C-ARM X-RAY

Description

[0001] The invention relates to a C-arm X-ray device, i.e., an X-ray device having a C-shaped arm on which an X-ray source and an associated X-ray detector are mounted. Furthermore, the invention relates to a method for operating a C-arm X-ray device.

[0002] Various C-arm X-ray devices are known, for example, from documents DE 10 2009 033 607 A1, DE 10 2008 059 455 A1, DE 10 2010 028438, and US Pat. No. 8,559,591 B2. In the latter case, an X-ray source comprises field emission cathodes based on carbon nanotubes (CNT cathodes). An X-ray device with CNT cathodes is also known from WO 2009 115982.

[0003] A mobile C-arm X-ray device is disclosed, for example, in DE 10 2011 006 505 A1.

[0004] US8118488 discloses a tomography device in which an X-ray source and an X-ray detector can be moved within a ring-shaped housing held by a C-arm.

[0005] C-arm X-ray machines feature source-detector assemblies mounted on a C-shaped support, known as a C-arm. In hospitals, C-arm X-ray machines are used, for example, for intraoperative imaging.

[0006] The invention is based on the object of providing a C-arm X-ray device with enhanced imaging capabilities compared to the prior art.

[0007] This object is achieved according to the invention by a C-arm X-ray device with the features of claim 1. The subject matter of claim 1 consists in a C-arm X-ray device, with an X-ray emitter and an X-ray detector, which are held on a C-arm lying in a reference plane, wherein the X-ray emitter comprises nanorods as electron emitters and describes an elongated, tubular structure, characterized in that the X-ray emitter has a curved, elongated structure, wherein a tangent placed centrally on the X-ray emitter represents a surface normal of the reference plane and the curved shape of the X-ray emitter spans a plane aligned orthogonally to the reference plane, and wherein the total extension of the X-ray emitter is at least four times the diameter of the cross section of the X-ray emitter measured transversely to the elongated structure.The C-arm X-ray device according to the invention thus differs fundamentally from known C-arm devices, such as those disclosed in the aforementioned US Pat. No. 8,559,591 B2, in which an arrangement of multiple X-ray sources is located in the reference plane. The alignment of the X-ray source transverse to the reference plane largely enables the generation of cross-sectional images of an examination subject without any adjustment of the C-arm. This promotes both time-saving operation of the C-arm X-ray device suitable for tomography and high-quality generated image data.

[0008] In a simple design, which does not fall within the scope of the claim, the X-ray tube of the C-arm X-ray device has a straight, elongated, essentially cylindrical shape. The central axis of the X-ray tube, in particular the longitudinal axis of the cylinder, is identical to a surface normal of the reference plane.

[0009] In a modified design, the X-ray tube has a curved shape, with a tangent placed centrally on the X-ray tube representing a surface normal to the reference plane. Overall, the curved X-ray tube forms a plane that is orthogonal to the reference plane. The curvature of the X-ray tube can be designed, for example, in the form of a circular arc or a U-shape.

[0010] If one imagines the two ends of a U-shaped X-ray tube joining together, one arrives at a ring-shaped X-ray tube. In such a configuration, two parallel tangents placed on the X-ray tube each represent a surface normal to the reference plane defined by the C-arm. The ring-shaped X-ray tube can be designed either as an open or a closed ring. In the case of a closed ring, in particular a circular shape, the length of a closed line running centrally through the entire ring, in particular a circle whose diameter corresponds to the mean value between the inner diameter and the outer diameter of the overall ring-shaped X-ray tube, indicates the entire extension of the X-ray tube in the longitudinal direction of the elongated structure.

[0011] Instead of a ring shape, the X-ray tube can also have a polygonal shape, for example. The length of the X-ray tube in the longitudinal direction of the elongated structure is defined as the sum of the lengths of the individual sides of the polygon, with the side lengths being measured at the center of the X-ray tube's cross-section. Spatially, the polygonal X-ray tube represents a modification of a torus. A ring shape, i.e., a torus shape, or a polygonal shape can also be formed by an arrangement of multiple X-ray tubes, each containing nanorods.

[0012] Regardless of whether the X-ray source is completely straight or curved, whether in an open arc or in a closed ring, the total extension of the X-ray source in any section of the elongated structure measured in its longitudinal direction is at least four times the maximum diameter of the cross-section of the X-ray source measured transversely to the elongated structure.

[0013] The cathodes of the X-ray source, intended for the emission of electrons, preferably comprise carbon nanotubes in the form of nanorods. The very high electrical and thermal conductivity of carbon nanotubes enables high current-carrying capacity without significant heat generation in the individual carbon nanotubes themselves. Carbon nanotubes exhibit a low field strength threshold of less than 2 V / m for the field emission of electrons. The field strength threshold for cathodes for the emission of electrons containing carbon nanotubes can be lowered even further by arranging the carbon nanotubes in a preferred vertical direction on the cathode surface. Since single-walled carbon nanotubes are semiconductors and multi-walled carbon nanotubes are metallic conductors, multi-walled carbon nanotubes are particularly suitable for applications as electron emitters on the cathodes of the X-ray source.

[0014] In addition to carbon nanotubes, other types of nanorods, commonly referred to as nanosticks, are also suitable for the emission of electrons within the X-ray tube. In a preferred embodiment, such nanosticks are used to form field emission cathodes as the cathodes of the X-ray tube.

[0015] The cathode nanosticks are preferably made of a material that exhibits the lowest possible electron work function for field emission of electrons, based on the quantum mechanical field emission effect. The nanosticks have a uniform or non-uniform composition and are either hollow, i.e., tubes, or solid. The cathodes can comprise nanosticks of the same type or a mixture of different types, with the term "type of nanosticks" referring to their material composition and modification.

[0016] Suitable materials in pure or doped form for the field emission of electrons include single- or multi-walled carbon nanotubes, single- or multi-walled heteronitrogen carbon nanotubes, rare earth borides, in particular lanthanum hexaboride and cerium hexaboride, metal oxides, in particular TiO 2 , MnO, ZnO and Al 2 O 3 , metal sulfides, in particular molybdenum sulfide, nitrides, in particular boron nitride, aluminum nitride, carbon nitride, gallium nitride, carbides, in particular silicon carbide, silicon. Rod-shaped, optionally hollow, elements made of polymeric materials are also suitable as starting materials for producing the nanosticks, which emit electrons when the cathodes are operated. The cathode nanosticks are optionally manufactured from starting materials that only partially contain polymer materials, in particular in the form of a coating.

[0017] In a particularly preferred embodiment, the cathodes have nanosticks on their surface in a preferred vertical direction, i.e., toward the anode of the X-ray emitter. When the X-ray emitter is operating and sufficiently spaced apart, very strong electric fields can be generated at the tips of the nanosticks, which significantly simplifies the emission of electrons.

[0018] In one possible embodiment of the C-arm X-ray system, more than one type of cathode is arranged in the vacuum tube of the X-ray tube. The term "type" can refer to both the geometry and other properties of the cathodes, such as the materials. Cathodes of the same and different types can, in principle, be electrically controlled sequentially in any desired manner. In addition to the cathodes themselves, differences in focusing can also occur. Combined with properties such as the surface geometry of the individual cathodes, this allows for the generation of different electron beams and, ultimately, different X-ray beams.

[0019] The nanorods of the cathode, for example, have a length of less than 20 µm and a diameter of less than 10 nm, with a density of at least 10 6 nanorods per cm 2 relative to the area of ​​the cathode. A screen printing process is particularly suitable for producing the cathode containing nanorods.

[0020] The X-ray tube of the C-arm X-ray machine can be designed to generate various X-ray images that differ from one another in terms of dose, i.e., to operate with dose modulation. Generally, X-rays of different wavelengths, such as those intended for multi-energy or dual-energy images, can be generated by varying the anode voltage settings. Multi-energy images are particularly suitable for angiography.

[0021] Regarding the design of the X-ray tube of the C-arm X-ray device and its operation, all designs and methods described in documents WO 2018 / 086737 A1 and WO 2018 / 141485 A1 are feasible. The detector of the C-arm X-ray device, for example, is a line detector.

[0022] Regardless of the design of the at least one X-ray source, the C-arm X-ray machine can generate consecutive X-ray pulses of different wavelengths in a preferred procedure. This allows different materials within the examination volume to be distinguished from one another with particularly high reliability and, at the same time, a short acquisition time.

[0023] According to an advantageous development, the C-arm X-ray device comprises, in addition to the at least one X-ray source containing nanorods, in particular carbon nanotubes, a further X-ray source. In the case of a ring-shaped or polygonal shape of the CNT X-ray source or other X-ray source comprising nanorods, the additional X-ray source is preferably arranged centrally in the ring-shaped or polygon-shaped X-ray source. Compared to the latter X-ray source comprising nanorods, the additional X-ray source, in a preferred embodiment, enables the emission of a higher X-ray dose. In particular, the additional X-ray source can be an X-ray source with a rotating anode. A common detector is assigned to the X-ray source, which has nanorods for emitting electrons, and the further X-ray source.The additional X-ray source can, in principle, be an X-ray source of any design. In particular, the additional X-ray source, like the annular or polygonal X-ray source, can have at least one cathode containing nanorods, in particular carbon nanotubes. For example, the additional X-ray source contains three electron emitters, each constructed as a surface emitter with nanorods. Especially when the emitter of the additional X-ray source is constructed with nanorods, the anode of this X-ray source can also be a non-rotating anode.

[0024] According to an alternative embodiment, the X-ray tube and the X-ray detector can be pivoted together about a rotational axis located in the reference plane. The rotational movements of the X-ray tube and the X-ray detector are preferably electronically synchronized. This results in a common virtual rotational axis for the X-ray tube and the X-ray detector. This embodiment is also suitable for a C-arm that cannot be pivoted as a whole and represents a mechanically simplified embodiment overall.

[0025] If the X-ray source and the X-ray detector are pivotable about the said axis of rotation, the C-arm X-ray device can be operated according to claim 17. In this case, a plurality of X-ray images are created which differ from one another both with regard to the setting of the C-arm in its tangential direction and with regard to the angular setting of the X-ray source and the X-ray detector with regard to their common axis of rotation. Preferably, when creating a set of X-ray images, the C-arm is fixed in a first number of different positions with regard to its adjustment in the tangential direction, wherein in each of these positions, X-ray images are generated with a second number of different angular settings of the X-ray source and X-ray detector, i.e. settings about the said axis of rotation.

[0026] The ability to pivot the X-ray tube and detector around the aforementioned axis of rotation is useful for tomosynthesis, among other things, and generally enables the creation of multi-plane images. Furthermore, the C-arm X-ray unit, even when the X-ray tube cannot be adjusted on the C-arm, offers the possibility of creating particularly high-quality X-ray images with little or no increase in equipment compared to conventional X-ray units, thanks to its design.

[0027] Below, several examples are explained in more detail using a drawing. These show: Fig. 1 and 2 a first embodiment of a C-arm X-ray device in different operating positions, Fig. 3 and 4 a second embodiment of a C-arm X-ray device, Fig. 5 a third embodiment of a C-arm X-ray device, Fig. 6 a fourth embodiment of a C-arm X-ray device, Fig. 7 in a simplified representation a detail of the C-arm X-ray device according to Fig. 1 with illustrated beam path of the X-rays emitted from different X-ray sources, Fig. 8 in different representations, at least in part, an annular X-ray source, Fig. 9 to 11 different schemes for the operation of an annular X-ray source, Fig. 12 an X-ray source with a cylindrical basic shape, Fig. 13 an arc-shaped X-ray source, Fig. 14 a scheme for the operation of the X-ray source according to Fig. 12, Fig. 15 to 20 different basic forms of further X-ray emitters, Fig. 21 another embodiment of a C-arm X-ray device in a schematic perspective view, Fig. 22 the C-arm X-ray device according to Fig. 22 in schematic front view, Fig. 23 and 24, components rotatable about a common virtual axis, namely an X-ray emitter and an X-ray detector, respectively, of the C-arm X-ray device according to Fig. 21 , Fig. 25the C-arm X-ray device according to Fig. 5 with compared to the setting after Fig. 5 different angular setting of the X-ray tube around a virtual axis of rotation running between the X-ray tube and the detector.

[0028] Unless otherwise stated, the following explanations refer to all embodiments.

[0029] A C-arm X-ray device 1 has a C-arm 2 that can be adjusted in many ways, to which an X-ray tube arrangement 3 and an associated X-ray detector 4 are attached. The adjustability of the C-arm 2 does not apply to the embodiment according to the Figures 21 to 24 In all embodiments, the C-arm 2 defines a reference plane, which, for example, in the arrangement according to Fig. 1 vertically and in the arrangement according to Fig. 2 is aligned horizontally.

[0030] In all exemplary embodiments, the X-ray source arrangement 3 comprises an X-ray source 5 of the first type, which comprises field emission cathodes with carbon nanotubes (CNTs). The X-ray source 5 has an elongated shape, optionally bent into a closed or nearly closed ring-shaped structure. This closed shape can also be formed by multiple X-ray sources 5. In no case is the ring shape formed by at least one X-ray source 5 or other ring- or frame-shaped closed shape completely filled, for example, in the shape of a square.

[0031] A tangent can be placed on a section of the X-ray tube 5 that has at least one longitudinal or tangential direction and is either straight or curved, which is oriented perpendicular to the reference plane spanned by the C-arm 2. If the X-ray tube 5 does not have a straight, rod-shaped form, it spannes a plane that is oriented orthogonal to the reference plane.

[0032] In addition to the X-ray source 5 of the first type, the X-ray source arrangement 3 in the embodiments according to the Fig. 1 , 3 and 6an additional X-ray source 6. This additional X-ray source 6 operates with a rotating anode (not shown) for cooling purposes and is therefore suitable for generating particularly high X-ray doses. The additional X-ray source 6, like the annular X-ray source 5, has nanorods for emitting electrons. In the exemplary embodiment, three planar electron emitters, each of which has nanorods, are arranged in the additional X-ray source 6.

[0033] In the design according to Fig. 1 The additional X-ray source 6 is located centrally in the disc-shaped space surrounded by the first X-ray source 5. The central axis of the additional X-ray source 6 coincides with the axis of symmetry of the ring-shaped X-ray source 5. The X-ray sources 5, 6 can be controlled independently of each other.

[0034] In the design according to Fig. 3The X-ray source 5 of the first type has an elongated, curved shape. Overall, the X-ray source 5 is aligned transversely to the reference plane defined by the C-arm 2. The curved X-ray source 5 defines a plane that is aligned perpendicular to the tilt axis of the C-arm 2, designated K. The tilt axis K lies in the reference plane. The additional X-ray source 6 is in the case of Fig. 3 next to the X-ray tube 5, first type, attached to the C-arm 2.

[0035] The embodiment according to Fig. 5 differs from the embodiment according to Fig. 3 by eliminating the additional X-ray source 6. Likewise, such an additional X-ray source 6 could be used in the embodiment according to Fig. 1 omitted.

[0036] The embodiment according to Fig. 6 is similar to the embodiment according to Fig. 3However, in this case, the X-ray tube 5 has a straight, rod-shaped configuration. The longitudinal axis of the rod-shaped X-ray tube 5 is identical to a surface normal of the reference plane formed by the C-arm 2. An additional, optional X-ray tube 6 is arranged according to Fig. 6 , as well as in the arrangement according to Fig. 3 , attached next to the first X-ray tube 5 at one end of the C-arm 2.

[0037] In Fig. 7 The beam path of X-rays emanating from the X-ray source 5 is illustrated. This assumes two point-like sources of X-rays. From each approximately point-like source, the X-rays spread out in such a way that they hit the entire, planar detector 4. Collimator devices that limit the beam path of the X-rays are provided in Fig. 7Not shown. Tomographic images of an examination object can be generated from a multitude of individual projection images, each acquired with a single X-ray source, without changing the spatial relationship between the C-arm 2 and the examination object. By means of the X-ray source 5 according to Fig. 7 A total of 96 X-ray sources of precisely defined positions are formed.

[0038] The Fig. 8 shown for the C-arm X-ray device 1 according to Fig. 1 A suitable X-ray tube arrangement 3 can be combined with an additional X-ray tube 6 (not shown here) if required. Vacuum feedthroughs are designated by 7, and emitter arrangements of the X-ray tube 5 are designated by 9.

[0039] The Fig. 9 to 11illustrate a possible operating mode of the ring-shaped X-ray tube array 3. All electron emitters of the X-ray tube array 3 are formed by field emission cathodes with carbon nanotubes (CNT). In the first step, for example, as shown in Fig. 9 marked, four emitters are controlled, each of which is spaced at a 90° angle from each other, i.e., on the X-axis or on the Y-axis. In the next steps, further projection images can be taken, for example, according to Fig. 10 or accordingly Fig. 11 In the case of Fig. 10 Starting from the emitter located on the X-axis between the second and third quadrants, further emitters are sequentially controlled in a circular order.

[0040] In contrast, in the case of Fig. 11emitters located in different quadrants are activated one after the other, so that two emitters are always controlled one after the other, between which, compared to the operating mode after Fig. 10 a large distance in the circumferential direction of the X-ray source 5 is given. Fig. 11 The operating mode illustrated has the advantage that three-dimensional images of acceptable quality can be obtained based on projection images generated with only a portion of the available emitters.

[0041] The Fig. 12 and 13 show in perspective, partly transparent ( Fig. 12 ) Illustration of the X-ray tubes 5 after Fig. 6 or after Fig. 3 . The Fig. 12 The anode of the X-ray source 5, designated 8, is cooled by an electrically non-conductive oil flowing through the anode 8. Each of the X-ray sources 5 defines a longitudinal direction, which in the case of Fig. 13is defined by the tangential direction of the arc described by the X-ray tube 5, whereby the tangent is to be placed centrally between the two ends of the arc. In the embodiment according to Fig. 12 LS denotes the total length of the X-ray source 5. The total length LS is always in the longitudinal direction of an elongated structure described by the X-ray source 5, in the case of Fig. 12 a cylinder with a circular cross-section.

[0042] The Fig. 14 serves to illustrate a possible operating mode of the X-ray tube 5 according to Fig. 12In this case, three CNT cathodes of the X-ray source 5 are initially controlled, which are located in the middle or at the two ends of the X-ray source 5. Regarding the subsequent control of the remaining electron emitters, various possibilities exist: For example, the remaining electron emitters can be activated linearly, which in principle corresponds to the operating mode according to Fig. 10 It is also possible to control individual emitters one after the other, which are further apart from each other, as already shown in principle by Fig. 11 Random activation of individual electron emitters is also possible.

[0043] In the Figures 15 to 20 are in addition to the ring-shaped X-ray source 5 according to Fig. 1Other possible shapes of X-ray tubes 5 that can be used for the C-arm device 1 are outlined. These include triangular, square, pentagonal, hexagonal, and decagonal shapes. Other closed shapes, such as an octagon, are also possible.

[0044] DS denotes the diameter of the cross-section of the elongated structure of the X-ray source 6. In the case of Fig. 15 the elongated structure is a torus. In the case of a non-circular cross-section of the elongated structure, as in the cases according to the Figures 16 to 20, DS is defined as the maximum diameter of the cross-section of the elongated structure. The partially dashed line along which the entire extension LS is to be measured is, in the case of a polygonal X-ray tube 5, bent several times according to the respective polygon shape. In all cases, the extension LS is more than four times the diameter DS.

[0045] In the in the Figures 15 to 20 In the cases outlined, the optional, additional X-ray source 6 is preferably located, as in the arrangement according to Fig. 1 , in the center of the respective mold. Thus, the reference plane defined by the C-arm 2 intersects the additional X-ray tube 6, while the X-ray tube 5, which operates with CNT emitters, protrudes from this reference plane on both sides.

[0046] In the example according to the Figures 21 to 24During an X-ray examination, the C-arm 2 is fixed in the room. Only the X-ray tube 5 and the X-ray detector 4 can be pivoted about a common, virtual axis of rotation D. The synchronization of the pivoting movements of the X-ray tube 5 and the X-ray detector 4 is done electronically. As can be seen from Fig. 21 As can be seen, the X-ray source 5 and the X-ray detector 4 each have an elongated basic shape. In the arrangement according to Fig. 21 The X-ray source 5 as well as the X-ray detector 4 are aligned transversely to the reference plane spanned by the C-arm 2. In the view according to Fig. 22 The reference plane is aligned orthogonally to the drawing plane, with the rotation axis D lying in the reference plane. An examination area U located between the X-ray source 5 and the X-ray detector 4 is intersected by the rotation axis D.

[0047] The X-ray source 5 of the X-ray device 1 according to Fig. 21is suitable for the emission of fan-shaped X-ray beams, wherein the plane in which the fan lies can be adjusted in many ways during an X-ray exposure by discontinuous or continuous pivoting of the X-ray source 5 about the rotation axis D. The low masses and moments of inertia of the X-ray source 5 and the X-ray detector 4 compared to the entire C-arm 2 enable consecutive X-ray exposures to be taken at different angular settings of the X-ray source 5 and the X-ray detector 4, wherein the assembly formed by the X-ray source 5 and the X-ray detector 4 can be stationary for each X-ray exposure. A set of projections generated in this way enables the provision of cross-sectional images and volume data with little equipment and time expenditure compared to conventional systems. The X-ray detector 4 in the embodiment according to Fig. 21a line detector is provided.

[0048] The X-ray source 5, like the X-ray detector 4, is adjustable in an angular range of at least +20° to -20°, as far as the adjustment around the rotation axis D is concerned. The adjustment can be made, for example, in 40 steps. If an additional Fig. 21 If adjustment in the tangential direction of the C-arm 2 is provided (not visible), i.e., around an imaginary transverse axis oriented perpendicular to the reference plane, i.e., in the longitudinal direction of the X-ray tube 5 and X-ray detector 4, provided they are in their center position, a multitude of possible settings results. For example, if adjustment of the C-arm around the transverse axis in 60 steps is provided, a total of 40 x 60 = 2,400 possible settings result for the assembly formed by the X-ray tube 5 and X-ray detector 4.

[0049] The adjustment of the X-ray source 5 around the rotation axis D, which intersects the X-ray source 5 and the X-ray detector 4 in the middle, is also in Fig. 25 , which the embodiment according to Fig. 5 shows, illustrated. In all other embodiments of the C-arm X-ray device 1 with an elongated, straight, or curved X-ray source 5, the adjustability of the latter about the rotation axis 5 can also be provided. List of reference symbols

[0050] 1C-arm X-ray device 2C-arm 3X-ray tube array 4X-ray detector 5X-ray tube of the first type (with nanorods) 6Additional X-ray tube 7Vacuum feedthrough 8Anode 9Emitter array DSDiameter of the cross-section of the elongated structure of the X-ray tube KTilt axis LExtension in the longitudinal direction of the elongated structure of the X-ray tube UExamination area

Claims

1. A C-arm X-ray apparatus comprising an X-ray emitter (5) and an X-ray detector (4) which are held on a C-arm (2) that extends in a reference plane, wherein the X-ray emitter (5) comprises nanorods as electron emitters and defines an elongated, hose-like structure, characterized in that the X-ray emitter (5) has a curved, elongated shape , wherein a tangent orientated on the centre of the X-ray emitter represents a surface normal of the reference plane, and the curved shape of the X-ray emitter spans a plane aligned orthogonally to the reference plane, and wherein the total extension of the X-ray emitter (5) is at least four times greater than the diameter of the cross section of the X-ray emitter (5) measured transversely to the elongated structure.

2. An X-ray apparatus according to Claim 1, characterized in that carbon nanotubes (CNT) are provided as nanorods for the emission of electrons.

3. The X-ray apparatus according to Claim 2, characterized in that at least some of the nanorods have the form of single- or multi-wall carbon nanotubes or single- or multi-wall heteronitrogen carbon nanotubes.

4. The X-ray apparatus according to Claim 2 or 3, characterized in that at least some of the nanorods contain borides of rare earth metals, metal oxides, metal sulphides, nitrides, carbides, or silicon.

5. The X-ray apparatus according to any one of Claims 2 to 4, characterized in that the nanorods have a length of less than 20 µm and a diameter of less than 10 nm, wherein a density of at least 106 nanorods per cm2 related to the area of the cathode designed for emitting the electrons is given.

6. The X-ray apparatus according to any one of Claims 1 to 5, characterized in that besides the X-ray emitter (5) that contains nanorods, in particular carbon nanotubes (CNT), it also comprises a further X-ray emitter (6).

7. The X-ray apparatus according to Claim 6, characterized in that the further X-ray emitter (6) has a rotating anode.

8. The X-ray apparatus according to any one of Claims 1 to 7, characterized in that the X-ray emitter (5) and the X-ray detector (4) can be swivelled together about an axis of rotation (D) aligned in the reference plane.

9. The X-ray apparatus according to Claim 8, characterized in that the X-ray emitter (5) is designed to emit fan-shaped X-ray beam bundles.

10. The X-ray apparatus according to Claim 8 or 9, characterized in that the X-ray emitter (5) and the X-ray detector (4) are synchronised electronically regarding revolutions about the axis of rotation (D).

11. The X-ray apparatus according to any one of Claims 8 to 10, characterized in that the C-arm (2) is displaceable in the tangential direction thereof, that is to say about a notional swivel axis aligned transversely to the reference plane.

12. A method for operating an X-ray apparatus according to Claim 11, wherein multiple X-ray images are created that differ from each other both in view of the adjustment of the C-arm (2) in the tangential direction thereof, and in view of the angular adjustment of the X-ray emitter (5) and the X-ray detector (4) with respect to their common axis of rotation (D).

13. The method according to Claim 12, characterized in that during creation of a set of X-ray images the C-arm (2) is fixed in a first number of different positions with regard to its displacement in the tangential direction, and in each of these positions X-ray images are generated with a second number of different angular settings between X-ray emitter (5) and X-ray detector (4).