Beam collimator

Abstract

The invention concerns a beam collimator for electromagnetic radiation, especially of X-ray spectrum, and / or ionizing radiation comprising: a plurality of beam-absorbing body portions stacked on top of one another with respect to a beam direction, each comprising a plurality of slits and a plurality of walls; wherein the slits respectively extend through the body portion substantially along a thickness direction of the body portion extending from beam input to beam output, the slits and walls alternating along a height direction of the body portion; and wherein the slits and walls of at least one first body portion are arranged relative to slits and walls of at least one further second body portion such that, in height direction, walls of the first body portion are entirely within respectively adjacent slits of the second body portion. The invention also concerns a beam collimator with walls and / or slits tapered along a width direction of a body portion thereof.

Description

Field of the Invention

[0001] The invention concerns beam collimators for electromagnetic radiation, particularly for X-ray radiation and / or ionizing radiation, especially a collimator for spatially fractionated radiation fields.Background of the Invention

[0002] Beam collimators for electromagnetic radiation, especially for collimating X-rays, and / or for ionizing radiation are known. Therein, especially for clinical purposes such as radiation therapy, so-called microbeams and minibeams are desirable. Such microbeams or minibeams refer to spatially fractioned radiation fields, or beams, with full width half maximum of their beam profiled being respectively roughly 10 - 100 µm (microbeams) or larger than 100 µm, especially up to 1000 µm (minibeams).

[0003] For example, "Establishment of Microbeam Radiation Therapy at a Small-Animal Irradiator" by Treibel et. al. in the International Journal of Radiation Oncology biology / physics (2020; DOI: https: / / doi.org / 10.1016 / i.iirobp.2020.09.039) shows such a collimator in its Fig.1. Therein, the collimator comprises three stacked body portions (plates) respectively with collimator slits. The slits are tilted to account for beam divergence. The radiation is absorbed by the body portions, and propagates through the slits to form multiple beams in correspondence with the number of slits, i.e. the number of slits of the final body portion with respect to a beam propagation direction.

[0004] However, such known collimators have multiple drawbacks.

[0005] For one, the number of beams corresponds to the number of their slits. Therefore, the common problem arises that to achieve more and / or narrower beams, the slits of the known collimators must be manufactured narrower, which is technically challenging and expensive especially under consideration of material properties of the collimator. Additionally, larger field sizes with longer slits and a larger number of slits is technically challenging and expensive.

[0006] . Therefore, if the radiation source produces an eccentric focal spot and / or the collimator is not placed precisely perpendicularly to the to a beam produced by the radiation source, total transmitted intensity or total yield, also referred to as total dose, and a peak-to-valley dose ratio (in the field of radiation therapy) in the beams are disadvantageously reduced.Summary

[0007] It is an object of the present invention to overcome these deficiencies. In particular, it is an object of the present invention to provide a beam collimator which provides more beams and / or narrower and / or longer beams and is easier to manufacture. Furthermore, it is an object of the present invention to provide a beam collimator which is suitable for a wide range of radiation sources and which can be positioned more freely with respect to the radiation source.

[0008] The solution of these objects is achieved by the subject matter of the independent claims. The dependent claims contain advantageous embodiments of the present invention.

[0009] In particular, the solution of these objects is achieved by the beam collimator according to claim 1. The beam collimator is for collimating beams of electromagnetic radiation, particularly of the x-ray spectrum, and / or ionizing radiation. The beam collimator (henceforth "collimator") comprises a plurality of beam-absorbing body portions stacked on top of one another with respect to a beam direction. Each of the body portions comprises a plurality of slits and a plurality of walls. The slits respectively extend through the body portion substantially along a thickness direction of the body portion, wherein the thickness direction extends from beam input to beam output (positive thickness direction). The slits and walls alternate along a height direction of the body portion. In other words, the height direction of the body portion is defined as the direction along which the slits and walls alternate. The slits and walls of at least one first body portion are arranged relative to slits and walls of at least one further second body portion such that, in height direction, walls of the first body portion are entirely within respectively adjacent slits of the second body portion.

[0010] In other words, when viewed along the thickness direction, i.e. following the substantial beam propagation direction (from input to output), cross-sections of walls of the second body portion are entirely visible through the slits of the first body portion.

[0011] Thereby, advantageously, much narrower effective slit widths are made possible without necessarily decreasing a real slit width. From another perspective, for a same effective slit width, the real slits can be manufactured larger, thereby decreasing manufacturing effort and costs for the collimator.

[0012] Preferably, each slit is defined as a space between two adjacent walls along the height direction.

[0013] Preferably, the body portions are opaque to the radiation (ionizing and / or electromagnetic), and the slits are substantially transparent to the radiation. In the preferable example of x-ray radiation, having a wavelength range between 10 nm and 0.1 pm, preferably around 2 pm (600 keV), especially up to 1 pm (1.2 MeV) or even up to 0.1 pm (12 MeV), the body portions comprise metal, for example tungsten and / or tungsten alloys and / or copper alloys. The slits are preferably air. In some embodiments, the slits are for example filled with or comprise a low-absorbing, especially transparent, material, such as for example carbon fiber, PMMA (Poly(methyl methacrylate)) or polycarbonate.

[0014] In preferable embodiments, a slit width along height direction of the second body portion is greater than a wall width along height direction of the first body portion. Thereby, advantageously, only light substantially non-parallel with the slits and walls is blocked by the collimator, thereby increasing

[0015] Advantageously, walls of the first body are arranged in height direction within slits of the second body portion such that a gap in height direction exists between walls of the first body portion and respectively two adjacent walls of the second body portion. Thereby, advantageously, two separate paths of beam propagation are formed, one on either side (in height direction) of a wall of the first body portion, i.e. through the respectively adjacent slit of the second body portion. Thereby, a number of effective slits is effectively increased as compared to a number of real slits of the collimator. Thus, the number of beams is advantageously increased, especially while maintaining low manufacturing effort and costs.

[0016] In some preferable embodiments, walls of the first body portion are arranged, in height direction, substantially in a middle of respectively adjacent slits of the second body portion. Herein, the term "substantially" refers to a discrepancy between middle points of the walls and respectively adjacent slits of roughly 10% or less of total slit width of that respectively adjacent slit owing to manufacturing errors or tolerances. Thereby, advantageously, beams propagating through the slit of the second body portion on either side (in height direction) of the respectively adjacent wall of the first body portion are substantially uniform.

[0017] In some embodiments, at least one third body portion stacked is stacked on top of the first body portion(s) and the second body portion(s). Thereby, advantageously, further collimation of the beam(s) is achieved in a simple manner.

[0018] Preferably, the second body portion is stacked directly on top of the first body portion and the third body portion is stacked directly on top of the second body portion. In other words, along beam propagation direction or positive thickness direction, the order is preferably first body portion, second body portion, third body portion.

[0019] Preferably, the slits and walls of the second portion are arranged relative to slits and walls of the at least one third body portion such that, in height direction, walls of the second body portion are entirely within respectively adjacent slits of the third body portion. In other words, preferably, the foregoing arrangement of slits and walls between the first body portion and the second body portion is repeated with respect to the second body portion and the third body portion. This has the advantage in that the beam(s) is further collimated while an advantageously high ratio of effective slits to real slits is upheld.

[0020] Preferably, slits of the first body portion(s) are collinear with slits of the third body portion(s).

[0021] Preferably, the first body portion and the third body portion are identical with regard to their structure. Thereby, the collimator can be easily manufactured. Furthermore, the collimator is thereby preferably reversible, i.e. in the manner that both sides with respect to the thickness direction thereof can act as beam input or beam output. In preferable implementations, such a collimator is combined with a non-divergent, i.e. parallel, radiation source.

[0022] In other advantageous embodiments, the slits of the first and third body portion(s) are collinear with one another, but not identical, i.e. the first body portion(s) and the third body portion(s) are non-identical. For example, spacing between the slits, i.e. wall widths, increases following along the beam direction between the body portions, especially in correspondence with a divergence of the beam.

[0023] In advantageous embodiments, slits of the first body portion have the same width along height direction as slits of the second body portion. Further preferably, slits of the first body portion have the same width along height direction as slits of the third body portion. Thereby, manufacturing of the collimator is simplified. In preferable embodiments, slit widths and / or wall widths of all body portions are substantially the same.

[0024] Preferably, the collimator comprises a plurality of first body portions and / or a plurality of second body portions and / or a plurality of third body portions. Therein, for example, the collimator preferably comprises multiple first body portions stacked on top of another and one or multiple second body portions stacked on top of another and stacked on top of the first body portions (for example, first, first, second or first, second, second or first, first, second, second, etc.). In other examples, the collimator comprises a plurality of first body portions and / or a plurality of second body portions arranged alternatingly on top of one another (for example, first, second, first or second, first, second, etc.). The same holds true with respect to the third body portion(s). Therein, the aforementioned relative positioning of slits and walls refers to adjacent first and second body portions and / or adjacent second and third body portions accordingly. Preferably, the aforementioned stacking possibilities refer to stacking along the beam direction, i.e. the thickness direction. In additional or alternative implementations, multiple first and / or second and / or third body portions are preferably stacked in height and / or width direction, thereby essentially forming multiple collimators side-by-side and / or on top of one another.

[0025] The present invention also concerns a beam collimator for electromagnetic radiation, especially of X-ray spectrum, and / or ionizing radiation wherein the beam collimator comprises at least one beam-absorbing body portion comprising a plurality of slits and a plurality of walls. Therein, the slits respectively extend through the body portion substantially along a thickness direction of the body portion extending from beam input to beam output. The slits and walls alternate along a height direction of the body portion perpendicular to the thickness direction and perpendicular to a width direction of the body portion. Furthermore, in the body portion, the slits and walls are slanted such that cross-sections, in a plane perpendicular to the thickness direction, of the walls and / or the slits are tapered along the width direction of the body portion.

[0026] In other words, when viewed from the front or back, i.e. perpendicularly to the substantial beam propagation direction onto beam input or output surfaces, the cross-sections of the slits and walls are tapered along the width direction. Thus, following along the width direction, these cross-sections have decreasing widths with respect to the height direction.

[0027] Thereby, the slits and / or walls of the body portion are advantageously oriented (slanted) to accommodate eccentric beams. Further, for concentric beams and / or eccentric asymmetric focal spots, the collimator is configured to accommodate a perspective on or a relative angle to the radiation source.

[0028] Preferably, the beam collimator with the aforementioned tapered cross-sections is combinable with any one of the embodiments and examples discussed above. Thereby, a collimator is achieved which simultaneously has advantageous slit widths and which can accommodate eccentric radiation sources or relative angles to concentric radiation sources.

[0029] Preferably, respective extension planes of a plurality of the slits are inclined such that their surface normal is slanted within a plane spanned by a height direction (height axis) and a width direction (width axis) of the body portion. Preferably, in other words, the slits (or corresponding walls) are slanted via a rotation axis which is parallel to the beam direction, i.e. the thickness direction. Further preferably, considering a divergent beam of rays producing essentially an eccentric cone of radiation, in any point on a slit's surface (or corresponding wall's surface), the surface normal at that point is perpendicular to the ray impinging on that point and is perpendicular to a line connecting that point with a center point of the radiation source (i.e. optical axis at source).

[0030] In some preferable embodiments, the walls and / or the slits of the body portion are additionally slanted such that their cross-sections, in a plane parallel to the thickness direction, are tapered along the thickness direction of the body portion. Thereby, the collimator is advantageously suited to accommodate beam divergence. In other words, herein, the slits (or corresponding walls) are slanted via a rotation axis which is perpendicular to the beam direction.

[0031] Further preferably, respective extension planes of a plurality of slits are inclined such that their surface normal is slanted within the plane spanned by the height direction (axis) and the width direction (width axis) and such that their surface normal is slanted within a plane spanned by the height direction (height axis) and the thickness direction (thickness axis). In other words, the slits (or corresponding walls) are slanted both to accommodate eccentric radiation sources as well as beam divergence, simultaneously.

[0032] Preferably, with respect to each of the slanting directions, the slits (or corresponding walls) are slanted such that, along the height direction, a top half of the slits (or corresponding walls) are slanted in the opposite direction with respect to a bottom half of the slits (or corresponding walls) such that the top half is slanted towards the bottom half and vice versa.

[0033] Preferably, a middle slit between the halves is not slanted. Therein, with a middle slit, the top half corresponds to the total number of slits divided by two (exact half) and minus one (to accommodate middle slit), and the same holds true for the bottom half.

[0034] Preferably, in this collimator comprising the tapered cross-sections, as an exemplary combination with the foregoing collimators, a plurality of beam-absorbing body portions are stacked on top of one another with respect to a beam direction, each comprising the plurality of slits and the plurality of walls. Therein, the slits and walls of at least one first body portion are arranged relative to slits and walls of at least one further second body portion such that, in height direction, walls of the first body portion are entirely within respectively adjacent slits of the second body portion.

[0035] Preferably, slits and walls of one of the body portions are slanted in the same manner as slits and walls of at least one other, especially all other, of the body portions. Thereby, manufacturing is made more efficient, especially since multiple body portions, especially all body portions, can be manufactured in the same manner.

[0036] The present invention furthermore concerns a radiation device comprising the beam collimator according to any or multiple of the above examples and a radiation source, particularly an x-ray radiation source. One example of a preferred x-ray radiation source is a line-focus x-ray tube.

[0037] The present invention also concerns the use of the collimator and / or the radiation device above for treatment in microbeam or minibeam radiation therapy, especially for pre-clinical and / or veterinary and / or intra-operative radiation therapy, especially in medicine and / or for the treatment of cancer and / or concerns the use of the collimator and / or the radiation device above for imaging.

[0038] The foregoing described preferable embodiments and configurations may be combined.

[0039] Further details, advantages, and features of the preferred embodiments of the present invention are described in detail with reference to the figures. Therein:Brief Description of the Drawings

[0040] Fig. 1 shows a perspective view of a beam collimator according to a first embodiment of the present invention; Fig. 2 shows another perspective view and magnified cross-sections of the beam collimator of fig. 1; Fig. 3 shows a plurality of perspective views on a beam collimator according to a second embodiment of the present invention; and Fig. 4 shows a perspective view on the beam collimator of fig. 3 together with a radiation source. Description of the Embodiments

[0041] A first embodiment of the present invention will be described with reference to figs. 1 and 2, wherein fig. 1 shows a perspective view of a beam collimator 10 and fig. 2 shows a perspective view and magnified cross sections of the beam collimator 10 of the first embodiment.

[0042] First, the overall structure of the beam collimator 10 (henceforth "collimator" 10) will be explained in view of fig. 1.

[0043] The collimator 10 is for collimating electromagnetic radiation (100; see figs. 2 and 4 to this regard) and / or ionizing radiation. In the present embodiment, although not principally limited thereto, the collimator 10 is configured to collimate x-ray radiation.

[0044] The collimator 10 comprises a plurality of, in the present embodiment three, beam-absorbing body portions 1, 2, 3, which are stacked on top of one another. A stacking direction thereof is parallel to a beam direction (see figs. 2 and 4), wherein the general beam direction essentially corresponds to a thickness direction 6 of the collimator 10.

[0045] In the present embodiment, the three body portions 1, 2, 3, are separate from one another and attached to one another. In other words, in the present embodiment, the three body portions 1, 2, 3, are not formed integrally with one another, especially not formed monolithically with one another. In other examples, one or more of the body portions 1, 2, 3 can be formed integral, and especially monolithically, with one another.

[0046] Furthermore, each of the body portions 1, 2, 3, as especially shown in fig. 2, comprises a plurality of slits 4 and a plurality of walls 5. Therein, the slits 4 are respectively defined as substantially transparent spaces, filled with air and / or transparent material, between two adjacent walls 5. The slits 4 and walls 5 alternate along a height direction 7 of the respective body portion 1, 2, 3 or of the collimator 10, wherein the height direction 7 is perpendicular to the thickness direction 6.

[0047] Herein, the collimator 10 comprises the three body portions 1, 2, 3, namely a first body portion 1, a second body portion 2, and a third body portion 3. In some examples and modifications to the embodiment, the collimator 10 can comprise only two body portions 1, 2, i.e. a first body portion 1 and a second body portion 2.

[0048] Furthermore, as will also be clearer from the following description of fig. 2, as can be taken from fig. 1, the second body portion 2 is shifted in height direction 7 with respect to the first body portion 1 and the third body portion 3, between which it is sandwiched. It should be noted that the shown shift is not necessary, as the outer surfaces and dimensions of the body portions 1, 2, 3 and thus the collimator 10 can be adapted to provide flush outer surfaces.

[0049] Now, with respect to fig. 2, the slits 4 and walls 5 of the collimator 10 will be explained in more detail.

[0050] Herein, fig. 2a shows a front view on the collimator 10 shown in fig. 1, especially on the first body portion 1. Fig. 2b shows a cross-section of the collimator 10 including all three body portions 1, 2, 3, and fig. 2c shows a magnification of fig. 2b for easier understanding. In figs. 2b and 2c, the arrangement of slits 4 and walls 5 along the thickness direction 6 is visible.

[0051] As can be taken from figs. 2b and 2c, the slits 4 and walls 5 extend through the respective body portion 1, 2, 3 along the thickness direction 6, and especially entirely through the respective body portion 1, 2, 3. In fig. 2c, a beam of radiation 100 is shown, wherein the arrow direction propagates from beam input to beam output side of the collimator 10. For the sake of easier understanding, presently, the beam is input first into the first body portion 1, enters the second body portion 2, and enters and leaves the third body portion 3 as collimated output.

[0052] Herein, the slits 4 and walls 5 of the first body portion 1 are arranged relative to slits 4 and walls 5 of the second body portion 2 such that, in height direction 7, walls 5 of the first body portion 1 are entirely within respectively adjacent slits 4 of the second body portion 2. In other words, as shown especially in figs. 2b and 2c, following along the thickness direction 6, the walls 5 of the first body portion 1 overlap with the slits 4 of the second body portion 2 and vice versa.

[0053] Herein, a slit width 9 along the height direction 7 of the slits 4 of the second body portion 2 is greater than a wall width 11 along the height direction 7 of the first body portion 1. In other words, the slits 4 of the second body portion 2 are wider than the walls 5 of the first body portion 1.

[0054] Furthermore, walls 5 of the first body portion 1 are arranged, in height direction 7, within the slits 4 of the second body portion 2 such that a gap 12 in height direction 7 exists between walls 5 of the first body portion 1 and respectively two adjacent walls 5 of the second body portion 2. Thereby, as can be taken from fig. 2c especially, radiation beams can traverse on both sides, in height direction 7, of each wall 5 of the first body portion 1 into the adjacent slit 4 of the second body portion 2.

[0055] In the present embodiment comprising the three body portions 1, 2, 3, the slits 4 and walls 5 of the second body portion 2 are also arranged relative to slits 4 and walls 5 of the third body portion 3 such that, in height direction 7, walls 5 of the second body portion 2 are entirely within respectively adjacent slits 4 of the third body portion 3. In other words, the foregoing described relative arrangement between the first body portion 1 and the second body portion 2 is essentially repeated for the second body portion 2 and the third body portion 3.

[0056] Furthermore, the slits 4 of the first body portion 1 are collinear with slits 4 of the third body portion 3. Herein, preferably, the wall width 11, i.e. the spacing between slits 4, of the third body portion 3 is greater than that of the first body portion 1. In particular, these dimensions preferably diverge along the thickness direction 6 corresponding to a divergence of the beam. In alternative embodiments, the first body portion 1 and the third body portion 3 are preferably identical and are arranged parallel and at a same height (along height direction 7), which is preferably suitable for non-divergent beams of radiation.

[0057] Preferably, the slits 4 of the first body portion 1 have the same width 9 along height direction 7 as slits 4 of the second body portion 2, and have the same width 9 along height direction 7 as the slits 4 of the third body portion 3. In other words, in preferable embodiments, the slits 4 and walls 5 of each of the body portions 1, 2, 3, may be essentially arranged in the same manner, with the entire second body portion 2 being shifted relative to the first body portion 1 and the third body portion 3.

[0058] Herein, the second body portion 2 is shifted in height direction 7 with respect to the first body portion 1 and the third body portion 3, but alternatively or in addition thereto the slits 4 and walls 5 of the second body portion 2 may be shifted with respect to the first body portion 1 and the third body portion 3. Furthermore, due to the embodiment concerning relative arrangements, it is to be understood that the first body portion 1 and the third body portion 3 may be relatively shifted (their slits / walls and / or the entire body portion 1, 3) with respect to the second body portion 2.

[0059] Furthermore, in the present embodiment, walls 5 of the first body portion 1 are arranged, in height direction 7, substantially in a middle of respectively adjacent slits 4 of the second body portion 2. Thereby, advantageously, beams 100 shown in fig. 2c propagating through the slit 4 of the second body portion 2 on either side (in height direction 7) of the respectively adjacent wall 5 of the first body portion 1 are substantially uniform.

[0060] In the present embodiment, as shown especially in fig. 2b, the slits 4 and walls 5 of all body portions 1, 2, 3 are slanted so as to diverge, i.e. spread apart, along the beam direction, i.e. along the thickness direction 6 from input to output. In other words, when viewed along a plane parallel to the thickness direction 6, i.e. the plane of the cross-section shown in fig. 2c formed by the thickness direction 6 and the height direction 7, cross-sections of the slits 4 and / or walls 5 of the body portions 1, 2, 3 are tapered, here from output to input (with tapering meaning converging). This has the advantage in that divergence of the radiation source 101 (compare fig. 4) can be accommodated by the slits 4 and walls 5, i.e. the total radiation collimated is increased.

[0061] As demonstrated in fig. 2c, the collimator 10 of the present embodiment thereby achieves at least twice the amount of beams output from the collimator 10 with regard to a number of slits 4 of each body portion 1, 2, 3. Therefore, without increasing manufacturing costs, the number of effective slits is at least doubled with respect to the number of real slits 4 (i.e. the number actually formed in the respective body portion 1, 2, 3). Thereby also, for the same amount of beams, for example, the number of real slits 4 can be reduced by half, which makes it easier to manufacture the collimator 10. Furthermore, the width 11 of walls 5 can be increased, thereby increasing a structural integrity of the collimator 10 as well as making manufacturing easier and cost-effective. Thicker walls 5 of the collimator 10 also has the benefit of providing more absorption of the radiation, thereby increasing a peak-to-valley ratio of collimated radiation output by the collimator 10.

[0062] Now, in view of figs. 3 and 4, a second embodiment of the present invention will be explained, wherein fig. 3 shows multiple perspective views of a collimator 10 according to the second embodiment, and fig. 4 shows a perspective view of the collimator 10 of fig. 3 along with a radiation source 101. In particular, fig. 4 demonstrates a more realistic beam 100 as compared to fig. 2c.

[0063] In fig. 3, for easier understanding, fig. 3a shows a perspective view on the collimator 10, whereas figs. 3b and 3c each show transparent views thereof to demonstrate the arrangement of slits 4 and walls 5 therein. Further, for easier understanding, fig. 3c is rotated around the height direction 7 (as rotation axis) versus figs. 3a and 3b.

[0064] In the present embodiment, especially in addition to the foregoing discussion of the first embodiment, the collimator 10 comprises in each body portion 1, 2, 3, slanted slits 4 and walls 5. Herein, the slits 4 and walls 5 are slanted such that cross-sections, in a plane perpendicular to the thickness direction 6, for example the substantially shown plane in fig. 3a formed by the height direction 7 and the width direction 8, of the walls 5 and / or the slits 4 of the body portions 1, 2, 3 are tapered along the width direction 8 of the body portions 1, 2, 3.

[0065] In other words, as shown in fig. 3, the slits 4 and walls 5 are slanted so as to converge when following the width direction 8.

[0066] In the present sense, cross-sections of "slits 4 and / or walls 5" being tapered refers to the fact that if the widths of the slits 4 are tapered, then the corresponding widths of the walls 5 between the slits 4 would increase, and vice versa.

[0067] In fig. 3b, a surface normal 13 of a slit 4 is shown. As can be taken therefrom, the surface normal 13 is slanted within a plane spanned by the height direction 7 (a height axis) and the width direction 8 (a width axis) of the body portions 1, 2, 3.

[0068] The foregoing described slanting shown in fig. 3 is, in the present embodiment, additional to the slanting shown in and explained with view on fig. 2b, as is especially shown in fig. 3c. Furthermore, as visible in fig. 3c, the relative arrangement of slits 4 and walls 5 of the second body portion 2 relative to the first body portion 1 and the third body portion 3 is also achieved in this exemplary second embodiment.

[0069] As demonstrated in fig. 2c and fig. 3, each of the foregoing described slanting directions are preferably carried out such that, with respect to height direction 7, top and bottom slits 4 are slanted towards slits 4 in a middle, with respect to height direction 7, of the body portions 1, 2, 3. Preferably, at least one or multiple of such middle slits 4 in height direction 7 are not slanted, i.e. are parallel to the plane defined by the thickness direction 6 and the width direction 8 (respectively thickness axis and width axis). In the present figures, the directions 6, 7, 8 are parallel to respective axes of the body portions 1, 2, 3 or the collimator 10.

[0070] By providing the foregoing described slanting of fig. 3, as shown in fig. 4, the collimator 10 can accommodate radiation from the radiation source 101 with an eccentric focus, or with a relative angle between the collimator 10 and the radiation source 101. Thereby, the collimator 10 of the present embodiments achieves optimal throughput and intensity of radiation 100, particularly x-ray radiation. In fig. 4, a radiation source 101 with a line focus, such as a line-focus x-ray tube, is shown.

[0071] The collimator 10 of the present embodiments preferably achieves planar 20 - 500 µm wide beams of x-ray radiation.

[0072] In addition to the foregoing written explanations, it is explicitly referred to figures 1 to 4, wherein the figures in detail show configuration examples of the invention.List of Reference Numerals

[0073] 1First body portion 2Second body portion 3Third body portion 4slits 5walls 6thickness direction / thickness axis 7height direction / height axis 8width direction / width axis 9slit width 10beam collimator 11wall width 12gap 13surface normal 100radiation / beam 101radiation source

Claims

1. Beam collimator (10) for electromagnetic radiation (100), especially of x-ray spectrum, and / or ionizing radiation comprising: a plurality of beam-absorbing body portions (1, 2, 3) stacked on top of one another with respect to a beam direction, each comprising a plurality of slits (4) and a plurality of walls (5); wherein the slits (4) respectively extend through the body portion (1, 2, 3) substantially along a thickness direction (6) of the body portion (1, 2, 3) extending from beam input to beam output, the slits (4) and walls (5) alternating along a height direction (7) of the body portion (1, 2, 3); and wherein the slits (4) and walls (5) of at least one first body portion (1) are arranged relative to slits (4) and walls (5) of at least one further second body portion (2) such that, in height direction (7), walls (5) of the first body portion (1) are entirely within respectively adjacent slits (4) of the second body portion (2).

2. Beam collimator (10) according to claim 1, wherein a slit width (9) along height direction (7) of the second body portion (2) is greater than a wall width (11) along height direction (7) of the first body portion (1).

3. Beam collimator (10) according to any one of the foregoing claims, wherein walls (5) of the first body portion (1) are arranged in height direction (7) within the slits (4) of the second body portion (2) such that a gap (12) in height direction (7) exists between walls (5) of the first body portion (1) and respectively two adjacent walls (5) of the second body portion (2).

4. Beam collimator (10) according to any one of the foregoing claims, wherein walls (5) of the first body portion (1) are arranged, in height direction (7), substantially in a middle of respectively adjacent slits (4) of the second body portion (2).

5. Beam collimator (10) according to any one of the foregoing claims, wherein at least one third body portion (3) is stacked on top of the first body portion (1) and the second body portion (2).

6. Beam collimator (10) according to claim 5, wherein the slits (4) and walls (5) of the second body portion (2) are arranged relative to slits (4) and walls (5) of the at least one third body portion (3) such that, in height direction (7), walls (5) of the second body portion (2) are entirely within respectively adjacent slits (4) of the third body portion (3).

7. Beam collimator (10) according to claims 5 or 6, wherein slits (4) of the first body portion (1) are collinear with slits (4) of the third body portion (3).

8. Beam collimator (10) according to any one of the foregoing claims, wherein slits (4) of the first body portion (1) have the same width (9) along height direction (7) as slits (4) of the second body portion (2), and especially have the same width (9) along height direction (7) as slits (4) of the third body portion (3) of claims 5 to 7.

9. Beam collimator (10) for electromagnetic radiation (100), especially of x-ray spectrum, and / or ionizing radiation comprising: at least one beam-absorbing body portion (1, 2, 3) comprising a plurality of slits (4) and a plurality of walls (5); wherein the slits (4) respectively extend through the body portion (1, 2, 3) substantially along a thickness direction (6) of the body portion (1, 2, 3) extending from beam input to beam output, the slits (4) and walls (5) alternating along a height direction (7) of the body portion (1, 2, 3) perpendicular to the thickness direction (6) and perpendicular to a width direction (8) of the body portion (1, 2, 3); and wherein in at least one of the body portion(s) (1, 2, 3), the slits (4) and walls (5) are slanted such that cross-sections, in a plane perpendicular to the thickness direction (6), of the walls (5) and / or the slits (4) are tapered along the width direction (8) of the body portion (1, 2, 3).

10. Beam collimator (10) according to claim 9, wherein respective extension planes of a plurality of the slits (4) are inclined such that their surface normal (13) is slanted within a plane spanned by the height direction (7) and the width direction (8) of the body portion (1, 2, 3).

11. Beam collimator (10) according to claim 9 or claim 10, wherein the walls (4) and / or the slits (5) of the body portion (1, 2, 3) are additionally slanted such that their cross-sections, in a plane parallel to the thickness direction (6), are tapered along the thickness direction (6) of the body portion (1, 2, 3) .

12. Beam collimator (10) according to claim 11 with claim 10, wherein respective extension planes of a plurality of slits (4) are inclined such that their surface normal (13) is slanted within the plane spanned by the height direction (7) and the width direction (8) and such that their surface normal (13) is slanted within a plane spanned by the height direction (7) and the thickness direction (6).

13. Beam collimator (10) according to any one of claims 9 to 12, wherein a plurality of beam-absorbing body portions (1, 2, 3) are stacked on top of one another with respect to a beam direction, each comprising the plurality of slits (4) and the plurality of walls (5), wherein the slits (4) and walls (5) of at least one first body portion (1) are arranged relative to slits (4) and walls (5) of at least one further second body portion (2) such that, in height direction (7), walls (5) of the first body portion (1) are entirely within respectively adjacent slits (4) of the second body portion (2).

14. Beam collimator (10) according to claim 13, wherein slits (4) and walls (5) of one of the body portions (1) are slanted in the same manner as slits (4) and walls (5) of at least one other, especially all other, of the body portions (2, 3).

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