Aperiodic scattering mask for reducing X-ray scattering

Abstract

The invention relates to a scattering radiation mask, an arrangement for X-ray imaging, a method for manufacturing a scattering radiation mask and a method for identifying a scattering radiation mask. The scattering radiation mask according to the invention for reducing X-ray scattering radiation, in particular for X-ray imaging, has - an absorption structure produced by an additive manufacturing process, which exhibits an aperiodic pattern in a central section that is not a boundary region, - wherein the absorption structure comprises X-ray-absorbing mask walls, - wherein several mask walls each form a cell-like structure with a laterally enclosed, X-ray-transparent beam channel, characterized in that that in the central section every cell-like structure has the same shape and the same area.

Description

[0001] The invention relates to a scattering radiation mask, an arrangement for X-ray imaging, a method for manufacturing a scattering radiation mask and a method for identifying a scattering radiation mask.

[0002] The requirements for anti-scatter masks, especially for medical X-ray imaging systems, are high. On the one hand, the scattered X-ray photons should be absorbed as completely as possible, while on the other hand, the primary X-ray radiation should reach the X-ray detector as unimpeded as possible. Another important requirement is that the anti-scatter mask should ideally be invisible in the resulting X-ray image, even though the mask material, particularly the X-ray-absorbing layers, covers areas of the X-ray detector, preventing these covered areas from being directly reached by X-ray photons from the X-ray source. For this reason, the amount of material used in the X-ray-absorbing layers should be reduced to an absolute minimum.Ideally, a radiation mask consists of thin metal strips as X-ray-absorbing layers, which are themselves just thick enough to absorb the scattered radiation. Typically, fine lead strips, for example 20 µm thick, are used. Strip widths of approximately 3 mm at intervals of approximately 100 µm have proven effective in practice for producing very high-quality X-ray images.

[0003] Lead strips with cross-sections of 0.020 mm x 3 mm and typical lengths of 400 mm are, however, mechanically unstable. For this reason, a filler material is inserted between these X-ray-absorbing layers. This filler material is undesirable for the X-ray imaging process because it typically absorbs X-rays, at least to a small extent, and is therefore not completely X-ray transparent. Ultimately, any absorption of X-ray photons from the body necessitates an increase in the potentially harmful radiation dose used for the examination. An important development goal for medical X-ray equipment is therefore to minimize the amount of material between the patient and the X-ray detector. Lightweight metals, such as aluminum, or paper are used as fillers between the X-ray-absorbing layers in the medical technology market.

[0004] Current systems for reducing scattered radiation therefore have several technical limitations.

[0005] DE 103 05 106 A1 discloses a scattering beam grid or collimator for the absorption of secondary radiation scattered by an object, which has an absorption structure consisting of a plurality of wall- or rib-like elements, wherein several elements each form a cell-like structure with a laterally enclosed beam channel for primary radiation, wherein the elements and thus the cell-like structures are arranged or shaped in such a way that the absorption structure has a random, aperiodic pattern.

[0006] US4133152 describes a tile set for covering an area, consisting of two types of tiles. Each type is basically four- or five-sided, and the respective shapes are such that when a large number of tiles are arranged next to each other in a suitable configuration, which may be specified by appropriate markings or shapes, the pattern they form will necessarily not be repeated, providing considerable aesthetic appeal.

[0007] The article at https: / / www.spektrum.de / news / parkettierung-mathematiker-feiern-hatfest-fuer-einstein-ka-chel / 2168346 reveals that the hat tile is a special geometric shape that can completely cover a plane while producing only an aperiodic pattern. The hat tile was discovered by David Smith, a retired printing press technician. It has interesting connections to various mathematical fields and demonstrates the existence of aperiodic tiles that do not allow for periodic arrangements, but only a periodic ones. The geometry of the hat tile is an example of a so-called "single tile." Unlike Penrose tiling, which requires two different tile shapes to completely cover a plane, the single tile uses only a single geometric pattern to completely cover a plane with an aperiodic pattern.

[0008] The invention is based on the objective of providing a scattering mask, an arrangement for X-ray imaging, a method for manufacturing a scattering mask and a method for identifying a scattering mask, which are improved, in particular easier to manufacture and / or absorb more scattered X-rays and / or less primary X-rays.

[0009] The problem is solved by the features of the independent claims. Advantageous embodiments are described in the dependent claims.

[0010] The scattering radiation mask according to the invention for reducing X-ray scattering radiation, in particular for X-ray imaging, has - an absorption structure produced by an additive manufacturing process, which exhibits an aperiodic pattern in a central section that is not a boundary region, - wherein the absorption structure comprises X-ray-absorbing mask walls, - wherein several mask walls each form a cell-like structure with a laterally enclosed, X-ray-transparent beam channel, characterized by, that in the central section every cell-like structure has the same shape and the same area.

[0011] Advantageously, in conjunction with additive manufacturing, the invention allows the previous limitations to grid-shaped or strip-shaped scattering masks to be overcome. Improved scattering masks can preferably be designed according to medical applications. This will, in particular, allow for significantly higher quality medical images at a lower radiation dose, since the X-ray scattering is preferably reduced and / or the primary X-ray radiation at the X-ray detector is increased.

[0012] An anti-scatter mask, also commonly referred to as an anti-scatter grid or grid, is used to reduce unwanted scatter radiation during X-ray imaging. X-ray scatter radiation is produced when X-rays interact with matter and are scattered in different directions. This scattered radiation can significantly impair image quality in X-ray diagnostics by reducing contrast and blurring details.

[0013] The anti-scattering mask reduces the incident X-ray scattering radiation, particularly by allowing the X-ray scattering radiation that does not strike the mask perpendicularly to interact with the absorption structure, thereby at least attenuating, and preferably absorbing as completely as possible. In other words, the number of X-ray photons of the X-ray scattering radiation behind the anti-scattering mask is significantly reduced, and preferably maximally minimized, compared to the number of X-ray photons of the X-ray scattering radiation in front of the anti-scattering mask.

[0014] In contrast, the primary X-rays, i.e., X-rays that are not scattered in matter but at most attenuated, ideally pass through the absorption structure, particularly without any absorbing interaction with it. In other words, the number of X-ray photons of the primary X-rays behind the scattering mask is advantageously only slightly lower, and preferably essentially the same, as the number of X-ray photons of the scattered X-rays in front of the scattering mask.

[0015] Whether an X-ray photon is absorbed as scattered X-rays by the scattering mask or transmitted as primary X-rays depends in particular on the angle of incidence of the trajectory on which the X-ray photon is located relative to the surface of the scattering mask. The surface of the scattering mask is, in particular, the top surface of the scattering mask.

[0016] The absorption structure forms the basic structure of the scattering mask. The absorption structure refers to an arrangement comprising at least several mask walls and optionally a filling material with different properties regarding X-rays, particularly regarding its X-ray attenuation. The X-ray attenuation defines the absorption rate of X-rays. The optional filling material exhibits, in particular, a comparatively low X-ray attenuation and thus a high X-ray transmission. The filling material is, in particular, an X-ray-transparent material.

[0017] An aperiodic pattern refers to an arrangement of cell-like structures that do not repeat at regular intervals. In the context of the scattering mask, this means that the cell-like structures in the central section are arranged in such a way that they form an aperiodic, rather than a repeating, pattern. In other words, all cell-like structures, or rather their mask walls, in the central section are arranged such that the absorption structure exhibits the aperiodic pattern.

[0018] A cell-like structure can be understood as a unit enclosed by mask walls. The laterally enclosed, X-ray-transparent beam channel within such a cell-like structure allows primary X-rays to pass through, while scattered X-rays are absorbed by the surrounding mask walls.

[0019] The absorption structure is designed to exhibit an aperiodic pattern. This aperiodic pattern is formed primarily by the multiple mask walls. The central section refers specifically to the length and width of the top surface of the scattering mask. This central section typically extends to the edge of the absorption structure or the scattering mask. The ratio of the central section to the edge is usually many times greater than one, but can deviate from this, particularly if the scattering masks are correspondingly small and / or the cell-like structures are correspondingly large, and may be less than one.

[0020] The multiple mask walls exhibit, in particular, a comparatively high X-ray attenuation property and thus a low X-ray transmission property.

[0021] The radiation channels of the cell-like structures preferably allow for a high transmission of the primary X-ray radiation.

[0022] A mask wall refers to a thin, extended surface of an X-ray-absorbing material. In this context, a mask wall can be understood as a single, continuous surface of the X-ray-absorbing material that is applied, for example, in a single manufacturing step.

[0023] The thickness of a mask wall can range from a few micrometers to several hundred micrometers. For example, the thickness of an X-ray-absorbing mask wall can range from 20 to 200 µm. Mask wall thickness describes the strength of the mask wall. The thickness of such a mask wall can vary depending on the material used and / or desired properties, both between and within the mask wall.

[0024] Preferably, a mask wall is flat. However, it is also conceivable that a mask wall could be curved.

[0025] Each cell-like structure is formed by at least three, typically planar, mask walls. The number of mask walls typically corresponds to the number of vertices of the cell-like structure. The number of mask walls for each cell-like structure in the central section is typically the same.

[0026] The mask walls of a cell-like structure can have the same, partially different, or completely different widths. The mask walls of a cell-like structure can have the same, partially different, or completely different thicknesses. The height of the mask walls of a cell-like structure is typically the same, but can alternatively be variable.

[0027] In the present application, the shape and area of ​​a cell-like structure refer to a cross-section through the radiation channel of the cell-like structure. The cross-section is, in particular, aligned parallel to the top surface of the scattering mask. The shape and area of ​​each cell-like structure are compared, in particular, with the same distance from the top surface of the scattering mask. Specifically, each cell-like structure has a congruent cross-section at the same height of the scattering mask.

[0028] The fact that every cell-like structure in the central section has the same shape and area means, in particular, that every cell-like structure in the central section is identically formed. Each cell-like structure is interchangeable and / or congruent with any other cell-like structure in the aperiodic pattern. The prerequisites for this are, in particular, the same shape and area. In other words, each cell-like structure is, in particular, a single tile, in accordance with the prior art.

[0029] The identical shape is, in particular, a uniform shape. This means, specifically, that the interior angles within each cell-like structure between the adjacent mask walls are the same. Only when the shape is identical can an aspect ratio differ, independent of the area. The fact that the shape and area of ​​each cell-like structure are identical in the central section means, in particular, that each cell-like structure has the same dimensions and / or that each set of multiple mask walls has the same dimensions.

[0030] Typically, each cell-like structure is open in the direction of X-ray transmission, e.g., at the top and bottom, to form a substantially straight beam channel. The multiple mask walls are, in particular, the side walls of the cell-like structure, which preferably completely encloses the beam channel, especially by 360°. Preferably, each cell-like structure is laterally closed, at least in its central section. A beam channel can, in principle, be completely or partially filled with material. Alternatively, it is conceivable that a beam channel is material-free, especially hollow.

[0031] The absorption structure typically exhibits a multitude of cell-like structures, each formed by several different mask walls. These multiple mask walls, in particular, form a multitude of different cell-like structures.

[0032] The cell-like structures of the absorption pattern are arranged within a single plane and / or adjacent to one another. The cell-like structures, or their respective multiple mask walls, are arranged without gaps and / or not stacked on top of each other. The cell-like structures, or their respective multiple mask walls, form the aperiodic pattern in the central section.

[0033] The boundary region of the absorption structure or the scattering mask comprises, in particular, those mask walls and / or cell-like structures that, for example, directly adjoin the outer surface of the scattering mask and / or are clipped and / or bounded by a frame of the scattering mask. In particular, the absorption structure can consist exclusively of cell-like structures that have the same shape and area, wherein only those cell-like structures in the boundary region are reduced in size such that the scattering mask can have a particularly uniform frame in which the absorption structure is embedded. The uniform frame can, in particular, be rectangular, round, oval, or polygonal.

[0034] The multiple mask walls typically consist of materials with a high atomic number and high density. Examples of X-ray-absorbing materials include metals such as lead, or preferably tungsten, tantalum, bismuth, rhenium, osmium, iridium, platinum, thallium, mercury, or gold. These materials effectively absorb X-rays and can thus reduce X-ray scattering.

[0035] The filler material can consist of materials with low atomic numbers, such as plastics like polyethylene, epoxy resin, or polypropylene. These materials exhibit low X-ray attenuation and thus allow a large proportion of the primary X-rays to pass through. Alternatively or additionally, low-density materials such as foams and / or aerogels can also be used. A particularly good option is the use of a support matrix made of a plastic, preferably polyethylene, which is also frequently used in additive manufacturing. Furthermore, polyethylene is suitable as an X-ray-transparent material without the addition of an X-ray-absorbing component.

[0036] The additive manufacturing process enables the precise fabrication of the absorption structure by depositing material layer by layer. This process is carried out, for example, using a so-called "core xy" arrangement. During the fabrication of the scattering mask, the individual layers are built up sequentially. This additive manufacturing process can be a layer-by-layer build-up method, in which the individual layers are applied one after the other. This method allows for precise control over the layer thicknesses and geometries. When depositing a layer, X-ray-absorbing material and, optionally, X-ray-transparent material can be applied alternately. In particular, a layer can consist entirely of X-ray-transparent material or entirely of X-ray-absorbing material.Alternatively, a layer can consist of two or more parts made of X-ray-transparent or X-ray-absorbing material. In particular, it is conceivable that the application of a layer with X-ray-absorbing material is interrupted by material-free sections. Such a layer may not be stable on its own, but achieves sufficient stability when applied to further layers.

[0037] The application of layers can be achieved using various techniques. One possibility is the selective application of material by an application unit, for example, with an application nozzle. The material can be applied in liquid, paste, or powder form, particularly solid, or it can be subsequently cured. Another possibility is the selective solidification of a powder bed by energy input, for example, by a laser (e.g., through selective laser sintering) or another energy source. As a further method, the applied powder can also be cured by a chemical process in which additional material is applied, for example, by applying, particularly by spraying, a liquid, also known as binder jetting. For the application of a layer, it is conceivable that one or both of the material compositions are applied as liquids.In particular, X-ray transparent plastics, such as polyethylene, typically have a relatively low melting point of less than 300°C, while X-ray absorbing materials, such as tungsten, can have comparatively high melting temperatures in the range of well above 1000°C, e.g. tungsten 3422°C.

[0038] Each mask wall can have one or more X-ray-absorbing layers and / or be composed of one or more parts of X-ray-absorbing layers. In particular, a mask wall can consist of a part of one layer or of several parts of different layers. The optional filler material can have one or more X-ray-transparent layers and / or be composed of one or more parts of X-ray-transparent layers. A transition zone between the filler material and one or more mask walls is conceivable, especially with regard to the choice of manufacturing process, for example, due to unwanted contamination and / or for the gradual adjustment of the X-ray attenuation property.The magnitude of the average X-ray attenuation property lies in particular between the low X-ray attenuation property of the filling material and the high X-ray attenuation property of the multiple mask walls.

[0039] The described anti-scatter mask can therefore offer several technical advantages. The use of additive manufacturing allows for very precise control over layer thicknesses and geometries. This can lead to improved efficiency in anti-scatter reduction. Furthermore, the use of alternative materials instead of lead can improve the environmental compatibility of the anti-scatter mask. The ability to fabricate complex structures can also enable optimization of anti-scatter reduction for specific applications in X-ray imaging. The fact that each cell-like structure in the central section has the same shape and area can result in uniform absorption and transmittance across the entire central area of ​​the mask. The combination of these features can lead to improved anti-scatter reduction.The aperiodic pattern can help to reduce, and preferably avoid, artifacts in the X-ray image that can arise from regular structures.

[0040] In another advantageous embodiment of the scattering mask, each cell-like structure in the central section is L-shaped. The L-shaped design of the cell-like structures can offer several advantages. For example, an L-shape can enable efficient use of space, as L-shaped structures can interlock to form a compact arrangement. This can lead to an optimized distribution of the absorption structure across the surface of the scattering mask. Furthermore, the L-shape can improve the stability of the absorption structure, as the two legs of the L can support each other. The L-shape can also offer a variety of orientation possibilities, which can facilitate an aperiodic arrangement of the cell-like structures. This can help reduce unwanted patterning or artifacts in the X-ray image.The L-shaped structures can be implemented in various size ratios and angles, as long as the basic L shape is maintained. By varying these parameters, the absorption characteristics of the scattering mask can be further optimized. The lengths of the two legs of the L-shape can be equal or different.

[0041] In another advantageous embodiment of the scattering mask, the shape of each cell-like structure in the central section is a hat shape. The hat shape can represent a specific geometric configuration resembling a stylized representation of a hat. This hat shape can advantageously be a complex structure that enables efficient coverage of the area while simultaneously favoring an aperiodic arrangement. The hat shape can be designed to provide an optimal balance between X-ray transmittance and absorption. The specific geometry of the hat shape allows the mask walls of the cell-like structures to be arranged to ensure effective scattering suppression while simultaneously allowing sufficient transmission of direct X-rays.A scattering mask with hat-shaped, cell-like structures can offer the advantage of a more uniform distribution of absorption across the entire mask surface. This can lead to improved image quality, as potential artifacts that might arise from regular structures are minimized. Furthermore, the use of hat-shaped structures can facilitate the fabrication of the scattering mask using additive manufacturing processes. The specific shape can be designed to form a stable and self-supporting structure during the manufacturing process, which can improve the precision and reliability of mask production.By arranging hat-shaped cell-like structures in an aperiodic pattern, a scatter radiation mask can be created that has high efficiency in scatter radiation suppression while causing minimal interference with the X-ray image through the mask structure itself.

[0042] In another advantageous embodiment of the scattering mask, the hat shape is composed of 16 right-angled triangles, each of which has the same area. Using a hat shape consisting of 16 right-angled triangles, each with the same area, can offer several advantages. Dividing the mask into triangles of equal size allows for a uniform distribution of the absorbing mask walls across the entire surface of the cell-like structure. This can lead to homogeneous absorption of scattered radiation in all areas of the scattering mask. Furthermore, the arrangement of the 16 right-angled triangles can enable efficient use of the available space. The hat shape can help achieve high absorption of scattered radiation while minimizing interference with direct X-rays.The use of right-angled triangles with the same area can also simplify the fabrication of the scattering mask using additive manufacturing processes. Furthermore, the hat shape composed of 16 right-angled triangles can promote an aperiodic arrangement of the cell-like structures within the scattering mask. This can help reduce unwanted patterns or artifacts in the resulting X-ray image. The composite hat shape of 16 triangles refers to the outer shell of the assembly of 16 triangles, which are arranged seamlessly adjacent to one another in a hat shape. In other words, this embodiment describes a geometric definition of the area and shape of the hat shape. Each cell-like structure still comprises one radiation channel, not 16 radiation channels due to the 16 triangles. The hat shape composed of 16 triangles is, in particular, identical to the hat tile from https: / / www.spektrum.de / news / parkettierung-mathematiker-feiern-hatfest-fuer-einstein-kachel / 2168346.

[0043] In another advantageous embodiment of the scattering mask, each cell-like structure in the central section has a rectangular shape. The rectangular shape of the cell-like structures can offer several advantages. First, a rectangular shape allows for efficient use of space, as rectangular shapes can be arranged seamlessly next to one another. This can lead to optimal utilization of the available space in the absorption structure. Second, a rectangular shape of the cell-like structures can simplify the fabrication of the scattering mask using additive manufacturing processes, since rectangular shapes are often easier to produce than more complex geometric shapes. The rectangular shape can have various aspect ratios, for example, a square or an elongated rectangle.The choice of specific aspect ratio can depend on various factors, such as the requirements for scatter radiation suppression or the manufacturing possibilities. By using rectangular shapes for the cell-like structures, a scatter radiation mask can be created that combines effective scatter radiation suppression with practical manufacturability.

[0044] In another advantageous embodiment of the scattering mask, the rectangular shape is square. The square shape of the cell-like structures can offer several advantages. A square shape allows for a uniform distribution of the absorption structure across the surface of the scattering mask. This can lead to a uniform reduction of scattered radiation over the entire covered area. Furthermore, a square shape of the cell-like structures can facilitate simpler manufacturing using additive manufacturing processes, since right angles can be produced precisely. The square shape can also allow for optimal utilization of the available space within the scattering mask, resulting in an efficient arrangement of the absorption structure.Furthermore, a square shape of the cell-like structures can improve the overall stability of the scattering mask structure, as the forces can be distributed evenly.

[0045] In a further advantageous embodiment of the scattering mask, the cell-like structures are arranged in rows, with adjacent rows being shifted relative to each other longitudinally by a displacement greater than zero. This arrangement can enable improved suppression of scattered radiation. By shifting adjacent rows, an aperiodic configuration of the absorption structure in the central section of the scattering mask can be achieved. The displacement applies to adjacent rows, so that a scattering mask of this embodiment has multiple displacement contributions, which preferably differ in magnitude. A reference point for determining the displacement can be a specific mask wall, a specific point on a mask wall, or a corner of a cell-like structure. The displacement can be selected individually for each pair of rows.In some embodiments, the displacement magnitude can be randomly selected within a predetermined range. The longitudinal direction of the lines can run parallel to an edge of the scattering mask. The described arrangement of the cell-like structures can reduce artifacts in the resulting X-ray images. This embodiment is particularly advantageous in combination with a rectangular or square shape for the cell-like structure. Furthermore, the displacement magnitudes can be used to individualize the scattering mask. This can be advantageous for identification or quality control purposes.

[0046] In another advantageous embodiment of the scattering mask, the radiation channels of the cell-like structures are hollow. This hollow design of the radiation channels can offer several advantages. Firstly, the overall mass of the scattering mask can be reduced by the cavities in the radiation channels, which can facilitate handling and assembly. Secondly, the hollow design can allow for improved transmission of X-rays through the radiation channels, as there is no additional material to attenuate the radiation. This can contribute to improved image quality, as more primary X-rays can reach the X-ray detector. Furthermore, the hollow design of the radiation channels can simplify the fabrication of the scattering mask using additive manufacturing processes, as less material needs to be processed.The hollow beam channels can be created, for example, by selective laser sintering or stereolithography, with the cavities being created directly during the build process.

[0047] In a further advantageous embodiment of the scattering mask, the radiation channels of the cell-like structures comprise an X-ray-transparent material. The filling material can be this X-ray-transparent material. Introducing the filling material into the radiation channels can increase the mechanical stability of the scattering mask. Furthermore, the X-ray-transparent material can help prevent contamination or deposits in the radiation channels.

[0048] In a further advantageous embodiment, the scattering mask also includes a frame in which the absorption structure is inserted. The frame can serve to stabilize and protect the absorption structure. Furthermore, the frame can facilitate easy handling and assembly of the scattering mask. The absorption structure can be permanently or detachably connected to the frame. The frame can be made of a material exhibiting high mechanical stability, such as metal or plastic. In some embodiments, the frame can also be made of an X-ray-transparent material to avoid interfering with the imaging. The use of a frame can enable precise alignment of the absorption structure and fixation in a defined position relative to the X-ray detector. This can contribute to improved image quality and more effective scatter radiation reduction.

[0049] In another advantageous embodiment, the frame is rectangular, with the absorption structure inserted obliquely into the frame. Obliquely means, in particular, that the cut cell-like structures have different surface areas at the edges. In other words, the cell-like structures do not fit directly into the frame but must be trimmed, for example. The oblique insertion can be at any angle suitable for the specific application. The angle can be greater than 0°, for example, and in particular between 1° and 45°. The precise choice of angle may depend on factors such as the size of the cell-like structures, the size of the frame, and the specific requirements for scatter radiation suppression. This arrangement can help to reduce moiré effects that can arise from regular patterns.Furthermore, the angle of oblique insertion can be used to individualize the scattering mask. This can be advantageous for identification or quality control purposes.

[0050] An arrangement according to the invention for an X-ray imaging system has - a scattering radiation mask according to the invention, - an X-ray source, - an X-ray detector and - an examination area between the X-ray source and the X-ray detector, - wherein the scattering mask is arranged between the examination area and the X-ray detector and is aligned such that the stacking direction of the layer stack is parallel to the X-ray detector.

[0051] An X-ray source can be a device that generates X-rays. The X-ray source can be configured to generate X-rays with a specific energy or energy spectrum. The X-ray source can, in particular, be an X-ray tube. The X-ray tube comprises, in particular, an evacuated housing in which an anode and a cathode are arranged. The cathode comprises, in particular, an electron emitter from which free electrons can be accelerated towards the anode. When the accelerated electrons strike the anode, the X-rays are generated. The electron emitter can, in particular, be a cold emitter, for example, a field-effect emitter, or a thermionic emitter, for example, a helical or sheet metal emitter. An X-ray detector can be a device that detects X-rays and converts them into an electrical signal.The X-ray detector can be, for example, a flat-panel detector, a line detector, or a single-pixel detector. It can be made of various materials, such as scintillators in combination with photodetectors or direct-converting semiconductor materials. An examination area can be a space or volume between the X-ray source and the X-ray detector, in which an object to be examined can be placed. The object to be examined can be, for example, a human body, an animal, a technical component, or any other object. For X-ray imaging, a patient is typically located in the examination area. The arrangement of the components can be designed so that the X-ray source emits X-rays that pass through the examination area and strike the X-ray detector.The anti-scatter mask can be positioned between the examination area and the X-ray detector to reduce scatter radiation generated in the examination area.

[0052] Since the arrangement according to the invention includes the anti-scatter mask according to the invention, it shares the advantages described above. Aligning the anti-scatter mask with the stacking direction of the layer stack parallel to the X-ray detector can serve to optimize the efficiency of the anti-scatter reduction. The described arrangement for X-ray imaging can enable improved image quality by effectively reducing the scatter radiation. The precise positioning and alignment of the anti-scatter mask with respect to the X-ray detector and the examination area can lead to optimized anti-scatter reduction while simultaneously minimizing the absorption of the primary X-ray radiation.

[0053] The arrangement according to the invention is particularly suitable for medical or technical X-ray imaging. Applications of medical X-ray imaging include, in particular, angiography, computed tomography, mammography, and / or fluoroscopy. Applications of technical X-ray imaging include, in particular, materials testing, security inspections, and / or customs inspections.

[0054] An X-ray imaging system can comprise the arrangement according to the invention as well as, for example, at least one control computer which can control the X-ray source for X-ray imaging. The X-ray imaging system can be designed, in particular, for medical and / or technical X-ray imaging.

[0055] In a further advantageous embodiment, the X-ray detector comprises multiple detector cells, wherein the shape of the cell-like structures of the scattering mask has a larger area than the shape of the multiple detector cells. In other words, a detector cell of the multiple detector cells is smaller than a cell-like structure of the scattering mask, which is generally advantageous. This arrangement can also be advantageous because the larger cell-like structures of the scattering mask can provide effective scattering suppression, while at the same time a high spatial resolution of the X-ray detector can be maintained by the smaller detector cells. A cell-like structure of the scattering mask can be dimensioned to cover more than one detector cell. This can enable an optimal balance between scattering suppression and detector resolution.The detector cells can, for example, have a square or rectangular shape, while the cell-like structures of the scattering mask can have any of the previously described shapes, such as L-shaped, hat-shaped, or rectangular. The larger surface area of ​​the cell-like structures can help to effectively absorb scattered radiation before it reaches the detector cells. By combining smaller detector cells with larger cell-like structures of the scattering mask, improved image quality can be achieved while simultaneously providing effective scatter suppression. This can be particularly advantageous for medical X-ray imaging applications where both high detail resolution and good contrast are required.

[0056] A system for the additive manufacturing of a scattering mask for reducing X-ray scattering, particularly for X-ray imaging, comprises an application unit configured to produce the scattering mask according to the invention using an additive manufacturing process. An application unit can be a device configured to apply material layer by layer to create a three-dimensional structure. The application unit can include various components, such as one or more application nozzles, extruders, lasers, power sources, or other mechanisms for the precise application of material. The application unit can be configured to process and apply different materials. The application unit can have mechanisms for switching between different materials or for applying several materials simultaneously.Such a system for the additive manufacturing of a scattering mask can offer a high degree of manufacturing flexibility. The geometry and composition of the scattering mask can be easily adapted to meet various requirements in X-ray imaging. Furthermore, additive manufacturing can enable the production of complex internal structures that would be difficult to create using conventional manufacturing methods.

[0057] The inventive method for producing a scattering radiation mask comprises the following steps: - Manufacturing the scattering radiation mask using an additive manufacturing process, - Capturing an image of the absorption structure of the manufactured scattering mask using a sensor unit, - Determining at least one geometric parameter of the absorption structure in the captured image using a pattern recognition unit, - Assigning an identification string to the manufactured scattering mask, - Storing the determined at least one geometric parameter as a geometric reference parameter and the associated identification string in a storage unit for identifying the scattering radiation mask.

[0058] After the anti-scattering mask is fabricated, an image of the absorption structure is acquired. The sensor unit for acquiring the image can be a camera, an X-ray detector, or another imaging device. The image shows, in particular, the X-ray-absorbing mask walls or the cell-like structures of the anti-scattering mask. The sensor unit can include a processing unit.

[0059] The pattern recognition unit is designed to determine at least one geometric parameter of the absorption structure in the acquired image using a processing unit. Geometric parameters can include, for example, the shape, size, or arrangement of the cell-like structures, the thickness of the mask walls, and / or the displacement contributions and / or the orientation, i.e., the angle of oblique insertion, of the aperiodic pattern. Alternatively or additionally, the geometric parameter can be a kind of fingerprint of the scattering mask. The pattern recognition unit can include image processing software or a specially trained algorithm for analyzing the absorption structure. The pattern recognition unit can include a processing unit or be part of one. In particular, the pattern recognition unit can be connected to the sensor unit for transferring the acquired image.

[0060] A unique identification string is assigned to the manufactured scattering mask, for example, by means of a processing unit. This string can be a serial number, an alphanumeric code, and / or another unique identifier. The assignment can preferably be performed automatically by a processing unit or manually by an operator.

[0061] The determined geometric parameter and the associated identification string are stored in a storage unit. This storage unit can be one or more databases, one or more memory chips, or another digital storage medium. The storage unit can be partially or entirely cloud-based. This stored information enables subsequent identification of the specific scattering mask.

[0062] This inventive method allows each manufactured scattering mask to be uniquely identified. This can be useful for quality control, traceability, or the assignment of X-ray images to specific scattering masks. Furthermore, storing the geometric parameters can enable subsequent analysis or optimization of the manufacturing process. The individualization of the masks can function as a kind of quasi-digital watermark. This opens up possibilities for advanced business models, such as pay-per-use. In such a model, the use of a specific scattering mask can be tracked and billed by identifying the mask in the acquired X-ray images.

[0063] The inventive method for identifying a scattering radiation mask comprises the following steps: - Capturing an image of an absorption structure of the scattering radiation mask using a sensor unit, - Determining at least one geometric parameter of the absorption structure in the captured image using a pattern recognition unit, - Determining a geometric reference parameter retrievable from a storage unit as a function of the determined at least one geometric parameter using a computing unit, - Providing the identification string that is assigned to the determined geometric reference parameter, thereby identifying the scattering radiation mask.

[0064] Determining the geometric reference parameter can involve filtering and / or comparing the determined geometric parameter with one, some, or all reference parameters. Advantageously, exactly one reference parameter is determined during the process. The determined reference parameter preferably exhibits the highest degree of agreement, for example, 100% agreement, with the determined geometric parameter.

[0065] Providing the identification string can involve transmitting the identification string via a network connection, displaying the identification string on a display unit, and / or outputting a signal containing the identification string via an output unit. The output unit can include an analog or digital interface.

[0066] The identification string is provided, in particular, by a processing unit. The identification string is provided, for example, to and / or transmitted to an imaging billing unit. The imaging billing unit can, for example, assign and / or link an X-ray imaging examination protocol and / or a numerical value to the identification string. The imaging billing unit can be part of a processing unit and / or a protocol unit. An X-ray imaging system typically includes the processing unit and / or the protocol unit. The protocol unit can be specifically designed for recording a radiation dose and / or an imaging parameter of the X-rays.

[0067] This method according to the invention enables the identification of individualized scattering radiation masks. By detecting and analyzing these individual characteristics, each scattering radiation mask can be uniquely identified.

[0068] The computer program product can be a computer program or comprise a computer program. The computer program product particularly includes the program code means that implement the process steps according to the invention. This allows the process according to the invention to be defined and executed repeatably, and enables control over the transfer of the process according to the invention. The computer program product is preferably configured such that the computing unit can execute the process steps according to the invention by means of the computer program product. The program code means can, in particular, be loaded into a memory of the computing unit and typically executed by means of a processor of the computing unit with access to the memory.When the computer program product, in particular the program code, is executed in the processing unit, all embodiments of the described method according to the invention can typically be carried out. The computer program product is, for example, stored on a physical, computer-readable medium and / or digitally stored as a data packet in a computer network. The computer program product can represent the physical, computer-readable medium and / or the data packet in the computer network. Thus, the invention can also start from the physical, computer-readable medium and / or the data packet in the computer network. The physical, computer-readable medium is usually directly connectable to the processing unit, for example, by inserting the physical, computer-readable medium into a DVD drive or plugging it into a USB port, thereby allowing the processing unit to access the physical, computer-readable medium, particularly for reading.The data packet can preferably be retrieved from the computer network. The computer network can contain the computing unit itself or be indirectly connected to the computing unit via a wide-area network (WAN) or a (wireless) local area network (WLAN or LAN) connection. For example, the computer program product can be stored digitally on a cloud server at a storage location within the computer network and transferred to the computing unit via the WAN over the internet and / or via WLAN or LAN, particularly by accessing a download link that points to the storage location of the computer program product.

[0069] Features, advantages, or alternative embodiments mentioned in the description of the device are also transferable to the method, and vice versa. In other words, claims relating to the method can be further developed with features of the device, and vice versa. In particular, the device according to the invention can be used in the method.

[0070] Regardless of the grammatical gender of a particular term, persons with male, female or other gender identities are included.

[0071] The invention will now be described and explained in more detail with reference to the exemplary embodiments shown in the figures. In principle, structures and units that remain essentially the same in the following figure descriptions will be named with the same reference numeral as when the respective structure or unit first appears.

[0072] They show: Fig. 1 a schematic sectional view of an arrangement for X-ray imaging, Fig. 2 a schematic sectional view of an arrangement for X-ray imaging with an object in the examination area, Fig. 3 a schematic sectional view of an arrangement according to the invention for X-ray imaging with a scattering radiation mask, Fig. 4 a schematic sectional view of a first embodiment of an arrangement according to the invention for X-ray imaging with a scattering mask, Fig. 5 - 7 a schematic top view of periodic scattering radiation masks, Fig. 8 a schematic top view of a first variant of a scattering radiation mask according to the invention, Fig. 9 a schematic top view of a second variant of the scattering radiation mask according to the invention, Fig. 10 a detailed view of a cell-like structure with a special hat shape, Fig. 11 a schematic top view of a third variant of the scattering radiation mask according to the invention, Fig. 12 a schematic top view of a first embodiment of the third variant of the scattering radiation mask according to the invention, Fig. 13 a flowchart of a process for manufacturing a scattering radiation mask and Fig. 14 a flowchart of a procedure for identifying a scattering radiation mask.

[0073] Fig. Figure 1 shows a schematic sectional view of an arrangement 20 for X-ray imaging.

[0074] The arrangement 20 comprises an X-ray source 21 and an X-ray detector 22. The X-ray source 21 is arranged above the X-ray detector 22. An examination area 23 is provided between the X-ray source 21 and the X-ray detector 22, in which an object to be examined can be placed, but in Fig. 1 is not placed. The X-ray detector 22 is positioned below the examination area 23.

[0075] The X-rays emitted by the X-ray source 21 can pass through the examination area 23 and reach the X-ray detector 22. The path of the X-rays from the X-ray source 21 to the X-ray detector 22 is shown by dashed lines. The X-rays of the Fig. 1. These are exclusively primary X-rays because they are not scattered in an object. The trajectories of the X-ray photons are therefore perfectly straight.

[0076] Fig. Figure 2 shows a schematic sectional view of an arrangement 20 for X-ray imaging with an object in the examination area 23.

[0077] The object is depicted as an oval shape. Some of the X-rays, represented by the dashed lines, are scattered within the object. In addition to the primary X-rays, scattered X-rays also strike the X-ray detector 22. Scattered X-ray photons exhibit in Fig. 2 a dashed line with a bend.

[0078] Fig. Figure 3 shows a schematic sectional view of an arrangement 20 according to the invention for X-ray imaging with a scattering mask 10.

[0079] The arrangement 20 according to the invention comprises the X-ray source 21, the examination area 23, a scattering mask 10, and the X-ray detector 22. The examination area 23 is located between the X-ray source 21 and the X-ray detector 22. The scattering mask 10 is arranged between the examination area 23 and the X-ray detector 22 and is oriented such that the stacking direction 15 of the layer stack 11 is parallel to the X-ray detector 22. The scattering mask 10 is arranged below the examination area 23. The X-ray detector 22 is arranged at the lower part of the illustration and is positioned so that it can detect, in particular, primary X-rays passing through the examination area 23 and the scattering mask 10. The X-ray detector has several detector cells. Fig. 3. The shape of the cell-like structures of the scattering mask has a smaller area than the shape of the multiple detector cells.

[0080] Fig. Figure 4 shows a schematic sectional view of a first embodiment of an arrangement according to the invention for X-ray imaging with a scattering radiation mask. Fig. 4 The shape of the cell-like structures of the scattering mask has a larger area than the shape of the multiple detector cells.

[0081] Fig. 5, Fig. 6 to Fig. Figure 7 shows a schematic top view of periodic scattering radiation masks, where the shape of the cell-like structures is a triangle ( Fig. 5), a square ( Fig. 6) and a hexagon ( Fig. 7) is.

[0082] Fig. Figure 8 shows a schematic top view of a first variant of a scattering radiation mask according to the invention.

[0083] The anti-scatter mask 10 for reducing X-ray scatter radiation, particularly for X-ray imaging, has an absorption structure 11 manufactured using an additive manufacturing process. The absorption structure 11 exhibits an aperiodic pattern in a central section, which is not a boundary region. The absorption structure 11 comprises X-ray-absorbing mask walls. Several mask walls together form a cell-like structure 12.1 ... 12.N with a laterally enclosed, X-ray-transparent beam channel. In the central section, each cell-like structure 12.1 ... 12.N has the same shape and area. The shape of each cell-like structure 12.1 ... 12.N in the central section in the first variant is L-shaped. The beam channels of the cell-like structures 12.1 ... 12.N can be made of an X-ray-transparent material or, alternatively, be hollow.

[0084] Fig. Figure 9 shows a schematic top view of a second variant of the scattering radiation mask 10 according to the invention. The shape of each cell-like structure 13.1 ... 13.N in the central section is a hat shape or single-tile shape. The radiation channels of the cell-like structures 13.1 ... 13.N can be made of an X-ray-transparent material or alternatively be hollow.

[0085] Fig. Figure 10 shows a detailed view of a cell-like structure with a special hat shape as a single tile form. The hat shape of the cell-like structure 13.1 is composed of 16 right-angled triangles, each with the same area. At least the Fig. 10 is to scale.

[0086] Fig. Figure 11 shows a schematic top view of a third variant of the scattering radiation mask according to the invention. The shape of each cell-like structure 14.1 ... 14.N in the central section is rectangular or square. The cell-like structures 14.1 ... 14.N are arranged in rows. Adjacent rows are shifted relative to each other longitudinally by a displacement greater than zero. The radiation channels of the cell-like structures 14.1 ... 14.N can be made of an X-ray-transparent material or, alternatively, be hollow.

[0087] Fig. Figure 12 shows a schematic top view of a first embodiment of the third variant of the scattering radiation mask according to the invention.

[0088] The scattering mask 10 further comprises a frame 15. The absorption structure 11 is inserted into the frame 15. The frame 15 is rectangular. The absorption structure 11 is inserted obliquely into the frame 15.

[0089] Fig. Figure 13 shows a flowchart of a process for manufacturing a scattering radiation mask with steps S100 to S104.

[0090] Process step S100 describes the production of the scattering radiation mask using an additive manufacturing process.

[0091] Process step S101 describes the acquisition of an image of an absorption structure of the manufactured scattering radiation mask using a sensor unit.

[0092] Procedure step S102 characterizes the determination of at least one geometric parameter of the absorption structure in the captured image using a pattern recognition unit.

[0093] Process step S103 marks the assignment of an identification string to the manufactured scattering radiation mask.

[0094] Procedure step S104 characterizes the storage of the determined at least one geometric parameter as a geometric reference parameter and the associated identification string in a storage unit for the identification of the scattering radiation mask.

[0095] Fig. Figure 14 shows a flowchart of a procedure for identifying a scattering radiation mask with steps S200 to S203.

[0096] Process step S200 characterizes the acquisition of an image of an absorption structure of the scattering radiation mask using a sensor unit.

[0097] Procedure step S201 characterizes the determination of at least one geometric parameter of the absorption structure in the captured image using a pattern recognition unit.

[0098] Procedure step S202 characterizes the determination of a geometric reference parameter retrievable from a storage unit as a function of the determined at least one geometric parameter using a computing unit.

[0099] Procedure step S203 marks the provision of the identification string that is assigned to the determined geometric reference parameter, thereby identifying the scattering radiation mask.

[0100] Although the invention has been illustrated and described in detail by the preferred embodiments, the invention is nevertheless not limited by the disclosed examples and other variations can be derived by the person skilled in the art without leaving the scope of protection of the invention. QUOTES INCLUDED IN THE DESCRIPTION

[0000] This list of documents cited by the applicant was automatically generated and is included solely for the reader's convenience. The list is not part of the German patent or utility model application. The DPMA accepts no liability for any errors or omissions. Cited patent literature

[0000] DE 103 05 106 A1

[0005] US 4133152

[0006] Cited non-patent literature

[0000] https: / / www.spektrum.de / news / parkettierung-mathematiker-feiern-hatfest-fuer-einstein-ka-

[0007] https: / / www.spektrum.de / news / parkettierung-mathematiker-feiern-hatfest-fuer-einstein-kachel / 2168346

[0042]

Claims

[1] Scattering mask (10) for reducing X-ray scattering, especially for X-ray imaging, comprising - an absorption structure (11) produced by an additive manufacturing process, which has an aperiodic pattern in a central section that is not a boundary region, - wherein the absorption structure (11) comprises X-ray-absorbing mask walls, - wherein several mask walls each form a cell-like structure (12.1 ... 12.N, 13.1 ... 13.N, 14.1 ... 14.N) with a laterally enclosed, X-ray-transparent beam channel, characterized by , that in the central section each cell-like structure (12.1 ... 12.N, 13.1 ... 13.N, 14.1 ... 14.N) has the same shape and the same area. [2] Scattering radiation mask (10) according to claim 1, wherein the shape of each cell-like structure (12.1 ... 12.N) in the central section is an L-shape. [3] Scattering radiation mask (10) according to claim 1, wherein the shape of each cell-like structure (13.1 ... 13.N) in the central section is a hat shape. [4] Scattering radiation mask (10) according to claim 3, wherein the hat shape is composed of 16 right-angled triangles, each with the same area. [5] Scattering radiation mask (10) according to claim 1, wherein the shape of each cell-like structure (14.1 ... 14.N) in the central section is a rectangular shape. [6] Scattering radiation mask (10) according to claim 5, wherein the cell-like structures (14.1 ... 14.N) are arranged in rows, wherein adjacent rows are shifted relative to each other in the longitudinal direction by a displacement amount greater than zero. [7] Scattering radiation mask (10) according to one of claims 5 or 6, wherein the rectangular shape is a square shape. [8] Scattering radiation mask (10) according to one of the preceding claims, wherein the radiation channels of the cell-like structures (12.1 ... 12.N, 13.1 ... 13.N, 14.1 ... 14.N) are hollow. [9] Scattering mask (10) according to any one of claims 1 to 7, wherein the radiation channels of the cell-like structures (12.1 ... 12.N, 13.1 ... 13.N, 14.1 ... 14.N) comprise an X-ray transparent material. [10] Scattering radiation mask (10) according to one of the preceding claims, wherein the scattering radiation mask (10) further comprises a frame (15) in which the absorption structure (11) is inserted. [11] Scattering radiation mask (10) according to claim 10, wherein the frame (15) is rectangular and the absorption structure (11) is inserted obliquely into the frame (15). [12] Arrangement (20) for X-ray imaging, comprising - a scattering radiation mask (10) according to any one of the preceding claims, - an X-ray source (21), - an X-ray detector (22) and - an examination area (23) between the X-ray source (21) and the X-ray detector (22), - wherein the scattering mask (10) is arranged between the examination area (23) and the X-ray detector (22) and is aligned parallel to the X-ray detector (22). [13] Arrangement (20) according to claim 12, wherein the X-ray detector (22) has several detector cells and wherein the shape of the cell-like structures (12.1 ... 12.N, 13.1 ... 13.N, 14.1 ... 14.N) of the scattering mask (10) has a larger area than the shape of the several detector cells. [14] Method for producing a scattering radiation mask according to any one of claims 1 to 11, comprising the steps: - Manufacturing the scattering radiation mask using an additive manufacturing process, - Capturing an image of the absorption structure of the manufactured scattering mask using a sensor unit, - Determining at least one geometric parameter of the absorption structure in the captured image using a pattern recognition unit, - Assigning an identification string to the manufactured scattering mask, - Storing the determined at least one geometric parameter as a geometric reference parameter and the associated identification string in a storage unit for identifying the scattering radiation mask. [15] Method for identifying a scattering radiation mask according to any one of claims 1 to 11, comprising the steps: - Capturing an image of an absorption structure of the scattering radiation mask using a sensor unit, - Determining at least one geometric parameter of the absorption structure in the captured image using a pattern recognition unit, - Determining a geometric reference parameter retrievable from a storage unit as a function of the determined at least one geometric parameter using a computing unit, - Providing the identification string that is assigned to the determined geometric reference parameter, thereby identifying the scattering radiation mask.

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