Device and method for X-ray imaging, computer program and data carrier

Abstract

Device for X-ray imaging, comprising several X-ray sources (2-8), an X-ray detector with at least one detector element (10-19) and a control unit (20), wherein the control unit (20) is configured to alternately control the various X-ray sources (2-8) successively according to a predetermined control pattern to emit a respective X-ray pulse (21), such that the respective X-ray source (2-8) emits several X-ray pulses (21) within the framework of the control pattern, wherein a respective buffer memory (22) and a respective data acquisition unit (23) are assigned to the respective detector element (10-19), wherein the data acquisition unit (23) is configured to repeatedly write respective measurement data (24) of the assigned detector element (10-19) or processing data (42) determined from the respective measurement data (24) into the assigned buffer memory (22) synchronously with the control pattern.so that the respective measurement data (24) relate to X-ray radiation which, due to one of the X-ray pulses (21) assigned to the measurement data (24), falls on the respective detector element (10-19).

Description

[0001] The invention relates to a device for X-ray imaging, comprising several X-ray sources, an X-ray detector with at least one detector element, and a control unit. The invention also relates to a method for X-ray imaging, a computer program, and a data carrier.

[0002] In the field of X-ray imaging, both in medical diagnostics and in other applications such as non-destructive material testing and baggage scanners, system concepts are increasingly being described in which multiple discrete or distributed X-ray sources are sequentially controlled to enable 3D imaging with projections from as many spatial directions as possible. Various approaches exist for this, known, for example, as "static computed tomography," "non-mechanical CT," "fourth-generation CT," or "distributed-source tomosynthesis."

[0003] In most designs that incorporate multiple sources, stationary anodes are used because rotating anodes would be too expensive and bulky. However, stationary anodes have limited thermal resistance, which in turn restricts the applications for such tomography or tomosynthesis systems.

[0004] In current, third-generation rotating computed tomography (CT) scanners, for example, a power of 40 kW can be emitted per projection scan over an exposure interval of 200 µs to achieve a sufficient number of X-ray quanta at the detector and thus adequate image quality. To achieve comparable image quality, a similar number of X-ray quanta would also need to be detected using stationary anodes. However, due to the thermal limitations of stationary anodes, providing a sufficient X-ray dose would result in projection durations on the order of several milliseconds, as the stationary anodes can only absorb approximately 2 to 5 kW of power over the exposure period without being damaged. This long exposure time restricts the applications of static computed tomography to those that do not require high temporal resolution.For example, CT scans of the thorax, which require breath-holding, or a cardiac CT scan would be possible only to a very limited extent, if at all.

[0005] The invention is therefore based on the objective of improving the achievable temporal resolution of X-ray imaging, in particular using standing anodes, and thus opening up further areas of application for X-ray imaging with distributed standing anodes as X-ray sources.

[0006] The problem is solved by an X-ray imaging device comprising several X-ray sources, an X-ray detector with at least one detector element, and a control unit, wherein the control unit is configured to alternately control the various X-ray sources one after the other according to a predetermined control pattern to emit a respective X-ray pulse, so that each X-ray source emits several X-ray pulses within the framework of the control pattern, wherein each detector element is assigned a respective buffer memory and a respective data acquisition device, wherein the data acquisition device is configured to repeatedly write respective measurement data of the assigned detector element or processing data determined from the respective measurement data into the assigned buffer memory in a time-synchronous manner to the control pattern, so that the respective measurement data relate to X-ray radiation.which is due to one of the X-ray pulses that is assigned to the respective detector element.

[0007] The invention is based on the idea of ​​distributing the X-ray dose emitted by a single X-ray source during imaging across several time-spaced X-ray pulses. This approach takes advantage of the fact that a shorter continuous operating time or pulse duration allows for the use of higher power during the X-ray pulse. For example, by reducing the pulse duration to a few microseconds, a stationary anode can be loaded with an electron beam power of up to approximately 100 kW, thereby reducing the required exposure time for each projection by a factor of 20 to 50 compared to using a single continuous X-ray pulse for that projection.Since the time between the emission of different X-ray pulses by one of the X-ray sources is used to emit X-ray pulses by the other X-ray sources, the time required to acquire all projections can be significantly reduced, or the applied X-ray dose can be increased as needed for the same measurement time. The influence of the exposure time of an X-ray anode on the power it can absorb is already discussed in general in S. Bartzsch, U. Oelfke, Line focus x-ray tubes—a new concept to produce high brilliance x-rays, 2017 Phys. Med. Biol. 62 8600.

[0008] A dose of X-rays to be emitted can thus be distributed across several time-spaced, particularly ultrashort, X-ray pulses of, for example, a few microseconds or even less than 1000 nanoseconds, whereby the X-ray sources used are changed, particularly cyclically, so that the emission always occurs via a cold emitter, i.e., via an X-ray source whose anode temperature essentially corresponds to the ambient temperature. Since X-ray quanta originating from different X-ray sources are thus detected at different times by the detector element, the detector elements, i.e., individual pixels of a planar X-ray detector, are read out at a sufficiently high frame rate. This can be made possible by using separate buffer memories and data acquisition devices for the individual detector elements.

[0009] The X-ray detector can, in particular, have multiple detector elements or pixels to detect the X-ray intensity incident on each individual detector element. For example, each detector element can form a detector pixel of a one-dimensional or two-dimensional array of detector pixels. The detector elements can be, in particular, counting X-ray detectors that detect and count the incident individual X-ray quanta. Alternatively, it is also possible, for example, to use scintillator-based detector elements, where, for instance, a scintillator without afterglow or with a very short afterglow time can be used in conjunction with a silicon photomultiplier to achieve short readout times and good separation of the measurement data for different X-ray pulses.

[0010] Preferably, the data acquisition device is set up or synchronized to the control device in such a way that the writing of the measurement data or the processing data into the buffer memory for the respective X-ray pulse is completed before the next X-ray pulse is emitted.

[0011] The number of X-ray sources can be determined primarily by the number of projection geometries to be acquired. For example, 15-30 X-ray sources, and thus projection geometries, may be sufficient for a tomosynthesis application, while several hundred, or even 1000 or more projection geometries, and thus X-ray sources, may be used for computed tomography. Within the control pattern, each X-ray source can be controlled, for example, more than 100 times, more than 500 times, or approximately 1000 times, to emit a single X-ray pulse. This reduces the duration of each individual X-ray pulse and thus the exposure time of the respective X-ray source.

[0012] The X-ray source can include, in particular, a rigid anode and / or a field-effect transmitter, for example, based on nanotubes. A rigid anode is an anode that is fixed relative to the cathode and, in particular, does not rotate. Rigid anodes can be considerably smaller and simpler in design than rotating anodes. Practical results are achieved, for example, even with electric focal spot sizes of approximately 10 mm. 2 reached.

[0013] As will be explained in more detail later, preprocessing of the data from each individual detector element can take place within the detector element itself or in its associated data acquisition unit. This is particularly useful for summing the measurement data for the different X-ray pulses from the same X-ray source. This results in essentially the same amount of data as would be generated by using a single, continuous X-ray pulse for the respective projection geometry. This avoids unnecessarily large data volumes and data transmission requirements between the detector elements and the control unit or evaluation unit.

[0014] The time synchronization of the detector element readout to the control pattern can, in principle, be achieved through self-synchronization, for example, by detecting measurement signal edges. Preferably, however, the control unit and the various detector elements are explicitly synchronized, for example, by a common clock signal or by the control unit controlling or triggering the detector elements.

[0015] The control device is preferably configured to control the respective X-ray source to emit a respective X-ray pulse with a pulse length of less than 300 µs or less than 100 µs or less than 10 µs and / or to control successive X-ray sources in the control pattern at a time interval of less than 300 µs or less than 100 µs or less than 10 µs.

[0016] As described above, progressively shorter pulse durations allow for the use of increasingly higher power levels, thereby reducing the overall required exposure time. By using separate buffer memories for each detector element, the time required to write the measurement data or processing data for each X-ray pulse can be minimized. This allows X-ray pulses for different X-ray sources to be emitted in rapid succession while still being separated at the detector level. This further reduces the required measurement time and / or improves the temporal resolution of the measurement.

[0017] The respective data acquisition device may be configured to store the measurement data assigned to the separate X-ray pulses or the processing data determined from the respective measurement data in separate storage areas of the buffer memory and, after completion of the control pattern, to link the measurement data and / or the processing data stored in the buffer memory and assigned to the respective X-ray source by means of an arithmetic operation in order to provide total data assigned to the respective X-ray source.

[0018] In the simplest case, the individual measurement or processing data are added together, for example, to add the photon numbers, charges, or intensities recorded for the separate X-ray pulses. Depending on the specific type of data acquisition, however, multiplication, division, or subtraction may also be appropriate.

[0019] By combining the measurement and processing data of all X-ray pulses from the same X-ray source, the overall data can essentially correspond to the result that would be expected when using a continuous, longer X-ray pulse of the same intensity. Combining the measurement and processing data into a single dataset significantly reduces the amount of data that needs to be transferred from the respective data acquisition device to a processing device or control unit. Therefore, communication paths and processing approaches designed for continuous X-ray pulses from individual X-ray sources can also be used with the alternating, pulse-based use of the individual X-ray sources according to the invention. Thus, the inventive method can be implemented with minimal effort.

[0020] Alternatively, the respective data acquisition device can be configured to store, for each X-ray source, the first measurement data assigned to the first X-ray pulse of the respective X-ray source in the control pattern, or processing data determined from the first measurement data, in one of the buffer memory storage areas assigned to the respective X-ray source, and to link, by means of an arithmetic operation, each subsequent measurement data assigned to an X-ray pulse of the respective X-ray source following the first X-ray pulse in the control pattern, or preliminary processing data determined from the subsequent measurement data, with the existing content of the buffer memory storage area assigned to the respective X-ray source, and to store the linking result as processing data in the buffer memory storage area assigned to the respective X-ray source.

[0021] The determination of further measurement data and the linking of the further measurement data or the respective further preliminary processing result with the previous content of the storage area of ​​the buffer memory assigned to the respective X-ray source can be repeated in particular for each X-ray pulse of the respective X-ray source after the first X-ray pulse.

[0022] After completion of the control pattern, the memory area assigned to each X-ray source contains total data for each source. This total data is derived from an arithmetic operation of all measurement data associated with the X-ray pulses of the respective source, or from their preliminary processing data. The resulting total data thus corresponds to the total data discussed above, which would result from a subsequent summarization of the measurement or processing data. Compared to the procedure described above, however, this method allows for the use of significantly smaller buffer memory. Furthermore, the subsequent data summarization described above can be advantageous in shifting the time required to summarize the measurement or processing data to an interval after the completion of the control pattern and thus after the measurement process, thereby potentially shortening the measurement duration.

[0023] The allocation of memory areas to the X-ray sources can also be dynamic for each execution of the control pattern. For example, when using a cyclic buffer memory, a pointer describing the position of the respective memory access may have different values ​​at the beginning of separate passes of the control pattern, which can lead to different allocations of memory areas to the X-ray sources.

[0024] The buffer memory can be configured as a cyclic buffer, in which a read and write position of the buffer memory is defined by a cyclic memory pointer. In this case, the data acquisition device can be configured to increment the memory pointer by a predetermined value both after storing the respective initial measurement data or the processing data derived from it, and after storing the respective combination result, wherein the cycle length of the cyclic memory pointer corresponds to the product of the predetermined value and the number of X-ray sources.

[0025] In other words, the cycle length of the cyclic memory pointer is chosen such that, when using n X-ray sources, the memory pointer always points to the same memory cell or buffer address after n storage operations. If the X-ray sources are thus repeatedly activated in a fixed sequence, the described cycle length of the cyclic memory pointer ensures that, during the acquisition of the respective measurement data, the memory pointer always points to the memory area assigned to the X-ray source last used to emit an X-ray pulse. The memory pointer can therefore be used both to read the previous contents of the memory area assigned to the respective X-ray source and to store the result of the conversion. This allows for a particularly simple and robust synchronization of data acquisition with the emission of the X-ray pulses.

[0026] However, the use of a cyclic buffer memory can also be advantageous if the measurement or processing data for the individual X-ray pulses are initially written to separate memory areas of the buffer memory and only combined for transmission after completion of the control pattern, or even transmitted separately to an evaluation unit. In this case, the buffer memory should be sufficiently large so that data acquired within the control pattern is not overwritten within the same control pattern, but only at a later time, for example, during subsequent data acquisition when another control pattern is played.

[0027] The respective detector element is preferably formed by a photon-counting X-ray detector or by a specific pixel of a spatially resolved photon-counting X-ray detector comprising several or all of the detector elements. Photon-counting X-ray detectors, or their pixels, enable the detection and counting of individual incoming photons and thus exhibit, in particular, sufficient temporal resolution to acquire well-separated measurement data for each individual X-ray pulse, even with very short X-ray pulses. In this case, the measurement data can, in particular, indicate the respective number of photons detected by the respective detector element since the emission of the respective X-ray pulse.

[0028] As an alternative to a photon-counting X-ray detector, a detector with a scintillator that has no afterglow or a sufficiently short afterglow time could be used. In this case, sufficiently fast readout can be achieved, for example, by using a silicon photomultiplier.

[0029] The X-ray source can consist of a stationary anode and / or a cathode formed by a field-effect emitter. Using a field-effect emitter as the cathode allows for rapid activation and deactivation of electron emission, resulting in short X-ray pulses. For example, field-effect emitters based on carbon nanotubes can be used.

[0030] By alternating the use of different X-ray sources, they can cool down between the emission of individual X-ray pulses. Therefore, high X-ray power can be achieved even with a stationary anode. The device according to the invention can thus provide high X-ray power with minimal technical effort and therefore at low cost.

[0031] The device according to the invention can, for example, be a computed tomography scanner or a tomosynthesis system for imaging at least one area of ​​a patient during medical imaging. Although the described device, as already explained, can also be configured, for example, for materials testing or as a baggage scanner, the described embodiment is particularly advantageous in the field of medical imaging because short examination times not only improve the utilization of the device but also minimize artifact formation due to patient movement during imaging.

[0032] In a computed tomography (CT) scanner, the X-ray sources can be arranged in a 360° radius around the patient, for example, in one or more rings or in a helical arrangement. To achieve high spatial resolution, a CT scanner can use at least 500 or at least 1000 X-ray sources.

[0033] For a tomosynthesis system, a linear arrangement of X-ray sources or an arrangement spanning a certain solid angle segment of, for example, at least 40° or at least 60° may suffice. For tomosynthesis applications, 15-25 X-ray sources may be sufficient. For example, the tomosynthesis system can be used for breast tomosynthesis.

[0034] In particular, at least two of the X-ray sources can be spaced more than 30 cm, 50 cm, or 1 m apart. Additionally or alternatively, the X-ray sources can be arranged over an angular range of at least 15°, 30°, 60°, or 90° with respect to an isocenter of the imaging. The X-ray sources can, in particular, be arranged at equal distances or angular intervals from one another.

[0035] The problematic arrangement of the X-ray sources, or rather their distribution over a certain angular range, results in different imaging geometries depending on which X-ray source emits the respective X-ray pulse. Therefore, using separate X-ray sources that are activated sequentially serves not only to increase power output but also to provide different imaging geometries.

[0036] In addition to the device according to the invention, the invention also relates to a method for X-ray imaging by means of a device with several X-ray sources and an X-ray detector with at least one detector element, wherein the various X-ray sources are alternately controlled one after the other according to a predetermined control pattern to emit a respective X-ray pulse, so that the respective X-ray source emits several X-ray pulses within the framework of the control pattern, wherein, synchronously to the control pattern, respective measurement data of the respective detector element or processing data determined from the respective measurement data are repeatedly written into a buffer memory assigned to the respective detector element, so that the respective measurement data relate to X-ray radiation that is incident on the respective detector element due to a respective X-ray pulse that is assigned to the measurement data.

[0037] The method according to the invention can be implemented in particular by the device according to the invention. Regardless, features disclosed for the device according to the invention, with the advantages mentioned therein, can be transferred to the method according to the invention and vice versa.

[0038] The invention also relates to a computer program with instructions designed to carry out the method according to the invention when implemented on a device with multiple X-ray sources and an X-ray detector with at least one detector element.

[0039] Furthermore, the invention relates to a data carrier comprising the computer program according to the invention. The computer program according to the invention, or the data carrier according to the invention, can be further developed with the features and advantages described in connection with the method or device according to the invention, and vice versa.

[0040] Further advantages and details of the invention will become apparent from the following exemplary embodiments and the accompanying drawings. These schematically illustrate: Fig. 1 an embodiment of a device according to the invention for X-ray imaging, and Fig. 2 a flowchart of an embodiment of the inventive method for X-ray imaging.

[0041] Fig. Figure 1 shows a device 1 for X-ray imaging, comprising several X-ray sources 2 to 8 and an X-ray detector 9 with several detector elements 10 to 19, or pixels. In this example, the device 1 is a tomosynthesis system in which the X-ray sources 2-8 are distributed over an angular range 40 of approximately 70° with respect to an isocenter 41 of the imaging and are thus arranged at a relatively large distance 39 from each other. As already explained in the general section, tomosynthesis imaging would also be possible with a distribution of the X-ray sources over a narrower angular range, for example, 15°. For the sake of clarity, only 7 X-ray sources 2-8 and 10 detector elements 10 to 19 are shown in the example. In a real-world implementation, tomosynthesis systems typically use 15-30 X-ray sources and a large number of pixels or detector elements, for example, an array of 256 × 256 detector elements.

[0042] In an alternative configuration, a computed tomography scanner for static computed tomography could be provided by distributing the X-ray sources 2 to 8 around the entire patient 38, for example in several rings or along a helix.

[0043] By irradiating the patient 38 through the various X-ray sources 2 to 8 and capturing the respective image data by the X-ray detector 9, projection images from different perspectives result, from which, for example by the control unit 20 of the device 1 or by a separate evaluation unit not shown, three-dimensional image data can be reconstructed in a known manner.

[0044] When using distributed X-ray sources, fixed anodes (rigid anodes) are generally preferred for reasons of space and cost. As explained in the general section of this description, rigid anodes, when using a standard measurement protocol in which a continuous X-ray pulse is applied to the patient (38), the duration of which is chosen to achieve a sufficient X-ray dose at the detector, result in relatively long measurement times due to the limitation of the permissible power input to the anode. This makes certain types of measurements impossible or at least results in a significant risk of measurement interference from motion artifacts.

[0045] To enable the use of higher X-ray power and thus shorter exposure times, a modified procedure is used in the device 1. Here, the control unit 20 alternately controls the various X-ray sources 2 to 8 according to a predefined control pattern to emit a respective X-ray pulse 21, so that each X-ray source 2 to 8 emits several time-spaced X-ray pulses 21 within the control pattern. Instead of one long, continuous X-ray pulse, several short X-ray pulses from each X-ray source 2 to 8 are used, with X-ray pulses being emitted by the other X-ray sources 2 to 8 during the pauses between the operation of each X-ray source 2 to 8, during which each X-ray source 2 to 8 cools down.

[0046] To enable the separation of measurement data for the different X-ray pulses, a separate buffer memory 22 and a separate data acquisition unit 23 are used for each of the detector elements 10 to 19. The data acquisition unit 23 is configured to repeatedly write the respective measurement data 24 of the assigned detector element 10 to 19, or processing data 42 derived from these, into the assigned buffer memory 22, synchronously with the control pattern.

[0047] Time synchronization can be achieved, for example, by a common clock signal for the control unit 20 and the data acquisition units 23, or by direct control of the data acquisition units 23 by the control unit, for example by means of a trigger signal. This, and the use of relatively fast-switching X-ray sources 2 to 8, for example by using a field-effect transmitter as a cathode, ensures that the respective measurement data 24 correspond to the X-ray radiation incident on the respective detector element 10 to 19 due to each of the X-ray pulses 21 assigned to the measurement data 24.

[0048] For example, it is assumed that the detector elements 10 to 19 are photon-counting X-ray detectors, whereby the respective measurement data 24 represents the number of photons detected at each detector element 10 to 19 since the beginning of the emission of the last emitted X-ray pulse.

[0049] By using sufficiently short X-ray pulses, for example with a pulse length of less than 10 µs, high X-ray power can also be used with standing anodes, thus achieving an overall short measurement time.

[0050] An exemplary method for X-ray imaging implemented by device 1 is described below with reference to the method described in Fig.The flowchart shown in Figure 2 explains this in more detail. Steps S1 to S4 are performed once for each of the X-ray pulses 21 to be emitted. After each of these cycles, in step S6 or S8, as will be explained in more detail later, the X-ray source 2 to 8 used to emit the respective X-ray pulse 21 is changed, so that the X-ray sources 2 to 8 are alternately controlled according to a predefined control pattern, with each of the X-ray sources 2 to 8 being controlled multiple times to emit a respective X-ray pulse 21.

[0051] In step S1, in each iteration of steps S1 to S4, the currently selected X-ray source 2 to 8 is activated by the control unit 20 to emit a short X-ray pulse 21. In the first iteration of steps S1 to S4, the first X-ray source 2 is activated in step S1, the second X-ray source 3 in the next iteration, and so on. From the eighth iteration onward, i.e., after the activation of the seventh X-ray source 8, the preceding sequence is repeated, i.e., first the first X-ray source 2, then the second X-ray source 3, and so on.

[0052] In step S2, for each of the detector elements 10 to 19, the measurement data 24, i.e. in the example the number of X-ray photons detected since the beginning of the X-ray pulse, are read out from the respective detector element 10 to 19 by the respective data acquisition device 23.

[0053] For the first measurement data 33 acquired during the first seven iterations of steps S1 to S4, which are each assigned to a first X-ray pulse 21 of the respective X-ray source 2 to 9 in the control pattern, the respective first measurement data 33 are written directly in step S3 into a storage area 25 to 31 of the respective buffer memory 22 assigned to the respective X-ray source 2 to 8.

[0054] In the example, this is achieved by writing to a memory address specified by a cyclic memory pointer 37, whereby the memory pointer 37 is incremented by a specified value in the subsequent step S4, i.e. after the respective write operation, in order to select the memory area 25 to 31 assigned to the next of the X-ray sources 2-8.

[0055] In step S5, it is checked whether the last X-ray source 8 is currently selected and has therefore already emitted an X-ray pulse 21. If this is not the case, the next of the X-ray sources 2-8 is selected in step S6 and the procedure is repeated from step S1.

[0056] If, however, the last X-ray source 8 emitted the X-ray pulse 21, then in step S7 it is checked whether the individual X-ray sources 2 to 8 have already emitted a sufficient number of X-ray pulses 21. If this is not the case, then in step S8 the first X-ray source 2 is selected again and the procedure is continued from step S1 to emit another X-ray pulse 21 by this X-ray source 2.

[0057] After the seventh iteration of steps S1 to S4, the respective memory area 25 to 31 of the respective buffer memory 22 thus contains the respective first measurement data 33 relating to the first X-ray pulse 21 of the respective X-ray source 2 to 8. In this example, the cycle length of the memory pointer 37 is chosen such that it corresponds to the product of the specified value of the increment in step S4 and the number of X-ray sources 2 to 8. Therefore, the seventh increment of the memory pointer 37, after writing the first measurement data 33 for the first X-ray pulse 21 of the seventh X-ray source 8 in the seventh iteration of step S4, causes the memory pointer 37 to point again to the respective memory area 25 assigned to the first X-ray source 2.

[0058] From the eighth repetition of steps S1 to S4 onwards, the additional measurement data 34 previously acquired in step 2 are not written directly to the respective memory areas 25 to 31 in step S3. Instead, they are added to the existing content 35 of the memory areas 25 to 31 of the buffer memory 22 assigned to the respective X-ray source 2 to 8. The result of this addition 36 is then written as processing data 42 to the respective memory areas 25 to 31. The memory area for reading and writing is selected by the memory pointer 37.

[0059] The described procedure results in all measurement results 24 of the respective detector elements 10 to 19, which are assigned to the various X-ray pulses 21 of the same X-ray source 2 to 8, being added together. Thus, after completion of the control pattern, i.e., when it is recognized in step S7 that all X-ray pulses 21 to be emitted have already been emitted, the content 35 of the memory area 25 to 31 assigned to the respective X-ray source 2 to 8 can be made available in step S9 as total data 32 for the respective X-ray source. The total data can therefore essentially correspond to the data that would have been acquired if a continuous, long X-ray pulse had been emitted by the respective X-ray source 2 to 8.

[0060] The example discussed above assumes that the addition, or more generally the arithmetic operation, of the various measurement data 24 for pulses from the same X-ray source 2 to 8 takes place directly during data acquisition. Alternatively, however, it would be possible to use a larger buffer memory 22 in which each of the X-ray pulses 21 emitted by the various X-ray sources 2 to 8 is assigned a corresponding storage area in which the measurement data 24 associated with that X-ray pulse 21 can be stored. In this case, after completion of the control pattern, the measurement data 24 stored in the buffer memory 22 and assigned to the respective X-ray source 2 to 8 can be combined with each other by an arithmetic operation, i.e., added, to provide the total data 32 assigned to the respective X-ray source 2 to 8.

[0061] Alternatively, it would also be possible to transmit the measurement data 24, or the respective processing data derived from them and stored in the buffer memory 22, separately to the control unit 20 or a separate evaluation unit. However, the previously described summarization of measurement data 24 from different X-ray pulses 21 of the same X-ray source 2 to 8 can be advantageous in order to minimize the transmission time or the required transmission bandwidth.

[0062] The described method or device can be implemented, in particular, by executing a suitable computer program through the device 1. The instructions of the computer program can be executed, in particular, partly on the control unit 20 and partly on the individual data acquisition units 23.

[0063] Regardless of the grammatical gender of a particular term, persons with male, female or other gender identities are included.

Claims

[1] Device for X-ray imaging, comprising several X-ray sources (2-8), an X-ray detector (9) with at least one detector element (10-19) and a control device (20), characterized by, that the control device (20) is configured to alternately control the various X-ray sources (2-8) one after the other according to a predetermined control pattern to emit a respective X-ray pulse (21), such that the respective X-ray source (2-8) emits several X-ray pulses (21) within the framework of the control pattern, wherein a respective buffer memory (22) and a respective data acquisition device (23) are assigned to the respective detector element (10-19), wherein the data acquisition device (23) is configured to repeatedly write respective measurement data (24) of the assigned detector element (10-19) or processing data (42) determined from the respective measurement data (24) into the assigned buffer memory (22) synchronously with the control pattern, such that the respective measurement data (24) relate to X-ray radiation which is emitted due to a respective X-ray pulse (21) assigned to the measurement data (24),on the respective detector element (10-19). [2] Device according to claim 1, characterized by , that the control device (20) is configured to control the respective X-ray source (2-8) to emit a respective X-ray pulse (21) with a pulse length of less than 300 µs or less than 100 µs or less than 10 µs and / or to control successive X-ray sources (2-8) in the control pattern successively at a time interval of less than 300 µs or less than 100 µs or less than 10 µs. [3] Device according to claim 1 or 2, characterized by , that the respective data collection device (23) is set up to, - to store the measurement data (24) assigned to the separate X-ray pulses (21) or the processing data (42) determined from the respective measurement data (24) in separate storage areas (25-31) of the buffer memory (22) and - after completion of the control pattern, to link the measurement data (24) and / or the processing data (42) stored in the buffer memory (22) and assigned to the respective X-ray source (2-8) by means of an arithmetic operation in order to provide total data (32) assigned to the respective X-ray source (2-8). [4] Device according to claim 1 or 2, characterized by , that the respective data acquisition device (23) is set up to provide data for a respective X-ray source (2-8) - to store the respective first measurement data (33) assigned to the respective first X-ray pulse (21) of the respective X-ray source (2-9) in the control pattern, or processing data (42) determined from the first measurement data (33) in one of the storage areas (25-31) of the buffer memory (22) assigned to the respective X-ray source (2-8) and - to link the respective further measurement data (34) that are assigned to an X-ray pulse (21) of the respective X-ray source (2-8) following the first X-ray pulse (21) in the control pattern, or preliminary processing data determined from the further measurement data (2-8) by an arithmetic operation with the previous content (35) of the storage area (25-31) of the buffer memory (22) assigned to the respective X-ray source (2-8) and to store the linking result (36) as processing data (42) in the storage area (25-31) of the buffer memory (22) assigned to the respective X-ray source (2-8). [5] Device according to claim 4, characterized by, that the buffer memory (22) is designed as a cyclic buffer, wherein a read and write position of the buffer memory (22) is specified by a cyclic memory pointer (37), wherein the data acquisition device (23) is configured to increase the memory pointer (37) by a predetermined value both after storing the respective first measurement data (33) or the processing data (42) determined from these, and after storing the respective linking result (34), wherein the cycle length of the cyclic memory pointer (37) corresponds to the product of the predetermined value and the number of X-ray sources (2-8). [6] Device according to one of the preceding claims, characterized by , that the respective detector element (10-19) is formed by a photon-counting X-ray detector or a respective pixel of a spatially resolved photon-counting X-ray detector forming several or all of the detector elements (10-19). [7] Device according to one of the preceding claims, characterized by , that the respective X-ray source (2-8) comprises a stationary anode and / or a cathode formed by a field-effect emitter. [8] Device according to any of the preceding claims, characterized by , that it is a computed tomography scanner or a tomosynthesis system for imaging at least one area of ​​examination of a patient (38) in the context of medical imaging. [9] Device according to any of the preceding claims, characterized by , that at least two of the X-ray sources (2-8) are spaced (39) apart from each other by more than 30 cm or more than 50 cm or more than 1 m and / or that the X-ray sources (2-8) are distributed over an angular range (40) of at least 15° or at least 30° or at least 60° or at least 90° with respect to an isocenter (41) of the imaging. [10] Method for X-ray imaging by a device (1) with several X-ray sources (2-8) and an X-ray detector (9) with at least one detector element (10-19), characterized by , that the various X-ray sources (10-19) are alternately and successively controlled according to a predetermined control pattern to emit a respective X-ray pulse (21), so that the respective X-ray source (2-8) emits several X-ray pulses (21) within the framework of the control pattern, whereby, synchronously to the control pattern, respective measurement data (24) of the respective detector element (10-19) or processing data (42) determined from the respective measurement data (24) are repeatedly written into a buffer memory (22) assigned to the respective detector element (10-19), so that the respective measurement data (24) relate to X-ray radiation which is incident on the respective detector element (10-19) due to a respective X-ray pulse (21) which is assigned to the measurement data (24). [11] Computer program with instructions configured to carry out the method according to claim 10 when implemented on a device (1) with multiple X-ray sources (2-8) and an X-ray detector (9) with at least one detector element (10-19). [12] Data carrier comprising a computer program according to claim 11.

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