JP6801749B2 - Radiation imaging device - Google Patents

Description

The present invention relates to a radiation imaging device and relates to a radiation imaging device capable of detecting the start of irradiation of radiation.

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

This type of radiographic imaging device is known as an FPD (Flat Panel Detector), and has conventionally been configured as a so-called dedicated machine type (also referred to as a fixed type) formed integrally with a support base or the like. However, in recent years, a portable (also referred to as a cassette type) radiation imaging device in which a radiation detection element or the like is housed in a housing and can be carried has been developed and put into practical use (see, for example, Patent Document 1). For example, see Patent Documents 2 and 3).

In such a radiation imaging apparatus, for example, as shown in FIGS. 2 and 3 described later, a plurality of radiation detection elements 7 are usually arranged in a two-dimensional shape (matrix shape) on the detection unit P, and each of them is arranged. A switch element formed of a thin film transistor (hereinafter referred to as a TFT) 8 is connected to each of the radiation detection elements 7.

Then, usually, the radiation imaging is performed from the radiation generator 55 (see FIG. 5 described later) to the radiation imaging device via a predetermined imaging site such as the subject's body (that is, the front surface of the chest, the side surface of the lumbar spine, etc.). Radiation is applied in the state.

At that time, an off voltage is applied from the gate driver 15b of the scanning drive means 15 of the radiation imaging apparatus to each of the lines L1 to Lx of the scanning line 5 to turn off all TFTs 8 (charge accumulation state described later). By irradiating the radiation, the electric charge generated in each radiation detecting element 7 by the irradiation of the radiation is accurately accumulated in each radiation detecting element 7.

Then, after taking a radiation image, an on-voltage is sequentially applied from the gate driver 15b to each of the lines L1 to Lx of the scanning line 5, each TFT 8 is sequentially turned on, and the radiation is generated in each radiation detection element 7. The accumulated charge is sequentially discharged to each signal line 6, and the reading process of the image data D to be read as the image data D by each reading circuit 17 is performed.

By the way, as described above, in order to accurately perform radiation imaging, when radiation is applied to the radiation imaging device, the off voltage is appropriately applied from the gate driver 15b to each line L1 to Lx of the scanning line 5. Is applied, and it is necessary that each TFT 8 which is a switch element is turned off.

Therefore, for example, in a conventional dedicated radiation imaging device or the like, an interface is constructed with the radiation generating device, signals or the like are exchanged with each other, and the radiation imaging device performs each line L1 to Lx of the scanning line 5. In many cases, it is configured to irradiate radiation from a radiation generator after confirming that an off-voltage is applied to the radiation and the charge is accumulated.

However, for example, when the manufacturers of the radiation imaging device and the radiation generator are different, it may not always be easy to build an interface between them, or it may not be possible to build an interface. is there.

When an interface is not constructed between the radiation imaging device and the radiation generator in this way, it is not possible to know at what timing the radiation is emitted from the radiation generator when viewed from the radiation imaging device side. Therefore, the radiation imaging device must detect that the radiation is emitted from the radiation generator.

Therefore, in recent years, various radiation imaging devices have been developed that are configured to detect the irradiation by themselves, regardless of the interface between the radiation imaging device and the radiation generator. ..

For example, in Patent Document 4, a radiation imaging apparatus is configured to include a relatively small-sized radiation sensor (that is, a sensor configured as, for example, a module, which is separate from the radiation detection element), and the radiation sensor is irradiated. It is described that the radiation is detected to detect that the radiation imaging device has started to irradiate the radiation.

Further, for example, in Patent Document 5, the readout circuit 17 is made to perform a readout operation with all TFTs 8 (see FIG. 3 and the like described later) turned off before the radiation imaging apparatus is irradiated with radiation. It is described that the leak data dleak is read out and the device itself detects the start of radiation irradiation based on the read out leak data dleak.

Further, for example, in Patent Document 6, even before the radiation imaging apparatus is irradiated with radiation, the scanning drive means 15 and the readout circuit 17 are similarly operated to read the image data D as the main image to obtain the image data. It is described that the reading process is performed and the start of radiation irradiation is detected by the apparatus itself based on the read image data.

Further, for example, as described in Patent Document 7, the bias wire 9 connected to each radiation detection element 7 and the connection 10 thereof (see FIG. 3 and the like described later) are configured to be provided with current detecting means. Is also possible. In this case, when the radiation imaging apparatus is irradiated with radiation, electric charges are generated in each radiation detection element 7, and the current flowing through the bias line 9 and the connection 10 increases. Therefore, it is possible to detect the start of radiation irradiation based on the current value detected by the current detecting means.

Further, for example, as described in Patent Document 8, a part of the structure of the radiation detection element 7 arranged two-dimensionally as described above is changed to be a radiation detection pixel, and the radiation detection pixel is used. It is also possible to detect the start of radiation irradiation based on the output.

In the following, leak data leak due to the electric charge leaked from the radiation detection element 7 via the TFT 8 as described in Patent Documents 5 to 8, and leak data from each radiation detection element 7 to the bias line 9 and the like. The current value caused by the electric charge, or the data read from each radiation detection element 7 or the radiation detection pixel, etc., is simply referred to as "data from each radiation detection element 7 or the radiation detection pixel". .. The method of detecting the start of radiation irradiation based on the data from each of the radiation detection elements 7 and the radiation detection pixels is called the first detection method.

Further, a method of detecting the start of radiation irradiation based on a radiation sensor as described in Patent Document 4 is referred to as a second detection method.

Japanese Unexamined Patent Publication No. 9-73144 Japanese Unexamined Patent Publication No. 2006-58124 Japanese Unexamined Patent Publication No. 6-34209 JP-A-2010-104398 International Publication No. 2011/135917 Pamphlet International Publication No. 2011/152093 Pamphlet JP-A-2009-219538 Japanese Unexamined Patent Publication No. 2013-33030

By the way, for example, when radiation is applied to a radiation imaging device in a state where the irradiation field is narrowed down, in the above-mentioned second detection method using a radiation sensor, the radiation sensor is located outside the irradiation field. If radiation is applied to the surface, the start of radiation irradiation cannot be detected. On the other hand, if the above-mentioned first detection method is adopted, even if the irradiation field is narrowed down, in at least a part of the two-dimensionally arranged regions, the radiation detection element 7, the TFT 8, and the radiation detection pixel Since radiation is applied to either of them, the data from each radiation detection element 7 and the radiation detection pixel increases due to the irradiation of radiation, and the start of radiation irradiation can be detected.

As described above, one merit of adopting the first detection method is that the radiation is applied to the radiation imaging apparatus in a state where the irradiation field is narrowed down, and the narrowed irradiation field is two-dimensional. It can be mentioned that the start of irradiation of radiation can be accurately detected regardless of the region of the arranged radiation detection elements 7.

On the other hand, when the first detection method is adopted, when an impact, vibration, or the like is applied to the radiation imaging device due to the portable radiation imaging device hitting the patient's body, bed, or the like, the detection unit P has two. The vibration propagates to a part or all of a plurality of radiation detection element groups 7 arranged in a dimensional shape (matrix shape), and the leak data dleak or the like read out contains the original signal value + noise (originally). The value is larger than the signal of), and in some cases, even though the radiation imaging device is not irradiated with radiation, the leak data leak to be read exceeds the threshold value, and so on. May be falsely detected as being started. These are widely known in the field of radiography as microphonic phenomena.

In the diligent study by the present inventors, when the radiation imaging apparatus has a capacitor component, the distance between the pair of electrodes constituting the capacitor may physically fluctuate due to impact, vibration, or the like, and the output may fluctuate. I understand. In addition, the parasitic capacitance component of the harness or the like changes transiently due to the vibration of the harness and disturbs the potential balance with the radiation detection element to which the harness is connected, so that the output of the radiation imaging device also fluctuates. It has become clear that it will end up. It has also been found that a relatively large radiation detection element such as a detection element array in which radiation detection elements 7 are arranged in a two-dimensional shape (matrix shape) has a remarkable effect.

In that respect, if the above-mentioned second detection method using a radiation sensor is adopted, the output noise does not increase even when a disturbance such as vibration occurs in recent years, and it is difficult to erroneously detect the start of radiation irradiation due to the disturbance. A radiation sensor has been developed, and by using it, it is possible to accurately prevent erroneous detection of the start of radiation irradiation even when an impact, vibration, or the like is applied to the radiation irradiation device.

Therefore, while taking advantage of the advantages of each of these first and second detection methods, the radiation imaging device does not erroneously detect the start of irradiation when a disturbance such as impact or vibration is applied, and the radiation is emitted. It is desired to configure the structure so that the start of irradiation can be accurately detected when the radiation is irradiated.

The present invention has been made in view of the above problems, and by using the above-mentioned first and second detection methods, when a disturbance such as an impact or vibration is applied, the start of radiation irradiation can be erroneously detected. Instead, it is an object of the present invention to provide a radiation imaging apparatus capable of accurately detecting the start of irradiation when radiation is irradiated.

In order to solve the above problems, the radiographic imaging apparatus of the present invention is used.
Multiple radiation detection elements that are arranged in two dimensions and generate electric charges when they receive radiation ,
A switching element switched to the ON state to pre SL in the radiation detection element to accumulate charges Ruofu state, or out-release pre Symbol radiation charges accumulated in the detection element,
Receiving and the ray Sensor release for outputting the radiation,
To detect the start of irradiation of radiology and control means for controlling the state of the switching element,
Before Symbol control means,
Of radiation by a first detection system for detecting the start of irradiation based pre SL on data from the data or the portion of the radiation detection pixels structure is changed for each radiation detection element, from each radiation detection element The detection of the start of irradiation is repeated at a predetermined cycle, and the detection of the start of radiation irradiation by the second detection method of detecting the start of radiation irradiation based on the output value of the radiation sensor is defined as the detection by the first detection method. Repeat in the same cycle,
Wherein the first detection method with any of the methods of the second detection method or the detection of a start of irradiation by both schemes, characterized in that the said switching element in an off state.

According to the present invention, since it is detected that the radiation irradiation is started by at least one of the first detection method and the second detection method, it is possible to accurately detect the start of the radiation irradiation. ..

It is sectional drawing of the radiation imaging apparatus. It is a top view which shows the structure of the substrate of a radiation imaging apparatus. It is a block diagram which shows the equivalent circuit of a radiation imaging apparatus. It is a figure explaining that each charge leaked from each radiation detection element through each TFT is read out as leak data. It is a graph which shows the example of the time transition of the leak data read out. It is a timing chart explaining the timing of applying an on-voltage to each scanning line when detecting the start of radiation irradiation based on the leak data. It is a figure which shows the case where the radiation imaging apparatus is irradiated with the radiation which narrowed down the irradiation field. It is a graph which shows the example of the time transition of the average value for each read IC of the leak data read by each read circuit. It is a figure explaining the method of calculating a moving average. It is a graph which shows the example of the time transition of each difference calculated for each read IC. It is a graph which shows the example of the time transition of the maximum value of the calculated difference. It is a figure explaining the method of calculating a moving average different from the method shown in FIG. FIG. 5 is a cross-sectional view showing a state in which both ends of the sensor panel are housed in the housing while being held by internal portions on the side surface of the housing. It is sectional drawing which shows the structure of the vicinity of the end of the sensor panel of the radiographic imaging apparatus which concerns on this embodiment. It is the figure which looked at the sensor panel from above, and is the figure which shows the state which attached the conductive film to the conductive layer on the scintillator substrate. It is the figure which looked at the sensor panel from the lower side. It is sectional drawing which shows the structure which provided the acceleration sensor on the lower surface side of the base of the sensor panel. It is the figure which looked at the sensor panel from the lower side, and is the figure which shows the example which provided the acceleration sensor at the four corners and the center position on the lower surface side of a sensor panel. It is a figure which shows the amplifier output x (upper part) and digital output d (lower part) of (A) the conventional radiation sensor, and (B) the radiation sensor which concerns on this embodiment. It is the figure which looked at the radiation image taking apparatus from the upper side, and is the figure which shows the example which arranged one radiation sensor at the center position of a detection part. It is a figure which shows the example which arranged the plurality of radiation sensors in two regions which are not adjacent to each other on a rectangular detection part. It is a figure which shows the example which arranged each of a plurality of radiation sensors at the position deviated from the center line of the rectangular detection part.

Hereinafter, embodiments of the radiation imaging apparatus according to the present invention will be described with reference to the drawings.

In the following, a so-called indirect type radiation imaging device equipped with a scintillator or the like as a radiation imaging device and converting emitted radiation into electromagnetic waves of other wavelengths such as visible light to obtain an electric signal will be described. The present invention can also be applied to a so-called direct radiation imaging apparatus in which radiation is directly detected by a radiation detecting element without using a scintillator or the like.

Further, although the case where the radiation imaging device is a so-called portable type will be described, the present invention can also be applied to a dedicated machine type radiation imaging device integrally formed with a support base or the like. is there.

[Rough configuration of radiation imaging device]
Hereinafter, first, a schematic configuration of the radiation imaging apparatus 1 according to the present embodiment will be described. FIG. 1 is a cross-sectional view of the radiation imaging apparatus according to the present embodiment.

It should be noted that the relative size, length, etc. of each member of the radiation imaging apparatus 1 in each of the drawings shown in FIGS. 1 and 1 and below do not necessarily reflect the actual configuration of the radiation imaging apparatus. Further, in the following, in the vertical direction and the horizontal direction (horizontal direction), the radiation imaging apparatus 1 is arranged so that the radiation incident surface R, which is the surface on which the radiation is irradiated, faces upward as shown in FIG. The explanation will be given based on the arranged state. Therefore, for example, when the radiation imaging device 1 is arranged so that the radiation incident surface R faces the horizontal direction, the vertical direction in the following description is the horizontal direction in the radiation imaging device 1 in this state. Become.

As shown in FIG. 1, in the radiation imaging apparatus 1, a sensor panel SP composed of a scintillator 3 and a sensor substrate 4 is housed in a housing 2 formed of a carbon plate or the like having a radiation incident surface R. It is composed of. Further, although not shown in FIG. 1, in the present embodiment, the housing 2 has an antenna device 51 (FIG. 3 described later) which is a wireless communication means for transmitting image data D or the like to an external device by wireless method. See).

Further, although not shown in FIG. 1, in the present embodiment, the radiation imaging device 1 is provided with a connector 52 (see FIG. 3 described later) on the side surface of the housing 2, and is wired via the connector 52. It is possible to transmit signals, data, etc. to an external device by the method. Then, as shown in FIG. 3, which will be described later, the communication unit 50 to which the antenna device 51, the connector 52, and the like are connected functions as a communication means of the radiation imaging device 1.

In the present embodiment, the housing 2 of the radiographic imaging apparatus 1 is a bucky apparatus (not shown) capable of loading the radiographic imaging apparatus 1 with a cassette for a conventional screen / film or a cassette of a CR apparatus. JIS standard size (JISZ4) in cassettes for screens / films so that they can be loaded and used on a shooting table, etc.
It is formed in a size that conforms to 905), and is considered to be a compatible size with the CR cassette.

That is, it is formed so that at least the thickness dimension of the housing 2 in the radiation incident direction (that is, the direction orthogonal to the extending direction of the radiation incident surface R of the housing 2) is within the dimension range of 13 to 16 mm. Further, the size of the housing 2 is formed into various sizes such as 14 × 17 inches and 17 × 17 inches. The present invention can also be applied to a radiographic imaging apparatus that is not formed in a size conforming to such a JIS standard size.

As shown in FIG. 1, a lightweight and robust base 31 which is a basic strength member for the sensor panel SP and is made of resin or magnesium is arranged in the housing 2, and the radiation incident surface R of the base 31 is arranged. A thin lead plate for shielding radiation (not shown in FIG. 1, see FIG. 14 and the like described later) and the like are provided on the side, that is, the upper surface side, and the sensor substrate 4 is provided via them. Then, on the upper surface side of the sensor substrate 4, a scintillator 3 that converts the irradiated radiation into light such as visible light is provided on the scintillator substrate 34, which is a glass material having a thickness of 0.1 to 1 mm, and the scintillator 3 is a sensor. It is provided so as to face the substrate 4 side.
The scintillator is a columnar crystal type such as CsI, and is directly vapor-deposited on the scintillator substrate 34.

A scintillator separately manufactured in a sheet shape may be bonded to the scintillator substrate 34. In this case, it is necessary to be careful when assembling so that the scintillator assembly does not generate residual charge due to peeling charge, etc. at the time of bonding, peeling and re-bonding (each component of the assembly jig that eliminates static electricity from each part itself). It is preferable to perform common GND treatment on the parts, etc.), and further, perform static elimination on the finished product even after the scintillator assembly is completed.

Further, a PCB board 33, a battery 24, etc. on which electronic components 32 and the like are arranged are attached to the lower surface side of the base 31. A radiation sensor 25 is attached to the lower surface side of the base 31. In the present embodiment, the sensor panel SP is formed of the base 31, the sensor substrate 4, the scintillator substrate 34, and the like in this way, and the cushioning material 35 is provided between the sensor panel SP and the side surface of the housing 2. Has been done.

A more detailed configuration of the sensor panel SP will be described later. Further, although only one radiation sensor 25 is described in FIG. 1 and FIG. 3 described later, it is desirable to provide a plurality of radiation sensors 25 as described later. Further, how to attach the radiation sensor 25 to the radiation imaging device 1 and the like will be described in detail later.

In the present embodiment, the sensor substrate 4 is composed of a glass substrate having a thickness of 0.1 to 1 mm, and as shown in FIG. 2, the sensor substrate 4 is placed on the upper surface (that is, the surface facing the scintillator 3) 4a of the sensor substrate 4. The plurality of scanning lines 5 and the plurality of signal lines 6 are arranged so as to intersect each other. Further, a radiation detection element 7 is provided in each small region r partitioned by the plurality of scanning lines 5 and the plurality of signal lines 6 on the surface 4a of the sensor substrate 4.

The entire region in which the plurality of radiation detection elements 7 are arranged in a two-dimensional shape (matrix), that is, the region shown by the alternate long and short dash line in FIG. 2 is defined as the detection unit P capable of generating the radiation image information of the subject. .. That is, the detection unit P is a rectangular region in which a plurality of radiation detection elements 7 are two-dimensionally arranged on the sensor substrate 4. In the present embodiment, a photodiode is used as the radiation detection element 7, but for example, a phototransistor or the like can also be used.

Here, the circuit configuration of the radiation image capturing apparatus 1 will be described. FIG. 3 is a block diagram showing an equivalent circuit of the radiation imaging apparatus 1 according to the present embodiment.

The source electrode 8s (see “S” in FIG. 3) of the TFT 8 which is a switch element is connected to the first electrode 7a of each radiation detection element 7. Further, the drain electrode 8d and the gate electrode 8g of the TFT 8 (see “D” and “G” in FIG. 3) are connected to the signal line 6 and the scanning line 5, respectively.

Then, the TFT 8 is turned on when an on-voltage is applied to the gate electrode 8g from the scanning driving means 15 described later via the scanning line 5, and is accumulated in the radiation detection element 7 via the source electrode 8s and the drain electrode 8d. The charged charge is emitted to the signal line 6. Further, when an off voltage is applied to the gate electrode 8g via the scanning line 5, the off state is set, the emission of electric charge from the radiation detection element 7 to the signal line 6 is stopped, and the electric charge is accumulated in the radiation detection element 7. It is designed to let you.

Further, in the present embodiment, as shown in FIGS. 2 and 3, one bias is applied to the second electrode 7b of each radiation detection element 7 in a row for each radiation detection element 7 on the sensor substrate 4. The wires 9 are connected, and each bias wire 9 is connected to the connection 10 at a position outside the detection unit P of the sensor substrate 4.

The connection 10 is connected to the bias power supply 14 (see FIG. 3) via the input / output terminal 11 (also referred to as a pad; see FIG. 2), and is connected to the bias power supply 14 via the connection 10 and each bias wire 9. A reverse bias voltage is applied to the second electrode 7b of the radiation detection element 7.

On the other hand, each scanning line 5 is connected to the gate driver 15b of the scanning driving means 15 via the input / output terminal 11. 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 the on voltage and the off voltage respectively.

Further, each signal line 6 is connected to each read circuit 17 built in the read IC 16 via each input / output terminal 11. In the present embodiment, the read circuit 17 is mainly composed of an amplifier circuit 18 and a correlated double sampling circuit 19 and the like. Further, in the present embodiment, as shown in FIG. 4 described later, the amplifier circuit 18 is composed of a charge amplifier circuit in which the operational amplifier 18a and the capacitor 18b are connected in parallel, and the capacitor is connected from the output side of the operational amplifier 18a. A voltage value corresponding to the amount of electric charge stored in 18b is output.

As shown in FIG. 3, an analog multiplexer 21 and an A / D converter 20 are further provided in the readout IC 16. In FIG. 3, the correlated double sampling circuit 19 is referred to as CDS.

When the image data D is read out from each radiation detection element 7, when an on-voltage is applied to the scanning line 5 from the gate driver 15b of the scanning driving means 15 to turn on each TFT 8, these TFTs 8 are turned on. Charges are emitted from the inside of each radiation detection element 7 to the signal line 6 via each TFT 8. Then, as described above, in the amplifier circuit 18 of each readout circuit 17, a voltage value corresponding to the amount of charge flowing from the radiation detection element 7 into the capacitor 18b is output from the operational amplifier 18a to the correlated double sampling circuit 19 side.

The correlation double sampling circuit 19 outputs the increase in the output value from the amplifier circuit 18 before and after the electric charge flows from each radiation detection element 7 into the amplifier circuit 18 as analog image data D to the downstream side. 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 reading process is performed.

Further, in the reset process of each radiation detection element 7, an on-voltage is sequentially applied from the gate driver 15b to each of the lines L1 to Lx of the scanning line 5 (for example, see “R” in FIG. 6 described later) to detect each radiation. A charge is discharged from the element 7 to the signal line 6 via the TFT 8, and the charge flows downstream. By doing so, the electric charge remaining in each radiation detection element 7 is removed from each radiation detection element 7, and each radiation detection element 7 is reset.

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, etc. (not shown) are connected to the bus, an FPGA (Field Programmable Gate Array), or the like. It is configured. It may be composed of a dedicated control circuit.

Then, the control means 22 controls the operation of each functional unit of the radiation imaging apparatus 1 such as controlling the scanning driving means 15 and the reading circuit 17 to perform the reading process of the image data D as described above. It has become.

Further, as shown in FIG. 3, a storage means 23 composed of an SRAM (Static RAM), a SDRAM (Synchronous DRAM), or the like is connected to the control means 22. Further, in the present embodiment, the control means 22 is connected to the communication unit 50 to which the antenna device 51, the connector 52, and the like described above are connected, and further, the scanning drive means 15, the read circuit 17, the storage means 23, and the like. A battery 24 and a radiation sensor 25 that supply necessary power to each functional unit such as the bias power supply 14 are connected.

[About the detection process of the start of radiation irradiation in the radiation imaging device]
Here, the detection process of the start of irradiation of radiation performed by the radiation imaging apparatus 1 according to the present embodiment will be described.

In the present embodiment, as described above, the control means 22 has at least a first detection method for detecting the start of radiation irradiation based on data from each radiation detection element 7 and a radiation detection pixel (not shown), and radiation. It is configured to detect the start of radiation irradiation by a second detection method that detects the start of radiation irradiation based on the output value of the sensor 25.

Specifically, in the present embodiment, as the second detection method, the control means 22 detects the start of irradiation of radiation based on the value output from the radiation sensor 25 (see FIGS. 1 and 3 and the like) described above. You can do it.

That is, as the radiation sensor 25, for example, a semiconductor sensor or the like that increases the output current value, voltage value, or the like when irradiated with radiation can be used. Then, for example, a threshold value is set in advance for the value output from the radiation sensor 25, and the control means 22 starts irradiation of radiation when the value output from the radiation sensor 25 becomes equal to or higher than the threshold value. It can be configured to detect.

Next, the first detection method adopted in the present embodiment will be described. In the following, as the first detection method, a method of detecting the start of radiation irradiation based on the leak data leak described in Patent Document 5 described above will be described. However, in addition to this, as the first detection method, for example, the detection methods described in the above-mentioned Patent Documents 6 to 8 can be adopted, and each radiation detection element 7 and the radiation detection pixel can be adopted. It is also possible to adopt another detection method as long as it is a method of detecting the start of radiation irradiation based on the data from.

In the method of detecting the start of radiation irradiation based on the leak data dleak, first, an off voltage is applied to each scanning line 5 from the gate driver 15b (see FIG. 3) before the radiation imaging device 1 is irradiated with radiation. Then, with each TFT 8 turned off, each read circuit 17 is made to perform a read operation, and the read process of the leak data leak is repeated.

Gate driver 15b In a state where an off voltage is applied to each scanning line 5 to turn each TFT 8 into an off state, as shown in FIG. 4, leaks from each radiation detection element 7 via each TFT 8 in the off state. The charge q is stored in the capacitor 18b of the amplifier circuit 18. That is, the total value of the charges q leaked from each radiation detection element 7 is accumulated in the capacitor 18b of the amplifier circuit 18 via each TFT 8.

Therefore, when the read operation is performed by the read circuit 17 in this state, the voltage value from the output side of the operational amplifier 18a of the amplifier circuit 18 corresponds to the total value of the charges q leaked from each radiation detection element 7 via each TFT 8. Is output. Therefore, the data corresponding to the total value of the electric charges q leaked through each TFT 8 is read out. The data read in this way is leak data leak.

With this configuration, when the radiation imaging device 1 is started to be irradiated with radiation, the charge q leaking from the inside of each radiation detection element 7 to the signal line 6 via each TFT 8 increases. Therefore, it is known that the value of the leak data dleak to be read increases sharply when the radiation imaging apparatus 1 starts to be irradiated with radiation (see, for example, time t1 in FIG. 5).

Therefore, by utilizing the increase in the value of the leak data dleak, for example, as shown in FIG. 5, by detecting that the read leak data dleak is equal to or higher than the set threshold value dleak_th, the radiation is emitted. The image capturing device 1 itself can be configured to detect the start of radiation irradiation.

When the leak data dleak is used to detect the start of radiation irradiation, if an off voltage is applied to each scanning line 5 from the gate driver 15b as described above and each TFT 8 is left in the off state, Dark charges continue to be accumulated in each radiation detection element 7.

Therefore, for example, as shown in the left part of FIG. 6 to be described later, each radiation detection element 7 is between the reading process of the leak data leak (denoted as “L” in the figure) and the reading process of the next leak data leak. (Indicated as "R" in the figure) can be configured to perform the reset process.

When resetting each radiation detection element 7, as shown in FIG. 6, an on-voltage is sequentially applied from the gate driver 15b (see FIG. 3) of the scanning driving means 15 to each of the lines L1 to Lx of the scanning line 5. Although it is not shown, it is also possible to apply an on-voltage from the gate driver 15b to each of the lines L1 to Lx of the scanning line 5 all at once.

[Processing after detection of radiation start]
Then, in the present embodiment, the control means 22 has the above-mentioned first detection method (detection method based on data from each radiation detection element 7 and radiation detection pixel) and the second detection method (output of the radiation sensor 25). When the start of radiation irradiation is detected by any of the values-based detection methods), or when the start of radiation irradiation is detected by both methods, all TFTs 8 are turned off and inside the radiation detection element 7. It is designed to shift to a state where electric charge is accumulated.

That is, when the control means 22 detects the start of radiation irradiation because the read leak data charge is equal to or greater than the threshold value dleak_th, for example, in the first detection method, the start of irradiation is started as shown in FIG. At the time of detection (see "Detection" in the figure), an off voltage is applied from the gate driver 15b to each line L1 to Lx of the scanning line 5, all TFTs 8 are turned off, and each radiation detecting element 7 is irradiated with radiation. The charge generated in the radiation detection element 7 is shifted to a charge storage state in which the charge is accumulated in each radiation detection element 7.

Then, as shown in FIG. 6, the control means 22 is adapted to start the reading process of the image data D as the main image, for example, after a predetermined time has elapsed after shifting to the charge accumulation state.

In the present embodiment, in the image data D reading process, as shown in FIG. 6, the scanning line 5 to which the on-voltage is applied at the time when the start of irradiation of radiation is detected or immediately before that (in the case of FIG. 6, the scanning line 5). The on-voltage is applied to each scanning line 5 from the gate driver 15b by starting the application of the on-voltage from the scanning line 5 (in the case of FIG. 6, the line L5 of the scanning line 5) to which the on-voltage should be applied next to the line L4). The image data D as the main image is read out by sequentially applying the voltage.

The method of reading the image data D is not limited to this, and although not shown, the reading process of the image data D as the main image is performed, for example, by applying on-voltage in order from the first line L1 of the scanning line 5. It is also possible to configure it to be performed sequentially.

[About the improved method of detecting the start of radiation irradiation]
The above-mentioned first detection method can be improved as follows, for example. In the following, the case where the start of radiation irradiation is detected based on the read leak data dleak will be mainly described. Further, these improved detection methods are also described in Japanese Patent Application Laid-Open No. 2012-176155 submitted earlier by the applicant of the present application, and for details, refer to the same publication.

When a detection method based on leak data dleak is adopted, thousands to tens of thousands of signal lines 6 are usually wired to the detection unit P (see FIGS. 2 and 3) of the radiographic imaging apparatus 1. Since each signal line 6 is provided with a read circuit 17, the number of leak data leaks read in one read process of the leak data leak is from several thousand to several tens of thousands.

Then, if all the leak data leaks are configured to perform the process of determining whether or not the threshold value is greater than or equal to the threshold value dleak_th as described above for each read-out process, the detection process of the start of radiation irradiation is very high. It becomes heavy. Therefore, for example, it is possible to reduce the number of data to be determined and perform the detection process as follows.

Specifically, in the present embodiment, for example, 128 or 256 read-out circuits 17 are built in the read-out IC 16 (see FIG. 3) described above. That is, the signal lines 6 are connected to the read circuits 17 such as 128 and 256 in one read IC 16, respectively, and the signal lines 6 are connected from one read IC 16 in one read process of the leak data leak. Leak data such as 128 or 256 leak data leaks are read out for each.

Therefore, for example, the average value, the total value, the intermediate value, the maximum value, etc. of 256 leak data leaks output from one read IC 16 in one read process of the leak data leak, etc. (hereinafter, these are collectively statistical). ) Is calculated. Then, it is determined whether or not the statistical value dleak_st (z) of the leak data dleak calculated for each read IC 16 becomes equal to or greater than the threshold value dthA set for the statistical value dleak_st (z). It is possible to configure. Note that z is the number of the read IC 16.

With this configuration, for example, the detection unit P is provided with 4096 signal lines 6, and one read IC 16 contains 128 read circuits 17 (that is, one read IC 16 has 128 signal lines). (The signal line 6 is connected), the total number of read ICs 16 is 4096 ÷ 128 = 32.

Therefore, with the above configuration, for example, the detection process that had to determine whether or not the leak data dleak for 4096 pieces had exceeded the threshold value dleak_th was 32 statistical values dleak_st (z) (z) (z). = 1-32) It is only necessary to make a judgment, and the detection process can be lightened.

[Difference method]
Further, in order to further lighten the above-mentioned determination process in the detection process, the control means 22 calculates, for example, 32 statistical values from the leak data leak output from each read IC 16 in the read process of the leak data dleak once. It is also possible to extract the maximum value from the dleak_st (z) and determine whether or not the maximum value of the leak data dleak statistical value dleak_st (z) exceeds the threshold value.

With this configuration, it is only necessary to determine whether or not one maximum value extracted from the 32 statistical values dleak_st (z) exceeds the threshold value, and the detection process becomes very light. ..

However, since the read characteristics are usually different for each read IC 16, even if the total value of the charges q (see FIG. 4) leaking from each radiation detection element 7 to the signal line 6 is the same for each signal line 6. Some read ICs 16 have a leak data leak statistic that is always larger than the other read ICs 16, and some read ICs 16 have a leak data leak statistic that is always smaller than the other read ICs 16. ..

Then, in such a situation, as shown in FIG. 7, for example, consider a case where the radiation imaging apparatus 1 is irradiated with radiation in a state where the irradiation field F is narrowed down to the central portion of the detection unit P.

At this time, if the signal line 6a connected to the read-out IC 16 whose leak data leak statistical value dleak_st (z) is always larger than that of the other read-out IC 16 exists outside the irradiation field F, for example, as shown in FIG. Even if the leak data dleak statistical value dleak_st (z) (see γ in the figure) output from the readout IC 16γ to which the signal line 6 existing in the irradiation field F is connected rises due to irradiation, the irradiation field There may be a case where the signal line 6a existing outside the F is not equal to or more than the leak data dleak statistical value dleak_st (z) (see δ in the figure) output from the connected read IC 16δ.

Then, in such a case, when the maximum value is extracted from the statistical value dleak_st (z) of the leak data dleak in each read IC 16, the statistical value dleak_st (z) of the leak data dleak indicated by δ in the figure is extracted. However, the statistical value dleak_st (z) of the extracted leak data dleak does not fluctuate even when irradiated with radiation. Therefore, the maximum value of the statistical value dleak_st (z) of the extracted leak data dleak does not exceed the threshold value, and eventually the radiation irradiation cannot be detected.

Therefore, in order to avoid such a problem, for example, it is possible to adopt a method using the following moving average.

That is, for each read process, the moving average dlst_ma (z) is calculated based on the statistical value dleak_st (z) of the leak data dleak output from each read IC 16.
Specifically, every time the statistical value dleak_st (z) of the leak data dleak output from the read IC 16 is calculated during the read process of the leak data dleak, as shown in FIG. 9, the read immediately before the read process is performed. The average of the leak data dleak statistical value dleak_st (z) (that is, the moving average dlst_ma (z)) calculated at the time of each past reading process for a predetermined number of times (for example, 10 times) including the processing is calculated. Configure to calculate.

In this case, as a method for calculating the moving average dlst_ma (z), a known method such as a simple moving average, a weighted moving average, or an exponential moving average can be used.

Then, according to the following equation (1), the difference Δd (z) between the statistical value dleak_st (z) of the leak data dleak calculated in the current read process and the calculated moving average dlst_ma (z) is calculated for each read IC 16. Configure to do.
Δd (z) = dleak_st (z) −dlst_ma (z)… (1)

In this way, the control means 22 calculates the statistical value dleak_st (z) from the leak data dleak output from the read IC 16 in one read process of the leak data dleak, and at the same time, moves corresponding to each. The difference Δd (z) from the average dlst_ma (z) is calculated for each read IC 16.

Then, the maximum value Δdmax is extracted from the calculated difference Δd (z) (32 differences Δd (z) in the above example), and whether or not the maximum value Δdmax of the difference Δd (z) becomes the threshold value Δdth or more. It can be configured to determine. The method for detecting the start of radiation irradiation based on such a detection method is hereinafter referred to as a difference method.

With this configuration, even if the read characteristics vary from read IC 16 to read IC 16, the statistical value of leak data dleak read under the same read characteristics in the same read IC 16 dleak_st (z) and the moving average dlst_ma ( By calculating the difference Δd (z) from z), the variation due to the read characteristics of each read IC 16 is offset.

That is, even if there are variations in the readout characteristics of each readout IC 16 as shown in FIG. 8, as shown in FIG. 10, unless the radiation imaging apparatus 1 is irradiated with radiation, the readout ICs 16γ and 16δ are described above. The value of the calculated difference Δd (z) becomes almost 0 in any of the readout ICs 16 including the above (see γ and δ before the start of radiation irradiation in FIG. 10).

Therefore, the above difference Δd (z) becomes a value that purely reflects whether or not the statistical value of leak data dleak, dleak_st (z), has increased from the past data for each read IC 16, and based on this, the radiation By configuring so as to detect the start of irradiation, it is possible to accurately prevent the problem as shown in FIG. 8 from occurring.

Further, when the radiation imaging device 1 is started to be irradiated with radiation (see time T1 in FIG. 11), a statistical value based on the leak data leak read in the current read process by at least one read IC16. The dleak_st (z) becomes much larger than the moving average dst_ma (z), and as shown in FIG. 11, the maximum value Δdmax of the difference Δd (z) is surely equal to or more than the threshold value Δdth. Therefore, it is possible to accurately detect that the irradiation of radiation has started.

As described above, in the present embodiment, when the moving average dlst_ma (z) is calculated, as shown in FIG. 9, a predetermined number of times including the reading process immediately before the reading process of the leak data dleak this time (for example, It is possible to calculate the moving average dlst_ma (z) for the leak data dleak statistical value dleak_st (z) for each read IC 16 calculated during each of the past read processes for 10 times).

However, instead of configuring in this way, as shown in FIG. 12, a predetermined number of times (for example, 10 times) including a predetermined number of times (for example, 10 times, 50 times, etc.) before the reading process of the leak data dleak this time is included. It is also possible to configure the moving average dlst_ma (z) to be calculated for the leak data dleak statistical value dleak_st (z) for each read IC 16 calculated in each past read process of the minute.

[Integration method]
On the other hand, when the dose rate of the radiation emitted from the radiation generator 55 to the radiation imaging device 1 is very small, the statistical value such as the average value of the leak data dleak for each read IC 16 calculated as described above dleak_st ( z) becomes smaller. Then, even if the radiation imaging apparatus 1 is irradiated with radiation, there may be a case where the statistical value dleak_st (z) does not exceed the threshold value dthA.

Similarly, when the above difference method is adopted, the statistical value of leak data dleak for each read IC 16 when the radiation imaging apparatus 1 is irradiated with radiation and the moving average dlst_ma (z) The difference Δd (z) may become small, and even if the radiation imaging apparatus 1 is irradiated with radiation, the difference Δd (z) may not exceed the threshold value Δdth.

However, in that case, even if the above difference method is adopted, the radiation imaging device 1 may not be able to detect the start of irradiation even though the radiation imaging device 1 is irradiated with radiation. You will get it.

Therefore, for example, for each read IC 16, a temporal integrated value (also referred to as an integrated value) ΣΔd of the difference Δd (z) between the statistical value dleak_st (z) of the leak data dleak and the moving average dlst_ma (z) is calculated. It is configured as follows. Then, it can be configured to determine whether or not there is a read IC 16 in which the integrated value ΣΔd is equal to or greater than the threshold value ΣΔdth. The method for detecting the start of radiation irradiation based on this detection method is hereinafter referred to as an integration method.

With this configuration, although not shown, the statistical value of leak data dleak, dleak_st (z), fluctuates and becomes larger or smaller than the moving average dlst_ma (z) until the radiation imaging device 1 is irradiated with radiation. Or become. Therefore, the integrated value ΣΔd of the difference Δd (z) changes at a value close to 0.

However, when the irradiation of the radiation imaging apparatus 1 with radiation is started, the statistical value dleak_st (z) of the leak data dleak becomes a significantly larger value than the moving average dlst_ma (z), and therefore the difference Δd (z) between them. ) Is often a positive value. Therefore, with the above configuration, when the radiation imaging device 1 is started to be irradiated with radiation, the integrated value ΣΔd increases and becomes equal to or higher than the threshold value ΣΔdth.

Therefore, even when the dose of radiation emitted from the radiation generator 55 to the radiation imaging device 1 is very small, it is possible to accurately detect the start of irradiation of the radiation to the radiation imaging device 1.

In this integration method, unless the number of times the difference Δd (z) is integrated is limited, the integrated value ΣΔd will be increased as the difference Δd (z) is integrated even if the radiation imaging apparatus 1 is not irradiated with radiation. The threshold value becomes ΣΔdth or more, and it is erroneously detected that the radiation imaging apparatus 1 is irradiated with radiation. Therefore, when the integration method is adopted, it is desirable to limit the number of integrations of the difference Δd (z) to a predetermined number.

[About the configuration peculiar to the present invention]
Next, the configuration and the like peculiar to the present invention in the radiation imaging apparatus 1 will be described. In addition, the operation of the radiographic imaging apparatus 1 according to the present embodiment will also be described.

In the present embodiment, as shown in FIG. 13, the sensor panel SP formed of the sensor substrate 4 and the scintillator substrate 34 described above is held in a state where both ends thereof are held by internal portions on the side surface of the housing 2. It is housed in the housing 2. Note that FIG. 13 is a cross-sectional view in the direction orthogonal to FIG.

Specifically, in the present embodiment, in the housing 2 of the radiation imaging apparatus 1, the lid members 2B and 2C are fitted into the openings on both side surfaces of the square tubular main body 2A having the radiation incident surface R. It is formed so as to be. Inside the lid members 2B and 2C, insertion portions 2B1 and 2C1 into the main body portion 2A are provided, respectively, and recesses are formed in the insertion portions 2B1 and 2C1, respectively. Further, buffer members 2B2 and 2C2 having a substantially U-shaped cross section are fitted into the recesses of the insertion portions 2B1 and 2C1, respectively.

Then, when the lid members 2B and 2C are fitted into the openings of the main body 2A after the sensor panel SP is inserted into the main body 2A of the housing 2, the cushioning members 2B2 and 2C2 provided inside the lid members 2B and 2C By fitting both ends of the sensor panel SP into the housing 2, the sensor panel SP is housed in the housing 2 in a state where both ends of the sensor panel SP are held in the inner portions of the side surfaces of the housing 2. It has become so.

Therefore, in the radiation imaging apparatus 1 of the present embodiment, the end portion of the sensor panel SP is supported inside the housing 2 via the cushioning members 2B2, 2C2 and the cushioning material 35 (see FIG. 1). However, other parts of the sensor panel SP are not held in the housing 2. That is, the sensor panel SP is in a floating state except for the end portions supported by the cushioning members 2B2 and 2C2 and the cushioning material 35.

With this configuration, even if a large impact is applied to the housing 2 by dropping the radiation imaging device 1, for example, the impact causes the cushioning members 2B2, 2C2 and the cushioning material 35 to be applied to the sensor panel SP. Since it is transmitted through the sensor panel SP, there is an advantage that the sensor panel SP does not receive much damage.

On the other hand, in such a configuration, when vibration is transmitted from the housing 2 to the sensor panel SP, even if the vibration of the housing 2 subsides thereafter, the vibration of the sensor panel SP continues for a while inside (that is, vibration damping). It has become clear that it may take a long time.

When the sensor panel SP vibrates in this way, the residual charges inherent in the sensor substrate 4 and the scintillator substrate 34, etc., which constitute the sensor panel SP, are locally concentrated and the potential balance is disturbed, and the radiation detection elements 7 and the like are affected. The degree of influence changes due to vibration, and when the above-mentioned first detection method is adopted, the value of the read leak data dleak or the like changes due to the influence (that is, fluctuation of the potential balance) and becomes equal to or higher than the threshold dleak_th. , Even though the radiation is not irradiated, it may be erroneously detected that the radiation irradiation has started.

Then, in the configuration shown in FIGS. 1 and 13, the vibration of the sensor panel SP may continue for a while inside the housing 2 as described above, so that the radiation due to the vibration or the like as described above may be generated. False detection of the start of irradiation may occur easily.

Therefore, in the present embodiment, by adopting a peculiar configuration as shown below, a device is made to prevent erroneous detection of the start of radiation irradiation and the like.

Although the case where the lid members 2B and 2C are fitted into the opening of the square tubular main body 2A to form the housing 2 is described in FIG. 13, for example, the upper member and the lower member are combined to form a housing. It is a so-called lunch box type housing that is a body, and a cushioning member is provided on the lower member, the sensor panel SP is placed on the cushioning member, the upper member is finally covered, and the upper and lower members are fixed with screws or the like. The assembly method to be performed also has the same problems as those in the present embodiment described above. Therefore, the present invention can also be applied to a radiation imaging device in which the housing 2 is a lunch box type.

[Unique configuration 1]
FIG. 14 shows a cross-sectional view showing a more detailed configuration near the end of the sensor panel SP of the radiation imaging apparatus 1 according to the present embodiment.

In FIG. 14, the PCB 33 on the lower surface side of the sensor panel SP, the electronic component 32, the battery 24, the radiation sensor 25, etc. (see FIG. 1 and the like) are not shown. Further, in FIG. 14, 44 represents a flexible circuit board connected to the input / output terminal 11, and 45 prevents moisture in the outside air from flowing into the internal space IS via the adhesive 37. Represents a moisture-proof insulating resin for use. Further, although not shown, the above-mentioned readout IC 16 and the like are incorporated on the flexible circuit board 44, and the scanning line 5, the signal line 6, and the bias on the sensor board 4 pass through the flexible circuit board 44. The wire 9 and the like are connected to the electronic device 32 under the sensor panel SP.

As shown in FIG. 14, in the present embodiment, the sensor substrate 4 in which the scanning line 5, the signal line 6, the radiation detection element 7, the TFT 8, the bias line 9, and the like are formed on the upper surface 4a, and the scintillator supporting the scintillator 3 The substrate 34 is arranged so that the radiation detection element 7 and the scintillator 3 face each other. In FIG. 14, the radiation detection element 7 and the like are filled with the flattening layer 36 so that the relative positional relationship between the scintillator and the radiation detection element is constant, and the potential balance due to vibration, the parasitic capacitance, and the like are checked. The configuration is such that fluctuations are unlikely to occur (that is, the configuration is less susceptible to the microphonic effects described above).

Then, the sensor substrate 4 and the scintillator substrate 34 are formed by the adhesive 37 which is applied to the peripheral portion of the radiation detection element 7 and the scintillator 3 in the gap portion between the sensor substrate 4 and the scintillator substrate 34 and finally cured. Is pasted so that the relative positional relationship is fixed. In the present embodiment, when the sensor substrate 4 and the scintillator substrate 34 are attached, the adhesive 37 is used so that the internal space IS surrounded by the sensor substrate 4, the scintillator substrate 34, and the adhesive 37 is depressurized. An opening for decompression intake is provided in a part thereof, and then the opening is filled with an adhesive 37 and finally cured. In the present embodiment, it is possible to use a known adhesive such as a thermosetting resin or an ultraviolet curable resin as the adhesive 37, but since the curing process can be completed in a short time, it is cured by ultraviolet treatment. It is preferable to use a UV curable adhesive.

Further, in order to prevent the scintillator substrate 34 and the like from warping, a warp prevention layer 38 can be provided on the upper surface of the scintillator substrate 34 (that is, the surface opposite to the surface on which the scintillator 3 is formed). For example, the warpage of the scintillator substrate 34 can be suppressed by adhering or applying a material having a different thermal expansion or contraction to the scintillator substrate 34. Materials used for the warp prevention layer 38 of the present invention include polyethylene terephthalate, polyethylene naphthalate, cellulose acetate, polyamide, polyimide, polyetherimide, epoxy, polyamideimide, bismarayimide, fluororesin, acrylic, polyurethane, aramid, and the like. Examples thereof include nylon, polycarbonate, polyphenylene sulfide, polyether sulfone, poly sulfone, polyether ether ketone, liquid crystal polymer, and carbon fiber reinforced resin sheet. Then, one of these materials may be used to form the warp prevention layer 38 as a single layer, or layers made of a plurality of materials may be laminated to form the warp prevention layer 38. Further, another functional layer such as an adhesive layer, a conductive layer, and a moisture-proof layer can be provided between the scintillator substrate 34 and the warp prevention layer 38.

In the present embodiment, as a unique configuration 1, as shown in FIG. 14, from, for example, ITO (Indium Tin Oxide) or the like on the upper surface side of the scintillator substrate 34, for example, between the scintillator substrate 34 and the resin layer 38. The conductive layer 39 is formed. However, the present invention is not limited to this, and the conductive material to be composed may be either an organic material or an inorganic material. Organic systems include polypyrrole, polyaniline, polythiophene, polyisothianaphene, polyethylenedioxythiophene, polyacetylene, polyparaphenylene, polyparaphenylene vinylene, polythienylene vinylene, polyfluorene, polyacene, and poly (3,4-dialkylpyrrole). ), Poly (aniline sulfonic acid) and other conductive polymers, carbon and the like. Examples of the inorganic system include metals such as aluminum, copper, silver and nickel, metal oxides such as SiO2, TiO2, Al2O3, ZrO2, MgO and ZnO, and ITO composed of indium metal oxide (In2O3) and tin metal oxide. Can be mentioned.

Examples of the conductive layer 39 include a sheet-like or tape-like material in which a conductive material is applied on a substrate, and a conductive cloth obtained by plating an extremely thin metal on the surface of an organic fiber. The sheet-shaped or tape-shaped conductive member may have an adhesive layer on the sheet surface, and is preferably adhered to the scintillator substrate 34 or the warp prevention layer 38 on the entire surface in order to prevent the occurrence of peeling charge or the like. ..

As a method for producing the conductive layer 39, a coating agent containing a conductive material is applied to a sheet or tape-like substrate to form a film, a solution coating method or an extrusion coating method, or a conductive component is melted. A kneading method in which the metal (target) is heated and vapor-deposited in a vacuum and coated on the substrate surface, a sputtering method, or a film-like conductive substance is bonded to the base material. A laminating method and the like can be mentioned. Further, the conductive material may be printed on a desired shape by using various printing methods.

The surface resistance of these conductive members, in the case of general antistatic applications ^{10 9 Ω / □ ~10 5 Ω} / □, in the case of conductive applications preferably 10 ⁵ Ω / □ or less.

A conductive film 40 is connected to the conductive layer 39, and the conductive film 40 is not shown in FIG. 14, but is also referred to as a reference GND (common GND or the like) of the electronic device 32 (see FIGS. 1 and 13). The same applies below.) It is electrically connected. Specifically, as shown in FIG. 14, the conductive layer 39 is laminated on the upper surface of the scintillator substrate 34. Then, the warp prevention layer 38 is attached and arranged above the warp prevention layer 38.

Then, at that time, as shown in FIG. 15 when the sensor panel SP is viewed from above, for example, a part of the warp prevention layer 38 is cut out to expose the conductive layer 39. Then, the conductive film 40 is attached to the portion by adhering it to the portion via a conductive double-sided tape (not shown) or the like.

Further, the conductive layer 39 itself may be extended to form the conductive film 40. When the conductive layer 39 and the conductive film 40 are integrally formed, it is preferable that the scintillator on which the image is formed (that is, the conductive layer 39 portion) is made of a material having good radiation permeability such as a conductive polymer, and the conductive film. Since the 40 portion has a small area and is required to have a high conductive function, it is preferable to form the 40 portion so that, for example, a metal or the like is densely formed. In this way, even when the conductive layer 39 and the conductive film 40 are integrally formed, it is possible to use different materials for the portion of the conductive layer 39 and the portion of the conductive film 40, or for example, the conductive layer 39. And the part of the conductive film 40 are both formed of a conductive polymer or the like, and a metal or the like is further arranged in the conductive polymer or a metal layer is provided on the part of the conductive film 40 to form a multilayer. It is also possible to configure it to be. It is also possible to add a functional layer such as a protective layer or a corrosion prevention layer to the conductive layer 39 and the conductive film 40.

Then, the tongue-shaped portion in which the conductive film 40 is extended is provided on the sensor panel SP on which the electronic component 32 provided on the side of the base 31 opposite to the side on which the scintillator substrate 34 or the like is provided is arranged. The conductive layer 39 is electrically connected to the reference GND of the electronic device 32 via the conductive film 40 by being routed to the lower surface side and connected to the reference GND electrode of the electronic component 32 or the like.

In the present embodiment, as shown in FIG. 16 when the sensor panel SP is viewed from below, a sensor is placed on the back surface side of the sensor panel SP via an electronic device 32, a battery 24, etc., as well as the above-mentioned flexible circuit board 44. A substrate 46 (hereinafter referred to as a readout substrate 46) connected to a signal line 6 (see FIG. 2 and the like) on the surface side of the substrate 4, and a scanning line 5 on the surface side of the sensor substrate 4 via a flexible circuit board 44. A substrate 47 to be connected (hereinafter referred to as a gate substrate 47) and the like are provided. The readout board 46 and the gate board 47 are also included in the electronic device 32.

Further, the electronic device 32 and the read-out board 46, the gate board 47, and the like are connected via the harness 48, respectively. The wiring for connecting the battery 24, the electronic device 32, the readout board 46, the gate board 47, the antenna 51 and the connector 52 (see FIG. 3), which are not shown in FIG. 16, is not shown.

Then, in the present embodiment, for example, the read-out substrate 46 and the gate substrate 47 are formed with exposed portions of the reference GND electrodes 46a and 47a, and the wiring and the like are tightened and fixed to these portions with screws 46b and 47b. You can do it.
The reference GND electrodes 46a and 47a are connected to a common conductive pattern portion (not shown) in order to keep these electrodes at the same potential.

Therefore, the conductive film 40 (see FIG. 14) attached to the conductive layer 39 formed on the upper surface of the scintillator substrate 34 as described above is routed to the lower surface side of the sensor panel SP, and the readout substrate 46 and the gate substrate are routed as described above. By attaching to the reference GND electrodes 46a, 47a of 47 by fixing them with screws 46b, 47b, etc., the conductive layer 39 is configured to be electrically connected to the reference GND of the electronic device 32 via the conductive film 40. Is possible.

As described above, when vibration or the like is applied to the radiation imaging apparatus 1, the sensor panel SP vibrates, and each radiation detection of the residual charge generated on the sensor substrate 4 and the scintillator substrate 34 constituting the sensor panel SP is detected. One of the causes is that the degree of influence on the element 7 and the like changes due to vibration (that is, the potential balance is disturbed by locally concentrating from the total dispersion), and the value of the leak data leak etc. changes due to the influence and the threshold value. When it became dleak_th or higher, it may be erroneously detected that the irradiation of radiation was started.

However, it is configured as in the above-mentioned unique configuration 1, a conductive layer 39 is formed on the upper surface of the scintillator substrate 34, and is electrically connected to the reference GND of the electronic device 32 via the conductive film 40 or the like. As a result, even if residual charges are present on the scintillator substrate 34, they are dispersed by the conductive layer 39 and local concentration does not occur, so that the potential balance is not disturbed and the influence on the leak data leak to be read is reduced. be able to.

[effect]
As described above, according to the radiation imaging apparatus 1 according to the present embodiment, the conductive layer 39 is formed on the upper surface side of the scintillator substrate 34, and the conductive layer 39 is electrically connected to the reference GND of the electronic device 32. It was configured to. Then, the control means 22 of the radiation imaging apparatus 1 is based on the first detection method for detecting the start of radiation irradiation based on the data from each radiation detection element 7 and the radiation detection pixel, and the output value of the radiation sensor 25. When the start of radiation irradiation is detected by one of the second detection methods for detecting the start of radiation irradiation based on the above, or by both methods, the switch element TFT8 is turned off and the charge is accumulated. It was configured to shift and take radiographic images.

Therefore, even if the residual charge remains on the scintillator substrate 34 during the manufacturing process, it is dispersed by the conductive layer 39 and local concentration does not occur, so that the potential balance is not disturbed and the leak data is read out. It is possible to reduce the influence on the above. Further, even if the removal rate of the electric charge (static electricity) inherently remaining on the scintillator substrate 34 due to the static electricity generated in the manufacturing process or the peeling charge is not 100%, it is allowed to reach a predetermined level. It is also possible to improve the yield.

Further, since the conductive layer 39 does not prevent the radiation irradiated to the radiation imaging device 1 from reaching the scintillator 3, when the radiation imaging device 1 is irradiated with radiation, each radiation detecting element 7 or The value of the data from the radiation detection pixel increases accurately. Therefore, when the radiation imaging apparatus 1 is irradiated with radiation, it is detected that the radiation irradiation is started by at least one of the first detection method and the second detection method. According to the radiation imaging apparatus 1 according to the above, when the radiation imaging apparatus 1 is irradiated with radiation, it is possible to accurately detect the start of irradiation of the radiation.
It should be noted that even if the thickness of the conductive layer 39 is changed (that is, even if the thickness is changed to 50 μm, 100 μm, 150 μm, for example), there is little difference in the above effects, and it is important to provide the conductive layer itself. Has also been obtained.

[Unique configuration 2]
On the other hand, as described above, the sensor panel SP is provided with a thin lead plate for shielding the radiation so that the radiation irradiated to the radiation imaging device 1 does not reach the electronic device 32 on the lower surface side of the sensor panel SP. Although it is provided, for example, it is also possible to utilize the thin plate of lead in the same manner as the above-mentioned conductive layer 39 to remove static electricity generated in the sensor substrate 4.

Specifically, as shown in FIG. 14, in the present embodiment, a cushioning material 41 and a lead thin plate 42 are provided between the sensor substrate 4 and the base 31 below the sensor substrate 4. Since the lead thin plate 42 having a thickness of 100 to 200 μm easily bends by itself, in the present embodiment, the lead thin plate 42 is sandwiched between the conductive PET resin plates 43 and 43 from above and below. It is configured to ensure the flatness of 42.

Then, in this unique configuration 2, as shown in FIG. 14, the lead thin plate 42 is used as a reference for the electronic component 32 arranged on the lower surface side of the sensor panel SP as in the case of the conductive layer 39. It can be configured to be electrically connected to the GND.

In this case, the conductive film 40 and the lead plate are both fixed to the reference GND (for example, the reference GND electrodes 46a and 47a of the readout substrate 46 and the gate substrate 47 shown in FIG. 16), that is, a so-called co-tightening state. Therefore, the potential balance over the entire sensor panel SP is stabilized, and the above-mentioned local concentration is less likely to occur.

In the sensor panel SP of the conventional radiographic imaging apparatus 1, the lead thin plate 42 may be formed only on the upper portion of the electronic device 32 and not on the end portion of the sensor substrate 4. However, with such a configuration, if residual charges are present at the end of the sensor substrate, local concentration may occur due to vibration or the like and the potential balance may be disturbed, leading to erroneous detection of the start of irradiation. Although there is a risk, as shown in FIG. 14, the risk can be reduced by configuring the lead thin plate 42 to extend to the end portion of the sensor substrate 4.

Further, even if the above-mentioned unique configuration 1 or unique configuration 2 is adopted, as shown in FIG. 14, the upper surface of the end portion of the sensor substrate 4 on which the input / output terminals 11 and the like (see FIG. 2) are formed. It is difficult to remove the static electricity on the 4a side.

The flexible circuit board 44 is susceptible to the local concentration of residual charges remaining on the end of the sensor board 4, and the lead thin plate 42 is configured to extend to the end of the sensor board 4. , It is possible to suppress the influence.
Further, regarding the surface of the moisture-proof insulating resin 45 and the flexible circuit board 44, if residual charges are inherent in the manufacturing process of the sensor panel SP, large noise is likely to be superimposed on the signal value due to local concentration even at low level vibration, and the residual charges are generated. It is necessary to perform sufficient (100%) static elimination so that it does not occur.

Further, when the sensor panel SP is loaded from one opening of the housing 2, as shown in FIG. 1, the cushioning materials 35 on both sides are loaded while being rubbed against the inner wall of the square tubular housing. , May generate residual charge due to triboelectric charging. As shown in FIGS. 6 and 7 of JP-A-2010-160044, since the cushioning material 35 and the flexible circuit board described above are arranged alternately, the residual charge is also locally concentrated. Will be affected by.

Therefore, as shown in FIG. 7 of the same publication, it is preferable to provide a sliding member (sheet such as PET) straddling each cushioning material to facilitate loading and prevent triboelectric charging. Further, it is preferable that the sliding member is made conductive and bent up and down as shown in FIG. 11 of the same publication to cover the flexible circuit board, so that local concentration of residual charge can be prevented. Further, it is preferable that the cushioning material itself is also conductive. Further, when the flexible circuit board is arranged on the side to be inserted into the opening, one conductive sliding sheet disclosed in Japanese Patent Application Laid-Open No. 2010-276658 is arranged by being bent in the vertical direction. However, it is preferable to cover the peripheral portion of the flexible circuit board because local concentration of residual charge can be prevented.

[Unique configuration 3]
Further, for example, as shown in FIG. 17, an acceleration sensor 26 for detecting the acceleration generated in the sensor panel SP is provided on the lower surface side of the base 31 of the sensor panel SP, that is, on the lower surface side of the PCB substrate 33, for example. It is also possible to do. In this case, the acceleration sensor 26 may be, for example, a so-called three-dimensional sensor or a two-dimensional sensor that detects the acceleration three-dimensionally or two-dimensionally, but at least one that can detect the acceleration in the vertical direction of the sensor panel SP. Used.

Then, as described above, the control means 22 of the radiation imaging apparatus 1 has the above-mentioned first detection method (detection method based on data from each radiation detection element 7 and radiation detection pixel) and the second detection method. When the start of radiation irradiation is detected by any of the methods (detection method based on the output value of the radiation sensor 25), or when the start of radiation irradiation is detected by both methods, all TFTs 8 are turned off and charged. It shifts to the accumulation state (see FIG. 6).

The processing time required for determining the start of irradiation in the first detection method is set as a basic cycle, and in the second detection method, the detection cycle of the radiation sensor 25 itself can be repeated a plurality of times during the basic cycle ( The result of multiple judgments is calculated), and only when it is judged that irradiation is started multiple times in a row, the second detection method comprehensively judges that irradiation is started, so that the radiation sensor 25 is sporadic. It is possible to deal with various noises.

Further, when it is determined by the second detection method that irradiation is started, if the state is immediately shifted to the charge accumulation state regardless of the state of the first method, for example, the first detection method (following the leakage data leak reading). ) When the reset process is in progress, a difference occurs between the reset end line and the unfinished line, and as a result, unevenness is likely to be superimposed on the radiation image information. Therefore, from the viewpoint of preventing unevenness, this embodiment The cycle of radiation irradiation start detection in the above is set to the basic cycle time (time including the leak data read time and the subsequent reset time) of the first detection method.

However, even if the start of radiation irradiation is detected by the first detection method, that is, the detection method based on the data from each radiation detection element 7 or the radiation detection pixel, vibration or the like is generated in the radiation image capturing device 1 as described above. As a result of the addition, the value of the leak data dleak or the like increases and becomes equal to or higher than the threshold dleak_th, and it is possible that the start of radiation irradiation is erroneously detected.

Therefore, in this unique configuration 3, the control means 22 of the radiation imaging apparatus 1 is tentatively first for a predetermined period from the time when the magnitude of the acceleration detected by the acceleration sensor 26 becomes equal to or greater than a predetermined threshold value. The detection method is configured so that the start of radiation irradiation is not detected even when the start of radiation irradiation is detected, such as when the value of the read leak data dleak increases and becomes equal to or higher than the threshold value dleak_th. It is possible.

Alternatively, the control means 22 of the radiation imaging apparatus 1 starts irradiation of radiation by the first detection method for a predetermined period from the time when the magnitude of the acceleration detected by the acceleration sensor 26 becomes equal to or greater than a predetermined threshold value. It is also possible to configure so that the detection process of is not performed.

The above-mentioned "time when the magnitude of the acceleration detected by the acceleration sensor 26 exceeds a predetermined threshold value" means, for example, the absolute value of the acceleration detected by the acceleration sensor 26 is calculated, and the absolute value is the predetermined threshold value. It may be the time when the above is reached, or a predetermined threshold value is set on the plus side and the minus side for the acceleration detected by the acceleration sensor 26, and the detected positive value acceleration is equal to or more than the predetermined threshold value on the plus side. It may be the time when the acceleration becomes equal to or less than the predetermined threshold value on the negative side.

With this configuration, when the magnitude of the acceleration detected by the acceleration sensor 26 exceeds a predetermined threshold value and a large acceleration occurs in the sensor panel SP, data from each radiation detection element 7 and radiation detection pixels Even if the start of radiation irradiation is detected by the detection method based on (the first detection method), it is not detected as the start of radiation irradiation, or the magnitude of the acceleration detected by the acceleration sensor 26 becomes equal to or greater than a predetermined threshold value. Since the detection process of the start of radiation irradiation by the first detection method is not performed for a predetermined period after that, it is accurate to erroneously detect the start of radiation irradiation due to the application of vibration or the like to the radiation imaging apparatus 1. It is possible to prevent radiation.

Further, even if the start of radiation irradiation cannot be detected by the first detection method for a predetermined period after the magnitude of the acceleration detected by the acceleration sensor 26 exceeds a predetermined threshold value as described above, the radiation is emitted. When the start of radiation irradiation is detected by the detection method (second detection method) based on the output value of the sensor 25, it is highly possible that the radiation irradiation is actually started.

Therefore, in this unique configuration 3, in such a case, the control means 22 of the radiation imaging apparatus 1 determines that the irradiation of radiation has started, turns the TFT 8 into an off state, and shifts the TFT 8 to a charge accumulation state. After that, the image data D is read out (see FIG. 6).

Since the first detection method described above is a detection method based on data from each radiation detection element 7 and radiation detection pixels, the acceleration sensor 26 determines whether or not each radiation detection element 7 or the like is accelerating. It is desirable to configure it to detect with. Therefore, for example, it is desirable that the acceleration sensor 26 is not attached to the inside of the housing 2 or the like, but is attached to the lower surface side or the like of the base 31 of the sensor panel SP as shown in FIG.

Then, in the research by the present inventors, if the acceleration sensor 26 is configured to be arranged at, for example, the center position of the sensor panel SP (see C in FIG. 21 described later), only one acceleration sensor 26 is arranged. Even in this case, it is known that the vibration (that is, acceleration) generated in the sensor panel SP can be accurately detected.

However, depending on the sensor panel SP (that is, depending on the radiation imaging device 1), for example, vibration due to an impact applied to the end of the housing 2 is transmitted through the buffer members 2B2 and 2C2 (see FIG. 17 and the like). It may take some time before the vibration is detected by the acceleration sensor 26 provided at the center position of the sensor panel SP.

Then, when it takes time for the vibration to be detected by the acceleration sensor 26, the value of the leak data dleak or the like increases due to the addition of the vibration or the like to the radiation imaging apparatus 1, and the timing and acceleration of the threshold dleak_th or more. There is a risk that the timing at which the sensor 26 detects vibration (that is, acceleration) will be different.

Then, when the timing is deviated as described above, the acceleration sensor 26 is still at the time when the start of radiation irradiation is detected by the detection method (first detection method) based on the data from each radiation detection element 7 and the radiation detection pixel. Since the magnitude of the acceleration detected by is not larger than a predetermined threshold value, there is a risk that the start of radiation irradiation may be erroneously detected. That is, there is a risk that the above-mentioned unique configuration 3 will not function.

Therefore, when there is a possibility as described above, the acceleration sensor 26 can be configured to be provided at the end portion on the lower surface side of the sensor panel SP. In this case, for example, the acceleration sensors 26 are provided at the four corners of the sensor panel SP, or as shown in FIG. 18, for example, a total of five acceleration sensors are provided at the four corners and the center position of the sensor panel SP. It is also possible to configure the 26 to be provided.

With this configuration, at least the acceleration sensor 26 provided at the position closest to the portion where the radiation imaging device 1 is subjected to impact, vibration, or the like increases the value of the leak data dleak or the like and becomes equal to or higher than the threshold value dleak_th. The output value increases at the same timing as when Therefore, it is possible to make the above-mentioned unique configuration 3 function properly.

[Required radiation sensor performance]
In this embodiment, in order to establish the above-mentioned unique configurations 1 to 3, the radiation sensor 25 in charge of the second detection method is output even when a disturbance such as vibration occurs as described above. A radiation sensor is used in which the noise does not increase and it is difficult to erroneously detect the start of radiation irradiation due to disturbance.

Further, as compared with the case shown in FIG. 19A, for example, as shown in FIG. 19B, the vertical fluctuation width of the amplifier output x in the sensor when noise, that is, irradiation of radiation is not detected. By using the radiation sensor 25 having a small size, it is possible to accurately detect the irradiated radiation.

That is, when the vertical swing width (that is, noise) of the amplifier output x is large as shown in FIG. 19A, the irradiation determination level for the amplifier output x shown in the upper part of the figure must be set to a high value. Therefore, in this state, if radiation is irradiated at the timing indicated by the arrow in the figure, the amplifier output x will be increased due to the irradiation of radiation with a small dose rate (that is, dose per unit time). Even if it rises, it may not exceed the irradiation judgment level.

Therefore, when radiation having such a small dose rate (that is, so-called weak radiation) is irradiated, the digital output d from the radiation sensor 25 is not transmitted as shown in the lower part of FIG. 19A, and eventually , It may not be possible to detect the start of radiation.

On the other hand, in the radiation sensor 25 having a small noise as shown in FIG. 19B, the irradiation determination level for the amplifier output x shown in the upper part of the figure is lowered by the amount of noise, that is, the vertical swing width of the amplifier output x is small. Is possible. Therefore, if radiation is irradiated at the timing indicated by the arrow in the figure, even if radiation with a small dose rate is irradiated, the set irradiation judgment level is low, so the amplifier output x will be increased due to the irradiation. It rises and becomes above the irradiation judgment level.

Therefore, if the radiation sensor 25 with low noise is used, the digital output d from the radiation sensor 25 can be accurately obtained even when the radiation with such a low dose rate is irradiated, as shown in the lower part of FIG. 19B. It is transmitted and it becomes possible to accurately detect the start of radiation irradiation.

[About the placement of radiation sensors]
Further, the radiation sensor 25 can be arranged by being directly attached to the lower surface of the base 31 as shown in FIG. 1, or by being attached to the lower surface of the PCB substrate 33 provided on the lower surface side of the base 31. is there. Further, in the configuration of the above embodiment, the dose reaching the radiation sensor 25 is attenuated to about 1/30 with respect to the irradiation dose. In order to increase the ratio of the dose reaching the radiation sensor 25 to the irradiation dose, the base 31 is partially provided with a recess to fix the radiation sensor 25, or the lead plate 42 corresponding to the radiation sensor 25 is partially provided. It may be cut out.

At that time, when only one radiation sensor 25 is provided, for example, as shown in FIG. 20, which is a view of the radiation imaging device 1 from above, the radiation sensor 25 is used as the detection unit P of the radiation imaging device 1. That is, they are arranged at the center position (that is, the diagonal intersection of the rectangular regions (see C in FIG. 21 to be described later)) of the plurality of radiation detection elements 7 on the sensor substrate 4 in a two-dimensionally arranged rectangular region. Ideally, it should be configured to do so.
The radiological technologist who performs the imaging can position the patient consciously that the radiation sensor 25 is provided in the center of the imageable area.

In the case of the radiation imaging device 1 having a size compatible with the CR cassette, the center position of the detection unit P is the region where the intensity is the weakest, so that reinforcement for improving the intensity (rigidity) of the radiation imaging device 1 In many cases, parts and parts that double as functional parts such as batteries and reinforcing parts are attached. Therefore, when only one radiation sensor 25 is provided, although not shown, the radiation sensor 25 can be configured to be arranged at a position deviated from the center position of the detection unit P by a predetermined distance in a predetermined direction. Is.
In that case, it may be difficult for the radiologist to perform positioning while being aware of the amount of deviation, and it is predicted that the start of irradiation of radiation cannot be detected.

On the other hand, if a plurality of radiation sensors 25 are arranged, for example, when radiation with a narrowed irradiation field is applied to the radiation imaging apparatus 1, only one radiation sensor 25 is provided in the radiation imaging apparatus 1. This is preferable because the probability that any of the radiation sensors 25 is irradiated with radiation is higher than in the case, and the possibility of detecting the start of radiation irradiation is increased.

When a plurality of radiation sensors 25 are arranged, for example, the following points need to be considered.

That is, depending on the patient, for example, the spine may be fixed or reinforced with a metal member. When the front of the chest or the front of the abdomen is photographed by radiographic imaging, the positional relationship between the patient and the radiographic imaging device 1 is usually adjusted so that the spine is located at the center of the detection unit P.

In addition, for example, when photographing the front of the lumbar region, the male genitalia may be covered with a shielding plate such as a lead plate to prevent radiation. In this case as well, since the shielding plate is basically located at the center of the lumbar region, the positional relationship is adjusted so that the shielding plate is located at the center of the detection unit P when photographing the front of the lumbar region. ..

In such a situation, when the radiation sensor 25 is arranged near the center of the detection unit P of the radiation imaging device 1, the irradiated radiation is emitted to a metal member of the spine of the patient, a shielding plate of the central part of the lumbar region, or the like. Is scattered or absorbed by. Therefore, the radiation reaching the radiation sensor 25 becomes weak, and there is a possibility that the radiation sensor 25 cannot accurately detect the start of irradiation.

Therefore, when a plurality of radiation sensors 25 are arranged, it is preferable to arrange the radiation sensors 25 at positions deviated from the center of the detection unit P. In this case, if the plurality of radiation sensors 25 are arranged together at positions deviated from the center of the detection unit P, all the radiation sensors 25 are shielded by a metal member or the like, and the start of radiation irradiation is accurate. There is a risk that it will not be detected.

Therefore, in order to arrange the plurality of radiation sensors 25 at positions separated from each other, for example, as shown in FIG. 21, the rectangular detection unit P is virtually arranged in four regions by two diagonal lines A. Considering each of the divided regions Pa, Pb, Pc, and Pd, it is possible to configure the radiation sensors 25 to be arranged in two regions that are not adjacent to each other.

Then, in that case, for example, as shown in FIG. 21, when the detection unit P of the radiation imaging apparatus 1 has a rectangular shape, the plurality of radiation sensors 25 are virtually divided into the rectangular detection unit P. Of the four regions, it can be configured to be arranged in two regions Pa and Pc including the short side of the rectangle, respectively. Although FIG. 21 and FIG. 22 described later show a case where two radiation sensors 25 are provided, three or more radiation sensors 25 may be provided.

For example, when the patient who is the subject is fat, the radiographic imaging apparatus 1 is arranged sideways (that is, in the vertical direction shown in FIG. 21, for example) when taking a front view of the chest, abdomen, waist, and the like. Imaging may be performed (with the radiation imaging apparatus 1 turned sideways).

At that time, if a plurality of radiation sensors 25 are arranged as described above, the irradiation field is not narrowed down in the arrangement direction (lateral direction) of the radiation sensors 25, so that both radiation sensors 25 can be used for radiation. It is possible to accurately detect the start of irradiation.

Further, for example, when the patient who is the subject is not fat, the radiographic image capturing apparatus 1 is often used in the vertical orientation shown in FIG. 21 for imaging. Then, in such a case, for example, if the spine of the patient is fixed with a metal member, or the central portion of the lumbar region is covered with a shielding plate, the plurality of radiation sensors 25 may use the metal member or the shielding. It may be shielded by a plate or the like, making it impossible to accurately detect the start of radiation irradiation.

Therefore, for example, as shown in FIG. 22, a plurality of radiation sensors 25 are provided in two rectangular regions having the same shape (that is, two vertically long regions in the case of FIG. 22) Pe and Pf. It is possible to configure the devices so that they are arranged at positions deviated from the center line B, not on the center line B that is virtually divided.

With this configuration, when the radiation imaging device 1 is arranged vertically for imaging, a plurality of radiations are emitted at left and right positions such as a metal member in the spine of the patient and a shielding plate in the center of the lumbar region. Since the sensors 25 are positioned respectively, it is possible to accurately prevent the radiation sensor 25 from being shielded by a metal member, a shielding plate, or the like. Then, any or all of the plurality of radiation sensors 25 can accurately detect the start of radiation irradiation.

In the case of the radiation imaging device 1 having a size compatible with the CR cassette, the radiologist may set the two radiation imaging devices 1 in each of the portrait / landscape settings for the subject, as described above. By arranging the two radiation sensors 25, it is possible to accurately detect the start of radiation irradiation with at least one radiation sensor 25 in any of the imaging.

Although FIGS. 21 and 22 show a case where a plurality of radiation sensors 25 are arranged at symmetrical positions with respect to the center C (see FIG. 21) of the detection unit P, it is not always necessary to configure the radiation sensors 25 in this way. It can be configured to be arranged at an appropriate position.

Further, in the above embodiment, as the first detection method, the start of radiation irradiation is mainly detected based on the read leak data dleak and the value calculated based on the leak data dleak (difference Δd (z) or the like). However, as described above, as the first detection method, for example, the detection methods described in the above-mentioned Patent Documents 6 to 8 and the like have been described. It is also possible to adopt it, and it goes without saying that the present invention is also applied when such a detection method is adopted as the first detection method.

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

For example, in the present embodiment, the first detection method for detecting the start of radiation irradiation based on the data from each radiation detection element 7 and the radiation detection pixel, and the radiation based on the output value of the radiation sensor 25. Both of the second detection methods for detecting the start of irradiation have always been enabled, but when the area to be imaged and the size of the area of interest to be imaged are known in advance (for example, the chest). In the case where it is known in advance from the shooting order information that the shooting is the trunk such as frontal shooting), the first detection method, which generally consumes a large amount of energy, is not used, and the latter second detection method is not used. By using only the detection method of, it is possible to suppress the consumption of the built-in battery.
In that case, when the radiation sensor determines that irradiation is started multiple times in a row, it is possible to immediately shift to the charge accumulation state (see FIG. 6), and it is possible to set a cycle shorter than the above-mentioned basic cycle. Become.

Further, it is also possible to provide the radiation imaging device 1 with another acceleration sensor, or to use the acceleration sensor 26 shown in FIGS. 17 and 18 so that the acceleration sensor can be used as a drop height detection sensor. Is. That is, the relationship between the height when the radiation imaging device 1 is dropped and the acceleration applied to the device is obtained in advance, and the acceleration detected by the drop height detection sensor is stored in the radiation imaging device 1. It is also possible to configure it so that it is possible to know from what height the radiation imaging apparatus 1 was dropped from the acceleration detected by the drop height detection sensor. This data (data related to the drop height) can be effectively used for maintenance and the like.

It can also be used in combination with a shock sensor for detecting drops and shocks during transportation after shipment from the factory. The shock sensor needs to be installed at a position that can be confirmed by a service person at the time of unpacking and installation, and unlike the above acceleration sensor, the lid member 2B or the lid member 2C that covers the opening is shown in FIG. It is preferable that it is provided in.

1 Radiation imaging device 2 Housing 3 Scintillator 4 Sensor board 5 Scanning line 6 Signal line 7 Radiation detection element 8 TFT (switch element)
15 Scanning drive means 17 Read circuit 22 Control means 25 Radiation sensor 26 Acceleration sensor 32 Electronic equipment 31 Base 34 Scintillator substrate 39 Conductive layer 42 Lead thin plate A Diagonal B Center line D Image data leak data (data)
dleak_st (z) Leak data statistics (values calculated based on leak data)
P Detection unit Pa to Pf Virtually divided area q Charge SP Sensor panel Δdmax Maximum value of difference (value calculated based on leak data)
Δd (z) difference (value calculated based on leak data)
ΣΔd integrated value (value calculated based on leak data)

Claims (4)

Multiple radiation detection elements that are arranged in two dimensions and generate electric charges when they receive radiation ,
A switching element switched to the ON state to pre SL in the radiation detection element to accumulate charges Ruofu state, or out-release pre Symbol radiation charges accumulated in the detection element,
Receiving and the ray Sensor release for outputting the radiation,
To detect the start of irradiation of radiology and control means for controlling the state of the switching element,
Before Symbol control means,
Of radiation by a first detection system for detecting the start of irradiation based pre SL on data from the data or the portion of the radiation detection pixels structure is changed for each radiation detection element, from each radiation detection element The detection of the start of irradiation is repeated at a predetermined cycle, and the detection of the start of radiation irradiation by the second detection method of detecting the start of radiation irradiation based on the output value of the radiation sensor is defined as the detection by the first detection method. Repeat in the same cycle,
Wherein when detecting the start of irradiation by the first detection method and the by any of the methods of the second detection system or both systems, radiation, characterized in that the switching element turned off Imaging device. The control means
In addition to repeating the detection of the start of radiation irradiation by the second detection method in the predetermined cycle, the detection is performed during the detection performed in the predetermined cycle.
The radiation imaging apparatus according to claim 1, wherein it is determined whether or not irradiation of radiation is started based on a plurality of output values obtained during the predetermined period. The radiation imaging apparatus according to claim 1 or 2, wherein the noise output by the radiation sensor when vibration occurs is smaller than the output of the radiation detection element or the radiation detection pixel. The control means according to any one of claims 1 to 3, which does not detect the start of radiation irradiation by the first detection method when photographing a predetermined imaging site or a predetermined region of interest. The radiographic imaging apparatus described.

Images