WO2012029403A1

WO2012029403A1 - Radiation imaging system, radiation imaging device, and computer-readable recording medium

Info

Publication number: WO2012029403A1
Application number: PCT/JP2011/065304
Authority: WO
Inventors: 直行西納; 直人岩切; 恭義大田; 晴康中津川
Original assignee: 富士フイルム株式会社
Priority date: 2010-08-30
Filing date: 2011-07-04
Publication date: 2012-03-08
Also published as: JP2012071105A

Abstract

Provided is a radiation imaging system, which is provided with: a radiation imaging device that is provided with a scintillator and a radiation detector; a detecting unit, which detects the temperature of the scintillator; and a control unit, which controls operations of the radiation imaging device. The control unit is provided with: a storage unit, which stores image pickup information that indicates an image pickup area and/or an image pickup state, wherein an image is permitted to be picked up corresponding to the temperature of the scintillator; and a specifying unit, which specifies the image pickup area and/or the image pickup state, corresponding to the detected temperature of the scintillator.

Description

Radiographic imaging system, radiographic imaging apparatus, and computer-readable recording medium

The present invention relates to a radiographic image capturing system, a radiographic image capturing device, and a computer-readable recording medium, and in particular, a radiographic image capturing system, a radiographic image capturing device, and a program for capturing a radiographic image indicated by radiation that has passed through an imaging target. The present invention relates to a computer-readable recording medium that stores.

In recent years, radiation detectors such as FPD (Flat Panel Detector) that can directly convert radiation into digital data by arranging a radiation sensitive layer on a TFT (Thin Film Transistor) active matrix substrate have been put into practical use. The radiographic imaging device using this radiation detector can see images immediately and can continuously capture radiographic images as compared with conventional radiographic imaging devices using X-ray film or imaging plate. There is an advantage that (moving image shooting) can also be performed.

Various types of radiation detectors of this type have been proposed. For example, radiation is once converted into light by a scintillator such as CsI: Tl or GOS (Gd2O2S: Tb), and the converted light is a photodiode or the like. There is an indirect conversion method in which the sensor unit converts the charges into charges. In the radiographic imaging apparatus, the electric charge accumulated in the radiation detector is read as an electric signal, and the read electric signal is amplified by an amplifier and then converted into digital data by an A / D (analog / digital) converter.

As a technique relating to this type of radiographic imaging apparatus, Japanese Patent Application Laid-Open No. 2009-28373 discloses a radiation conversion panel that detects radiation transmitted through a subject and converts it into radiation image information, and radiation detected by the radiation conversion panel. A memory for storing image information; at least the radiation conversion panel; a control unit for controlling the memory; a battery for supplying power to the radiation conversion panel, the memory and the control unit; and a temperature of at least the radiation conversion panel. Radiation imaging having a radiation detection cassette having a temperature sensor to detect, an imaging device that emits radiation toward the subject, and a host computer that controls the imaging device by exchanging information with the radiation detection cassette A control unit of the radiation detection cassette; Means for receiving information relating to shooting conditions from the host computer; capacity detecting means for detecting free space in the memory; remaining capacity detecting means for detecting the remaining battery capacity; capacity detecting means; There is disclosed a radiographic imaging system comprising: a determination means for determining permission / prohibition of use of the radiation detection cassette based on a result of the means and the temperature sensor and information on the received imaging condition.

Japanese Patent Application Laid-Open No. 2010-75671 discloses a radiation conversion panel that detects radiation transmitted through a subject and converts it into radiation image information, temperature detection means that detects the temperature of the radiation conversion panel, and based on the temperature. And a correction means for correcting at least one of sensitivity, dark current, density step and afterimage in the radiation conversion panel.

By the way, in the radiographic image capturing apparatus, since radiographic images are captured in a state where a region to be imaged is arranged on the imaging surface, a load is applied to the imaging surface during the imaging. Therefore, especially when the radiation detector is directly attached to the top plate constituting the imaging surface, or when the radiation detector is supported on the top plate, the radiation detector is also subjected to a load. Will be distorted.

On the other hand, in an indirect conversion type radiation detector, incident radiation is converted into light by a scintillator, and the scintillator is more likely to deteriorate due to distortion as the temperature increases.

Note that the deterioration of the scintillator is specifically the occurrence of cracks in the scintillator. When the crack is generated, as shown in FIGS. 22A to 22C as an example, the sensitivity is lowered, the photographed image is blurred, a defect image, or the like is caused depending on the generation position and size. At this time, the effect on the image quality is larger as the crack is generated near the sensor unit such as a photodiode that converts light converted by the scintillator into electric charge. As shown in FIG. 22A, when a crack occurs in the thickness direction on the surface irradiated with radiation, the sensitivity of the crack portion decreases because the thickness of the scintillator becomes thin. Becomes larger, resulting in an image defect. Also, as shown in FIG. 22B, when a crack occurs in the lateral direction on the radiation irradiation surface, if the crack portion is an air layer, the scattering of the radiation is increased by the air, leading to image blurring, and If the width is wide, radiation scattering also increases, and the difference in sensitivity with surrounding pixels increases, resulting in an image defect. Also, as shown in FIG. 22C, when a crack occurs in the vicinity of the sensor portion, the emitted light from the scintillator near the sensor portion is mainly received, so if a crack occurs in this portion, a defect image is obtained. Cheap.

In a conventional portable radiographic imaging device (hereinafter, also referred to as “electronic cassette”), as shown in FIG. 23A as an example, the scintillator is separated from the top plate in the casing of the electronic cassette. It was difficult to apply a load, and there was no need to consider scintillator distortion as a problem. On the other hand, in the future electronic cassette, as shown in FIG. 23B as an example, it is expected that a configuration in which a radiation detector is attached to the top plate is used for the purpose of thinning the electronic cassette, and in particular, CsI as a scintillator. When a substrate including the above is applied or a flexible substrate is employed as a substrate constituting the sensor unit, deterioration due to scintillator distortion due to a load becomes an important issue.

Therefore, in a radiographic imaging apparatus using an indirect conversion type radiation detector, when the scintillator temperature is relatively high, it is preferable not to capture radiographic images in order to suppress degradation of the scintillator. However, radiographic images may not be captured depending on the scintillator temperature.

On the other hand, although the technique disclosed in Japanese Patent Application Laid-Open No. 2009-28373 can also prohibit the use of the radiation detection cassette according to the temperature of the radiation conversion panel, in this case, the radiographic image is captured. I can't do it.

Note that, although the technique disclosed in the above-mentioned Japanese Patent Application Laid-Open No. 2010-75671 can capture a radiographic image, it cannot suppress degradation of the scintillator.

The present invention relates to a radiographic image capturing system, a radiographic image capturing apparatus, and a computer-readable recording medium storing a program capable of relaxing the limitation of radiographic image capturing according to the temperature of the scintillator while suppressing deterioration of the scintillator. provide.

According to the first aspect of the present invention, the radiation image includes a scintillator that converts incident radiation into light, and a radiation detector that includes a sensor unit that detects light converted by the scintillator, and is represented by the radiation. Imaging information indicating at least one of a radiographic imaging device that captures a radiographic image, a detection unit that detects the temperature of the scintillator, an imaging region that permits imaging by the radiographic imaging device according to the temperature of the scintillator, and an imaging state The radiographic imaging device based on the imaging information stored in the storage unit based on the temperature detected by the detection unit when the radiographic image is captured by the radiographic imaging device and the storage unit stored in advance A specific unit that specifies at least one of an imaging region and an imaging state that allow imaging by A controller for controlling the operation of the image capturing apparatus, the radiation image capturing system having provided.

According to the radiographic imaging system of the first aspect of the present invention, a radiographic image including a scintillator that converts incident radiation into light, and a radiation detector that includes a sensor unit that detects the light converted by the scintillator. A radiographic image indicated by the radiation is captured by the imaging device.

Here, in the present invention, imaging information indicating at least one of an imaging region and an imaging state in which imaging by the radiographic imaging device is permitted according to a temperature of the scintillator by a control device that controls the operation of the radiographic imaging device. Is stored in advance in the storage unit, and the imaging information stored in the storage unit based on the temperature of the scintillator detected by the detection unit when the radiographic image capturing apparatus captures a radiographic image by the specifying unit From this, at least one of an imaging region and an imaging state that allow imaging by the radiographic imaging device is specified.

As described above, according to the radiographic imaging system of the first aspect of the present invention, at least one of the imaging region and the imaging state that allows imaging predetermined according to the scintillator temperature based on the scintillator temperature. Therefore, by taking radiographic images by applying at least one of the specified imaging region and imaging state, it is possible to limit radiographic imaging according to the scintillator temperature while suppressing degradation of the scintillator. Can be relaxed.

In addition, according to the 2nd aspect of this invention, the said detection part may detect the temperature of the said scintillator based on the dark current which generate | occur | produces in the said sensor part. Thereby, compared with the case where a temperature sensor is used as the said detection part, cost can be reduced more.

Further, according to the third aspect of the present invention, the control device may further include a warning unit that issues a warning when the identification result by the identification unit does not match an actual photographing situation. Thereby, the convenience for a user can be improved more.

According to the fourth aspect of the present invention, in the case where the specifying unit specifies at least the shooting state, and the control device does not match the shooting state specified by the specifying unit with the actual shooting state. And when there exists an alternative imaging | photography state, you may further provide the presentation part which shows the said alternative imaging | photography state. Thereby, the convenience for a user can be improved more. The presentation by the presenting unit includes presentation by visual display by a display device, presentation by audible display by an audio device, and presentation by permanent visual display by an image forming device.

Also, according to the fifth aspect of the present invention, the shooting state may include shooting in a supine position and shooting in a standing position. Thereby, in the form which performs these imaging | photography, the restriction | limiting of imaging | photography of the radiographic image according to the temperature of a scintillator can be eased, suppressing deterioration of a scintillator.

In the present invention, in a standing position, it is difficult to apply a load regardless of whether the image is taken on a photographing stand or held with a hand. Therefore, the radiation image photographing apparatus is assumed regardless of the scintillator temperature. It is good also as what permits all imaging | photography. In addition, in the case of photographing in a supine position, the scintillator temperature is also set on the condition that the radiographic imaging device is held by a holding unit that can receive a load from the radiographing object instead of the radiographic imaging device. Regardless of the case, it is possible to allow all imaging assumed in the radiographic imaging apparatus. Furthermore, even in a case where the radiographic imaging device is not held by the holding unit in imaging in a recumbent position, an externally strengthened casing (so-called jacket) that can receive a load from an imaging target instead of the radiographic imaging device And the radiographic imaging device may be integrated, and all imaging assumed in the radiographic imaging device may be allowed regardless of the scintillator temperature.

Further, according to the sixth aspect of the present invention, the sensor unit may include an organic photoelectric conversion material that generates charges when receiving light generated by the scintillator. Thereby, the impact resistance of a radiographic imaging apparatus can be improved.

Further, according to the seventh aspect of the present invention, the radiation detector is directly applied to a surface opposite to the surface on which the radiation is incident on the top plate having a transmission surface through which the radiation transmitted through the subject is transmitted. It may be attached. Thereby, the impact resistance of a radiographic imaging apparatus can be improved.

Here, according to the seventh aspect of the present invention, the top plate may be made of a material containing a reinforcing fiber resin. Thereby, compared with the case where a top plate is comprised with a carbon single-piece | unit etc., the intensity | strength of a top plate can be made high.

Particularly, in the present invention, the reinforcing fiber resin may be a carbon fiber reinforced plastic. As a result, it is possible to increase the thermal conductivity of the top plate as compared with the case where the top plate is made of carbon alone, and as a result, image unevenness due to temperature unevenness of the radiation image obtained by the radiation detector is reduced. Can be suppressed.

By the way, the deterioration (crack) of the scintillator is particularly problematic in an aspect in which the scintillator includes CsI and the radiation detector is in a so-called surface reading system in which radiation is incident in the order of the sensor unit and the scintillator.

So, according to the 8th aspect of this invention, in the 7th aspect, the said scintillator is comprised including cesium iodide, and the said radiation detector injects the said radiation in order of the said sensor part and the said scintillator. It may be laminated as described. Thereby, also in the said aspect, the effect of this invention can be acquired.

Further, according to the ninth aspect of the present invention, in the seventh or eighth aspect, the radiation detector may be attached to the top plate so as to be separable. Thereby, a housing | casing can be exchanged efficiently.

According to a tenth aspect of the present invention, in any one of the seventh to ninth aspects, the radiographic imaging device has an internal space formed between the radiation detector and the top plate. An adhesive member that adheres the radiation detector to the top plate, and a ventilation portion that communicates the internal space and the outside and prevents foreign matter from entering the internal space from the outside. Also good.

According to the present invention, since the radiation detector is bonded to the top plate so that an internal space is formed between the radiation detector and the top plate using the adhesive member, the contact of the adhesive member to the radiation detector and the top plate is achieved. Even if air remains on the surface, the remaining air can be released to the internal space. In addition, since the internal space communicates with the outside through the ventilation portion, the pressure in the internal space and the external atmospheric pressure can be kept constant even when the atmospheric pressure changes. Therefore, it can prevent that the adhesiveness of the radiation detector with respect to a top plate falls by atmospheric pressure change.

Further, since the ventilation portion prevents foreign matters from entering the internal space from the outside, it is possible to eliminate the concern that foreign matters such as metal pieces that absorb radiation enter the internal space and are displayed in the radiation image. . Accordingly, it is possible to suppress the contamination of foreign matters that leads to the deterioration of the quality of the radiation image.

In particular, according to the tenth aspect of the present invention, the ventilation portion may be a communication path formed in the adhesive member and communicating in a state of bending the internal space and the outside.

According to the present invention, since the communication path is bent, it is possible to prevent the foreign matter from entering the internal space even when foreign matter flows into the communication path from the outside together with air. This is because the mass of the foreign matter is larger than the mass of air, so that the foreign matter cannot follow the flow of air flowing through the bent portion of the communication path. Further, since the communication path is formed in the adhesive member, the foreign matter is likely to adhere to the wall surface of the communication path. Accordingly, the foreign matter that can no longer follow the air flow at the bent portion of the communication passage is reliably captured by the wall surface of the communication passage having adhesiveness. As a result, it is possible to more reliably prevent foreign matter from entering the internal space.

Furthermore, according to the eleventh aspect of the present invention, in any one of the seventh to tenth aspects, the top plate may constitute a part of a housing that houses the radiation detector. Thereby, compared with the case where a top plate is comprised separately from a housing | casing, a top plate can be comprised more simply.

Further, according to the twelfth aspect of the present invention, in any one of the first to seventh aspects, the scintillator may include cesium iodide as in the twelfth aspect. As a result, the occurrence of contact between the columnar crystals of cesium iodide due to the load can be prevented in advance, and the deterioration of the scintillator can be suppressed more effectively.

According to the thirteenth aspect of the present invention, a scintillator that converts incident radiation into light, a radiation detector that includes a sensor unit that detects light converted by the scintillator, and detection that detects the temperature of the scintillator A radiographic image by the radiation detector, a storage unit in which imaging information indicating at least one of an imaging region and an imaging state in which imaging by the radiation detector is allowed according to the temperature of the scintillator is stored in advance, and the radiation detector Based on the temperature detected by the detection unit when performing, a specifying unit that specifies at least one of an imaging region and an imaging state that allows imaging by the radiation detector from the imaging information stored in the storage unit, A radiographic image capturing apparatus is provided.

Therefore, according to the present invention, since it operates in the same manner as the first aspect of the invention, as in the first aspect of the invention, it is possible to capture radiographic images according to the temperature of the scintillator while suppressing degradation of the scintillator. Limits can be relaxed.

According to the fourteenth aspect, the radiation detector includes a scintillator that converts incident radiation into light and a sensor unit that detects light converted by the scintillator, and captures a radiation image indicated by the radiation. A detection unit that detects the temperature of the scintillator in a radiographic imaging device based on a dark current generated in the sensor unit, and a temperature that is detected by the detection unit when radiographic imaging is performed by the radiographic imaging device Based on the above, there is provided a computer readable medium storing a program for functioning as a specifying unit that specifies at least one of an imaging region and an imaging state that allow imaging by the radiographic imaging device.

Therefore, according to the present invention, since the computer can be operated in the same manner as the first aspect of the invention, the temperature of the scintillator can be adjusted while suppressing the deterioration of the scintillator as in the first aspect of the invention. The restriction of radiographic image capturing can be relaxed.

According to the present invention, it is possible to obtain an effect that it is possible to relax restrictions on radiographic imaging according to the temperature of the scintillator while suppressing deterioration of the scintillator.

It is a block diagram which shows the structure of the radiation information system which concerns on embodiment. It is a side view which shows an example of the arrangement | positioning state of each apparatus in the radiography room of the radiographic imaging system which concerns on embodiment. It is a cross-sectional schematic diagram which shows schematic structure of the 3 pixel part of the radiation detector which concerns on embodiment. It is the cross-sectional side view which showed schematically the structure of the signal output part of 1 pixel part of the radiation detector which concerns on embodiment. It is a schematic plan view which shows the structure of the radiation detector which concerns on embodiment. It is a perspective view which shows the structure of the electronic cassette concerning embodiment. It is a schematic plan view which shows the structure of the scintillator which concerns on embodiment. It is a section side view showing the composition of the electronic cassette concerning an embodiment. It is a cross-sectional bottom view which shows the internal structure of the housing | casing of the electronic cassette concerning embodiment. It is a partially expanded sectional bottom view which shows the internal structure of the housing | casing of the electronic cassette concerning embodiment. It is explanatory drawing which shows the state which peels a radiation detector from a top plate in the electronic cassette which concerns on embodiment. It is a block diagram which shows the principal part structure of the electrical system of the radiographic imaging system which concerns on embodiment. It is a schematic diagram which shows the structure of the imaging | photography information which concerns on embodiment. It is a flowchart which shows the flow of a process of the radiographic imaging process program which concerns on 1st Embodiment. It is the schematic which shows an example of the initial stage information input screen which concerns on embodiment. It is the schematic which shows an example of the warning screen which concerns on embodiment. It is a flowchart which shows the flow of a process of the temperature information transmission process program which concerns on 1st Embodiment. It is a flowchart which shows the flow of a process of the radiographic imaging process program which concerns on 2nd Embodiment. It is a flowchart which shows the flow of a process of the dark current information transmission process program which concerns on 2nd Embodiment. It is a cross-sectional side view for demonstrating the surface reading system and back surface reading system of the radiation to a radiation detector. It is a partially expanded sectional bottom view which shows the modification of the internal structure of the housing | casing of the electronic cassette concerning embodiment. It is a schematic diagram (schematic side view) used for description of a subject. It is a schematic diagram (schematic side view) used for description of a subject. It is a schematic diagram (schematic side view) used for description of a subject. It is a schematic diagram (schematic side view) used for description of a subject. It is a schematic diagram (schematic side view) used for description of a subject. It is a graph which shows an example of the sensitivity characteristic of various materials. It is a graph which shows an example of the sensitivity characteristic of various materials.

Hereinafter, embodiments for carrying out the present invention will be described in detail with reference to the drawings. Here, a description will be given of an example in which the present invention is applied to a radiation information system that is a system for comprehensively managing information handled in a radiology department in a hospital.

[First Embodiment]
First, the configuration of a radiation information system (hereinafter referred to as “RIS” (Radiology Information System)) 100 according to the present embodiment will be described with reference to FIG.

The RIS 100 is a system for performing information management such as medical appointment reservation and diagnosis record in the radiology department, and constitutes a part of a hospital information system (hereinafter referred to as “HIS” (Hospital Information System)). .

The RIS 100 includes a plurality of radiography requesting terminal devices (hereinafter referred to as “terminal devices”) 140, a RIS server 150, and a radiographic imaging system (or an operating room) installed in a radiographic room (or operating room) in a hospital. (Hereinafter referred to as “imaging system”) 104, which are connected to an in-hospital network 102 composed of a wired or wireless LAN (Local Area Network) or the like. The RIS 100 constitutes a part of the HIS provided in the same hospital, and an HIS server (not shown) for managing the entire HIS is also connected to the in-hospital network 102.

The terminal device 140 is used by doctors and radiographers to input and browse diagnostic information and facility reservations, and radiographic image capturing requests and imaging reservations are also performed via the terminal device 140. Each terminal device 140 includes a personal computer having a display device, and can communicate with the RIS server 150 via the hospital network 102.

On the other hand, the RIS server 150 receives an imaging request from each terminal device 140 and manages a radiographic imaging schedule in the imaging system 104, and includes a database 150A.

Database 150A includes patient (subject) attribute information (name, sex, date of birth, age, blood type, weight, patient ID (Identification), etc.), medical history, medical history, radiation images taken in the past, etc. Information regarding the patient, information regarding the electronic cassette 40 used in the imaging system 104, such as an identification number (ID information), model, size, sensitivity, start date of use, number of times of use, etc., and the electronic cassette 40 It includes the environment information which shows the environment which takes a radiographic image using, ie, the environment (for example, a radiography room, an operating room, etc.) which uses electronic cassette 40.

The imaging system 104 captures a radiographic image by an operation of a doctor or a radiographer according to an instruction from the RIS server 150. The imaging system 104 includes a radiation generator 120 that irradiates a subject with radiation X (see also FIG. 6) that has been dosed according to the exposure conditions from a radiation source 121 (see also FIG. 2), and a subject. An electronic cassette having a built-in radiation detector 20 (see also FIG. 6) that generates radiation by absorbing the radiation X transmitted through the imaging region of the person and generates image information indicating a radiation image based on the amount of the generated charge. 40, a cradle 130 for charging a battery built in the electronic cassette 40, and a console 110 for controlling the electronic cassette 40 and the radiation generator 120.

The console 110 acquires various types of information included in the database 150A from the RIS server 150, stores them in the HDD 116 (see FIG. 12) described later, and uses the information as necessary to use the electronic cassette 40 and the radiation generator 120. Control.

FIG. 2 shows an example of the arrangement state of each device in the radiation imaging room 180 of the imaging system 104 according to the present embodiment.

As shown in FIG. 2, the radiation imaging room 180 includes a standing table 160 used when performing radiography in a standing position and a prone table 164 used when performing radiography in a lying position. The space in front of the standing stand 160 is set as a photographing position 170 of the subject when performing radiography in the standing position, and the space above the supine stand 164 is when performing radiography in the prone position. The imaging position 172 of the subject.

The standing stand 160 is provided with a holding unit 162 that holds the electronic cassette 40, and the electronic cassette 40 is held by the holding unit 162 when a radiographic image is taken in the standing position. Similarly, the holding table 164 is provided with a holding unit 166 that holds the electronic cassette 40, and the electronic cassette 40 is held by the holding unit 166 when a radiographic image is taken in the lying position.

Further, in the radiation imaging room 180, the radiation source 121 is placed around a horizontal axis (see FIG. 5) in order to enable radiation imaging in a standing position and radiation imaging in a lying position by radiation from a single radiation source 121. 2 is provided, and a support moving mechanism 124 is provided which can be rotated in the vertical direction (arrow b direction in FIG. 2) and can be moved in the horizontal direction (arrow c direction in FIG. 2). It has been. Here, the support moving mechanism 124 includes a drive source that rotates the radiation source 121 around a horizontal axis, a drive source that moves the radiation source 121 in the vertical direction, and a drive source that moves the radiation source 121 in the horizontal direction. Each is provided (not shown).

On the other hand, the cradle 130 is formed with an accommodating portion 130A that can accommodate the electronic cassette 40.

When the electronic cassette 40 is not in use, the built-in battery is charged in a state of being housed in the housing portion 130A of the cradle 130. When a radiographic image is taken, the electronic cassette 40 is taken out from the cradle 130 by a radiographer or the like, and the photographing posture is established. If it is in the upright position, it is held in the holding part 162 of the standing base 160, and if it is in the upright position, it is held in the holding part 166 of the standing base 164.

Here, in the imaging system 104 according to the present embodiment, various types of information are transmitted and received between the radiation generator 120 and the console 110 and between the electronic cassette 40 and the console 110 by wireless communication.

The electronic cassette 40 is not used only in a state where it is held by the holding part 162 of the standing base 160 or the holding part 166 of the prone base 164. When photographing, it can be used in a state where it is not held by the holding unit.

Next, the configuration of the radiation detector 20 according to the present embodiment will be described. FIG. 3 is a schematic cross-sectional view schematically showing the configuration of the three pixel portions of the radiation detector 20 according to the present exemplary embodiment.

As shown in FIG. 3, in the radiation detector 20 according to the present exemplary embodiment, the signal output unit 14, the sensor unit 13, and the scintillator 8 are sequentially stacked on the insulating substrate 1. The pixel unit is configured by the sensor unit 13. A plurality of pixel units are arranged on the substrate 1, and the signal output unit 14 and the sensor unit 13 in each pixel unit are configured to overlap each other.

The scintillator 8 is formed on the sensor unit 13 via the transparent insulating film 7, and forms a phosphor that emits light by converting radiation incident from above (opposite side of the substrate 1) or from below into light. It is a thing. Providing such a scintillator 8 absorbs the radiation transmitted through the subject and emits light.

The wavelength range of light emitted by the scintillator 8 is preferably the visible light range (wavelength 360 nm to 830 nm), and in order to enable monochrome imaging by the radiation detector 20, the wavelength range of green is included. Is more preferable.

Specifically, the phosphor used in the scintillator 8 preferably contains cesium iodide (CsI) when imaging using X-rays as radiation, and has an emission spectrum of 420 nm to 700 nm upon X-ray irradiation. It is particularly preferable to use CsI (Tl) (cesium iodide with thallium added). Note that the emission peak wavelength of CsI (Tl) in the visible light region is 565 nm.

The scintillator 8 may be formed by vapor deposition on a vapor deposition substrate, for example, when it is going to be formed with columnar crystals such as CsI (Tl). When the scintillator 8 is formed by vapor deposition as described above, an Al plate is often used as the vapor deposition substrate in terms of X-ray transmittance and cost, but is not limited thereto. When GOS is used as the scintillator 8, the scintillator 8 may be formed by applying GOS to the surface of the TFT substrate 30 described later without using a vapor deposition substrate.

The sensor unit 13 includes an upper electrode 6, a lower electrode 2, and a photoelectric conversion film 4 disposed between the upper and lower electrodes. The photoelectric conversion film 4 absorbs light emitted from the scintillator 8 and generates charges. It is composed of an organic photoelectric conversion material.

Since it is necessary for the upper electrode 6 to cause the light generated by the scintillator 8 to be incident on the photoelectric conversion film 4, it is preferable that the upper electrode 6 be made of a conductive material that is transparent at least with respect to the emission wavelength of the scintillator 8. It is preferable to use a transparent conductive oxide (TCO) having a high transmittance for visible light and a small resistance value. Although a metal thin film such as Au can be used as the upper electrode 6, TCO is preferable because it tends to increase the resistance value when it is desired to obtain a transmittance of 90% or more. For example, ITO, IZO, AZO, FTO, SnO ₂ , TiO ₂ , ZnO _{2 and the} like can be preferably used, and ITO is most preferable from the viewpoint of process simplicity, low resistance, and transparency. Note that the upper electrode 6 may have a single configuration common to all the pixel portions, or may be divided for each pixel portion.

The photoelectric conversion film 4 contains an organic photoelectric conversion material, absorbs light emitted from the scintillator 8, and generates electric charges according to the absorbed light. In this way, the photoelectric conversion film 4 containing an organic photoelectric conversion material has a sharp absorption spectrum in the visible range, and electromagnetic waves other than light emitted by the scintillator 8 are hardly absorbed by the photoelectric conversion film 4. The noise generated by the radiation such as being absorbed by the photoelectric conversion film 4 can be effectively suppressed.

The organic photoelectric conversion material constituting the photoelectric conversion film 4 is preferably such that its absorption peak wavelength is closer to the emission peak wavelength of the scintillator 8 in order to absorb light emitted by the scintillator 8 most efficiently. Ideally, the absorption peak wavelength of the organic photoelectric conversion material matches the emission peak wavelength of the scintillator 8, but if the difference between the two is small, the light emitted from the scintillator 8 can be sufficiently absorbed. . Specifically, the difference between the absorption peak wavelength of the organic photoelectric conversion material and the emission peak wavelength with respect to the radiation of the scintillator 8 is preferably within 10 nm, and more preferably within 5 nm.

Examples of the organic photoelectric conversion material that can satisfy such conditions include quinacridone organic compounds and phthalocyanine organic compounds. For example, since the absorption peak wavelength of quinacridone in the visible region is 560 nm, if quinacridone is used as the organic photoelectric conversion material and CsI (Tl) is used as the material of the scintillator 8, the difference in the peak wavelength can be within 5 nm. Thus, the amount of charge generated in the photoelectric conversion film 4 can be substantially maximized.

Next, the photoelectric conversion film 4 applicable to the radiation detector 20 according to the present embodiment will be specifically described.

The electromagnetic wave absorption / photoelectric conversion site in the radiation detector 20 according to the present embodiment is configured by an organic layer including a pair of

electrodes

2 and 6 and an organic photoelectric conversion film 4 sandwiched between the

electrodes

2 and 6. be able to. More specifically, this organic layer is a part that absorbs electromagnetic waves, a photoelectric conversion part, an electron transport part, a hole transport part, an electron blocking part, a hole blocking part, a crystallization preventing part, an electrode, and an interlayer contact improvement. It can be formed by stacking or mixing parts.

The organic layer preferably contains an organic p-type compound or an organic n-type compound.

An organic p-type semiconductor (compound) is a donor organic semiconductor (compound) typified by a hole-transporting organic compound and refers to an organic compound having a property of easily donating electrons. More specifically, an organic compound having a smaller ionization potential when two organic materials are used in contact with each other. Accordingly, any organic compound can be used as the donor organic compound as long as it is an electron-donating organic compound.

An organic n-type semiconductor (compound) is an acceptor organic semiconductor (compound) typified by an electron-transporting organic compound and refers to an organic compound having a property of easily accepting electrons. More specifically, the organic compound having the higher electron affinity when two organic compounds are used in contact with each other. Accordingly, as the acceptor organic compound, any organic compound can be used as long as it is an electron-accepting organic compound.

The materials applicable as the organic p-type semiconductor and the organic n-type semiconductor and the configuration of the photoelectric conversion film 4 are described in detail in Japanese Patent Application Laid-Open No. 2009-32854, and thus the description thereof is omitted. The photoelectric conversion film 4 may be formed by further containing fullerenes or carbon nanotubes.

The thickness of the photoelectric conversion film 4 is preferably as large as possible in terms of absorbing light from the scintillator 8. However, when the thickness is more than a certain level, the photoelectric conversion film 4 is generated in the photoelectric conversion film 4 by a bias voltage applied from both ends of the photoelectric conversion film 4. Since electric field strength is reduced and charges cannot be collected, the thickness is preferably 30 nm to 300 nm, more preferably 50 nm to 250 nm, and particularly preferably 80 nm to 200 nm.

In the radiation detector 20 shown in FIG. 3, the photoelectric conversion film 4 has a single-sheet configuration common to all the pixel portions, but may be divided for each pixel portion.

The lower electrode 2 is a thin film divided for each pixel portion. The lower electrode 2 can be made of a transparent or opaque conductive material, and aluminum, silver, or the like can be suitably used.

The thickness of the lower electrode 2 can be, for example, 30 nm or more and 300 nm or less.

In the sensor unit 13, by applying a predetermined bias voltage between the upper electrode 6 and the lower electrode 2, one of electric charges (holes, electrons) generated in the photoelectric conversion film 4 is moved to the upper electrode 6. The other can be moved to the lower electrode 2. In the radiation detector 20 of the present embodiment, a wiring is connected to the upper electrode 6, and a bias voltage is applied to the upper electrode 6 through this wiring. In addition, the polarity of the bias voltage is determined so that electrons generated in the photoelectric conversion film 4 move to the upper electrode 6 and holes move to the lower electrode 2, but this polarity is reversed. May be.

The sensor unit 13 constituting each pixel unit only needs to include at least the lower electrode 2, the photoelectric conversion film 4, and the upper electrode 6. In order to suppress an increase in dark current, the electron blocking film 3 and hole blocking are performed. It is preferable to provide at least one of the films 5, and it is more preferable to provide both.

The electron blocking film 3 can be provided between the lower electrode 2 and the photoelectric conversion film 4. When a bias voltage is applied between the lower electrode 2 and the upper electrode 6, electrons are transferred from the lower electrode 2 to the photoelectric conversion film 4. It is possible to suppress the dark current from increasing due to the injection of.

An electron donating organic material can be used for the electron blocking film 3.

The material actually used for the electron blocking film 3 may be selected according to the material of the adjacent electrode, the material of the adjacent photoelectric conversion film 4 and the like, and 1.3 eV or more from the work function (Wf) of the material of the adjacent electrode. Those having a large electron affinity (Ea) and an Ip equivalent to or smaller than the ionization potential (Ip) of the material of the adjacent photoelectric conversion film 4 are preferable. The material applicable as the electron donating organic material is described in detail in Japanese Patent Application Laid-Open No. 2009-32854, and thus the description thereof is omitted.

The thickness of the electron blocking film 3 is preferably 10 nm or more and 200 nm or less, more preferably 30 nm or more and 150 nm or less, and particularly preferably, in order to surely exhibit the dark current suppressing effect and prevent a decrease in photoelectric conversion efficiency of the sensor unit 13. It is 50 nm or more and 100 nm or less.

The hole blocking film 5 can be provided between the photoelectric conversion film 4 and the upper electrode 6. When a bias voltage is applied between the lower electrode 2 and the upper electrode 6, the hole blocking film 5 is transferred from the upper electrode 6 to the photoelectric conversion film 4. It is possible to suppress the increase in dark current due to the injection of holes.

An electron-accepting organic material can be used for the hole blocking film 5.

The thickness of the hole blocking film 5 is preferably 10 nm or more and 200 nm or less, more preferably 30 nm or more and 150 nm or less, and particularly preferably, in order to surely exhibit the dark current suppressing effect and prevent a decrease in photoelectric conversion efficiency of the sensor unit 13. Is from 50 nm to 100 nm.

The material actually used for the hole blocking film 5 may be selected according to the material of the adjacent electrode, the material of the adjacent photoelectric conversion film 4 and the like, and 1.3 eV from the work function (Wf) of the material of the adjacent electrode. As described above, it is preferable that the ionization potential (Ip) is large and that the Ea is equal to or larger than the electron affinity (Ea) of the material of the adjacent photoelectric conversion film 4. Since the material applicable as the electron-accepting organic material is described in detail in Japanese Patent Application Laid-Open No. 2009-32854, description thereof is omitted.

In addition, when a bias voltage is set so that holes move to the upper electrode 6 and electrons move to the lower electrode 2 among the charges generated in the photoelectric conversion film 4, the electron blocking film 3 and the hole blocking are set. The position of the film 5 may be reversed. Moreover, it is not necessary to provide both the electron blocking film 3 and the hole blocking film 5. If either one is provided, a certain degree of dark current suppressing effect can be obtained.

A signal output unit 14 is formed on the surface of the substrate 1 below the lower electrode 2 of each pixel unit. FIG. 4 schematically shows the configuration of the signal output unit 14.

As shown in FIG. 4, the signal output unit 14 according to the present embodiment corresponds to the lower electrode 2, the capacitor 9 that accumulates the charges moved to the lower electrode 2, and the electric charges accumulated in the capacitor 9 A field effect thin film transistor (Thin Film Transistor, hereinafter simply referred to as a thin film transistor) 10 is formed which is converted into a signal and output. The region in which the capacitor 9 and the thin film transistor 10 are formed has a portion that overlaps the lower electrode 2 in a plan view. With such a configuration, the signal output unit 14 and the sensor unit 13 in each pixel unit are connected to each other. There will be overlap in the thickness direction. In order to minimize the plane area of the radiation detector 20 (pixel portion), it is desirable that the region where the capacitor 9 and the thin film transistor 10 are formed is completely covered by the lower electrode 2.

The capacitor 9 is electrically connected to the corresponding lower electrode 2 via a wiring made of a conductive material penetrating an insulating film 11 provided between the substrate 1 and the lower electrode 2. Thereby, the electric charge collected by the lower electrode 2 can be moved to the capacitor 9.

In the thin film transistor 10, a gate electrode 15, a gate insulating film 16, and an active layer (channel layer) 17 are stacked, and a source electrode 18 and a drain electrode 19 are formed on the active layer 17 at a predetermined interval. . The active layer 17 can be formed of, for example, amorphous silicon, amorphous oxide, organic semiconductor material, carbon nanotube, or the like. In addition, the material which comprises the active layer 17 is not limited to these.

The amorphous oxide that can form the active layer 17 is preferably an oxide containing at least one of In, Ga, and Zn (for example, In—O-based), and at least 2 of In, Ga, and Zn. (Eg, In—Zn—O, In—Ga—O, and Ga—Zn—O) are more preferable, and oxides including In, Ga, and Zn are particularly preferable. As the In—Ga—Zn—O-based amorphous oxide, an amorphous oxide whose composition in a crystalline state is represented by InGaO ₃ (ZnO) _m (m is a natural number less than 6) is preferable, and in particular, InGaZnO. ₄ is more preferable. In addition, the amorphous oxide which can comprise the active layer 17 is not limited to these.

Examples of the organic semiconductor material that can form the active layer 17 include, but are not limited to, phthalocyanine compounds, pentacene, vanadyl phthalocyanine, and the like. Note that the configuration of the phthalocyanine compound is described in detail in JP-A-2009-212389, and thus the description thereof is omitted.

If the active layer 17 of the thin film transistor 10 is formed of an amorphous oxide, an organic semiconductor material, or a carbon nanotube, it will not absorb radiation such as X-rays, or even if it absorbs it, it will remain in a very small amount. Generation of noise in the portion 14 can be effectively suppressed.

Further, when the active layer 17 is formed of carbon nanotubes, the switching speed of the thin film transistor 10 can be increased, and the thin film transistor 10 having a low degree of light absorption in the visible light region can be formed. In addition, when the active layer 17 is formed of carbon nanotubes, the performance of the thin film transistor 10 is remarkably deteriorated only by mixing a very small amount of metallic impurities into the active layer 17, so that extremely high purity carbon nanotubes can be obtained by centrifugation or the like. It is necessary to form by separating and extracting.

Here, any of the amorphous oxides, organic semiconductor materials, carbon nanotubes constituting the active layer 17 of the thin film transistor 10 and organic photoelectric conversion materials constituting the photoelectric conversion film 4 can be formed at a low temperature. . Therefore, the substrate 1 is not limited to a substrate having high heat resistance such as a semiconductor substrate, a quartz substrate, and a glass substrate, and a flexible substrate such as plastic, aramid, or bionanofiber can also be used. Specifically, flexible materials such as polyesters such as polyethylene terephthalate, polybutylene phthalate, polyethylene naphthalate, polystyrene, polycarbonate, polyethersulfone, polyarylate, polyimide, polycycloolefin, norbornene resin, poly (chlorotrifluoroethylene), etc. A conductive substrate can be used. If such a plastic flexible substrate is used, it is possible to reduce the weight, which is advantageous for carrying around, for example.

In addition, the substrate 1 is provided with an insulating layer for ensuring insulation, a gas barrier layer for preventing permeation of moisture and oxygen, an undercoat layer for improving flatness or adhesion to electrodes, and the like. May be.

On the other hand, since aramid can be applied at a high temperature process of 200 ° C. or higher, the transparent electrode material can be cured at high temperature to reduce the resistance, and can also be used for automatic mounting of driver ICs including a solder reflow process. Aramid has a thermal expansion coefficient close to that of ITO (Indium Tin Oxide) or glass substrate, so there is little warping after manufacturing and it is difficult to crack. In addition, aramid can form a substrate thinner than a glass substrate or the like. The substrate may be formed by laminating an ultrathin glass substrate and aramid.

In addition, the bionanofiber is a composite of a cellulose microfibril bundle (bacterial cellulose) produced by bacteria (Acetobacter Xylinum) and a transparent resin. The cellulose microfibril bundle has a width of 50 nm and a size of 1/10 of the visible light wavelength, and has high strength, high elasticity, and low thermal expansion. By impregnating and curing a transparent resin such as acrylic resin or epoxy resin in bacterial cellulose, a bio-nanofiber having a light transmittance of about 90% at a wavelength of 500 nm can be obtained while containing 60 to 70% of the fiber. Bionanofiber has a low coefficient of thermal expansion (3-7ppm) comparable to silicon crystals, and is as strong as steel (460MPa), highly elastic (30GPa), and flexible. The substrate 1 can be formed thinly.

In the present embodiment, the TFT substrate 30 is formed on the substrate 1 by sequentially forming the signal output unit 14, the sensor unit 13, and the transparent insulating film 7, and the light-absorbing adhesive resin is formed on the TFT substrate 30. The radiation detector 20 is formed by pasting the scintillator 8 using, for example.

As shown in FIG. 5, the TFT substrate 30 includes a pixel unit 32 including the sensor unit 13, the capacitor 9, and the thin film transistor 10 described above in a certain direction (the row direction in FIG. 5) and the certain direction. A plurality of two-dimensional shapes are provided in the intersecting direction (column direction in FIG. 5).

Further, the radiation detector 20 extends in the predetermined direction (row direction), and extends in the intersecting direction (column direction) with a plurality of gate wirings 34 for turning on and off each thin film transistor 10. A plurality of data wirings 36 for reading out charges through the thin film transistor 10 in the on state are provided.

The radiation detector 20 has a flat plate shape and a quadrilateral shape having four sides on the outer edge in a plan view, more specifically, a rectangular shape.

Next, the configuration of the electronic cassette 40 according to the present embodiment will be described. FIG. 6 is a perspective view showing the configuration of the electronic cassette 40 according to the present exemplary embodiment.

As shown in FIG. 6, the electronic cassette 40 according to the present embodiment includes a flat housing 41 made of a material that transmits radiation, and has a waterproof and airtight structure. A space (external space) A for accommodating various components is formed inside the housing 41, and the subject is transmitted through the space from the irradiation surface side of the housing 41 irradiated with the radiation X. The radiation detector 20 for detecting the radiation X and the lead plate 43 for absorbing the back scattered radiation of the radiation X are arranged in this order.

Here, in the electronic cassette 40 according to the present exemplary embodiment, the area corresponding to the arrangement position of the radiation detector 20 on one flat surface of the housing 41 is a quadrilateral imaging area 41A capable of detecting radiation. Has been. The surface having the imaging region 41A of the housing 41 is a top plate 41B in the electronic cassette 40. In the electronic cassette 40 according to the present embodiment, as shown in FIG. 8, the radiation detector 20 includes a TFT substrate. 30 is disposed on the top plate 41B side, and is attached to the inner surface of the casing 41 of the top plate 41B (the surface opposite to the surface on which radiation of the top plate 41B is incident).

By the way, the imaging system 104 according to the present embodiment has an imaging permission situation specifying function for specifying an imaging part and an imaging state that allow imaging by the electronic cassette 40 according to the temperature of the scintillator 8.

For this reason, in the electronic cassette 40 according to the present embodiment, as shown in FIG. 7, a temperature sensor 46 for detecting the temperature of the scintillator 8 is provided at the center of the lower surface side of the scintillator 8 of the radiation detector 20. Is provided. The temperature sensor 46 corresponds to a detection unit.

On the other hand, as shown in FIGS. 6 and 8, a cassette control unit 58 and a power supply unit, which will be described later, are located on one end inside the housing 41 at a position that does not overlap the radiation detector 20 (outside the range of the imaging region 41A). A case 42 for accommodating 70 (see FIG. 12 for both) is arranged.

The housing 41 is made of, for example, carbon fiber (carbon fiber), aluminum, magnesium, bionanofiber (cellulose microfibril), or a composite material in order to reduce the weight of the entire electronic cassette 40.

As the composite material, for example, a material including a reinforcing fiber resin is used, and the reinforcing fiber resin includes carbon, cellulose, and the like. Specifically, as the composite material, carbon fiber reinforced plastic (CFRP), a structure in which a foamed material is sandwiched with CFRP, or a material in which the surface of the foamed material is coated with CFRP is used. In the present embodiment, a structure in which a foam material is sandwiched with CFRP is used. Thereby, compared with the case where the housing | casing 41 is comprised with a carbon single-piece | unit, the intensity | strength (rigidity) of the housing | casing 41 can be improved.

On the other hand, as shown in FIG. 8, a support body 44 is disposed on the inner surface of the back surface portion 41 </ b> C facing the top plate 41 </ b> B inside the housing 41, and radiation detection is performed between the support body 44 and the top plate 41 </ b> B. The vessel 20 and the lead plate 43 are arranged in this order in the irradiation direction of the radiation X.

The support body 44 is made of, for example, a foam material from the viewpoint of weight reduction and absorption of dimensional deviation, and supports the lead plate 43.

As shown in FIG. 8 to FIG. 10, an adhesive member 80 is provided on the inner surface of the top plate 41B so that the TFT substrate 30 of the radiation detector 20 can be peeled off. As the adhesive member 80, for example, a double-sided tape is used. In this case, the double-sided tape is formed so that the adhesive force of one adhesive surface is stronger than the adhesive force of the other adhesive surface.

Specifically, the surface with weak adhesive strength (weak adhesive surface) is set to 1.0 N / cm or less with 180 ° peel adhesive strength. Then, the surface having a strong adhesive force (strong adhesion surface) is in contact with the top plate 41B, and the weak adhesion surface is in contact with the TFT substrate 30. Thereby, compared with the case where the radiation detector 20 is fixed to the top plate 41B with fixing members, such as a screw, the thickness of the electronic cassette 40 can be made thin. Even if the top plate 41B is deformed by an impact or load, the radiation detector 20 follows the deformation of the top plate 41B having high rigidity, so that only a large curvature (slow bend) is generated, and a local low curvature is generated. Therefore, the possibility that the radiation detector 20 is damaged is reduced. Furthermore, the radiation detector 20 contributes to the improvement of the rigidity of the top plate 41B. The double-sided tape also has an adhesive force on a surface other than the surface in contact with the TFT substrate 30 and the top plate 41B.

Further, as shown in FIG. 9, the adhesive member 80 is disposed along the side wall of the housing 41 in a band-like state. Thus, an internal space B is formed between the TFT substrate 30 and the top plate 41B in a state where the TFT substrate 30 is bonded to the top plate 41B (see also FIG. 8).

As shown in FIG. 10, the adhesive member 80 is formed with a communication passage 82 that communicates the internal space B and the external space A at portions corresponding to the corners of the top plate 41B. The communication path 82 is bent and specifically has four corners 84. That is, the communication path 82 has a labyrinth structure formed so as to be bent. In addition, the bending angle of the bent part (corner part 84) of the communication path 82 can be set arbitrarily, and may be bent like a bow. Further, the passage width d of the communication passage 82 is set as narrow as possible within a range where air can flow. However, the passage width d of the communication passage 82 may be set arbitrarily.

As described above, in the electronic cassette 40 according to the present exemplary embodiment, the radiation detector 20 is attached to the inside of the top plate 41B of the housing 41, so that the housing 41 is on the top plate 41B side and the back surface portion 41C side. When the radiation detector 20 is attached to the top plate 41B or the radiation detector 20 is peeled off from the top plate 41B, the housing 41 is placed on the top plate 41B side. And the back surface portion 41C side are separated into two.

In the present embodiment, the radiation detector 20 may not be bonded to the top plate 41B in a clean room or the like. This is because when a foreign object such as a metal piece that absorbs radiation is mixed between the radiation detector 20 and the top plate 41B, the foreign object can be removed by peeling the radiation detector 20 from the top plate 41B.

By the way, when the radiation detector 20 is peeled from the top plate 41B so as to directly grip the radiation detector 20, the side wall of the housing 41 becomes an obstacle. Therefore, as shown in FIG. 11, ears 86 may be provided on the TFT substrate 30 of the radiation detector 20. Thus, the operator can easily peel the radiation detector 20 from the top board 41B while holding the ear 86. The ear 86 may be fixed to the TFT substrate 30 or may be detachable from the TFT substrate 30. In the latter case, it is possible to eliminate the concern that the ear 86 becomes an obstacle when capturing a radiographic image.

Next, with reference to FIG. 12, the main configuration of the electrical system of the imaging system 104 according to the present embodiment will be described.

As shown in FIG. 12, in the radiation detector 20 built in the electronic cassette 40, a gate line driver 52 is arranged on one side of two adjacent sides, and a signal processing unit 54 is arranged on the other side. Each gate wiring 34 of the TFT substrate 30 is connected to a gate line driver 52, and each data wiring 36 of the TFT substrate 30 is connected to a signal processing unit 54.

Further, the housing 41 includes an image memory 56, a cassette control unit 58, and a wireless communication unit 60.

Each thin film transistor 10 of the TFT substrate 30 is sequentially turned on in a row unit by a signal supplied from the gate line driver 52 via the gate wiring 34, and the electric charge read by the thin film transistor 10 in the on state is converted into an electric signal. The data wiring 36 is transmitted and input to the signal processing unit 54. As a result, the charges are sequentially read out in units of rows, and a two-dimensional radiation image can be acquired.

Although not shown, the signal processing unit 54 includes an amplification circuit and a sample hold circuit for amplifying an input electric signal for each data wiring 36, and the electric signal transmitted through the individual data wiring 36. Is amplified by the amplifier circuit and then held in the sample hold circuit. Further, a multiplexer and an A / D (analog / digital) converter are connected in order to the output side of the sample and hold circuit, and the electric signals held in the individual sample and hold circuits are sequentially (serially) input to the multiplexer. The digital image data is converted by an A / D converter.

An image memory 56 is connected to the signal processing unit 54, and image data output from the A / D converter of the signal processing unit 54 is sequentially stored in the image memory 56. The image memory 56 has a storage capacity capable of storing a predetermined number of image data, and image data obtained by imaging is sequentially stored in the image memory 56 each time a radiographic image is captured.

The image memory 56 is connected to the cassette control unit 58. The cassette control unit 58 includes a microcomputer, and includes a CPU (Central Processing Unit) 58A, a memory 58B including a ROM (Read Only Memory) and a RAM (Random Access Memory), a nonvolatile storage unit 58C including a flash memory and the like. And controls the entire operation of the electronic cassette 40.

In addition, the temperature sensor 46 is connected to the cassette control unit 58, and the cassette control unit 58 is arranged at a location where the temperature sensor 46 is disposed (in the present embodiment, the center on the lower surface side of the scintillator 8 in the radiation detector 20). Temperature).

Furthermore, a wireless communication unit 60 is connected to the cassette control unit 58. The wireless communication unit 60 corresponds to a wireless LAN (Local Area Network) standard represented by IEEE (Institute of Electrical and Electronics Electronics) (802.11a / b / g), and communicates with external devices by wireless communication. Control transmission of various information. The cassette control unit 58 can wirelessly communicate with an external device such as the console 110 that performs control related to radiographic image capturing via the wireless communication unit 60, and can transmit and receive various types of information to and from the console 110 and the like. It is possible.

The electronic cassette 40 is provided with a power supply unit 70, which functions as the above-described various circuits and elements (gate line driver 52, signal processing unit 54, image memory 56, wireless communication unit 60, and cassette control unit 58). The microcomputer or the like) is operated by the power supplied from the power supply unit 70. The power supply unit 70 incorporates a battery (a rechargeable secondary battery) so as not to impair the portability of the electronic cassette 40, and supplies power from the charged battery to various circuits and elements. In FIG. 12, wiring for connecting the power supply unit 70 to various circuits and elements is omitted.

On the other hand, the console 110 is configured as a server computer, and includes a display 111 that displays an operation menu, a captured radiographic image, and the like, and a plurality of keys, and inputs various information and operation instructions. An operation panel 112.

The console 110 according to the present embodiment includes a CPU 113 that controls the operation of the entire apparatus, a ROM 114 that stores various programs including a control program in advance, a RAM 115 that temporarily stores various data, and various data. An HDD (Hard Disk Drive) 116 that stores and holds, a display driver 117 that controls display of various types of information on the display 111, and an operation input detection unit 118 that detects an operation state of the operation panel 112 are provided. . In addition, the console 110 transmits and receives various types of information such as an exposure condition, which will be described later, to and from the radiation generation apparatus 120 through wireless communication, and transmits and receives various types of information such as image data to and from the electronic cassette 40. A wireless communication unit 119 is provided. The CPU 113 corresponds to a specifying unit, a warning unit, and a presentation unit, and the HDD 116 corresponds to a storage unit.

The CPU 113, ROM 114, RAM 115, HDD 116, display driver 117, operation input detection unit 118, and wireless communication unit 119 are connected to each other via a system bus BUS. Therefore, the CPU 113 can access the ROM 114, RAM 115, and HDD 116, controls the display of various information on the display 111 via the display driver 117, and the radiation generator 120 via the wireless communication unit 119 and Control of transmission and reception of various types of information with the electronic cassette 40 can be performed. Further, the CPU 113 can grasp the operation state of the user with respect to the operation panel 112 via the operation input detection unit 118.

On the other hand, the radiation generator 120 includes a radio communication unit 123 that transmits and receives various types of information such as an exposure condition between the radiation source 121 and the console 110, and a line that controls the radiation source 121 based on the received exposure condition. A source control unit 122.

The radiation source control unit 122 is also configured to include a microcomputer, and stores the received exposure conditions and the like. The exposure conditions received from the console 110 include information such as tube voltage, tube current, and exposure period. The radiation source control unit 122 causes the radiation source 121 to emit radiation X based on the received exposure conditions.

By the way, as described above, the imaging system 104 according to the present embodiment has an imaging permission situation specifying function for specifying an imaging part and an imaging state that allow imaging by the electronic cassette 40 according to the temperature of the scintillator 8. Yes. For this reason, in the console 110 according to the present embodiment, the shooting information illustrated in FIG. 13 is stored in advance in the HDD 116 as an example.

As shown in FIG. 13, the imaging information according to the present embodiment is configured by previously storing an imaging region and an imaging state that allow imaging by the electronic cassette 40 within a predetermined temperature range of the scintillator 8. ing. As shown in FIG. 13, in the imaging system 104 according to the present embodiment, two types of “arm part” and “leg part” are applied as the imaging parts that allow the imaging, and the imaging is permitted. As the shooting state to be performed, two types of “standing position shooting” in which shooting is performed using the standing table 160 and “upright position shooting” in which shooting is performed using the standing table 164 are applied, but the present invention is not limited thereto. It goes without saying that it is not.

In the example shown in FIG. 13, for example, when the temperature of the scintillator 8 is 0 degree or more and less than 25 degrees, photographing parts and photographing states that are allowed to be photographed are “standing position photographing”, “arm part”, “leg part”. , And “posture shooting”, which indicates that shooting is allowed for all of these. In addition, for example, when the temperature of the scintillator 8 is equal to or higher than 35 degrees, the imaging part and the imaging state in which imaging is permitted are only “standing position imaging”.

That is, when performing the standing position photographing, the subject is hardly pressurized against the top plate 41B of the electronic cassette 40, and thus the standing position photographing is allowed in the entire temperature range. On the other hand, since the subject is covered with the top plate 41B of the electronic cassette 40 when performing the recumbent photographing, the pressure on the top plate 41B is relatively large, and the scintillator 8 Shooting is allowed only when the temperature is relatively low (in this embodiment, when the temperature is not less than 0 degrees and less than 25 degrees).

Next, the operation of the imaging system 104 according to the present embodiment will be described.

First, the operation of the console 110 when taking a radiographic image will be described with reference to FIG. FIG. 14 is a flowchart showing a flow of processing of the radiographic image capturing processing program executed by the CPU 113 of the console 110 at this time, and the program is stored in a predetermined area of the ROM 114 in advance.

In step 300 of FIG. 14, the display driver 117 is controlled so that a predetermined initial information input screen is displayed on the display 111, and the next step 302 waits for input of predetermined information.

FIG. 15 shows an example of an initial information input screen displayed on the display 111 by the process of step 300 described above. As shown in FIG. 15, in the initial information input screen according to the present embodiment, the name of the subject who is going to capture a radiographic image, the region to be imaged, and the posture at the time of capturing (in this embodiment, the supine position, the standing position) , And a message prompting the user to input radiation X exposure conditions at the time of imaging (in this embodiment, tube voltage, tube current, and exposure period when radiation X is exposed), and these The information input area is displayed.

When the initial information input screen shown in FIG. 15 is displayed on the display 111, the photographer can input the name of the subject to be imaged, the imaging region, the posture at the time of imaging, and the exposure conditions corresponding to each of the input areas. Is input via the operation panel 112.

When the posture at the time of imaging is the standing position or the lying position, the photographer holds the electronic cassette 40 in the holding section 162 of the corresponding standing table 160 or the holding section 166 of the lying table 164 and also the radiation source. After positioning 121 at the corresponding position, the subject is positioned at a predetermined imaging position. On the other hand, when a radiographic image is taken in a state where the imaging part does not hold the electronic cassette 40 such as an arm part or a leg part in the holding part, the photographer is ready to take a picture of the imaging part. The electronic cassette 40 and the radiation source 121 are positioned. Thereafter, the photographer designates an end button displayed near the lower end of the initial information input screen via the operation panel 112. When an end button is designated by the photographer, step 302 is affirmative and the process proceeds to step 304.

In step 304, instruction information for instructing transmission of information indicating the temperature measured by the temperature sensor 46 (hereinafter referred to as “temperature information”) is transmitted to the electronic cassette 40 via the wireless communication unit 119, and then In step 306, reception of the temperature information is awaited. When receiving the instruction information for instructing the transmission of the temperature information, the electronic cassette 40 transmits the temperature information to the console 110 via the wireless communication unit 60. In response to this, step 306 is affirmative and the process proceeds to step 308.

In step 308, the above-described shooting information (see also FIG. 13) is read from the HDD 116, and in the next step 310, the temperature indicated by the temperature information received from the electronic cassette 40 in the read shooting information is included. On the other hand, an imaging region and an imaging state in which radiographic imaging is allowed are specified.

In the next step 312, it is determined whether or not the imaging region and the imaging state specified by the processing in step 310 match information input on the initial information input screen (hereinafter referred to as “initial information”). If the determination is affirmative, the process proceeds to step 322, which will be described later, whereas if the determination is negative, the process proceeds to step 314.

In step 314, the display driver 117 is controlled to display a predetermined warning screen on the display 111, and in the next step 316, input of predetermined information is waited.

FIG. 16 shows an example of a warning screen displayed on the display 111 by the processing in step 314 described above. As shown in FIG. 16, in the warning screen according to the present embodiment, information indicating that the deterioration of the scintillator 8 is likely to proceed in the designated shooting, an alternative shooting situation (in the example shown in FIG. 16, “standing position shooting”). .) And information for prompting a selection input as to whether or not to change to the alternative shooting situation are displayed. In the present embodiment, as the alternative imaging situation, any one imaging situation of the imaging region and the imaging state specified by the processing in step 310 is applied.

When the warning screen shown in FIG. 16 is displayed on the display 111, when the photographer changes to the displayed alternative shooting situation, the subject, the electronic cassette 40, After changing the positional relationship of the radiation source 121, the “change” button displayed on the warning screen is designated via the operation panel 112. On the other hand, if the photographer does not change to the displayed alternative shooting situation, the photographer designates the “do not change” button displayed on the warning screen as it is via the operation panel 112. If any button is designated by the photographer, step 316 is affirmative and the process proceeds to step 318.

In step 318, it is determined whether or not the photographer has instructed to change the shooting state by determining whether or not the “change” button is designated on the warning screen. If the determination is negative, step 318 is performed. On the other hand, if the determination is affirmative, the process proceeds to step 320 so that the exposure condition included in the initial information becomes the exposure condition corresponding to the alternative photographing situation displayed on the warning screen. After changing to step 322, the process proceeds to step 322.

In step 322, the exposure condition is set by transmitting the exposure condition included in the initial information to the radiation generator 120 via the wireless communication unit 119. In response to this, the radiation source control unit 122 of the radiation generator 120 prepares for exposure under the received exposure conditions.

In the next step 324, instruction information for instructing the start of exposure is transmitted to the radiation generator 120 and the electronic cassette 40 via the wireless communication unit 119.

Correspondingly, the radiation source 121 generates and emits radiation X at a tube voltage, a tube current, and an exposure period according to the exposure conditions received by the radiation generator 120 from the console 110. The radiation X exposed from the radiation source 121 reaches the electronic cassette 40 after passing through the subject.

On the other hand, when the cassette control unit 58 of the electronic cassette 40 receives the instruction information instructing the start of exposure, the cassette control unit 58 starts accumulating charges in the capacitors 9 of the respective pixel units 32 of the built-in radiation detector 20. After the elapse of the exposure period specified by the exposure condition, the gate line driver 52 is controlled to output an ON signal to each gate wiring 34 one line at a time from the gate line driver 52, and each gate line 34 connected to each gate wiring 34. The thin film transistors 10 are sequentially turned on line by line.

In the radiation detector 20, when the thin film transistors 10 connected to the gate lines 34 are turned on one line at a time, the charges accumulated in the capacitors 9 one line at a time flow out to the data lines 36 as electric signals. The electric signal flowing out to each data wiring 36 is converted into digital image data by the signal processing unit 54 and stored in the image memory 56.

The cassette control unit 58 transmits the image data stored in the image memory 56 to the console 110 by wireless communication after the end of shooting.

Therefore, in the next step 326, the process waits until the image data is received from the electronic cassette 40, and in the next step 328, image processing for performing various corrections such as shading correction on the received image data is executed. To do.

In the next step 330, the image data subjected to the image processing (hereinafter referred to as “corrected image data”) is stored in the HDD 116, and in the next step 332, the radiation image indicated by the corrected image data is stored. The display driver 117 is controlled so as to be displayed on the display 111 for confirmation, etc., and in the next step 334, the corrected image data is transmitted to the RIS server 150 via the intra-hospital network 102, and then the radiographic imaging is performed. Terminate the processing program. Note that the corrected image data transmitted to the RIS server 150 is stored in the database 150A, so that the doctor can perform interpretation, diagnosis, and the like of the radiographic image taken.

Next, with reference to FIG. 17, the operation of the electronic cassette 40 when receiving the instruction information for instructing the transmission of the temperature information transmitted by the process of step 304 of the radiographic image capturing processing program will be described. FIG. 17 is a flowchart showing the flow of the temperature information transmission processing program executed by the CPU 58A of the electronic cassette 40 at this time, and the program is stored in advance in a predetermined area of the memory 58B.

In step 400 of FIG. 17, temperature information indicating the temperature of the scintillator 8 at this time is derived based on a signal input from the temperature sensor 46, and in the next step 402, the derived temperature information is converted to wireless communication. It transmits to the console 110 via the part 60, and complete | finishes this temperature information transmission process program after that.

Incidentally, in the electronic cassette 40 according to the present embodiment, as shown in FIG. 8, the radiation detector 20 is incorporated so that the radiation X is irradiated from the TFT substrate 30 side.

Here, as shown in FIG. 20, the radiation detector 20 is irradiated with radiation from the side where the scintillator 8 is formed, and reads the radiation image by the TFT substrate 30 provided on the back side of the incident surface of the radiation. In the case of a so-called back surface reading method, light is emitted more intensely on the upper surface side (opposite side of the TFT substrate 30) of the scintillator 8, and radiation is irradiated from the TFT substrate 30 side. In the case of a so-called surface reading method in which a radiation image is read by the TFT substrate 30 thus formed, the radiation transmitted through the TFT substrate 30 enters the scintillator 8 and the TFT substrate 30 side of the scintillator 8 emits light more strongly. Electric charges are generated in each sensor unit 13 provided on the TFT substrate 30 by light generated by the scintillator 8. For this reason, since the radiation detector 20 is closer to the light emission position of the scintillator 8 with respect to the TFT substrate 30 when the front surface reading method is used than when the rear surface reading method is used, the resolution of the radiation image obtained by imaging is higher. high.

In the radiation detector 20, the photoelectric conversion film 4 is made of an organic photoelectric conversion material, and the photoelectric conversion film 4 hardly absorbs radiation. For this reason, the radiation detector 20 according to the present embodiment suppresses a decrease in sensitivity to radiation because the amount of radiation absorbed by the photoelectric conversion film 4 is small even when radiation is transmitted through the TFT substrate 30 by the surface reading method. Can do. In the surface reading method, radiation passes through the TFT substrate 30 and reaches the scintillator 8. As described above, when the photoelectric conversion film 4 of the TFT substrate 30 is made of an organic photoelectric conversion material, the photoelectric conversion film 4 hardly absorbs radiation and can suppress radiation attenuation to a small extent. ing.

Further, both the amorphous oxide constituting the active layer 17 of the thin film transistor 10 and the organic photoelectric conversion material constituting the photoelectric conversion film 4 can be formed at a low temperature. For this reason, the board | substrate 1 can be formed with a plastic resin, aramid, and bio-nanofiber with little radiation absorption. Since the substrate 1 formed in this way has a small amount of radiation absorption, even when the radiation passes through the TFT substrate 30 by the surface reading method, it is possible to suppress a decrease in sensitivity to radiation.

Further, according to the present embodiment, as shown in FIG. 8, the radiation detector 20 is attached to the top plate 41B in the housing 41 so that the TFT substrate 30 is on the top plate 41B side. When the substrate 1 is formed of a highly rigid plastic resin, aramid, or bionanofiber, the radiation detector 20 itself has high rigidity, so that the top plate 41B of the housing 41 can be formed thin. In addition, when the substrate 1 is formed of a highly rigid plastic resin, aramid, or bionanofiber, the radiation detector 20 itself has flexibility, so that even when an impact is applied to the imaging region 41A, the radiation detector 20 is damaged. It ’s hard.

As described above in detail, in the present embodiment, based on the temperature of the scintillator 8, at least one of an imaging region and an imaging state that allow predetermined imaging according to the temperature of the scintillator 8 is specified. Therefore, by taking radiographic images by applying at least one of the specified imaging region and imaging state, it is possible to reduce radiographic imaging restrictions according to the scintillator temperature while suppressing degradation of the scintillator. Can do.

In particular, when the scintillator 8 includes CsI, CsI has a large coefficient of thermal expansion of about 50 PPM, and when the temperature of CsI rises, the gap (about 1 to several μm) between CsI columnar crystals becomes narrower. There is a high possibility that the columnar crystals come into contact with each other due to the deformation of the radiation detector 20 due to the load.

Therefore, when the one containing CsI is applied as the scintillator 8, it is extremely effective to limit the photographing applied with a large load as the temperature of the scintillator 8 is increased as in the present embodiment.

In the present embodiment, since the warning is given when the identification result of at least one of the imaging region and the imaging state does not match the actual imaging situation, the convenience for the user can be further improved.

In this embodiment, when the specified shooting state does not match the actual shooting state and there is an alternative shooting state, the alternative shooting state is presented, which is convenient for the user. The sex can be further improved.

Further, in the present embodiment, since the shooting state includes shooting in the supine position and shooting in the standing position, in the mode in which these shootings are performed, the temperature of the scintillator is controlled while suppressing deterioration of the scintillator. The restriction of radiographic image capturing can be relaxed.

Moreover, in this Embodiment, since the sensor part 13 is comprised including the organic photoelectric conversion material which generate | occur | produces an electric charge by receiving the light which generate | occur | produced in the scintillator 8, the impact resistance of the electronic cassette 40 is improved. Can be made.

Further, in the present embodiment, the radiation detector 20 is directly attached to the surface opposite to the surface on which the radiation is incident on the top plate 41B having a transmission surface through which the radiation transmitted through the subject is transmitted. The impact resistance of the electronic cassette 40 can be improved.

In particular, in the present embodiment, since the radiation detector 20 is attached to the top plate 41B so as to be separable, the casing can be exchanged efficiently.

In the present embodiment, since the top plate 41B constitutes a part of the housing 41 that houses the radiation detector 20, it is simpler than when the top plate is configured separately from the housing. A top plate can be constructed.

In the present embodiment, since the internal space B is formed between the TFT substrate 30 and the top plate 41B, when the radiation detector 20 is bonded to the top plate 41B, the TFT substrate 30 and the top plate 41B are bonded. Even if air remains on the bonding surface of the member 80, the remaining air can escape to the internal space B. In addition, since the communication member 82 that communicates the internal space B and the external space A is formed in the adhesive member 80, the pressure in the internal space B and the air pressure in the external space A can be reduced even when the atmospheric pressure in the external space A changes. Can be kept constant. Thereby, it can prevent that the adhesiveness of the TFT substrate 30 with respect to the top plate 41B falls by atmospheric pressure change.

Further, in the present embodiment, the communication passage 82 has a corner portion 84. Therefore, even when foreign matter having a mass larger than that of air flows into the communication path 82 from the external space A, the foreign matter cannot follow the flow of air flowing through the corner portion 84. Mixing into B can be prevented. As a result, it is possible to suppress contamination of foreign matter that leads to deterioration of the quality of the radiation image.

Further, since the communication path 82 is formed in the adhesive member 80 and the adhesive member 80 has adhesive force on the entire surface, the foreign matter that could not follow the air adheres to the wall surface of the communication path 82 at the corner 84. It becomes easy. Therefore, the foreign matter can be reliably captured in the communication path 82. Therefore, it is possible to more reliably prevent foreign matter from entering the internal space B.

Further, according to the present embodiment, the passage width d of the communication passage 82 is set as narrow as possible within the range in which air can circulate, so that it is possible to cope with the mixing of foreign matters such as relatively small metal powder. it can. If the passage width d of the communication passage 82 is set according to the assumed size of the foreign matter, it is possible to efficiently prevent the foreign matter from being mixed.

Incidentally, the scintillator 8 is generally more fragile than the TFT substrate 30. Therefore, when the scintillator 8 is bonded to the top plate 41B with the adhesive member 80, the scintillator 8 may be damaged when the radiation detector 20 is peeled off. However, in the present embodiment, since the TFT substrate 30 is bonded to the top plate 41B with the adhesive member 80, the concern that the scintillator 8 is damaged when the radiation detector 20 is peeled can be eliminated.

Depending on the shooting environment, shooting may be performed with the subject (patient) on the top board 41B. In this case, the top plate 41B is easily damaged. When the top plate 41B is scratched, it may be displayed on the radiographic image as fixed pattern noise, so it is desirable to replace the housing 41. However, when the radiation detector 20 is pasted to the top plate 41B so as not to be peeled off, it is necessary to replace the expensive radiation detector 20 together when the casing 41 is replaced, which increases costs. According to the present embodiment, since the radiation detector 20 is detachably bonded to the top plate 41B, the housing 41 can be efficiently replaced.

[Second Embodiment]
In the second embodiment, an example in which the temperature of the scintillator 8 is detected based on a dark current generated in the sensor unit 13 of the radiation detector 20 will be described. That is, in the present embodiment, since the radiation detector 20 is configured such that the scintillator 8 and the TFT substrate 30 are in close contact with each other, the temperature of the scintillator 8 is detected using the dark current generated on the TFT substrate 30 side. Is. Note that the configuration of the imaging system 104 according to the present embodiment is the same as that of the imaging system 104 according to the first embodiment, and a description thereof will be omitted here.

First, with reference to FIG. 18, the operation of the console 110 according to the second embodiment when radiographic images are taken will be described. FIG. 18 is a flowchart showing the flow of processing of the radiographic imaging program according to the second embodiment, which is executed by the CPU 113 of the console 110 at this time, and the program is stored in a predetermined area of the ROM 114. Stored in advance. Also, steps in FIG. 18 that execute the same processing as in FIG. 14 are assigned the same step numbers as in FIG. 14, and descriptions thereof are omitted.

In step 304 ′ of FIG. 18, instruction information for instructing transmission of information indicating the dark current generated in the sensor unit 13 of the radiation detector 20 (hereinafter referred to as “dark current information”) is transmitted to the electronic cassette 40 as a wireless communication unit. After the transmission via 119, the next step 306 ′ waits for reception of the dark current information. When receiving the instruction information instructing transmission of the dark current information, the electronic cassette 40 transmits the dark current information to the console 110 via the wireless communication unit 60. In response, step 306 ′ is affirmative and the process proceeds to step 307.

In step 307, temperature information indicating the temperature of the scintillator 8 is derived based on the dark current information received from the electronic cassette 40. In the present embodiment, information indicating the relationship between the dark current of the electronic cassette 40 and the temperature of the scintillator 8 is obtained from an experiment using an actual machine of the same type as the electronic cassette 40 or a computer / computer based on the design specifications of the electronic cassette 40. The temperature information is derived by deriving a temperature corresponding to the dark current indicated by the dark current information received from the information in advance by simulation or the like.

In addition, it is known that the dark current is approximately doubled at 8 ° C. without being limited to this form. Therefore, when the electronic cassette 40 is shipped from the factory, the dark current value at the predetermined temperature and the predetermined temperature May be stored in advance, and the temperature may be calculated backward from the difference between the dark current value indicated by the dark current information received from the electronic cassette 40 and the dark current value stored in advance.

Thereafter, in step 310 ′, radiographic images are allowed to be captured in the temperature range to which the temperature indicated by the temperature information derived by the processing of step 307 belongs in the imaging information read out by the processing of step 308. And the shooting state.

Next, with reference to FIG. 19, the operation of the electronic cassette 40 when receiving the instruction information for instructing the transmission of the dark current information transmitted by the process of step 304 'of the radiographic imaging processing program will be described. FIG. 19 is a flowchart showing the flow of the dark current information transmission processing program executed by the CPU 58A of the electronic cassette 40 at this time, and the program is stored in advance in a predetermined area of the memory 58B.

In step 450 of FIG. 19, dark current information indicating the dark current of the sensor unit 13 in the radiation detector 20 at this time is derived as follows.

That is, first, after performing a reset operation for discharging the charges accumulated in the radiation detector 20 at this time, imaging is performed by the radiation detector 20 in a predetermined charge accumulation period. At this time, since radiation is not exposed, the image data obtained by the imaging is information indicating the dark current in the sensor unit 13 of the radiation detector 20.

Then, from the image data obtained as described above, an average value of data corresponding to a predetermined region (in this embodiment, a partial region including the central portion of the radiation detector 20) is derived as dark current information. .

In the next step 452, the dark current information derived by the processing in step 450 is transmitted to the console 110 via the wireless communication unit 60, and then the dark current information transmission processing program is terminated.

As described above in detail, in the present embodiment, in addition to the effects of the first embodiment, the temperature of the scintillator 8 is detected based on the dark current generated in the sensor unit 13. Compared with the case where the temperature of 8 is detected by the temperature sensor, the cost can be further reduced.

As mentioned above, although this invention was demonstrated using embodiment, the technical scope of this invention is not limited to the range as described in the said embodiment. Various modifications or improvements can be added to the above-described embodiment without departing from the gist of the invention, and embodiments to which such modifications or improvements are added are also included in the technical scope of the present invention.

Further, the above-described embodiment does not limit the invention according to the claims, and all combinations of features described in the embodiment are not necessarily essential to the solution means of the invention. The embodiments described above include inventions at various stages, and various inventions can be extracted by appropriately combining a plurality of disclosed constituent elements. Even if some constituent requirements are deleted from all the constituent requirements shown in the embodiment, as long as an effect is obtained, a configuration from which these some constituent requirements are deleted can be extracted as an invention.

For example, in the above-described embodiment, a case has been described in which the console 110 presents a warning or an alternative shooting situation when the shooting situation that allows shooting does not match the actual shooting situation. However, the present invention is not limited to this. However, these may be executed in the electronic cassette 40. In this case, the load on the console 110 can be reduced as compared with the above embodiment.

In the above embodiment, the case where the sensor unit 13 is configured to include an organic photoelectric conversion material that generates charges by receiving light generated by the scintillator 8 has been described. It is not limited, It is good also as a form which applies what was comprised without including an organic photoelectric conversion material as the sensor part 13. FIG.

In the above embodiment, the case where only one alternative shooting situation is presented has been described. However, the present invention is not limited to this, and when there are a plurality of alternative shooting situations, A combination of two or more shooting situations may be presented. In this case, as compared with the above-described embodiment, since there are more choices of imaging conditions by the photographer, it is possible to further relax restrictions on radiographic imaging according to the scintillator temperature.

Moreover, although the said embodiment demonstrated the case where the corner | angular part 84 was provided with two or more in the communicating path 82, this invention is not limited to this, As shown in FIG. Only one corner 92 may be provided. Thereby, the communication path 90 can be easily formed in the adhesive member 80.

Further, when the radiation detector 20 is peeled from the top plate 41B, an organic solvent or the like may be poured into the adhesive member 80 to weaken the adhesiveness of the adhesive member 80 and then the radiation detector 20 may be peeled off. In this case, since the adhesive member 80 has corners, the organic solvent can easily penetrate into the adhesive member 80.

Furthermore, in the above-described embodiment, the case has been described in which the case 42 that accommodates the cassette control unit 58 and the power supply unit 70 and the radiation detector 20 are arranged in the housing 41 of the electronic cassette 40 so as not to overlap. It is not limited to this. For example, the radiation detector 20 and the cassette control unit 58 or the power supply unit 70 may be arranged so as to overlap each other.

Moreover, although the said embodiment demonstrated the case where it communicated by radio | wireless between the electronic cassette 40 and the console 110, and between the radiation generator 120 and the console 110, this invention is limited to this. For example, at least one of these may be configured to perform wired communication.

In the above embodiment, the case where X-rays are applied as radiation has been described. However, the present invention is not limited to this, and other radiation such as γ-rays may be applied.

Further, as the sensor unit 13 of the radiation detector 20, an organic CMOS sensor in which the photoelectric conversion film 4 is made of a material containing an organic photoelectric conversion material may be used. As the TFT substrate 30 of the radiation detector 20, the thin film transistor 10. An organic TFT array sheet in which organic transistors including the organic material are arranged in an array on a flexible sheet may be used. The above organic CMOS sensor is disclosed in, for example, Japanese Patent Application Laid-Open No. 2009-212377. In addition, the organic TFT array sheet described above is, for example, “Nihon Keizai Shimbun,“ The University of Tokyo, “Developing“ Ultra Flexible ”Organic Transistor” ”, [online], [Search May 8, 2011], Internet <URL : Http://www.nikkei.com/tech/trend/article/g=96958A9C93819499E2EAE2E0E48DE2EAE3E3E0E2E3E2E2E2E2E2E2E2; p = 9694E0E7E2E6E0E2E3E2E2E0E2E0> ”

When a CMOS sensor is used as the sensor unit 13 of the radiation detector 20, the advantage of being able to perform photoelectric conversion at high speed and the result of being able to thin the substrate are the surface reading method (hereinafter referred to as ISS (Irradiation Side Sampling) method). .) Can be used to suppress the absorption of radiation and can be suitably applied to mammography.

On the other hand, as a defect when a CMOS sensor is used as the sensor unit 13 of the radiation detector 20, there is a low resistance to radiation when a crystalline silicon substrate is used. For this reason, conventionally, there has been a technique for taking measures such as providing an FOP (fiber optical plate) between the sensor unit and the TFT substrate.

Based on this drawback, a technique using a SiC (silicon carbide) substrate as a semiconductor substrate having high resistance to radiation can be applied. Advantages that can be used as an ISS method by using a SiC substrate, and because SiC has a lower internal resistance and a smaller amount of heat generation than Si, it suppresses the amount of heat generation when shooting movies, and raises the temperature of CsI There is an advantage that it is possible to suppress a decrease in sensitivity due to.

As described above, a substrate having a high resistance to radiation such as a SiC substrate is generally a wide cap (about 3 eV), and as an example, as shown in FIG. 24, the absorption edge is about 440 nm corresponding to the blue region. Therefore, in this case, a scintillator such as CsI: Tl or GOS that emits light in the green region cannot be used.

In contrast, the scintillator that emits light in these green regions has been actively researched due to the sensitivity characteristics of amorphous silicon, and therefore there is a high demand for using the scintillator. For this reason, the scintillator which light-emits in a green area | region can be used by comprising the photoelectric converting film 4 with the material containing the organic photoelectric conversion material which absorbs light emission in a green area | region.

When the photoelectric conversion film 4 is formed of a material containing an organic photoelectric conversion material and the thin film transistor 10 is formed using a SiC substrate, the photoelectric conversion film 4 and the thin film transistor 10 have different sensitivity wavelength regions, and thus the light emitted by the scintillator is emitted. There is no noise of the thin film transistor 10.

Further, if SiC and a material containing an organic photoelectric conversion material are laminated as the photoelectric conversion film 4, in addition to receiving light emission mainly in the blue region, such as CsI: Na, light emission in the green region is also received. As a result, the sensitivity can be improved. In addition, since the organic photoelectric conversion material hardly absorbs radiation, it can be suitably used for the ISS system.

Note that SiC is highly resistant to radiation because it is difficult for nuclear nuclei to be blown off even when exposed to radiation. Develop semiconductor devices that can be used for a long time ", [online], [Search May 8, 2011], Internet <URL: http://www.jaea.go.jp/jari/jpn/publish/01/ff/ ff36 / sic.html> ”.

Moreover, C (diamond), BN, GaN, AlN, ZnO etc. are mentioned as a semiconductor material with high tolerance with respect to radiations other than SiC. These light element semiconductor materials have high radiation resistance because they are mainly wide-gap semiconductors, so they require high energy for ionization (electron-hole pair formation), small reaction cross-sections, This is due to the fact that bonding is strong and atomic displacement is less likely to occur. Regarding this point, for example, “Electronics Research Institute,“ New Development of Nuclear Electronics ”, [online], [Search May 8, 2011], Internet <URL: http: //www.aist .go.jp / ETL / jp / results / bulletin / pdf / 62-10to11 / kobayashi150.pdf> ”. Regarding the radiation resistance of GaN, for example, “Tohoku University,“ Evaluation of radiation resistance of gallium nitride device ”, [online], [Search May 8, 2011], Internet <URL: http: // cycgw1 .cyric.tohoku.ac.jp / ~ sakemi / ws2007 / ws / pdf / narita.pdf> ”.

In addition, since GaN has good thermal conductivity as a use other than blue LEDs and has high insulation resistance, ICs are being studied in the field of power systems. As for ZnO, an LED that emits light mainly in the blue to ultraviolet region has been studied.

By the way, when SiC is used, the band gap Eg is changed from about 1.1 eV to about 2.8 eV of Si, so that the light absorption wavelength λ shifts to the short wavelength side. Specifically, since the wavelength λ = 1.24 / Eg × 1000, the sensitivity changes to wavelengths up to about 440 nm. Therefore, when SiC is used, as shown in FIG. 25 as an example, the scintillator emits light in the blue region more than CsI: Tl (peak wavelength: about 565 nm) that emits light in the green region, as well as CsI: Na (peak wavelength: about 420 nm). This is more suitable as the emission wavelength. Since the phosphor emits blue light well, CsI: Na (peak wavelength: about 420 nm), BaFX: Eu (X is a halogen such as Br and I, peak wavelength: about 380 nm), CaWO ₄ (peak wavelength: about 425 nm) ZnS: Ag (peak wavelength: about 450 nm), LaOBr: Tb, Y ₂ O ₂ S: Tb, and the like are suitable. In particular, BaFX: Eu used in CsI: Na and CR cassettes, and CaWO ₄ used in screens and films are preferably used.

On the other hand, as a CMOS sensor having high resistance to radiation, a CMOS sensor may be configured by using a configuration of Si substrate / thick film SiO ₂ / organic photoelectric conversion material by SOI (Silicon On Insulator).

Technologies that can be applied to this configuration include, for example, “Japan Aerospace Exploration Agency (JAXA) Institute for Space Science,“ High radiation resistance by combining the most advanced consumer SOI technology and radiation resistance technology for space. “Development of functional logic integrated circuit development platform for the first time in the world”, [online], [Search May 8, 2011], Internet <URL: http://www.jaxa.jp/press/2010/11/20101122_soi_j .html> ".

In addition, since the radiation resistance of the film thickness SOI is high in the SOI, examples of the high radiation durability element include a complete separation type thick film SOI and a partial separation type thick film SOI. As for these SOIs, for example, “Patent Office,“ Patent Application Technology Trend Survey Report on SOI (Silicon On Insulator) Technology ”, [online], [Search May 8, 2011], Internet <URL: http://www.jpo.go.jp/shiryou/pdf/gidou-houkoku/soi.pdf> ”.

Further, even if the thin film transistor 10 or the like of the radiation detector 20 does not have light transmission (for example, a structure in which the active layer 17 is formed of a material having no light transmission such as amorphous silicon), the thin film transistor 10 or the like. Is disposed on a light-transmitting substrate 1 (for example, a flexible substrate made of synthetic resin), and a portion of the substrate 1 where the thin film transistor 10 or the like is not formed is configured to transmit light. It is possible to obtain a radiation detector 20 having optical transparency. Arranging the thin film transistor 10 or the like having a non-light-transmitting structure on the light-transmitting substrate 1 is performed by separating the micro device block manufactured on the first substrate from the first substrate. This can be realized by applying the technology disposed above, specifically, for example, FSA (Fluidic Self-Assembly). The above FSA is, for example, “Toyama University,“ Study on Self-Aligned Placement Technology of Small Semiconductor Blocks ”, [online], [Search May 8, 2011], Internet <URL: http: //www3.u- toyama.ac.jp/maezawa/Research/FSA.html> ”.

In addition, the configuration of the RIS 100 described in the above embodiment (see FIG. 1), the configuration of the radiation imaging room (see FIG. 2), the configuration of the electronic cassette 40 (see FIGS. 3 to 11), and the imaging system 104 The configuration (see FIG. 12) is an example, and an unnecessary part can be deleted, a new part can be added, or the connection state can be changed without departing from the gist of the present invention. Needless to say.

The configuration of the shooting information described in the above embodiment (see FIG. 13) is also an example, and unnecessary information is deleted or new information is added without departing from the gist of the present invention. It goes without saying that you can do it.

Further, the processing flow of various programs described in the above embodiment (see FIGS. 14 and 17 to 19) is also an example, and unnecessary steps can be deleted without departing from the gist of the present invention. Needless to say, new steps can be added or the processing order can be changed.

Furthermore, the configuration of various screens described in the above embodiment (see FIGS. 15 and 16) is also an example, and unnecessary information is deleted or new information is added without departing from the gist of the present invention. Needless to say, it can be added.

The disclosures of Japanese Application 2010-192923 and Japanese Application 2011-137586 are incorporated herein by reference in their entirety. All documents, patent applications, and technical standards mentioned in this specification are to the same extent as if each individual document, patent application, and technical standard were specifically and individually described to be incorporated by reference, Incorporated herein by reference.

Claims

A radiation image capturing apparatus that includes a scintillator that converts incident radiation into light, and a radiation detector that includes a sensor unit that detects light converted by the scintillator, and that captures a radiation image indicated by the radiation;
A detector for detecting the temperature of the scintillator;
A radiographic image is captured by the storage unit in which imaging information indicating at least one of an imaging region and an imaging state in which imaging by the radiographic imaging device is allowed according to the temperature of the scintillator is stored, and the radiographic imaging device A specifying unit that specifies at least one of an imaging region and an imaging state that allow imaging by the radiographic imaging device from the imaging information stored in the storage unit based on the temperature detected by the detection unit. A control device for controlling the operation of the radiographic imaging device;
A radiographic imaging system comprising:
The radiographic imaging system according to claim 1, wherein the detection unit detects a temperature of the scintillator based on a dark current generated in the sensor unit.
The radiographic imaging system according to claim 1, wherein the control device further includes a warning unit that issues a warning when a result of identification by the identification unit does not match an actual imaging situation.
The specifying unit specifies at least the shooting state,
The control device further includes a presentation unit that presents the alternative shooting state when the shooting state specified by the specifying unit does not match the actual shooting state and there is an alternative shooting state. The radiographic imaging system according to any one of claims 1 to 3.
The radiographic imaging system according to any one of claims 1 to 4, wherein the imaging state includes imaging in a supine position and imaging in a standing position.
The radiographic imaging system according to any one of claims 1 to 5, wherein the sensor unit includes an organic photoelectric conversion material that generates charges by receiving light generated by the scintillator.
The said radiation detector is directly attached to the surface on the opposite side of the surface into which the said radiation enters of the top plate which has the permeation | transmission surface which the radiation which permeate | transmitted the object permeate | transmits. The radiation image capturing system according to claim 1.
The scintillator is configured to include cesium iodide,
The radiation image capturing system according to claim 7, wherein the radiation detector is stacked so that the radiation is incident on the sensor unit and the scintillator in this order.
The radiographic imaging system according to claim 7, wherein the radiation detector is detachably attached to the top plate.
The radiographic image capturing apparatus includes:
An adhesive member that bonds the radiation detector to the top plate so that an internal space is formed between the radiation detector and the top plate;
A ventilation portion that communicates the internal space and the outside, and prevents foreign matter from entering the internal space from the outside, and
The radiographic imaging system according to claim 7, further comprising:
The radiographic imaging system according to any one of claims 7 to 10, wherein the top plate constitutes a part of a housing that houses the radiation detector.
The radiographic imaging system according to any one of claims 1 to 7, wherein the scintillator includes cesium iodide.
A scintillator for converting incident radiation into light, and a radiation detector having a sensor unit for detecting the light converted by the scintillator;
A detector for detecting the temperature of the scintillator;
A storage unit in which imaging information indicating at least one of an imaging region and an imaging state allowing imaging by the radiation detector according to the temperature of the scintillator is stored;
An imaging region and an imaging state that allow imaging by the radiation detector from the imaging information stored in the storage unit based on the temperature detected by the detection unit when radiographic images are captured by the radiation detector A specific part that identifies at least one of
A radiographic imaging apparatus comprising:
Computer
A scintillator that converts incident radiation into light, and a radiation detector that includes a sensor unit that detects light converted by the scintillator, and includes a scintillator in a radiation image capturing apparatus that captures a radiation image indicated by the radiation. A detection unit for detecting a temperature based on a dark current generated in the sensor unit;
A specifying unit that specifies at least one of an imaging region and an imaging state that allow imaging by the radiographic imaging device based on a temperature detected by the detection unit when radiographic imaging is performed by the radiographic imaging device; ,
A computer-readable medium storing a program for functioning as a computer.