JP2008170374A - Radiation detection apparatus and scintillator panel - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a radiation detection apparatus or a scintillator panel that does not have irregularities in the characteristics, enhancing the resolution without causing deteriorating of the emission amount. <P>SOLUTION: The radiation detection apparatus has a photoelectric conversion panel 100; a scintillator layer 200 arranged on the photoelectric conversion panel 100; and a protection layer 301 that covers the scintillator layer 200. The scintillator layer 200 is constituted of a dendrite and has a blocking member 401 that blocks the gap among the dendrites. In addition, the blocking member 401 are particles, and the diameter of the blocking member 401 is larger than the gap. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a radiation detection apparatus and a scintillator panel, and more particularly to a radiation detection apparatus and a scintillator panel having a scintillator layer composed of columnar crystals.

  In recent years, digitization of X-ray photography has been accelerated, and various radiation detection apparatuses have been announced.

  There are two methods: a direct method, that is, a type that directly converts X-rays into electric signals and reads, and an indirect method, that is, a type that converts X-rays into visible light and then converts visible light into electric signals and reads them. It is roughly divided into two.

  Patent Document 1 discloses a technique in which a color treatment is applied to a polyparaxylylene film in an indirect radiation detection apparatus in which a columnar crystal scintillator is covered with a polyparaxylylene film.

  According to this technology, the fluorescence transmitted through the interface of the columnar structure is absorbed by the polyparaxylylene film subjected to the color development treatment, and the resolution of the scintillator panel can be improved due to the phenomenon of the fluorescence crosstalk component. It is said.

  Further, even if a columnar crystal scintillator layer is formed directly on the image sensor, the same effect is obtained if similar processing is performed.

  Patent Document 2 includes an X-ray conversion unit that is provided in a photoelectric conversion element and includes a scintillator layer that has a columnar structure and converts incident X-rays into visible light, and a protective film provided on the surface of the scintillator layer. An X-ray detector is disclosed. This document describes a technique in which the light reflecting material particles that reflect the converted visible light are dispersed and contained in the protective film.

  Patent Document 3 discloses a radiation having a phosphor layer made of CsI: Tl, a protective layer formed on the phosphor layer, a reflective layer made of an aluminum thin film, and a protective layer further formed on the reflective layer. A detection device is disclosed.

  Patent Document 4 discloses a first portion that is optically discontinuous in the surface direction by being grown in a columnar shape at a predetermined height, and a first portion that is continuously covered in the surface direction with the material of the scintillator itself. A scintillator layer in which two portions are integrally formed is disclosed. This document discloses a scintillator layer in which a moisture absorption preventing film is provided on the entire surface of the second portion and at least the outermost portion of the first portion to be airtight.

Patent Document 5 is composed of a scintillator layer as means for converting X-rays into visible light and an image sensor that converts visible light into video signals. The scintillator layer is a columnar crystal, and a reflective layer is provided on the scintillator layer. An X-ray imaging apparatus is disclosed.
JP 2000-9846 A JP 2005-28383 A JP 2005-148060 A JP 2003-75593 A JP 09-206296 A

  However, when the above scintillator panel is used, the following problems occur.

  In the technique described in Patent Document 1, the resolution is improved, but the color-treated polyparaxylylene film absorbs even a level of fluorescence that does not cause a problem in resolution, so the amount of emitted light is extremely reduced. End up.

  The state of the columnar crystals is not actually uniform, and there are some narrow portions and some wide portions. In the technique described in Patent Document 1, it is difficult to enter the polyparaxylylene film particularly in a narrow portion, and unevenness in resolution and luminance occurs.

  Accordingly, an object of the present invention is to provide a radiation detection device or a scintillator panel that improves resolution and does not have unevenness in characteristics without reducing the amount of light emitted.

  The present invention provides a radiation detection apparatus having a photoelectric conversion panel, a scintillator layer disposed on the photoelectric conversion panel, and a protective layer covering the scintillator layer, as means for solving the above-described problems. The layer is composed of columnar crystals, and has a blocking member that closes gaps between the columnar crystals.

  Further, the present invention provides a scintillator panel having a support member, a scintillator layer disposed on the support member, and a protective layer covering the scintillator layer, wherein the scintillator layer is composed of columnar crystals, and the columnar It has the obstruction | occlusion member which plugs up the clearance gap between crystals.

  According to the present invention, it is possible to realize a radiation detection device or a scintillator panel that improves resolution and has no unevenness in characteristics without reducing the amount of emitted light.

  DESCRIPTION OF THE PREFERRED EMBODIMENTS The best mode for carrying out the present invention will be described below with reference to the accompanying drawings.

  In the present invention, a blocking member is disposed in a gap above the column so that a substance other than a gas does not enter the gap between columns of the scintillator layer formed in the columnar crystal.

  As a result, when forming the protective layer, it is possible to prevent the material of the protective layer from being mixed into the gaps between the columns, and the difference in refractive index between the columns and the gaps does not decrease. The function is not degraded.

  The shape of the closing member is not particularly limited, but particles are preferable in consideration of the production method.

  The occluding member may be a hollow particle.

  The size of the blocking member needs to be such that it does not enter the gap at the top of the column. Since the gaps at the top of the pillars vary, it is preferable that the variation is 3σ or more.

  It is preferable that the refractive index of the blocking member is substantially the same as the refractive index of the protective layer in contact with both the scintillator layer and the blocking member.

  The occlusion member may be substantially transparent to fluorescence even if it has an absorption characteristic for an arbitrary wavelength. In other words, it is not necessarily a substance that transmits 100% of fluorescence.

  The material of the closing member may be organic or inorganic.

  The material of the closing member is selected from the following materials in the case of an organic substance.

  Examples thereof include polystyrene, crosslinked polystyrene, crosslinked polymethyl methacrylate, crosslinked polybutyl methacrylate, crosslinked styrene-acrylate, styrene-acrylate, divinylbenzene, styrene-butadiene, and polyvinyltoluene.

  In the case of an inorganic substance, the material of the closing member is selected from titanium oxide, tantalum oxide, aluminum oxide, silicon oxide, silicon carbide, silicon nitride, zinc oxide and the like.

  The material of the closing member may be selected from oxides of alkaline earth metals such as MgO, CaO, SrO, BaO.

  If a blocking member made of a material selected from alkaline earth metal oxides is used, this also functions as a moisture getter agent, so that moisture resistance can be improved.

  In the case where the closing member is a particle, it is better to apply a thermoplastic adhesive around it to improve the adhesion.

  The columnar crystal scintillator layer is selected from alkali halide phosphors represented by CsI: TI, CsI: Na, NaI: TI, LiI: Eu, KI: TI, and the like.

  As the protective layer in contact with the closing member and the scintillator layer, an acrylic, urethane, or silicone type adhesive that is coated with a liquid material and cured by a method such as heating or UV irradiation can be used.

  When these materials are applied to the upper surface of the scintillator layer, the closing member can prevent the flow intrusion into the gap.

  For the protective layer in contact with the closing member and the scintillator layer, an adhesive material made of tack at normal temperature can be used. When pasted with an adhesive material, the blocking member can prevent the adhesive material from biting into the gap.

  A thermoplastic hot melt material can be used for the protective layer in contact with the closing member and the scintillator layer. When the hot melt is melted and pressed against the scintillator layer, it is possible to prevent the hot melt having high fluidity from flowing into the gap.

  An organic or inorganic material formed by a dry process such as CVD or PVD can be used for the protective layer in contact with the closing member and the scintillator layer.

  As the organic material, materials such as polyparaxylylene, polyimide, and polyurea are preferable. As the inorganic material, silicon oxide, silicon nitride, silicon carbide, zinc oxide, aluminum oxide, or the like is preferably used. When depositing these materials, the blocking member can prevent floating intrusion from the material space.

  As a method of applying the particulate occlusion member to the surface of the scintillator layer, it is preferable to disperse the particles. Give vibration to the whole to some extent in the gap. The whole should be blown with air blow to remove excess particles. However, other methods may be used.

  In order to bring the particulate occlusion member and the scintillator layer into close contact with each other, it is particularly preferable that the particles made of an organic material be applied and then heated to nearly 200 ° C. to be melted. It is even better if a thermoplastic adhesive is applied around the particles.

  In order to bring the particulate occlusion member and the scintillator layer into close contact with each other, the particles may be mixed in the protective layer in advance and pressed and bonded as they are.

  By doing so, when the protective layer tries to enter the gap, the same effect can be expected because the particles stand in the gap with a certain probability. By doing so, there is no limitation that the material of the particles is melted, so inorganic materials can also be applied.

  Moreover, it is preferable that the upper end of the columnar part of the scintillator layer has a weight shape. This is because when the closing member is a particle, the particle is likely to be sandwiched between the upper ends of adjacent columnar crystals and is more easily closed.

[Embodiment 1]
FIG. 1 is a cross-sectional view showing a radiation detection apparatus as a first embodiment of the present invention.

  This is an example applied to a radiation detection apparatus in which a columnar crystal scintillator layer 200 is directly deposited on the photoelectric conversion panel 100.

  A plurality of photoelectric conversion elements 102 and a plurality of TFT elements 103 are formed on a glass substrate 101 and the whole is covered with a protective layer 104.

  A columnar crystal scintillator layer made of CsI: TI is formed on the upper surface of the protective layer 104, and a protective layer 301 made of hot melt, a reflective layer 302 made of Al, and a protective layer 303 made of PET are laminated. 301 to 303 are referred to as a protective sheet 300.

  The cross-linked polystyrene particles 401 are arranged at the upper part of the pillar, which prevents the hot melt from entering the gaps during melting.

  2 and 3 are enlarged views of part A of FIG. In FIG. 2, a single layer of particles covers the gap neatly. However, even if a plurality of layers cover the gap as shown in FIG. 3, there is no problem because there is substantially no difference in refractive index and no light scattering occurs.

  FIG. 4-6 is an enlarged cross-sectional view showing a process of forming the radiation detection apparatus as the first embodiment of the present invention. First, a columnar scintillator layer is formed on a substrate as shown in FIG.

  Next, as shown in FIG. 5, the particles are scattered on the scintillator layer and subjected to vibration, and excess particles are blown off by air blowing. Then, by further curing this at 200 ° C., the particles are slightly melted to bring the particles into close contact with the scintillator layer.

  Next, the protective sheet 300 is thermocompression bonded from above to obtain a structure shown in FIG.

  As a result, the hot melt material is prevented from entering the gaps between the pillars, and the hot melt 301 does not bite into the upper portion as shown in FIG.

[Embodiment 2]
8 and 9 are enlarged cross-sectional views showing a radiation detection apparatus as a second embodiment of the present invention.

  A description of the same parts as those in the first embodiment is omitted. This is an example in which a thermoplastic resin 403 is applied around the particles of the closing member 402.

  This makes it possible to increase the choice of temperature at the time of bringing the particles into close contact. Furthermore, when the protective sheet is thermocompression-bonded, a process can be adopted in which particles are also brought into close contact with the scintillator layer.

[Embodiment 3]
FIG. 10 is an enlarged cross-sectional view showing a radiation detection apparatus as a third embodiment of the present invention.

  A description of the same parts as those in the first embodiment is omitted. In this example, the particles of the blocking member are mixed in the hot melt of the protective sheet 300 in advance.

  FIG. 11 is an enlarged sectional view showing this forming method.

  Since the particles are mixed in the protective sheet 300 in advance, there is no step of applying the particles to the scintillator layer.

  Further, an inorganic material that does not melt by heat can be applied as particles.

[Embodiment 4]
FIG. 12 is a cross-sectional view showing a radiation detection apparatus as a fourth embodiment of the present invention.

  A description of the same parts as those in the first embodiment is omitted. This embodiment is an example in which the protective layer is a polyparaxylylene layer 304 formed by CVD as compared with the first embodiment. A reflective layer 305 and a polyparaxylylene layer 306 made of Al are formed on the top.

  As described above, even if the protective layer 304 in contact with the closing member and the scintillator layer is formed by a dry process, it is possible to prevent the protective layer 304 from entering the gap. 13 and 14 are enlarged views of part B. FIG.

[Embodiment 5]
FIG. 15: is sectional drawing which shows the radiation detection apparatus as the 5th Embodiment of this invention. 16 and 17 are enlarged views of a portion C in FIG.

  A description of the same parts as those in the first embodiment is omitted.

  110 is an FOP, 405 is a particle of a closing member made of styrene, 307 is a colored polyparaxylylene, 308 is a polyparaxylylene, and 309 is an Al thin film.

[Embodiment 6]
FIG. 18 is a sectional view showing a scintillator panel as a sixth embodiment of the present invention. An Al thin film 106 and a protective layer 104 are formed as a reflective layer on a support substrate 105 such as a carbon plate.

  Then, the scintillator layer 200, the blocking member 401, and the protective layer 301 are formed on the protective layer 104 in the same manner as in the first embodiment or the third embodiment.

  When the scintillator panel thus obtained and the sensor panel 100 shown in FIG. 1 are bonded together using an adhesive, a radiation detection apparatus is obtained.

[Embodiment 7]
FIG. 19 is a diagram showing an example in which the radiation detection apparatus according to the present invention is applied as a radiation detection system. The radiation detection apparatus is the radiation detection apparatus of each of the above embodiments.

  As shown in FIG. 19, X-rays 6060 generated by an X-ray tube 6050 serving as a radiation source pass through a chest 6062 of a patient or subject 6061 and enter a radiation detection device 6040 that captures a radiation image. This incident X-ray includes information on the inside of the patient 6061.

  The scintillator of the radiation detector 6040 emits light in response to the incidence of X-rays, and this is photoelectrically converted to obtain electrical information.

  This information is digitally converted and image-processed by an image processor 6070 serving as a signal processing means, and can be observed on a display 6080 serving as a display means in a control room.

  Further, this information can be transferred to a remote place by transmission processing means such as a telephone line 6090, and can be displayed on a display 6081 serving as a display means installed in a doctor room or the like in another place or stored in a recording means such as an optical disk. it can.

  This allows a remote doctor to make a diagnosis.

  Moreover, it can also record on the film 6110 used as a recording medium by the film processor 6100 used as a recording means.

  The present invention can be applied to a scintillator panel using a columnar crystal scintillator layer, and can also be applied to a radiation detection apparatus using a columnar crystal scintillator.

  Moreover, although it can be applied to medical X-ray diagnostic apparatuses such as DR and CT, it is also effective when applied to uses such as nondestructive inspection.

It is sectional drawing which shows the radiation detection apparatus as the 1st Embodiment of this invention. It is the A section enlarged view of FIG. It is the A section enlarged view of FIG. It is the expanded sectional view which showed the process of formation of the radiation detection apparatus as the 1st Embodiment of this invention. It is the expanded sectional view which showed the process of formation of the radiation detection apparatus as the 1st Embodiment of this invention. It is the expanded sectional view which showed the process of formation of the radiation detection apparatus as the 1st Embodiment of this invention. It is the expanded sectional view which showed the process of formation of the radiation detection apparatus as the 1st Embodiment of this invention. It is an expanded sectional view which shows the radiation detection apparatus as the 2nd Embodiment of this invention. It is an expanded sectional view which shows the radiation detection apparatus as the 2nd Embodiment of this invention. It is an expanded sectional view which shows the radiation detection apparatus as the 3rd Embodiment of this invention. It is the expanded sectional view which showed the process of formation of the radiation detection apparatus as the 3rd Embodiment of this invention. It is sectional drawing which shows the radiation detection apparatus as the 4th Embodiment of this invention. It is the B section enlarged view of FIG. It is the B section enlarged view of FIG. It is sectional drawing which shows the radiation detection apparatus as the 5th Embodiment of this invention. It is the C section enlarged view of FIG. It is the C section enlarged view of FIG. It is sectional drawing which shows the scintillator panel as the 6th Embodiment of this invention. It is a figure which shows the radiation detection system as the 7th Embodiment of this invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 100 Photoelectric conversion panel 101 Glass substrate 102 Photoelectric conversion element 103 TFT element 104 Protective layer 110 Fiber optical plate 200 Columnar crystal scintillator layer 300 Protective sheet 301 Hot melt 302 Al
303 PET
304 Polyparaxylylene 305 Al Thin Film 306 Polyparaxylylene 307 Colored Polyparaxylylene 401 Occlusion Member Particles 402 Occlusion Member Particles 403 Thermoplastic Resin 404 Occlusion Member Particles 405 Occlusion Member Particles

Claims (12)

In a radiation detection apparatus having a photoelectric conversion panel, a scintillator layer disposed on the photoelectric conversion panel, and a protective layer covering the scintillator layer,
The scintillator layer is composed of columnar crystals,
A radiation detection apparatus comprising a closing member that closes a gap between the columnar crystals. The radiation detecting apparatus according to claim 1, wherein the closing member is a particle. The radiation detection apparatus according to claim 2, wherein a diameter of the blocking member is larger than the gap. 4. The radiation detection apparatus according to claim 1, wherein an upper end of a columnar portion of the scintillator layer of the columnar crystal has a weight shape. 5. The radiation detection apparatus according to claim 1, wherein a refractive index of the blocking member is substantially the same as a refractive index of the protective layer. The radiation detection apparatus according to claim 1, wherein a thermoplastic resin is applied to a surface of the closing member. In a scintillator panel having a support member, a scintillator layer provided on the support member, and a protective layer covering the scintillator layer,
The scintillator layer is composed of columnar crystals,
A scintillator panel comprising a closing member that closes a gap between the columnar crystals. The scintillator panel according to claim 7, wherein the closing member is a particle. The scintillator panel according to claim 8, wherein a diameter of the closing member is larger than the gap. The scintillator panel according to any one of claims 7 to 9, wherein an upper end of a columnar portion of the scintillator layer of the columnar crystal has a weight shape. 11. The scintillator panel according to claim 7, wherein a refractive index of the blocking member is substantially the same as a refractive index of the protective layer. The scintillator panel according to any one of claims 7 to 11, wherein a thermoplastic resin is applied to a surface of the closing member.