X-ray rotating anode with reduced out-of-focus X-ray radiation

Abstract

The invention relates to an X-ray rotating anode, an X-ray tube and an X-ray radiator. The X-ray rotating anode according to the invention has:-a support body made of molybdenum and / or a molybdenum alloy,-a first focal point strip formed on the support body; the invention relates to a laser device comprising a substrate, a first focal zone formed on the substrate, a second focal zone formed on the substrate, the first focal zone and / or the second focal zone comprising tungsten and / or rhenium, characterized in that the first focal zone and / or the second focal zone are / is formed on the substrate by means of a VPS coating method, and the first focus zone and the second focus zone are spaced apart from each other by an intermediate section in the carrier between the first focus zone and the second focus zone.

Description

Technical Field

[0001] The present invention relates to an X-ray rotating anode, an X-ray tube and an X-ray radiator. Background Art

[0002] In an X-ray tube, electrons are accelerated from a cathode toward an anode to generate X-ray radiation in a focal spot. The anode is typically rotatably mounted to distribute the heat introduced into the anode by the electron interactions along the focal spot. Using such rotating X-ray anodes, a high dose rate can generally be achieved in the generated primary X-ray radiation.

[0003] Extrafocal X-ray radiation is generated, in particular, outside the focal spot or focal zone, in particular in the surroundings of the focal spot or focal zone, by scattered electrons and / or reflected at the anode. Extrafocal X-ray radiation has, in particular, spectral characteristics similar to those of the primary X-ray radiation. Consequently, extrafocal X-ray radiation can result in additional patient dose and / or image artifacts, depending in particular on the collimation of the X-ray radiation. Typical image artifacts are shadow casting, which reduces image quality. Conventionally, extrafocal X-ray radiation can be reduced by additional filters, collimation, and / or by geometric adjustments. Summary of the Invention

[0004] The object underlying the present invention is to provide an X-ray rotating anode, an X-ray tube and an X-ray radiator with reduced out-of-focus X-ray radiation.

[0005] The object is achieved by an X-ray rotating anode, an X-ray tube, and an X-ray radiator. Advantageous embodiments are described in the following description.

[0006] Regardless of the grammatical gender of a particular term, persons with male or female gender identities are included.

[0007] The X-ray rotating anode according to the present invention has:

[0008] - a carrier body consisting of molybdenum and / or a molybdenum alloy,

[0009] a first focal zone formed on the carrier,

[0010] a second focal zone formed on the carrier,

[0011] - wherein the first focal zone and / or the second focal zone comprises tungsten and / or rhenium,

[0012] It is characterized by:

[0013] The first focal zone and / or the second focal zone are formed on the carrier by means of a VPS coating method, and

[0014] The first focal zone and the second focal zone are spaced apart from one another by an intermediate section between the first focal zone and the second focal zone in the carrier.

[0015] According to one embodiment, the middle section comprises a connecting plate which is delimited on one side by a first focal zone and on the other side by a second focal zone.

[0016] According to one embodiment, the intermediate section comprises a well which is delimited on one side by a first focal zone and on the other side by a second focal zone.

[0017] According to one embodiment, the underside of the first focal zone and the underside of the second focal zone are parallel to the surface plane of the intermediate section.

[0018] According to one embodiment, the surface of the carrier has a first groove and a second groove, wherein the first focal zone is formed in the first groove and the second focal zone is formed in the second groove.

[0019] According to one embodiment, the first focal zone, the middle section and the second focal zone are designed to be plane-parallel to one another.

[0020] According to one embodiment, the first focal zone, the middle section, and the second focal zone are designed in a stepped manner relative to one another.

[0021] According to one embodiment, the first focal zone and the second focal zone are designed in a stepped manner with respect to the sections of the carrier plate that are connected to the first focal zone and the second focal zone.

[0022] According to one embodiment, the first focal zone and the second focal zone are designed plane-parallel with respect to a section of the carrier plate connected to the first focal zone and the second focal zone.

[0023] According to one embodiment, the first focal zone and the second focal zone are formed in a common production step on the carrier so as to be continuous and are subsequently separated by forming an intermediate section.

[0024] The X-ray tube according to the present invention has:

[0025] - an evacuated housing having an X-ray exit window,

[0026] - electron emitters, and

[0027] -X-ray rotating anode,

[0028] - wherein the electron emitter and the X-ray rotating anode are arranged in a vacuum housing.

[0029] According to one embodiment, the X-ray exit window is configured to filter X-rays generated in the middle section.

[0030] According to one embodiment, the X-ray exit window comprises beryllium and / or titanium and / or aluminum for filtering.

[0031] The X-ray radiator according to the invention has:

[0032] -X-ray tube, and

[0033] A filter unit for filtering the X-rays generated in the middle section, said filter unit being arranged outside the evacuated housing.

[0034] According to one embodiment, the filter unit comprises aluminum and / or titanium. In principle, the filter unit can also comprise beryllium.

[0035] By separating the first and second focal zones by an intermediate section in the carrier, a molybdenum-free region of the carrier is advantageously created between the focal zones. Scattered or reflected electrons incident on this free region advantageously produce a radiation spectrum that is shifted compared to the radiation spectrum of the focal zones. The present invention therefore has the advantage that the energy shift between the two radiation spectra allows for significantly simpler reduction of out-of-focus X-ray radiation. This, in particular, improves image quality and / or reduces the number of image artifacts, particularly those negatively impacted by shadow casting from out-of-focus X-ray radiation.

[0036] The reduction of out-of-focus X-ray radiation can be achieved, for example, with the aid of a filter that is part of and / or additionally provided to the X-ray exit window of an X-ray tube having a rotating X-ray anode. The filter can be, in particular, a beryllium filter, a titanium filter, and / or an aluminum filter. Medical X-ray tubes, in particular, are often equipped with aluminum filters, eliminating the need for additional effort. BRIEF DESCRIPTION OF THE DRAWINGS

[0037] In the following, the present invention is described and explained in detail based on the embodiments shown in the drawings. In principle, in the following description of the drawings, structures and units that remain essentially the same are named with the same reference numerals as when the corresponding structure or unit first appears.

[0038] The accompanying drawings show:

[0039] Figure 1 The X-ray rotating anode according to the present invention is shown,

[0040] Figure 2 The X-ray rotating anode in the first embodiment is shown.

[0041] Figure 3 The X-ray rotating anode in the second embodiment is shown.

[0042] Figure 4 The X-ray rotating anode in the third embodiment is shown.

[0043] Figure 5 The X-ray rotating anode in the fourth embodiment is shown.

[0044] Figure 6 The X-ray rotating anode in the fifth embodiment is shown.

[0045] Figure 7 shows an X-ray tube according to the present invention, and

[0046] Figure 8 An X-ray radiator according to the invention is shown. DETAILED DESCRIPTION

[0047] Figure 1 The X-ray rotating anode 10 according to the invention is shown in an overview cross-sectional illustration.

[0048] The X-ray rotating anode 10 has a carrier body 11 made of molybdenum, preferably a molybdenum alloy, in particular TZM. The X-ray rotating anode 10 also has a first focal zone 12 formed on the carrier body 11 and a second focal zone 13 formed on the carrier body 11. The first focal zone 12 and the second focal zone 13 include tungsten, preferably in combination with rhenium.

[0049] The first focal zone 12 and preferably the second focal zone 13 are formed on the carrier 11 by means of a VPS coating method. The first focal zone 12 and the second focal zone 13 are spaced apart from one another by a central section 14 in the carrier 11 between the first focal zone 12 and the second focal zone 13 .

[0050] The first focal zone 12 and the second focal zone 13 are preferably formed in separate manufacturing steps without connection on the carrier 11. In this case, the middle section 14 can be produced, for example, by performing a VPS coating process spaced apart and / or masking the middle section 14.

[0051] Alternatively, the first focal zone 12 and the second focal zone 13 can be formed in a common manufacturing step on the carrier 11 in a continuous manner and subsequently separated by forming the intermediate section 14. Forming the intermediate section 14 can include removing at least the VPS coating. Removal can be performed, for example, by unscrewing and / or laser methods.

[0052] In particular, the X-ray rotating anode 10 is further ground after the first focal zone 12 and the second focal zone 13 are formed.

[0053] The carrier 11 is configured in particular for cooling the first focal zone 12 and / or the second focal zone 13. The X-ray rotating anode 10 is designed rotationally symmetrically and is typically mounted so as to be rotatable about an axis of rotation R. Therefore, in particular, the first focal zone 12 and / or the second focal zone 13 are also designed rotationally symmetrically, preferably in the form of an annulus.

[0054] The middle section 14 has in particular no VPS coating. Advantageously, the middle section comprises only the material of the carrier 11. The middle section 14 has in particular the same material composition as the carrier 11.

[0055] The X-ray radiation generated by means of the rotating X-ray anode 10 is, in particular, useful X-ray radiation and / or is suitable for imaging and / or therapeutic applications. Among imaging applications, a distinction is made between medical and non-medical applications. Medical applications are, in particular, computed tomography, mammography, and / or angiography. Non-medical applications are, in particular, material inspection, security inspection, and / or customs inspection.

[0056] The X-ray radiation generated in the middle section 14 is in particular extrafocal X-ray radiation which can be reduced according to the invention.

[0057] The schematic cross-sectional view along the axis of rotation R also shows a section enclosed by a dashed line, which is located at Figures 2 to 6 Due to the rotational symmetry of the X-ray rotating anode 10 , the first focal zone 12 , the second focal zone 13 and the middle section 14 are preferably designed identically in their respective embodiments, regardless of angle, as shown in the detail.

[0058] Figure 2 A detailed view of an X-ray rotating anode 10 according to the present invention is shown in a first embodiment.

[0059] The first embodiment is characterized in that the middle section 14 comprises a connecting plate 15, which is bounded on one side by the first focal zone 12 and on the other side by the second focal zone 13. The connecting plate 15 is in particular formed as part of the carrier 11. The connecting plate 15 is in particular composed of the same material as the carrier 11. The height of the connecting plate 15 is preferably at least the thickness of the first focal zone 12 and the thickness of the second focal zone 13.

[0060] The first focal zone 12, the middle section 14, and the second focal zone 13 are parallel to each other. The first focal zone 12 and the second focal zone 13 are designed in a stepped manner with respect to the sections of the carrier plate 11 connected to the first focal zone 12 and the second focal zone 13. The sections connected to the first focal zone 12 and the second focal zone 13 particularly surround the first focal zone 12, the second focal zone 13, and the middle section 14 located therebetween.

[0061] Figure 3 A detailed view of an X-ray rotating anode 10 according to the present invention is shown in a second embodiment.

[0062] The second embodiment is characterized in that the middle section 14 includes a shaft 16, which is bounded on one side by the first focal zone 12 and on the other side by the second focal zone 13. The bottom of the shaft 16 is deeper than the bottom of the first focal zone 12 and the bottom of the second focal zone 13. The shaft 16 can be formed, in particular, by means of a subtractive method. The subtractive method can, in particular, be a screwing and / or laser method. The depth of the shaft 16 is advantageously configured so that the X-rays generated in the middle section 14 decay within the shaft 16, for example at the shaft wall.

[0063] The first focal zone 12, the middle section 14 and the second focal zone 13 are stepped relative to each other. The first focal zone 12 and the second focal zone 13 are stepped relative to the sections of the carrier plate 11 that connect to them.

[0064] Figure 4 A detailed view of an X-ray rotating anode 10 according to the present invention is shown in a third embodiment.

[0065] The third embodiment is characterized in that the underside of the first focal zone 12 and the underside of the second focal zone 13 are plane-parallel to the surface of the middle section 14. In this case, the surface of the middle section 14 corresponds in particular substantially to the original surface of the carrier 11 and therefore in particular has no connecting webs 15 or no wells 16.

[0066] The first focal zone 12, the middle section 14 and the second focal zone 13 are stepped relative to each other. The first focal zone 12 and the second focal zone 13 are stepped relative to the sections of the carrier plate 11 that connect to them.

[0067] Figure 5 A detailed view of an X-ray rotating anode 10 according to the present invention is shown in a fourth embodiment.

[0068] The fourth embodiment is characterized in that the surface of the carrier 11 has a first groove 17 and a second groove 18. The first focal zone 12 is formed in the first groove 17, and the second focal zone 13 is formed in the second groove 18. The first groove 17 and the second groove 18 are filled, in particular, by means of a VPS coating method to form the first focal zone 12 and the second focal zone 13.

[0069] Alternatively, the surface of the carrier 11 can have a wide groove, wherein the first focal band 12 is formed in the first groove 17 and the second focal band 13 is formed in the second groove 18, wherein the intermediate section 14 includes a connecting plate 15, which is limited on one side by the first focal band 12 and on the other side by the second focal band 13 and is arranged between the first focal band 12 and the second focal band 13 in the wide groove.

[0070] The first focal zone 12, the middle section 14 and the second focal zone 13 are parallel to one another. The first and second focal zones 12, 13 are parallel to one another with respect to the sections of the carrier plate 11 that connect them.

[0071] Figure 6 A detailed view of an X-ray rotating anode 10 according to the present invention is shown in a fifth embodiment.

[0072] The fifth embodiment is characterized in that the intermediate section 14 comprises a shaft 16, which is bounded on one side by the first focal zone 12 and on the other side by the second focal zone 13. The bottom of the shaft 16 is formed deeper than the lower side of the first focal zone 12 and the lower side of the second focal zone 13. The first focal zone 12 and the second focal zone 13 are formed within a wide groove or first and second groove in the surface of the carrier 11.

[0073] The first focal zone 12, the middle section 14 and the second focal zone 13 are designed in a stepped manner relative to each other. The first and second focal zones 12, 13 are designed plane-parallel with respect to the sections of the carrier plate 11 adjoining them.

[0074] Figure 7 A longitudinal section along the axis of rotation R of an X-ray tube 20 according to the invention is shown.

[0075] The X-ray tube 20 includes an evacuated housing 21 having an X-ray exit window 22 , an electron emitter 23 , and an X-ray rotating anode 10 . The electron emitter 23 and the X-ray rotating anode 10 are disposed in the evacuated housing 21 .

[0076] A section of the housing 21 can form the X-ray exit window 22. Alternatively, the X-ray exit window 22 can be structurally distinguishable from the rest of the housing 21 and inserted into the housing 21 in a vacuum-tight manner.

[0077] The electron emitter 23 is typically arranged on the cathode side above the first focal zone 12 and the second focal zone 14. An acceleration voltage is applied between the electron emitter 23 and the X-ray rotating anode 10, by means of which the emitted electrons are accelerated toward the X-ray rotating anode 10.

[0078] The electron emitter 23 can be a thermionic emitter, such as an emitter plate or an emitter coil. Alternatively, the electron emitter 23 can be a field effect emitter, such as a field effect emitter made of silicon. The field effect emitter can have an emission surface of such a size that the electrons can be aligned with the first focal zone 12 and / or the second focal zone 13 without a deflection unit.

[0079] The electrons of the electron emitter 23 are preferably aligned such that they impinge only on the first focal zone 12, only on the second focal zone 13 or simultaneously on the first focal zone 12 and the second focal zone 13. The alignment of the electrons can be performed by means of a deflection unit.

[0080] The X-ray exit window 22 is preferably designed to filter the X-rays generated in the middle section 14. For this purpose, the X-ray exit window 22 can comprise, in particular, beryllium and / or titanium and / or aluminum.

[0081] Figure 8 A longitudinal section along the axis of rotation R of an X-ray radiator 30 according to the invention is shown.

[0082] The X-ray radiator 30 includes an X-ray tube 20 and a filter unit 31 for filtering the X-rays generated in the central section 14. The filter unit 31 is arranged outside the evacuated housing 21. The filter unit 31 can be configured as a collimator, for example. The filter unit 31 is particularly arranged in the beam path of the useful X-ray radiation so that the X-rays generated in the central section 14 can be reduced.

[0083] The filter unit 31 can in particular comprise aluminum and / or titanium for filtering. The filter unit 31 can in particular be designed as a disk made of aluminum with a thickness of 2.5 mm.

[0084] Although the details of the present invention have been illustrated and described in detail through the preferred embodiments, the present invention is not limited to the disclosed examples and other variations can be derived therefrom by those skilled in the art without departing from the scope of protection of the present invention.

Claims

1. An X-ray rotating anode (10), comprising: - a carrier body (11) consisting of molybdenum and / or a molybdenum alloy, a first focal zone (12) formed on the carrier (11), a second focal zone (13) formed on the carrier (11), - wherein the first focal zone (12) and / or the second focal zone (13) comprises tungsten and / or rhenium, It is characterized by: - the first focal zone (12) and / or the second focal zone (13) are formed on the carrier (11) by means of a VPS coating method, and The first focal zone (12) and the second focal zone (13) are spaced apart from one another by an intermediate section (14) in the carrier (11) between the first focal zone (12) and the second focal zone (13).

2. The X-ray rotating anode (10) according to claim 1, The intermediate section (14) comprises a connecting plate (15) which is bounded on one side by the first focal zone (12) and on the other side by the second focal zone (13).

3. The X-ray rotating anode (10) according to claim 1, The intermediate section (14) comprises a shaft (16) which is bounded on one side by the first focal zone (12) and on the other side by the second focal zone (13).

4. The X-ray rotating anode (10) according to claim 1, The lower side of the first focal zone (12) and the lower side of the second focal zone (13) are parallel to the surface plane of the middle section (14).

5. The X-ray rotating anode (10) according to claim 1, The surface of the carrier (11) has a first groove (17) and a second groove (18), wherein the first focal zone (12) is formed in the first groove (17) and the second focal zone (13) is formed in the second groove (18).

6. The X-ray rotating anode (10) according to claim 1, 2 or 5, The first focal zone (12), the middle section (14) and the second focal zone (13) are designed to be parallel to one another.

7. The X-ray rotating anode (10) according to claim 1, 3, 4 or 6, The first focal zone (12), the middle section (14) and the second focal zone (13) are designed in a stepped manner relative to one another.

8. The X-ray rotating anode (10) according to any one of claims 1 to 4, The first focal zone (12) and the second focal zone (13) are formed in a stepped manner with respect to the sections of the carrier plate (11) connected to the first focal zone (12) and the second focal zone (13).

9. The X-ray rotating anode (10) according to claim 1, 5 or 6, The first focal zone (12) and the second focal zone (13) are designed to be plane-parallel with respect to sections of the carrier plate (11) connected to the first focal zone (12) and the second focal zone (13).

10. The X-ray rotating anode according to any one of the preceding claims, The first focal zone (12) and the second focal zone (13) are formed in a common production step on the carrier (11) so as to be continuous and are subsequently separated by forming the intermediate section (14).

11. An X-ray tube (20) comprising: - an evacuated housing (21) having an X-ray exit window (22), - an electron emitter (23), and - an X-ray rotating anode (10) according to any one of the preceding claims, - wherein the electron emitter (23) and the X-ray rotating anode (10) are arranged in the evacuated housing (21).

12. The X-ray tube (20) according to claim 11, The X-ray exit window (22) is configured to filter X-rays generated in the middle section (14).

13. The X-ray tube (20) according to claim 12, The X-ray exit window (22) comprises beryllium and / or titanium and / or aluminum for filtering.

14. An X-ray radiator (30) comprising: - An X-ray tube (20) according to any one of claims 11 to 13, and - a filter unit (31) for filtering the X-rays generated in the middle section (14), wherein the filter unit (31) is arranged outside the evacuated housing (21).

15. The X-ray radiator (30) according to claim 14, The filter element (31) comprises aluminum and / or titanium.

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