JP5634883B2 - Electronic cassette for radiography - Google Patents

Description

  The present invention relates to an electronic cassette for radiography having a portable housing.

  In the medical field, an X-ray imaging system for imaging a subject using radiation, for example, X-rays, is known in order to perform image diagnosis. The X-ray imaging system includes an X-ray image detection device that receives an X-ray irradiated by an X-ray source and transmitted through the subject and detects a radiographic image of the subject. The X-ray image detection apparatus has a detection surface in which pixels that accumulate signal charges according to the amount of incident X-rays are arranged in a matrix, and accumulates signal charges for each pixel on the detection surface, thereby An apparatus using an X-ray image detector (FPD: flat panel detector) that detects an X-ray image representing image information and outputs it as digital image data has been put into practical use.

  In addition, the X-ray image detection apparatus has a flat shape in addition to a stationary type in which an FPD is built in a standing position photographing stand or a standing position photographing stand for photographing a subject in a standing posture or a standing posture. A portable X-ray image detection apparatus (hereinafter referred to as “electronic cassette”) in which an FPD is built in a portable casing has also been developed. The electronic cassette, like other film cassettes using film or IP (imaging plate) and IP cassettes, is used in patient rooms for imaging patients who are difficult to move to the imaging room. It is used for photographing a part that is difficult to photograph when it is brought in or stationary (for example, extremities such as elbows and knee joints).

  The housing of the X-ray imaging cassette is firstly portable and lightweight, and secondly, the front portion of the housing transmits X-rays and makes X-rays enter the housing. X-ray transmission is high because it is an entrance surface. Third, when the electronic cassette is removed from the imaging table and used on a bed or table, the imaging site of the subject is located on the entrance surface of the housing. Since it is placed and a load is applied, the entrance surface is required to have basic performance such as rigidity enough to withstand the load applied from the imaging region.

  Patent Documents 1 and 2 disclose a transmission plate that uses a carbon material that is lightweight, has high rigidity, and has good X-ray transmission as a transmission plate used in a casing of a cassette. Patent Document 1 discloses a sandwich-structured transmission plate using CFRP (carbon fiber reinforced resin) and a resin reinforced with aromatic polyamide fibers (AFRP) and laminated so that one is an intermediate layer and the other is sandwiched from both sides. As described above, cracking of the surface of the transmission plate is prevented by covering CFRP with AFRP while securing rigidity. Patent Document 2 describes a transmission plate having a sandwich structure in which a CFRP core is sandwiched between both sides with a resin core material as an intermediate layer. By sandwiching a resin core material between CFRP, rigidity is improved. X-ray transparency is further improved while ensuring.

JP 2005-313613 A Japanese Utility Model Publication 2-48841

  By the way, since the detection panel which comprises FPD has the characteristic more sensitive to a temperature change than film or IP, there is little heat transmitted from the exterior to the housing | casing in which a detection panel is accommodated through a permeation | transmission board. Better. Patent Document 1 and Patent Document 2 do not disclose such problems and solutions.

  The present invention has been made in view of the above circumstances, and an object of the present invention is to provide an electronic cassette in which heat is not easily transmitted from the outside of the casing to the inside of the casing through the transmission plate.

The present invention receives the radiation transmitted through the object, a radiation image detector for detecting a radiation image of an object, a housing to house the radiological image detector, in the housing, transmitted through the radiological Radiation is transparent plate constituting the incident surface for incident on the image detector, the first layer of the outermost layer constituting the outer surface of the housing, the thermal conductivity of more than 150 W / mK PITCH-based carbon fibers The transmission plate is made of a PAN-based carbon material in which the second layer located on the inner side of the first layer is formed of PAN-based carbon fiber. It is what has been .

Toru Kaita, rather than the second layer and the third layer located on the inner side is constituted by a P ITCH based carbon material, the second layer is a sandwich structure sandwiched on both sides or al P ITCH based carbon material It is preferable.

  According to the present invention, the first layer, which is the outermost layer constituting the outer surface of the housing, is made of a PITCH-based carbon material formed of PITCH-based carbon fibers having at least a thermal conductivity of 150 W / mK or more. Therefore, it is possible to provide a radiographic electronic cassette in which heat is not easily transmitted from the outside of the housing to the inside of the housing through the transmission plate.

It is explanatory drawing of the X-ray imaging system which uses an electronic cassette. It is an external appearance perspective view of an electronic cassette. It is explanatory drawing of FPD. It is a disassembled perspective view of an electronic cassette. It is sectional drawing of an electronic cassette. It is a block diagram of a permeation | transmission board. It is sectional drawing of a permeation | transmission board. It is a figure which shows the measurement result of thermography.

  In FIG. 1, the X-ray imaging system 10 includes an X-ray generation device 11 and an X-ray imaging device 12. The X-ray generator 11 includes an X-ray source 13, a radiation source controller 14 that controls the X-ray source 13, and an irradiation switch 15. The X-ray source 13 includes an X-ray tube 13a that emits X-rays and an irradiation field limiter (collimator) 13b that limits the irradiation field of the X-rays emitted by the X-ray tube.

  The X-ray tube 13a has a cathode made of a filament that emits thermoelectrons, and an anode (target) that emits X-rays when the thermoelectrons emitted from the cathode collide. The irradiation field limiter 13b has, for example, a plurality of lead plates that shield X-rays arranged in a cross pattern, and an irradiation opening that transmits X-rays is formed in the center, and moves the position of the lead plate. By changing the size of the irradiation aperture, the irradiation field is limited.

  The radiation source control device 14 determines a high voltage generator that supplies a high voltage to the X-ray source 13, a tube voltage that determines the energy spectrum of the X-rays that the X-ray source 13 irradiates, and an irradiation amount per unit time. It consists of a controller that controls the tube current and the irradiation time during which X-ray irradiation continues. The high voltage generator boosts the input voltage with a transformer to generate a high voltage tube voltage, and supplies driving power to the X-ray source 13 through a high voltage cable. The imaging conditions such as the tube voltage, the tube current, and the irradiation time are set manually by an engineer from the operation panel of the radiation source control device 14 and are set from the X-ray imaging device 12 via a communication cable.

  The irradiation switch 15 is an input unit that inputs an operation signal to the radiation source control device 14. The irradiation switch 15 is a two-stage switch. When the first stage is pressed, a warm-up start signal for starting warm-up of the X-ray source 13 is input, and when the second stage is pressed, the X-ray source 13 is irradiated. An irradiation start signal for starting is input.

  The X-ray imaging apparatus 12 includes an electronic cassette 21, an imaging table 22, an imaging control apparatus 23, and a console 24. The electronic cassette 21 includes an FPD 31 (see FIG. 3) and a portable housing 26 (see FIG. 2) that accommodates the FPD 31, and is irradiated from the X-ray source 13 and passes through a subject (subject) H. An X-ray image detection apparatus that detects an X-ray image by receiving an irradiation of a line. The casing 26 of the electronic cassette 21 has a flat box shape. The casing 26 has an outer size conforming to the international standard ISO 4090: 2001 similar to a cassette for film or IP of a half-cut size (383.5 mm × 459.5 mm), and has an X-ray incident surface 26a ( The planar shape of the back surface on the opposite side to the front surface (see FIG. 2) is a rectangle.

  The imaging table 22 has a slot in which the electronic cassette 21 is detachably attached, and holds the electronic cassette 21 with an incident surface on which X-rays are incident facing the X-ray source 13. The electronic cassette 21 can be attached to a film cassette or an IP cassette photographing stand because the size of the casing 26 is almost the same as that of the film cassette or the IP cassette. As the imaging table 22, a standing imaging table for imaging the subject H in a standing posture is illustrated, but of course, a standing imaging table for imaging the subject H in a lying posture may be used.

  The imaging control device 23 is connected to the electronic cassette 21 so as to be communicable by a wired method or a wireless method, and controls the electronic cassette 21. Specifically, the imaging conditions are transmitted to the electronic cassette 21 to set the processing conditions of the signal processing of the FPD 31 (such as the gain of an integrating amplifier that amplifies the voltage corresponding to the signal charge), and the X-ray source 13 The X-ray source 13 and the FPD 31 are synchronously controlled by receiving a synchronization signal for synchronizing the irradiation timing of the FPD 31 and the accumulation operation of the FPD 31 from the X-ray generator 11 and transmitting it to the electronic cassette 21. Further, the imaging control device 23 receives the image data output from the electronic cassette 21 and transmits it to the console 24.

  The console 24 receives an input of an examination order including information such as a patient's sex, age, imaging region, and imaging purpose, and displays the examination order on a monitor. The examination order is input from an external system that manages patient information such as HIS (Hospital Information System) and RIS (Radiation Information System) and examination information related to radiation examination. Alternatively, it is manually input by an operator such as an engineer. The operator confirms the contents of the inspection order on the monitor, and selects an imaging condition corresponding to the contents through the operation screen of the console 24. The selected shooting condition is transmitted to the shooting control device 23.

  The console 24 performs image processing on the X-ray image data transmitted from the imaging control device 23. The processed X-ray image is displayed on the monitor of the console 24, and the X-ray image data is stored in a data storage device such as a hard disk or memory in the console 24 or an image storage server connected to the console 24 via a network. Stored.

  As shown in FIG. 2, the electronic cassette 21 is removed from the imaging table 22 for imaging sites that are difficult to image with the electronic cassette 21 attached to the imaging table 22, such as the hand and foot of the subject H. Used. When the hand of the subject H is an imaging region, the electronic cassette 21 is placed on a bed or a table with the incident surface 26a on which an X-ray is incident, which is one surface of the outer surface of the housing 26, facing upward, for example. Placed. The hand of the subject H is placed on the approximate center of the incident surface 26a and photographing is performed. Most part of the entrance surface 26a except the outer edge is composed of a transmission plate 27 that transmits X-rays. When the electronic cassette 21 is removed from the imaging table 22, the transmission plate 27 and the subject H are used. Imaging is performed by directly contacting the imaging part.

  In FIG. 3, an FPD 31 drives a detection panel 35 having a detection surface 38 composed of a pixel array in which a plurality of pixels 37 for accumulating signal charges according to the amount of incident X-rays are arranged, and drives the pixels 37 to generate signal charges. Operation of the FPD 31 by controlling the gate driver 39 for controlling the reading of the signal, the signal processing circuit 40 for converting the signal charge read from the pixel 37 into digital data and outputting it, and the gate driver 39 and the signal processing circuit 40. And a control circuit 41 for controlling. The plurality of pixels 37 are two-dimensionally arranged in a matrix of G1 to Gn rows (x direction) × D1 to Dm columns (y direction) at a predetermined pitch.

  The FPD 31 is an indirect conversion type that converts X-rays into visible light, photoelectrically converts visible light, and accumulates signal charges. The detection panel 35 is a photoelectric conversion panel that photoelectrically converts visible light by the pixels 37, and a scintillator 61 that converts X-rays into visible light on the detection surface 38 so as to face the entire surface (see FIGS. 4 and 5). Reference) is arranged. The scintillator 61 is made of a phosphor such as CsI (cesium iodide) or GOS (gadolinium oxysulfide). The scintillator 61 is formed by a method of adhering a sheet coated with a phosphor on a support with an adhesive, or depositing a phosphor on the detection surface 38.

  The pixel 37 includes a photodiode 42 that is a photoelectric conversion element that generates charges (electron-hole pairs) upon incidence of visible light, and a capacitor that accumulates the charges generated by the photodiode 42, and a thin film transistor (TFT) as a switching element. 43. The detection panel 35 is a TFT active matrix substrate in which pixels 37 are formed on an insulating substrate such as a glass substrate 71 (see FIG. 5).

  The photodiode 42 has a structure in which a semiconductor layer (for example, PIN type) such as a-Si (amorphous silicon) and an upper electrode and a lower electrode are arranged above and below the semiconductor layer. In the photodiode 42, the TFT 43 is connected to the lower electrode, the bias line 47 is connected to the upper electrode, and a bias voltage is applied from the bias power supply 48. Since an electric field is generated in the semiconductor layer by applying a bias voltage, charges (electron-hole pairs) generated in the semiconductor layer by photoelectric conversion are applied to the upper and lower electrodes, one having a positive polarity and the other having a negative polarity. The electric charge is accumulated in the capacitor.

  The TFT 43 has a gate electrode connected to the scanning line 44, a source electrode connected to the signal line 46, and a drain electrode connected to the photodiode 42. The scanning lines 44 and the signal lines 46 are wired in a lattice pattern. The scanning lines 44 are the number of rows of the pixels 37 in the detection surface 38 (n rows), and the signal lines 46 are the number of columns of the pixels 37 (m. Each column is wired. The scanning line 44 is connected to the gate driver 39, and the signal line 46 is connected to the readout circuit 49.

  The readout circuit 49 includes an integration amplifier that converts the signal charge read from the detection panel 35 into a voltage signal, and a multiplexer that sequentially switches the columns of the pixels 37 in the detection surface 38 and sequentially outputs the voltage signals column by column. Become. The voltage signal read by the reading circuit 49 is converted into digital data by the A / D conversion circuit 51 and written as digital image data in the memory 52.

  As shown in FIGS. 4 and 5, the housing 26 forms an incident surface 26 a, and includes a front surface portion 56 that covers the panel unit 62 including the detection panel 35 and the scintillator 61 from the front surface, and a back surface portion 57 that covers the back surface. Become. The front surface portion 56 includes a transmission plate 27 and a frame body 56a in which an opening to which the transmission plate 27 is attached is formed. The transmission plate 27 is made of a carbon material that is lightweight, has high rigidity, and has high X-ray permeability. The frame body 56a is made of, for example, a resin. The back surface portion 57 is formed of a metal such as stainless steel. On the back side of the panel unit 62, a base plate 63 and circuit boards 66 to 69 are arranged in this order.

  The panel unit 62 is arranged in an orientation in which the scintillator 61 and the detection panel 35 are positioned in this order from the incident surface 26 a side of the housing 26. Circuit boards 66 to 69 are attached to the base plate 63. The base plate 63 is made of stainless steel, for example.

  The circuit board 66 is a circuit board on which circuit elements constituting the gate driver 39 that drives the TFT of the detection panel 35 are formed. The circuit board 67 is a circuit board on which circuit elements constituting the A / D conversion circuit 51 are formed. The circuit board 68 is a circuit board on which circuit elements constituting the control circuit 41 are formed. The circuit board 69 is a circuit board on which circuit elements constituting a power circuit (AC-DC converter, DC-DC converter, etc.) are formed.

  The circuit board 66 and the circuit board 67 are connected to the detection panel 35 by flexible cables 76 and 77, respectively. TCP (tape carrier package) type IC chips 78 and 79 are mounted on the flexible cables 76 and 77, respectively. The IC chip 78 includes a shift register for sequentially shifting the gate pulse in units of rows of the pixels 37, and constitutes the gate driver 39 together with the circuit elements formed on the circuit board 66. The IC chip 79 is an ASIC that constitutes the readout circuit 49.

  As shown in FIG. 2, unlike the stationary type, the electronic cassette 21 may be photographed by bringing a photographing part such as the hand of the subject H into contact with the transmission plate 27, so that depending on the body temperature of the subject H, The temperature of the transmission plate 27 rises and the heat is easily transferred into the housing 26 that houses the detection panel 35. Since the sensitivity and dark current characteristics of the photodiode 42 have temperature dependence, it is not preferable that heat is transferred from the outside of the housing 26 to the inside of the housing 26.

  In addition to satisfying the basic performance of the transmission plate, which is lightweight, high in rigidity, and high in X-ray transmission, the transmission plate 27 uses a carbon material. Is difficult to be transmitted to the inside of the housing 26.

  As shown in FIG. 6, the transmission plate 27 has a laminated structure of a first layer 81 to a third layer 83 in which each layer is made of a carbon sheet. The first layer 81 that is the outermost layer constituting the outer surface of the casing 26 and the third layer 83 that is the innermost layer are PITCH-based carbon sheets formed of a PITCH-based carbon material formed of PITCH-based carbon fibers. The second layer 82 serving as an intermediate layer is a PAN-based carbon sheet formed of a PAN-based carbon material formed of PAN-based carbon fibers. The transmission plate 27 has a sandwich structure in which the upper and lower sides of the PAN-based carbon sheet are sandwiched between the PITCH-based carbon sheets. The carbon sheets of the first layer 81, the second layer 82, and the third layer 83 are formed by laminating and integrating them by a heat and pressure method (autoclave molding method) or a bonding method such as fusion or adhesion. The

  The PITCH-based carbon fiber is a carbon fiber obtained by carbonizing a PITCH precursor (pitch fiber obtained using coal tar or heavy petroleum as a raw material), and the PAN-based carbon fiber is a polymerized PAN precursor (polymerized acrylonitrile). This is a carbon fiber obtained by carbonizing an acrylic fiber made from polyacrylonitrile. PITCH-based carbon fibers have the advantage of higher thermal conductivity than PAN-based carbon fibers, while PAN-based carbon fibers are more rigid and less expensive than PITCH-based carbon fibers. Has the advantage.

  Therefore, by using a PITCH-based carbon sheet having a higher thermal conductivity than the PAN-based carbon sheet for the first layer 81 that is the outermost layer, a part of the transmission plate 27 such as a contact portion with the subject H can be obtained. Even when heat is applied to the portion and the temperature rises, the heat can be quickly diffused into the first layer 81. Since the 1st layer 81 is located in the outer surface of the housing | casing 26, since it is exposed to air | atmosphere, the heat dissipation effect is also high. Therefore, heat is not easily transmitted to the inside of the housing 26.

  The PITCH-based carbon sheet used for the first layer 81 has a thermal conductivity of 150 W / mK or more. When the experiment was conducted assuming that the subject H is in contact with the transmission plate 27 and the thermal conductivity is 150 W / mK or more, an experimental result is obtained that the operation of the detection panel 35 is not affected. It was.

  Further, by using the same PITCH-based carbon sheet as that of the first layer 81 for the third layer 83, the warp of the transmission plate 27 can be prevented. Since the expansion coefficient differs between the PITCH-based carbon sheet and the PAN-based carbon sheet, warping is prevented by adopting a sandwich structure in which the PAN-based carbon sheet is sandwiched between the same types of PITCH-based carbon sheets having the same expansion coefficient from both sides.

  Below, the permeation | transmission board of Examples 1 and 2 using the PITCH type | system | group carbon sheet whose heat conductivity is 150 W / mK or more, and the permeation | transmission board of the comparative example using the carbon sheet whose heat conductivity is less than 150 W / mK are shown. The experimental results evaluated under predetermined conditions are shown.

  As shown in Table 1 below, each of the transmission plates of Examples 1 and 2 and Comparative Example is a flat prepreg in which a carbon fiber sheet in which carbon fibers are aligned in one direction is impregnated with a matrix resin as a base material. Eight sheets are laminated, and one transmission plate is produced from these eight prepregs by an autoclave molding method. The molding conditions of the autoclave molding were as follows: the temperature was raised from room temperature to 150 ° C. at a rate of temperature rise of 2 ° C./min, and the mixture was allowed to cool at 150 ° C. for 2 hours, followed by natural cooling.

  The direction of the carbon fiber of the prepreg of each layer from the first layer to the eighth layer is common to all of Examples 1, 2 and Comparative Example, and the first layer is 0 °, and the second layer is perpendicular to the first layer. (90 °) The third layer is the same 90 ° as the second layer, the fourth and fifth layers are 0 °, the sixth layer is 90 °, the seventh layer is 90 °, and the eighth layer is 0 °. It is.

  As shown in Table 1, the breakdown of the eight-layer prepregs of Examples 1 and 2 is four PAN-based prepregs using PAN-based carbon fibers and four PITCH-based prepregs using PITCH-based carbon fibers, In Examples 1 and 2, a PAN-based carbon sheet in which four PAN-based prepregs are stacked is used as an intermediate material, and carbon sheets in which two PITCH-based prepregs are stacked are disposed above and below the intermediate material. The two PITCH prepregs of the first layer and the second layer constitute the PITCH carbon sheet of the first layer 81 (see FIG. 7), and the four PAN prepregs from the third layer to the sixth layer, The PAN-based carbon sheet of the second layer 82 (see FIG. 7) is configured, and the two PITCH-based prepregs of the seventh and eighth layers configure the PITCH-based carbon sheet of the third layer 83 (see FIG. 7). .

The PAN prepreg is common to Example 1 and Example 2, and uses a product number TR380G125 (hereinafter abbreviated as TR) manufactured by Mitsubishi Rayon. TR is a PAN-based carbon fiber using a product number TR50 manufactured by Mitsubishi Rayon, which has a fiber basis weight indicating the density of the fiber of 125 g / m ² and a thermal conductivity of 10 W / mK.

The PITCH prepreg differs between Example 1 and Example 2. The PITCH prepreg of Example 1 uses a product number URP380E125 (hereinafter abbreviated as URP) manufactured by Mitsubishi Rayon. URP is a PITCH-based carbon fiber using a product number XN60 made of Nippon Graphite Fiber having a fiber basis weight of 125 g / m ² and a thermal conductivity of 180 W / mK. The PITCH prepreg of Example 2 uses a product number WRP380E125 (hereinafter abbreviated as WRP) manufactured by Mitsubishi Rayon. WRP uses, as a PITCH carbon fiber, a product number XN80 manufactured by Nippon Graphite Fiber having a fiber basis weight of 125 g / m ² and a thermal conductivity of 320 W / mK.

  In the comparative example, the same TR as that of the PAN-based prepreg used in Examples 1 and 2 was used for all eight prepregs.

  The transmission plates of Examples 1 and 2 and the comparative example were evaluated for heat dissipation in the following manner. The evaluation method is to suspend the transmission plates of Examples 1 and 2 and Comparative Example to be suspended in an environment where the temperature is stable, touch the back of the transmission plate with the tester's hand, warm it for about 10 seconds, and release the hand. Immediately after this, the thermal distribution on the surface of the transmission plate was photographed with a thermography camera to confirm the thermal diffusion effect. FIG. 8 shows the thermographic measurement results of Example 2 and Comparative Example, and Table 2 below summarizes the evaluation results of Examples 1 and 2 and Comparative Example.

  As shown in FIG. 8, in the measurement result of Example 2, the palm shape does not remain and the part corresponding to the palm is totally blurred. This indicates that the heat of the palm in contact with the rear surface of the transmission plate is diffused in the plane of the transmission plate and is not easily transmitted to the opposite surface. In the measurement result of Example 2, the maximum temperature is also 28 ° C., which is within 30 ° C. From these measurement results, it can be seen that Example 2 has good thermal diffusibility and heat dissipation.

  Example 1 has a lower thermal conductivity than Example 2, but the thermal conductivity is 150 W / mK or higher, so as shown in Table 2, the measurement results of Example 1 are the same as in Example 2. Good results were obtained in terms of thermal diffusivity and heat dissipation.

  On the other hand, in the measurement result of the comparative example, as shown in FIG. 8, the shape of the palm and the high temperature portion where the contact pressure with the transmission plate such as the fingertip is high in the palm are clearly reflected. This indicates that the heat of the palm in contact with the rear surface of the transmission plate is transmitted to the opposite surface without being diffused in the plane of the transmission plate. Moreover, in the measurement result of the comparative example, the maximum temperature also reaches 35 ° C., and exceeds 30 ° C. From these measurement results, it was confirmed that the comparative example was inferior in terms of thermal diffusibility and heat dissipation compared to Examples 1 and 2.

  As described above, by using a PITCH carbon sheet having a thermal conductivity of 150 W / mK or more for the outermost layer of the transmission plate 27, the heat diffusibility and heat dissipation of the transmission plate 27 are improved. Heat is not easily transmitted to the inside.

  Further, in the above embodiment, the configuration of the transmission plate 27 has been described with an example of a three-layer configuration from the first layer 81 to the third layer 83, but may be four or more layers. Further, the number of laminated prepregs constituting each of the first layer 81 to the third layer 83 shown in the above embodiment is one example, and may be equal to or less than the number of laminated layers in the above embodiment. Further, another layer may be inserted between each of the first layer 81 to the third layer 83. Further, in the present invention, a PITCH carbon sheet may be used as the outermost layer of the transmission plate 27. For example, the second layer 82 and the third layer 83 are not provided, and the PITCH carbon sheet is formed on the support. Just be there. The support is only required to be X-ray transparent, and may be a carbon material or other material. However, the carbon material is preferably a carbon material because it satisfies the basic performance of an X-ray imaging cassette that is lightweight and has high rigidity and good X-ray permeability.

  In the above embodiment, the case where the subject H comes into contact with the transmission plate 27 and heat is transmitted to the transmission plate 27 due to body temperature has been described as an example. However, since the transmission plate 27 constitutes the outer surface of the housing 26, In addition to the body temperature of the examiner H, there is a thermal disturbance depending on the environment in which the housing 26 is placed. Even when the temperature locally rises in the plane of the transmission plate 27 due to a thermal disturbance other than the body temperature of the subject H, according to the present invention, the same effect as described in the above embodiment can be obtained. is there.

  In the said embodiment, although demonstrated in the form which comprised the front part of the housing | casing with the permeation | transmission board and the frame, the whole surface of the front part of a housing | casing may be comprised with the permeation | transmission board.

  In the above embodiment, X-rays have been described as an example of radiation. However, the present invention may use radiation other than X-rays, such as γ-rays. The present invention is not limited to the above-described embodiment, and various modifications can be made without departing from the spirit of the invention.

DESCRIPTION OF SYMBOLS 10 X-ray imaging system 21 Electronic cassette 26 Case 27 Transmission plate 31 FPD (radiation image detector)
35 Detection panel (detection unit)
37 pixels 38 detection surface 61 scintillator 81 first layer 82 second layer 83 third layer

Claims (2)

A radiation image detector for detecting a radiation image of the subject in response to radiation that has passed through the subject;
A housing for housing the radiation image detector;
In the housing, a transmission plate constituting an incident surface for transmitting the radiation and entering the radiation image detector, and a first layer serving as an outermost layer constituting the outer surface of the housing is a heat A transmission plate made of a PITCH-based carbon material formed of a PITCH-based carbon fiber having a conductivity of 150 W / mK or more ,
2. The radiographic electronic cassette according to claim 1, wherein the transmission plate is made of a PAN-based carbon material in which a second layer located on the inner side of the first layer is formed of a PAN-based carbon fiber . The transmission plate has a sandwich structure in which a third layer located on the inner side of the second layer is composed of the PITCH-based carbon material, and the second layer is sandwiched by the PITCH-based carbon material from both sides. 2. The electronic cassette for radiography according to claim 1 , wherein the electronic cassette is provided.