Smart power system and method to protect x-ray tube during power outage

Abstract

To provide a smart power system and method to protect an X-ray tube of a CT imaging system during a power outage.SOLUTION: The system and method comprise monitoring a remaining amount of power from a backup power source supplied by a UPS coupled to a PDU that is providing power to the CT imaging system. The X-ray tube has a liquid metal bearing rotating assembly. The system and method automatically strategize and determine where to supply the remaining amount of backup power in order to prevent a hot shutdown of the X-ray tube liquid metal bearing rotating assembly.SELECTED DRAWING: Figure 4

Description

[Technical Field]

[0001] SUMMARY OF THE INVENTION Embodiments of the subject matter disclosed herein relate to providing a smart power system and method for protecting an x-ray tube during a power outage. [Background technology]

[0002] A computed tomography (CT) imaging system may receive power from a mains power source, such as a utility power source. The utility power source may be connected to a utility power grid. During some conditions, the mains power source may be unavailable (i.e., unavailable for use by the CT imaging system) in response to a power outage, power grid instability, component failure, or other reason.

[0003] Some components inside a CT imaging system, such as the x-ray source or x-ray tube, may need to cool during shutdown before main power is removed from the CT imaging system. An unexpected power outage may damage some components, such as the x-ray source or x-ray tube, of a CT imaging system. It may be desirable to provide backup power during an unexpected main power disruption or outage to provide cooling routines for vulnerable components when main power becomes unavailable to protect and extend the life of these vulnerable components.

[0004] Hot landings of x-ray tubes with liquid metal bearings can occur during x-ray generator testing or during power outages. When an interruption or loss of power to the x-ray tube causes the rotating assembly of the liquid metal bearing to stop in an uncontrolled manner (i.e., the bearing stops rotating when it is hot), especially when the x-ray tube is hot, there is a possibility of bearing seizure, in which case the rotating members of the bearing melt along with the stationary members of the bearing, necessitating x-ray tube replacement and therefore CT imaging system downtime. X-ray tube replacement also involves one or more calibration routines, further extending system downtime.

[0005] Therefore, there is a need to provide a system and method for providing backup power to an x-ray tube during a primary power disruption or outage, which allows the x-ray tube to cool and the liquid metal bearing rotating assembly to gradually coast to a stop. Summary of the Invention

[0006] This summary introduces concepts that are more fully described in the detailed description. This summary is not intended to identify essential features of the claimed subject matter or to limit the scope of the claimed subject matter.

[0007] In one aspect, a method of providing backup power to a computed tomography (CT) imaging system includes monitoring the availability of power from a main power source to the CT imaging system, providing backup power to the CT imaging system via an uninterruptible power supply (UPS), distributing the backup power from the UPS to the CT imaging system via a power distribution unit (PDU), initiating a cool-down sequence for an x-ray tube of the CT imaging system, and monitoring the remaining backup power from the UPS during the cool-down sequence.

[0008] In another aspect, a computed tomography (CT) imaging system includes a gantry, an X-ray source coupled to the gantry, the X-ray source including an X-ray generator and an X-ray tube, a gantry controller coupled to the gantry, an X-ray controller coupled to the X-ray source, a power distribution unit (PDU) coupled to the gantry, a main power supply coupled to the PDU and providing power to the CT imaging system, a PDU controller coupled to the PDU, and an uninterruptible power supply (UPS) coupled to the PDU and providing backup power to the CT imaging system. The PDU is configured to distribute backup power from the UPS to the CT imaging system during a main power outage. The gantry controller is configured to initiate a cool-down sequence for the X-ray tube during a main power outage.

[0009] In yet another aspect, a smart power system and method for protecting an X-ray tube of a CT imaging system during a power outage includes monitoring remaining power from a backup power source provided by a UPS coupled to a PDU powering the CT imaging system. The X-ray tube has a liquid metal bearing rotating assembly. The system and method includes automatically scheduling and determining where to provide the remaining backup power to prevent a hot landing of the X-ray tube liquid metal bearing rotating assembly. [Brief explanation of the drawings]

[0010] The present disclosure will be more fully understood from the following detailed description of non-limiting embodiments, read in conjunction with the drawings, in which:

[0011] [Figure 1] 1 is a schematic diagram of a computed tomography (CT) imaging system coupled to a main power supply and other power components, according to an embodiment. [Figure 2] 1 is a block diagram of a CT imaging system according to an embodiment. [Figure 3] FIG. 1 is a block diagram of portions of a rotating gantry assembly (i.e., the rotating side of the gantry) and other components of a stationary gantry assembly (i.e., the stationary side of the gantry) of a gantry of a CT imaging system coupled with power components and an operator console according to an embodiment. [Figure 4] 1 is a schematic diagram of a power distribution unit (PDU) coupled to an uninterruptible power supply (UPS) according to an embodiment. [Figure 5] FIG. 2 is a schematic diagram of a first control circuit of a PDU according to an embodiment. [Figure 6] FIG. 10 is a schematic diagram of a second control circuit of a PDU according to an embodiment. [Figure 7]1 is a flow diagram of a system and method for controlling the switchover of a UPS backup power source to a CT imaging system in response to a mains power disruption or power outage, and for controlling the CT imaging system to return to mains power after mains power is restored, according to an embodiment. [Figure 8] FIG. 10 illustrates a timing sequence occurring after a main power outage according to an embodiment, the timing sequence including a method for controlling switchover of a backup power source to a CT imaging system in response to a main power outage to prevent hot shutdown of a liquid metal bearing of an X-ray tube of the CT imaging system. [Figure 9] 10A-10C illustrate warning messages that may be displayed on a user interface when a CT imaging system is running on backup power and is in the process of shutting down, according to an embodiment. DETAILED DESCRIPTION OF THE INVENTION

[0012] Embodiments of the present disclosure are described below, by way of example, with reference to the drawings, in which a smart power system and method, including a power distribution unit (PDU), an uninterruptible power supply (UPS), and operating software or firmware, provides backup power to several components of a computed tomography (CT) imaging system that may be damaged as a result of a main power disruption or outage. When a main power disruption or outage occurs, the smart power system and method detects the disruption or outage and switches power from the UPS to several components of the computed tomography (CT) imaging system, such as an X-ray source, to protect the X-ray tube during the outage. For example, an X-ray tube with a liquid metal bearing may be damaged during a hot shutdown of the liquid metal bearing. When a power disruption or loss to the X-ray tube causes the rotating assembly of the liquid metal bearing to hot shutdown in an uncontrolled manner (i.e., stop rotating when the bearing is hot), particularly when the X-ray tube is hot, there is a possibility of bearing seizure, in which case the rotating members of the bearing may melt along with the stationary members of the bearing, requiring the X-ray tube to be replaced. In an example embodiment, the present disclosure provides a system and method for deliberately cooling and shutting down a liquid metal bearing rotating assembly of an x-ray tube during a power outage.

[0013] Referring to the drawings, FIG. 1 illustrates an exemplary embodiment of a computed tomography (CT) imaging system 100 configured to image a subject, such as a patient, object, or other part. CT imaging system 100 includes a gantry 107 having a rotating gantry assembly and a stationary (i.e., non-rotating) gantry assembly. The rotating gantry assembly includes at least one X-ray source 104 configured to project a beam of X-ray radiation 106 (i.e., an X-ray beam) or X-rays toward a subject 204 being imaged (see FIG. 2). The rotating gantry assembly further includes at least one X-ray detector assembly 108 positioned directly opposite the X-ray source 104 on the rotating gantry assembly. The X-ray source 104 is configured to project the X-ray beam 106 toward the X-ray detector assembly 108 positioned on the opposite side of the gantry 107. At least one X-ray detector assembly 108 may include multiple X-ray detector elements or sensors (not shown) arranged in an array (i.e., an X-ray detector array). While FIG. 1 shows only a single X-ray source 104, other example embodiments may implement multiple X-ray sources and X-ray detectors that project multiple X-ray beams 106 toward the subject and X-ray detector to acquire projection image data at different energy levels. In some embodiments, at least one X-ray source 104 may enable dual-energy or multi-energy spectral imaging by rapidly switching the voltage potential (kVp) applied across the cathode and anode of the X-ray source. In some embodiments, the X-ray detector may be an energy integrating detector (EID) or a photon counting detector (PCD) capable of discriminating between X-ray photons of different energies. In other embodiments, dual-energy projections may be generated using two sets of X-ray sources and detectors, one set configured at a low kVp and the other set configured at a high kVp. Thus, it should be appreciated that the systems and methods described herein may be implemented with dual-energy or multi-energy acquisition approaches as well as single-energy acquisition approaches.

[0014] In some embodiments, the CT imaging system 100 further includes an image processor 110 configured to reconstruct images of a target volume of the imaged object using an iterative or analytical image reconstruction method. For example, the image processor 110 may reconstruct images of the target volume of the patient using an analytical image reconstruction approach, such as filtered back projection (FBP). As another example, the image processor 110 may reconstruct images of the target volume of the object 112 using an iterative image reconstruction approach, such as advanced statistical iterative reconstruction (ASIR), conjugate gradient (CG), maximum likelihood expectation maximization (MLEM), model-based iterative reconstruction (MBIR), and other iterative image reconstruction methods. As described in more detail herein, in some other embodiments, the image processor 110 may use both an analytical image reconstruction approach, such as FBP, in addition to an iterative image reconstruction approach.

[0015] In some CT imaging system configurations, an x-ray source projects a cone-shaped x-ray beam (i.e., cone beam scanning), which is collimated to lie within the XYZ plane of a Cartesian coordinate system, commonly referred to as the "imaging plane." The x-ray beam passes through an object being imaged, such as a patient. After being attenuated by the object, the x-ray beam strikes an array of detector elements. The intensity of the attenuated x-ray beam received by the detector array depends on the attenuation of the x-ray beam by the object. Each x-ray detector element in the x-ray detector array generates a separate electrical signal, which is a measurement of the x-ray beam attenuation at the x-ray detector location. The attenuation measurements from all x-ray detector elements are acquired separately to generate a profile of image data.

[0016] As mentioned above, in some CT imaging systems, the x-ray source and x-ray detector are rotated within the imaging plane and around the object by a rotating gantry assembly so that the angle at which the x-ray beam intersects the object is constantly changing. A group of x-ray attenuation measurements, e.g., projection data, from the x-ray detector array at one gantry angle is called a "view." A "scan" of the object comprises a set of views made at different gantry angles, or view angles, during one rotation of the x-ray source and detector.

[0017] The projection data is processed to reconstruct an image corresponding to a two-dimensional slice through the imaged object, or in some instances where the projection data includes multiple views or scans, to reconstruct a three-dimensional representation of the imaged object. As previously mentioned, one method for reconstructing an image from a set of projection data is referred to in the art as a filtered backprojection technique. Transmission and emission tomography reconstruction techniques also include statistical iterative methods such as maximum likelihood expectation maximization (MLEM) and ordered subset expectation reconstruction, in addition to other iterative reconstruction techniques. This process converts the attenuation measurements from the scan into integers called "CT numbers" or "Hounsfield units," and these values ​​are used to control the brightness of corresponding pixels on a display device.

[0018] To reduce total scan time, a "helical" scan can be performed. To perform a "helical" scan, the patient is moved during the image acquisition scan while data for a predetermined number of slices is acquired. Such systems generate a helix from a cone-beam helical scan. This helical cone-beam image acquisition scan produces projection data from which images in each predetermined slice can be reconstructed.

[0019] The phrase "reconstructing an image," as used herein, is not intended to exclude embodiments of the present disclosure in which data representing an image is generated but no visible image is formed. Thus, as used herein, the term "image" broadly refers to both a visible image and data representing a visible image. However, many embodiments form (or are configured to form) at least one visible image.

[0020] 1 further illustrates that the CT imaging system 100 receives power from a main power source 122, such as utility power provided by an electrical grid, or from an uninterruptible power supply (UPS) 124 through a power distribution unit (PDU) 120. The PDU is controlled by and electrically coupled to a PDU controller 130. The main power source 122 is electrically coupled to the PDU 120 and provides three-phase AC power to the PDU 120. The UPS 124 is electrically coupled to the PDU 120. The PDU 120 is electrically coupled to the CT imaging system 100 and provides AC and high-voltage DC (HVDC) power to the CT imaging system 100. The UPS 124 is configured to act as a backup power source for the CT imaging system 100 during a disruption or power outage of the main power source 122.

[0021] In one example embodiment, the PDU 120 may include one or more sensors configured to sense the availability of power from the main power source 122. The PDU controller 130 may be configured to receive feedback from the one or more sensors and control one or more actuators in response to the availability of power from the main power source 122 as well as command signals from a gantry control board located in the gantry 107. The one or more actuators may operate after a specific time delay or delay period measured by a timer. In one example embodiment, the one or more actuators are contactors and / or switches configured to divert power to the CT imaging system from the main power source 122 to the UPS 124 based on the availability of power from the main power source 122. In one example embodiment, if there is an outage or disruption of power from the main power source 122, the PDU controller 130 may send at least one signal to activate at least one contactor or switch to open a circuit coupling the main power source 122 to the CT imaging system and to activate at least one contactor or switch to close a circuit coupling the UPS 124 to the CT imaging system. This will be explained in more detail later.

[0022] The PDU controller 130 may include at least one printed circuit board (PCB) with multiple electronic components, at least one of which may have executable instructions stored in a memory that, when executed, causes the PDU controller 130 to send signals that control contactors to divert power to the CT imaging system between the main power source 122 and the UPS 124 based on the availability of power from the main power source 122. Power from the main power source 122 may be detected via a current sensor, a voltage sensor, or other type of power sensor. Triggered by feedback from the power sensor, the PDU controller 130 may send signals to operate contactors or switches that couple or couple the UPS 124 while coupling or uncoupling the main power source 122 after a time delay, thereby switching the connection from the main power source 122 to the UPS 124 and outputting the PDU 120 load to power the CT imaging system 100.

[0023] FIG. 2 illustrates an exemplary embodiment of a block diagram of an imaging system 200 similar to the CT system 100 of FIG. 1. In accordance with an aspect of the present disclosure, the imaging system 200 is configured to image an object 204. In an exemplary embodiment, the CT imaging system 200 includes an x-ray source 104 and an x-ray detector array 108 within a gantry 107 of the CT imaging system 200. The detector array 108 includes a plurality of detector elements 202 that collectively measure x-rays from the attenuated x-ray beam 106 after passing through the object 204 being imaged, such as a patient, to obtain corresponding projection image data. Thus, in an exemplary embodiment, the detector array 108 is fabricated in a multi-slice configuration including multiple rows of cells or detector elements 202. In such a configuration, one or more additional rows of detector elements 202 may be arranged in a parallel configuration to obtain projection image data.

[0024] In some embodiments, the CT imaging system 200 is configured to traverse various angular positions about the object 204 to acquire the desired projection image data. Accordingly, the gantry 102 and components mounted to the gantry 102 may be in the form of a rotating gantry assembly configured to rotate about a center of rotation 206 to acquire the projection image data. As the x-ray source 104 and detector array 108 rotate about the object 204, the detector array 108 measures and collects data of the attenuated x-rays. The data collected by the detector array 108 is preprocessed. The preprocessed data is generally referred to as projection data. In some embodiments, the x-ray detector array 108 may be configured as either an energy integrating detector (EID) or a photon counting detector (PCD).

[0025] In one example embodiment, the acquired projection data may be subjected to basis material decomposition (BMD). During the BMD process, the measured projection data is converted into material density projection data. The material density projection data may be reconstructed to form a set of material density maps or images for each respective basis material, such as a bone map, a soft tissue map, and / or a contrast agent map. These material density maps or images may be used to form a volume rendering of the basis materials, e.g., bone, soft tissue, and / or contrast agent, in the imaged volume.

[0026] Image reconstruction of the basis material images produced by the imaging system 200 reveals internal features of the subject 204, represented as the density of each basis material. Density images may be displayed to show these internal features. In a traditional approach to diagnosing a medical condition, such as a disease state, a radiologist, attending physician, or other physician may review the density images to identify certain features of interest. Such features may include lesions, tumors, the size and shape of particular anatomical structures or organs, and other features deemed identifiable in the image based on the skill and expertise of the individual radiologist, attending physician, or other physician.

[0027] 2, the CT imaging system 200 may include a controller subsystem 208 that controls the operation of various components of the CT imaging system 200. The controller subsystem 208 includes a table controller 208 that controls the movement of the table 114, an x-ray controller 210 that controls the operation of the x-ray source 104, and a gantry controller 212 that controls the movement and rotation of the rotating gantry assembly of the gantry 107.

[0028] CT imaging system 200 further includes a data acquisition system (DAS) 214 configured to receive analog data from detector elements 202 and convert the analog data to digital data for subsequent processing. The digitized data received by DAS 214 is transmitted to a computing device 216 and / or an image reconstructor for processing. In one example, computing device 216 may be one or more computers that store the digital data in memory or storage device 218 coupled to computing device 216.

[0029] Additionally, the computing device 216 may be coupled to one or more of the table controller 226, the x-ray controller 210, the gantry controller 212, the DAS 214, and / or the image reconstructor 230 to provide instructions and / or parameters to these elements to control system operations such as image acquisition, data measurement and collection, and / or processing. In some embodiments, the computing device 216 controls system operations of the CT imaging system. The computing device 216 may receive operator input from a technician or operator of the CT imaging system via an operator console 220 operatively coupled to the computing device 216, including, for example, instructions, scanning parameters, imaging protocols, or operating protocols, requesting an examination, plotting data, and / or viewing data and / or images. The operator console 220 may include at least one user display 232, a keyboard, a touch screen, or other input device that enables the technician or operator to control the operation of the CT imaging system 200.

[0030] 2 shows only one operator console 220, more than one operator console or workstation may be coupled to imaging system 200, for example, to enter commands, scan parameters, imaging protocols, or operating protocols, request exams, plot data, and / or view data and / or images. Additionally, in some embodiments, imaging system 200 may be coupled to multiple displays, printers, workstations, and / or similar devices, which may be located locally or remotely, for example, within a medical facility or hospital, or in entirely different locations, and may be coupled via one or more configurable wired and / or wireless networks, such as the Internet and / or virtual private networks, wireless telephone networks, wireless local area networks, wired local area networks, wireless wide area networks, and wired wide area networks, etc.

[0031] In one example embodiment, imaging system 200 may include or be coupled to a picture archiving and communication system (PACS) 224. In another example embodiment, PACS 224 may be further coupled to a remote system, such as a radiology information system or a hospital information system, and / or a local or external network (not shown), allowing personnel at various locations to provide commands and parameters and access image data.

[0032] The computing device 216 uses operator-supplied and / or system-defined commands and parameters to operate the table controller 226, which in turn can control the movement of the table 114, which can be a motorized table. Specifically, the table controller 226 can move the table 114 to appropriately position a subject 204, which is placed on the table, within an opening or bore of the gantry 107 to acquire projection data corresponding to a target volume of the subject 204, such as a patient being imaged.

[0033] As previously mentioned, DAS 214 samples and digitizes the projection data acquired by detector elements 202. An image reconstructor 230, coupled to DAS 214 and computing device 216, then performs high-speed reconstruction using the measured and digitized x-ray data. While FIG. 2 depicts image reconstructor 230 as a separate component, in some embodiments, image reconstructor 230 may be included within computing device 216, one or more processors, edge computers, or one or more servers, including cloud computing capabilities. As noted above, image reconstructor 230 need not be a separate component of CT imaging system 200; instead, computing device 216 may perform one or more functions of image reconstructor 230. Also, image reconstructor 230 may be located locally or remotely and operatively connected to imaging system 200 using a wired or wireless network. In another example embodiment, computing resources available in a “cloud” network may be used to perform one or more functions of image reconstructor 230.

[0034] In an example embodiment, image reconstructor 230 may store the reconstructed image in storage device 218. Alternatively, image reconstructor 230 may transmit the reconstructed image to computing device 216 for generating patient information useful for evaluation and diagnosis. In some embodiments, computing device 216 may transmit the reconstructed image and / or patient information to user display 232 for viewing. In some embodiments, the reconstructed image may be transmitted from computing device 216 or image reconstructor 230 to storage device 218 for short-term or long-term storage.

[0035] 1 can be used as a backup power source to power computing device 216 and its auxiliary components (e.g., operator console 220 and / or user display 232, etc.) during a main power disruption or power outage. As explained in more detail below, PDU 120 and UPS 124 of FIG. 1 are configured to provide backup power not only to computing device 216 and its auxiliary components during a main power disruption or power outage, but also to components internal to the rotating gantry assembly, such as the x-ray source, x-ray generator, and x-ray controller. During normal operation, when main power is available, the main power is used to charge the UPS's backup power source, such as the UPS's multiple batteries and / or capacitors.

[0036] FIG. 3 is a block diagram of a portion of the rotating gantry assembly 318 (i.e., the rotating side of the gantry) of the gantry 107 of a CT imaging system, to which the power components and operator console are coupled, and other components of the stationary gantry assembly (i.e., the stationary side of the gantry). Similar to that shown in FIG. 1, a main power source 122, such as a utility power source, is electrically coupled to a PDU 120, which is electrically coupled to a UPS 124 and a PDU controller 130. The UPS 124 is used to provide backup power during a disruption or power outage of the main power source 122. The UPS 124 may include multiple batteries or multiple storage capacitors for storing backup power, which can be used in the event of a main power disruption or power outage. The UPS 124 includes a UPS Ethernet board 302 that can communicate with a PDU control board 304 within the PDU 120 and the operator console 220. The PDU control board 304 may be in communication with a gantry control board 316 within the gantry controller 212 and may be configured to detect the availability of power from the main power source 122 .

[0037] In one example embodiment, the PDU control board 304 can include a sensor circuit including one or more sensors that constantly monitor the availability of the main power source 122, detecting power disruptions or outages in real time. In one example embodiment, the PDU control board 304 can be configured to receive signals from the one or more sensors and control one or more actuators in response to the availability of power from the main power source 122, as well as to send signals to one or more of the operator console 220 and / or gantry control boards 316 indicating the availability of power from the main power source 122. These signals can be sent through and / or processed by the computing device 216.

[0038] In an example embodiment, if the PDU control board 304 detects a power disruption or power outage from the main power source 122, the PDU control board 304 automatically switches the CT imager from receiving power from the main power source 122 to receiving power from the UPS 124 or backup power source to ensure a safe shutdown of the x-ray tube liquid metal bearing rotating assembly. If the PDU control board 304 detects the restoration of power from the main power source 122, the PDU control board 304 automatically switches the CT imager back to receiving power from the main power source and resumes normal operation without input from a technician or operator.

[0039] In an exemplary embodiment, the main power supply 122 is electrically coupled to the PDU 120. The PDU 120 is electrically coupled to the PDU controller 130, the UPS 124, and the gantry controller 212. If power from the main power supply 122 is disrupted or lost, a smart power system or method automatically switches the CT imaging system power from the main power supply 122 to the UPS 124, or backup power source, to provide backup power to the CT imaging system, including the operator console 220 and the gantry 107. The portion of the gantry 107 shown in FIG. 3 includes a gantry controller 212 with a gantry control board 316 coupled to a rotating gantry assembly 318 (i.e., the rotating side of the gantry). The gantry control board 316 is coupled to the X-ray controller 210. The gantry control board 316 is also coupled to the operator console 220. The portion of the gantry 107 shown in FIG. 3 also includes a power inverter 308, which is coupled to the rotating gantry assembly 318. The rotating gantry assembly 318 includes an X-ray controller 210 coupled to an X-ray generator and X-ray tube 310. An X-ray generator 312 is coupled to the X-ray tube 310 and provides power to the X-ray tube 310. The X-ray controller is further coupled to an operator console 220. A power inverter 308 is specifically coupled to the X-ray generator 312. The power inverter 308 receives DC power from the PDU 120 and converts the DC power to AC power for input to the X-ray generator 312.

[0040] During a power outage or loss of the main power supply 122, the UPS 124 provides backup power that allows the CT imaging system 100 to complete a cool-down sequence to cool the X-ray tube liquid metal bearing before powering down the CT imaging system or restoring the CT imaging system to normal operation. Backup power from the UPS 124 or from the main power supply is provided to the X-ray generator 312 by a power inverter 308. The X-ray controller 210 can receive commands from the operator console 220 to power on or off the rotating gantry assembly 318. For example, during a cool-down operation of the X-ray tube 310, the X-ray controller 210 can receive at least one command from the operator console 220 to remove power from the X-ray generator 312 and the X-ray tube 310, thereby initiating the X-ray tube cool-down operation and coasting the X-ray tube's liquid metal bearing rotating assembly to a natural stop. In some examples, the liquid metal bearing rotating assembly can coast down for a specified period of time during the cool-down sequence. Additionally or alternatively, if the UPS is running low on power (e.g., less than 7 minutes of backup power remaining), the rotating assembly liquid metal bearings may be forced to begin coasting to a stop. Additionally, the X-ray controller may receive at least one command or signal to return to normal operation and restore power to the X-ray generator and X-ray tube once main power is restored.

[0041] The X-ray tube 310 requires cooling after use to prevent damage to the X-ray tube components, particularly the X-ray tube's liquid metal bearing. In the event of a power outage (e.g., when power from the main power supply 122 is unavailable), an X-ray tube cool-down sequence is initiated to allow the X-ray tube to cool safely before completely shutting down the CT imaging system. In some examples, when the X-ray tube cool-down sequence is initiated, the X-ray controller can receive one or more signals (e.g., from the operator console 220) to initiate coasting deceleration of the liquid metal bearing rotating assembly to a stop. In one such example, the signal to initiate the cool-down sequence can be sent after a hardware reset. Additionally or alternatively, the signal to initiate coasting of the liquid metal bearing rotating assembly can be sent when the PDU 120 determines that the UPS 124 has limited backup power remaining. In other words, the UPS Ethernet board 302 communicates with the UPS 124 to inform the operator or technician of the amount of backup power remaining in the UPS 124 and automatically determines how best to utilize the remaining backup power to protect the X-ray tube from damage.

[0042] Although a CT imaging system is described as an example, it should be understood that the present systems and methods may also be useful when applied to other multi-modality imaging systems that include an x-ray source or x-ray tube, such as a positron emission tomography and computed tomography (PET / CT) imaging system or a single photon emission computed tomography and computed tomography (SPECT / CT) imaging system.

[0043] FIG. 4 is a schematic diagram of a PDU 120 coupled to a UPS 124 according to an embodiment. An embodiment of the power interface between the UPS 124 and the main power source 122 and the PDU 120 is shown. As such, the aforementioned components may be similarly numbered in these figures. The PDU 120 may receive three-phase AC input power from the main power source 122, a circuit breaker 402, three-phase AC power wiring 408, and a three-phase input 404 to a transformer 405. The transformer 405 may have a primary winding or three-phase input 404, a first secondary winding 410, and a second secondary winding 430. The circuit breaker 402 may be configured to trip in response to a current greater than 150 amperes flowing through the three-phase AC power wiring 408.

[0044] The first secondary winding 410 can include a higher voltage than the second secondary winding 430 and can direct power via electrical wiring 412 through fuses and other electrical components to a rectifier 416. In some examples, the electrical wiring 412 can be coupled to fuses configured to interrupt a circuit in response to current flowing through the electrical wiring 412 exceeding the fuse rating. A plurality of contactors KXG 415 and KSS 414 can be disposed between the first secondary winding 410 and the rectifier 416. The rectifier 416 can be a passive or active rectifier and configured to convert alternating current (AC) to direct current (DC) at the output of the rectifier 416. The output of the rectifier 416 is coupled to an output high-voltage DC (HVDC) load 420, which can be coupled to components coupled to the rotating gantry assembly to provide power to these components. In one example, the HVDC can be greater than 600 VDC.

[0045] The second secondary winding 430 can direct three-phase AC power to an input 446 of the UPS 124 via electrical wiring 432 and a circuit breaker. An output 447 of the UPS 124 supplies three-phase AC power to the PDU 120 and its output AC load 440, which powers other components of the CT imaging system, such as an operator console, a power cabinet, and computing equipment. The three-phase AC output of the UPS can also be supplied to the PDU 120 through a circuit breaker and contactor KBK 450A to the autotransformer 406. The output of the autotransformer 406 is coupled to a rectifier 417, which converts the three-phase AC input to an HVDC output. The HVDC output of the rectifier 417 can be coupled to a fuse and contactor KDC 455 to the output HVDC load 420.

[0046] 5 and 6 illustrate a first control circuit (FIG. 5) and a second control circuit (FIG. 6) of a PDU according to an embodiment. The first and second control circuits receive power from the UPS AC output phase B and 24 VDC from the PDU. UPS 124 input phase B provides 120 V to the first control circuit. Only a single AC phase (e.g., phase B) is used to power the first control circuit because only one phase is needed to determine if a power outage has occurred and trigger the first control circuit to begin a response to the power outage. Specifically, contactor KJC442 operates to detect a loss of mains power from the UPS via phase B, so the KJC contactor triggers the response to the power outage. In alternative embodiments, power may come from phase A or phase C instead. The second control circuit is coupled to the gantry control board via connector J3, signals XG_Cont and Sys_XG_Cont.

[0047] The first and second control circuits include a plurality of three-phase contactors KJC 442, 442A, and 442B, KBK 450, 450A, KDC 455, 450A, a plurality of timers DR 457, 457A, TR 456, 456A, and a plurality of relays R1 444, 444A, 444B, 444C, and R2 454, 454A. In an illustrative example, DR 457 closes after a 10-second delay from the time mains power from mains power source 122 becomes unavailable, KBK 450A closes following an XG_Cont signal, and TR 456 and KDC 455 close one second after KBK 450A closes. The gantry control board sends a signal XG_Cont to the PDU. An exemplary XG_Cont signal may be provided after a fixed delay (e.g., 12.5 seconds after power failure). This signal initiates the X-ray tube cool-down sequence. The delay preceding the XG_Cont signal ensures that power from the main power supply 122 has been unavailable for a significant enough period of time to initiate the X-ray tube cool-down sequence, rather than a temporary power outage or power surge.

[0048] FIG. 7 is a flow diagram of a system and method for controlling the switchover of UPS backup power to a CT imaging system in response to a mains power disruption or outage and for controlling the CT imaging system's return to mains power after mains power is restored, according to an embodiment. For example, if mains power becomes unavailable, the system automatically switches to backup power from the UPS. The UPS operates to provide backup power during an X-ray tube cool-down sequence, which is part of a CT imaging system's safe shutdown and prevents damage to the X-ray tube. Executable instructions for the method may be stored in a memory of the electronics component and executed by a computing device and / or a PDU controller. The PDU controller may be configured to receive input from one or more sensors in a sensor circuit of the PDU that constantly monitors the availability of power from the mains power source, detect a power disruption or outage in real time, and automatically switch to backup power from the UPS when a power disruption or mains power outage is detected.

[0049] Method 700 begins at step 702, which includes a CT imaging system operating under normal conditions. Normal conditions may include receiving power from a mains power source, such as a utility power source. While operating under normal conditions, all functions of the CT imaging system are available. During operation of the CT imaging system, a loss of power from the mains power source may occur at step 704. Under a mains power outage, there is no HVDC power from the PDU to the gantry at step 706. At step 708, the gantry control board detects the loss of power. Because the gantry is no longer powered, many of the functions of the CT imaging system are inoperable. After a certain amount of delay (e.g., 12.5 seconds), the gantry control board can send a signal to the PDU control board of the PDU controller and / or operator console to switch to backup power from the UPS to provide HVDC to the gantry at step 710. This delay ensures that the outage is not simply a limited power disruption or power surge that does not require initiation of a cooling sequence.

[0050] If the backup HVDC power is successfully turned on, the gantry control board sends a command to start powering the X-ray generator, including the X-ray controller and X-ray tube, in step 710. The X-ray tube protection mechanism is triggered to start controlling the X-ray tube's liquid metal bearing rotating assembly and to initiate the X-ray tube cool-down sequence in step 712. The gantry control board and / or PDU control board begin monitoring remaining backup power information from the UPS. In step 714, the gantry control board and / or PDU control board determine whether the UPS has enough backup power remaining to initiate the X-ray tube cool-down sequence. If the gantry control board and / or PDU control board determine in step 716 that the UPS has enough backup power remaining, the cool-down sequence continues in step 718. During the cool-down sequence, the gantry control board and / or PDU control board continue to monitor the status of the main power supply to determine whether utility power has been restored in step 720. If main power is restored before the X-Ray tube liquid metal bearing rotating assembly cool-down sequence is completed in step 722, the gantry control board and / or PDU control board will abort the X-Ray tube liquid metal bearing rotating assembly cool-down sequence and the rotating assembly will return to normal operating conditions in step 702. The system will be able to return to normal operating conditions without any additional action or intervention from the operator or technician.

[0051] If the main power supply 122 is not restored during the rotating assembly cool-down sequence in step 718, the gantry control board and / or PDU control board checks whether the required rotating assembly cool-down sequence is complete in step 724. If the rotating assembly cool-down sequence is not complete in step 724, the gantry control board and / or PDU control board continues to monitor the remaining backup power in the UPS in step 716 and the status of the main power supply in step 720 until either the main power supply is restored, thereby restoring the CT imaging system to normal operation, or the cool-down sequence is complete. The system can return to normal operation without any additional action or intervention from the operator or technician.

[0052] If the cool-down sequence is complete in step 724 or if there is insufficient backup power remaining in the UPS to complete the cool-down sequence in step 716, the gantry control board and / or PDU control board initiate a controlled shutdown of the rotating assembly in step 726. After several minutes have elapsed, the rotating assembly is shut down in step 728. The gantry control board and / or PDU control board continue to monitor the status of the main power supply and check whether utility power has been restored in step 730. If main power is restored, the system returns to normal operation in step 702. If main power is not restored, the system remains in a waiting state until the UPS backup power is nearing full depletion (e.g., less than three minutes remaining) in step 732. When the UPS backup power is nearing full depletion, the system automatically initiates a shutdown in step 734 to prevent unforeseen damage to the CT imaging system due to a sudden power loss. In this manner, the CT imaging system is shut down in a controlled manner and completely shut down in step 736. Method 700 is complete.

[0053] FIG. 8 is another diagram of a method 800 including a timing sequence that occurs after a mains power outage to control switching to a UPS backup power supply to a CT imaging system in response to a mains power outage to prevent hot stall of the liquid metal bearing rotating assembly of the X-ray tube in the CT imaging system. Hot stall of the liquid metal bearing rotating assembly of the X-ray tube can occur during a power outage. When the loss of power to the X-ray tube causes the liquid metal bearing rotating assembly to stall (i.e., stop rotating) in an uncontrolled manner, bearing seizure can occur, particularly if the X-ray tube is hot, requiring replacement of the X-ray tube. Therefore, when a power outage occurs, it is desirable to switch to backup power to the X-ray tube to allow the X-ray tube to cool and the liquid metal bearing rotating assembly to coast to a stop.

[0054] In one example embodiment, a method for switching power to a CT imaging system from mains power to backup power from a UPS after a mains power loss begins at zero (0) seconds with the gantry control board and / or PDU control board detecting a mains power outage (i.e., a mains power loss during which the PDU does not provide power to the gantry and X-ray tube). After a short period of time (e.g., 13 seconds), the UPS begins providing power to the gantry and X-ray tube. The gantry control board sends a signal to initiate a switch from mains power to the gantry to backup power from the UPS. After a few more seconds (e.g., 15 seconds after mains power loss), HVDC power is provided to the gantry and X-ray tube from the UPS. The gantry control board detects that power is being provided by the UPS. A warning message may be displayed on a user display indicating the mains power loss, and imaging reconstruction may be frozen.

[0055] Approximately 70 seconds after the loss of main power, the status of the X-ray tube's liquid metal bearing rotating assembly can be displayed on the display user interface, and the rotating assembly continues to rotate. A short time after this (e.g., approximately 75 seconds after the loss of main power), the rotating assembly shutdown process (cool-down sequence) begins. During this time, the liquid metal bearing rotating assembly speed is approximately 50 Hz, and the heat exchanger pump is running at 5 volts. Approximately 122 seconds after the loss of main power, the scanning hardware reset is complete. Approximately 217 seconds after the loss of main power, the rotating assembly shutdown process (cool-down sequence) reaches a point where the rotating assembly begins to coast. In some example embodiments, coasting of the rotating assembly begins when the UPS has approximately 7 minutes or less of backup power remaining. Approximately 543 seconds after the loss of main power, the X-ray tube's liquid metal bearing rotating assembly stops and ceases rotation. As the coasting gradually subsides, the rotating assembly coasts to a stop. The user interface display may display a message indicating that the rotating assembly has stopped rotating. If main power is restored at this point, the CT imaging system will return to normal operation approximately 40 minutes after the loss of main power. The CT imaging system will automatically return to normal operation without any action or intervention from the operator or technician. The user interface display may display a message indicating that the CT imaging system is under normal operation, and image reconstruction will unfreeze. If main power is not restored after the rotating assembly has stopped rotating, the UPS may have approximately 20 minutes of backup power remaining. At this point, the remaining backup power will be depleted, and the operator console will shut down and the UPS will shut down.

[0056] 9 is an example of a warning message 900 that may be displayed on the user interface display 232 when the CT imaging system is relying on backup power and is in the process of shutting down. This example warning message 900 provides information that the CT imaging system is relying on backup power and is in the process of safely shutting down. The warning message 900 may also include an estimated amount of time the shutdown process will take and instructions for the operator or technician. Additionally or alternatively, the user interface display 232 may display other warning messages, such as an indication that the UPS backup power will soon be depleted and the system may shut down, an indication of the amount of UPS backup power remaining, an indication that main power has been restored and normal operation may resume, etc.

[0057] As used herein, the use of a singular element or step preceded by the indefinite article "a," "an," or "the" should be understood as not excluding a plurality of such elements or steps, unless the exclusion is expressly stated. Furthermore, references to "one embodiment" of an invention do not exclude the existence of additional embodiments that also incorporate the recited features. Further, unless expressly stated to the contrary, embodiments that "comprise," "include," or "have" an element or elements having a particular characteristic may also include additional elements that do not possess that characteristic. Furthermore, the term "including" is used as a standard language equivalent of "comprising," and the term "in which" is used as a standard language equivalent of "wherein." Furthermore, terms such as "first," "second," and "third" are used merely as labels and do not impose numerical requirements or a particular positional order on the objects of these terms.

[0058] The methods and processes disclosed herein can be stored as executable instructions in non-transitory memory and executed by a control system including at least one processor or at least one controller in combination with various sensors, actuators, contactors, switches, and other electrical or electronic hardware. Particular methods and / or processes described herein may represent one or more of any number of processing strategies, such as event-driven operation, interrupt-driven operation, multitasking operation, multithreaded operation, etc. As such, the various illustrated acts, operations, and / or actions may be performed in the order shown, in parallel, or in some cases omitted. Similarly, the order of processes or steps is not necessarily required to achieve the features and advantages of the example embodiments described herein, but is presented for ease of illustration and description. One or more of the illustrated acts, operations, and / or steps may be performed repeatedly depending on the particular strategy being used. Additionally, the described operations, acts, acts, and / or steps may be graphically represented as code to be programmed into a non-transitory memory of a computer-readable storage medium of a system and / or one or more processors, where the described operations are performed by executing instructions of the system or system including various electrical and electronic components in combination with one or more controllers.

[0059] The embodiments of the present disclosure illustrated in the drawings and described above are merely exemplary embodiments and do not limit the scope of the claims, including any equivalents within their scope. Various modifications are possible and will be readily apparent to those skilled in the art. Any combination of non-mutually exclusive features described herein is intended to be within the scope of the present invention. That is, features of the described embodiments may be combined with any appropriate aspect described above, and optional features of any one aspect may be combined with any appropriate aspect of any other. Similarly, features described in a dependent claim may be combined with non-mutually exclusive features of other dependent claims, particularly when each dependent claim is dependent on the same independent claim. Single-item dependency may be used as required for implementation in some jurisdictions, but should not be construed to mean that the features of the dependent claims are mutually exclusive. [Explanation of symbols]

[0060] 100 CT Imaging System 104 X-ray source 106 X-ray beam 107 Gantry 108 detector array 114 Tables 200 Imaging System 202 detector element 204 Subject 206 Center of rotation 208 Control Mechanism 318 Rotating Gantry Assembly 402 Circuit Breaker (CB1) 404 Three-phase input 405 Transformer 406 Autotransformer 408 Three Phase AC Power Wiring 410 First secondary winding 412, 432 Electrical wiring 430 Secondary Winding 442, 442A, 442B three phase contactor KJC 444, 444A, 444B, 444C Relay R1 446 Terminal Block (Input to UPS) 447 Terminal block (output from UPS) 450, 450A three-phase contactor KBK 451 452 454, 454A relay R2 455, 455A three phase contactor KDC 456, 456A Timer TR 457, 457A Timer DR 700 System and method for controlling power supply switching during power outage and restoration after power restoration 800 Method including timing sequence for controlling switchover to backup power source 900 Warning Message

Claims

1. 1. A method for providing backup power to a computed tomography (CT) imaging system, comprising: monitoring the availability of power from a mains power source to the CT imaging system; providing backup power to the CT imaging system via an uninterruptible power supply (UPS); distributing the backup power from the UPS to the CT imaging system via a power distribution unit (PDU); initiating a cool-down sequence for an x-ray tube of the CT imaging system; monitoring the remaining backup power from the UPS during the cooling sequence; A method comprising:

2. 2. The method of claim 1, further comprising detecting a power outage of the main power source and automatically switching power to the CT imaging system from the main power source to the backup UPS power source.

3. 2. The method of claim 1, further comprising the steps of detecting restoration of power from the main power source and automatically switching power to the CT imaging system from the backup UPS power source to the main power source.

4. 10. The method of claim 1, further comprising the step of, upon supplying backup power to the CT imaging system, displaying an indication of CT imaging system status and power availability on a display on an operator console coupled to the CT imaging system.

5. 4. The method of claim 3, further comprising the step of restoring the CT imaging system to normal operation after automatically switching power to the CT imaging system from the backup UPS power source to the main power source.

6. 10. The method of claim 1, further comprising determining whether the amount of backup power remaining in the UPS is sufficient to complete the cooling sequence.

7. 7. The method of claim 6, further comprising the step of forcing the x-ray tube rotating assembly to coast if the amount of backup power remaining in the UPS is not sufficient to complete the cool-down sequence.

8. 2. The method of claim 1, wherein the cooling sequence includes sending at least one signal to an x-ray controller to initiate the cooling sequence to prevent hot shutdown of the x-ray tube.

9. 10. The method of claim 1, further comprising the step of waiting a period of time before initiating the cooling sequence.

10. The gantry and an x-ray source coupled to the gantry, the x-ray source including an x-ray generator and an x-ray tube; a gantry controller coupled to the gantry; an x-ray controller coupled to the x-ray source; a power distribution unit (PDU) coupled to the gantry; a main power supply coupled to the PDU for powering the computed tomography (CT) imaging system; a PDU controller coupled to the PDU; an uninterruptible power supply (UPS) coupled to the PDU for providing backup power to the CT imaging system; 1. A computed tomography (CT) imaging system comprising: the PDU is configured to distribute the backup power from the UPS to the CT imaging system during a power outage of the main power source; The computed tomography (CT) imaging system, wherein the gantry controller is configured to initiate a cool-down sequence for the x-ray tube during the power outage of the main power supply.

11. The CT imaging system of claim 10 , wherein the PDU controller is configured to monitor the main power source for power outages.

12. 12. The CT imaging system of claim 11, wherein the PDU controller, upon detecting a loss of the main power source, automatically switches power to the CT imaging system from the main power source to the backup UPS power source.

13. 12. The CT imaging system of claim 11, wherein the PDU controller, upon detecting the restoration of power from the main power source, automatically switches power to the CT imaging system from the backup UPS power source to the main power source.

14. 11. The CT imaging system of claim 10, wherein the cooling sequence includes monitoring the remaining backup power of the UPS to determine whether the remaining backup power is sufficient to complete the cooling sequence.

15. 15. The CT imaging system of claim 14, wherein the gantry controller continues the cooling sequence if the remaining amount of backup power is sufficient to complete the cooling sequence.

16. 11. The CT imaging system of claim 10, wherein the x-ray tube includes a liquid metal bearing with a rotating assembly.

17. 11. The CT imaging system of claim 10, wherein the PDU controller is configured to send at least one signal to an X-ray controller to initiate the cool-down sequence to prevent hot shutdown of the X-ray tube.

18. 11. The CT imaging system of claim 10, wherein the gantry controller is configured to stop the CT imaging system from performing imaging scans upon detecting a loss of the main power supply.

19. 11. The CT imaging system of claim 10, further comprising, upon supplying backup power to the CT imaging system, displaying an indication of CT imaging system status and power availability on a display on an operator console coupled to the CT imaging system.

20. 1. A smart power method for protecting an x-ray tube in a CT imaging system during a power outage, comprising: monitoring the remaining amount of power from a backup power source provided by a UPS coupled to a PDU powering the CT imaging system; the x-ray tube having a liquid metal bearing rotating assembly; automatically determining where the remaining amount of backup power should be provided to prevent hot shutdown of the x-ray tube liquid metal bearing rotating assembly; A method comprising:

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