DE202023105478U1 - Anti-scatter filter, X-ray detector device, medical imaging device and computed tomography system - Google Patents

Abstract

Scattered radiation filter for an X-ray detector (4),
wherein the anti-scatter filter has a collimator element (2) with a plurality of collimator walls (1) and at least one alignment element (AE1, AE2, AE3),
wherein the collimator walls (1) are arranged in a grid-like manner, crossed relative to one another, in a collimator surface that is transverse to a first spatial direction, so that a plurality of radiation channels (3) extending elongated in the first spatial direction are formed between the crossed collimator walls (1), and wherein the collimator surface of is limited by external walls (AW) formed by collimator walls arranged on the outside,
wherein the at least one alignment element (AE1, AE2, AE3) is designed as a structural element, having at least two adjacent and non-parallel contact surfaces, on an outside of at least one of the outer walls (AW) of the collimator element (2),
wherein an absorption capacity for X-rays of the at least one outer wall (AW) is not reduced compared to the remaining collimator walls (1) by the alignment element (AE1, AE2, AE3),
wherein the contact surfaces of the at least one alignment element (AE1, AE2, AE3) are designed to align the anti-scatter filter in the first and/or at least one further spatial direction.

Description

The invention relates to an anti-scatter radiation filter, an X-ray detector device, a medical imaging device and a computer tomography system.

X-ray imaging devices (in short: X-ray devices) usually have an X-ray source and an X-ray detector (in short: X-ray detector), which are arranged opposite one another. During operation of the X-ray device, the X-ray radiation emitted by the X-ray source and possibly partially attenuated by an examination object, for example a patient and/or an examination phantom and/or a workpiece, is detected by means of the X-ray detector. The X-ray detector is set up to output a (measuring) signal corresponding to the intensity of the incident X-rays. In particular, the X-ray detector has a large number of image points, in particular pixels and/or voxels, which serve to detect the intensity distribution of the incident X-radiation in a surface-resolved manner. Optionally, the X-ray detector is divided into a plurality of detector elements, each of which comprises a plurality of image points, in particular pixels. This means that large-area X-ray detectors that are curved, for example for use in computer tomography, can be easily formed by arranging the detector elements in a row (“tiling”).

During operation of the X-ray device, the X-rays emitted by the X-ray source are not only attenuated to varying degrees by the object under examination, but are also partially scattered at an angle to the original radiation direction, which usually runs radially to the X-ray source. When they strike the X-ray detector, these scattered rays (“scattered rays”) cause a falsification of the image reconstructed from the intensity distribution due to their superimposition with the (main) X-rays striking in the original radiation direction. In particular, these scattered rays lead to a reduction in the contrast of the reconstructed image.

To reduce the influence of scattered radiation, an X-ray detector is often assigned a so-called scattered radiation filter (also referred to as an “anti-scatter grid”), which is connected upstream of the X-ray-sensitive elements of the X-ray detector in the direction of radiation. Such scattered radiation filters usually have a grid-like structure, with each grid opening forming a type of radiation channel that runs in the direction of the main X-rays. The individual radiation channels are divided by walls that are made of an X-ray absorbing material. In most cases, each radiation channel is assigned to a single pixel or at least a small number of pixels. The radiation channels are also elongated, in particular with a length that is many times greater in the direction of the main X-rays than an extension transverse to the direction of the main X-rays. This advantageously ensures that scattered rays deviating from the direction of the main X-rays strike the walls surrounding the radiation channels and are absorbed by them.

Since the individual pixels of an the pixels of the X-ray detector are desirable.

A detector element often includes the anti-scatter filter, a sensor and an application specific integrated circuit for digitization (ASIC). In integrating systems, the sensor can include a photodiode. A respective detector element can extend over several sensors, in particular in the z-direction of a computer tomograph (“bridge design”). For this purpose, the anti-scatter filter must be aligned in a longitudinal and transverse direction to a device or to an surrounding structure with the aim of achieving the most precise alignment possible with the sensors during assembly. When aligning the anti-scatter filter, very tight tolerances must be maintained in relation to the sensors underneath. For this purpose, stop surfaces or shaped elements, for example a bore and/or an elongated hole, are often introduced into the anti-scatter filters. Stop surfaces and alignment elements must have a high level of precision in order to be able to maintain the required tolerances when installing the anti-scatter filter on the sensor or sensors. The stop surfaces must also be free of adhesions, which can occur, for example, in 3D-printed anti-scatter filters made of tungsten powder. Typically, the shaped elements are inserted into the scattered radiation filters made from tungsten powder using 3D printing (selective laser melting) using wire erosion. In order to place the shaped elements as precisely as possible on the inner walls of the anti-scatter filter, it is often necessary technically complex, multi-stage process with measurement required.

It is therefore the object of the present invention to provide a precisely alignable and efficiently manufactured anti-scatter radiation filter.

The problem is solved according to the invention by the subject matter of the independent claims. Advantageous embodiments with useful further developments are the subject of the subclaims. Regardless of the grammatical gender of a particular term, it includes people with male, female or other gender identities.

In a first aspect, the invention relates to a scattered radiation filter for an X-ray detector. The anti-scatter filter has a collimator element with a plurality of collimator walls and at least one alignment element. The collimator walls are arranged in a grid-like manner, crossed relative to one another, in a collimator surface that is transverse to a first spatial direction, so that a plurality of radiation channels extending elongated in the first spatial direction are formed between the crossed collimator walls. Furthermore, the collimator surface is delimited by outer walls formed by collimator walls arranged on the outside. Furthermore, the at least one alignment element is designed as a structural element, having at least two adjacent and non-parallel contact surfaces, on an outside of at least one of the outer walls of the collimator element. An absorption capacity for X-rays of the at least one outer wall is not reduced by the alignment element compared to the remaining collimator walls. Preferably, a thickness of the outer wall, in particular at least perpendicular to the first spatial direction, at the location of the at least one alignment element is at least as large as the remaining collimator walls. Alternatively, the outer wall can have a smaller thickness than the remaining collimator walls, in particular at least perpendicular to the first spatial direction, and can comprise a material with a correspondingly higher absorption capacity for X-rays compared to the remaining collimator walls, in particular be formed from this material. Furthermore, the contact surfaces of the at least one alignment element are designed to align the anti-scatter filter in the first and/or at least one further spatial direction.

The anti-scatter radiation filter according to the invention is set up and intended for use on an X-ray detector of an X-ray machine. For this purpose, the anti-scatter filter comprises a plurality of collimator walls which are arranged in a grid-like manner, crossed relative to one another, in the collimator surface which is transverse to the first spatial direction, so that a plurality of radiation channels running elongated in the first spatial direction are formed between the crossed collimator walls. The grid-like crossed arrangement can, for example, include corner angles between intersecting collimator walls of equal or unequal 90 degrees or grids of polygons, in particular hexagons. The collimator surface is delimited by outer walls formed by collimator walls arranged on the outside. This means that the collimator walls delimiting the collimator surface on the outside are referred to here and below as outer walls.

The anti-scatter filter has at least one alignment element, in particular a plurality of alignment elements, which is designed as a structural element adjacent to an outside of at least one of the outer walls of the collimator element. In particular, the at least one alignment element can be formed as a structural element on the outside of the at least one outer wall by the outer wall, in particular a substrate of the outer wall. The structural element can be designed as a three-dimensional (3D) structure, for example a survey and/or recess, on the outside of the at least one outer wall. In particular, the at least one alignment element can be formed by a 3D structure of the substrate of the outer wall. The outside of the outer wall can designate a side and/or surface of the outer wall, in particular the outer collimator wall, which faces away from the remaining, in particular inner, collimator walls.

The collimator walls preferably have a material which strongly absorbs X-rays, for example a metallic material, in particular tungsten. The absorption capacity for X-rays of the at least one outer wall, on which the at least one alignment element is formed, can be undiminished by the alignment element compared to the remaining, in particular the inner, collimator walls. This can be achieved in particular in that the at least one outer wall has a greater wall thickness than the remaining collimator walls, at least in the area of the alignment element.

The at least one alignment element can have at least two contact surfaces which adjoin one another and do not run parallel to one another. The at least two contact surfaces can each be arranged at a predefined angle with respect to the first spatial direction, in particular a right angle or parallel to the first spatial direction.

The term “essentially” here and below is understood to mean exactly or approximately, ie, for example, within the range of usual manufacturing tolerances or with deviations of a maximum of 5%.

In a simple approximation, the first spatial direction is a coordinate of a Cartesian coordinate system. Preferably, however, the first spatial direction is a direction emanating in the form of a radial ray from a starting point remote from the anti-scatter filter, which thus extends on a flat plane that is transverse to this spatial direction at a different angle at every point on this plane - but on the Aligning the starting point - stands up. In this case, the first spatial direction preferably corresponds to an X-ray direction of a fan-like X-ray beam emanating from a (in particular approximately point-shaped) X-ray source during operation of the X-ray device comprising the Therefore, in the latter case, adjacent collimator walls are preferably inclined in such a way that the radiation channels formed between the crossed collimator walls, when installed as intended in the X-ray device, each taper conically towards the X-ray source or are at least inclined towards it. The collimator surface of the anti-scatter filter is in particular radial to this first spatial direction and forms, for example, a type of tangential surface. Optionally, the collimator surface is also curved comparable to the lateral surface of a circular cylinder. This is particularly useful in the case that the X-ray detector of the X-ray device, for example a computer tomograph, is also curved like a lateral surface, so that the partial X-rays emanating from the X-ray source always strike normal to the detector surface, because then the anti-scatter filter can be placed particularly easily and over the entire surface of the X-ray detector and be fixed to this.

The term “elongated” is understood here and below in particular to mean that the collimator walls are designed in such a way that the radiation channels arranged between the crossed collimator walls have a length-to-width ratio (seen in the first spatial direction) of greater than or equal to 5: 1 have. This enables sufficient absorption of scattered radiation by the scattered radiation filter.

The term “post-processing-free” is understood here and below in particular to mean that the original molding process enables finished or near-net-shape production of the anti-scatter radiation filter - at least its respective layer. Specifically, it is understood here and below that there are no longer any manufacturing steps downstream of the original molding process to form the intended contours of the anti-scatter filter or the individual layer of the anti-scatter filter. However, sprues and/or risers that are often present in a primary molding process can still be removed.

The anti-scatter filter, specifically its detector surface, is preferably designed as a polygonal shape, for example rectangular or triangular or hexagonal. Due to the polygonal shape, in particular rectangular shape, several scattered radiation filters can advantageously be arranged next to one another in a particularly simple manner - like a tile - to form a particularly large overall area.

The post-processing-free original molding process also enables precise formation of the collimator walls and thus also of the at least one alignment element, in particular the at least two contact surfaces, without the need for additional post-processing steps that increase production costs. By means of the at least one alignment element, a precise and robust alignment of the anti-scatter filter can advantageously be made possible.

In a further advantageous embodiment of the proposed anti-scatter filter, the collimator walls can additionally be arranged essentially parallel to one another and parallel to the first spatial direction.

In particular, the grid-like crossed arrangement of the collimator walls can have corner angles of 90 degrees. The radiation channels can also have a substantially rectangular, in particular square, cross section. This makes it possible to improve the illumination of the detector pixels, in particular rectangular and/or square ones, from X-rays passing through the radiation channels.

In a further advantageous embodiment of the proposed anti-scatter filter, the at least one alignment element can be designed as a survey and/or recess on an outside of the at least one outer wall of the collimator element.

The at least one alignment element, in particular the plurality of alignment elements, can each be designed as a recess, in particular a groove and/or step, and/or an elevation, for example a spring and/or a rod and/or pin.

The proposed embodiment can advantageously enable precise alignment of the anti-scatter filter with respect to a further component by positive contact of the at least two contact surfaces, each with a corresponding contact surface of the further component. Advantageously, the introduction of shaped elements, for example a bore and/or an elongated hole, on a flange of the anti-scatter filter can be omitted. Process steps for a defined wire erosion of the shaped elements are advantageously not required in the anti-scatter filter according to the invention. As a result, production of the anti-scatter filter can be simplified and made cost-effective.

In a further advantageous embodiment of the proposed anti-scatter filter, the at least one alignment element can be designed as a stepped section on an outside of the at least one outer wall of the collimator element. Two of the at least two contact surfaces, which are arranged at an angle to one another, can form the stepped section.

The stepped section can comprise at least two contact surfaces arranged at an angle to one another, in particular perpendicularly. Advantageously, an edge at which the two contact surfaces meet can run perpendicular or parallel to the first spatial direction.

The proposed embodiment can advantageously enable a precise, in particular geometrically defined, alignment of the anti-scatter filter with respect to a further component in two spatial directions by positive contact of the at least two contact surfaces, each with a corresponding contact surface of the further component.

In a further advantageous embodiment of the proposed anti-scatter filter, the at least one alignment element can extend over an entire width and/or height of the at least one outer wall.

Advantageously, the outer wall can have a substantially rectangular and/or trapezoidal outer surface on the outside. The width of the outer wall can denote an extension of the outer wall in a further spatial direction that is essentially perpendicular to the first spatial direction. Furthermore, the height of the outer wall can indicate an extension of the outer wall essentially parallel to the first spatial direction.

The at least one alignment element, in particular the at least two contact surfaces, can advantageously extend, in particular extend, over the entire width and/or height of the at least one outer wall. The at least one alignment element can be arranged on an edge and/or on a surface of the at least one outer wall.

The proposed embodiment can advantageously enable more degrees of freedom of movement when aligning the anti-scatter filter.

In a further advantageous embodiment of the proposed anti-scatter filter, the anti-scatter filter can have a plurality of alignment elements which are at least partially, in particular completely, identical.

The plurality of alignment elements can each be formed as a structural element on the outside of an outer wall or a plurality of outer walls of the collimator element. The plurality of alignment elements can be designed to be the same, at least partially, in particular completely, with regard to a 3D structure, for example a shape and/or arrangement of contact surfaces and/or extent and/or orientation. In particular, the alignment elements can be designed the same on opposite outer walls of the collimator element.

The proposed embodiment can advantageously enable precise alignment of the anti-scatter filter with respect to a further component in several spatial directions by positive contact of the several contact surfaces with a corresponding contact surface of the further component.

In a further advantageous embodiment of the proposed anti-scatter filter, the anti-scatter filter can have a plurality of alignment elements which are at least partially, in particular completely, designed differently.

The plurality of alignment elements can each be formed as a structural element on the outside of an outer wall or a plurality of outer walls of the collimator element. The plurality of alignment elements can be designed differently with regard to a 3D structure, for example a shape and/or arrangement of contact surfaces and/or extent and/or orientation, at least partially, in particular completely.

The proposed embodiment can advantageously enable a precise alignment of the anti-scatter filter with respect to a further component in several spatial directions by positively abutting the several contact surfaces with one each enable corresponding contact surface of the further component.

In a further advantageous embodiment of the proposed anti-scatter filter, the at least one alignment element can at least adjoin an edge of the at least one outer wall of the collimator element.

Advantageously, the at least one outer wall of the collimator element can have at least one edge, in particular a plurality of edges, which spatially delimit the outside, in particular an outer surface, of the outer wall. The at least one alignment element can be arranged on the edge, in particular immediately adjacent to the edge or comprising the edge, in particular forming the edge, on the at least one outer wall of the collimator element. The at least one alignment element can thus at least border the edge of the at least one outer wall of the collimator element.

The proposed embodiment can advantageously enable more degrees of freedom of movement when aligning the anti-scatter filter.

In a further advantageous embodiment of the proposed anti-scatter filter, the collimator element and the at least one alignment element can be formed in one piece.

By producing a collimator element in one piece, in particular in one piece, construction effort in assembling the collimator element and the at least one alignment element from individual parts can advantageously be avoided. For example, this can save material and fasteners and time-consuming processing steps.

In a further advantageous embodiment of the proposed anti-scatter filter, the collimator element and the at least one alignment element can be produced using an additive manufacturing technique.

Additive manufacturing technology involves a process in which a component is built layer by layer by depositing material based on digital 3D design data. This allows a high degree of variability in the design. This advantageously enables time-efficient production and resource-saving production of even complex but at the same time stable structures and shapes. Depending on the raw material and application, the components can be manufactured using stereolithography, laser sintering or 3D printing. Various metals, plastics and composite materials are available as materials.

For example, the collimator element and the at least one alignment element can be produced using selective laser melting or laser sintering. A powder material comprising a metal powder is preferably used. First, a thin layer of the powder material is applied to a construction platform. Using a laser, the powder can be melted exactly at the points specified by the computer-generated component design data. The production platform then lowers and another powder application takes place. The material is melted again and bonds to the underlying layer at defined points.

Advantageously, a high volume density of a metallic material in the collimator walls and the at least one alignment element can also be achieved by means of an additive manufacturing technology and particularly advantageously in particular by means of a method of selective laser melting or laser sintering.

In a further advantageous embodiment of the proposed anti-scatter filter, the collimator element and the at least one alignment element can be produced by means of a method of selective laser melting or laser sintering of a metal powder.

In a variant, the collimator element and the at least one alignment element are produced using a method of selective laser melting or laser sintering of a metal powder. For example, in a method of selective laser melting (SLM) or laser sintering (SLS), powder layers of a metal powder can be used in the construction of the collimator walls and the at least one alignment element. Advantageously, the collimator element and the at least one alignment element can be constructed more quickly or cheaper materials can be used.

In a second aspect, the invention relates to an X-ray detector device comprising an X-ray detector and a proposed anti-scatter radiation filter in a stack arrangement along the first spatial direction, in particular the X-ray incidence direction.

The advantages of the proposed X-ray detector device essentially correspond to the advantages of the proposed anti-scatter filter. Features, advantages or alternative embodiments mentioned here can also be found the other claimed items are transferred and vice versa.

The X-ray detector can be a direct-converting or an indirect-converting X-ray detector.

The X-rays or the X-ray photons can be converted into electrical pulses in direct-converting X-ray detector devices using a suitable converter material. For example, CdTe, CZT, CdZnTeSe, CdTeSe, CdMnTe, InP, TlBr2, HgI2, GaAs or others can be used as converter material. The electrical pulses are evaluated by electronic circuits of an evaluation unit, for example in the form of an integrated circuit (Application Specific Integrated Circuit, ASIC). In counting X-ray detector devices, incident X-rays can be measured by counting the electrical pulses triggered by the absorption of X-ray photons in the converter material. The height of the electrical pulse is also usually proportional to the energy of the absorbed X-ray photon. This allows spectral information to be extracted by comparing the height of the electrical pulse with a threshold value.

The X-rays or the photons can be converted into light in indirect-converting X-ray detector devices using a suitable converter material and into electrical pulses using optically coupled photodiodes. Scintillators, such as GOS (Gd2O2S), CsJ, YGO or LuTAG, are often used as converter materials. The electrical signals generated are further processed via an evaluation unit having electronic circuits, read out and then forwarded to a computing unit.

The X-ray detector can comprise a matrix-like arrangement of a large number of pixel elements for a spatially resolved measurement of the incoming X-rays. The position of the anti-scatter filter, in particular the radiation channels and the collimator walls, can be aligned relative to the matrix-like arrangement of the plurality of pixel elements. For example, a collimator wall can be assigned to each pixel element or a group of pixel elements. For example, a collimator wall can be arranged between two adjacent pixel elements or between adjacent groups of pixel elements, for example macropixels. Preferably, an arrangement is such that as little as possible of a sensitive surface of a pixel element is covered by a collimator wall, so that a deterioration in the dose efficiency can be avoided. In embodiment variants, however, it is also conceivable that collimator walls are arranged entirely or partially above the X-ray sensitive detection surface of a pixel element.

Advantageously, image-effective scattered radiation striking the X-ray detector is reduced, thereby enabling improved image quality, while at the same time cost-efficient provision can be guaranteed.

In a further advantageous embodiment of the proposed X-ray detector device, the X-ray detector device can further comprise a holding element for fastening the anti-scatter filter in the stack arrangement, which has a corresponding alignment element to the at least one alignment element of the anti-scatter filter. The corresponding alignment element in the stack arrangement can rest positively against the at least one alignment element. The at least one corresponding alignment element can in particular have all the features and properties that have been described in relation to the at least one alignment element of the anti-scatter filter and vice versa. The corresponding alignment element can advantageously have at least two corresponding stop surfaces, which can be arranged in a form-fitting manner on the at least two stop surfaces of the at least one alignment element.

In a third aspect, the invention relates to a medical imaging device with a proposed X-ray detector device and an X-ray source in comparison to the X-ray detector device, which is designed to expose the X-ray detector device to X-rays along the first spatial direction, in particular the X-ray incidence direction.

The advantages of the proposed imaging device essentially correspond to the advantages of the proposed anti-scatter filter and/or the proposed X-ray detector device. Features, advantages or alternative embodiments mentioned here can also be transferred to the other claimed objects and vice versa.

To record an X-ray image data set, an examination object to be imaged can be placed between the X-ray source and the X-ray detector and irradiated using the X-ray source. In particular, the medical imaging device can be designed as a computer tomography system. But it can also, for example be designed as a C-arm X-ray device and/or Dyna-CT or as another X-ray-based imaging device.

In a fourth aspect, the invention relates to a computer tomography system, having a proposed medical imaging device. The computed tomography system may include a gantry with a rotor. The rotor can include an X-ray source and the detection unit. The detection unit can comprise at least one X-ray detector device according to the invention. The rotor can be mounted so that it can rotate about the axis of rotation. The examination object can be stored on a patient bed and can be moved through the gantry along an axis of rotation. The computer tomography system can have a computing unit to control the computer tomography system and to calculate cross-sectional images or volume images of the examination object.

• 1 eine schematische Darstellung einer vorteilhaften Ausführungsform einer Röntgendetektorvorrichtung umfassend einen Streustrahlenfilter aufweisend ein Kollimatorelement in Stapelanordnung mit einem Röntgendetektor,
• 2 eine schematische Darstellung einer vorteilhaften Ausführungsform eines Kollimatorelements eines Streustrahlenfilters,
• 3 eine schematische Darstellung einer vorteilhaften Ausführungsform eines medizinischen Bildgebungsgeräts.

Embodiments of the invention are shown in the drawings and are described in more detail below. In different figures, the same reference numbers are used for the same features. Show it:

• 1 a schematic representation of an advantageous embodiment of an X-ray detector device comprising an anti-scatter filter having a collimator element in a stack arrangement with an X-ray detector,
• 2 a schematic representation of an advantageous embodiment of a collimator element of an anti-scatter filter,
• 3 a schematic representation of an advantageous embodiment of a medical imaging device.

1 shows a schematic representation of an advantageous embodiment of an X-ray detector device comprising an X-ray detector 4 and an anti-scatter filter with a collimator element 2 and an alignment element AE1 in a stack arrangement along a first spatial direction (parallel to the x-axis in the figure) in a sectional view. In the illustration shown, the stacking direction and the direction of incidence of the rays run essentially parallel to the x-axis.

The scattered radiation filter is arranged in front of the X-ray detector 4 in the direction of a radiation incidence direction for the reduction of scattered radiation incident on the X-ray detector 4 during the exposure of the X-ray detector device to X-rays.

The X-ray detector 4 has a converter element 11 for converting incident X-rays into electrical signals. Furthermore, the converter element 11 is coupled via electrically conductive connections 15 to an evaluation unit 13, which is designed to further process the electrical signals from the converter element 11. The evaluation unit can also be coupled to a readout unit 17 for collecting and reading out the further processed signals or a substrate 17. The X-ray detector can in particular comprise a matrix-like arrangement of a large number of pixel elements for a spatially resolved measurement of the incoming X-rays. The X-ray detector 4 can be a direct-converting or an indirect-converting X-ray detector 4.

The anti-scatter filter for stacking along the first spatial direction, in particular an X-ray incidence direction, with the X-ray detector 4 has a collimator element 2 with a plurality of collimator walls 1, which are arranged essentially parallel to the first spatial direction, each collimator wall 1 of the plurality having a wall height h along the first spatial direction. The wall height of a respective collimator wall extends essentially along the first spatial direction. The wall height h can, for example, be in the range from 3 to 40 mm, preferably between 4 and 28 mm, more preferably the wall height is more than 8 mm.

The collimator walls 1 of the collimator element 2 are adjacent at least along a further spatial direction (parallel to the z-axis in the figure) and are arranged at a distance from one another in such a way that a radiation channel 3 is provided along the first spatial direction between two adjacent collimator walls 1. In a top view of the arrangement, this can then correspond to a grating structure or a slatted structure (in 2 shown). According to a preferred embodiment variant of the anti-scatter filter, collimator walls 1 are formed in a further direction perpendicular to the first spatial direction and the stacking direction, so that the collimator element 2 has a two-dimensional grid-shaped structure in a horizontal section transversely, in particular perpendicular, to the first spatial direction (in 2 shown). Such an anti-scatter filter can also be referred to as a 3D collimator. The collimator walls 1 and the radiation channels are aligned essentially parallel to the stacking direction, which can include that the collimator walls 1 and the radiation channels 3 formed thereby can also be aligned slightly inclined towards a focus point of an X-ray source 37 arranged for the exposure of the X-ray detector 4.

The collimator walls 1 preferably have a material that strongly absorbs X-rays, for example a metallic material. For example, the collimator walls have tungsten.

In the stack arrangement, the collimator element 2 has a radiation entry side 6 facing an X-ray source 37 for illuminating the X-ray detector 4 and facing away from the X-ray detector 4. Along the beam incidence direction of the beam entry side 6, the collimator element 2 correspondingly has a beam exit side 8 facing away from an X-ray source 37 for illuminating the X-ray detector 4 and facing the X-ray detector 4.

The anti-scatter filter can have further components in addition to the components shown here. For example, the anti-scatter filter includes a holding element for attaching the collimator element 2 to the X-ray detector 4 or to a module holder of an X-ray detector device. The collimator element 2 can also be attached directly to the converter element 11 in embodiment variants.

The X-ray detector device can further comprise a holding element for fastening the anti-scatter filter in the stack arrangement (not shown here), which has a corresponding alignment element to the at least one alignment element of the anti-scatter filter. The corresponding alignment element in the stack arrangement can rest positively against the at least one alignment element.

2 shows a schematic representation of an advantageous embodiment of a collimator element 2 of an anti-scatter filter. The collimator surface can be delimited by outer walls AW formed by collimator walls 1 arranged on the outside. Furthermore, at least one alignment element AE1 can be designed as a structural element, having at least two adjacent and non-parallel contact surfaces, adjacent to an outer side of at least one of the outer walls AW of the collimator element. Advantageously, an absorption capacity for X-rays of the at least one outer wall AW compared to the remaining collimator walls 1 cannot be reduced by the at least one alignment element AE1. The anti-scatter filter can in particular have a plurality of alignment elements AE1, AE2 and AE3, which in the present exemplary embodiment are at least partially the same and at least partially different. The alignment elements AE2 and AE3 can be designed, for example, as flanges. The contact surfaces of the at least one alignment element can be designed to align the anti-scatter filter in the first and/or at least one further spatial direction. Furthermore, the at least one alignment element can be designed as a survey and/or recess on an outside of the at least one outer wall of the collimator element. In particular, the alignment element AE1 can be designed as a stepped section on an outside of the at least one outer wall AW of the collimator element. The at least two contact surfaces can form the stepped section in an angled arrangement relative to one another. Advantageously, the alignment elements can each extend over an entire width of the at least one outer wall AW. In addition, the alignment elements AE1, AE2 and AE3 can each be arranged on an edge of the at least one outer wall AW of the collimator element.

Advantageously, the collimator element and the alignment elements AE1, AE2 and AE3 can be formed in one piece. In addition, the collimator element and the alignment elements AE1, AE2 and AE3 can be manufactured using an additive manufacturing technique. In particular, the collimator element and the alignment elements AE1, AE2 and AE3 can be manufactured using a method of selective laser melting or laser sintering of a metal powder.

3 shows an exemplary embodiment of a medical imaging device 32 with a detection unit 36 comprising at least one X-ray detector device according to the invention, comprising an X-ray detector 4 and an anti-scatter filter according to the invention with a collimator element 2, and an X-ray source 37 in comparison to the detection unit 36. The X-ray source 37 is designed, the detection unit 36 , and thus to expose the X-ray detector 4 to X-rays along the first spatial direction, in particular the X-ray incidence direction. The medical imaging device 32 shown is designed in particular as a computer tomography system. The computed tomography system includes a gantry 33 with a rotor 35. The rotor 35 includes an X-ray source 37 and the detection unit 36. The detection unit 36 includes at least one X-ray detector device. The rotor 35 is rotatably mounted about an axis of rotation 43. The examination object 39, here a patient, is stored on the patient bed 41 and can be moved along the axis of rotation 43 through the gantry 33. A computing unit 45 is used to control the computer tomography system and to calculate cross-sectional images or volume images of the examination object. An input device 47, for example a keyboard, and an output device 49, for example a screen and/or display, are connected to the computer unit 45 connected. The input device 47 can advantageously be integrated into the output device 49, for example in the case of an input display, in particular a resistive and/or capacitive one.

The schematic representations contained in the figures described do not represent any scale or size relationships.

Finally, it should be pointed out once again that the methods described above in detail and the devices shown are merely exemplary embodiments which can be modified in a variety of ways by a person skilled in the art without departing from the scope of the invention. Furthermore, the use of the indefinite articles “a” or “an” does not exclude the fact that the characteristics in question can be present multiple times. Likewise, the terms “unit” and “element” do not exclude that the components in question consist of several interacting sub-components, which may also be spatially distributed.

In the context of the present application, the expression “based on” can be understood in particular in the sense of the expression “using”. In particular, a formulation according to which a first feature is generated (alternatively: determined, determined, etc.) based on a second feature does not exclude that the first feature is generated (alternatively: determined, determined, etc.) based on a third feature can.

Claims (15)

Scattered radiation filter for an X-ray detector (4), wherein the anti-scatter filter has a collimator element (2) with a plurality of collimator walls (1) and at least one alignment element (AE1, AE2, AE3), wherein the collimator walls (1) are arranged in a grid-like manner, crossed relative to one another, in a collimator surface that is transverse to a first spatial direction, so that a plurality of radiation channels (3) extending elongated in the first spatial direction are formed between the crossed collimator walls (1), and wherein the collimator surface of is limited by external walls (AW) formed by collimator walls arranged on the outside, wherein the at least one alignment element (AE1, AE2, AE3) is designed as a structural element, having at least two adjacent and non-parallel contact surfaces, on an outside of at least one of the outer walls (AW) of the collimator element (2), wherein an absorption capacity for X-rays of the at least one outer wall (AW) is not reduced compared to the remaining collimator walls (1) by the alignment element (AE1, AE2, AE3), wherein the contact surfaces of the at least one alignment element (AE1, AE2, AE3) are designed to align the anti-scatter filter in the first and/or at least one further spatial direction. Anti-scatter filter Claim 1 , wherein the collimator walls (1) are additionally arranged substantially parallel to one another and parallel to the first spatial direction. Anti-scatter filter Claim 1 or 2 , wherein the at least one alignment element (AE1, AE2, AE3) is designed as a survey and / or recess on an outside of the at least one outer wall (AW) of the collimator element (2). Anti-scatter filter Claim 3 , wherein the at least one alignment element (AE1, AE2, AE3) is designed as a stepped section on an outside of the at least one outer wall (AW) of the collimator element (2), two of the at least two contact surfaces, which are arranged at an angle to one another, forming the stepped section form. Anti-scatter filter Claim 4 , wherein the at least one alignment element (AE1, AE2, AE3) extends over an entire width and / or height of the at least one outer wall (AW). Anti-scatter filter according to one of the preceding claims, comprising a plurality of alignment elements (AE1, AE2, AE3), which are at least partially designed in the same way. Anti-scatter filter according to one of the Claims 1 until 5 , having several alignment elements (AE1, AE2, AE3), which are at least partially designed differently. Anti-scatter filter according to one of the preceding claims, wherein the at least one alignment element (AE1, AE2, AE3) at least adjoins an edge of the at least one outer wall (AW) of the collimator element (2). Anti-scatter filter according to one of the preceding claims, wherein the collimator element (2) and the at least one alignment element (AE1, AE2, AE3) are formed in one piece. Anti-scatter filter Claim 9 , wherein the collimator element (2) and the at least one alignment element (AE1, AE2, AE3) are manufactured using an additive manufacturing technology. Anti-scatter filter Claim 10 , wherein the collimator element and the at least one alignment element (AE1, AE2, AE3) are produced by means of a method of selective laser melting or laser sintering of a metal powder. X-ray detector device comprising an X-ray detector (4) and an anti-scatter filter according to one of the preceding claims in a stack arrangement along the first spatial direction. X-ray detector device Claim 12 , further comprising a holding element for fastening the anti-scatter filter in the stack arrangement, which has a corresponding alignment element to the at least one alignment element (AE1, AE2, AE3) of the anti-scatter filter, wherein the corresponding alignment element in the stack arrangement is positively connected to the at least one alignment element (AE1, AE2 , AE3). Medical imaging device with an X-ray detector device Claim 12 or 13 and an X-ray source (37) in relation to the X-ray detector device, which is designed to expose the X-ray detector device to X-rays along the first spatial direction. Computed tomography system (33) comprising a medical imaging device Claim 14 .

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