Computed tomography scanner and method of operating a computed tomography scanner

Abstract

The invention relates to a computed tomography scanner comprising a static radiator-detector ring (10) which is composed of an odd number (n) of radiator-detector elements (11, 12, 13, 14, 26), one unique radiator-detector element (26) of which is movable relative to the remaining, jointly describing C-shaped radiator-detector elements (11, 12, 13, 14) such that the radiator-detector ring (10) is opened, wherein each radiator-detector element (11, 12, 13, 14, 26) has an anode system (9) arranged for emitting X-rays which extends over an angle a of at least 0.9 x 360° / n on the circumference of the radiator-detector ring (10) and a detector (4) arranged for detecting X-rays which extends over an angle β of at least 0.95 x 360° / n within the same radiator-detector element (11, 12, 13, 14, 26), and each anode system (9) is part of a radiator system (18) comprising a plurality of electron emitters (5, 25), each of which is designed to produce a focal point (BF ‑ , BF, BF + ) on the anode system (9) in one of at least three selectable positions in cooperation with an electrode system (21).

Description

Technical Field

[0001] This invention relates to a computed tomography (CT) scanner comprising a static radiator-detector ring, i.e., a radiator-detector ring that does not rotate during operation of the CT scanner. Additionally, this invention relates to a method for operating such a CT scanner. Background Technology

[0002] Computed tomography (CT) scanners can, in principle, operate using either a rotating radiator-detector unit or a fixed X-ray emitter and associated detector. WO2018 / 086744A2 describes a possible configuration of a CT scanner with a non-rotating radiator-detector unit.

[0003] EP1474040B1 discloses an imaging apparatus for X-ray technology, comprising a gantry frame in which an X-ray source and associated detector are rotatably supported. A sector segment can be removed from the generally annular gantry to allow the object to be imaged to be positioned in the central imaging region of the gantry ring. Guiding devices for the radiation source and detector are also found in the removable sector segment.

[0004] US 6,113,264 A describes another X-ray technology apparatus having a generally annular radiator-detector system with a movable sector segment for opening the ring. In this case, the movable sector segment can move along the circumference of the annular radiator-detector system.

[0005] Documents US 7,001,045B2 and EP3646793A2 describe computed tomography scanners with different structures, featuring annular radiator-detector assemblies that can be adjusted in a variety of ways.

[0006] For example, the literature WO2010 / 078481A1 and DE102016208123B4 describes a computed tomography scanner that is movable as a whole.

[0007] DE102010028438A1 describes an X-ray instrument constructed as a C-arm device, which uses carbon nanotubes as electron emitters. The scanning trajectory detailed in DE102010028438A1 can be achieved using multiple X-ray sources arranged differently in space. Summary of the Invention

[0008] The object of this invention is to provide the possibility of X-ray imaging using a static radiator-detector ring, which is a further development of the prior art, and which should provide good operability and excellent imaging quality with a relatively uncomplicated device structure.

[0009] According to the invention, this objective is achieved by a computed tomography scanner according to the invention. This objective is also achieved by a method for operating a computed tomography scanner according to the invention. The structural design and advantages of the invention described below with respect to the operating method also apply accordingly to the device, i.e., to the computed tomography scanner, and vice versa.

[0010] The computed tomography scanner according to the invention comprises a static radiator-detector ring consisting of an odd number n of radiator-detector elements, a single radiator-detector element being movable relative to the remaining radiator-detector elements that collectively form a C-shape, such that the radiator-detector ring is opened. Each radiator-detector element has an anode system configured to emit X-rays, extending at an angle α of at least 0.9 × 360° / n on the circumference of the radiator-detector ring, and a detector configured to detect X-rays, extending within the same radiator-detector element at an angle β of at least 0.95 × 360° / n. Each anode system is part of a radiator system comprising a plurality of electron emitters, each electron emitter being designed to produce a focal point at one of at least three selectable locations on the anode system in cooperation with an electrode system. In this context, the focal points generated by the same electron emitter can be selectively positioned, particularly arranged side-by-side along the circumferential direction of the radiator-detector ring, i.e., arranged at different angular positions around the central axis of the computed tomography scanner, especially at equal intervals. The switching between different focal point positions, achieved by progressively changing the settings of the electrode system, is called Beam Toggling.

[0011] The operating method according to this application proceeds from this premise, namely, using a computed tomography scanner comprising a non-rotating radiator-detector ring composed of an odd number of radiator-detector elements, i.e., sector segments, a single sector segment of which is designed to open the radiator-detector ring. Multiple electron emitters are arranged not only in the fixed radiator-detector elements but also in the radiator-detector elements to be opened. These electron emitters are each designed to generate a focal point with a variable position on the anode of the radiator-detector element by means of electrodes influencing the electron beam, such that the total number of possible focal point positions is equivalent to a multiple of the number of electron emitters, and the maximum angular distance between two focal points arranged side-by-side along the circumference of the radiator-detector ring within the same radiator-detector element is less than the minimum angular distance between the focal points of two adjacent radiator-detector elements. The operating method includes the following steps:

[0012] - Position the radiator-detector ring around the object being inspected, wherein the radiator-detector ring is first opened and at the latest closed in the position set for X-ray technical inspection.

[0013] - The fan-shaped X-ray beam emitted from the first focal point is aligned with the object being inspected, wherein the X-rays are detected by detectors of at least two radiator-detector elements.

[0014] - A second focal point is generated, which is offset from the first focal point by a first angular difference on the circumference of the radiator-detector ring, and does not necessarily have to be arranged immediately adjacent to the first focal point.

[0015] - Generate additional focal points, which are offset from the previous focal point by an angular difference on the circumference of the radiator-detector ring, wherein the difference between two successive angular differences is less than the difference between the minimum angular distance between the focal points in adjacent radiator-detector elements and the maximum angular distance between two adjacent focal points within the same radiator-detector element.

[0016] This invention is based on the consideration that a computed tomography scanner with an openable radiator-detector ring offers advantages in X-ray preparation compared to a conventional computed tomography scanner with a permanently closed radiator-detector ring. For example, the openable radiator-detector ring can be pushed from the side onto a table where a patient is lying. Despite the possibility of opening the radiator-detector ring, a mass-saving structure is advantageous when there are a large number of focal positions simultaneously, namely, that multiple different focal positions can be selectively set for each electron emitter. Generally, the anode, positioned on the circumference of the radiator system, occupies at least 90% of the circumference, i.e., 324°. Since the number of radiator-detector elements is odd, one mating point between two radiator-detector elements is never precisely diametrically opposite to another such mating point. If a focal point is located in the edge region of a radiator-detector element, that is, near a mating point, then the X-rays emitted from this focal point are directed onto two X-ray detectors arranged side-by-side along the circumferential direction, such as photon counting detectors. In particular, the use of row detectors can be considered. Please refer to WO 2019 / 057339 A1 for this information. In general, scintillation counters, which can be of any form, can also be used as X-ray detectors. Compared to the anode of the radiator-detector ring, the detector extends at a larger angle in any case, i.e., over at least 95% of the circumference, that is, over an angle of at least 342° in total, distributed across the various sector segments of the radiator-detector ring.

[0017] The degree of overlap or misalignment of possible focal positions within the same radiator-detector element is much smaller than the minimum angular distance between focal positions that may exist in adjacent radiator-detector elements. If all possible focal positions are selected sequentially along the circumferential direction of the radiator-detector ring, then much larger jumps in angular adjustment will typically occur after several small angular distances (i.e., when switching from one radiator-detector element to the next). The operating method according to this application provides an averaging of the angular distance between a focal position and the next focal position in the time flow. In this case, multiple cycles (one rotation is one cycle) around the central axis of the radiator-detector ring can be described by continuous switching between different focal positions, where all possible focal positions are occupied only after multiple cycles. In particular, the focal point is generated by mutually different settings of the electrodes affecting the electron beam during each individual cycle. This could mean, for example, that during a virtual X-ray source cycle, the first electrode system is configured such that a centrally oriented, neutral electron beam is retained, while the second electrode system, belonging to another electron emitter, ensures that the corresponding electron beam is deflected in a predetermined direction relative to its neutral orientation, which occurs as the focus shifts on the circumference of the radiator-detector ring.

[0018] The following simplified examples illustrate the possibility of continuously adjusting the X-ray angle setting during computed tomography (CT) scan operation, i.e., the possibility of switching between different possible focal positions:

[0019] A radiator-detector ring consists of only three radiator-detector elements, each extending at an angle of approximately 120°. The mating point between the first and third radiator-detector elements is at 0°. Viewed along the circumference of the radiator-detector ring, the centers of the three sector segments are therefore located at 60°, 180°, and 300°.

[0020] For simplicity, assume that each radiator-detector element has only two electron emitters, where the electron beam emitted by one emitter can be aligned with the associated anode system in three different ways:

[0021] The electron beam is aligned with the anode either centrally or deflected clockwise or counterclockwise, wherein the direction of deflection indicates the circumferential direction of the reference radiator-detector ring.

[0022] The equidistant distances between possible focal positions within the first radiator-detector element are given, for example, by the following focal positions: 20°, 36°, 52°, 68°, 84°, and 100°. In this case, the first three values ​​are assigned to the first electron emitter, and the values ​​68°, 84°, and 100° are assigned to the second electron emitter. The centering orientation of the electron beam corresponds to a focal position of 36° (first electron emitter) or 84° (second electron emitter). In a few examples already discussed, starting from a small number of electron emitters, the electron beam can be deflected relative to the corresponding centering orientation, such that focal positions are offset by ±16° relative to the focal position generated in the case of centering the electron beam. Therefore, there is always a 16° angular distance between a focal position within the first radiator-detector element and the next possible focal position within the same radiator-detector element.

[0023] Similarly, focal positions of 140°, 156°, 172°, 188°, 204°, and 220° can be selected within the second radiator-detector element, and focal positions of 260°, 276°, 292°, 308°, 324°, and 340° can be selected within the third radiator-detector element. The first radiator-detector element is the sector segment of the radiator-detector ring that needs to be opened. The second and third radiator-detector elements are firmly connected. Although the radiator-detector elements differ from each other in their mechanical functions, all radiator-detector elements are configured to be identical in terms of their X-ray technical function, particularly in the arrangement of the X-ray source (i.e., the focal point on the anode) and the arrangement of the X-ray detector. Therefore, during the performance and evaluation of computed tomography (CT) scans, i.e., X-ray examinations, it is unnecessary to consider the degree to which one radiator-detector element can be adjusted relative to the remaining radiator-detector elements.

[0024] To ensure the desired adjustability of one of the radiator-detector elements, while configuring all radiator-detector elements identical in terms of their X-ray technical functionality, only a portion of the usable 120° structural space within each radiator-detector element can be used by the corresponding anode system. Therefore, there is an angular distance between the outermost possible focal position of one radiator-detector element and the smallest focal position of the next radiator-detector element, which is much larger than the angular distance between focal positions within the same radiator-detector element. In the present case, the minimum angular distances across elements between the focal positions of different radiator-detector elements are as follows: a 40° angular distance between the first and third elements (20° or 340°), and also a 40° angular distance between the first and second elements (100° or 140°) and between the second and third elements (220° or 260°).

[0025] If we now set all possible focal positions in a clockwise (or counterclockwise) direction (which simulates the mechanical rotation of an X-ray source around the longitudinal axis of a computed tomography scanner), then after five 16° angle changes, there will always be a 40° angle change, followed by five more 16° jumps.

[0026] This unevenness in angle jump can be compensated for by using a new mode and sequentially setting different focus positions according to that mode:

[0027] Starting from the first possible position of a focal point in a clockwise direction, i.e., the 20° position, six virtual cycles are initiated. In this simplified example, only three focal positions are selected sequentially in each cycle (each full rotation), and these focal positions are offset from each other by an average of 120°. Specifically, the possible order of the focal positions is as follows: 20°, 140°, 276°, 52°, 172°, 308°, 84°, 204°, 340°, 100°, 220°, 324°, 68°, 188°, 292°, 36°, 156°, 260°. Thus, after six virtual cycles, each of the 18 possible focal positions has been selected exactly once. In this scenario, starting from an average 120° angular distance, the upward or downward deviation does not exceed 16°, with eight 120° angular distances and five each of 136° or 104° angular distances, and the value of 104° never immediately follows the value of 136° (and vice versa). This also applies to starting six virtual cycles again, that is, to the switch from a 260° position to a 20° position, which corresponds to an exact 120° angular difference.

[0028] Therefore, in the observed, simplified example, only three different values ​​appear as angular differences: 104°, 120°, and 136°. The difference between two successive angular differences (i.e., 0° or 16°) is less than the angular distance between the closest focal points of the two radiator-detector elements. In the present case, this difference is even less than half of the aforementioned 40° angular distance extending along the edge of the sector segment. Subtracting the uniform 16° angular distance within the sector segment (as described in the example) from this angular distance across the sector segment yields a difference of 24°, which is always still greater than the maximum difference between successive angular differences over time. Although the segmentation of the radiator-detector ring and its opening mechanism result in a non-uniform distribution of focal points on the circumference of the radiator-detector ring, it is still possible to transmit X-rays, which are essentially fan-shaped beams emitted from a single focal point, through a relatively uniform (simulating X-ray source rotation) angular jump pattern onto the object being examined.

[0029] Each focal point is located on an anode system, which may include one or more liquid-cooled or uncooled anodes for each X-ray tube. For example, the anodes described in DE 10 2017 008 810 A1 can be used. Regardless of the anode design, a computed tomography scanner can be designed to simultaneously generate two or more focal points offset from each other on the circumference of the radiator-detector ring via the radiator-detector element. In the case of exactly two focal points and corresponding two X-ray beams (used to examine the volume of interest), this can also be described as a stereotactic approach to X-ray imaging.

[0030] Regarding the design of the cathode used as an electron emitter in a computed tomography scanner, for example, the possibility of selecting from WO2019 / 057338 A1 (which claims priority to the aforementioned patent application DE 10 2017 008 810 A1).

[0031] For example, the possibility of manipulation is described in WO 2019 / 042587 A2, and this possibility can also be applied to the current situation. In the fabrication of a cathode designed for emitting electrons, all the solutions described in documents WO 2018 / 086737A1 and WO 2018 / 141485 A1 can be utilized, for example.

[0032] In general, the X-ray tube of a computed tomography (CT) scanner can be designed to generate a series of X-ray pulses that differ from each other in various parameters, particularly in the duration, intensity, X-ray dose, and frequency of each pulse. For this purpose, variations in the voltage present at the anode and the electron flux emitted from the cathode can be specified. These possibilities for altering the X-ray source are particularly advantageous when combined with a photon-counting detector suitable for distinguishing various X-ray frequencies, i.e., inherently suited for multi-energy and multi-dose operating modes.

[0033] The computed tomography (CT) scanner can be a mobile or stationary X-ray instrument. The CT scanner is particularly suitable for examining the chest area. Attached Figure Description

[0034] Embodiments of the present invention will now be described in detail with reference to the accompanying drawings. The drawings show:

[0035] Figure 1 This is an overview image of a computed tomography (CT) scanner;

[0036] Figure 2 It is similar to a computed tomography (CT) scanner. Figure 1 The diagram shows that the radiator-detector loop is open;

[0037] Figure 3 and 4 These are multiple magnified images of details from a computed tomography (CT) scan;

[0038] Figures 5 to 7 It is the X-ray tube of a computed tomography (CT) scanner;

[0039] Figure 8 It is a radiator-detector element of a computed tomography scanner, consisting of an X-ray tube and associated detectors;

[0040] Figure 9 and 10 This is a schematic diagram showing details of a computed tomography (CT) scanner. Detailed Implementation

[0041] The computed tomography scanner generally labeled with reference numeral 1 includes a fixed gantry 2, where the term "fixed" means that the radiator-detector-unit does not rotate about the central axis MA of the gantry 2 during X-ray acquisition. More precisely, fan-shaped beams of X-rays RS are generated by means of X-ray tubes 3 and associated X-ray detectors 4 distributed around the entire circumference of the gantry 2, which are emitted from a focal point BF on the anode 6 of the X-ray tube 3. Each X-ray tube 3 may be equipped with multiple cathodes 5, 25 as electron emitters. In the schematically illustrated embodiment, each X-ray tube 3 has a unique elongated anode 6, which in this case also serves as the anode system 9. Alternatively, the anode system 9 of the X-ray tube 3 may consist of multiple anodes 6.

[0042] The scanning gantry 2 is mounted on a movable platform 7 in various adjustable ways. Furthermore, the scanning gantry 2 can rotate around a horizontal rotation axis perpendicular to the central axis MA. The scanning gantry 2 can also move longitudinally along the horizontally set central axis MA. Additionally, the scanning gantry 2 can be adjusted to a limited extent along its circumference. The entire scanning gantry 2 can also be raised or lowered. In this embodiment, in addition to the movable platform 7, there is a separate operation and analysis evaluation unit 8. It is also possible to structurally integrate the movable platform 7 with the operation and analysis evaluation unit 8.

[0043] No housing is provided to enclose the scanning gantry 2. More precisely, the entire scanning gantry 2 is configured as a radiator-detector ring 10, which consists of a total of five radiator-detector elements 11, 12, 13, 14, and 26. In this case, the radiator-detector elements 11, 12, 13, and 14 are fixed and rigidly connected to each other, while the radiator element 26 is movable to open the radiator-detector ring 10. The purpose of opening is to use the radiator-detector ring 10 to enclose a patient examination bed 15. The opening mechanism is configured as a sliding mechanism 16. Figure 1 As shown, starting from the closed radiator-detector ring 10, the radiator-detector element 26 is first slightly moved longitudinally along the central axis MA, that is, pushed out of the radiator-detector ring 10. With the radiator-detector element 26 positioned beside the C-shaped arrangement of the remaining radiator-detector elements 11, 12, 13, and 14, the radiator-detector element 26 can move circumferentially along the C-shaped arrangement 11, 12, 13, and 14, thereby opening the opening on the circumference of the radiator-detector ring 10, as shown in... Figure 2As shown in the diagram, the radiator-detector element 26 is never tilted relative to the remaining radiator-detector elements 11, 12, 13, and 14. Because there is no tilting mechanism involving the radiator-detector element 26, the available structural space extending at a 72° angle along the circumference of the radiator-detector ring 10 can be used as much as possible for mounting X-ray technology components, which will be described in detail below.

[0044] In terms of the arrangement of the X-ray technology components, the movable radiator-detector element 26 is no different from the fixed radiator-detector elements 11, 12, 13, and 14. Each radiator-detector element 11, 12, 13, 14, and 26 has an identical [structure / feature]. Figures 5 to 8 The structure is shown in the diagram. The connector for the X-ray tube 3 is labeled 17. The radiator system 18 of the X-ray tube 3 emits X-rays RS in the following manner: (as shown in...) Figure 4 (As shown in the middle diagram) Of the five radiator-detector elements 11, 12, 13, 14, 26, two radiator-detector elements, more specifically their detector 4, are always radiated. Since the number of radiator-detector elements 11, 12, 13, 14, 26 is odd, one mating point between two radiator-detector elements 11, 12, 13, 14, 26 is never precisely diametrically opposite to the second such mating point.

[0045] Each X-ray tube 3 contains an emitter assembly 19 to generate an electron beam ES that strikes the anode system 9 and thus creates a focal point BF. The focal point BF does not necessarily have a near-point shape. Rather, it can be produced in a manner known in principle, for example, by creating an elongated focal point, wherein the position of the focal point BF should in any case be understood as the location of its midpoint.

[0046] In this embodiment, the emitter assembly 19 includes different cathodes 5, 25 to generate X-rays of different doses and / or wavelengths. Electrons are always extracted from the cathodes 5, 25 by means of an extraction grid 20, wherein the electron beam ES can be deflected in a defined manner by means of an electrode system 21 comprising multiple electrodes 22, 23. The multiple cathodes 5, 25 are collectively disposed on a circuit board 24.

[0047] The entire anode system 9, acting in conjunction with the emitter assembly 19 of the X-ray tube 3, extends at an angle α, significantly less than 72°, on the circumference of the radiator-detector ring 10. An angle β, representing the extension of the X-ray detector 4 on the circumference of the radiator-detector ring, is significantly closer to 72°. In other words, the gaps formed between the individual X-ray detectors 4 on the circumference of the radiator-detector ring 10 are much narrower than the gaps formed between the radiation systems 18. Multiple possible focal positions extend within the X-ray tube 3 at an angle γ, less than angle α.

[0048] The electrode system 21 is designed to selectively align the electron beam ES with a focus BF or a focus BF that is offset along the circumferential direction of the radiator-detector ring 10 compared to the original focus. + BF - .according to Figure 9 and 10 The arrangement, the focus of BF + The relative focus BF has deflected in a clockwise direction, while the focus BF... - The electron beam ES deflects counterclockwise, indicating a shift in focus BF. This deflection is also called Beam Toggling, and it causes the focus BF to shift... - BF, BF + It becomes possible to arrange them in a particularly close and staggered manner on the circumference of the radiator-detector ring 10. In this case, a total of hundreds of focal points can be achieved, which is many times the number of electron emitters 5 and 25.

[0049] List of reference numerals

[0050] 1. Computed Tomography Scanner

[0051] 2 Scanning Frame

[0052] 3 X-ray tubes

[0053] 4 X-ray detectors

[0054] 5. Type I cathode, electron emitter

[0055] 6 Anode

[0056] 7. Movable stand

[0057] 8. Operation and Analysis Evaluation Unit

[0058] 9. Anode System

[0059] 10 Radiator-Detector Loop

[0060] 11 First fixed radiator-detector element

[0061] 12 Second fixed radiator-detector element

[0062] 13 Third fixed radiator-detector element

[0063] 14. Fourth fixed radiator-detector element

[0064] 15 patient examination beds

[0065] 16 Sliding Mechanism

[0066] 17 Connectors

[0067] 18 Radiator System

[0068] 19. Transmitter Components

[0069] 20 Extracting the grid

[0070] 21 Electrode System

[0071] 22 electrodes

[0072] 23 electrodes

[0073] 24 circuit boards

[0074] 25 Type II cathode, electron emitter

[0075] 26. Portable radiator-detector element

[0076] Angle α, at which the anode system of the radiator-detector element extends.

[0077] β angle, the detector of the radiator-detector element extends at this angle.

[0078] The γ angle range, within which the possible focal point of the anode system lies.

[0079] BF Focus (General)

[0080] BF+ and BF- are focal points generated by an electron emitter (in the central position and at two positions offset along the circumferential direction of the radiator-detector ring).

[0081] ES electron beam

[0082] MA midline

[0083] RS X-ray

Claims

1. A computed tomography scanner comprising a static radiator-detector ring (10) composed of an odd number n of radiator-detector elements, a unique radiator-detector element being movable relative to the remaining radiator-detector elements that collectively form a C-shape, such that the radiator-detector ring (10) is opened, wherein each radiator-detector element has an X-ray emission area at least 0.9 × 3 on the circumference of the radiator-detector ring (10). An anode system (9) extending at an angle α of 60° / n and a detector (4) having an angle β of at least 0.95 × 360° / n within the same radiator-detector element for detecting X-rays, and each anode system (9) is part of a radiator system (18) comprising a plurality of electron emitters (5, 25), each electron emitter (5, 25) being designed to produce a focal spot (BF) at one of at least three selectable locations on the anode system (9) in cooperation with an electrode system (21). - BF, BF + ).

2. The computed tomography scanner according to claim 1, characterized in that: The radiator-detector element that is movable relative to the rest of the radiator-detector ring (10) is able to move along the axial direction of the radiator-detector ring (10) and, in the state of axial movement, can move in the tangential direction along the radiator-detector element which is generally arranged in a C-shape.

3. The computed tomography scanner according to claim 1, characterized in that: The radiator-detector element has an electron emitter (5, 25) designed for field emission of electrons.

4. The computed tomography scanner according to claim 3, characterized in that: Each radiator-detector element has at least one type-1 electron emitter and at least one type-2 electron emitter.

5. The computed tomography scanner according to claim 4, characterized in that: Different types of electron emitters within a radiator-detector element differ from one another in terms of their materials and / or geometry.

6. The computed tomography scanner according to any one of claims 3 to 5, characterized in that: The radiator-detector element is designed to switch between different X-ray frequencies and / or X-ray doses, wherein each focal point (BF) - BF, BF + It can be selected in the same way as the source for all configurable X-ray frequencies and X-ray doses.

7. The computed tomography scanner according to any one of claims 1 to 5, characterized in that: The radiator-detector ring (10) is mounted in an adjustable manner on a movable frame (7).

8. The computed tomography scanner according to any one of claims 1 to 5, characterized in that: The radiator-detector ring (10) includes at least five and at most nine radiator-detector elements, all of which, including movable radiator-detector elements, cover the same large angular range.

9. The computed tomography scanner according to any one of claims 1 to 5, characterized in that: The focal points of the same anode system (9) that are furthest apart from each other are clamped at an angle γ of at least 0.85×α on the circumference of the radiator-detector ring, and from each of the possible focal point positions, a fan-shaped X-ray beam can be directed at at least two radiator-detector elements on the radiator-detector ring (10) that are diametrically opposite the focal point.

10. The computed tomography scanner according to any one of claims 1 to 5, characterized in that: The radiator-detector element is designed to simultaneously generate at least two focal points that are offset relative to each other on the circumference of the radiator-detector ring (10).

11. The computed tomography scanner according to claim 3, characterized in that: The electron emitter is an electron emitter that includes carbon nanotubes.

12. A method for operating a computed tomography scanner (1), the computed tomography scanner comprising a non-rotating radiator-detector ring (10) consisting of an odd number of radiator-detector elements, a single radiator-detector element of which is designed to open the radiator-detector ring (10), wherein a plurality of electron emitters (5, 25) are provided not only in the fixed radiator-detector elements but also in the radiator-detector elements to be opened, each of the electron emitters being designed to generate a focal point (BF) with a variable position on an anode (6) associated with a radiator-detector element by means of an electrode influencing the electron beam. - BF, BF + The method comprises the following steps: ), such that the total number of possible focal positions is equivalent to many times the number of electron emitters (5, 25), and the maximum angular distance between two focal positions arranged side-by-side in the same radiator-detector element along the circumferential direction of the radiator-detector ring (10) is less than the minimum angular distance between the focal positions of two adjacent radiator-detector elements. - Position the radiator-detector ring (10) around the object to be inspected, wherein the radiator-detector ring (10) is closed at the latest in the position set for X-ray technical inspection. - Align the fan-shaped X-ray beam emanating from the first focal point with the object being examined, wherein the X-rays are detected by a detector (4) of at least two radiator-detector elements. - A second focus is generated, which is offset from the first focus by a first angular difference on the circumference of the radiator-detector ring (10). - Generate additional focal points, which are offset from the previous focal point by an angular difference on the circumference of the radiator-detector ring (10), wherein the difference between two successive angular differences is less than the difference between the minimum angular distance between the focal positions in adjacent radiator-detector elements and the maximum angular distance between two adjacent focal positions within the same radiator-detector element.

13. The method according to claim 12, characterized in that: Multiple loops around the central axis (MA) of the radiator-detector ring (10) are described by continuously switching between different focal positions, wherein all possible focal positions are occupied only after multiple loops.

14. The method according to claim 13, characterized in that: In each individual cycle, a focal point (BF-, BF, BF+) is generated by different settings of the different electrodes that affect the electron beam.

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