Detecting arc events within linear accelerator

Abstract

Methods and systems for detecting arc events within a linear accelerator are disclosed herein. An arc within the linear accelerator is detected using the reflected radio frequency power signal. This method can be automatically performed using components of the linear accelerator itself. The method includes obtaining a reflected radio frequency power signal, detecting an anomaly based on the reflected radio frequency power signal, the anomaly indicating an occurrence of an arc event, and outputting a signal indicating that the arc event has occurred.

Description

Technical Field

[0001] The embodiments of the invention described herein relate to methods and systems for detecting electric arc events within a radiotherapy linear accelerator (linac). More specifically, the invention relates to methods for detecting electric arc events within a radiotherapy linear accelerator, computer programs configured to perform said methods, and non-transient computer-readable media, as well as radiotherapy linear accelerator systems. Background Technology

[0002] Linear accelerators (LINACs) have wide applications in medicine and industry due to their ability to accelerate charged particles to high energies. In medicine, linear accelerators are crucial for treating deep-seated cancers through various forms of radiation therapy. In industry, linear accelerators are invaluable for non-destructive testing, sterilization, and supporting cutting-edge research in particle physics and other scientific disciplines. Radiation therapy can be described as treating a human or animal body using ionizing radiation (such as X-rays). Radiation therapy is commonly used to treat tumors in human or animal patients or subjects. In such treatments, ionizing radiation is used to irradiate and thereby destroy or damage the cells that form part of the tumor.

[0003] Linear accelerators are widely used in radiotherapy to precisely deliver high-energy X-rays or electron beams to tumors. Linear accelerators used in radiotherapy are highly complex machines with numerous intricately interacting subsystems. The beam generation module (BGM) is the subsystem used to generate the X-ray or electron beam. A BGM system includes a high-voltage generator (radio frequency (RF) modulator), a magnetron, RF wave propagation, an electron gun, and an accelerating waveguide. The RF modulator, electron gun, and magnetron operate at kilovolts, while the RF wave propagating in the waveguide may have a megavolt electric field. Different methods have been employed to avoid short circuits, such as vacuum and high-pressure isolation gas (SF6). However, electric arcing remains a common problem in BGM systems and can be caused by contamination on component surfaces, surface defects, component defects, component aging, poor vacuum quality, and / or misalignment between components. When electric arcing occurs, it can cause the linear accelerator to shut down or even damage components.

[0004] There is a need for improved methods and systems for detecting electric arcs inside linear accelerators. Summary of the Invention

[0005] The object of this invention is to at least partially address one or more of the challenges described above. Reference is now made to the independent claims, in which the invention is defined. Further features are set forth in the dependent claims.

[0006] According to a first aspect of the invention, a method for detecting an electric arc event within a radiotherapy linear accelerator (linac) is provided, the method comprising: obtaining a reflected radio frequency (RF) power signal; detecting an anomaly based on the reflected RF power signal, the anomaly indicating the occurrence of an electric arc event; and outputting a signal indicating that an electric arc event has occurred.

[0007] Several advantages are derived from embodiments based on the foregoing and the aspects described below. Advantages of embodiments of the invention include providing different ways to automatically detect electric arcs within a linear accelerator using components of the linear accelerator itself. This is advantageous because no additional monitoring equipment, such as an oscilloscope, is required. Furthermore, when monitoring signals from a linear accelerator using an oscilloscope, since this is done manually, a skilled engineer is needed to monitor the oscilloscope and manually mark any anomalies observed. This is also a subjective test, dependent on the engineer's skill and experience. In contrast, embodiments of the invention can be performed automatically using components within the linear accelerator. This means that no additional equipment or personnel are required to detect electric arcs, and the test is objective.

[0008] In some embodiments, the linear accelerator includes one or more modules, and the method is automatically executed by one or more modules of the linear accelerator.

[0009] In some embodiments, the anomaly indicating the occurrence of an arcing event is detected based on the amplitude of the reflected radio frequency power signal.

[0010] In some embodiments, the method further includes monitoring the average amplitude of the reflected radio frequency power signal, and wherein anomalies indicating the occurrence of an arcing event are detected based on the monitored average value.

[0011] In some embodiments, the method further includes monitoring the first-order difference of the reflected radio frequency power signal, wherein an anomaly indicating the occurrence of an arcing event is detected based on the monitored first-order difference.

[0012] In some embodiments, the method further includes: obtaining a forward radio frequency power signal; and obtaining a signal indicating the phase difference between the forward radio frequency power signal and the reflected radio frequency power signal; wherein an anomaly indicating the occurrence of an arc event is detected based on the signal indicating the phase difference.

[0013] In some embodiments, the method further includes monitoring the average amplitude of a signal indicating a phase difference, wherein anomalies indicating the occurrence of an arc event are detected based on the monitored average value.

[0014] In some embodiments, the method further includes: obtaining a forward radio frequency power signal; obtaining a signal indicating a phase difference between the forward radio frequency power signal and the reflected radio frequency power signal; and monitoring a first-order difference of the signal indicating the phase difference, wherein an anomaly indicating the occurrence of an arc event is detected based on the first-order difference.

[0015] In some embodiments, the first-order difference includes the difference between a signal indicating the phase difference at time n and a signal indicating the phase difference at time n-1.

[0016] In some embodiments, the method further includes inputting a reflected radio frequency power signal and a forward radio frequency power signal to a discriminator, the discriminator processing the reflected radio frequency power signal and the forward radio frequency power signal and outputting a first output signal and a second output signal; wherein the signal indicating the phase difference is obtained by calculating the difference between the second output signal and the first output signal.

[0017] In some embodiments, detecting an anomaly indicating the occurrence of an arc event in a signal indicating a phase difference includes: inputting a first output signal and a second output signal into a differential circuit to obtain a jump signal; and determining that the amplitude of the jump signal exceeds a predetermined threshold.

[0018] In some embodiments, an arcing event includes generating an arc in the radio frequency power transmission path of the linear accelerator.

[0019] In some embodiments, a signal indicating that an electric arc event has occurred is output to the user.

[0020] According to a second aspect, a computer program product including a computer-readable medium is provided, the computer-readable medium having computer-readable code embodied therein, the computer-readable code being configured to cause the computer or processor, when executed by a suitable computer or processor, to perform any of the above embodiments.

[0021] According to a third aspect, a non-transitory computer-readable storage medium is provided, comprising instructions that, when executed by a computer, cause the computer to perform any of the above embodiments.

[0022] According to a fourth aspect, a radiotherapy linear accelerator (linac) system is provided, comprising one or more modules, said one or more modules being configured together to perform the methods of any of the above embodiments.

[0023] According to a fifth aspect, a radiotherapy linear accelerator (linac) system is provided, comprising a system of one or more modules, the one or more modules being jointly configured to: acquire a reflected radiofrequency power signal; detect an anomaly based on the reflected radiofrequency power signal, the anomaly indicating the occurrence of an arcing event; and output a signal indicating that an arcing event has occurred.

[0024] In some embodiments, the one or more modules include a reflected radio frequency signal detector configured to obtain a reflected radio frequency power signal.

[0025] In some embodiments, the one or more modules further include a forward radio frequency signal detector configured to obtain a forward radio frequency power signal.

[0026] In some embodiments, the one or more modules further include a discriminator, an amplifier, and a controller; wherein the forward RF signal detector and the reflected RF signal detector are configured to send a forward RF power signal and a reflected RF power signal to the discriminator; the discriminator is configured to process the forward RF power signal and the reflected RF power signal, and output a first output signal and a second output signal; the amplifier is configured to calculate the difference between the second output signal and the first output signal to obtain a signal indicating the phase difference between the forward RF power signal and the reflected RF power signal, and output the signal indicating the phase difference to the controller; the controller is configured to detect an anomaly indicating the occurrence of an arcing event in the signal indicating the phase difference, and output a signal indicating that an arcing event has occurred.

[0027] In some embodiments, the one or more modules further include a differential circuit, wherein the differential circuit is configured to receive a first output signal and a second output signal from the discriminator and obtain a transition signal; and the controller is configured to receive the transition signal from the differential circuit and determine that the amplitude of the transition signal exceeds a predetermined threshold.

[0028] In some embodiments, the controller is a microcontroller unit (MCU).

[0029] In some embodiments, the controller is a beam generation controller for a linear accelerator.

[0030] Other features of the present invention are described below and set forth in the appended claims.

[0031] This invention can be implemented in digital electronic circuits, or in computer hardware, firmware, software, or a combination thereof. This invention can be implemented as a computer program or computer program product, i.e., a computer program tangibly embodied in a non-transitory information carrier, for example, in a machine-readable storage device or in a propagating signal, for execution by or control of the operation of one or more hardware modules.

[0032] A computer program can be a standalone program, a part of a computer program, or more than one computer program, and can be written in any programming language (including compiled or interpreted languages), and can be deployed in any form, including as a standalone program or as a module, component, subroutine, or other unit suitable for use in a data processing environment.

[0033] The invention has been described with reference to specific embodiments. Other embodiments are within the scope of the appended claims. For example, the steps of the invention can be performed in a different order and still achieve the desired result.

[0034] The elements of the present invention are described using terms such as "processor." Those skilled in the art will recognize that such functional terms and their equivalents can refer to parts of a system that are spatially separated but combined to serve the defined functions. Similarly, the same physical components of a system can provide two or more defined functions. For example, the same memory and / or processor can be suitably used to implement separately defined means. Attached Figure Description

[0035] Embodiments of the invention will now be further described by way of example only and with reference to the accompanying drawings, wherein the same reference numerals refer to the same parts, and wherein:

[0036] Figure 1 A radiotherapy system suitable for use with embodiments of the present invention is shown.

[0037] Figure 2 A radiotherapy system suitable for use with embodiments of the present invention is shown.

[0038] Figure 3 An exemplary beam generation module (BGM) for a linear accelerator suitable for use with embodiments of the present invention is shown.

[0039] Figure 4 An example of a component for monitoring reflected RF waves according to an embodiment of the present invention is shown.

[0040] Figure 5 Exemplary CT (magnetron current), CVD (magnetron voltage), electron gun current, and RF reflection waveforms are shown when no arc is generated.

[0041] Figure 6 Exemplary CT (magnetron current), CVD (magnetron voltage), electron gun current, and RF reflection waveforms are shown when an electric arc is generated.

[0042] Figure 7 This is an exemplary discriminator applicable to embodiments of the present invention.

[0043] Figure 8 An example of a typical AFC error curve is shown.

[0044] Figure 9 An example of a component for monitoring phase difference according to an embodiment of the present invention is shown.

[0045] Figure 10 Exemplary AFC A, AFC B, and (AFC A-AFC B) signals are shown when an electric arc is generated.

[0046] Figure 11 Exemplary AFC A, AFC B, and (AFC A-AFC B) signals are shown when intentional incoordination occurs.

[0047] Figure 12 An example of a component for obtaining a transition signal according to an embodiment of the present invention is shown.

[0048] Figure 13 This is a flowchart of a method for detecting electric arc events within a linear accelerator according to an embodiment of the present invention.

[0049] Figure 14 This is a flowchart of a method for detecting electric arc events within a linear accelerator according to an embodiment of the present invention.

[0050] Figure 15 This is a flowchart of a method for detecting electric arc events within a linear accelerator according to an embodiment of the present invention.

[0051] Figure 16 This is a flowchart of a method for detecting electric arc events within a linear accelerator according to an embodiment of the present invention.

[0052] Figure 17 This is a flowchart of a method for detecting electric arc events within a linear accelerator according to an embodiment of the present invention. Detailed Implementation

[0053] Overview

[0054] Embodiments of the present invention provide different ways to automatically detect electric arcs within a linear accelerator using components that are already part of the linear accelerator itself. This is advantageous because no additional monitoring equipment (e.g., an oscilloscope) is required. Furthermore, when using an oscilloscope to monitor signals from a linear accelerator (which is done manually), a skilled engineer is needed to monitor the oscilloscope and manually flag any anomalies observed. Conversely, embodiments of the present invention can be automated using a discriminator and BGC that are already components within the linear accelerator. This means that no additional equipment or personnel are required to detect electric arcs. The first method involves monitoring the amplitude of the reflected RF signal. The second method involves monitoring the amplitude of the phase difference signal (derived from the forward and reflected RF signals). The third method involves monitoring d(n) - d(n-1), which can be referred to as the first-order difference, where d is the phase difference signal and n represents time. Thus, all three methods provide a way to detect electric arcs using reflected RF signals.

[0055] The following will refer to Figures 1 to 16 Describe the various aspects and details of these main concepts.

[0056] Radiotherapy system

[0057] Figure 1 A radiotherapy system or device suitable for delivering a radiation beam to a patient during radiotherapy and configured to do so is illustrated. To provide useful accompanying information about the invention, the device and its constituent parts will be generally described. Figure 1 The device shown is according to the invention and is suitable for use with the disclosed methods and systems. Although Figure 1 The device mentioned is an MR linear accelerator (magnetic resonance linear accelerator), but the present invention can be implemented using any linear accelerator (linac) device.

[0058] Figure 1 The device 100 shown is an MR linear accelerator. Device 100 includes an MR imaging unit 112 and a radiotherapy (RT) unit, which may include the linear accelerator device. The MR imaging unit 112 is shown in a partially obliterated perspective view in the figure. In operation, the MR scanner produces MR images of the patient, and the linear accelerator device generates and shapes a radiation beam, directing it to a target area within the patient's body according to the radiotherapy plan. Figure 1 The typical “casing” is not shown, which would cover MR imaging device 112 and RT device in a commercial environment such as a hospital.

[0059] Figure 1The illustrated MR linear accelerator device includes a radio frequency (RF) source 102, a waveguide 104, an electron source 106, a radiation source 103, a collimator 108 (e.g., a multi-leaf collimator) configured to collimate and shape the beam, an MR imaging unit 112 (shown partially obliterated), and a patient support surface 114. In use, the device will also include a housing (not shown) that defines an aperture together with a ring-shaped stage. The patient support surface 114 is movable and can be used to support a patient and move a patient or another subject into the aperture during MR scanning and / or initiation of radiotherapy. The MR imaging unit 112, the RT unit, and the patient support surface actuator are communicatively coupled to a controller or processor. The controller is also communicatively coupled to a storage device including computer-executable instructions that can be executed by the controller (see description below). Figure 2 In the following text, the controller may be referred to as the beam generation controller (BGC).

[0060] The RT device includes a radiation source 103 and a radiation detector (not shown). Typically, the radiation detector is positioned relative to the diameter of the radiation source 103. The radiation detector is adapted and configured to generate radiation intensity data. Specifically, the radiation detector is positioned and configured to detect the intensity of radiation passing through the subject. The radiation detector can also be described as a radiation detection device and can form part of a radiation field imaging system.

[0061] Radiation source 103 may include a beam generation module (BGM) or system. The following will refer to... Figure 3 The layout of the BGM is described in more detail. For a linear accelerator, the beam generation system may include an RF wave source 102, an electron source 106 (e.g., an electron gun (or e-gun)), and a waveguide 104. A radiation source 103 is attached to a rotatable gantry 116 so that it rotates together with the gantry 116. Thus, the radiation source 103 can rotate around the patient, allowing the treatment beam 110 to be applied from different angles around the gantry 116. In a preferred implementation, the gantry is continuously rotatable. In other words, the gantry can rotate 360 ​​degrees around the patient, and in fact, can continue to rotate beyond 360 degrees. The gantry may be annular. In other words, the gantry may be a toroidal gantry.

[0062] For example, the magnetron's radio frequency (RF) source 102 is configured to generate RF waves. The RF source 102 is coupled to waveguide 104 via a circulator 118 and is configured to pulse the RF wave into waveguide 104. The RF wave can travel from the RF source 102 through the RF input window and into the RF input connection pipe or tube. An electron source 106 is also coupled to waveguide 104 and is configured to inject electrons into waveguide 104. In electron source 106, electrons are thermionicly emitted from the cathode filament when the filament is heated. The filament temperature controls the number of injected electrons. The electron injection into waveguide 104 is synchronized with the pumping of the RF wave into waveguide 104. The design and operation of the RF source 102, electron source 106, and waveguide 104 enable the RF wave to accelerate electrons to very high energies as they propagate through waveguide 104.

[0063] The design of waveguide 104 depends on whether the linear accelerator uses standing waves or traveling waves to accelerate electrons, but waveguides typically comprise a series of cells or cavities connected by apertures or "iris" through which the electron beam can pass. The cavities are coupled to generate a suitable electric field pattern that accelerates electrons propagating through waveguide 104. As electrons are accelerated in waveguide 104, the electron beam path is controlled by a suitable arrangement of manipulating magnets or manipulating coils surrounding waveguide 104. The arrangement of manipulating magnets may include, for example, two sets of quadrupole magnets.

[0064] Once the electrons are accelerated, they can enter the flight tube. The flight tube can be connected to the waveguide via a connecting tube. This connecting tube or connection structure can be referred to as a drift tube. The electrons travel towards a heavy metal target, which may include, for example, tungsten. As the electrons travel through the flight tube, an arrangement of focusing magnets is used to guide and focus the beam onto the target.

[0065] To ensure that electron propagation is not impeded as the electron beam travels toward the target, a vacuum system, including a vacuum pump or an arrangement of vacuum pumps, is used to evacuate the waveguide 104. The pump system is capable of generating ultra-high vacuum (UHV) conditions in the waveguide 104 and the flight tube. The vacuum system also ensures UHV conditions in the electron gun. Electrons can be accelerated to speeds approaching the speed of light in the evacuated waveguide 104.

[0066] Radiation source 103 is configured to guide a therapeutic beam 110 of therapeutic radiation onto a patient positioned on a patient support surface 114. Therefore, radiation source 103 can also be referred to as a therapeutic radiation source. Radiation source 103 may include a heavy metal target, from which high-energy electrons leaving the waveguide are directed. When the electrons strike the target, X-rays are generated in various directions. A primary collimator can block X-rays traveling in certain directions and allow only forward-traveling X-rays to pass through to generate the therapeutic beam 110. The X-rays can be filtered and can pass through primary and secondary ionization chambers for dose measurement. Before the beam enters the patient as part of radiotherapy, it can be shaped in various ways by a beamforming device, such as by using a multi-leaf collimator 108.

[0067] In some implementations, the radiation source 103 is configured to emit either an X-ray beam or an electron particle beam. This implementation allows the device to provide electron beam therapy, i.e., an external beam therapy that directs electrons, rather than X-rays, towards a target region as therapeutic radiation. By adjusting components of the linear accelerator, a first mode of emitting X-rays can be “switched” between a second mode of emitting electrons. Essentially, switching between the first and second modes is achieved by moving the heavy metal target into or out of the electron beam path and replacing it with a so-called “electron window.” The electron window is substantially transparent to the electrons and allows them to exit the flight tube.

[0068] A subject or patient support surface is configured to move between a first position generally outside the aperture and a second position generally inside the aperture. In the first position, the patient or subject can mount the patient support surface. The patient support surface 114 and the patient can then move inside the aperture to the second position to image the patient via MR imaging device 112 and / or to image or treat the patient using RT device. Thus, the aperture can be located around a portion of a space suitable for receiving a patient—a portion of the patient receiving space. The movement of the patient support surface is achieved and controlled by a patient support surface actuator, which can be described as an actuation mechanism. These components together can be described as a patient positioning system, which may include other components. The actuation mechanism is configured to move the patient support surface in a direction parallel to and defined by the central axis of the aperture. The terms “subject” and “patient” are used interchangeably herein, such that the patient support surface can also be described as a subject support surface. The patient support surface can also be referred to as a movable or adjustable examination table or worktable.

[0069] Figure 1The illustrated radiotherapy apparatus / device also includes an optional MR imaging unit 112. The MR imaging unit 112 is configured to acquire images of a subject positioned (i.e., located on) a patient support surface. The MR imaging unit 112 may also be referred to as an MR imager. The MR imaging unit 112 can be a conventional MR imaging device that operates in a known manner to acquire MR data (e.g., MR images). Those skilled in the art will understand that such an MR imaging unit 112 may include a main magnet, one or more gradient coils, one or more receiving coils, and an RF pulse applicator. The operation of the MR imaging unit is controlled by a controller.

[0070] The controller is a computer, processor, or other processing device. The controller may be formed from several discrete processors; for example, the controller may include: an MR imaging device processor that controls the MR imaging device 112; an RT device processor (which may be hereinafter referred to as a beam generation controller (BGC)) that controls the operation of the RT device; and a patient support surface processor that controls the operation and actuation of the patient support surface. The controller is communicatively coupled to a memory (e.g., a computer-readable medium). The controller may be combined with the following... Figure 2 The computing system 210 is described.

[0071] Linear accelerator equipment also includes several other components and systems as those skilled in the art will understand. For example, appropriate shielding is provided to ensure that the linear accelerator does not leak radiation.

[0072] Each time a radiation therapy dose is administered to a patient positioned on a patient support surface, one or more trigger signals cause the radiation source to emit a radiation dose. One or more trigger signals are simultaneously provided to multiple parts of the radiation therapy system 100 to activate it. The simultaneously triggered parts of the radiation therapy system 100 may include a magnetron and an electron gun. Simultaneously triggering the various parts of the radiation therapy system 100 will also trigger multiple observable pulse signals to evaluate the performance of the radiation therapy system. Examples of such observable pulse signals include: magnetron current signal (CT), magnetron voltage signal (CVD), electron gun current signal, RF forward power signal, RF reflected power signal, primary ionization chamber current, and secondary ionization chamber current. These simultaneously triggered signals will have a common nominal pulse width (e.g., 5 μS), and the nominal pulse width can be used to determine the data capture window used to capture data associated with a given pulse. As an example, the data capture window may be slightly larger than the nominal pulse width to ensure that all data associated with a given pulse can be captured.

[0073] The radiotherapy system 100 can be operated according to the order or sequence of synchronously triggered pulse groups, wherein each different type of pulse signal within the group is synchronously triggered at the same repetition frequency.

[0074] Computing System

[0075] Figure 2 This is a block diagram of a radiotherapy system 200 adapted to perform the methods according to embodiments. The exemplary radiotherapy system 200 includes a computing system 210 within which a set of instructions can be executed to cause the computing system 210 to perform the methods (or steps thereof) discussed herein. The computing system 210 may optionally implement an image reconstruction system. The computing system 210 may also be referred to as a computer. Specifically, the methods described herein may be implemented by the processor or controller circuitry 211 of the computing system 210.

[0076] The computing system 210 should be considered to include any number or set of machines, such as one or more computing devices that individually or jointly execute a set (or more) of instructions to implement any of the methods discussed herein. That is, the hardware and / or software may be provided in a single computing device or distributed across multiple computing devices in the computing system. In some implementations, one or more elements of the computing system may be connected (e.g., networked) to other machines, such as in a local area network (LAN), intranet, extranet, or the Internet. One or more elements of the computing system may operate as a server or client machine in a client-server network environment, or as a peer machine in a peer-to-peer (or distributed) network environment. One or more elements of the computing system may be a personal computer (PC), tablet computer, set-top box (STB), personal digital assistant (PDA), cellular phone, network device, server, network router, switch, or bridge, or any machine capable of executing a set of instructions (sequential or otherwise) specifying the actions to be taken by that machine.

[0077] The computing system 210 includes controller circuitry 211 and memory 213 (e.g., read-only memory (ROM), flash memory, dynamic random access memory (DRAM), such as synchronous DRAM (SDRAM) or RAM bus DRAM (RDRAM). Memory 213 may include static memory (e.g., flash memory, static random access memory (SRAM), etc.) and / or auxiliary memory (e.g., data storage devices) that communicate with each other via a bus (not shown).

[0078] Controller circuit 211 represents one or more general-purpose processors, such as microprocessors, central processing units, accelerated processing units, etc. More specifically, controller circuit 211 may include complex instruction set computing (CISC) microprocessors, reduced instruction set computing (RISC) microprocessors, very long instruction word (VLIW) microprocessors, processors implementing other instruction sets, or processors implementing combinations of instruction sets. Controller circuit 211 may also include one or more special-purpose processing devices, such as application-specific integrated circuits (ASICs), field-programmable gate arrays (FPGAs), digital signal processors (DSPs), network processors, etc. One or more processors of the controller circuit may have a multi-core design. Controller circuit 211 is configured to execute processing logic for implementing the operations and steps discussed herein.

[0079] The computing system 210 may also include network interface circuitry 215. The computing system 210 may be communicatively coupled to input device 220 and / or output device 230 via input / output circuitry 216. In some implementations, input device 220 and / or output device 230 may be elements of the computing system 210. Input device 220 may include alphanumeric input devices (e.g., keyboard or touchscreen), cursor control devices (e.g., mouse or touchscreen), audio devices (e.g., microphone), and / or haptic input devices. Output device 230 may include audio devices and / or haptic output devices, such as speakers, video display units (e.g., liquid crystal display (LCD) or cathode ray tube (CRT)). In some embodiments, input device 220 and output device 230 may be provided as a single device or as separate devices.

[0080] In some implementations, the computing system 210 may include image processing circuitry 214. Image processing circuitry 214 may be configured to process image data 270 (e.g., images, imaging data, projections, projection data), such as medical images obtained from one or more imaging data sources, treatment devices 250, and / or image acquisition devices 240. Image processing circuitry 214 may be configured to process or preprocess image data 270. For example, image processing circuitry 214 may convert received image data into a specific format, size, resolution, etc.

[0081] In some embodiments, the radiotherapy system 200 may further include an image acquisition device 240 and / or a treatment device 250. The image acquisition device 240 and the treatment device 250 may be provided as a single device, for example, regarding the above. Figure 1 The system 100 is described. In some implementations, the treatment device 250 is configured to perform imaging, for example, in addition to providing treatment and / or during treatment.

[0082] The image acquisition device 240 can be configured to perform positron emission tomography (PET), computational tomography, magnetic resonance imaging (MRI), single positron emission tomography (SPECT), X-ray, etc.

[0083] Image acquisition device 240 can be configured to output image data 270, which can be accessed by computing system 210. Treatment device 250 can be configured to output treatment data 260, which can be accessed by computing system 210. Treatment data 260 can be obtained from an internal data source (e.g., from memory 213) or from an external data source (e.g., treatment device 250 or an external database).

[0084] The various methods described below can be implemented by a computer program. A computer program may include computer code (e.g., instructions) arranged to instruct a computer to perform one or more of the methods described below. For example, the following regarding... Figures 13 to 16 The steps of the methods described in any of the above can be executed by computer code. The steps of the methods described below can be performed in any suitable order. The computer program and / or code for performing this method can be provided on one or more computer-readable media or more generally on a computer program product to a device such as a computer. The computer-readable media can be transient or non-transient. One or more computer-readable media can be, for example, electronic, magnetic, optical, electromagnetic, infrared, or semiconductor systems, or propagation media for data transmission, such as for downloading code over the Internet. Alternatively, one or more computer-readable media can take the form of one or more physical computer-readable media such as semiconductor or solid-state memory, magnetic tape, removable computer floppy disk, random access memory (RAM), read-only memory (ROM), rigid disk, and optical disk (such as CD-ROM, CD-R / W, or DVD). During execution by computing system 210, the instructions can also reside wholly or at least partially in memory 213 and / or controller circuitry 211, which also constitute computer-readable storage media.

[0085] In one implementation, the modules, components, and other features described herein may be implemented as discrete components or integrated into the functionality of hardware components such as ASICs, FPGAs, DSPs, or similar devices.

[0086] A "hardware component" is a tangible (e.g., non-transitory) physical component (e.g., one or more processor groups) capable of performing a specific operation and which can be configured or arranged in a specific physical manner. A hardware component may include dedicated circuitry or logic permanently configured to perform certain operations. A hardware component may include dedicated processors, such as FPGAs or ASICs. A hardware component may also include programmable logic or circuitry temporarily configured by software to perform certain operations.

[0087] Furthermore, modules and components can be implemented as firmware or functional circuitry within a hardware device. Additionally, modules and components can be implemented as any combination of hardware devices and software components, or solely as software (e.g., code stored or otherwise embodied in a machine-readable medium or in a transmission medium).

[0088] Unless otherwise stated, it will be clear in the following discussion that throughout the description, the use of terms such as “detect,” “receive,” “transform,” “extract,” “obtain,” “determine,” “enable,” “hold,” “identify,” “input,” and “output” refers to the actions and processes of a computer system or similar electronic computing device that manipulate and convert data representing physical (electronic) quantities in the registers and memory of the computer system into other data representing physical quantities in the memory or registers or other information storage, transmission, or display devices of the computer system.

[0089] BGM system

[0090] As mentioned above Figure 1 The radiation source 103 of the radiotherapy system 100 described herein may include a beam generator (BGM). The BGM is responsible for generating and delivering an electron beam or X-ray beam for radiotherapy. A simplified BGM structure is shown below. Figure 3 As shown and described below, the BGM system 300 includes various components, each playing a crucial role in the generation, acceleration, control, and delivery of the particle beam. These components are described below.

[0091] Radio frequency (RF) modulator 302 is arranged to provide an initial pulse to RF power source 304 (e.g., magnetron), and each pulse can sequentially trigger RF power source 304 to output or transmit a corresponding subsequent RF pulse to circulator 308.

[0092] It should be understood that each “initial pulse” described herein can be a pulse signal and can correspond to a voltage signal pulse or other electrical pulse. Such pulses can therefore be used to control the operation of components such as RF power sources and accelerating waveguides. For example, an RF power source can be triggered or modulated by a received initial pulse to output an RF power pulse to an accelerating waveguide corresponding to the duration of the received initial pulse. This pulse signal has a nominal pulse width (e.g., 5 μs) in the time domain corresponding to the operational requirements of the wave generation subsystem. Therefore, in an example using a 5 μs pulse width, a 5 μs electrical pulse can be generated by RF modulator 302 and provided to RF power source 304, which can then output a pulse of RF power with a duration of 5 μs. The RF power source can operate repeatedly in this manner and can therefore output pulses according to the pulse repetition frequency (PRF). A typical PRF value for a radiotherapy system is 275 Hz, although other values ​​can be used depending on system requirements.

[0093] RF modulator 302 may be arranged to time-modulate or control the output of RF power source 304. For example, RF modulator 302 may be arranged to generate initial pulses at a specific frequency (pulse repetition frequency) and provide these pulses to RF power source 304; then, RF power source 304 will generate subsequent RF pulses according to the pulse repetition frequency, each pulse having appropriate power or energy for powering the accelerating waveguide 310 of the beam generation subsystem. In some examples, the initial pulse may be a pulse of RF energy or power and may also be amplified by RF power source 304. In some examples, the initial pulse is a non-RF electrical signal.

[0094] Circulator 308 is arranged to transmit subsequent RF pulses from RF power source 304 to accelerating waveguide 310 of the linear accelerator. Therefore, circulator 308 provides a passive transmission component between RF power source 304 and accelerating waveguide 310. It should be understood that RF modulator 302, RF power source 304, circulator 308, and accelerating waveguide 310 can each be coupled to, for example, via any suitable RF transmission medium (e.g., a waveguide). Figure 3One or more adjacent RF components are shown. As is known to those skilled in the art, circulators typically used in radiotherapy have four ports, and these ports are arranged in a manner appropriate for the beam generation subsystem. For example, one port may be arranged to receive RF power from RF power source 304, while another port will be arranged to output RF power to accelerating waveguide 310, and the other two ports may be connected to, for example, a water load and a dry load, respectively. It should be understood that in some examples, a circulator with a different number of ports than four may be used as circulator 308. Accelerating waveguide 310 uses radio frequency power / energy to accelerate electrons from an electron gun (not shown). The accelerated electrons are then directed to a target (not shown). At the target, the kinetic energy of the electrons is converted into other forms of energy (e.g., X-rays) for medical or industrial applications.

[0095] RF modulator 302 can be controlled by an RF trigger signal received from a controller, which may be referred to as beam generation controller (BGC) 314. BGC 314 monitors and manages system 300. BGC 314 interacts with various subsystems to control parameters, monitor performance, and ensure safety. BGC 314 can perform one or more steps of methods 1300, 1400, 1500, 1600, and 1700 described below. BGC 314 can receive input from and send output to a real-time computer (not shown). This real-time computer can be connected to a control PC including a web GUI. The web GUI allows engineers or users to view the output of BGC 314 and input user input.

[0096] BGC 314 can also manage the generation of the electron beam. The BGC can cooperate with an electron gun modulator (not shown) to generate a precise and stable electron stream. The electron gun modulator provides the high-voltage pulses required to extract electrons from the electron gun (not shown). The electron gun modulator ensures precise timing and control of electron emission. The electron gun generates electrons that are subsequently accelerated in the accelerating waveguide 310. The electron gun can include a thermionic or photocathode type, emitting electrons when heated or exposed to light.

[0097] Discriminator 312, such as an Automatic Frequency Control (AFC) discriminator, can receive reflected RF signals from circulator 308. Discriminator 312 can also receive forward RF signals from RF power source 304. Discriminator 312 maintains the stability of the magnetron RF frequency to ensure that the RF energy is maintained at the optimal frequency of accelerating waveguide 346 based on the forward and reflected RF signals. Discriminator 312 can output a phase difference signal back to BGC 314. The operation of discriminator 312 is described in more detail below. Tuner driver 306 can be connected to RF power source 304. Tuner driver 306 tunes the frequency of RF power source to the resonant frequency of the accelerator to compensate for thermal and other variations to maintain optimal operation (described in more detail below). Tuner driver 306 can receive tuner control signals from BGC 314.

[0098] An electric arc may occur in the RF power source 304 or the RF power transmission path (the components and paths involved in transmitting radio frequency energy from the RF power source 304 (e.g., a magnetron) to the acceleration structure (acceleration waveguide 310)).

[0099] Referring to the exemplary AFC module 700 shown Figure 7 Let's explain the example of discriminator 312 in more detail. Module 700 receives a forward RF signal 702 and a reflected RF signal 704. The forward signal 702 passes through a phase shifter 706, a delay line 708, and a first low-pass (LP) filter 710. The reflected signal 704 passes through a second low-pass filter 712. The two signals are then coupled using a coupler 714. The reflected signal 704 passes through a first diode 716 to form a first output signal 720. The forward signal 702 passes through a second diode 718 to form a second output signal 722. The first output signal 720 may be referred to as AFC A. The second output signal 722 may be referred to as AFC B. The difference error signal AFC B - AFC A is proportional to the phase difference between the RF signals 702 and 704. Typically, discriminator 312 takes the forward RF signal from RF power source 304 and the reflected RF signal from circulator 308 and outputs two output signals. The difference between these output signals can be determined to give a difference error signal that is proportional to the phase difference of the RF signal.

[0100] Figure 8An example of a typical AFC error curve 800 is shown. The X-axis is the frequency difference between the magnetron (forward RF signal) and the accelerator frequency (reflected RF signal), and the Y-axis is the difference error signal AFC B – AFC A generated by the AFC module 700. It can be seen that the difference error signal is proportional to the phase difference between the two RF input signals. Therefore, the difference error signal forms a reliable control variable. This difference error signal can be used to tune the magnetron frequency to the accelerator's resonant frequency. This means that if the magnetron's RF frequency operates at the accelerator's resonant frequency, then AFC B – AFC A is approximately zero. Otherwise, AFC B – AFC A is proportional to the phase difference between the magnetron frequency (forward RF signal) and the accelerator frequency (reflected RF signal).

[0101] As described above, the discriminator 312 is part of the linear accelerator system. The discriminator (e.g., AFC) receives the reflected RF signal and can therefore act as or include a reflected RF detector. Figure 4 As shown, the reflected RF detector 402 receives the reflected radio frequency (analog) signal and sends it to attenuator 404, then diode 406, and then differential amplifier 408 to convert the single-ended reflected RF signal into a differential reflected RF signal. A differential analog-to-digital converter (ADC) 410 then converts the differential signal into a digital signal. In this way, the attenuator and diode can be used to sample the RF reflected wave, converting the analog reflected RF signal into a digital RF signal. The digital RF signal can be sent to an MCU (microcontroller unit), which can form part of the BGC 314. The MCU can then monitor the reflected RF signal to detect arcing events.

[0102] A feasible example of such a discriminator 312 is the AFT microwave mAFC-2998-01. A feasible example of such a diode 406 is the Keysight 8470B diode. A feasible example of such an amplifier 408 is the Analog Devices LTC6362 amplifier, a low-power, low-noise differential operational amplifier with rail-to-rail input and output swing, optimized to drive a low-power SAR ADC (Successive Approximation Register ADC). Amplifier 408 can convert a single-ended signal into a differential signal, which can then be input to a high-speed analog-to-digital converter. A feasible example of such an analog-to-digital converter 410 is the Analog Devices AD9228 analog-to-digital converter, a four-channel, differential-input, 12-bit, 40-65 MSPS ADC. It can acquire 40 million samples per second, so that the conversion rate is sufficient to monitor arcs. However, it should be understood that any suitable linear accelerator module (e.g., discriminator, diode, amplifier, and ADC) can be used to implement embodiments of the invention.

[0103] Arc detection

[0104] In linear accelerator systems (e.g., Figure 1 and Figure 3 In the system shown and described above, common pulse signals include:

[0105] • Upstream pulse signals: Magnetron voltage (CVD) and magnetron current (CT);

[0106] • Midstream pulse signals: forward RF power, reflected RF power, electron gun current, phase detector differential voltage; and

[0107] Downstream pulse signals: primary dose current and secondary dose current.

[0108] Common non-pulse signals include:

[0109] • Accelerator waveguide vacuum level indicated by ion pump current; and

[0110] • Readings from various sensors, including temperature, cooling water flow rate, SF6 pressure, etc.

[0111] These pulse signals can be represented by waveforms. A "waveform" is a graphical representation of an electrical signal that changes over time. Figure 5 Exemplary CT, CVD, electron gun current, and RF reflection waveforms are shown when no arc is generated, i.e., the waveforms should look like when the linear accelerator is operating normally. Figure 5 The CVD waveform 502, RF reflection waveform 504, CT waveform 506, and electron gun current waveform 508 are shown. In the example shown, the RF reflection waveform 504 includes an envelope of 2998 mHz and a pulse width of approximately 4 μs. Figure 6 This illustrates how signals 502, 504, 506, and 508 change when an electric arc is generated. The reflected RF signal 504 changes significantly when an electric arc is generated. This signal 504 can be sampled using a high-speed analog-to-digital converter, for example, as shown in the reference above. Figure 4 As described, it monitors the average value of the radio frequency reflected waveform. This allows for the identification of electric arcs. Figure 5 and Figure 6 The horizontal x-axis represents time, and each square corresponds to 1 ms.

[0112] Figure 9 This illustrates how phase differences (e.g., AFC B – AFC A or AFC A – AFC B, depending on the output definition) can be used for arc detection. Discriminators 312, 902, and 700 receive the forward and reflected RF signals and output two signals (e.g., AFC A and AFC B signals), as referenced above. Figure 7The amplifier 904, such as amplifier 408, generates a phase difference signal d = AFC B – AFC A (or AFC A – AFC B). The phase difference signal d is then input to an analog-to-digital converter (ADC) 906 for outputting a digitized phase difference signal. The digitized phase difference signal is input to a microcontroller (MCU) 908, which can form part of BGC 314. MCU 908 provides two functions. First, MCU 908 outputs a signal to tuner 910 (e.g., tuner driver 306) to tune the magnetron 912 frequency to the accelerator's resonant frequency, making the phase difference signal as close to zero as possible. Second, MCU 908 monitors the phase difference signal to detect arcing events. This is accomplished by monitoring d(n) – d(n-1), where d is the phase difference signal, and d is set to d(0) when time t = 0. When t = 1, d = d(1), until t = (n-1), d = d(n-1) and t = n, d = d(n).

[0113] Figure 10 The diagram shows AFC A 1004, AFC B 1002, and (AFC A–AFC B) 1006 when an electric arc is generated. It can be seen that (AFC A–AFC B) 1006 changes significantly due to the phase difference. Using signal 1006, for example by sampling signal 1006 using a high-speed ADC, an electric arc can be identified.

[0114] Embodiments of the present invention provide different methods for automatically detecting electric arcs within a linear accelerator using components of the linear accelerator itself. Embodiments of the present invention can be performed automatically using the discriminator 312 and BGC 314. Examples of methods for automatically identifying electric arcs using linear accelerator components are listed below.

[0115] First, the arc can be identified by monitoring the amplitude of the reflected RF signal. The reflected RF signal can be sampled using an attenuator and a diode, and then monitored by a BGC 314, as mentioned above. Figure 4 As described below. Figure 14 Describe this example.

[0116] Secondly, an electric arc can cause a phase difference between the forward and reflected RF waves, resulting in an amplitude change in the phase difference signal (AFC A – AFC B). The arc can be identified by monitoring the amplitude (or average amplitude) of the phase difference signal. The following section combines... Figure 15 Describe this example. However, in some cases, the incoordination between the forward and reflected waves may be intentional (rather than caused by the electric arc). For example... Figure 11 As shown, this intentional inconsistency can also cause changes in the average value of the phase difference signal. Figure 11The diagram shows AFC A 1004, AFC B 1002, and (AFC A–AFC B) 1006 when an intentional dissonance occurs. It can be seen that (AFC A–AFC B) 1006 changes significantly compared to its baseline. To distinguish between arcing and intentional dissonance, a differential circuit can be used to collect the transition signal. An example of such a differential circuit is shown below. Figure 12 As shown. Figure 12 The signals AFC A and AFC B (i.e., from the discriminators 312, 700, and 902 as described above) are shown as input to the differential circuit 1202 to generate transition signals. The transition signals are then processed by the differential analog-to-digital converter 1204 (e.g., analog-to-digital converters 410 and 906 as described above) and output to the MCU 1206 (e.g., MCU 908 as described above). When the output amplitude of the differential circuit (i.e., the amplitude of the transition signal) exceeds a predetermined threshold, an arc can be identified as the cause of the phase difference. On the other hand, intentional incoordination is a stable signal with a zero transition signal.

[0117] Third, MCU firmware (microcontroller firmware) can be used to process... Figure 9 The analog-to-digital converter 906 shown samples the raw data without requiring differential circuitry to distinguish between intentional inconsistencies and arcs. The following section combines... Figure 16 Describe this example. This means that d(n) – d(n-1) can be monitored instead of the average value of the phase difference signal. In this way, the MCU FW can distinguish between the phase difference caused by intentional mismatch between the forward and reflected waves and the phase difference caused by an electric arc. When no electric arc is generated, such as during intentional mismatch, d(n) – d(n-1) is approximately zero. However, when an electric arc is generated, d(n) – d(n-1) is greater than zero. A predetermined threshold can be set to automatically determine whether an electric arc has been generated. For example, the threshold can be set to 0.5V. If d(n) – d(n-1) > 0.5V, the system can infer that an electric arc has been generated. If d(n) – d(n-1) < 0.5V, the system can infer that no electric arc has been generated.

[0118] Figure 13 This is a flowchart illustrating the processing steps in method 1300 for detecting an electric arc event within a radiotherapy linear accelerator. Method 1300 can be executed automatically by one or more modules of the linear accelerator (e.g., BGC 314, discriminator 312, amplifiers 408, 904, etc.).

[0119] In step 1302, method 1300 includes obtaining the reflected RF power signal. This step can be performed using a reflected RF signal detector, as described above. Figure 4As described. In some examples, the reflected RF signal detector can be configured to send the reflected RF power signal to the discriminator 312 and / or the controller (e.g., the MCU and / or the BGC 314).

[0120] In step 1304, method 1300 includes detecting an anomaly based on the reflected RF power signal, which indicates the occurrence of an arcing event. For example, the anomaly indicating the occurrence of an arcing event can be detected based on the amplitude of the reflected RF power signal itself, the average value of said amplitude, other signals derived from the reflected RF power signal (e.g., the aforementioned phase difference signal (phase difference) or the aforementioned d(n)–d(n-1) signal), etc. In some examples, step 1304 is performed by the MCU and / or BGC 314.

[0121] In step 1306, method 1300 includes outputting a signal indicating that an arcing event has occurred. In some examples, step 1306 is performed by the MCU and / or BGC 314. In some examples, the signal is output to a user, for example, via a web GUI. An arcing event may include an arc in the RF power delivery path of the linear accelerator.

[0122] Figure 14 This is a flowchart illustrating the processing steps in method 1400 for detecting an electric arc event within a radiotherapy linear accelerator. Method 1400 can be executed automatically by one or more modules of the linear accelerator (e.g., BGC 314, discriminator 312, amplifiers 408, 904, etc.).

[0123] Method 1400 includes steps 1302, 1403, 1404, and 1306. Steps 1302 and 1306 have been described above.

[0124] Step 1402 includes monitoring the average amplitude of the reflected RF power signal. This may include calculating the average value of the signal over a specific time window. This can be done using a moving average filter or by summing the amplitude values ​​and dividing by the number of amplitude values.

[0125] Step 1404 includes detecting an anomaly based on the monitored average value, which indicates the occurrence of an arcing event. For example, if the average value exceeds a predetermined threshold, an arcing event can be considered detected.

[0126] Figure 15 This is a flowchart illustrating the processing steps in method 1500 for detecting an electric arc event within a radiotherapy linear accelerator. Method 1500 can be executed automatically by one or more modules of the linear accelerator (e.g., BGC 314, discriminator 312, amplifiers 408, 904, etc.).

[0127] Method 1500 includes steps 1302, 1504, 1506, and 1306. Steps 1302 and 1306 have been described above.

[0128] Step 1502 includes obtaining a forward RF power signal. This step can be performed by a forward RF signal detector positioned after the magnetron. The forward RF signal detector can be connected from a coupler (e.g., a non-directional coupler) positioned after the magnetron. In some examples, the forward RF signal detector can be configured to send a forward RF power signal to discriminator 312 and / or controller (e.g., MCU and / or BGC 314).

[0129] Step 1504 includes obtaining a signal indicating the phase difference between the forward RF power signal and the reflected RF power signal. In some examples, a discriminator 312 (e.g., AFC module 700) can be used to obtain the signal indicating the phase difference. In this case, the reflected RF power signal and the forward RF power signal are sent to the discriminator (in some examples, via a reflected and forward RF signal detector), which processes the reflected and forward RF power signals and outputs a first output signal and a second output signal (e.g., AFC A and AFC B mentioned above). The signal indicating the phase difference can then be obtained by calculating the difference between the second output signal and the first output signal (e.g., AFC B – AFC A). This difference calculation can be performed by an amplifier (e.g., amplifiers 408, 904). The amplifier can output the signal indicating the phase difference to a controller (e.g., BGC314, MCU 908). The controller can be configured to detect anomalies.

[0130] In some examples, method 1500 also includes monitoring the average amplitude of the signal indicating a phase difference. In this case, anomalies indicating the occurrence of an arcing event can be detected based on the monitored average. Monitoring the average may include calculating the average of the signal over a specific time window. This can be done using a moving average filter or by summing the amplitude values ​​and dividing by the number of amplitude values.

[0131] Step 1506 includes detecting an anomaly based on a signal indicating a phase difference, the anomaly indicating the occurrence of an arcing event. For example, if the average value exceeds a predetermined threshold, an arcing event can be considered detected.

[0132] In some examples, step 1506 may include inputting the first and second output signals (e.g., AFCA and AFCB) from the discriminator as described above into a differential circuit (e.g., differential circuit 1202) to obtain a transition signal. If the amplitude of the transition signal is greater than a predetermined threshold, this means that the phase difference is caused by an arc, leading to the conclusion that an arc has occurred. If the amplitude of the transition signal is less than the predetermined threshold, this means that the phase difference is caused by intentional dissonance, leading to the conclusion that no arc has occurred. The comparison of the amplitude of the transition signal with the predetermined threshold can be performed by the controller of the linear accelerator (e.g., MCU 904, BGC 314).

[0133] Figure 16 This is a flowchart illustrating the processing steps in method 1600 for detecting an electric arc event within a radiotherapy linear accelerator. Method 1600 can be executed automatically by one or more modules of the linear accelerator (e.g., BGC 314, discriminator 312, amplifiers 408, 904, etc.).

[0134] Method 1600 includes steps 1302, 1502, 1504, 1602, 1604, and 1306. Steps 1302, 1502, 1504, and 1306 have been described above.

[0135] Step 1602 includes monitoring the first-order difference of the signal indicating the phase difference. The first-order difference may include the difference between the signal indicating the phase difference at time n and the signal indicating the phase difference at time n-1, i.e., d(n) – d(n-1), as described above regarding… Figure 9 As mentioned above.

[0136] Step 1604 includes detecting an anomaly based on the first-order difference, the anomaly indicating the occurrence of an arcing event. For example, if d(n) – d(n-1) exceeds a predetermined threshold, an arc can be considered detected.

[0137] Figure 17 This is a flowchart illustrating the processing steps in method 1700 for detecting an electric arc event within a radiotherapy linear accelerator. Method 1700 can be executed automatically by one or more modules of the linear accelerator (e.g., BGC 314, discriminator 312, amplifiers 408, 904, etc.).

[0138] Method 1700 includes steps 1302, 1703, 1704, and 1306. Steps 1302 and 1306 have been described above.

[0139] Step 1702 includes monitoring the first-order difference of the reflected RF power signal. The first-order difference may include the difference between the reflected RF power signal at time n and the reflected RF power signal at time n-1, i.e., d(n)–d(n-1).

[0140] Step 1704 includes detecting an anomaly based on a first-order difference, the anomaly indicating the occurrence of an arcing event. For example, if d(n) – d(n-1) exceeds a predetermined threshold, an arc can be considered detected.

[0141] While certain embodiments have been described, these embodiments are presented by way of example only and are not intended to limit the scope of the invention. In fact, the novel methods and apparatus described herein can be embodied in various other forms; furthermore, various omissions, substitutions, and changes can be made to the form of the methods and apparatus described herein.

Claims

1. A method of detecting arcing events in a radiotherapy linear accelerator, characterized by, The method comprises: obtaining a reflected radio frequency power signal; detecting an anomaly based on the reflected radio frequency power signal, the anomaly being indicative of an occurrence of an arcing event; and outputting a signal indicative of an occurrence of an arcing event.

2. The method of claim 1, wherein, The linear accelerator comprises one or more modules and the method is automatically performed by the one or more modules of the linear accelerator.

3. The method according to claim 1 or 2, characterized in that, The anomaly indicative of the occurrence of the arcing event is detected based on an amplitude of the reflected radio frequency power signal.

4. The method of claim 3, wherein, The method further comprises monitoring an average of the amplitude of the reflected radio frequency power signal and wherein the anomaly indicative of the occurrence of the arcing event is detected based on the monitored average.

5. The method according to claim 1 or 2, characterized in that, The method further comprises: obtaining a forward radio frequency power signal; and obtaining a signal indicative of a phase difference between the forward radio frequency power signal and the reflected radio frequency power signal; and wherein the anomaly indicative of the occurrence of the arcing event is detected based on the signal indicative of the phase difference.

6. The method of claim 5, wherein, The method further comprises monitoring an average of the amplitude of the signal indicative of the phase difference and wherein the anomaly indicative of the occurrence of the arcing event is detected based on the monitored average.

7. The method according to claim 1 or 2, characterized in that, The method further comprises: obtaining a forward radio frequency power signal; obtaining a signal indicative of a phase difference between the forward radio frequency power signal and the reflected radio frequency power signal; and monitoring a first order difference of the signal indicative of the phase difference and wherein the anomaly indicative of the occurrence of the arcing event is detected based on the first order difference.

8. The method of claim 7, wherein, The first order difference comprises a difference between a signal indicative of a phase difference at time n and a signal indicative of a phase difference at time n-1.

9. The method according to any one of claims 5 to 8, characterized in that, The method further comprises inputting the reflected radio frequency power signal and the forward radio frequency power signal to a discriminator, the discriminator processing the reflected radio frequency power signal and the forward radio frequency power signal and outputting a first output signal and a second output signal; wherein the signal indicative of the phase difference is obtained by calculating a difference between the second output signal and the first output signal.

10. The method of claim 9, wherein, Detecting the anomaly indicative of the occurrence of the arcing event in the signal indicative of the phase difference comprises: inputting the first output signal and the second output signal to a difference circuit to obtain a jump signal; and determining that an amplitude of the jump signal exceeds a predetermined threshold.

11. The method according to any of the preceding claims, characterized in that, The arcing event comprises an arc being created in a radio frequency power transmission path of the linear accelerator.

12. The method according to any of the preceding claims, characterized in that, Outputting a signal to a user indicative of an occurrence of an arcing event.

13. A computer program comprising instructions, characterized in that, The instructions, when executed by a computer, cause the computer to perform the method of any preceding claim.

14. A computer readable medium comprising instructions, characterized in that, The instructions, when executed by a computer, cause the computer to perform the method of any of claims 1 to 12.

15. A radiotherapy linear accelerator system characterized by, comprise: one or more modules collectively configured to perform the method of any of claims 1 to 12.

16. A radiotherapy linear accelerator system comprising one or more modules collectively configured to: obtain a reflected radio frequency power signal; detect an anomaly based on the reflected radio frequency power signal, the anomaly being indicative of an occurrence of an arcing event; and outputting a signal indicating that an arcing event has occurred.

17. The system of claim 16, wherein, The one or more modules include a reflected radio frequency signal detector configured to obtain the reflected radio frequency power signal.

18. The system of claim 17, wherein, The one or more modules further include a forward radio frequency signal detector configured to obtain a forward radio frequency power signal.

19. The system of claim 18, wherein, The one or more modules further include a discriminator, an amplifier, and a controller; and wherein: The forward radio frequency signal detector and the reflected radio frequency signal detector are configured to send the forward radio frequency power signal and the reflected radio frequency power signal to the discriminator; The discriminator is configured to process the forward radio frequency power signal and the reflected radio frequency power signal and output a first output signal and a second output signal; The amplifier is configured to calculate a difference between the second output signal and the first output signal to obtain a signal indicating a phase difference between the forward radio frequency power signal and the reflected radio frequency power signal and output the signal indicating the phase difference to the controller; The controller is configured to detect an anomaly in the signal indicating the phase difference that indicates the occurrence of the arcing event and output a signal indicating that an arcing event has occurred.

20. The system of claim 19, wherein, The one or more modules further include a difference circuit, and wherein: The difference circuit is configured to receive the first output signal and the second output signal from the discriminator and obtain a jump signal; and The controller is configured to receive the jump signal from the difference circuit and determine that an amplitude of the jump signal exceeds a predetermined threshold.

21. The system of claim 19 or 20, wherein, The controller is a microcontroller unit.

22. The system of any one of claims 19-21, wherein, The controller is a beam generation controller of the linear accelerator.

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