MONITORING THE STATE OF AN X-RAY TUBE

Abstract

Systems and methods are provided for monitoring the state of an x-ray tube (100). The method comprises: receiving sensor data from a sensor array apparatus (120) positioned to observe at least part of a surface of an anode (102) of the x-ray tube; processing the received sensor data to identify and quantify surface damage to the anode; storing the identified and quantified surface damage with a time stamp; and correlating the identified and quantified surface damage to one or more usage protocols in an operational history record of the x-ray tube and used at a time corresponding the time stamp and/or used at a time in between time stamps.

Claims

1. A method for monitoring the state of an x-ray tube, the method comprising: receiving sensor data from a sensor apparatus positioned to measure radiation from at least part of a surface of an anode of the x-ray tube; processing the received sensor data to identify and quantify surface damage to the anode; storing the identified and quantified surface damage with a time stamp; and correlating the identified and quantified surface damage to one or more usage protocols in an operational history record of the x-ray tube and used at a time corresponding the time stamp and/or used at a time in between time stamps.

2. The method of claim 1, wherein the correlating comprises determining severity of the surface damage per protocol for at least one of the usage protocols.

3. The method of claim 1, wherein the correlating comprises determining severity of the surface damage for at least one combination of the usage protocols.

4. The method of claim 1, wherein processing the received sensor data to identify surface damage to the anode comprises performing x-ray intensity monitoring using the received sensor data.

5. The method of claim 1, wherein processing the received sensor data to identify surface damage to the anode comprises performing x-ray spectral monitoring using the received sensor data.

6. The method of claim 1, further comprising identifying spatial asymmetry in anode aging.

7. The method of claim 1, wherein the processing of the received sensor data is performed in real-time, the method further comprising issuing a warning in response to the detection of an acute progression and/or an acute extent of the surface damage.

8. The method of claim 1, wherein the processing of the received sensor data is performed in real-time, the method further comprising detecting high voltage generator performance changes based on high and/or low intensity levels in the received sensor data.

9. The method of claim 8, wherein detecting high voltage generator performance changes further comprises identifying a close-to-arcing state of the high voltage generator based on the intensity levels.

10. The method of claim 1, comprising: implementing one or more tube-lifetime extension measures based on the monitored state of the x-ray tube.

11. The method of claim 10, wherein the one or more tube-lifetime extension measures comprise adapting one or more usage protocols, and wherein adapting one or more of the usage protocols comprises adapting a cooling cycle of the x-ray tube to prolong tube life.

12. The method of claim 10, wherein the one or more tube-lifetime extension measures comprise adapting one or more usage protocols, and wherein adapting one or more of the usage protocols comprises adapting one or more focal spot parameters to shift focal spot position away from the surface damage.

13. The method of claim 12, wherein adapting one or more focal spot parameters to shift focal spot position comprising shifting the focal spot to a position at which re-melting of the anode in the region of the surface damage is enabled.

14. A system for monitoring the state of an x-ray tube, comprising: a memory that stores a plurality of instructions; and a processor coupled to the memory and configured to execute the plurality of instructions to: receive sensor data from a sensor apparatus positioned to measure radiation from at least part of a surface of an anode of the x-ray tube; process the received sensor data to identify and quantify surface damage to the anode; store the identified and quantified surface damage with a time stamp; and correlate the identified and quantified surface damage to one or more usage protocols in an operational history record of the x-ray tube and used at a time corresponding the time stamp and/or used at a time in between time stamps.

15-18. (canceled)

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0035] A detailed description will now be given, by way of example only, with reference to the accompanying drawings, in which:

[0036] FIGS. 1A and 1B illustrate monitoring of the state of an x-ray tube;

[0037] FIGS. 2A and 2B illustrate spectrum modifications resulting from mechanical damage to the surface of an anode disk; and

[0038] FIG. 3 illustrates a computing device that can be used in accordance with the systems and methods disclosed herein.

DETAILED DESCRIPTION OF EMBODIMENTS

[0039] FIG. 1A illustrates an x-ray tube 100 comprising a rotating anode disk 102 having an x-ray focal spot or track area 104 which collects an electron beam 106 emitted by a cathode (not shown) and which emits part of an x-ray beam 108. The x-ray beam 108 passes through a pinhole camera 110 before arriving at a first linear detector array 112-1, creating thereby an image of the track area 104. FIG. 1A shows a sideview of the x-ray tube 100 along a direction perpendicular to an axis of rotation of the anode disk 102.

[0040] FIG. 1B is a view along a direction parallel to the rotation axis. As shown in FIG. 1B, a second linear detector array 112-2 is provided alongside the first, with a half-sided filter 116 being interposed between the second linear detector array 112-2 and the pinhole camera 110 to filter the x-ray beam 108, while the x-ray beam arriving at the first linear detector array 112-1 remains unfiltered. The pinhole camera 110, detector arrays 112-1, 112-2, and filter 116 form part of a sensor apparatus 120 for x-ray tube aging monitoring. The sensor apparatus 120 in this example monitors the spatial radial profile of the x-ray emission area. The first linear detector array 112-1 provides a measurement of the x-ray intensity distribution versus anode disk radius (i.e. along the cross section of the focal spot track) and can therefore monitor intensity changes during anode lifetime. Surface damage to the anode appears in form of modified intensities as compared to reference measurements for particular exposure settings. In addition, surface damage can be spectrally monitored by the second linear detector array 112-2 equipped with the filter 116 for filtration of the x-ray intensities. The two linear detector arrays thus form a 2N detector array 112, which monitors surface damage appearing as modified signal ratios of the two columns. The sensor apparatus 120 may be arranged within the tube 100 itself (for example within the tube housing, optionally with shielding e.g. a shield filter to minimize detector damage by high intensity radiation) or alternatively in the vicinity of a tube exit window (not shown). The sensor apparatus 120 is sufficiently compact to enable flexible use in different imaging system setups. In this example, the sensor apparatus 120 is mounted before the beam collimator, without blocking that part of the x-ray beam (not shown) which is emitted by the track area 104 and used for imaging.

[0041] In use, real-time sensor data acquired by the sensor apparatus 120 during tube usage is passed to a system for monitoring and/or controlling the x-ray tube 100. A suitable computing device for implementing such a system is described below with respect to FIG. 3. The system 800 may be used to explain x-ray tube aging and failure. The sensor data enables the system 800 to perform spatial (and optionally spectral) monitoring of the emitted x-ray intensity profile cross-sectionally to the emission area (i.e. the focal spot). The anode disk surface roughens and takes micro-cracks during its lifetime, causing reduced x-ray intensities and modified emission spectra. Spatially resolved intensity monitoring can not only enable local anode disk damage to be identified, but also correlated to usage protocols in an operational history record. In one non-limiting example, the tube 100 is operated with a focal spot broadened to cover a maximum anode disk area such that, via spatial resolution of intensities, disk sections of damaged area are identifiable by comparing the measured intensities with those of disk sections which, in normal exposure modes, are less covered (or not at all) and which therefore provide juvenile intensities and spectra. The measured intensity profiles can thus be used for detection of changes or drift during the lifetime of the tube 100. The spatially resolved spectral measurements allow for analysis of the anode aging as the self-absorption depends on the crack geometry. Asymmetry may be detected by absorption changes of the spectral measurements left and right with respect to the center of the focal spot track.

[0042] FIGS. 2A and 2B show differences in the roughness of a used anode (FIG. 2A) as compared to a new anode (FIG. 2B). FIG. 2A shows a microphotograph 200A of the used anode while FIG. 2B shows that 200B of a new anode (taken on a middle track). The roughness of the used anode causes spectral changes via self-absorption in the surface structure, as illustrated by the spectra 202A of the used anode versus those 202B of the new anode. Such spectral detection allows effects in the cracks along the rotation direction or perpendicular to the rotation to be separated, providing additional information about the induced thermo-mechanical stress and the next expected surface modifications.

[0043] The system 800 may also correlate the monitored surface damage to usage of protocols in the operational history record of the x-ray tube 100, e.g. when using exposure modes involving different size, positions or thermal load of the x-ray source area. The severity of damage per protocol (or for combinations of protocols) can thereby be determined, enabling the recognition of especially malicious usage protocols or combinations thereof.

[0044] The system 800 may identify and implement measures for lifetime prolongation. For lifetime extension of the anode, the system 800 may adapt the operation mode of the x-ray system. In one non-limiting example, the system 800 adapts the cooling cycle (i.e. the break between scans) to avoid local overheating. In another non-limiting example, the system 800 enables additional melting and even re-melting (smart repair) of the anode surface using shifted focal spot positions (implemented for example via quadrupole/electron optics). The system 800 may use the known focal spot position to estimate the influence on the image (dual/quadruple focal spot). Focal spot position may be measured via the sensor apparatus 120. Optionally, additional sensor arrays and filters may be used to acquire more precise spectral information, particularly in the case that two or more focal spot positions are tracked in dual focal spot (DFS)/quadruple focal spot (QFS) mode. The system 800 may perform real-time intensity control to prolong tube life.

[0045] Using the real-time monitoring, the system 800 may detect and warn for acute damage to the anode disk 102, e.g. to set a call for maintenance service and avoid system failure during further operation. For instance, the system 800 may issue a warning if acutely progressing surface damage is detected. The system 800 may log data occasionally to provide a long-term reporting of the damage status. The system 800 may in addition monitor intensity peaks (high/low) to provide early detection of high voltage (HV) generator performance changes in combination with the electron beam performance. For example, close-to-arcing events could lead to lower intensities, which may be monitored by the system 800 using the sensor apparatus 120 without interfacing to the high voltage generator.

[0046] Systems and methods described herein find application in the fields of x-ray tube aging detection, predicative maintenance, and tube monitoring, being applicable in all kinds of x-ray imaging systems, especially those using rotating anode x-ray tubes.

[0047] Referring to FIG. 3, a high-level illustration of an exemplary computing device 800 that can be used in accordance with the systems and methods disclosed herein is illustrated. The computing device 800 may form part of or comprise any desktop, laptop, server, or cloud-based computing device. The computing device 800 includes at least one processor 802 that executes instructions that are stored in a memory 804. The instructions may be, for instance, instructions for implementing functionality described as being carried out by one or more components discussed above or instructions for implementing one or more of the methods described above. The processor 802 may access the memory 804 by way of a system bus 806. In addition to storing executable instructions, the memory 804 may also store conversational inputs, scores assigned to the conversational inputs, etc.

[0048] The computing device 800 additionally includes a data store 808 that is accessible by the processor 802 by way of the system bus 806. The data store 808 may include executable instructions, log data, etc. The computing device 800 also includes an input interface 810 that allows external devices to communicate with the computing device 800. For instance, the input interface 810 may be used to receive instructions from an external computer device, from a user, etc. The computing device 800 also includes an output interface 812 that interfaces the computing device 800 with one or more external devices. For example, the computing device 800 may display text, images, etc. by way of the output interface 812.

[0049] It is contemplated that the external devices that communicate with the computing device 800 via the input interface 810 and the output interface 812 can be included in an environment that provides substantially any type of user interface with which a user can interact. Examples of user interface types include graphical user interfaces, natural user interfaces, and so forth. For instance, a graphical user interface may accept input from a user employing input device(s) such as a keyboard, mouse, remote control, or the like and provide output on an output device such as a display. Further, a natural user interface may enable a user to interact with the computing device 800 in a manner free from constraints imposed by input device such as keyboards, mice, remote controls, and the like. Rather, a natural user interface can rely on speech recognition, touch and stylus recognition, gesture recognition both on screen and adjacent to the screen, air gestures, head and eye tracking, voice and speech, vision, touch, gestures, machine intelligence, and so forth.

[0050] Additionally, while illustrated as a single system, it is to be understood that the computing device 800 may be a distributed system. Thus, for instance, several devices may be in communication by way of a network connection and may collectively perform tasks described as being performed by the computing device 800.

[0051] Various functions described herein can be implemented in hardware, software, or any combination thereof. If implemented in software, the functions can be stored on or transmitted over as one or more instructions or code on a computer-readable medium. Computer-readable media include computer-readable storage media. Computer-readable storage media can be any available storage media that can be accessed by a computer. By way of example, and not limitation, such computer-readable storage media can comprise FLASH storage media, RAM, ROM, EEPROM, CD-ROM or other optical disk storage, magnetic disk storage or other magnetic storage devices, or any other medium that can be used to carry or store desired program code in the form of instructions or data structures and that can be accessed by a computer. Disk and disc, as used herein, include compact disc (CD), laser disc, optical disc, digital versatile disc (DVD), floppy disk, and Blu-ray disc (BD), where disks usually reproduce data magnetically and discs usually reproduce data optically with lasers. Further, a propagated signal is not included within the scope of computer-readable storage media. Computer-readable media also includes communication media including any medium that facilitates transfer of a computer program from one place to another. A connection, for instance, can be a communication medium. For example, if the software is transmitted from a website, server, or other remote source using a coaxial cable, fiber optic cable, twisted pair, digital subscriber line (DSL), or wireless technologies such as infrared, radio, and microwave, then the coaxial cable, fiber optic cable, twisted pair, DSL, or wireless technologies such as infrared, radio and microwave are included in the definition of communication medium. Combinations of the above should also be included within the scope of computer-readable media.

[0052] Alternatively, or in addition, the functionally described herein can be performed, at least in part, by one or more hardware logic components. For example, and without limitation, illustrative types of hardware logic components that can be used include Field-programmable Gate Arrays (FPGAs), Program-specific Integrated Circuits (ASICs), Program-specific Standard Products (ASSPs), System-on-a-chip systems (SOCs), Complex Programmable Logic Devices (CPLDs), etc.

[0053] It will be appreciated that the aforementioned circuitry may have other functions in addition to the mentioned functions, and that these functions may be performed by the same circuit.

[0054] The applicant hereby discloses in isolation each individual feature described herein and any combination of two or more such features, to the extent that such features or combinations are capable of being carried out based on the present specification as a whole in the light of the common general knowledge of a person skilled in the art, irrespective of whether such features or combinations of features solve any problems disclosed herein, and without limitation to the scope of the claims. The applicant indicates that aspects of the present invention may consist of any such individual feature or combination of features.

[0055] It has to be noted that embodiments of the invention are described with reference to different categories. In particular, some examples are described with reference to methods whereas others are described with reference to apparatus. However, a person skilled in the art will gather from the description that, unless otherwise notified, in addition to any combination of features belonging to one category, also any combination between features relating to different category is considered to be disclosed by this application. However, all features can be combined to provide synergetic effects that are more than the simple summation of the features.

[0056] While the invention has been illustrated and described in detail in the drawings and foregoing description, such illustration and description are to be considered exemplary and not restrictive. The invention is not limited to the disclosed embodiments. Other variations to the disclosed embodiments can be understood and effected by those skilled in the art, from a study of the drawings, the disclosure, and the appended claims.

[0057] The word comprising does not exclude other elements or steps.

[0058] The indefinite article a or an does not exclude a plurality. In addition, the articles a and an as used herein should generally be construed to mean one or more unless specified otherwise or clear from the context to be directed to a singular form.

[0059] A single processor or other unit may fulfil the functions of several items recited in the claims.

[0060] Measures recited in mutually different dependent claims may advantageously be combined.

[0061] 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 communications systems.

[0062] Any reference signs in the claims should not be construed as limiting the scope.

[0063] Unless specified otherwise, or clear from the context, the phrases one or more of A, B and C, at least one of A, B, and C, and A, B and/or C as used herein are intended to mean all possible permutations of one or more of the listed items. That is, the phrase X comprises A and/or B is satisfied by any of the following instances: X comprises A; X comprises B; or X comprises both A and B.