Method for operating an x-ray device, x-ray device, computer program and electronically readable data carrier

Abstract

The invention relates to a method for operating an X-ray device having an X-ray emitter device with an X-ray emitter for emitting an X-ray field for examining an examination object and having an X-ray detector for receiving X-ray radiation of an X-ray field, wherein the X-ray radiation device has a single slot for the X-ray radiation device, which has a housing in which a radiation exit window for the X-ray radiation generated by the X-ray radiation device and a radiation shaping device for setting a desired extent and position of the X-ray field are arranged, and wherein deviation information is ascertained by means of a control device of the X-ray device, the deviation information describes a deviation of an actual extension and position of the X-ray field from a desired position and extension of the X-ray field due to a temperature situation in the X-ray emitter device, and the radiation shaping device is controlled in accordance with the deviation information in order to at least partially compensate for the deviation.

Description

Field of the Invention

[0001] The present invention relates to a method for operating an X-ray device having an X-ray radiator device and an X-ray detector, the X-ray radiator device having an X-ray radiator for emitting an X-ray field for examining an examination object, the X-ray detector for receiving the X-ray radiation of the X-ray field, wherein the X-ray radiator device has:

[0002] - a single tank for the X-ray radiator, the single tank having a housing in which a radiation exit window for the X-ray radiation generated by the X-ray radiator is provided, and - a ray shaping device for setting the desired extent and position of the X-ray field.

[0003] The present invention also relates to an X-ray device, a computer program, and an electronically readable data carrier. Background Art

[0004] An X-ray device for imaging examinations of patients typically has an X-ray radiator for generating X-ray radiation. In order to provide an X-ray field of a desired position and extent, the X-ray radiator is usually associated with a ray shaping device, which can be implemented as part of the X-ray radiator device together with the X-ray radiator. Such a ray shaping device can be, for example, a collimator and / or an aperture device. If the X-ray radiator is accommodated, for example, in a single tank, the single tank usually has a housing filled with a circulating cooling medium, in which the X-ray radiator is also provided, and the X-ray radiator outputs X-ray radiation through the radiation exit window of the housing. Then, the ray shaping device can be fastened, in particular flange-connected, to the single tank, especially in its own additional housing. Then, it is arranged such that the aperture (usually also called a sheet) of the ray shaping device acts on the X-rays as desired and an X-ray field of the desired extent and position is generated according to the setting of the ray shaping device.

[0005] In an X-ray device for mammography (mammography device), the breast to be recorded as an examination object is supported, for example, directly or indirectly on the X-ray detector and appropriately compressed via a so-called "paddle", i.e., a compression plate, while the patient is directly at a holding device surrounding the compression plate and the X-ray detector. In this case, the ray shaping device can include a front aperture (front sheet) and a rear aperture (rear sheet), where the aperture facing the patient is called the front aperture and the aperture facing away from the patient is called the rear aperture. By correspondingly controlling the ray shaping device, i.e., by positioning the aperture, the X-ray field is adjusted such that as much of the entire breast as possible is recorded, yet in an ideal case, the radiation towards the patient misses the X-ray detector as little as possible. For example, boundary values can be set in this regard.

[0006] When operating an X-ray radiator by means of a corresponding electric power, heating of the X-ray radiator occurs. If the X-ray radiator is configured, for example, as an X-ray tube having a rotating anode supported in a vacuum by means of a bearing device, power is also required for the drive device of the rotating anode, which may cause further heating. This may in turn cause the rotating anode together with the focal track to move relative to the entire X-ray device, such that movement of the focal spot, i.e., the focus, relative to the beam shaping device and / or relative to the X-ray detector may also occur. Secondary effects, such as heating of the single-slot housing, may also play an important role. In a vacuum-supported rotating anode that is not directly attached to the coolant, the effect is particularly strong because the rotating anode and the bearing device may dissipate heat into the cooling medium in the single-slot only poorly.

[0007] Generally, therefore, due to thermal effects, movement of the X-ray field occurs, and thus movement of the irradiated area occurs. Therefore, during the examination operation, the field of view can change, such that in order to completely record an examination object, such as a breast, it is necessary to make settings in terms of extension and position using a certain safety buffer. However, X-ray radiation that occurs outside the area to be actually imaged and recorded is undesirable, for example, when there is a required maximum overexposure length, and this is disadvantageous, especially when this required maximum overexposure length is reached or even exceeded, for example, in mammography towards the patient's breast. Summary of the Invention

[0008] Therefore, the object of the present invention is to reliably apply X-ray radiation in a actually desired field of view.

[0009] According to the present invention, the object is achieved by a method, an X-ray device, a computer program, and an electronically readable data carrier according to the present invention, which are particularly computer-implemented. Advantageous improvements are described below.

[0010] In a method of the type described at the beginning, according to the present invention, it is proposed that by means of a control device of the X-ray device

[0011] - Obtain deviation information that describes the deviation of the actual extension and position of the X-ray field from the desired position and extension of the X-ray field caused by the temperature situation in the X-ray device, and

[0012] - Control the beam shaping device according to the deviation information to at least partially compensate for the deviation.

[0013] It is thus proposed to determine directly or indirectly, in particular to measure or estimate, the temperature effects causing deviations, and / or to directly determine the deviations. The corresponding deviation information is then used to readjust the beam shaping device accordingly and to obtain as precisely as possible the desired extension and position of the X-ray field, in particular to limit the X-ray field to the detection surface of the X-ray detector.

[0014] In particular and preferably, the deviation information relates here to important temperature conditions, in particular important temperatures, within the X-ray radiator, which can be measured and / or estimated due to the known use of the X-ray radiator. The temperature information available as deviation information, in particular at least one temperature value, can then be used, for example, to calculate the position of the focal point, in particular the focal spot, relative to the X-ray detector and relative to the beam shaping device and to readjust the beam shaping device accordingly. In this case, as will be described in more detail below, it is not necessary to directly perform an explicit calculation of the position of the focal point, but it is also possible to use a deviation model that directly outputs the deviation or the necessary correction measures.

[0015] In this way, it is achieved that safety buffers that may be too high due to thermal effects in the X-ray radiator device are largely or completely dispensed with, so that on the one hand, in particular, the actual desired area can be recorded and on the other hand, no unwanted X-ray radiation, in particular X-ray radiation that does not reach the X-ray detector, is generated. Thus, the radiation load on the patient and / or other persons present can be reduced. No additional X-ray dose is administered due to a wrongly set X-ray field.

[0016] The application of the method according to the invention is particularly advantageous when an X-ray tube with a rotating anode rotatably arranged in a vacuum via a support device is used as the X-ray radiator. Such a rotating anode is not directly attached to a coolant such as oil and can thus heat up together with its support device, which can cause significant position changes, in particular displacements, of the rotating anode, and thus significant position changes, in particular displacements, of the focal track and the actual focal spot. In this case, for example, the temperature of the rotating anode and / or its support device can be regarded as an important temperature, which, however, can also be determined indirectly, for example via the temperature in a single tank.

[0017] In an advantageous first design of the present invention, it can be proposed that at least a part of the deviation information is measured by means of at least one temperature sensor of the X-ray device. In this case, for example, additional temperatures at locations where the temperature cannot be directly measured can also be derived from the measured temperature distribution in a single slot as part of the deviation information. However, it is particularly expedient and enables precise compensation measures to be determined when important temperatures can be directly measured. In the case of an X-ray tube with a rotatable anode arranged in a vacuum, in a specific design of the present invention, it can be proposed, for example, that at least one temperature sensor, which is particularly configured as an infrared sensor, measures the temperature of the rotatable anode and / or the carrier device. If the temperature sensor is configured as an infrared sensor, the infrared sensor does not have to be directly arranged at the rotatable anode and / or the carrier device, but can be directed at the rotatable anode and / or the carrier device in order to detect the corresponding temperature.

[0018] Furthermore, in an advantageous embodiment, it can be proposed that at least a part of the deviation information describes and / or is derived from the heating power and / or the cooling period of the X-ray radiator. Since it is known in a control device, for example a corresponding recording unit for controlling a recording run, when the X-ray radiator is operating, and thus when the drive device for the X-ray radiation and / or the rotatable anode is in operation, the power introduced correspondingly and the power period during which the power is introduced are also known and can be used as deviation information and / or for the determination of the deviation information. Particularly advantageously, a power profile is determined which not only indicates when (and ideally where) the electrical power for operating the X-ray radiator is introduced, but also when the cooling period is between these phases of introducing the electrical power. The power introduced and the cooling period located in between mainly determine the temperature behavior of the X-ray radiator. Therefore, an expedient improvement at this point proposes that the current temperature of the X-ray radiator, in particular the rotatable anode and / or its carrier device, is determined as deviation information on the basis of a temperature model which describes the heating and cooling behavior of the X-ray radiator, based on the power and the cooling period. For example, when it comes to estimating the possible number of patients in an X-ray device, temperature models which also describe the cooling during the cooling period are already known from other applications of X-ray radiators, in particular X-ray tubes, from the prior art. A temperature model which not only describes the heating during power input but also the cooling in the absence of power input and thus allows the current temperature to be understood as an estimate can be used expediently in order to continuously and in real time track the temperature situation in the X-ray radiator as deviation information.

[0019] In a specific design approach of the present invention, it can be proposed that deviation information is used as input data for a deviation model, and the deviation model provides at least one correction measure as output data, and the ray shaping device is controlled according to the correction measure. Such a deviation model can in principle be an analytical model, which, for example, allows the determination of the movement of the focal point relative to the desired position of the focal point as an internal intermediate result and correspondingly generates a correction measure in order to derive the resulting deviation between the current extension and position of the X-ray field and the desired extension and position of the X-ray field through this movement. However, the deviation model can also be at least partially empirical, whether this concerns the movement of the focal point or directly concerns the correction measure.

[0020] Generally speaking, the deviation model provides the association between the deviation information and the correction measure to be executed, i.e., the readjustment. Therefore, the deviation model can, for example, include the relationship between at least one important temperature and the readjustment path of at least one aperture. In this case, especially in an empirical relationship where a function can be matched with the correction data recorded during the calibration process to be discussed later, the temperature value does not necessarily directly form the input data, but can also start from the power that indirectly derives the temperature situation, especially the power curve with a cooling period and similar variables. In particular, in principle, it is also conceivable that the deviation model includes at least one trained function trained by machine learning. Such a trained function can, for example, include a neural network, especially a CNN, and is trained according to the correction data as the training data.

[0021] Therefore, during the calibration process, the values of the deviation information and the associated values of the deviation can be recorded, so that the correction measures can be recorded and used to appropriately adjust the deviation model. Therefore, it can be proposed that at least one parameter of the deviation model is determined during the calibration process, in which the deviations of different thermal states of the X-ray device described by the corresponding deviation information are measured. Here, the calibration can be obtained either across the X-ray device, for example, for the type or model of the X-ray device, especially by using measurements at multiple different X-ray devices; however, it is also feasible to perform a calibration specific to a particular X-ray device. Specifically, there are multiple feasibilities for measuring the displayed deviation.

[0022] Here, particularly advantageously, the measurement of the deviation relates to the position of at least one aperture of the beam shaping device, as in the case of X-ray radiation imaging. This position of the aperture is the boundary of the X-ray field. If it is now known where the aperture and thus the boundary of the X-ray field should actually be located, then it is possible to implement the actual position of the aperture or the boundary of the X-ray field in the X-ray radiator device, in particular in the X-ray radiator, for a plurality of different thermal states, i.e., temperature situations, in order to obtain suitable correction data. For this purpose, in principle, it is possible to consider using an external measuring device; however, preferably, an X-ray detector and / or a measuring device forming part of the X-ray device is used.

[0023] In summary, therefore, it is possible to propose that, in order to determine the deviation, the at least one measured position of the aperture of the beam shaping device (and thus the boundary of the X-ray field) is compared with the desired position according to the control of the beam shaping device, in order to measure the deviation. Preferably, an X-ray detector and / or a measuring device fixedly installed in the X-ray device is used as the measuring mechanism for the calibration process.

[0024] Specifically, for example, it can be proposed that, in the absence of a patient, the aperture is set such that its shadow falls on the X-ray detector, so that the boundary of the X-ray field is detected by the X-ray detector. Then, the desired position and the actually measured position for different thermal states can be measured in order to determine the deviation by comparison. It is also feasible that a measuring device is arranged laterally in a manner connected to the X-ray detector, and with the aid of this measuring device, the deviation extending beyond the X-ray detector can also be measured and determined in the case where the aperture is set on the edge of the X-ray detector. This additional measuring device preferably can have a plurality of measuring chambers in order to obtain spatial resolution.

[0025] In some cases, it is also possible to actually measure the deviation during the inspection run of the X-ray device and use it to update the deviation model. Thus, for example, it can be considered that, in order to update the deviation model during the inspection run, at least one measuring device connected to the X-ray detector on one side of the X-ray detector is used, and / or the X-ray detector is used to determine the orientation of the boundary of the X-ray field (and thus the measured position of the aperture) when the examination object does not cover the entire X-ray detector. If the entire X-ray detector is not required, for example in mammography in the case of small breasts, the unnecessary portion of the X-ray detector can be blocked by the aperture of the beam shaping device. If it is now determined that the blocking does not take place as desired, i.e., the measured position of the boundary of the X-ray field does not correspond to the desired position, then the deviation is determined, which can be associated with the current thermal state of the X-ray device described by the deviation information. If the X-ray detector is generally used in its entirety in most cases, the X-ray field is usually also used in such a way that the X-ray detector is fully utilized, so that it can be expedient to use a fixedly mounted, additional measuring device in order to be able to measure the current position of the boundary of the X-ray field also beyond the extent of the X-ray detector, wherein the measuring device is connected to the X-ray detector at least on one side. In order to provide spatial resolution, such a measuring device can, for example, have a plurality of measuring chambers succeeding one another in the extension direction, the predetermined extent of which is the same. In this way, the measuring device can be simply maintained, but still provide position resolution.

[0026] However, in other embodiments of the present invention, it is also feasible to directly measure at least a part of the deviation and use it to derive a correction measure. Then it can be proposed that at least a part of the deviation information, as the deviation of the orientation of the boundary of the X-ray field from the desired position and the desired position of the desired extension of the X-ray field, is measured by means of an X-ray detector or a measuring device connected to the X-ray detector on one side of the X-ray detector or the measuring device. For example, if the X-ray field is set such that the X-ray field should completely cover the X-ray detector, more precisely its detection surface, in the desired extension and position, but an occlusion is determined on one side in the recorded X-ray image, then there is a (measured) deviation here, which can be taken into account for another, subsequent X-ray recording. If the deviation moves to the other side, then a measuring device connected to the X-ray detector, as already described, can be expedient in order to measure the deviation, especially in a design with a plurality of measuring chambers in the direction in which the measuring device is connected to the X-ray detector. This is especially expedient in the context of mammography applications, because, for example, measurements can then be made on the "back" side, i.e., away from the patient, and correction measures for the "front" side, i.e., towards the patient, can be derived therefrom. If there is no symmetry, then, for example, a ray set can be used to determine the deviation of the other side of the X-ray detector and thus also the associated correction measures. However, since this "on the fly" correction requires a first uncompensated image recording, it is less preferred.

[0027] Generally, the method described here can also be applied particularly advantageously in mammography. Thus, a mammography device can be used as an X-ray device, where the ray shaping device has a front aperture facing the patient and a rear aperture facing away from the patient, and where the position of the front aperture is adjusted at least by manipulating the ray shaping device to compensate for deviations. The front aperture is usually also referred to as the front sheet or the front film here, and the rear aperture is correspondingly referred to as the rear sheet. Precisely in mammography, deviations on the front side, i.e., small deviations towards the patient, can also be extremely important, such that compensation here is particularly advantageous. If the X-ray field is deviated towards the patient, then radiation that is not used for imaging may be introduced into the patient, which is undesirable. In this context, the maximum overexposure length already mentioned can also be present as a preset, for example. On the other hand, if the front boundary of the X-ray field moves away from the patient, then the breast may no longer be detected completely, which is also undesirable. Since deviations in the range of a few millimeters due to thermal effects have been observed, these deviations are of course important and can be used particularly advantageously in the field of mammography according to the method of the present invention.

[0028] In addition to the method described above, the present invention also relates to an X-ray device having an X-ray radiator device and an X-ray detector, the X-ray radiator device having an X-ray radiator for emitting an X-ray field for examining an examination object, the X-ray detector being used for receiving the X-ray radiation of the X-ray field, wherein the X-ray radiator device has:

[0029] - a single slot for the X-ray radiator, the single slot having a housing in which a radiation exit window for the X-ray radiation generated by the X-ray radiator is provided, and - a ray shaping device for setting the desired extension and position of the X-ray field, wherein the X-ray device further has a control device, the control device including:

[0030] - an obtaining unit for obtaining deviation information, the deviation information describing the deviation of the actual extension and position of the X-ray field from the desired position and extension of the X-ray field caused by the temperature condition in the X-ray radiator device, and

[0031] - a compensation unit for controlling the ray shaping device according to the deviation information to at least partially compensate for the deviation.

[0032] In other words, the control device is configured to execute the method according to the present invention. All embodiments of the method according to the present invention can be similarly transferred to the X-ray device according to the present invention and vice versa, so that the advantages mentioned above can also be obtained by using the X-ray device.

[0033] In particular, the X-ray device can, for example, have at least one temperature sensor and / or at least one measuring device, the measuring device being connected to the X-ray detector in one direction. The control device can include at least one processor and at least one storage mechanism, and has functional units formed by hardware and / or software, the functional units including an obtaining unit and a compensation unit. The control device can also have other functional units, whether they are functional units known in principle such as a recording unit for controlling the recording operation or functional units for implementing advantageous designs of the method according to the present invention. The latter functional units can, for example, include a temperature model unit for applying a temperature model and / or a deviation model unit for applying a deviation model.

[0034] A computer program according to the present invention can be directly loaded into the storage mechanism of the control device of an X-ray apparatus and has a program mechanism which, when the computer program is executed on the control device, causes the control device to perform the steps of the method according to the present invention. The computer program can be stored on an electronically readable data carrier according to the present invention, which data carrier thus includes control information stored thereon, the control information including at least one computer program according to the present invention and being designed such that when the data carrier is used in the control device of an X-ray apparatus, the data carrier constitutes means for performing the method according to the present invention. The data carrier can in particular be a non-transitory data carrier, such as a CD-ROM. BRIEF DESCRIPTION OF THE DRAWINGS

[0035] Other advantages and details of the present invention result from the embodiments described below and from the drawings. Shown here are:

[0036] Figure 1 A schematic diagram showing the principle of an X-ray apparatus according to the present invention,

[0037] Figure 2 A schematic diagram showing the problem on which the present invention is based,

[0038] Figure 3 A diagram showing the arrangement of an object to be examined for image recording,

[0039] Figure 4 A schematic diagram showing the use of a measuring device for illustration,

[0040] Figure 5 A flowchart showing an embodiment of the method according to the present invention, and

[0041] Figure 6 A diagram showing the functional structure of the control device of an X-ray apparatus. DETAILED DESCRIPTION OF THE INVENTION

[0042] Figure 1 An X-ray apparatus 1 according to the present invention is schematically shown, which X-ray apparatus 1 is currently configured as a mammography apparatus. In the following embodiments, the present invention will be discussed with regard to its application in a mammography environment.

[0043] The X-ray apparatus 1 includes an X-ray radiator device 2, which is held on a support 3 and, in addition to a single slot 4 in which an X-ray radiator 5 is provided, also includes a ray shaping device 6, currently a collimator. By means of a radiation exit window, which is not shown in detail here, in the housing of the single slot 4 and which faces, for example, the ray shaping device 6 connected by a flange, and the ray shaping device 6, an X-ray field with a desired extension and position with respect to the X-ray detector 7 can be generated. Above the X-ray detector 7, there is a compression plate 8 ("flap"), and the X-ray detector 7 also serves as a support for the breast to be recorded as the examination object. The operation of the X-ray apparatus 1 is controlled by a control device 9.

[0044] Figure 2 The construction of the X-ray radiator device 2 in important components is shown in more detail, and the problem on which the present invention is based is explained. The X-ray radiator 5 provided in the housing 10 of the single slot 4 is configured as an X-ray tube, which has a rotating anode 11. The rotating anode 11 is currently held in a vacuum via a bearing device 12 and can be rotated via a drive device 13. An electron beam emitted from an electron source 14, which is only schematically represented, strikes the focal track of the rotating rotating anode 11 and is converted into X-ray radiation there, and the X-ray radiation is emitted through a radiation exit window 15, for example, a locally thinned part of the material of the housing 10. The ray shaping device 6 includes a front, i.e., patient-facing, and thus outwardly disposed from the plane of the figure in [[]] Figure 1 a movable aperture 16 and a rear aperture 17, and the front aperture and the rear aperture can also be referred to as a front sheet and a rear sheet, for example.

[0045] If the ray shaping device 6 is set to the desired extension and position of the X-ray field, then the rotating anode 11 is in the position shown by the solid line relative to the ray shaping device 6 and relative to the X-ray detector 7, which is represented here by the detector face 18. At this position, the X-ray that just forms the front boundary of the X-ray field and can still pass through the front aperture 16 is shown as an arrow 19. Due to the thermal effect, depending on the temperature situation, i.e., the thermal state, the rotating anode 11 can be moved to the moved position 20 shown by the dashed line, so that the relative position with respect to the ray shaping device 6 and with respect to the X-ray detector 7 is changed. This causes: the boundary of the X-ray field, which is again represented by the edge-side ray as an arrow 21, also changes, so that a deviation 22 from the desired orientation of the boundary of the X-ray field is produced according to the desired extension and position, which is not desired. Therefore, the method described here has the following purpose: to analyze the thermal state of the X-ray radiator 5 and to determine at least one correction measure in order to at least partially compensate for the deviation. The correction measure for the front aperture 16 is in [[]] Figure 2This is indicated by arrow 23, and if necessary, corresponding correction measures can also be determined for the rear aperture 17.

[0046] Figure 3 The situation in mammography is described in detail again. A patient 24 with a breast 25 to be examined is shown, where the compression plate 8 is not shown for the sake of overview. The X-ray field 26 that is optimal for this situation is shown, and the X-ray field currently precisely includes the breast 25 and the X-ray detector 7, specifically its detector surface 18. If the rotating electrode 11 now moves due to the thermal effect, the front boundary 27 of the X-ray field 26 is particularly important because movement in both directions is not desired here. Movement of the boundary 27 forward, i.e., towards the patient 24, misses the detector 7 and is an unnecessary radiation load. Movement of the boundary 27 backward, i.e., away from the patient 24, results in the breast 25 no longer being fully imaged. Therefore, the correction measures currently at least include correspondingly adjusting the position of the front aperture 16.

[0047] Figure 3 The feasibility of how to obtain additional information about the rear boundary 28 of the X-ray field 26 in the measurement environment, especially when the breast is small or for correcting the deviation model (which will be discussed in more detail below), is also shown. Similar to the front boundary 27 of the front aperture 16, the rear boundary corresponds to the shadow projection of the rear aperture 17. If at this time, a measuring device 29 is connected to the X-ray detector 7 in the continuation of the detector surface 18 of the detector 7, and the measuring device 7 can include a plurality of measuring chambers 30, for example, to generate spatial resolution, then due to the measuring chambers 30 being correspondingly loaded with X-ray radiation, the movement of the rear boundary 28 in the backward direction can also be understood.

[0048] Figure 4 An example of making a measurement at the rear edge of the X-ray detector 7 is shown, where in the case of a forward deviation from the desired boundary 28, the shadow projection, i.e., the deviated boundary 28', can be recognized on the X-ray detector 7, and in the case of a backward movement, i.e., the deviated boundary 28'', the measuring chambers 30 can be loaded with X-ray radiation to show the movement. In particular, in mammography, it can be considered that the correction method according to the present invention is implemented as follows: by means of the X-ray detector 7 and optionally by means of the measuring device 29, the deviation of the orientation of the rear boundary 28 from the desired orientation due to the thermal effect is measured by the X-ray detector 7 and / or another measuring device 29, and the necessary correction measures for the front aperture 16 are correspondingly determined from this in the case of using the asymmetry of the ray set.

[0049] Figure 5A flowchart showing another embodiment of the method according to the present invention is presented. Therein, in step S1, deviation information is obtained, which currently describes the temperature situation in the X-ray radiator device 2 in the form of at least one estimated and / or measured temperature, specifically for the temperature situation of the rotating anode 11 and its carrier device 12, i.e., the thermal state of the important components of the X-ray radiator 5. In this case, on the one hand, it is feasible that the temperature of the rotating anode 11 and / or the carrier device 12 and optionally additional temperatures are measured via corresponding temperature sensors 31 (see Figure 2 ), where infrared temperature sensors 31 are preferably used within the X-ray radiator 5. However, it is also feasible to derive it from other temperature measurements; alternatively or preferably additionally, the temperature can also be derived from the known usage of the X-ray radiator 5 in the control device 9. For this purpose, a power profile is provided, which describes the power output for operating the electron source 14 and the drive device 13 during a power time period and the cooling time periods between said power time periods. The estimated current temperature of the rotating anode 11 and / or the carrier device 12 can be obtained therefrom by means of a temperature model and used as deviation information.

[0050] In step S2, the deviation information, specifically the temperature, is passed as input data to a deviation model, which provides a deviation that can be directly converted into a correction measure as output data and / or directly provides a correction measure. In this case, it can relate to an empirical, pre-calibrated deviation model, but it can also relate to an analytical deviation model, which, for example, can first calculate the shifted position of the focal point and can derive the deviation and the necessary correction measures therefrom.

[0051] As already mentioned, the correction measure does not necessarily relate to all deviations from the boundaries 27, 28, but can, for example, only relate to the front aperture 16 in mammography.

[0052] In order to calibrate such a deviation model, i.e., to determine at least one parameter of the deviation model, a calibration process can be performed. In this case, it is feasible that, in the absence of an examination object, for example, using only the X-ray detector 7, but also optionally using a measuring device 29, for different thermal states described by the deviation information, the actually occurring deviations are measured, for example, as the deviation of the orientation of the boundaries 27, 28 from the desired orientation. The obtained calibration data (where the deviation information is associated with the actual deviation) can be used for the correct parameterization of the deviation model, for example, for fitting the function of the deviation model and / or for training the function of the machine learning deviation model. If it is feasible to measure the deviation during the examination run, then the deviation can be used for further optimization / credibility check of the result of the deviation model.

[0053] Then, in step S3, the correction measures derived from the output data of the deviation model are correspondingly executed in such a way that the control device correspondingly controls the ray forming device 6.

[0054] Finally, Figure 6 The functional structure of the control device 9 is shown in connection therewith. In addition to the usual functional units not shown here, such as the recording unit, the control device first has an obtaining unit 32 in which deviation information is obtained according to step S1. For this purpose, the obtaining unit 32 can cooperate with an optional temperature model unit 33 which evaluates the power change curve and provides the estimated current temperature.

[0055] In the deviation model unit 34, the deviation model can be applied according to step S2. Finally, in the compensation unit 35, the corresponding correction measures are executed according to step S3.

[0056] The control device 9 additionally also has a storage mechanism 36 in which, for example, the temperature model and the deviation model can be stored.

[0057] It should also be noted at this point that the control device preferably can directly and automatically execute the correction measures. However, of course, the following embodiment can also be considered, in which the calibration measures are first provided to the user as correction feasibility for confirmation.

[0058] Although the details of the present invention have been described in detail by means of the preferred embodiments, the present invention is not limited by the disclosed examples and other variants can be derived therefrom by those skilled in the art without departing from the protection scope of the present invention.

[0059] Regardless of the grammatical gender of the specific terms, persons with male or female identities are included.

Claims

1. A method for operating an X-ray device (1), the X-ray device (1) having an X-ray radiator device (2) and an X-ray detector (7), the X-ray radiator device having an X-ray radiator (5) for emitting an X-ray field (26) for examining an examination object, the X-ray detector for receiving X-ray radiation from the X-ray field (26), the X-ray radiator device (2) having: a single slot (4) for the X-ray radiator (5), the single slot having a housing (10) in which a radiation exit window (15) for the X-ray radiation generated by the X-ray radiator (5) is arranged, and - a beam shaping device (6) for setting the desired extension and position of the X-ray field (26), It is characterized in that By means of a control device (9) of the X-ray device (1) - determining deviation information which describes a deviation (22) of the actual extension and position of the X-ray field (26) from an expected position and extension of the X-ray field (26) due to temperature conditions in the X-ray radiator arrangement (2), and - controlling the beam shaping device (6) based on the deviation information to at least partially compensate for the deviation (22).

2. The method according to claim 1, characterized in that An X-ray tube having a rotating anode (11) is used as an X-ray radiator (5), which is rotatably arranged in a vacuum via a carrier device (12).

3. The method according to claim 1 or 2, characterized in that: At least a portion of the deviation information is measured by means of at least one temperature sensor (31) of the x-ray radiator arrangement (2).

4. The method according to claims 2 and 3, characterized in that The at least one temperature sensor (31), in particular designed as an infrared sensor, measures the temperature of the rotating anode (11) and / or the carrier device (12).

5. The method according to any one of the preceding claims, characterized in that At least part of the deviation information describes a heat-generating power and / or a cooling time period of the x-ray emitter (5) and / or at least part of the deviation information is ascertained from the variable.

6. The method according to claim 5, characterized in that The current temperature of the X-ray radiator (5), in particular the rotating anode (11) and / or its support device (12), is determined as deviation information based on the power and the cooling time period using a temperature model that describes the heating and cooling behavior of the X-ray radiator (5).

7. The method according to any one of the preceding claims, characterized in that The deviation information is used as input data for a deviation model which provides at least one corrective measure as output data, according to which the beam shaping device (6) is actuated.

8. The method according to claim 7, characterized in that At least one parameter of the deviation model is ascertained during a calibration process in which deviations of different thermal states of the x-ray radiator arrangement (2) are measured, the different thermal states being described by corresponding deviation information.

9. The method according to claim 8, characterized in that The X-ray detector (7) is used as a measuring device for the calibration process and / or at least one measured position of an aperture (16, 17) of the beam shaping device (6) is compared with a desired position based on the control of the beam shaping device (6) to determine the deviation.

10. The method according to any one of claims 7 to 9, characterized in that In order to update the deviation model during an examination run, at least one measuring device (29) connected to the X-ray detector (7) on one side of the X-ray detector (7) is used, and / or the X-ray detector (7) is used to determine the orientation of the boundaries (27, 28) of the X-ray field (26) when the examination object does not cover the entire X-ray detector (7).

11. The method according to any one of the preceding claims, characterized in that At least part of the deviation information is measured by means of the X-ray detector (7) or one or the measuring device (29) connected to the X-ray detector (7) on one side of the X-ray detector (7) as a deviation of the orientation of the boundary (27, 28) of the X-ray field (26) from an expected orientation according to an expected extension and position of the X-ray field (26).

12. The method according to any one of the preceding claims, characterized in that A mammographic X-ray device (1) is used as an X-ray device, in which the radiation shaping device (6) has a front aperture (16, 17) arranged toward a patient (24) and a rear aperture (16, 17) arranged away from the patient (24), wherein by manipulating the radiation shaping device (6), at least the position of the front aperture (16) is adjusted to compensate for the deviation.

13. An X-ray device (1) comprising an X-ray radiator device (2) having an X-ray radiator (5) for emitting an X-ray field (26) for examining an object to be examined, and an X-ray detector (7) for receiving X-ray radiation from the X-ray field (26), wherein the X-ray radiator device (2) has: a single slot (4) for the X-ray radiator (5), the single slot having a housing (10) in which a radiation exit window (15) for the X-ray radiation generated by the X-ray radiator (5) is arranged, and - a beam shaping device (6) for setting the desired extension and position of the X-ray field (26), It is characterized in that The X-ray device (1) further comprises a control device (9), wherein the control device (9) comprises: a determination unit (32) for determining deviation information describing a deviation of the actual extension and position of the X-ray field (26) from an expected position and extension of the X-ray field (26) due to temperature conditions in the X-ray radiator arrangement (2), and - a compensation unit (35) for controlling the beam shaping device (6) based on the deviation information to at least partially compensate for the deviation.

14. A computer program which, when executed on a control device (9) of an X-ray device (1), causes the control device to execute the steps of the method according to any one of claims 1 to 12.

15. An electronically readable data carrier on which a computer program according to claim 14 is stored.

Images