAM), SDRAM (Synchronous DRAM), NAND flash memory, etc., a built-in power supply 24 composed of a lithium ion capacitor, etc., an X-ray sensor 25, and the like. It is connected. Further, the control means 22 is connected to a communication unit 42 for communicating with the outside by a wireless system or a wired system via the antenna 41 and the connector 39 described above.

In addition, for example, in order to shield the wiring so that noise is not picked up by the wiring connecting the X-ray sensor 25 and the control means 22, or to make it easy for X-rays to reach the X-ray sensor 25, the base 31 A process such as not providing a thin lead plate on the portion corresponding to the X-ray sensor 25 (see FIG. 2) is appropriately performed.

Further, in FIGS. 2 and 4, only one X-ray sensor 25 is provided in the X-ray image capturing apparatus 1, but it is also possible to provide a plurality of X-ray sensors 25 as shown in FIG. 5, for example. That is, the X-ray sensor 25 can be configured to be arranged not only at the central position on the lower surface side of the base 31, but also at a position other than the central position. Although FIG. 5 shows a case where two X-ray sensors 25 are provided, three or more X-ray sensors 25 may be provided. With this configuration, even when the X-ray is applied to the X-ray imaging apparatus 1 with the irradiation field narrowed down, the X-ray can be detected by any one of the plurality of X-ray sensors 25. It will be possible.

On the other hand, in the present embodiment, the control means 22 functions as a detection means that performs a detection process for detecting the start of X-ray irradiation based on the output of the X-ray sensor 25. It is also possible to configure the detection means as a circuit or the like separate from the control means 22.

In the present embodiment, as shown in FIG. 6, in the X-ray sensor 25, when the voltage value Va of the analog value generated when the X-ray is irradiated fluctuates and the voltage value Va exceeds the positive set value Vth +. The pulse signal P is output when the value falls below the negative set value Vth−. Then, when the X-rays emitted from the X-ray generator described later are incident on the X-ray sensor 25, one photon of the X-rays is attached to the X-ray sensor 25, for example, as shown by B and C in FIG. One pulse signal P is output each time photon) is incident.

However, when radiation such as natural radiation having a large energy is incident on the X-ray sensor 25, the generated voltage value Va undulates greatly, and even though one photon is incident on the X-ray sensor 25, for example, A in FIG. As shown by, the pulse signal P may be output a plurality of times. Therefore, in the present embodiment, as shown in FIG. 7A, when the pulse signal P is output from the X-ray sensor 25, the control means 22 has a predetermined mask time after the pulse signal P is output. Until Δtm elapses, it is not determined at least whether or not the pulse signal P is output from the X-ray sensor 25.

Then, in the present embodiment, as shown in FIG. 7B, for example, the control means 22 as the detection means receives a predetermined number of times N (within a predetermined time ΔT after the pulse signal P is output from the X-ray sensor 25. When the pulse signal P (three times in FIG. 7B) is output, it is determined that the X-ray irradiation from the X-ray generator has started.

In the present embodiment, for example, when the predetermined number of times N is set to 3 times as described above, the control means 22 performs the third pulse signal P as shown in FIG. 7 (B). Is output, it is determined that the X-ray irradiation has started (even if the predetermined time ΔT has not elapsed), and the start of the X-ray irradiation is detected.

[Configuration of X-ray imaging system]
Next, the X-ray image capturing system according to the present embodiment will be described. The X-ray image capturing system 50 can be constructed, for example, in the photographing room Ra or the like as shown in FIG. 8, or can be constructed so as to be mounted on the round-trip vehicle 70 as shown in FIG. ..

For example, when the X-ray image photographing system 50 is constructed in the photographing room Ra or the like as shown in FIG. 8, the X-ray image photographing device 1 is loaded into the cassette holder 51a of the photographing table 51 and the photographing is performed. In FIG. 8, the photographing table 51A represents a photographing table for standing position photographing, and the photographing table 51B represents a photographing table for lying position photographing. Further, for example, it is also possible to perform imaging by inserting the X-ray image capturing apparatus 1 between a subject (not shown) lying down on the top plate of the imaging table 51B for recumbent imaging and the top plate.

The imaging room Ra is provided with at least one X-ray generator 52 that irradiates the X-ray image capturing apparatus 1 with X-rays through a subject (not shown). Further, the photographing room Ra is provided with an access point 53 for relaying wireless or wired communication between the X-ray image capturing device 1 in the photographing room Ra and the console 58 or the like in the front room Rb. A repeater 54 is provided. The communication between the X-ray image capturing device 1 and the repeater 54 may be performed by a wireless method or a wired method.

Further, in the generator 55 of the X-ray generator 52, when the tube voltage, tube current, irradiation time, irradiation dose, etc. are set by an operator such as a radiologist, the tube voltage set from the X-ray generator 52 is set. Various controls are performed on the X-ray generator 52, such as irradiating the X-ray with a dose corresponding to the above.

The front chamber (also referred to as an operation room or the like) Rb is provided with an operation console 57 of the X-ray generator 52, and the operation console 57 is operated by an operator such as a radiologist with respect to the generator 55. An exposure switch 56 for instructing the start of X-ray irradiation and the like is provided. Further, in the anterior chamber Rb, a console 58 composed of a computer or the like is installed. It is also possible to configure the console 58 so as to be provided outside the photographing room Ra or the anterior room Rb, a separate room, or the like.

A display unit 58a composed of a CRT (Cathode Ray Tube), an LCD (Liquid Crystal Display), or the like, and an input means 58b such as a mouse, keyboard, or touch panel are connected to the console 58. Further, a storage means 58c composed of an HDD (Hard Disk Drive) or the like is connected to or built in the console 58.

On the other hand, as shown in FIG. 9, it is also possible to bring the round-trip car 70 equipped with the X-ray generator 52, the console 58, etc. to the hospital room R1 (or the operating room or the emergency treatment room) to take an image. In this case, the generator 55, the repeater 54 (both not shown) and the like are housed in the main body of the round-trip vehicle 70.

Then, in this case, the X-ray image capturing apparatus 1 is used for photographing so as to be inserted between the bed Be and the patient who is the subject H as shown in FIG. 9 or to be applied to the patient's body. .. In this case as well, the operator T, such as a radiologist, operates the exposure switch 56 to irradiate X-rays from the X-ray generator 52 and perform imaging.

[Processing by judgment means]
Next, the processing by the determination means in the X-ray image capturing system 50 according to the present embodiment will be described.

In the following, a case where the control means 22 of the X-ray image capturing apparatus 1 is configured to function as a determination means will be described. For example, a console 58 or a computer separate from the console 58 is used as the determination means. It can also be configured to work. Then, in that case, it is configured to exchange necessary information and signals between the X-ray image capturing apparatus 1 and the determination means.

Further, in the following, when the control means 22 of the X-ray image capturing apparatus 1 functions as a determination means, it will be described as the determination means 22. In addition, the operations of the X-ray image capturing system 50 and the X-ray image capturing device 1 according to the present embodiment will also be described.

In the present embodiment, the determination means 22 outputs the X-ray sensor 25 in a period other than the period in which the above-mentioned X-ray irradiation start detection process is performed and the subsequent period in which the charge is accumulated. Based on the above, the imaging environment is an environment in which the level of radiation other than X-rays emitted from the X-ray generator 52 (that is, the above-mentioned natural radiation, γ-rays emitted from the patient's body after RI examination, etc.) is high. Determine if it exists. Then, when it is determined that the imaging environment is an environment in which the level of radiation other than X-rays is high, the X-ray image capturing apparatus 1 is adapted to interrupt the operation performed for imaging. Hereinafter, a specific description will be given.

At the time of imaging, as shown in FIG. 10, when the control means 22 of the X-ray image capturing apparatus 1 receives an awakening signal from, for example, the console 58 in the standby state, the control means 22 of the scanning driving means 15 (see FIG. 4) gates. Reset of the X-ray detection element 7 by sequentially applying an on-voltage from the driver 15b to each of the lines L1 to Lx of the scanning line 5 to remove the electric charge remaining in each X-ray detection element 7 from each X-ray detection element 7. Let the process be performed. Note that D in FIG. 10 will be described later.

Then, for example, when the reset process of the X-ray detection element 7 is performed for a predetermined frame or for a predetermined time, the control means 22 (in this case, the control means 22 as the detection means) is based on the output of the X-ray sensor 25 as described above. The detection process for detecting the start of X-ray irradiation is started.

If the detection process is performed with the TFT 8 which is a switch element turned off, the dark charge (also referred to as dark current) generated in the X-ray detection element 7 is accumulated in the X-ray detection element 7. In the present embodiment, as shown in FIG. 11, the control means 22 sequentially applies an on-voltage to each of the lines L1 to Lx of the scanning line 5 to reset the X-ray detection element 7 while performing the detection process. It is designed to let you.

Then, when the control means 22 detects the start of X-ray irradiation as described above, as shown in FIG. 11, the control means 22 stops the reset process of the X-ray detection element 7, and each line of the scanning line 5 from the gate driver 15b. An off voltage is applied to L1 to Lx to turn off all TFTs 8, and the electric charge generated in each X-ray detection element 7 by X-ray irradiation is accumulated in each X-ray detection element 7. Migrate. After that, an on-voltage is sequentially applied to each of the lines L1 to Lx of the scanning line 5 to perform the above-mentioned image data d reading process.

Then, when the image data d is read, the control means 22 transfers the read image data d, preview data extracted from the image data d, and the like to the console 58, and detects X-rays, as shown in FIG. Reset processing of the element 7 and the like are performed.

Further, since the offset portion due to the dark charge described above is superimposed on the read image data d, after the reading process of the image data d and the reset process of the X-ray detection element 7 shown in FIG. In some cases, the sequence shown in FIG. 11 is repeated in a state where the X-ray image capturing apparatus 1 is not irradiated with X-rays, and a process of reading the above offset portion (also referred to as a dark image or the like) is performed instead of the image data d. is there.

Then, when the control means 22 finishes those processes, it shifts to the standby state again. Further, when the next shooting is specified, the reset process of the X-ray detection element 7 may be started immediately for the next shooting without shifting to the standby state.

On the other hand, in a normal case, the pulse signal P is hardly output from the X-ray sensor 25 of the X-ray imaging apparatus 1 unless the X-ray generator 52 (see FIGS. 8 and 9) emits X-rays. Alternatively, even if the pulse signal P is output, its frequency is very low. However, as described above, for example, the X-ray imaging apparatus 1 is used for imaging in an imaging environment such as a hot spring area where the level of natural radiation is high, or the X-ray imaging apparatus 1 is used to perform an RI examination on a patient. In an imaging environment where imaging is performed, the X-ray sensor 25 may frequently output a pulse signal P, for example, as shown in FIG.

Then, in such a shooting environment, when the detection process of the start of X-ray irradiation is performed in a state where the pulse signal P is frequently output from the X-ray sensor 25, the X-ray generator 52 does not irradiate X-rays. Nevertheless, after the pulse signal P is output from the X-ray sensor 25, the pulse signal P is output a predetermined number of times N within a predetermined time ΔT, and the control means 22 as a detection means is irradiated with X-rays. There is a possibility that it will be falsely detected as started.

Then, even if the state shifts to the charge accumulation state (see FIG. 11) in that state, in this case, the X-ray generator 52 does not irradiate the X-ray and the image is taken. Only dark charges are accumulated in the X-ray detection element 7, and in the end, only an unphotographed image can be obtained. Then, if nothing is photographed in the image, an operator such as a radiologist has to perform a process of performing a copying loss process and performing a re-imaging process, but then the X-ray image capturing device 1 or the X-ray image As described above, the photographing system 50 becomes very inconvenient for the operator.

Therefore, in the present embodiment, the determination means 22 has a period (that is, X-ray) other than the period during which the detection process for the start of X-ray irradiation is being performed and the period during which the charge is accumulated (that is, the period indicated by D in FIG. 10). During the period when it is clear that X-rays are not emitted from the generator 52), the imaging environment is based on the output of the X-ray sensor 25, and the imaging environment is radiation other than X-rays emitted from the X-ray generator 52 (that is, the above-mentioned It has come to judge whether or not the environment has a high level of natural radiation (γ-rays emitted from the patient's body after RI examination, etc.).

Specifically, the determination means 22 is in a period in which the X-ray detection element 7 is reset before the period D, or in a period after the image data d is read out after the period D. For example, the process of counting the number of pulse signals P output from the X-ray sensor 25 within a preset time τ (for example, 1 second) is repeated. Then, when the number n of pulse signals P equal to or greater than the preset threshold value nth is output within the above time τ, the level of radiation other than the X-rays emitted from the X-ray generator 52 is set in the imaging environment. It can be configured to determine that the environment is high.

The determination process in the determination means 22 can be configured as described above, but in addition, for example, the time interval is measured and measured each time the pulse signal P is output from the X-ray sensor 25. It is also possible to configure the judgment based on the time interval (in this case, the shorter the time interval, the higher the radiation level), and the judgment method is not limited to a predetermined method.

Then, in the present embodiment, when the determination means 22 determines that the imaging environment is an environment in which the level of radiation other than the X-rays emitted from the X-ray generator 52 is high as described above, The operation of the X-ray image capturing device 1 for photographing is interrupted.

That is, when the determination means 22 determines as described above during the period during which the reset processing of the X-ray detection element 7 is performed before the period D shown in FIG. 10, the X-ray image capturing apparatus 1 performs the determination. The reset process of the X-ray detection element 7 being performed at the present time is interrupted (if a process other than the reset process is performed, the process is also interrupted), and the subsequent process is not performed.

Further, when the determination means 22 determines as described above in the period after the reading process of the image data d after being shown in FIG. 10, the X-ray image capturing apparatus 1 is performing the image data at that time. The read-out process of d, the transfer process of image data d and the like, the reset process of the X-ray detection element 7, and the read-out process of the offset due to the dark charge described above are interrupted.

Further, when the determination means 22 determines as described above in the period after the image data d reading process shown in FIG. 10, the image data d reading process, the image data d transfer process, and the X-ray are performed. After completing the reset process of the detection element 7 or the process of reading out the offset due to the dark charge described above, the operation is interrupted when the standby state is reached, and the operation for the next shooting is restarted. It may be configured so as not to cause.

As described above, in the present embodiment, the determination means 22 is irradiated with X-rays from the X-ray generator 52 during the period other than the period during which the detection process of the start of X-ray irradiation is being performed and the period D of the charge accumulation state D. During the period when it is clear that the X-ray sensor 25 does not, the state of the pulse signal P output from the X-ray sensor 25 is monitored, and the imaging environment is an environment in which the level of radiation other than X-rays emitted from the X-ray generator 52 is high. Judge whether or not.

If the pulse signal P is frequently output from the X-ray sensor 25 during the period when it is clear that the X-ray generator 52 is not irradiating X-rays, the imaging environment is natural radiation or γ. It is possible to accurately judge that the environment has a high level of lines and the like.

Then, when it is determined that the photographing environment is an environment having a high level of natural radiation, γ-rays, etc., the operation of the X-ray image capturing apparatus 1 for photographing is interrupted. , The detection means (control means 22) of the X-ray imaging apparatus 1 performs the detection process of the start of X-ray irradiation in a state where the level of natural radiation or γ-ray is high, and the patient after the natural radiation or RI examination. Accurately prevent the start of X-ray irradiation from being erroneously detected by γ-rays emitted from the body.

[effect]
As described above, according to the X-ray image taking system 50 and the X-ray image taking device 1 according to the present embodiment, the device itself takes an image using the X-ray image taking device 1 that detects the start of X-ray irradiation. At this time, the determination means 22 monitors the state of the pulse signal P output from the X-ray sensor 25 during a period when it is clear that the X-ray generator 52 is not irradiating X-rays, and the imaging environment is changed to X. It is determined whether or not the environment has a high level of radiation other than X-rays emitted from the ray generator 52, that is, a level of natural radiation and a level of γ-rays emitted from the patient's body after an RI examination.

Therefore, if the pulse signal P is frequently output from the X-ray sensor 25 during the period when it is clear that the X-ray generator 52 is not irradiating X-rays, the imaging environment is natural radiation or γ. It is possible to accurately judge that the environment has a high level of lines and the like.

Then, in the X-ray image capturing system 50 and the X-ray image capturing apparatus 1 according to the present embodiment, when it is determined that the photographing environment is an environment having a high level of natural radiation, γ-rays, or the like, X-ray image photographing is performed. Since the imaging performed by the device 1 and the operation performed for the next imaging are interrupted, it is possible to accurately prevent the occurrence of erroneous detection of the start of X-ray irradiation.

Therefore, in an imaging environment where the level of natural radiation or γ-rays is high, the X-ray imaging apparatus 1 repeatedly erroneously detects the start of X-ray irradiation, and an operator such as a radiologist performs a copying loss process each time. Since such a situation does not occur, the X-ray image capturing system 50 and the X-ray image capturing device 1 according to the present embodiment are very easy to use for an operator such as a radiologist.

In the above embodiment, the period D shown in FIG. 10, that is, the period during which the detection process of the start of X-ray irradiation is being performed and the period during the charge accumulation state (that is, the X-ray is irradiated from the X-ray generator 52). During the (possible period), the imaging environment is an environment in which the level of radiation other than X-rays emitted from the X-ray generator 52 is high, based on the above judgment process, that is, the output of the X-ray sensor 25. It is possible to perform a process of determining whether or not, and it is also possible to configure so that the determination process is not performed during the period D.

[Notification to users]
As described above, in the X-ray imaging system 50 and the X-ray imaging apparatus 1 according to the present embodiment, the imaging environment is the level of radiation other than X-rays emitted from the X-ray generator 52, that is, natural radiation. When it is determined that the environment is such that the level and the level of γ-rays emitted from the patient's body after the RI examination are high, the X-ray imaging apparatus 1 interrupts the next imaging or the operation for the next imaging. To do. Therefore, the user may not notice that the operation of the X-ray image capturing apparatus 1 is interrupted unless the user such as a radiologist is notified.

Therefore, in the X-ray image capturing system 50 according to the present embodiment, as described above, the determination means 22 notifies the X-ray image capturing device 1 when the operation of the X-ray image capturing device 1 is interrupted. It can be configured to notify that radiation other than X-rays emitted from the X-ray generator 52 has been detected.

For example, the display unit 58a of the console 58 is used as the notification means, and as shown in FIG. 13, for example, a display E1 such as "Radiation was detected during preparation for shooting" is displayed on the display unit 58a to notify the user. It can be configured to do so. A notification means may be provided as a display device separate from the display unit 58a of the console 58. It is also possible to configure the notification means to notify by voice, light emission (including blinking, etc.) or a combination thereof instead of displaying.

Then, by notifying that the radiation other than the X-rays emitted from the X-ray generator 52 is detected in this way, the radiologist knows that the X-ray imaging device 1 is interrupting the operation because the radiation is detected. It is possible to notify the user such as, etc., and to urge the user to take appropriate measures (including cancellation of shooting, etc.).

[Adjustment of X-ray sensor sensitivity]
In addition, the notification means can be configured to perform notification as described above and to encourage a user such as a radiologist to adjust the sensitivity of the X-ray sensor 25 of the X-ray image capturing device 1. .. For example, as shown in FIG. 13, it is possible to display E2 such as "Please adjust the sensitivity before taking a picture" on the display unit 58a of the console 58 to notify the user. Is.

In this case as well, it is possible to configure the notification by voice, light emission (including blinking, etc.), or a combination thereof instead of the display. In addition, for example, by displaying a display such as "after adjusting the sensitivity" in a color or display method different from the display color or display method of other parts, the user such as a radiologist is notified in an easy-to-understand manner. It is also possible to configure it to do so.

Then, in this case, when a user such as a radiologist clicks the "OK" button icon F, the display is switched as shown in FIG. 14, for example, and the type of sensitivity on the right side of the screen (low sensitivity, medium sensitivity, high sensitivity, high sensitivity) It is possible to adjust the sensitivity by clicking and selecting the button icon G having a predetermined sensitivity from the button icons G1 to G4 of +). Then, in this case, for example, the user adjusts the sensitivity of the X-ray sensor 25 and clicks the "restart" button icon G5 to release the interruption, and the X-ray image capturing device 1 operates for shooting. To resume.

On the other hand, for example, when the determination means 22 interrupts the operation of the X-ray image capturing device 1 for photographing as described above, the sensitivity of the X-ray sensor 25 of the X-ray image capturing device 1 is adjusted. It is also possible to provide a sensitivity adjusting means that automatically (that is, without the choice of a user such as a radiologist). In this case, for example, the control means 22 of the console 58 or the X-ray image capturing device 1 can be configured to function as the sensitivity adjusting means, and the sensitivity adjusting means can be provided as a device separate from them. It is also possible to provide it.

As described above, in the present embodiment, as shown in FIG. 6, the X-ray sensor 25 is set with a positive set value Vth + or a negative set value Vth− with respect to the fluctuating analog value voltage value Va. Has been done. Then, when the absolute values such as these set values Vth + are set smaller (that is, when the absolute values are set to be closer to 0), even if the generated voltage value Va fluctuates slightly, the set values Vth + etc. Therefore, the sensitivity of the X-ray sensor 25 is set to high sensitivity. On the contrary, if the absolute value such as the set value Vth + is set larger, the generated voltage value Va fluctuates greatly. However, since the set value Vth + and the like are exceeded, the sensitivity of the X-ray sensor 25 is set to low sensitivity.

Then, when the X-ray sensor 25 outputs the pulse signal P by natural radiation, γ-rays emitted from the patient's body after the RI examination, or the like with the current sensitivity, the X-ray sensor 25 The sensitivity is adjusted in the direction of lowering the sensitivity (the direction in which the absolute value such as the set value Vth + becomes larger).

Therefore, for example, as in the example shown in FIG. 13, when the sensitivity of the X-ray sensor 25 is set to "high sensitivity +" (representing a higher sensitivity than the high sensitivity), the X-ray sensor 25 The sensitivity is selected and adjusted from the direction of lowering the sensitivity, that is, from "low sensitivity" G1, "medium sensitivity" G2, and "high sensitivity" G3.

Then, by appropriately adjusting the sensitivity of the X-ray sensor 25 in this way, the X-ray sensor 25 emits radiation other than X-rays emitted from the X-ray generator 52, that is, natural radiation or after RI inspection. It is possible to further reduce the possibility of outputting a pulse signal P in response to γ-rays or the like emitted from the body of a patient, and as in the present embodiment, the output of the X-ray sensor 25 (pulse in the present embodiment). When performing detection processing to detect the start of X-ray irradiation based on signal P), it is possible to accurately detect the possibility of false detection due to natural radiation or γ-rays emitted from the patient's body after RI examination. It is possible to reduce it.

[About the configuration example when the judgment process is performed during the period D]
On the other hand, in the above embodiment, the determination means 22 has a period other than the period during which the detection process of the start of X-ray irradiation is being performed and the period D (see FIG. 10) of the charge accumulation state (that is, X-ray generators 52 to X). When performing a judgment process for determining whether or not the imaging environment is an environment in which the level of radiation other than the X-rays emitted from the X-ray generator 52 is high during the period (when it is clear that the rays are not irradiated). Explained. Then, in that case, the above-mentioned determination process may not be performed during the above-mentioned period D, or the above-mentioned determination process may be performed.

When the determination process is configured to be performed during the period D as well, the determination means 22 is used in an environment where the imaging environment is a high level of radiation other than the X-rays emitted from the X-ray generator 52 during the period D. When it is determined that there is, the X-ray image capturing device 1 can be configured to interrupt the operation of the X-ray image capturing device 1 in the same manner as described above.

However, if it is determined that the imaging environment is an environment in which the level of radiation other than the X-rays emitted from the X-ray generator 52 is high during the period of detecting the start of X-ray irradiation. However, if the X-ray generator 52 properly irradiates X-rays while the charge accumulation state continues, there is a high possibility that the subject will be properly photographed in the captured image, and the shooting is successful. There is a high possibility that

Then, even though the subject is properly photographed in the photographed image, the determination means 22 is an environment in which the photographing environment is an environment in which the level of radiation other than the X-rays emitted from the X-ray generator 52 is high. As a result, the X-ray image capturing device 1 interrupts the operation being performed for imaging, or the notification means detects radiation other than the X-ray emitted from the X-ray generator. If it is configured to notify what has been done (see FIG. 13), it becomes annoying for users such as radiologists.

That is, even if the imaging environment is an environment in which the level of radiation other than the X-rays emitted from the X-ray generator 52 is high, if the subject is properly photographed in the captured image, the radiologist Etc. may think that it is better for the X-ray image capturing device 1 to continue the operation performed toward the imaging, and also to emit radiation other than the X-ray emitted from the X-ray generator. In some cases, we do not want you to be notified of the detection.

Therefore, when the determination process is configured to be performed during the above period D as described above, the determination means 22 is an environment in which the imaging environment has a high level of radiation other than the X-rays emitted from the X-ray generator 52. Even if it is determined that the X-ray is properly emitted from the X-ray generator 52 based on the output of the X-ray sensor 25 during the charge accumulation state (that is, the charge accumulation state). In the case where the frequency at which the pulse signal P is output from the X-ray sensor 25 increases and then decreases and returns to the original frequency), the X-ray image capturing device 1 is used for imaging. It is possible to configure it so that the current operation is continued, and it is also possible to configure the notifying means not to notify that it has detected radiation other than X-rays emitted from the X-ray generator 52. is there.

With this configuration, even if the shooting environment is an environment in which the level of radiation other than the X-rays emitted from the X-ray generator 52 is high, the subject is properly shot in the shot image. In addition, the X-ray image capturing device 1 continues the operation of the X-ray imaging device 1 and does not notify each time that a radiation other than the X-ray emitted from the X-ray generator is detected. It is possible to accurately prevent the user from feeling the above-mentioned annoyance.

The X-ray sensor 25 is not limited to the above-mentioned method of detecting X-rays and outputting them as a pulse signal, but may also be a method of extracting as a continuous output signal by integrating a charge signal generated by the X-rays. Good.

Further, it goes without saying that the present invention is not limited to the above-described embodiments and the like, and can be appropriately modified as long as the gist of the present invention is not deviated.

1 X-ray imaging device 5 Scanning line 6 Signal line 7 X-ray detection element 8 TFT (switch element)
15 Scanning drive means 17 Read circuit 22 Control means (detection means, control means, determination means, sensitivity adjusting means)
25 X-ray sensor 50 X-ray imaging system 52 X-ray generator 58 console (judgment means, sensitivity adjustment means)
58a Display unit (notification means)
Period D (the period obtained by combining the period during which the detection means is performing the detection process and the period during which the charge is accumulated)
d Image data P Pulse signal (X-ray sensor output)
Va voltage value Vth +, Vth- set value

Claims (9)

With multiple scan lines and multiple signal lines,
Multiple X-ray detectors arranged in two dimensions and
A switch that accumulates an electric charge in the X-ray detection element when an off voltage is applied through the scanning line, and discharges the electric charge accumulated in the X-ray detection element to the signal line when an on voltage is applied. With the element
A scanning drive means for switching the voltage applied to each scanning line between an on voltage and an off voltage.
A readout circuit that reads out the electric charge emitted from the X-ray detection element as image data, and
A detection means that performs detection processing to detect the start of X-ray irradiation based on the output of the X-ray sensor,
When the detection means detects the start of X-ray irradiation, the control means for turning off all the switch elements and shifting to a charge accumulation state for accumulating charges in each X-ray detection element.
X-ray imaging device equipped with
An X-ray generator that irradiates the X-ray imaging device with X-rays,
In a period other than the period in which the detection means is performing the detection process and the period in which the charge is accumulated, the imaging environment is set based on the output of the X-ray sensor of the X-ray imaging apparatus. It is provided with a determination means for determining whether or not the environment has a high level of radiation other than X-rays emitted from the X-ray generator.
The judgment unit may, photographing environment, if the level of radiation other than X-rays emitted from said X-ray generating apparatus is determined to be high environmental,
The X-ray image capturing apparatus is interrupted in the operation toward shooting .
Notifying means, the X-ray imaging system according to claim Rukoto to controller generates a notice of a request to make sensitivity adjustment of the X-ray sensor of the users X-ray imaging apparatus. When the determination means interrupts the operation of the X-ray imaging apparatus for imaging, the notification means is notified that radiation other than the X-rays emitted from the X-ray generator is detected. The X-ray imaging system according to claim 1, wherein the X-ray imaging system is used. The X-ray image capturing apparatus is provided with a sensitivity adjusting means for automatically adjusting the sensitivity of the X-ray sensor of the X-ray imaging apparatus when the determination means interrupts the operation of the X-ray imaging apparatus toward imaging. The X-ray imaging system according to claim 1 or 2 , wherein the X-ray imaging system is characterized. The determination means takes an image based on the output of the X-ray sensor of the X-ray image capturing apparatus even during a period in which the detection means is performing the detection process and the period in which the charge is accumulated. The invention according to any one of claims 1 to 3 , wherein it is determined whether or not the environment is an environment in which the level of radiation other than the X-rays emitted from the X-ray generator is high. X-ray imaging system. Even when the imaging environment determines that the radiography environment is an environment in which the level of radiation other than the X-rays emitted from the X-ray generator is high, the X-rays are emitted during the charge accumulation state. When it is determined that X-rays are appropriately emitted from the X-ray generator based on the output of the X-ray sensor of the image capturing device, the operation of the X-ray imaging device for photographing is performed. The X-ray imaging system according to claim 4 , wherein the X-ray imaging system is continued. Even when the imaging environment determines that the level of radiation other than the X-rays emitted from the X-ray generator is high, the determination means still receives the X-rays during the charge accumulation state. When it is determined that X-rays are appropriately emitted from the X-ray generator based on the output of the X-ray sensor of the image capturing apparatus, the notification means is other than the X-rays emitted from the X-ray generator. claim 4 or X-ray imaging system according to claim 5, characterized in that it is the radiation is informed that it has detected. Any of claims 1 to 6 , wherein the X-ray sensor is configured to output a pulse signal when a voltage value generated by X-ray irradiation exceeds a predetermined set value. The X-ray imaging system according to item 1. With multiple scan lines and multiple signal lines,
Multiple X-ray detectors arranged in two dimensions and
A switch that accumulates an electric charge in the X-ray detection element when an off voltage is applied through the scanning line, and discharges the electric charge accumulated in the X-ray detection element to the signal line when an on voltage is applied. With the element
A scanning drive means for switching the voltage applied to each scanning line between an on voltage and an off voltage.
A readout circuit that reads out the electric charge emitted from the X-ray detection element as image data, and
A detection means that performs detection processing to detect the start of X-ray irradiation based on the output of the X-ray sensor,
When the detection means detects the start of X-ray irradiation, the control means for turning off all the switch elements and shifting to a charge accumulation state for accumulating charges in each X-ray detection element.
The imaging environment is irradiated from the X-ray generator based on the output of the X-ray sensor in a period other than the period in which the detection means is performing the detection process and the period in which the charge is accumulated. It is equipped with a means for judging whether or not the environment has a high level of radiation other than X-rays.
The judgment unit may, if the photographing environment is determined to be the environment,
At least the detection means and the control means are interrupted in the operation toward shooting .
The notification means, X-rays imaging apparatus according to claim Rukoto to notify the subject that encourages user to perform the sensitivity adjustment of the X-ray sensor of X-ray imaging apparatus. Even when the determination means determines that the imaging environment is the environment and at least interrupts the operation of the detection means and the control means toward imaging, the detection process is performed before that. If it is determined that X-rays have been emitted from the X-ray generator based on the output of the X-ray sensor during the charge accumulation state that has been started and the start of X-ray irradiation has been detected and shifted, at least The X-ray image capturing apparatus according to claim 8 , wherein the detecting means and the controlling means continue an operation performed toward photographing.

Images