EP4723808A1

EP4723808A1 - X-ray tube temperature supervision

Info

Publication number: EP4723808A1
Application number: EP24204152.3A
Authority: EP
Inventors: Joachim Lieber; Ruth WIEBUS; Alexander MANDELIK STERN; Christian Herbert BLOME
Original assignee: Koninklijke Philips NV
Current assignee: Koninklijke Philips NV
Priority date: 2024-10-02
Filing date: 2024-10-02
Publication date: 2026-04-08
Also published as: WO2026073750A1

Abstract

A temperature supervisor (10) for an X-ray tube comprises a processor (12) configured to: receive tube operational data (16) during use of the X-ray tube in an X-ray imaging system, wherein the tube operational data comprises a voltage and/or current and/or power applied to the X-ray tube; process the received tube operational data to determine a present temperature of a component of the X-ray tube; receive mechanical load data (18) during use of the X-ray tube, wherein the mechanical load data relates to a present mechanical load on the component. In accordance with the invention, the mechanical load data is used to determine a present temperature limit for the component, wherein the present temperature limit is dynamic and dependent on the present mechanical load on the component. The determined present temperature of the component is compared with the determined present temperature limit of the component to output an alarm signal (21) for alerting a user and/or a safety control signal (22) for controlling operation of the X-ray tube, if the determined present temperature of the component is higher than the determined present temperature limit of the component. The temperature supervisor (10) provides safety in combination with high-performance utilization of the X-ray tube in that the dynamic temperature limit depends on the mechanical load on the X-ray tube component and therefore allows to take co-dependency between mechanical load and maximum thermal load into account.

Description

FIELD OF THE INVENTION

The invention relates to a temperature supervisor for monitoring a thermal behavior of an X-ray tube, a high voltage generator, an X-ray imaging system, a computer-implemented method for supervising the temperature of an X-ray tube, a computer program element, and a computer-readable medium.

BACKGROUND OF THE INVENTION

X-ray imaging is an important imaging modality in medical and other applications. X-ray sources like X-ray tubes are used to generate X-ray radiation that passes through a subject and impinges on an X-ray detector. The X-ray tube typically includes a cathode with a filament and an anode. When a filament current is applied to the filament, the filament current heats the filament, causing the filament to expel electrons (thermionic emission), creating a space charge a short distance away from the filament. A peak X-ray tube voltage is applied across the cathode and the anode, and causes a beam of the electrons to accelerate from the cathode and impinge the anode. The X-ray tube current, or emission current, represents the number of electrons per second flowing from the cathode to the anode. Electrostatic or magnetic focusing with e.g. grid electrodes or quadrupoles can be applied to control a size of and steer the beam of electrons. An interaction of the electrons with the material of the anode produces heat and radiation, including X-rays, which pass through a tube window, into an examination region, to the X-ray detector.
Only a small fraction of electrical energy applied to an X-ray tube used in combination with a high voltage generator, is converted into useful radiation. Most of the electric power is converted into thermal energy. Thermal safety measures are applied to stop operation of the X-ray tube if the temperature of the X-ray tube becomes too high. However, such safety measures may be insufficient and/or may limit full utilization of the X-ray tube.

SUMMARY OF THE INVENTION

It is an object of the invention to provide an improved performance and safe operation of the X-ray tube.
The invention is defined by the independent claims. Advantageous embodiments are defined in the dependent claims.
According to a first aspect of the invention, there is provided a temperature supervisor for monitoring a thermal behavior of an X-ray tube during use. The tube temperature supervisor comprises a processor configured to:

receive tube operational data during use of the X-ray tube in an X-ray imaging system, wherein the tube operational data comprises a voltage and/or current and/or power applied to operate the X-ray tube;
process the received tube operational data to determine a present temperature of a component of the X-ray tube; and
receive mechanical load data during use of the X-ray tube, wherein the mechanical load data relates to a present mechanical load on the component.

process the mechanical load data to determine a present temperature limit for the component, wherein the present temperature limit is dynamic and dependent on the present mechanical load on the component;
compare the determined present temperature of the component with the determined present temperature limit of the component; and
output an alarm signal for alerting a user and/or a safety control signal for controlling operation of the X-ray tube, if the determined present temperature of the component is higher than the determined present temperature limit of the component.

The temperature supervisor may thus provide for safety in combination with high-performance utilization of the X-ray tube. In accordance with the invention, the dynamic temperature limit depends on the mechanical load on the X-ray tube component and therefore allows to take co-dependency between mechanical load and maximum thermal load into account. When the mechanical load on the component increases, the maximum allowed thermal load may be reduced and vice versa, in order to provide for improved safety and performance.
The tube operational data may include an X-ray tube voltage, an emission current, the X-ray tube power (product of voltage and current), filament current etc. These parameters may be applied by and/or determined by a high voltage generator for driving the X-ray tube. The tube operational data may be received from the high voltage generator.
Processing of the tube operational data to determine a present temperature of a component may include inputting the operational data into a computational model and/or a look-up table with data comprising pre-generated output of such a model. The computational model may simulate thermal behavior of the X-ray tube. Such a model may form a digital twin of the X-ray tube. The computational model may comprise a trained neural network.
The mechanical load data may comprise a motion parameter, such as a parameter describing motion of the X-ray tube or one of its components. Such motion influences the mechanical load on the component of the X-ray tube. E.g. an acceleration or deceleration may increase or decrease the physical stress on the component. Alternatively, or additionally, the mechanical load data may comprise a pressure parameter and/or a strain parameter. Changes to the mechanical load may change the maximum thermal load on the component for safe operation. The mechanical load data may be received from the X-ray imaging system, such as from a controller of the X-ray imaging system.
Similarly to the tube operational data, processing of the mechanical load data to determine a present dynamic temperature limit may include inputting the mechanical load data into a computational model and/or a look-up table with data comprising pre-generated output of such a model. The computational model may simulate thermal and/or mechanical load of the X-ray tube. Such a model may form a digital twin of the X-ray tube or the X-ray imaging system. The computational model may comprise a trained neural network.
The temperature supervisor comprises a processor, such as but not limited to a computer, a (local or remote) computer network, and/or another programmable apparatus, such as a single and/or multi core processing unit, a graphics processing unit, an accelerated processing unit, a digital signal processor, a field programmable gate array, an application-specific integrated circuit, etc. The processor may comprise or otherwise interact with a memory for storing data, long term and/or short term.
The alarm signal may be output to a user interface, such as to a user interface of the X-ray imaging system. The user interface may, based on the alarm signal, generate an audio, visual and/or tactile alarm signal to notify a user. The safety control signal may be output to e.g. the high voltage generator or to an X-ray imaging system controller. Operation of the X-ray tube may be stopped or otherwise adapted based on the safety control signal, such that a potentially unsafe situation is avoided. The safety control signal may trigger a change in at least one of e.g. an X-ray tube (peak) voltage, an emission current, a gantry rotation speed, a focal spot movement, a detection period, or a detection frequency
According to an embodiment, the mechanical load data comprises a present movement parameter, descriptive of a movement the X-ray tube with respect to a stationary part of the X-ray imaging system. The movement parameter may include at least one of a velocity, a speed, a position coordinate, or an acceleration. The present movement parameter may be descriptive of a rotational movement of a gantry of the X-ray imaging system, a tilting of the X-ray tube in the X-ray imaging system, a lateral movement of the X-ray tube, such as when part of the system is moving on rails, and/or a movement of a C-arm of the X-ray imaging system.
Taking movement of the X-ray tube into account for the determination of the dynamic temperature limit improves temperature supervision, since such motion may have a significant impact on the mechanical load on components of the tube. Mechanical load data relating to the X-ray tube movement may be received from the X-ray imaging system, e.g. from a controller or user interface of the X-ray imaging system. During execution of an imaging application with the X-ray system, movements of the X-ray tube may be pre-planned, such as with known time-stamps. The mechanical load data may comprise such time stamps for variations in planned motion of the X-ray tube.
According to an embodiment, the component is an X-ray tube bearing, such as a liquid metal bearing. As is further elaborated on in the detailed description, optimal or maximal thermal load on the X-ray tube bearing, particularly on a hydrodynamic bearing (liquid metal bearing) may be closely intertwined with the current mechanical load on the same component. Hence, the improved temperature supervisor may be particularly advantageous in this case.
According to an embodiment, the safety control signal is a signal for controlling an anode rotation speed. Since anode rotation speed may influence thermal behavior of the X-ray tube as well as mechanical load on (and/or load bearing capacity of) components such as the bearing and rotational system, adapting the anode rotation speed may be an effective way to ensure safe and efficient operation of the X-ray tube
According to an embodiment, the processor is further configured to receive a sensor signal from a temperature sensor, and to adapt the determined present temperature of the component and/or the determined present temperature limit based on the sensor signal. Including data from a temperature sensor may further improve the accuracy of determining the present temperature and/or temperature limit of the X-ray tube component.
According to an embodiment, the temperature supervisor comprises the temperature sensor, and the temperature sensor is located externally from the X-ray tube. Due to the high voltage environment and high vacuum of the X-ray tube, providing a temperature sensor outside of the X-ray tube, and preferably outside of an X-ray tube housing surrounding the X-ray tube, is advantageous in order to reduce complexity and cost.
According to an embodiment, the temperature sensor is configured to measure a temperature ambient to the X-ray tube. The ambient temperature sensor may be configured to measure the temperature of the air surrounding an X-ray tube assembly, such as air in a gantry of the X-ray system or in the room where the X-ray system is placed.
According to an embodiment, the temperature sensor is configured to measure an X-ray tube oil temperature. Oil may be used with X-ray tubes to provide cooling and/or electrical insulation of the tube. The oil temperature sensor may be integrated into a path for pumping oil to or from the X-ray tube during operation.
According to a second aspect of the invention, there is provided a high voltage generator comprising the temperature supervisor of the first aspect.
According to a third aspect of the invention, there is provided an X-ray imaging system, comprising an X-ray tube and the high voltage generator of the second aspect. The X-ray imaging system may be e.g. a diagnostic X-ray imaging system, a computed tomography system, an X-ray imaging system for interventional guidance such as with a C-arm, an X-ray imaging system for security applications, etc.
According to a fourth aspect of the invention, there is provided a computer-implemented method for supervising the temperature of an X-ray tube during use, the method comprising:

receiving tube operational data during use of the X-ray tube in an X-ray imaging system;
processing the received tube operational data to determine a present temperature of a component of the X-ray tube;
receiving mechanical load data during use of the X-ray tube, wherein the mechanical load data relates to a present mechanical load on the component;
processing the mechanical load data to determine a present temperature limit for the component, wherein the present temperature limit is dynamic and dependent on the present mechanical load on the component;
comparing the determined present temperature of the component with the determined present temperature limit of the component; and
outputting an alarm signal for alerting a user and/or a safety control signal for controlling the X-ray tube, if the determined present temperature of the component is higher than the determined present temperature limit of the component.

According to a fifth aspect of the invention, there is provided a computer program element, which, when being executed by a tube temperature supervisor comprising a processor, is adapted to cause the tube temperature supervisor to perform the method according to the fourth aspect.
According to a sixth aspect of the invention, there is provided a computer-readable medium having stored thereon the computer program element of the fifth aspect.
These and other aspects of the invention will be apparent from and elucidated with reference to the embodiments described hereinafter.

BRIEF DESCRIPTION OF THE DRAWINGS

Fig. 1 schematically illustrates a temperature supervisor for monitoring a thermal behavior of an X-ray tube.
Fig. 2 schematically illustrates an X-ray imaging system.
Fig. 3 shows an example of a temperature limit curve.
Fig. 4 schematically illustrates a computer-implemented method for supervising the temperature of an X-ray tube.

DESCRIPTION OF EMBODIMENTS

Computer models or other data processing may be used to monitor the thermal behavior of an X-ray tube or its components during imaging with an X-ray imaging system. To prevent thermal overloading of the X-ray tube, operation of the tube may be stopped if a limit, such as a bearing temperature limit, is surpassed. However, the inventors have found that due to co-dependency of different parameters of the X-ray tube and the X-ray imaging system, such monitoring may lead to the X-ray imaging system not fully utilizing the potential performance of the tube. The present disclosure therefore proposes a dynamic temperature limit to achieve a safe and high-performance utilization of the X-ray tube.
Fig. 1 schematically illustrates an example of a temperature supervisor 10 for monitoring a thermal behavior of an X-ray tube. The temperature supervisor 10 comprises a processor 12. The processor 12 may be a computer, a computer network, and/or another programmable apparatus, such as a single and/or multi core processing unit, a graphics processing unit, an accelerated processing unit, a digital signal processor, a field programmable gate array, an application-specific integrated circuit, etc. In the example in Fig. 1, the temperature supervisor comprises a memory 14 for storing data, long term and/or short term.
The processor 12 is configured to receive tube operational data 16 during use of the X-ray tube in an X-ray imaging system. The tube operational data provides information about the current operation of the X-ray tube and comprises a voltage and/or current and/or power applied to operate the X-ray tube. The tube operational data 16 may include an X-ray tube voltage, an emission current, the X-ray tube power (product of voltage and current), filament current etc. The tube operational data 16 may be received from a high voltage generator driving the operation of the X-ray tube. The processor 12 is configured to process the received tube operational data to determine a present temperature of a component of the X-ray tube. E.g., the tube operational data may be used to determine a present temperature of a bearing in a rotational system of the X-ray tube. The present temperature of the component may be determined by inputting the operational data into a computational model, and/or to a look-up table with data comprising pre-generated output of such a model. The computational model may simulate thermal behavior of the X-ray tube. Such a model may form a digital twin of the X-ray tube. The computational model may comprise a trained neural network. The computational model and/or look-up table may be stored in a memory 14 locally or remotely from the processor.
The processor 12 is configured to receive mechanical load data 18 during use of the X-ray tube. The mechanical load data 18 relates to a present mechanical load on the component and may comprise a parameter describing motion of the X-ray tube or one of its components. Such motion influences the mechanical load on the component of the X-ray tube. E.g. an acceleration or deceleration may increase or decrease the physical stress on the component. The mechanical load data 18 may comprise a present movement parameter, which indicates a movement of the X-ray tube with respect to a stationary part of the X-ray imaging system. Such as an acceleration, a velocity, a speed of movement, a change in position coordinates etc. The present movement may be a rotational movement of a gantry of the X-ray imaging system, a tilting motion of the X-ray tube in the X-ray imaging system, a movement of a C-arm of the X-ray imaging system etc. Alternatively, or additionally to a motion parameter, the mechanical load data may comprise a pressure parameter and/or a strain parameter.
Changes to the mechanical load may change the maximum thermal load that the particular component can withstand for safe operation. As illustrated in more detail in Fig. 2 below, the mechanical load data 18 may be received from the X-ray imaging system, such as from a controller of the X-ray imaging system. The processor 12 is configured to process the mechanical load data 18 to determine a present temperature limit for the component. The present temperature limit is dynamic and dependent on the present mechanical load on the component. Processing of the mechanical load data to determine a present dynamic temperature limit may include inputting the mechanical load data 18 into a computational model and/or a look-up table with data comprising pre-generated output of such a model. The computational model may simulate thermal and/or mechanical load of the X-ray tube. Such a model may form a digital twin of the X-ray tube or the X-ray imaging system. The computational model may comprise a trained neural network.
The processor 12 is further configured to compare the determined present temperature of the component with the determined present temperature limit of the component. If the present temperature of the component is higher than the corresponding temperature limit, the processor 12 outputs an alarm signal 21 for alerting a user and/or outputs a safety control signal 22 for controlling operation of the X-ray tube. The alarm signal 21 may be output to a user interface, such as to a user interface of the X-ray imaging system. The user interface may generate an audio, visual and/or tactile alarm signal to notify a user. The safety control signal 22 may be output to the high voltage generator or to an X-ray imaging system controller. Operation of the X-ray tube may be stopped or otherwise adapted based on the safety control signal 22, such that a potentially unsafe situation is avoided. The safety control signal 22 may be a signal for controlling an anode rotation speed of the X-ray tube. The anode rotation speed may directly influence thermal behavior of the X-ray tube and/or mechanical load on components.
Fig. 2 illustrates an example of an imaging system 200 including a temperature supervisor 10, such as the temperature supervisor 10 in Fig. 1. The imaging system 200 in Fig. 2, such as a computed tomography system, has a stationary part 202 and a rotating gantry 201. The rotating gantry 201 rotates around a bore in which an imaging subject 210 may be placed. The rotating gantry includes an X-ray tube 100 in an X-ray tube assembly. The X-ray tube is configured to generate X-rays that penetrate the examination region with the imaging subject 210. A detector 203 is located on the opposite side of the gantry to detect the X-ray radiation. A high voltage generator 50 for driving the X-ray tube is also located in the gantry. In this example, the temperature supervisor 10 is comprised in, and in direct contact with, the high voltage generator 50. The high voltage generator 50 is connected to a controller 205. The controller 205 is also connected to the detector 203 and an encoder 204 for determining the angular position of the X-ray tube 100 and detector 203. The rotating gantry 201 in Fig. 2 also includes a temperature sensor 60 connected to the high voltage generator 50. The temperature sensor 60 measures an ambient temperature in the gantry 201 and/or an oil temperature of the X-ray tube, such as the temperature of oil for cooling of the X-ray tube 100.
When the gantry 201 rotates, the X-ray tube 100 and its components experiences mechanical load from acceleration forces. With information about the mechanical load, e.g. from motion data including the rotational speed and/or acceleration of the gantry, the temperature supervisor 10 may determine a suitable dynamic temperature limit for the present conditions. The motion data may be communicated to the temperature supervisor 10 from the controller 205. Based on current operational parameters, e.g. from the high voltage generator 50, a present temperature of a component of the X-ray tube may be determined or estimated. The determination of the component temperature may be improved with input from the temperature sensor 60. By comparing the determined component temperature with the present dynamic temperature limit, the temperature supervisor 10 may determine if an action is required. E.g. if the component temperature is higher than the corresponding temperature limit, the temperature supervisor 10 may output a warning signal 21 for an operator of the system. Alternatively, or additionally, the temperature supervisor may generate a safety control signal 22. E.g. to the high voltage generator 50 and/or to the controller 205. The safety control signal 22 may trigger a change in operation of the X-ray tube 100 and/or system 200, such as a change in at least one of e.g. X-ray tube (peak) voltage, emission current, anode rotation speed, gantry rotation speed, focal spot movement, detection periods and frequency etc.
As an example, the temperature supervisor 10 may determine a dynamic temperature limit for a liquid metal bearing (hydrodynamic bearing) of the X-ray tube. Such a temperature limit for the liquid metal bearing may prevent failure of the bearing due to exceeding the load carrying capacity. At higher temperatures, the dynamic viscosity of the liquid metal is reduced. This leads to a reduced load carrying capacity. It is often advantageous to keep the bearing load carrying capacity above a certain threshold value for the bearing to work reliably.
An example of applying the relation between temperature and mechanical load into a dynamic temperature limitation is illustrated in Fig. 3Error! Reference source not found.. In this example, the dynamic temperature limit curve 300 of an X-ray tube component depends on the G-force at the X-ray tube component. E.g. in the case of a bearing of an X-ray tube in a rotating gantry. In a situation without further information about actual present gantry rotation speed, a temperature supervision model would assume the highest possible G-forces at the bearing. This means that the temperature during operation would be limited to a comparatively low temperature at all times, which may impose longer cool-down times and slow down workflows. On the other hand, as shown by the dynamic temperature limit curve 300, when using information about the actual gantry speed, i.e. information about the mechanical load as G-force on the bearing, much larger temperature limits may be permitted for (parts of) scans with lower G-forces. The temperature limit is a function of the centrifugal acceleration of the gantry. In this way, improved performance and safe operation of the component may be achieved over the entire range of loads.
Fig. 4 schematically shows an example of a computer-implemented method 400 for supervising the temperature of an X-ray tube during use. The method 400 may be carried out with a processor, such as with a tube temperature supervisor 10 comprising a processor 12. Embodiments of the tube temperature supervisor 10 may mutatis mutandis also be applicable to the method, and vice versa. The method 400 includes receiving 410 tube operational data 16 during use of the X-ray tube in an X-ray imaging system. The tube operational data 16 may be received from a high voltage generator driving the operation of the X-ray tube, from a controller of the imaging system, etc. The tube operational data 16 is processed 420 to determine a present temperature of a component of the X-ray tube. The component may be e.g. a bearing of the X-ray tube, such as a liquid metal bearing.
The method 400 further includes receiving 430 mechanical load data 18 during use of the X-ray tube. The mechanical load data 18 relates to a present mechanical load on the component and may be associated with forces from motion of the X-ray tube, such as acceleration forces from rotation in a gantry or with a C-arm. The mechanical load data 18 may comprise a pressure parameter and/or a strain parameter. The mechanical load data is processed 440 to determine a present temperature limit for the component. The determined present temperature limit is dynamic and dependent on the present mechanical load on the component. The method 400 may also include (not shown in Fig. 4) receiving a sensor signal from a temperature sensor, and to adapt the determined present temperature of the component and/or the determined present temperature limit based on the sensor signal. The additional information from a temperature sensor may increase the accuracy of the determination of the temperature of the component and/or a suitable temperature limit for the component under the present conditions. E.g. taking ambient temperature or temperature of other components into account.
The method further comprises comparing 450 the determined present temperature of the component with the determined present temperature limit of the component. In this way there is a check that the temperature of the component is within the allowed range for safe and/or high-performance operation. If the determined present temperature of the component is higher than the determined present temperature limit for the same component, an alarm signal 21 and/or a safety control signal 22 is output 460. The alarm signal 21 may be used to alert a user locally and/or remotely. The alarm signal may be, with appropriate hardware such as a suitable user interface, converted to a human perceivable signal such as an audio signal, a visual signal, a haptic signal etc. The safety control signal 22 may automatically trigger a change in operation of the X-ray tube, high voltage generator and/or the imaging system. Such as stopping current operation, changing operational parameters like tube voltage, emission current, filament current etc. The safety control signal 22 may trigger a stop or change of movement of the X-ray tube in the X-ray imaging system, such as by adapting a gantry rotation speed. The safety control signal 22 may trigger a change in anode rotation speed of the X-ray tube.
It should be noted that the above-mentioned embodiments illustrate rather than limit the invention, and that those skilled in the art will be able to design many alternative embodiments without departing from the scope of the appended claims. In the claims, any reference signs placed between parentheses shall not be construed as limiting the claim. The word "comprising" does not exclude the presence of elements or steps other than those listed in a claim. The word "a" or "an" preceding an element does not exclude the presence of a plurality of such elements. The invention may be implemented by means of hardware comprising several distinct elements, and/or by means of a suitably programmed processor. A computer program may be stored/distributed on a suitable medium, such as an optical storage medium or a solid-state medium supplied together with or as part of other hardware, but may also be distributed in other forms, such as via the Internet or other wired or wireless telecommunication systems. In the device claim enumerating several means, several of these means may be embodied by one and the same item of hardware. Measures recited in mutually different dependent claims may advantageously be used in combination.

REFERENCE SIGNS

10: Temperature supervisor
12: Processor
14: Memory
16: Tube operational data
18: Mechanical load data
21: Alarm signal
22: Safety control signal
50: HV Generator
60: Temperature sensor
100: X-ray tube
200: X-ray imaging system
201: Rotating gantry
202: Stationary part
203: Detector
204: Encoder
205: Controller
210: Imaging subject
300: Temperature limit curve
400: Method for supervising the temperature
410: Receiving tube operational data
420: Processing the tube operational data
430: Receiving mechanical load data
440: Processing the mechanical load data
450: Comparing temperature with temperature limit
460: Outputting if temperature is higher than limit

Claims

A temperature supervisor (10) for monitoring a thermal behavior of an X-ray tube during use, wherein the tube temperature supervisor comprises a processor (12) configured to:
receive tube operational data (16) during use of the X-ray tube in an X-ray imaging system, wherein the tube operational data comprises a voltage and/or current and/or power applied to operate the X-ray tube;

process the received tube operational data to determine a present temperature of a component of the X-ray tube;

receive mechanical load data (18) during use of the X-ray tube, wherein the mechanical load data relates to a present mechanical load on the component;

process the mechanical load data to determine a present temperature limit for the component, wherein the present temperature limit is dynamic and dependent on the present mechanical load on the component;

compare the determined present temperature of the component with the determined present temperature limit of the component; and

output an alarm signal (21) for alerting a user and/or a safety control signal (22) for controlling operation of the X-ray tube, if the determined present temperature of the component is higher than the determined present temperature limit of the component.
The temperature supervisor according to claim 1, wherein the mechanical load data (18) comprises a present movement parameter, wherein the present movement parameter is descriptive of a movement of the X-ray tube with respect to a stationary part of the X-ray imaging system.
The temperature supervisor according to claim 2, wherein the present movement parameter is descriptive of a rotation of a gantry of the X-ray imaging system, a tilting of the X-ray tube in the X-ray imaging system, a lateral movement of the X-ray tube, and/or a movement of a C-arm of the X-ray imaging system.
The temperature supervisor according to any of the preceding claims, wherein the component is an X-ray tube bearing, such as a liquid metal bearing.
The temperature supervisor according to any of the preceding claims, wherein the safety control signal is a signal for controlling an anode rotation speed.
The temperature supervisor according to any of the preceding claims, wherein the processor (12) is further configured to receive a sensor signal from a temperature sensor (60), and to adapt the determined present temperature of the component and/or the determined present temperature limit based on the sensor signal.
The temperature supervisor according to claim 6, wherein the temperature supervisor comprises the temperature sensor (60), and wherein the temperature sensor is located externally from the X-ray tube.
The temperature supervisor according to claim 7, wherein the temperature sensor (60) is configured to measure a temperature ambient to the X-ray tube.
The temperature supervisor according to claim 6 or 7 or 8, wherein the temperature sensor (60) is configured to measure an X-ray tube oil temperature.
A high voltage generator (50) comprising the temperature supervisor (10) according to any of the preceding claims.
An X-ray imaging system (200), comprising an X-ray tube (100) and the high voltage generator (50) according to claim 10.
A computer-implemented method for supervising the temperature of an X-ray tube during use, the method (400) comprising:
receiving (410) tube operational data (16) during use of the X-ray tube in an X-ray imaging system;

processing (420) the received tube operational data to determine a present temperature of a component of the X-ray tube;

receiving (430) mechanical load data (18) during use of the X-ray tube, wherein the mechanical load data relates to a present mechanical load on the component;

processing (440) the mechanical load data to determine a present temperature limit for the component, wherein the present temperature limit is dynamic and dependent on the present mechanical load on the component;

comparing (450) the determined present temperature of the component with the determined present temperature limit of the component; and

outputting (460) an alarm signal (21) for alerting a user and/or a safety control signal (22) for controlling the X-ray tube, if the determined present temperature of the component is higher than the determined present temperature limit of the component.
A computer program element, which, when being executed by a tube temperature supervisor comprising a processor, is adapted to cause the tube temperature supervisor to perform the method according to claim 12.
A computer-readable medium having stored thereon the computer program element of claim 13.