Radiation detector structure

Abstract

To provide a radiation detector structure.SOLUTION: A portable radiation cassette 10 is provided. The portable radiation cassette 10 includes a scintillator 20, a photosensitive slab 30, the scintillator 20 and the photosensitive slab 30 forming a panel 40 and the panel 40 including a front surface 410 intended to receive an incident X ray and a rear surface 420 facing the front surface 410, an electronic circuit board 50, and a mechanical protective housing 60 having the panel 40 and the electronic circuit board 50 disposed thereon and including an upper surface 610 and a bottom surface 620. In the portable radiation cassette 10, the upper surface 610 of the mechanical protective housing 60 includes a first layer 611 of a rigid material, a second layer 612 of a rigid material in contact with the front surface 410 of the panel 40, and a layer 613 of a bubble material disposed between the first layer 611 and the second layer 612 of the rigid material.SELECTED DRAWING: Figure 2

Description

[Technical Field]

[0001] The present invention is in the field of imaging. The invention can be applied to any type of imager (especially X-ray, visible and infrared imagers). The invention is described herein by way of example and without loss of applicability to other imaging fields within the field of X-ray medical imaging. The present invention relates to portable radiological cassettes, and in particular to an innovative radiological cassette construction that enhances the protection of the cassette against drops, impacts from external objects, local or distributed pressure, and any stress. [Background technology]

[0002] In the past, radiation systems were bulky and therefore mostly immobile. It was necessary to position the object relative to the system to acquire the desired image. With the advent of solid-state detectors, detectors became less bulky and therefore possible to move the detector relative to the object, which remained fixed. For medical radiation, digital detectors were produced in the form of mobile cassettes that are now likely to be placed in close proximity to the patient whose image is needed when the patient's health condition prevents them from being moved to a room reserved for radiation.

[0003] A digital radiological cassette essentially consists of at least one scintillator, the role of which is to emit visible light under the action of X-rays, a matrix of photodiodes fabricated on a substrate, usually made of glass (hereinafter referred to as a "slab"), which converts the light signals emitted by the scintillator into electrical charges, and one or more electronic circuit boards which read out these charges and convert them into a visible digital image.

[0004] The need for flexibility and responsiveness in the use of this type of equipment has led manufacturers to propose portable digital radiology cassettes. These portable cassettes must then combine extreme resistance to external aggressions with reduced weight and size. Indeed, during their handling and over their lifespan, these portable cassettes can be subjected to drops, impacts from external objects, localized or distributed pressure loads, and bending stresses when the weight of a patient rests on an unevenly supported detector. For this reason, the mechanical structure of the detector must ensure maximum protection of the vulnerable elements: the scintillator, the slab, and the electronic circuit board.

[0005] In traditional portable radiology cassette designs, the scintillator is associated with a slab to form a subassembly called a panel. This panel is held against a base that provides rigidity and mechanical support to the panel. Finally, the panel is outfitted with one or more electronic circuit boards before being inserted into the housing. The thickness of this housing (especially the thickness of the front face of the housing facing the X-ray source) is usually limited to limit the overall weight of the portable cassette and to ensure low absorption of X-rays passing through the portable cassette.

[0006] Figure 1 shows a cross-sectional view of a portable radiation cassette structure known from the prior art. Conventionally, a portable radiation cassette 1 includes: a scintillator 2 capable of converting incident X-rays into a light signal; a photosensitive slab 3 capable of converting the light signal emitted by the scintillator 2 into an electric charge after conversion of the X-rays. The scintillator 2 and the photosensitive slab 3 form a panel 4. The panel 4 comprises a front surface 41 intended to receive incident X-rays according to the X-ray incidence direction Z, a rear surface 42 opposite the front surface 41, and two lateral edges 43 (in a cross-sectional view). - an electronic circuit board 5 that ensures the conversion of the electric charge into a digital image; A mechanical protective housing 6 in which the panel 4 and the electronic circuit board 5 are placed, the mechanical protective housing 6 including a top surface 61 onto which incident X-rays are projected, a bottom surface 62 opposite the top surface 61, and two side surfaces 63 (in a cross-sectional view).

[0007] The portable radiological cassette 1 also includes two fixed supports 7 positioned inside the housing 6, each of which rests against a side surface 63 of the housing. The two fixed supports 7 form a kind of base for the panel 4.

[0008] The panel is held at its lateral edges 43 against the sides 63 of the housing 6 by the use of fixed supports 7. Thus, there is at least one cavity 64 inside the housing 6, defining an open space between the front surface 41 of the panel 4 and the top surface 61 of the housing 6. Optionally, there may also be a second open space between the rear surface 42 of the panel 4 and the bottom 62 of the housing 6, which is partially filled by an electronic circuit board 5.

[0009] Next, flexible foam 8 is inserted into cavity 64 to completely fill cavity 64 and to make physical contact with front surface 41 of panel 4 on one side and top surface 61 of housing 6 on the other side. Since the ISO 4090 standard is restrictive regarding the dimensions of portable cassettes, flexible foam 8 needs to be highly malleable. This flexible foam 8 provides insulation against impact in the direction Z of incidence of X-rays.

[0010] Thus, the base formed by the fixed support 7 provides rigidity and avoids excessive deformation of the panel 4 if the portable cassette is dropped or flexed, while the flexible foam 8 of the housing 6 makes it possible to protect the panel 4 from impacts. Finally, the combined rigidity of the housing 6 (with the flexible foam 8) and the base avoids any significant deterioration in case of pressure on the cassette.

[0011] Nevertheless, thickness constraints on the housing, and in particular compliance with the ISO 4090 standard which limits this dimension to 15 millimeters, prevent each of these parts (i.e., base, housing 6 and flexible foam 8) from being provided with a thickness that would be desirable to fully fulfil their function.

[0012] For this reason, the state-of-the-art portable cassette 1 depicted in Figure 1 has proven to be less robust than desired. Summary of the Invention [Problem to be solved by the invention]

[0013] The present invention aims to alleviate all or some of the above cited problems by proposing an innovative portable radiation cassette structure that enhances its rigidity, ensures higher resistance to deformation and allows for more effective protection of the vulnerable elements contained in the portable radiation cassette. [Means for solving the problem]

[0014] To that end, the subject of the present invention is a portable radiological cassette comprising: - a scintillator capable of converting incident X-rays into a light signal, a photosensitive slab capable of converting light signals emitted by a scintillator into electric charges, the scintillator and the photosensitive slab forming a panel, the panel having a front surface intended to receive incident X-rays and a rear surface opposite to the front surface, - an electronic circuit board that ensures the conversion of electrical charges into a digital image; A mechanical protective enclosure in which the panel and electronic circuit board are placed, the mechanical protective enclosure including a top surface and a bottom surface.

[0015] The portable radiological cassette is characterized in that the top surface of the mechanical protective housing includes: a first layer of rigid material; - a second layer of rigid material in contact with the front face of the panel, a layer of cellular material disposed between the first layer of rigid material and the second layer of rigid material;

[0016] According to one aspect of the invention, the layer of cellular material is made of foam.

[0017] According to one aspect of the invention, the layer of cellular material comprises a stack of at least partially hollow tubes extending generally perpendicular to the front surface of the panel.

[0018] According to one aspect of the invention, the layer of cellular material comprises a plurality of beads Includes:

[0019] According to one aspect of the present invention, beads is hollow.

[0020] According to one aspect of the invention, a second layer of rigid material is adhered to the front surface of the panel.

[0021] According to one aspect of the invention, the layer of cellular material is defined by a third thickness, and the first and second layers of rigid material are defined by first and second thicknesses, respectively, the first and second thicknesses being less than the third thickness of the layer of cellular material.

[0022] According to one aspect of the invention, the layer of cellular material is composed of an organic composite.

[0023] According to one aspect of the invention, the first and / or second layer of rigid material is made of aluminum and / or and / or magnesium and / or carbon or mineral organic fiber composite.

[0024] According to one aspect of the present invention, the portable radiation cassette includes an anti-backscattering protective film disposed against the rear surface of the panel, the anti-backscattering protective film preferably being composed of at least one material of high atomic mass.

[0025] In accordance with one aspect of the present invention, the portable radiation cassette includes a thermal barrier positioned between the electronic circuit board and the rear surface of the panel.

[0026] The invention will be better understood and other advantages will become apparent on reading the detailed description of one embodiment thereof, given by way of example and illustrated by the accompanying drawings, in which: FIG. [Brief explanation of the drawings]

[0027] [Figure 1] 1 shows a schematic cross-sectional view of a portable digital cassette structure known from the prior art; [Figure 2] 1 is a schematic representation of a portable digital cassette structure according to the present invention; [Figure 3] 1 is a schematic representation of an exploded view of the top surface of a housing of a portable digital cassette according to the present invention; [Figure 4] 10 is a schematic representation of an exploded view of the top surface of a housing of a portable digital cassette according to an alternative embodiment of the present invention; DETAILED DESCRIPTION OF THE INVENTION

[0028] For purposes of clarity, like elements will have the same reference numbers in the various drawings.

[0029] 2 is a schematic representation of a portable digital cassette 10 according to the present invention. The portable radiological cassette 10 includes: a scintillator 20 capable of converting incident X-rays into a light signal, a photosensitive slab 30 capable of converting the light signal emitted by the scintillator 20 into an electric charge. The photosensitive slab 30 is, by way of example, a matrix of photosensitive elements. The scintillator 20 and the photosensitive slab 30 form a panel 40 having a front surface 410 intended to receive incident X-rays and a rear surface 420 opposite the front surface 410. an electronic circuit board 50 ensuring the conversion of the electric charges into a digital image; a mechanical protective enclosure 60 in which the panel 40 and the electronic circuit board 50 are placed, the mechanical protective enclosure 60 including a top surface 610 and a bottom surface 620;

[0030] The top surface 610 of the mechanical protective housing 60 includes: - a first layer 611 of rigid material made of aluminum and / or magnesium and / or carbon or mineral-organic fiber composite; a second layer 612 of rigid material. The second layer 612 of rigid material is in direct contact with the front surface 410 of the panel 40. In particular, the scintillator 20 of the panel 40 rests against the second layer 612 of rigid material. The second layer 612 of rigid material therefore ensures the role of a rigid structure and therefore allows the panel 40, which is a fragile element, to be held firmly. Without this contact, a simple twisting of the panel could result in undesirable deterioration of the panel 40. Preferably, the second layer 612, which may be made of a material different from the first layer 611, is obtained from the same rigid material as the first layer 611; A layer of cellular material 613 disposed between the first layer of rigid material 611 and the second layer of rigid material 612. The layer of cellular material 613 may be made of foam.

[0031] This stacking of the first layer 611 of foam material 613 and the second layer 612 of rigid material can be likened to a so-called "sandwich" structure. The layer 613 of foam material is therefore in contact with the first layer 611 of rigid material and the second layer 612 of rigid material so as to completely fill the space within the mechanical protective housing 60 between them. This continuous stacking has the advantage of minimizing the absorption of X-rays while ensuring the overall rigidity of the assembly against shocks as well as torsion. As a variant, the layer 613 of foam material can be fixed to the first layer 611 of rigid material and the second layer 612 of rigid material. By way of example, this fixing can be performed by gluing.

[0032] Thanks to this new structure, the base formed in the portable radiation cassette according to the state of the art can be eliminated, allowing the new portable radiation cassette to achieve a reduced weight.

[0033] Advantageously, the first layer 611 and the second layer 612 of rigid material, like the layer 613 of foam material, weakly absorb X-rays, thereby ensuring good reception of X-rays by the scintillator 20 of the panel 40. Furthermore, the second layer 612 of rigid material can be glued to the front surface 410 of the panel 40 in order to completely fix the panel 40 relative to the second layer 612 and ensure good rigidity of the panel 40. Therefore, any type of permanent adhesive that allows the panel 40 to be glued to the second layer 612 of rigid material can be used, such as a double-sided adhesive, a plastic adhesive that can dry, or any other weak chemical bond (called van der Waals bond), etc.

[0034] Furthermore, the portable radiation cassette 10 according to the present invention may include an anti-backscatter protective film 90 arranged against the rear surface 420 of the panel 40. Ideally, the anti-backscatter protective film 90 is in direct contact with the rear surface 420 of the panel 40. The anti-backscatter protective film 90 is preferentially made of one or at least one high atomic mass material or combination of materials whose atomic number is strategically selected and is intended to limit backscattering of X-rays in the direction of the panel 40 to a direction generally opposite the incident direction Z of the X-rays which could possibly impair the correct operation of the panel 40 and therefore the portable radiation cassette 10. The portable radiation cassette 10 may also include an electromagnetic shielding plate 92 arranged against the anti-backscatter protective film 90 on the other side thereof to insulate the panel 40 from any electromagnetic waves generated by the electronic circuit board 50.

[0035] The portable radiology cassette 10 may include a thermal insulation layer 94 positioned between the electronic circuit board 50 and the rear surface 420 of the panel 40 to insulate the panel from heat generated by the electronic circuit board 50.

[0036] Finally, the portable radiation cassette 10 may include an electronic circuit board 50 energy source (not shown).

[0037] 3 depicts an exploded view of the top surface 610 of the housing 60 of the portable digital cassette 10. As previously mentioned, the top surface 610 of the housing 60 of the portable digital cassette 10 is defined by a continuous stack of a first layer 611, a layer 613 of foam material, and a second layer 612 of rigid material.

[0038] Thus, the first layer 611 is defined by a first thickness e1, the second layer 612 of rigid material is defined by a second thickness e2, and the layer 613 of cellular material is defined by a third thickness e3. According to one embodiment of the present invention, the first thickness e1 and the second thickness e2 are identical. Thus, and by way of example, the first thickness e1 and the second thickness e2 may have a minimum thickness of approximately 0.2 millimeters to a maximum thickness of 0.7 millimeters. Nevertheless, asymmetric structures may also be envisioned. Thus, the first thickness e1 of the first layer 611 may be different from the second thickness e2 of the second layer 612. By way of example, the first thickness e1 may be 0.3 millimeters to 1.5 millimeters, and the second thickness e2 may be 0.3 millimeters to 1 millimeter. Preferably, in the case of an asymmetric structure between the first thickness e1 and the second thickness e2, the first thickness e1 is greater than the second thickness e2. In fact, with regard to the first layer 611, which can be compared to the outer casing of the housing 60, increasing its thickness (i.e., increasing the thickness e1) makes it possible to increase the thickness of the outer casing of the housing 60 and thus to increase the resistance of the housing 60 to impacts and deformations originating from the external environment.

[0039] The third thickness e3 of the layer 613 of cellular material is much greater than the first thickness e1 and the second thickness e2. More specifically, the third thickness e3 may be, for example, between 2 and 4 millimeters. It is therefore possible to establish a size ratio between the third thickness e3 and the sum of the first thickness e1 and the second thickness e2, which may vary between 2 and 8 depending on the sizes of the first, second and third thicknesses e1, e2 and e3.

[0040] Therefore, in addition to the fact that the layer of foam material 613 is generally non-absorbent to X-rays, this small dimensioning of the first thickness e1 and second thickness e2, which are much smaller than the third thickness of the layer of foam material, does not degrade the quality of the image produced.

[0041] In practice, the layer of cellular material 613 is made of an organic compound that absorbs little or no X-rays. More specifically, the layer of cellular material 613 is made of a number of organic compounds in the first embodiment. beads 6130. These semi-rigid beads 6130 completely fills the third thickness e3. Furthermore, it has a circular or elliptical shape. beads 6130 and a layer of cellular material 613 having a parallelepiped shape, beads The empty spaces 6140 between the layers 6130 appear uniform. Thus, in the event of an impact or load inducing deformation of the cellular material layer 613, beads 6130 are compressed together, thus reducing the free space 6140. beads Since 6130 is semi-rigid, beads 6130 can also be deformed in the event of extreme impact or load applied to the layer of cellular material 613 .

[0042] In this way, the layer of cellular material 613 remains a rigid layer to assume the deformation associated with an impact or load rather than the panel 40, and is not a malleable foam that retains the ability to be fully deformable.

[0043] In addition, it is transformed beads To increase the capacity of the 6130 beads 6130 is hollow beads It could be.

[0044] Nevertheless, in the second embodiment, the layer 613 of cellular material is formed by a stack of at least partially hollow tubes 6150 extending at approximately right angles to the front face 411 of the panel 40, as depicted in FIG. beads6130. Like the internal bamboo structure, the tubes 6150 are compartmentalized by nodes such that they can be considered as a set of tubes separated by partitions. Tubes 6150 stacked in this manner within the layer 613 of cellular material are in direct contact with each other.

[0045] The tubes 6150 may be of oval, square, or rectangular cross-section, but preferentially have a hexagonal cross-section. The tubes extend approximately parallel to the direction of incidence Z of the X-rays at the third thickness e3 of the layer of cellular material 613. Therefore, there are also empty spaces 6140 between the tubes 6150, which allow the layer of cellular material 613 to be easily deformed. Furthermore, the tubes 6150 may also be deformable, further increasing the ability of the layer of cellular material 613 to be deformed in the event of an impact or load that induces deformation of the layer of cellular material 613.

[0046] Furthermore, in another preferred embodiment, it is possible to envision using a cellular layer 613 that includes a series of deformable materials, such as cellular materials, and rigid cellular bodies defined as macroscopically uniform cavities, the cellular bodies having a matrix macroscopic shape, such as a honeycomb shape, that exhibits macroscopic uniformity. Otherwise, the non-uniform presence of void spaces within the cellular layer 613 may induce shadows on the generated image, thus degrading the quality of the generated image.

[0047] It is further possible to envisage using enlarged structures within the layer 613 of cellular material to increase its ability to be deformed.

[0048] Thus, the top surface 610 of the housing 60 of the portable digital cassette 10 (defined by the successive stacking of the first layer 611, the layer 613 of foam material, and the second layer 612 of rigid material) presents a stiffness that is 3 to 10 times greater than the stiffness of the housing 6, in addition to the stiffness of the base formed inside the state-of-the-art housing 6 depicted in FIG. 1. Furthermore, deformation of the top surface 610 of the housing 60 when dropped or bent is reduced by the same proportion. The panel 40, which is adhered to this top surface 610 via the second layer 612, is nearly non-deformable and no longer undergoes deformations that could damage the housing 60. Furthermore, this "sandwich" construction of the successive stack of first layer 611, layer of foam material 613, and second layer of rigid material 612 makes it possible to limit the thickness of top surface 610 to a thickness that is equivalent to that commonly used in the construction of portable radiological cassettes 1, thus complying with the ISO 4090 standard and not degrading the quality of the images produced, the layer of foam material 613 exhibiting negligible X-ray absorption. [Explanation of symbols]

[0049] 1 portable radiation cassette 2. Scintillator 3 Photosensitive slabs 4 Panels 5. Electronic circuit boards 6. Housing 7 Fixed support 8. Flexible Foam 10 Portable Radiation Cassette 20 Scintillator 30 Photosensitive slabs 40 panels 41 Front 42 Rear 43 Horizontal edge 50 Electronic Circuit Boards 60 Mechanical protective enclosure 61 Top surface 62 bottom 63 Side 64 Cavity 90 Anti-backscatter protective film 92 Electromagnetic Shielding Plate 94 Insulation Layer 410 Front 420 Rear 610 Top 611 First Layer 612 Second Layer 613 Layer of cellular material 620 bottom 6130 Many beads 6140 Empty Space 6150 tube e1, e2, e3 thickness

Claims

1. a scintillator (20) capable of converting incident X-rays into a light signal, a photosensitive slab (30) capable of converting the light signal emitted by the scintillator (20) into an electric charge, the scintillator (20) and the photosensitive slab (30) forming a panel (40), the panel (40) having a front surface (410) intended to receive the incident X-rays and a rear surface (420) opposite the front surface (410); an electronic circuit board (50) ensuring the conversion of said charges into a digital image; a portable radiation cassette (10) comprising a mechanical protective housing (60) in which the panel (40) and the electronic circuit board (50) are arranged and which comprises a top surface (610) and a bottom surface (620), the portable radiation cassette (10) being characterized in that the top surface (610) of the mechanical protective housing (60) - a first layer of rigid material (611), a second layer (612) of rigid material in contact with said front surface (410) of said panel (40); - a layer of foam material (613) disposed between said first layer of rigid material (611) and said second layer of rigid material (612) and in contact with said first layer of rigid material (611) and said second layer of rigid material (612).

2. 10. The portable radiological cassette (10) of claim 1, wherein said layer of foam material (613) is made of foam.

3. 2. The portable radiological cassette (10) of claim 1, wherein the layer (613) of foam material comprises a stack of at least partially hollow tubes (6150) extending substantially perpendicular to the front surface (410) of the panel (40).

4. 10. The portable radiological cassette (10) of claim 1, wherein the layer of foam material (613) comprises a number of beads (6130).

5. 5. The portable radiological cassette (10) of claim 4, wherein said beads (6130) are hollow.

6. A portable radiological cassette (10) according to any one of the preceding claims, wherein the second layer (612) of rigid material is adhered to the front surface (410) of the panel (40).

7. 7. A portable radiological cassette according to claim 1, wherein the layer of foam material (613) is defined by a third thickness (e3), and the first layer of rigid material (611) and the second layer of rigid material (612) are defined by first and second thicknesses (e1, e2), respectively, and the first and second thicknesses (e1, e2) are less than the third thickness (e3) of the layer of foam material (613).

8. A portable radiological cassette (10) according to any one of the preceding claims, wherein said layer of foam material (613) is made of an organic compound.

9. 9. A portable radiological cassette (10) according to any one of claims 1 to 8, wherein the first layer of rigid material (611) and / or the second layer of rigid material (612) are made of aluminium and / or magnesium and / or carbon or mineral organic fibre composite.

10. 10. The portable radiation cassette (10) according to any one of claims 1 to 9, comprising an anti-backscattering protective film (90) arranged against the rear face (420) of the panel (40) and preferably made of at least one material of high atomic mass.

11. 11. A portable radiological cassette according to any one of claims 1 to 10, comprising a thermal insulation layer (94) positioned between the electronic circuit board (50) and the rear face (420) of the panel (40).

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