JP2014066555A - Radiation detector - Google Patents

Abstract

PROBLEM TO BE SOLVED: To prevent fragments of a broken housing of a radiation detector from scattering when it is broken without lowering compatibility to a human body.SOLUTION: A radiation detector 30 comprises: a radiation detection panel 21; and a housing 22. The radiation detection panel 21 detects radiation. The housing 22 internally houses the radiation detection panel 21, a support member 20 for supporting it, and a circuit board 23 on which a portion of an electric circuit, for processing signals of the radiation detection panel 21, and the like are mounted. An inner surface of the housing 22 is covered with a film-like scattering prevention material 19. The scattering prevention material 19 is made of a viscoelastic material such as rubber or silicone resin or an adhesive material. The scattering prevention material 19 is applied to the housing 22 in the form of a sheet or by coating.

Description

  Embodiments generally relate to radiation detection devices.

  Conventionally, an X-ray image detector using an active matrix has attracted much attention as a diagnostic detector for detecting radiation, particularly X-rays. By applying X-rays to a planar detector, an X-ray image or a real-time X-ray image is output as a digital signal. Since it is a solid state detector, it is extremely promising in terms of image quality and stability. For this reason, many universities and manufacturers have been engaged in research and development.

  In the early stages of practical use, it was developed for chest and general radiography that collects still images with a relatively large dose, and has recently been commercialized. Commercialization is also progressing for applications in the circulatory and digestive fields where it is necessary to clear higher technical hurdles and realize real-time video of 30 frames per second under fluoroscopic dose. In the future, not only conventional X-ray image detectors that are limited in place as inspection systems, but also X-ray image detectors that can carry X-ray image detectors and perform X-ray image diagnosis where needed In addition, products that can perform auxiliary imaging of X-ray image detectors in fixed inspection systems are important development items.

  Radiation detection devices that detect radiation, particularly X-rays, are used in a wide range of fields such as industrial nondestructive inspection, medical diagnosis, and structural research.

  Among radiation detection apparatuses, a radiation detection apparatus including a radiation detection panel in which a phosphor layer that converts radiation into light is directly formed on a photodetector is known as a high-sensitivity and high-definition apparatus. This photodetector has a photoelectric conversion element section in which a plurality of photosensors and TFTs (Thin Film Transistors) as switching elements are two-dimensionally arranged on a glass substrate. The switching element of each pixel is connected to a gate line representing a row and a signal line representing a column. The gate lines and the signal lines are arranged in a grid pattern and are connected to each pixel arranged in the grid pattern.

  By laminating a phosphor that converts X-rays into visible light on a planar photodetector, X-rays incident from the outside are converted into visible light inside the phosphor, and the generated visible light is detected by planar light. Incident light. At this time, visible light incident on the photodiode inside the planar photodetector is converted into electric charge by the photodiode. This electric charge is accumulated in the photodiode or in the capacitive element connected in parallel.

  The X-ray image information converted into electric charge is transmitted to the outside of the substrate through a switching element (TFT) connected to the photodiode. When the potential of the gate line changes, the TFT connected to the gate line whose potential has changed becomes conductive. The electric charge accumulated in the photodiode or the capacitive element connected to the TFT in the conductive state is output to the outside through the TFT. The charge output to the outside is output to the outside of the glass substrate through a signal line connected to the TFT.

  The charge signal output to the outside of the glass substrate is input to the integrating amplifier connected to each signal line. The charge information input to the integrating amplifier is amplified, converted into a potential signal, and output. The potential signal output from the integrating amplifier is converted into a digital value by an analog / digital converter, and finally edited as an image signal and output to the outside of the X-ray image detector. The radiation detection panel is supported on one surface of a plate-like support member, and a circuit board that drives the radiation detection panel is supported on the other surface of the support member. These radiation detection panel and circuit board are electrically connected by a flexible circuit board.

  The housing of the radiation detection apparatus is configured by protecting the support member that supports the radiation detection panel and the circuit board connected to the radiation detection panel from the outside and combining metal and resin parts so as to be integrated. In particular, in an X-ray image detector that can be carried, it is thin and lightweight, and can be replaced with a film medium that has been incorporated into a conventional cassette and has taken an X-ray image.

JP 2002-186604 A JP 2010-127882 A JP 2009-104042 A

  When constructing a thin and lightweight casing for portability and film cassette replacement, the X-ray detector receives various external forces. For this reason, even if the casing is dropped unintentionally or a load is applied, it is necessary to keep the safety of the casing components so as not to harm the user as a minimum. If the casing exterior parts are damaged and scattered, there is a risk of harm to the user. In addition, the portable X-ray detector, unlike the X-ray detector incorporated in the conventional X-ray diagnostic system, touches the patient directly at the time of X-ray imaging, so that the casing exterior component contacts the human body. However, it is necessary that the material does not cause harm, and the material of the exterior component is limited.

  Then, embodiment aims at suppressing scattering of the fragment when the housing | casing of a radiation detection apparatus is damaged, without reducing a human body compatibility.

  In order to achieve the above object, a radiation detection apparatus according to an embodiment includes a radiation detection panel that detects radiation, a housing that houses the radiation detection panel, and a film that is attached to at least a part of the inner surface of the housing. And an anti-scattering material.

1 is a block diagram of a radiation detection apparatus according to a first embodiment. It is a typical perspective view of the radiation detection panel by 1st Embodiment. It is a circuit diagram of the image detection part by 1st Embodiment. It is a longitudinal cross-sectional view of the radiation detection apparatus by 1st Embodiment. It is sectional drawing of the radiation detection apparatus by the modification of 1st Embodiment. It is a perspective view of the radiation detection apparatus by the modification of 1st Embodiment. It is a longitudinal cross-sectional view of the radiation detection apparatus by 2nd Embodiment. It is a partial expanded cross-sectional view of the radiation detection apparatus by 2nd Embodiment. It is a perspective view of the radiation detection apparatus by the modification of 2nd Embodiment.

Hereinafter, radiation detection devices according to some embodiments will be described with reference to the drawings. In addition, the same code | symbol is attached | subjected to the same or similar structure, and the overlapping description is abbreviate | omitted.
[First Embodiment]

  FIG. 1 is a block diagram of the radiation detection apparatus according to the first embodiment. FIG. 2 is a schematic perspective view of the radiation detection panel according to the first embodiment. FIG. 3 is a circuit diagram of the image detection unit according to the first embodiment.

  The radiation detection device 30 has a radiation detection panel 21. The radiation detection panel 21 converts incident X-rays into electrical signals.

  A plurality of integration amplifiers 33 and a plurality of gate drivers 32 are connected to the radiation detection panel 21. A row selection circuit 35 is connected to the gate driver 32. An A / D converter 34 is connected to the integrating amplifier 33. The A / D converter 34 is connected to an image composition circuit 36.

  When the gate driver 32 receives a signal from the row selection circuit 35, the gate driver 32 sequentially changes the voltages of many gate lines connected to the radiation detection panel 21. The integrating amplifier 3 amplifies and outputs a very small charge signal output from the radiation detection panel 21. A row selection circuit 35 is connected to the gate driver 32 and sends a signal to the corresponding gate driver 32 according to the scanning direction of the X-ray image.

  The radiation detection panel 21 includes a fluorescence conversion film 38 and an image detection unit 12. Incident X-rays 37 incident on the fluorescence conversion film 38 are converted into fluorescence inside the fluorescence conversion film 38. The fluorescence generated in the fluorescence conversion film 38 reaches the surface of the image detection unit 12.

  The image detection unit 12 has a holding substrate 11 mainly composed of a glass substrate. On the holding substrate 11, the TFT circuit layer 10 and the photodiode 16 are formed in layers. A visible light image incident on the radiation detection panel 21 from the outside is converted into image information by an electrical signal in the image detection unit 12.

  Fine pixels are formed in a lattice pattern on the surface of the image detection unit 12. Each pixel includes a thin film transistor 14, a capacitor 15, and a photodiode 16. A gate line 13 and a signal line 17 are connected to each pixel.

  Next, the operation of the radiation detection panel 21 will be described.

  In the initial state, the detected charge is stored in the capacitor 15, and a reverse bias voltage is applied to the photodiode 16 connected in parallel. The voltage at this time is the same as the voltage applied to the signal line 17.

  Since the photodiode 16 is a kind of diode, even if a reverse bias voltage is applied, almost no current flows. Therefore, the electric charge stored in the capacitor 15 is held without decreasing.

  When incident X-rays 37 are incident on the fluorescence conversion film 38 in this situation, high-energy X-rays are converted into many low-energy visible lights inside the fluorescence conversion film 38. Part of the fluorescence generated inside the fluorescence conversion film 38 reaches the photodiode 16 disposed on the surface of the image detection unit 12.

  Fluorescence incident on the photodiode 16 is converted into charges composed of electrons and holes inside the photodiode 16 and reaches both terminals of the photodiode 16 along the direction of the electric field applied by the capacitor 15. Thus, the current flowing through the photodiode 16 is observed.

  The current flowing through the photodiode 16 generated by the incidence of the fluorescence flows into the capacitor 15 connected in parallel, and acts to cancel the charge stored in the capacitor 15. As a result, the electric charge stored in the capacitor 15 decreases, and the potential difference generated between the terminals of the capacitor 15 also decreases compared to the initial state.

  The gate line 13 is connected to a specific gate driver 32. The gate driver 32 changes the potential of the multiple gate lines 13 in order. At a specific time, the gate driver 32 has only one gate line 13 whose potential is changing. Between the source and drain terminals of the thin film transistor 14 connected to the gate line 13 whose potential has changed, the state changes from an insulated state to a conductive state.

  A specific voltage is applied to each signal line 17. This voltage is applied to the capacitor 15 connected through the source terminal and the drain terminal of the thin film transistor 14 connected to the gate line 13 whose potential has changed.

  Since the capacitor 15 is in the same potential state as that of the signal line 17 in the initial state, if the amount of charge in the capacitor 15 has not changed from the initial state, no charge transfer from the signal line 17 occurs in the capacitor 15. However, in the capacitor 15 connected in parallel with the photodiode 16 in which the fluorescence generated inside the fluorescent film 38 is incident by the incident X-ray 37 from the outside, the charge stored inside is reduced, and the initial state The electric potential of is changed. For this reason, the charge moves from the signal line 17 through the thin film transistor 14 in the conductive state, and the amount of charge stored in the capacitor 15 returns to the initial state. The amount of charge that has moved becomes a signal that flows through the signal line 17 and is transmitted to the outside.

  The signal line 17 is connected to the integrating amplifier 3. The signal lines 17 are connected to the integrating amplifiers 3 corresponding to the signal lines 17 on a one-to-one basis. The current flowing through the signal line 17 is input to the corresponding integrating amplifier 3. The integrating amplifier 3 integrates the current flowing within a predetermined time and outputs a voltage corresponding to the integrated value to the outside.

  By performing this operation, the amount of charge flowing through the signal line 17 within a certain time can be converted into a voltage value. As a result, the charge signal generated inside the photodiode 16 corresponding to the intensity distribution of the fluorescence generated inside the fluorescence conversion film 38 by the incident X-ray 37 is converted into potential information by the integrating amplifier 3.

  The potential generated by the integrating amplifier 33 is sequentially converted into a digital signal by the A / D converter 34. The signals that have become digital values are sequentially arranged in accordance with the rows and columns of pixels arranged in the image detection unit 12 inside the image composition circuit 36, and are output to the outside as image signals.

  By continuously performing these operations, the X-ray image information incident from the outside is converted into image information by an electric signal and output to the outside. Image information based on an electrical signal output to the outside can be easily imaged by a normal display device, and an X-ray image can be observed as an image by visible light by the image.

  FIG. 4 is a longitudinal sectional view of the radiation detection apparatus according to the first embodiment.

  The radiation detection device 30 includes a radiation detection panel 21, a plate-like support member 20, a circuit board 23, a flexible circuit board 18, and a housing 22. The radiation detection panel 21 is housed inside the housing 22. The housing 22 is a rectangular parallelepiped box. The support member 20 supports the radiation detection panel 21. The support member 20 is fixed to the housing 22 by a support column 41.

  On the circuit board 23, an electric circuit such as a row selection circuit 35 that drives the radiation detection panel 21 and an electric circuit such as an integration amplifier 3 that processes an electric signal output from the radiation detection panel 21 are mounted. There may be one or more circuit boards 23. The radiation detection panel 21 and the circuit board 23 are electrically connected by the flexible circuit board 18.

  The housing 22 is a rectangular parallelepiped box having a radiation 37 incident surface and a back surface parallel thereto. The housing 22 is formed of, for example, a mixed material or a single material of polycarbonate and ABS resin, carbon fiber reinforced plastic (CFRP), or the like. A film-like anti-scattering material 19 is attached to the inside of the housing 22. The scattering prevention material 19 is formed of a viscoelastic material such as rubber or silicone resin or an adhesive material. The anti-scattering material 19 is more ductile than the constituent material of the housing 22. Further, the anti-scattering material 19 is firmly attached to the inner surface of the housing 22 by being bonded to the housing 22 or directly applied to the housing 22.

  When such a case 22 is used, even if an external force is applied to the case 22 and a part of the case 22 is damaged, a part of the damaged case 22 is not attached to the scattering prevention material 19 and is not damaged. It is connected with the part of and is not separated more than a certain distance. That is, the fragments of the casing 22 are not scattered, and a shape that does not harm the patient / user in the vicinity of the radiation detection device 30 can be maintained.

  In addition, it is necessary to select a material that is confirmed to be biocompatible so as not to harm the patient's human body due to an allergic reaction or the like for a portion that comes into contact with the human body when using the material of the outer surface of the housing 22 or a coating material. . On the other hand, since the scattering prevention material 19 is disposed inside the housing 22, the radiation detector and the human body do not come into contact with each other during radiography. Therefore, by disposing the scattering prevention material 19 inside the housing 22, it is not necessary to consider biocompatibility of the scattering prevention material 19. That is, the choice of the material used for the scattering prevention material 19 can be expanded without increasing the risk to the patient's human body.

  FIG. 5 is a cross-sectional view of a radiation detection apparatus according to a modification of the first embodiment. FIG. 6 is a perspective view of a radiation detection apparatus according to this modification.

  In this modified example, the scattering prevention material 19 is not attached to the entire inside of the housing 22 but is attached to a part of the housing 22. For example, the scattering prevention material 19 is selectively attached to the inside of the casing 22 in the vicinity of the corner portion 51. The corner portion 51 of the housing 22 is a portion that easily collides with the floor or the like when the radiation detection device 30 is dropped. For this reason, there is a high possibility that a large stress is generated due to a collision at the corner portion 51 of the housing 22, and the stress is likely to be concentrated and easily damaged. Therefore, by applying the anti-scattering material 19 to this portion, the possibility of the fragments of the housing 22 being scattered can be suppressed.

  Further, the scattering prevention material 19 may be attached to the inside of the vicinity of the ridge line portion 52 of the housing 22. The ridge line portion 52 is also a portion where stress is easily concentrated and easily damaged. Therefore, the possibility of scattering of the fragments of the housing can be suppressed by attaching the anti-scattering material 19 to this portion.

Thus, by applying the anti-scattering material 19 to a portion where the possibility of breakage of the housing 22 is high, the amount of material used can be reduced while suppressing the possibility of debris scattering of the housing 22. In addition, when the plurality of sheet-like anti-scattering materials 19 are bonded to the housing 22 with an adhesive, a material smaller than that covering the entire inside of the housing 22 can be used. For this reason, the pasting work is easy.
[Second Embodiment]

  FIG. 7 is a longitudinal sectional view of the radiation detection apparatus according to the second embodiment. FIG. 8 is a partially enlarged cross-sectional view of the radiation detection apparatus according to the second embodiment.

  In the present embodiment, the housing 22 includes an incident surface cover 24, a side cover 27, a back cover 26, and a corner cover 28. The corner cover 28 forms four ridge lines perpendicular to the incident surface cover 24 and the back cover 26 of the housing 22 and the vicinity thereof. Side covers 27 perpendicular to the incident surface cover 24 and the back cover 26 are arranged at positions sandwiched between the corner covers 28.

  For each member, an appropriate material is selected from the required functions. The corner cover 28 is formed of polycarbonate, ABS resin, or the mixed material described on the left. The incident surface cover 24 and the back cover 26 are formed of a material having higher strength than the corner cover 28 such as carbon fiber reinforced plastic (CFRP). The side cover 27 is formed of the same material as the corner cover 28, for example. You may form the window part into which the radiation of the entrance plane cover 24 injects with the material different from the circumference | surroundings.

  The scattering prevention member 19 is attached to the inner surface of the corner cover 28. Further, the scattering prevention member 19 may be attached so as to straddle the corner cover 28, the incident surface cover 24, the back cover 26, or the side cover 27.

  A flat plate having a relatively large area is required on the surface of the housing 22 that is parallel to the radiation incident surface of the radiation detection panel 21. Therefore, in this embodiment, CFRP having high strength is used for the flat entrance surface cover 24 and the back cover 26.

  On the other hand, it is difficult to form a complicated shape with a composite material of fibers such as CFRP and a resin. Therefore, the corner cover 28 is formed of polycarbonate, ABS resin, or a mixed material thereof. For this reason, the corner cover 28 can be formed in a more complicated shape than a flat plate by injection molding or the like.

  However, it is difficult to increase the strength of a resin material such as polycarbonate as compared with a composite material such as CFRP. Therefore, in the present embodiment, the anti-scattering material 19 is attached to the inner surface of the corner cover 28 where the drop impact is likely to increase when the housing 22 is dropped, so that the fragments are not scattered even if it is damaged. . Furthermore, the thickness of the corner cover 28 may be thicker than that of the incident surface cover 24 or the back cover 26 as necessary.

  FIG. 9 is a perspective view of a radiation detection apparatus according to a modification of the second embodiment.

In this modification, instead of the side cover 27 and the corner cover 28 (see FIGS. 7 and 8), a side corner cover 25 in which these are integrated is used. As described above, the portion perpendicular to the incident surface cover 24 of the housing 22 may be formed using a member divided into one or a plurality of parts from the viewpoint of function and assemblability. In the case where a portion where damage is likely to occur is constituted by a plurality of members, the use as a product can be continued by partially exchanging and repairing the parts when damage occurs.
[Other embodiments]

  Although several embodiments of the present invention have been described, these embodiments are presented by way of example and are not intended to limit the scope of the invention. These novel embodiments can be implemented in various other forms, and various omissions, replacements, and changes can be made without departing from the scope of the invention. These embodiments and modifications thereof are included in the scope and gist of the invention, and are included in the invention described in the claims and the equivalents thereof.

DESCRIPTION OF SYMBOLS 10 ... TFT circuit layer, 11 ... Holding substrate, 12 ... Image detection part, 13 ... Gate line, 14 ... Thin-film transistor, 15 ... Condenser, 16 ... Photodiode, 17 ... Signal line, 18 ... Flexible circuit board, 19 ... Prevention of scattering 20 ... support member, 21 ... radiation detection panel, 22 ... casing, 23 ... circuit board, 24 ... incident surface cover, 25 ... side / corner cover, 26 ... back cover, 27 ... side cover, 28 ... corner cover , 30 ... Radiation detection device, 32 ... Gate driver, 33 ... Integration amplifier, 34 ... A / D converter, 35 ... Row selection circuit, 36 ... Image composition circuit, 37 ... Incident X-ray, 38 ... Fluorescence conversion film, 41 ... support pillar, 51 ... corner part, 52 ... ridge line part

Claims (6)

A radiation detection panel for detecting radiation;
A housing for housing the radiation detection panel;
A film-like anti-scattering material deposited on at least a part of the inner surface of the housing;
A radiation detection apparatus comprising the radiation detection apparatus.   The casing is a rectangular parallelepiped having an incident surface on which radiation is incident and a side surface forming a side surface perpendicular to the incident surface, and the scattering prevention material is attached to the inside of a corner portion where adjacent side surfaces are connected. The radiation detection apparatus according to claim 1, wherein:   The radiation detection apparatus according to claim 1, wherein the scattering prevention material is formed of a sheet-like material.   The radiation detection apparatus according to claim 1, wherein the scattering prevention material is made of a coating material.   The radiation detection apparatus according to claim 1, wherein the scattering prevention material is attached to the entire inner surface of the casing. The radiation detection apparatus according to claim 1, wherein the casing includes a plurality of members, and the scattering prevention material is provided across the plurality of members.

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