Method for use with a radiation therapy device

Abstract

A method for determining whether a repair or replacement of an electron gun of a radiotherapy apparatus should be scheduled is described. The radiotherapy apparatus includes a linear accelerator and is configured to provide therapeutic radiation to a patient. The radiotherapy apparatus includes: a vacuum tube including an electron gun, a waveguide configured to accelerate electrons emitted by the electron gun toward a target to produce the radiation. The radiotherapy apparatus also includes a current sensor configured to provide a signal indicative of a current supplied to the electron gun. The method includes: receiving a current value; processing the current value; and determining, based on the processing of the current value, whether a repair or replacement of the electron gun should be scheduled. Processing the current value includes: determining whether the current value satisfies at least one threshold criterion; and determining whether the current value has changed by at least a threshold amount within a specific time period.

Description

Technical Field

[0001] The present disclosure relates to the field of predictive maintenance and remote diagnostics, and in particular to methods for determining whether to schedule repair or replacement of an electron gun in a radiotherapy apparatus, determining the nature of a fault in a radiotherapy apparatus, and determining whether maintenance of a radiotherapy apparatus should be scheduled. Background Art

[0002] Radiotherapy units are important tools in modern cancer treatment. Radiotherapy units are large, complex machines with many moving parts and interoperating mechanisms. Despite precise engineering and rigorous testing, some components of a radiotherapy unit may begin to degrade during its lifetime. This can sometimes lead to suboptimal operation and even, occasionally, safety overrides.

[0003] If at any point during treatment, a radiotherapy device begins to function outside of its normal operating parameters, a safety override or "break" occurs whereby the machine stops delivering radiation to ensure patient safety. This situation is inconvenient because it increases treatment time and, in some cases, means that a treatment session must be ended prematurely. Unplanned equipment downtime can disrupt planned treatment schedules and can be costly to the owner due to loss of revenue, maintenance and repair costs, or both.

[0004] It has been speculated that predictive maintenance and / or remote diagnostic techniques could be applied to radiotherapy machines. However, given the complexity of the machines and the sheer amount of data that may be collected during operation, it is difficult to know how to analyze any of the available data to inform predictive maintenance techniques. For example, while a particular data pattern may indicate a particular fault or indicate that a particular component has degraded to the point that it will soon begin to operate outside of its optimal operating parameters, identifying the connection between a particular data pattern and a particular faulty or degraded component is often non-intuitive even for experienced maintenance engineers. Even when a problematic machine is identified, attempting to determine the nature of the fault is very difficult given the richness of the data and the complex interrelationships between the various components of the machine. In other words, even if a large amount of data from a radiotherapy device is available, remotely determining the nature of the fault or assessing the condition of a particular component is not a trivial matter.

[0005] The present disclosure relates in part to identifying when the electron gun of a radiotherapy device is approaching the time when it should be replaced or repaired. To date, there has been no such predictive method, and existing maintenance and repair methods involve noticing that a particular device has experienced multiple safety overrides and dispatching a field service engineer to inspect the machine and diagnose and resolve the problem. Often, the type of problem or faulty component is unknown in advance, so time-consuming diagnostic tests must be performed on-site. As a result, existing methods result in a significant amount of machine downtime. Moreover, in existing methods, the field service engineer is not aware of the potential problem until the component has degraded to the point where the radiotherapy machine is experiencing a safety interruption or even until the point where the radiotherapy machine cannot operate within its safety parameters. This means that maintenance of the radiotherapy machine is often scheduled at times that are inconvenient or inefficient for both the field service engineer resources and the resources of the hospital or other machine owner.

[0006] The present invention seeks to address these and other shortcomings encountered in the prior art by providing a method for preferably remotely determining whether repair or replacement of an electron gun in a radiotherapy apparatus should be scheduled, determining the nature of a fault in the radiotherapy apparatus, and determining whether maintenance of the radiotherapy apparatus should be scheduled. Summary of the invention

[0007] The invention is set out in the independent claim. Optional features are set out in the dependent claims.

[0008] According to one aspect of the present invention, a method for determining whether a repair or replacement of an electron gun of a radiotherapy apparatus should be arranged is provided. The radiotherapy apparatus includes a linear accelerator. The apparatus is configured to provide therapeutic radiation to a patient and includes: a vacuum tube including an electron gun, a waveguide configured to accelerate electrons emitted by the electron gun toward a target to produce the radiation; and a current sensor. The current sensor is configured to provide a signal indicative of a current supplied to the electron gun. The method includes: receiving a current value; processing the current value; and determining, based on the processing of the current value, whether a repair or replacement of the electron gun should be arranged. The processing of the current value includes: determining whether the current value satisfies at least one threshold criterion; and determining whether the current value has changed by at least a threshold amount within a specific time period.

[0009] According to another aspect of the present invention, a method for determining whether maintenance of a radiotherapy device should be scheduled is provided, the radiotherapy device including a linear accelerator and configured to provide therapeutic radiation to a patient, the radiotherapy device including: a vacuum tube including: an electron gun; a waveguide configured to accelerate electrons emitted by the electron gun toward a target to produce the radiation; and a current sensor configured to provide a signal indicative of a current supplied to the electron gun; the method comprising: receiving a current value derived from the signal provided by the current sensor; processing the current value to determine whether the current value satisfies at least a first threshold criterion; determining whether the total amount of time that the electron gun is in a radiation mode satisfies at least a second threshold criterion; and determining whether maintenance of the radiotherapy device should be scheduled if the first threshold criterion and the second threshold criterion are satisfied.

[0010] According to a further aspect of the invention, there is provided a method for determining the nature of a fault in a radiotherapy apparatus, the radiotherapy apparatus comprising a linear accelerator and being configured to provide therapeutic radiation to a patient, the radiotherapy apparatus comprising: a gantry configured to rotate a vacuum tube around the patient so that radiation can be directed around the patient towards the patient from a plurality of angles and / or directions; a vacuum tube comprising: an electron gun; a waveguide configured to accelerate electrons emitted by the electron gun towards a target to produce the radiation; and a voltage sensor configured to provide a signal indicative of a voltage applied to the electron gun, the method comprising: receiving a voltage value derived from a signal provided by the voltage sensor during rotation of the gantry; processing the voltage value, wherein processing the voltage value comprises: determining whether the voltage value satisfies at least one first threshold criterion; and determining, based on the processing of the voltage value, whether the nature of the fault is associated with the electron gun. BRIEF DESCRIPTION OF THE DRAWINGS

[0011] Specific embodiments will now be described, by way of example only, with reference to the accompanying drawings, in which:

[0012] Figure 1 A schematic diagram of a radiotherapy device including a LINAC is depicted;

[0013] Figure 2 A system according to the present disclosure is depicted;

[0014] Figure 3 depicts a graph showing data that may be used in the methods of the present disclosure;

[0015] Figure 4 is a flow chart depicting a method according to the present disclosure;

[0016] Figure 5 is a flow chart depicting a method according to the present disclosure;

[0017] Figure 6depicts a graph showing vacuum or pressure values ​​generated by a sensor according to the present disclosure;

[0018] Figure 7 depicts a region of a vacuum tube according to the present disclosure;

[0019] Figure 8a and Figure 8b is a flow chart depicting a method according to the present disclosure;

[0020] Figure 9a and Figure 9b is a flowchart depicting a method according to the present disclosure; and

[0021] Fig.10 is a flow chart depicting a method according to the present disclosure. DETAILED DESCRIPTION

[0022] The present disclosure relates to a method for determining whether one or more components of a radiotherapy machine or device should be repaired or replaced and / or determining to what extent such components are operating within safety parameters and optimal operating parameters. The radiotherapy device may be adapted to deliver a radiation beam to a patient in order to treat a tumor. An example of a radiation source for generating a therapeutic radiation beam is a linear accelerator (LINAC). A clinical LINAC device is configured to deliver high energy radiation to a patient.

[0023] Radiation therapy machines are beginning to be configured to generate and record large amounts of data as they operate; for example, radiation therapy machines are configured to provide sensor readings from a variety of different sensors. These sensors generate data that can be stored in a database. Radiation therapy devices can also be configured to allow remote connectivity, which enables maintenance engineers to access a wealth of information about any connected machine without having to travel to the location where the machine is located. In many cases, it is expected that the machine can be returned to optimal performance without the engineer having to physically interact with the machine. However, there are still cases where a fault cannot be repaired remotely, and an engineer must be dispatched to: inspect the machine; determine the nature of the fault; and perform any required maintenance. If the repair involves replacing a part, additional machine downtime is required before the machine can be back online.

[0024] Some methods of the present invention relate to evaluating the condition and / or performance of a component of a radiotherapy device during its operation, so as to preferably remotely identify and determine whether the component is approaching the end of its operating life, and therefore determine whether the component should be replaced or repaired. Other methods of the present invention relate to determining the nature of a fault in a radiotherapy device or determining whether maintenance of a radiotherapy device should be scheduled. The present application relates in part to determining whether a filament of a cathode of an electron gun is approaching the end of its operating life. Such techniques are advantageous because they allow a manufacturer or maintenance service provider to keep an eye on the machine and know what will be needed to repair the machine before arriving. Some disclosed techniques allow monitoring the operation of an electron gun, so that an electron gun cathode filament that is approaching the end of its operating life but still operating within the required safety parameters can be identified. This in turn allows, for example, the repair and / or replacement of the electron gun to be scheduled for the next convenient maintenance point. The disclosed methods help reduce machine downtime, thereby minimizing interruptions to the normal operation of the machine. The disclosed techniques can also be used to more effectively plan machine downtime, so as to obtain a more convenient or cost-effective time for the owner and / or patient of the equipment.

[0025] As described above, the present application relates in part to determining the nature of a fault in a radiotherapy apparatus, and in particular, determining whether an electron gun is faulty. For example, some methods of the present invention relate to determining that an electron gun of a radiotherapy apparatus has come loose from its carrier, or more specifically, determining that a cathode of an electrode gun has come loose from its carrier. This may cause the radiotherapy apparatus to operate suboptimally. Such techniques are advantageous because they allow a manufacturer or maintenance service provider to keep an eye on a machine, knowing what will be required to repair the machine prior to arriving. The disclosed techniques can help reduce machine downtime, thereby minimizing interruptions to the normal operation of the machine. The disclosed techniques can also be used to more effectively plan machine downtime so as to obtain a time that is more convenient or more cost-effective for the owner and / or patient of the equipment.

[0026] As described above, the present application relates in part to determining whether maintenance of a radiotherapy apparatus should be scheduled, particularly due to problems with vacuum quality in a vacuum tube of the radiotherapy apparatus. Poor vacuum quality in the vacuum tube may negatively impact the operating life of an electron gun, referred to as gun life. It can be seen that identifying such vacuum quality problems and scheduling maintenance of the radiotherapy apparatus to address the vacuum quality problems may extend the gun life of the electron gun of the radiotherapy apparatus. Typically, vacuum quality problems are introduced during electron gun replacement. For example, vacuum leaks or contamination may be introduced during the process of replacing an electron gun.

[0027] As known to those skilled in the art, the LINAC includes an electron gun that operates to inject electrons into a waveguide in a manner further described below. The electron gun includes a cathode that is suitable for emitting electrons via a thermionic emission process and is configured to emit electrons via a thermionic emission process. The cathode includes a filament that is either made of a suitable emitting material, coated with a suitable emitting material, or otherwise includes a suitable emitting material. Current passes through the cathode filament to heat it, and the emitting material emits electrons into a vacuum tube, which are then accelerated toward a target in the waveguide. Suitable cathode coatings include barium oxide, strontium oxide, and calcium oxide. By way of another example, the filament can be a thoriated tungsten filament, in which a small amount of thorium is added to the tungsten material that includes the filament.

[0028] However, the cathode filaments used in electron guns have only a limited operating life. This is because the emissive layer on the coated cathode slowly degrades over time. As the filament or filament coating degrades, fewer electrons are emitted as the filament is heated. Also, although electron guns are typically located in a vacuum tube in a UHV environment, the cathode filament is still exposed to small amounts of gas molecules. These gas molecules can be absorbed into the cathode's coating, which causes further degradation of the cathode filament material. This results in a reduction in emissivity, which is exacerbated if there are any small leaks in the vacuum tube.

[0029] The electron gun life or "gun life" is the total amount of time that the electron gun can be operated in the radiation mode before the rate of electron emission drops below an acceptable rate, wherein electrons are emitted by the electron gun. The expected gun life is simply the expected amount of time that the electron gun can be operated in the radiation mode before the rate of electron emission drops below an acceptable rate. An example expected gun life is 1000 hours of operation in the radiation mode.

[0030] The radiation mode or active mode is a mode in which the electron gun emits electrons. In contrast, the standby mode or inactive mode is a mode in which the electron gun does not emit electrons.

[0031] High-level overview of LINAC

[0032] Figure 1 A LINAC adapted and configured to deliver a radiation beam to a patient during radiation therapy is depicted. In operation, the LINAC device generates and shapes a radiation beam and directs it to a target region within a patient according to a radiation therapy plan.

[0033] Medical LINAC machines are necessarily complex, with many interoperating components. Figure 1The depicted LINAC apparatus gives a brief overview of the operation of a typical LINAC, which includes a radio frequency wave source, a waveguide, an electron source, a system capable of creating a strong vacuum including one or more vacuum pumps 130, a heavy metal target that produces X-rays when struck by the electron beam, and a complex arrangement of magnets capable of redirecting and focusing the electron beam onto the target. Figure 1 The apparatus depicted in also includes a treatment head that houses various devices configured to, for example, collimate and shape the generated X-ray beam.

[0034] The RF wave source 102, such as a magnetron, generates RF waves. The RF wave source 102 is coupled to the waveguide 104 and is configured to pulse the RF waves into the waveguide 104. The RF waves pass from the RF wave source 102 through the RF input window and enter the RF input connecting pipe or tube. The RF input connecting pipe or tube is connected to the waveguide and can be as shown in FIG. Figure 1 As shown, the waveguide is joined at an angle of substantially 90°. The connecting tube or pipe can join the waveguide via a so-called "elbow joint" or "T-joint". An electron source 106, such as an electron gun, is coupled to the waveguide 104 and is configured to inject electrons into the waveguide 104. In the electron source 106, electrons are thermally emitted from the cathode filament when the filament is heated. The temperature of the filament controls the number of electrons injected. The injection of electrons into the waveguide 104 is synchronized with the pumping of the radio frequency wave into the waveguide 104. The design and operation of the radio frequency wave source 102, the electron source 106 and the waveguide 104 are such that the radio frequency wave accelerates the electrons to very high energies as the electrons propagate through the waveguide 104.

[0035] The design of the waveguide 104 depends on whether the LINAC uses standing waves or traveling waves to accelerate electrons, but the waveguide generally comprises a series of cells or cavities, each connected by a hole or "aperture" through which the electron beam can pass. The cavities are coupled so as to produce an appropriate electric field pattern that accelerates the electrons propagating through the waveguide 104. As the electrons are accelerated in the waveguide 104, the electron beam path is controlled by an appropriate arrangement of steering magnets or steering coils surrounding the waveguide 104. The arrangement of steering magnets may include, for example, two sets of quadrupole magnets.

[0036] Once the electrons are accelerated, they enter the flight tube. The flight tube may be connected to the waveguide tube by a connecting tube. The connecting tube or connecting structure may be referred to as a drift tube. The drift tube also forms a part of the vacuum tube. The RF wave leaves the waveguide tube via an RF output connecting pipe or tube connected to the drift tube. Like the RF input pipe that introduces the RF into the waveguide, the pipe or tube through which the RF leaves the waveguide tube is connected to the vacuum tube via an elbow joint or a "T-shaped" joint. The RF is transmitted from the vacuum system via the RF output window of the sealed vacuum system.

[0037] The flight tube is maintained under vacuum conditions by a pump system. The electrons travel along a cyclotron path towards a heavy metal target. The target may comprise, for example, tungsten. While the electrons travel through the flight tube, an arrangement of focusing magnets is used to direct and focus the beam on the target. The cyclotron path allows the overall length of the LINAC to be reduced while ensuring that an accelerated electron beam consisting of electrons with a small energy spread is focused on the target.

[0038] In order to ensure that the propagation of electrons is not hindered when the electron beam travels toward the target, a vacuum system including a vacuum pump 130 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 a speed close to the speed of light in the evacuated waveguide 104. The electron gun 106, the waveguide 104 and the flight tube together form a vacuum tube, wherein electrons can be accelerated and directed to the target under vacuum conditions. In an implementation including a drift tube connecting the waveguide 104 to the flight tube, the drift tube also forms a part of the vacuum tube. The vacuum tube has two ends. These ends can be described as opposite ends. The electron gun 106 is located at a first end of the vacuum tube, and the flight tube is located at a second end of the vacuum tube. In other words, the flight tube is located at the end of the waveguide 104 away from the electron gun 106, and is therefore located at the end of the vacuum tube away from the electron gun 106.

[0039] The combination of components maintained under vacuum, such as vacuum tubes and any connecting pipes and pipes (such as those coupling the RF input and output windows to the internal volume of the vacuum tubes and pumps), can be referred to as a vacuum system. The vacuum system is sealed and constantly maintained under vacuum. In order to produce the necessary high vacuum conditions, the vacuum system may undergo several stages of pumping before a high quality vacuum can be maintained using, for example, an ion pump. For example, first, an ordinary piston-based pump can be used, followed by a stage in which a turbomolecular pump is used to further reduce the pressure inside the vacuum system. Finally, an ion pump is used to ensure that the system remains at an ultra-low pressure.

[0040] When high energy electrons hit the target, X-rays are generated in all directions. The target is located inside the flight tube and at the end of the flight tube to seal the vacuum system. The flight tube also includes a target window that is transparent to X-rays, which is positioned to allow X-rays generated when the LINAC is operating to pass through the target window and into the treatment head 110 from the evacuated flight tube. At this time, the primary collimator blocks X-rays traveling in certain directions and only allows X-rays traveling forward to pass through to produce a cone beam. The X-rays are filtered and then pass through one or more ion chambers for dose measurement. Before the beam enters the patient as part of the radiation therapy, the beam can be shaped in various ways by a beam shaping device, such as by using a multi-leaf collimator.

[0041] In some implementations, the LINAC is configured to emit either an X-ray beam or an electron particle beam. Such implementations allow the device to provide electron beam therapy, i.e., an external beam therapy that directs electrons rather than X-rays to a target area. By adjusting components of the LINAC, it is possible to "switch" between a first mode that emits X-rays and a second mode that emits electrons. Essentially, the first and second modes can be swapped by moving a heavy metal target in or out of the electron beam path and replacing it with a so-called "electron window." The electron window is substantially transparent to electrons and allows the electrons to leave the flight tube.

[0042] The end of the flight tube can be sealed by a component including a target and an electron window. Then, by moving the flight tube so that the electron beam is directed to either the target or the electron window, it is possible to switch between the first mode and the second mode. Therefore, the drift tube that connects the waveguide to the beginning of the flight tube is slightly flexible to allow the flight tube to move. In other words, when the user changes between using electron and x-ray energies, the flight tube will move, which places either the tungsten target (x-ray) or the electron window (electrons) at the location to be treated.

[0043] The LINAC device also includes several other components and systems. The entire system is cooled by a water cooling system (not shown in the figure). The water cooling system can be used in particular to cool the waveguide 104, the target and the RF source 102. In order to ensure that the LINAC does not leak radiation, appropriate shielding is also provided. As will be understood by those skilled in the art, a LINAC device for radiotherapy will have additional equipment, such as a gantry for supporting and rotating the LINAC, a patient support surface, and a controller or processor configured to control the LINAC device.

[0044] The gantry is configured to rotate the LINAC device around the patient so that radiation can be directed to the patient from multiple angles and / or directions around the patient. The LINAC device may include a sensor or sensing device configured to provide a signal indicative of the extent to which the gantry has been rotated, from which the gantry angle value can be derived.

[0045] Device and sensor details

[0046] Figure 2A cross section of a vacuum tube of a LINAC is depicted. As described above, the vacuum tube consists of an electron gun 202, a waveguide 204, and a flight tube 206. The electron gun 202 is configured to inject electrons into the waveguide 204. In this example, the electron beam can be focused by a first arrangement 210 of focusing magnets and a second arrangement 215 of focusing magnets. The beam is "steered," i.e., directed, by a first arrangement 220 of steering magnets and a second arrangement 225 of steering magnets. While the LINAC is in use, the electron gun 202, the waveguide 204, and the flight tube 206 are maintained under high vacuum conditions by a vacuum system or suitable vacuum equipment.

[0047] The LINAC also includes a current sensor 235, such as an ammeter. The current sensor 235 may be included in the electron gun 202. The current sensor 235 is adapted to detect and is configured to detect the current supplied to the electron gun, i.e., the current passing through the cathode filament. The current sensor 235 is communicatively coupled to the device controller 240, and data related to the electron gun current is transmitted to the device controller. The current supplied to the electron gun is measured by the current sensor and transmitted to the device controller 240 at a specific frequency, for example, the current sensor 235 may provide current measurements to the device controller 240 every second.

[0048] The LINAC also includes a voltage sensor 237, such as a voltmeter. The voltage sensor 237 may be included within the electron gun 202. The voltage sensor 237 is adapted to detect and is configured to detect a voltage applied to the electron gun, such as a voltage across a cathode filament. The voltage sensor 237 is communicatively coupled to the device controller 240, and data related to the electron gun voltage is transmitted to the device controller. The voltage supplied to the electron gun is measured by the voltage sensor 237 and transmitted to the device controller 240 at a particular frequency, for example, the voltage sensor 237 may provide a current measurement to the device controller 240 every second.

[0049] The LINAC also includes a gantry (not depicted) configured to rotate the LINAC apparatus about the patient so that radiation can be directed toward the patient from multiple angles and / or directions about the patient. The LINAC apparatus also includes a gantry rotation sensor or sensing device configured to provide a signal indicative of the extent to which the gantry has been rotated, from which the gantry angle value can be derived.

[0050] exist Figure 2In an example of , the vacuum system includes two pumps coupled to either end of a vacuum tube. The region of the vacuum tube to which the first pump 230 is coupled is disposed at an end of the vacuum tube opposite to the region of the vacuum tube to which the second pump 234 is coupled. The first pump 230 is coupled to a first end of the vacuum tube where the electron gun 202 is located. The first pump 230 may be coupled to a region of the vacuum tube adjacent to the electron gun (i.e., a region adjacent to where the electron gun 202 injects electrons into the waveguide 204). The first pump 230 is arranged and configured to remove gas molecules from the vacuum tube, and in particular is arranged and configured to remove gas molecules primarily from a first region of the vacuum tube. The first region may include the volume of the tube occupied by the electron gun and / or a region of the vacuum tube near the electron gun. The region of the vacuum tube near the electron gun may be described as being adjacent to or near the electron gun. The second pump 234 is coupled to a second region of the vacuum tube, which is located at a second end of the vacuum tube where the flight tube 206 and, therefore, the target is located. The second pump 234 may be coupled to the flight tube 206 itself. The second pump 234 is arranged and configured to remove gas molecules from the vacuum tube, and is particularly arranged and configured to remove gas molecules primarily from a second region of the vacuum tube. The second region may include the flight tube 206 itself and / or a region of the vacuum tube close to the flight tube 206. The region of the vacuum tube close to the flight tube may be described as being adjacent to or near the flight tube. For example, the second pump 234 may be coupled to the vacuum tube in a connection region between the waveguide 204 and the flight tube 206.

[0051] In an implementation, the gun pump is connected to a tube or pipe that joins the RF wave source to the waveguide. The connecting tube or pipe introduces RF into the waveguide and joins the waveguide via an elbow joint at the area of ​​the vacuum tube. In other words, the RF input connecting pipe or tube joins the RF input window to the waveguide. Typically, the RF input connecting pipe or tube joins the waveguide at the area of ​​the waveguide adjacent to the electron gun or is coupled to it.

[0052] In an implementation, the target pump is connected to a tube or conduit through which the RF leaves the waveguide. The connecting tube or conduit connects a region of the waveguide with the RF output window. The RF output connecting conduit joins or connects to the waveguide at a region of the waveguide adjacent to the flight tube (e.g., drift tube). The RF input tube / conduit and the RF output tube / tube are connected to the vacuum tube via an elbow joint or "T-shaped" joint. This implementation is Figure 7 Depicted in Figure 7A drift tube 707 is depicted positioned between a waveguide (only a small portion of which can be seen in the figure) and a flight tube 706 (only a small portion of which can be seen in the figure). An "elbow joint" 705 connects the drift tube 707 to an RF output connection conduit 709, which terminates in an RF output window through which the RF can exit the vacuum system. The target pump is connected to the region of the RF outlet connection conduit between the elbow joint 705 and the RF outlet window (not shown). Thus, the region of the vacuum tube to which the second pump is coupled can be described as being adjacent to or proximate to the flight tube and / or proximate to or adjacent to the drift tube coupled to the flight tube.

[0053] The first pump 230 may be described as being positioned near or substantially near the electron gun 202, and therefore substantially near where the electrons enter the waveguide 204. The second pump 234 may be positioned near or substantially near the entrance of the flight tube 206 where the target is located. Thus, the first pump 230 may be referred to as a "gun pump" and the second pump 234 may be referred to as a "target pump."

[0054] The first pump and the second pump are used to generate high vacuum conditions inside the electron gun 204, the waveguide 206 and the flight tube 206, and can therefore be described as vacuum pumps. Suitable vacuum pumps include ion pumps, such as diode and noble diode pumps. Ion pumps are capable of generating very low pressures inside the sealed volume of the vacuum tube. Other pumps capable of providing UHV conditions may also be used, including turbomolecular pumps and diffusion pumps.

[0055] No sensors are located inside the vacuum tubes (i.e., waveguides and flight tubes) themselves, because there is very little space inside these components to fit such sensors. Moreover, any components placed inside the waveguide will affect the electromagnetic field inside the waveguide, which may have a negative impact on the acceleration of the electrons inside the waveguide. Further, components placed inside the vacuum tubes at the area where the electrons pass through are subject to a lot of induced radiation, which would be undesirable. Finally, if any sensor placed inside the vacuum tube fails, it will be very difficult to replace it.

[0056] However, an indication of the pressure inside the vacuum tube can be obtained from a reading provided by the vacuum pump itself. The reading from the pump can be used to give an indication of the quality of the vacuum inside the vacuum tube. The first pump 230 includes a first sensor 232 that is adapted to provide and configured to provide a signal indicative of the pressure inside the vacuum tube. Since the first vacuum pump 230 is coupled to a portion of the vacuum tube that is substantially proximate to the electron gun 202, the first sensor 232 is able to provide a signal indicative of the pressure inside the vacuum tube proximate to the electron gun 232. Therefore, the first sensor 232 signal can be referred to as a "gun vacuum" signal or a gun vacuum value.

[0057] Thus, in broad terms, the first sensor is configured to provide a signal indicative of pressure at a first region inside the vacuum tube, and the second sensor is configured to provide a signal indicative of pressure at a second region inside the vacuum tube. The first region and the second region are located at opposite ends of the vacuum tube. In other words, the first region is closer to the first end of the vacuum tube than the second region, and it follows that the second region is closer to the second end of the vacuum tube than the first region.

[0058] In a similar manner to the first pump 230 and the first sensor 232, the second vacuum pump 234 includes a second sensor 236 adapted to provide and configured to provide a signal indicating the pressure inside the vacuum tube. More specifically, the second sensor 206 is configured to provide a signal indicating the pressure inside the vacuum tube close to the target and / or flight tube 206. Therefore, the signal from the second sensor 236 can be referred to as a "target vacuum" signal or a target vacuum value. More generally, the signals provided by the vacuum pumps via their respective sensors can be referred to as pressure signals. The sensors measure the pressure, i.e., the vacuum level, of the corresponding regions inside the first pump and the second pump. These regions are part of the same closed volume defined by the vacuum tube, and therefore, the first sensor is capable of providing a signal indicating the pressure at the first end of the vacuum tube to which the first pump is coupled, and the second sensor is capable of providing a signal indicating the pressure at the second end of the vacuum tube to which the second pump is coupled.

[0059] More generally, the first sensor 232 and the second sensor 236 are configured to provide signals from which a pressure value can be derived that is indicative of the pressure inside the vacuum tube. The pressure value can be based on signals from either or both of the first sensor 232 and the second sensor 236.

[0060] The sensor may include any number of possible sensors suitable for measuring vacuum pressure. Example sensors that may form part of a vacuum pump and may be used to provide a signal indicative of pressure include a Pirani gauge and an ionization gauge. The vacuum pressure at the gun and target end is measured at the Ion Pump Control Unit (IPCU).

[0061] The current sensor 235 and the first and second pumps 230, 234 also include means for communicating with the device controller 240. For example, the current sensor and the pump may include suitable processing circuits and a transmitting antenna. The current sensor and the pump are electronically and / or communicatively coupled to the device controller 240. The device controller 240 receives signals from the current sensor and the pump as the current sensor generates or produces the signal. The device controller 240 is electronically and / or communicatively coupled to the device controller memory 245. The device controller 240 and the device controller memory 245 may be configured to store the signals generated by the current sensor and the pump. The signals generated from the current sensor and the pump include sensor data.

[0062] The device controller 240 is communicatively coupled to the central controller 270, for example, via the network 250. The device controller 240 is configured to transmit (i.e., send) sensor data to the central controller 270 for storage on the central controller memory 275. The central controller memory 275 may include multiple different servers as part of a cloud storage solution. The central controller may be communicatively coupled to multiple radiotherapy devices via the network 250, each of which is configured to transmit signals to the central controller 270 for storage on the central memory 275. The central controller 270 is adapted and configured to process the received signals and store them in a database. Processing the signals may include, for example, calculating and storing daily averages of specific sensor data.

[0063] The radiotherapy device has various sensors, and the signals / readings from the sensors are transmitted to the device controller 240. The signals may be stored in the device controller memory 245 and / or may be transmitted to the central controller 270 via the network. The data may be uploaded to the central controller 270 as it is generated, or may be stored on the device controller memory 245 to be uploaded, for example, periodically as a batch upload. Alternatively, the data may be collected continuously by the device controller 240, for example, the sensor signals may be sampled every 4 seconds (optionally when the device is not delivering radiation), and if the data shows a specific difference from a previously uploaded data point, the data is uploaded. In a specific implementation, data points are uploaded when there is a change of + / - 0.04, and the device controller optionally looks for new data items once every 4 seconds when the device is not delivering radiation, and once every second when the LINAC is delivering radiation.

[0064] The data is stored in a database on the central memory 275 and may include data from sensors, for example, data including current values ​​as represented by signals from the current sensor 235 and pressure values ​​as represented by signals from the first sensor 232 and / or the second sensor 236, the amount of time the electron gun has spent in the radiation mode, the degree of rotation of the gantry as represented by signals from the gantry rotation sensor or sensing device, whether radiation is delivered at a particular time and the dose rate and machine output as indicated by a dosimeter or monitoring chamber, and water temperature at various points around the water cooling system. These types of data are given to provide examples, and those skilled in the art will appreciate that a modern LINAC device may be configured to generate a large amount of data from a large number of sensors.

[0065] The data stored in the database on the central memory 275 may also include a record of the total amount of time the electron gun is in the radiation mode. For a particular electron gun, the received data relating to the amount of time the electron gun spends in the radiation mode may be compiled to provide a record of the total amount of time the electron gun is in the radiation mode.

[0066] The device controller 240 and the central controller 270 are also both communicatively coupled to the remote controller 240. The remote controller 260 can access the central database through the database 250 and using a suitable software platform, which stores information and data about multiple radiation therapy devices. The remote controller 260 can also access the device controller 240 to obtain real-time information about a specific radiation therapy machine.

[0067] Device controller, central controller and remote controller can be described as processor, computer or computing device respectively.Controller can be connected to each other (for example, networking) and / or connected to other machines in local area network (Local Area Network, LAN), intranet, extranet or Internet.Controller can be operated with the ability of server or client machine in client-server network environment respectively, or operated as peer machine in peer (or distributed) network environment.Controller can be each personal computer (Personal Computer, PC), tablet computer, set-top box (Set-TopBox, STB), personal digital assistant (Personal Digital Assistant, PDA), cellular phone, network appliance, server, network router, switch or bridge, or any machine capable of executing a set of instructions (sequential or otherwise), which specifies the action to be taken by the machine.Further, corresponding controller is illustrated, and term "controller" should also be taken as including any set of machines (for example, computers) that execute one or more of the methods discussed herein individually or jointly to execute a set (or multiple sets) of instructions.

[0068] The method of the present disclosure can be implemented on one or more of the device controller memory and the remote controller memory or on any other computer-readable medium. The medium can be a non-transient computer-readable medium. The computer-readable medium carries computer-readable instructions, which are arranged to be executed on the processor so that the controller / processor performs any or all methods described herein. The term "computer-readable medium" as used herein refers to any medium storing data and / or instructions for causing the processor to operate in a specific manner. Such storage media may include non-volatile media and / or volatile media. Non-volatile media may include, for example, optical disks or magnetic disks. Volatile media may include dynamic memory. Exemplary forms of storage media include floppy disks, floppy disks, hard disks, solid-state drives, tapes or any other magnetic data storage media, CD-ROMs, any other optical data storage media, any physical media with a pattern of one or more holes, RAM, PROM, EPROM, flash EPROM, NVRAM, and any other storage chip or cartridge.

[0069] In a LINAC device, it is generally desirable to achieve the highest possible dose rate for a particular therapeutic radiation energy. The most important factor in determining the therapeutic radiation energy is the degree to which electrons can be accelerated by the waveguide, which depends on the RF energy input into the waveguide. The dose rate for a particular radiation energy depends on the number of x-rays emitted from the heavy metal target, which in turn depends on the number of electrons that hit the target. In general, increasing the current supplied to the electron gun increases the number of electrons emitted from the cathode of the electron gun. Therefore, increasing the electron gun current increases the number of electrons entering the waveguide. However, for a given radiation energy, it is not the case that a continuous increase in the electron gun current leads to a continuous increase in the dose rate. This is due to the characteristics of the waveguide and the RF energy that accelerates the electrons through the waveguide. In fact, for a given radiation energy, that is, for a given energy of x-rays including radiation, there is an optimal electron gun current that leads to the highest possible dose rate for the radiation energy. Therefore, the gun current is set so that the LINAC will produce the highest dose rate achievable for that energy.

[0070] Each LINAC device is configured to produce radiation at one of several possible energies. Each of these energies has an associated optimal gun current value. The optimal gun current value for the lowest configured energy may be referred to herein as the XLOW gun current. By way of example, a brand new LINAC machine may have the lowest possible energy of 6MV, with a corresponding XLOW gun current of 7.95A. By way of alternative example, a LINAC device with a lowest configured energy of 4MV may have an XLOW gun current of 7.85A. The various possible radiation energies and their corresponding calibrated optimal electron gun currents are stored in the device controller memory 245, so that when it is desired to change the radiation energy, such as during a treatment process, or between treatments of different patients, the current applied to the electron gun 202 may be adjusted accordingly to ensure that the highest possible dose rate is achieved. In the example, each energy has its own calibration block, so that once the current has been optimized, the current is saved and can be loaded again when changing between energies.

[0071] Engineers find the optimum gun current peak at a particular energy, for example by making 0.01 A adjustments to the gun current before saving the gun current value that results in the highest dose as determined, for example, by the radiotherapy device dosimeter. The electron gun current can be calibrated regularly (e.g., monthly) for each device energy in this way.

[0072] The dose rate or beam energy of a LINAC machine is monitored, for example, by using a signal from an ionization chamber in the treatment head of the LINAC. In an example, the energy and dose rate of the beam can be monitored by monitoring the so-called hump error value. The hump is a measure of the difference in beam shape between the center of the beam and the edge of the beam, and is an indication of the energy of the radiation beam. The hump value can be calculated by comparing the signal from the center region of the ionization chamber with the signal from the outer region of the ionization chamber according to known methods.

[0073] A so-called "interlock value" may be applied to the measured dose rate and / or beam energy. If the difference between the measured dose rate or beam energy and the expected dose rate or beam energy is greater than the interlock value, the LINAC machine undergoes a safety override and will cease operation to ensure patient safety. The machine may then not be started again until the problem is fixed or until an authorized person clears the safety override and authorizes continued use of the machine. In the example, the hump value has an interlock value of 5.0%; that is, if the difference between the measured hump value and the expected hump value is greater than 5.0%, the LINAC machine performs a safety override. Any hump error value other than 0.0 indicates that the beam energy has changed slightly from the previous optimal setting, and the most likely reason for this is that the gun current is "off-peak", i.e., the current supplied to the cathode of the electron gun is not optimal. The optimal gun current may change slightly on the order of days or weeks.

[0074] Thus, while the optimum gun current is periodically calibrated by a field service engineer and saved in the device controller memory 245 for use with the associated LINAC energy until the next calibration, the actual current supplied to the electron gun 202 is regulated by a servomechanism or other feedback system. The servomechanism uses the optimum gun current setting as stored in the device controller memory 245 as the base current, but then uses feedback related to the dose rate obtained from the dosimetry system, such as the hump error, to make minor adjustments to the electron gun current while the radiation device is operating.

[0075] In some implementations, for example, the servo will automatically adjust the gun current to reduce the gun differential to 0. The gun differential is based on the hump error, ie, the difference between the hump outer value and the hump inner value. The servo is adjusted by the dose level data item set by the field service engineer.

[0076] The current sensor may include any number of possible sensors suitable for measuring the current through the cathode filament and the voltage across the cathode filament. The cathode filament current and voltage are measured by appropriate sensors and circuits that form part of the electron gun. It should be understood that the current sensor is a sensor configured to provide a signal or value that indicates the current supplied to the cathode filament. Therefore, the current sensor may include a sensor that measures the resistance of the filament and / or the voltage across the filament, and a suitable processor and memory that uses a lookup table or other calibration data to provide a current value based on the signal or value provided by the current sensor.

[0077] It has been observed that the optimum gun current for a particular LINAC energy decreases over time as the cathode filament ages and degrades. This includes the optimum XLOW current. This is probably because, as the cathode filament in the electron gun degrades during its lifetime, less current is required to achieve a certain electron output. In other words, as the cathode degrades, the filament becomes "weaker" and therefore the resistance of the filament decreases. Therefore, the current required across the filament for the maximum dose rate at a particular LINAC energy decreases. This can be seen in Figure 3 can be seen in the graph.

[0078] Figure 3 The use of sensors such as those on a radiotherapy device (e.g. Figure 2 The graph is generated based on data from a database of sensor values ​​provided by a current sensor (e.g., a current sensor depicted in FIG. 1 ). The graph shows time along the x-axis, current in amperes along the left y-axis, and pressure in arbitrary units along the right y-axis.

[0079] This graph demonstrates the types of signals that may be received from the device controller and accessed by the remote controller. In particular, the graph shows an overall decrease in average XLOW gun current over time. The current value is a daily average of the actual XLOW current supplied to the electron gun. The actual current supplied to the electron gun is determined by the optimal gun current value stored in the device controller memory 245 and the servomechanism / feedback system. The daily average is calculated based on a signal provided by a current sensor, which is either part of the electron gun as described above, or alternatively part of the servomechanism.

[0080] The daily current average is based on the average value of the gun current for XLOW. The gun current will fluctuate as the radiotherapy device delivers radiation. As the radiation is delivered, the electron gun servo monitors, for example, changes in resistance in the filament. However, it cannot track this exactly, so as the gun deviates from its optimal value, the dose will begin to decrease. For example, in some implementations, due to the built-in safety threshold, the servo cannot deviate from the calibrated optimal value by too much. Once the dose rate has moved away from the low dose interlock (calibrated maximum dose rate) to a certain extent or amount, for example, when the dose rate is 80% of the calibrated optimal dose rate, the radiotherapy device will experience a safety interruption, that is, the treatment will be terminated and a notification or alarm will be issued, which indicates that the delivered dose rate has dropped to far below the maximum value and the treatment is stopped to ensure patient safety. As the gun current drifts further beyond the peak value, that is, away from the optimal value, the frequency of these interruptions and alarms will increase. In existing methods, the presence or increased frequency of these interruptions and alarms is relied on to warn field engineers that the electron gun should be arranged for repair or replacement.

[0081] The units of the right y-axis are semi-arbitrary units derived from the vacuum pressure reading from the pump sensor. For a particular ion pump, the voltage across the ion pump is related to the log10 of the current drawn by the pump as follows:

[0082] V rec-out =1.35·log10 I out +6.77

[0083] In an implementation, the vacuum pressure recorded on the ion pump control unit (IPCU) is then converted to give a value between -4.49 and -6.8, where -4.49 relates to a vacuum pressure of 1.55E-04 mBar and -6.8 is 5.60E-08 mBar. Thus, a reading of -5.50 is 4.64E-06 mBar.

[0084] Figure 6 shows the use of data from sensors such as Figure 2232, 236) provided by the sensors 232, 236 depicted in FIG. The graph shows time along the x-axis and pressure along the y-axis. The units of the y-axis are semi-arbitrary units derived from the vacuum pressure readings from the various pump sensors. For a particular ion pump, the voltage of the ion pump is related to the log10 of the current drawn by the pump as follows:

[0085] V rec-out =1.35·log10 I out +6.77

[0086] In an implementation, the vacuum pressure recorded on the ion pump control unit (IPCU) is then converted to give a value between -4.49 and -6.8, where -4.49 relates to a vacuum pressure of 1.55E-04 mBar and -6.8 is 5.60E-08 mBar. Thus, a reading of -5.50 is 4.64E-06 mBar.

[0087] The graph shows the signal received from the target vacuum pump as generated by the target vacuum sensor. The graph demonstrates the type of signal that can be received from the device controller and accessed by the remote controller. A similar graph can be generated for the gun pump. The top line, usually on the graph, is the target pump daily maximum reading. Each data point is the maximum value for a particular day, that is, the maximum value of a particular data between the time period from 00:00 to 23:59. The bottom line, usually on the graph, is the target pump daily minimum reading, where each data point is the minimum value for that day. Finally, the line, usually between the maximum line and the minimum line, is the daily average line. Each data point on this line is the average target pump value for a particular day.

[0088] Specific methods

[0089] Reference now Figure 4 The method depicted in the flowchart of . At step 410, a current value is received. The current value is derived from a signal from a current sensor. As described above, there is an optimal gun current value for a particular radiation energy, however, when the radiation beam is applied, and because the current supplied to the electron gun is controlled by a servo mechanism, the actual current supplied to the electron gun may vary slightly around the optimal value. Therefore, the current measured by the current sensor 235 and received by the device controller 240 varies as the LINAC operates. The current value received at step 410 may be an average of a signal or value received from the current sensor over a period of time. In other words, the current value may be an average current supplied to the electron gun over the period of time. Preferably, the period of time is one day, so that the current value is a daily average of the current supplied to the electron gun. The method may also include: deriving the current value by calculating or otherwise determining the average value of the signal received from the current sensor 235 over the period of time.

[0090] At step 420, the current value is processed. Figure 5 Processing of the current value is described in more detail, but in a preferred embodiment, the processing of the current value includes determining whether the current value satisfies at least one threshold criterion and determining whether the current value has changed by a threshold amount or more over a particular time period.

[0091] At step 430, based on the processing of the current value, it is determined whether repair or replacement of the electron gun should be scheduled. In an example, if the determination at step 420 above is affirmative, that is, if the current value satisfies at least one threshold criterion and the current value has changed by at least a threshold amount within a certain period of time, it is determined that repair or replacement should be scheduled.

[0092] By way of a specific example of steps 410, 420, and 430, signals related to the current supplied to the cathode filament are received from the current sensor 235 at the device controller 240, and these signals are transmitted to the central controller 270 for storage in the central memory 275. The central controller 270 receives the daily average value of the current by calculating or determining the daily average value based on the received current value. The daily average value of the current is then processed; in particular, it is determined whether the average current (e.g., XLOW gun current) for a particular radiation energy is less than 6.90A. As part of the processing of the average current value, it is also determined whether the average XLOW gun current has decreased by 0.05A or more in the past 30 days. Based on the processing of the average current value, it is determined whether repair or replacement of the electron gun should be scheduled. For example, if the above determination is affirmative, it is determined that the electron gun should be repaired or replaced.

[0093] At step 440, the determination of whether a repair or replacement should be scheduled at step 430 is output. This step is optional. Outputting the determination may include: displaying an indication of the determination on a display screen. In response to the indication, a repair or replacement of the electron gun may be scheduled at the next available maintenance point or at a time convenient for the machine owner (e.g., during a planned machine downtime). Outputting the determination may also include: issuing an alert or notification to a field maintenance engineer detailing the determination. The alert may include information about how to test for a malfunction of the electron gun, and may also include information detailing how to replace the electron gun or how to repair the electron gun, such as by replacing a cathode filament. Outputting the determination may also include: issuing a communication, an alert, or otherwise contacting the owner of the radiotherapy device to notify them of the problem and arrange for a repair or replacement.

[0094] In the example, once the conditions described herein have been met and Figure 5Based on the prediction criteria set out in the flowchart, a report is generated and an alert is issued. This alert is then sent to the relevant maintenance team, and they will usually plan the replacement within the next 3-6 weeks, or align with a planned maintenance activity.

[0095] In a preferred embodiment, the device controller 240 receives signals from the current sensors and transmits them to the remote controller 260. The central controller 270 receives the signals and then derives the current value, for example, by calculating an average current value from the signals over a period of time. The average current value is stored on the central controller memory 270. The current value is then processed when the remote controller 260 accesses the central memory 275 via the network 250. However, Figure 4 At least some of the steps shown in , and in some examples all of the steps, may be performed on the device controller 240. It should be understood that any combination of the device controller 240, the central controller 270, and the remote controller 260 may be used to perform the disclosed methods.

[0096] Reference now Figure 5 . The flowchart shows steps 420, 430 and optional step 440 in more detail, and in particular shows the processing of the current value in more detail. At step 510, it is determined whether the received or derived current value meets the first threshold criterion. In a specific example, checking whether the first criterion is met includes: determining that the current value (e.g., the average XLOW gun current value for a particular day) is below a first threshold, such as a first threshold average current value. If so, the criterion is met. In a specific example, it is determined whether the average XLOW gun current is below 6.90A.

[0097] If the current value meets the first threshold criterion, then the process proceeds to step 520. At step 520, it is determined whether the current value has changed by at least a first threshold amount within a specific time period. The first threshold amount may be described as a first specific amount. In a specific example, the first threshold amount is 0.05A, and the specific time period is 30 days, such that it is determined whether the average XLOW gun current has decreased by 0.05A or more over the last 30 days. If so, the criterion is met.

[0098] If the current value changes by a threshold amount within the time period, then a determination is made at step 530 that the electron gun should be scheduled for repair or replacement. This determination may be output at step 540 in a manner similar to the output at step 440.

[0099] If it is determined at step 520 or step 560 that the current value has not appropriately changed by the first or second threshold amount within the particular time period, then the replacement / repair criteria are not met and it is determined at step 570 that the electron gun should not be repaired or replaced.

[0100] If it is determined at step 510 that the current value does not meet the first threshold criterion, e.g., the daily average value of the XLOW electron gun current is not less than 6.90A, then at step 550, it is determined whether the current value meets the second threshold criterion. In an example, checking or determining whether the second threshold criterion is met may include determining whether the current value is below a second threshold, such as a second average current value. In a specific example, checking to meet the second threshold criterion includes determining that the current value (e.g., the average XLOW gun current value for a particular day) is below the second threshold. In a specific example, it is determined whether the average XLOW gun current is below 7.20A.

[0101] Step 550 may alternatively or additionally include determining that the current value is within a threshold range, wherein the threshold range is defined by an upper range value and a lower range value. The lower range value may be equal to the first threshold. For example, at step 550 it may be determined whether the average XLOW gun current for a particular day is between 6.90 amps and 7.20 amps.

[0102] If the current value meets the second threshold criteria, then the process proceeds to step 560. At step 560, it is determined whether the current value has changed by at least a second threshold amount within a specific time period. The second threshold amount may be described as a second specific amount. In a specific example, the second threshold amount is 0.10A, and the specific time period is 30 days, such that it is determined whether the average XLOW gun current has decreased by 0.10A or more in the last 30 days.

[0103] If the current value changes by a second threshold amount within the time period, then a determination is made at step 530 that the electron gun should be scheduled for repair or replacement. The determination may be output at step 540 in a manner similar to the output at step 440.

[0104] The present inventors have noted that as the electron gun in a LINAC reaches the end of its useful life, the rate of change of the optimum current increases. In other words, the current that must be supplied to the cathode filament for a particular LINAC energy in order to try to obtain the optimum dose rate decreases more rapidly as the electron gun reaches the end of its useful life. The use of a threshold value related to whether the current value has changed by a particular amount over a period of time (i.e. a threshold value related to the rate of change of the current value) allows calibration errors to be taken into account and ensures that only devices that are accelerating failures are flagged for repair or replacement. It has been noted that devices operating at very low gun currents are still able to operate within acceptable operating parameters, for example being able to provide an acceptable dose rate. The use of a threshold value related to the rate of change of the gun current helps to ensure that unnecessary maintenance visits and / or repairs and replacements are not caused.

[0105] In some implementations, the first threshold at step 510 is a lower threshold than the second threshold at step 550. In conjunction with this, the first threshold amount at step 520 is less than the second threshold amount at step 560. These factors together mean that an electron gun having a lower current value, which itself indicates that the filament has degraded to a greater degree, needs to meet a lower current "rate" criterion in order to be classified as an electron gun that should be repaired or determined.

[0106] In a specific example, determining whether the first criterion is met includes checking that the XLOW electron gun current is less than 6.90 A, and determining whether the second criterion is met includes checking that the XLOW electron gun current is less than 7.2 A. Figure 3 The graph, as of 1 August 2017, for a specific radiotherapy apparatus comprising a LINAC and an electron gun, follows Figure 4 and Figure 5 Referring to the graph, the current value on August 1, 2017 was about 7.31 A. Therefore, in steps 510, 550, neither the first or second threshold criteria are met, and in step 570, it is determined that the electron gun does not need to be scheduled for repair or replacement.

[0107] The same process is followed on November 1, 2017, on which date the current value is 7.19 A. In this scenario, 7.19 A is greater than 6.90 A, so the first threshold criterion at step 510 is not met. However, the current value is below 7.2 A, so the second threshold criterion is met at step 550. However, when reviewing the current values ​​for the previous 30 days (which is the relevant particular time period in this example), it is determined that the current value has not changed by the second threshold amount of 0.10 A. Therefore, it is determined at step 570 that the electron gun does not need to be replaced.

[0108] The same process is followed on August 1, 2018. The gun current value is 6.87A, so at step 510, the gun current value does not meet the first threshold criterion. In reviewing the previous 30 days of data, it is determined at step 520 that the value has changed by at least the first threshold amount of 0.05A, so the electron gun should be scheduled for repair or replacement. Following this determination, an alarm is issued and / or a message is sent to the relevant repair team requesting that they schedule a field visit to the radiotherapy device that includes the electron gun. The team is able to determine whether the electron gun needs to be either repaired or replaced.

[0109] The method disclosed herein may be performed periodically, for example daily, to continuously monitor whether the electron gun of a radiotherapy apparatus should be repaired or replaced, or at least schedule repair or replacement.

[0110] It should be understood that although Figure 5 A specific order of steps is set forth in the , but the steps can be performed in a different order.

[0111] It should be understood that although reference is made to the XLOW current, i.e., the current supplied to the cathode for the lowest configuration energy of the LINAC, the current at which the LINAC is operated at any particular energy may be used. For machines manufactured by the applicant, XLOW is typically 6Mv in 85% of the machines, and 6MV is used more than any other energy. In fact, about 85% of all clinical applications use 6MV. Therefore, the advantage of using the current at the XLOW energy is that this is the energy used most by LINAC machines, and therefore, monitoring the current at this energy will produce the most data items for analysis.

[0112] Reference now Figure 8a and Figure 8b The method is depicted in a flow chart of the invention. The method identifies whether an electron gun of a radiotherapy device has poor gun life due to vacuum problems by analyzing various parameters.

[0113] At step 810, a current value is received in a manner similar to step 410 described above. The current value is derived from a signal from a current sensor. As described above, there is an optimal gun current value for a particular radiation energy, however, when the radiation beam is applied, and because the current supplied to the electron gun is controlled by a servo mechanism, the actual current supplied to the electron gun may vary slightly around the optimal value. Therefore, the current measured by the current sensor 235 and received by the device controller 240 varies as the LINAC operates. The current value received at step 810 may be an average of a signal or value received from the current sensor over a period of time. In other words, the current value may be an average current supplied to the electron gun over the period of time. Preferably, the period of time is one day, so that the current value is a daily average of the current supplied to the electron gun. The method may also include: deriving the current value by calculating or otherwise determining the average of the signal received from the current sensor 235 over the period of time.

[0114] At step 820, the current value is processed. In a preferred embodiment, the processing of the current value includes determining whether the current value meets at least one first threshold criterion. Optionally, this includes determining that the current value has dropped below a threshold current value, such as below 7.35A.

[0115] Exceeding this first threshold criterion can give a warning that the electron gun is potentially at about 60% of its lifetime. This threshold criterion can also give a warning of about three months before a potential failure of the electron gun, which allows repair activities to be aligned with planned maintenance activities and also allows time to prepare required additional parts or equipment such as ion pumps.

[0116] By way of a specific example of steps 810 and 820, signals related to the current supplied to the cathode filament are received from the current sensor 235 at the device controller 240 and transmitted to the central controller 270 for storage in the central memory 275. The central controller 270 receives the daily average value of the current by calculating or determining the daily average value based on the received current value. The daily average value of the current is then processed; in particular, it is determined whether the average current for a particular radiant energy (e.g., XLOW gun current) is less than 7.35A.

[0117] At step 830, a determination is made as to whether the total amount of time that the electron gun is in the radiation mode satisfies at least a second threshold criterion. The determination may be made by accessing data in a database stored on the central memory 275, the data including a record of the total amount of time that the electron gun is in the radiation mode. Alternatively, when data relating to the total amount of time that the electron gun is in the radiation mode is stored at either or both of the device controller memory or the remote controller memory, at least one of these locations may be accessed to obtain the data. In a preferred embodiment, the determination is made as to whether the total amount of time that the electron gun is in the radiation mode is less than a threshold time period, optionally wherein the time period is 600 hours.

[0118] Meeting the second threshold criterion may indicate that the gun life of the electron gun is shorter than expected, especially when considered in conjunction with the first threshold criterion. If both the first and second criteria are met, this indicates that the electron gun is degrading earlier than expected. This may indicate a vacuum problem with the vacuum tube.

[0119] At optional step 840, a pressure value is received. The pressure value is based on a signal received from at least one of the first and second sensors 232, 236 associated with the first and second pumps 230, 234. As described in detail elsewhere herein, the first and second sensors are configured to provide a signal indicating the pressure inside the vacuum tube. More specifically, the first sensor is configured to provide a signal indicating the pressure inside the vacuum tube near the electron gun, and the second sensor is configured to provide a signal indicating the pressure inside the vacuum tube near the flight tube and / or the target. The first signal is processable to provide a first value indicating the pressure at the first end of the vacuum tube, and the second signal is processable to provide a second value indicating the pressure at the second end of the vacuum tube. The first value is derived from the signal from the first sensor in any manner disclosed herein. Similarly, the second value is derived from the signal from the second sensor in any manner disclosed herein.

[0120] The signal is received at one or more of the device controller and the remote controller.For example, the signal may be received at the device controller and stored in the device controller memory as part of a database / log of signals received from that particular radiation therapy machine.

[0121] Signals may also be received at the remote controller and stored in the remote controller memory as part of a database. The remote controller and the memory are configured to access and store data from multiple radiotherapy machines connected to the remote controller via a network, respectively. The received signals may take various forms. For example, a signal may be received periodically from either or both of the first sensor and the second sensor. In this example, the first pump periodically (e.g., every 4 seconds) transmits readings from the first sensor to the device controller, and the second pump transmits readings from the second sensor to the device controller.

[0122] The pressure value received at step 840 may be an average of signals received from either or both of the first sensor and the second sensor over a period of time. In other words, the pressure value may be an average pressure in the vacuum tube over the period of time. Preferably, the period of time is one week, so that the pressure value is a weekly average of the pressure in the vacuum tube. The method may also include deriving the pressure value by calculating or otherwise determining an average of signals received from either or both of the first sensor and the second sensor over the period of time.

[0123] At optional step 850, the pressure value is processed. In a preferred embodiment, the processing of the pressure value includes determining whether the pressure value satisfies at least one third threshold criterion. Optionally, this includes determining that the pressure value has fallen below a threshold pressure value, such as below -6.15 (5.03E-07 mBar).

[0124] Exceeding this threshold suggests that the vacuum system is not performing as well as it should, either due to cleanliness, vacuum leaks or a poorly performing pump. In summary, it indicates that vacuum quality is a possible cause of short gun life.

[0125] The pressure values ​​obtained for any particular radiotherapy device can be reviewed against the device's pressure value history. For example, if "Machine A" had a vacuum of -6.14 (5.19E-07 mBar) in August 2019, then checking the full vacuum history reveals that in August 2017, a pressure value was recorded as -6.35 (2.54E-07 mBar). Therefore, this machine is capable of better vacuum, so the possibility of improving the vacuum should be further investigated. If the value obtained is the same as the historical value, it may indicate that a longer maintenance activity will be spent to clean / purge the vacuum system.

[0126] By analyzing the history of the pressure values ​​of the installation, any seasonal variations in the pressure values ​​can be taken into account, with better pressure values ​​being recorded in the winter months and worse values ​​being recorded in the summer months. Vacuum systems tend to work better in cold conditions as contaminants are less likely to be disturbed. Typically the main contaminant will be water vapor. This is disturbed at higher temperatures and less reactive at low temperatures. Contaminants will also react when the beam is first turned on and the RF is sent down the waveguide, which can cause a vacuum spike before normalizing.

[0127] At step 860, based at least on the processing of the current value, it is determined whether maintenance of the radiotherapy apparatus should be scheduled. In an example, if the determination at steps 820 and 830 (and optionally 850) described above is affirmative, i.e., if the current value satisfies at least one threshold criterion and the total amount of time the electron gun is in radiation mode satisfies at least a second threshold criterion (and optionally the pressure value satisfies at least a third threshold criterion), then it is determined that maintenance of the radiotherapy apparatus should be scheduled.

[0128] At step 870, the determination of whether maintenance of the radiation therapy device should be scheduled at step 860 is output. This step is optional. Outputting the determination may include displaying an indication of the determination on a display screen. In response to the indication, maintenance of the radiation therapy device may be scheduled at the next available maintenance point or at a time convenient for the machine owner (e.g., during a planned machine downtime). Outputting the determination may also include issuing an alert or notification to a field maintenance engineer detailing the determination.

[0129] The alert may include information on how to test the radiotherapy device for vacuum leaks introduced after a previous replacement of the electron gun or contamination due to frequent gun changes and little adjustment time. The alert may also include how to repair the vacuum leak or how to perform a bake-out process to repair the contamination problem. The output determination may also include issuing a communication, alerting, or otherwise contacting the owner of the radiotherapy device to notify them of the problem and schedule maintenance of the radiotherapy device.

[0130] In an example, contamination may be detected by identifying a pressure value starting at a first value (e.g., -6.09 or 6.07E-07 mBar), then detecting a drop to a lower second value (e.g., -5.93 or 1.07E-06 mBar) after the radiotherapy device has heated up, as indicated by the increased water temperature. The electron gun then begins operating in radiation mode, the vacuum further degrades, and continues to degrade until the pressure value is detected to land at an even lower third value (e.g., -5.81 or 1.60E-06 mBar). This behavior is an indication of contamination because vacuum performance degrades as temperature increases.

[0131] In an example, a vacuum leak may be detected by identifying that the pressure value begins at a first value (e.g., -5.90 or 1.17E-06 mBar). Once the radiotherapy device has become hot and the electron gun has begun operating in radiation mode, a vacuum change that meets a threshold is detected (e.g., the change exceeds a certain minimum decrease in the pressure value, which may be, for example, a change of 0.10), and this indicates a vacuum leak. If the first value is -5.90 (1.17E-06 mBar), and after the machine has completed the first operation in radiation mode, if a pressure value between -5.80 (1.65E-06 mBar) and -5.90 (1.17E-06 mBar) is detected, this may indicate a vacuum leak. At this point the vacuum pressure value should be detected as less than -5.80 (1.65E-06 mBar). This may be a combination of a vacuum leak and contamination or more severe contamination.

[0132] In the example, once the conditions described herein have been met and Figure 8a and Figure 8b If the criteria described in the flowchart of the radiotherapy device are followed, a report is generated and an alert is issued. The alert is then sent to the relevant maintenance team, and they will plan the maintenance of the radiotherapy device.

[0133] In a preferred embodiment, the device controller 240 receives signals from the current sensor and one or both of the first sensor and the second sensor and transmits them to the remote controller 260. The central controller 270 receives the signals and then derives the current value, for example, by calculating the average current value from the signal over a period of time, and derives the pressure value, for example, by calculating the average pressure value from the signal over a period of time. The average current value and the average pressure value are stored on the central controller memory 270. Then, when the remote controller 260 accesses the central memory 275 via the network 250, the current value and the pressure value are processed. However, Figure 8a and Figure 8b At least some of the steps shown in , and in some examples all of the steps, may be performed on the device controller 240. It should be understood that any combination of the device controller 240, the central controller 270, and the remote controller 260 may be used to perform the disclosed methods.

[0134] Reference now Figure 9a and Figure 9b The method may be described in the flowchart of FIG. The method may start from optional step 910 or step 920. At optional step 910, a notification of a fault in a radiotherapy device is received. The radiotherapy device may be a LINAC device. The notification may indicate that the radiotherapy device has begun to operate outside of its normal operating parameters. The generation of the notification may be related to Fig.10A more detailed description is given below. When one or more conditions are met, the notification may be triggered. A possible condition that may lead to the issuance of a fault notification may be a determination that the received current value and / or the received second voltage value meet a third threshold and a fourth threshold, respectively.

[0135] At step 920, voltage values ​​during gantry rotation are received. This step may be performed in response to receiving a fault notification at step 310, or may be performed in other ways to begin the process of determining the nature of the fault. For example, the process may be manually initiated in response to an operator realizing that the radiotherapy machine has a fault. Preferably, during gantry rotation, a series of voltage values ​​are taken at various points in the gantry rotation while the electron gun is in an inactive or standby mode. In this way, any changes in the received voltage values ​​across gantry rotations may then be identified as follows.

[0136] A signal is received from a voltage sensor 237 during rotation of the gantry. As described in detail elsewhere herein, the voltage sensor 237 is configured to provide a signal indicative of a voltage applied to the electron gun. The signal is processable to provide a voltage value indicative of the voltage applied to the electron gun at various points in time during rotation of the gantry. The voltage value is derived from the signal from the voltage sensor in any manner disclosed herein.

[0137] The signal is received at one or more of the device controller and the remote controller. For example, the signal may be received at the device controller and stored in the device controller memory as part of a database / log of signals received from that particular radiation therapy machine. The device controller memory also stores a record of any faults identified by the device controller.

[0138] The signal may also be received at the remote controller and stored in the remote controller memory as part of a database. The remote controller and the memory are configured to access and store data from multiple radiotherapy machines connected to the remote controller via a network, respectively. The received signal may take various forms. For example, the signal may be received periodically from a voltage sensor. In this example, the voltage sensor transmits a signal to the device controller periodically (e.g., every 4 seconds during gantry rotation).

[0139] At step 930, the voltage value is processed. In a preferred embodiment, the processing of the voltage value includes determining whether the voltage value satisfies at least one first threshold criterion. Optionally, this includes determining whether the voltage value changes by at least a threshold amount, such as by 0.2V, during the rotation of the gantry. Optionally, this includes determining whether the voltage value changes by at least a threshold amount of 0.05V. This change in the voltage value indicates movement of one or more components of the electron gun during the rotation of the gantry due to the effect of gravity on the loose components. For example, a loose carrier of the cathode of the electron gun may cause a change in the voltage value. There may also be loose connections on the gun body or problems with the gun isolation transformer that cause the determined voltage change.

[0140] Exceeding the first threshold indicates that the resistance of the filament of the electron gun cathode varies during gantry rotation, and the higher the variation, the more likely the machine is unstable during clinical treatment.

[0141] At optional step 940, the voltage value is processed, this time to determine whether the electron gun is in standby mode during gantry rotation by determining whether the voltage value satisfies at least one second threshold criterion. Optionally, this includes determining whether the voltage value is less than a first threshold voltage value, such as 15V.

[0142] At optional step 950, a gantry angle value derived from a signal provided by a gantry rotation sensor is received for each received voltage value.

[0143] The signal is received from a gantry rotation sensor. As described in detail elsewhere herein, the gantry rotation sensor is configured to provide a signal indicating the extent to which the gantry has been rotated. The signal is processable to provide a gantry angle value indicating the extent to which the gantry has been rotated.

[0144] The signal is received at one or more of the device controller and the remote controller. For example, the signal may be received at the device controller and stored in the device controller memory as part of a database / log of signals received from that particular radiation therapy machine. The device controller memory also stores a record of any faults identified by the device controller.

[0145] The signal may also be received at the remote controller and stored in the remote controller memory as part of a database. The remote controller and the memory are configured to access and store data from a plurality of radiotherapy machines connected to the remote controller via a network, respectively. The received signal may take various forms. For example, a signal may be received periodically from a gantry rotation sensor. In this example, the gantry rotation sensor transmits a signal to the device controller periodically (e.g., every 4 seconds). Alternatively, a signal may be received whenever a voltage sensor transmits a signal to the device controller to provide a gantry angle value corresponding to a voltage value derived from a signal provided by the voltage sensor. In this way, each voltage value is provided with a corresponding gantry angle value.

[0146] At optional step 960, the gantry angle value is processed. In a preferred embodiment, the processing of the gantry angle value includes determining whether the rotation of the gantry has satisfied at least one fifth threshold criterion. Optionally, this includes determining whether the rotation of the gantry exceeds a threshold rotation degree, such as 90 degrees. Optionally, this includes determining whether the rotation of the gantry exceeds a threshold rotation degree, such as 360 degrees.

[0147] At step 970, based at least on the processing of the voltage value, it is determined whether the nature of the fault is associated with the electron gun. In an example, if the determination of steps 930 (and optionally 940 and 960) above is affirmative, i.e., if the voltage value satisfies at least the first threshold criterion (and optionally, the voltage value satisfies at least the second threshold criterion and / or the rotation of the gantry has satisfied at least the fifth threshold criterion), then it is determined that the nature of the fault is associated with the electron gun.

[0148] At step 980, a determination is output as to whether the nature of the fault at step 970 is associated with the electron gun. This step is optional. Outputting the determination may include displaying an indication of the determination on a display screen. In response to the indication, maintenance of the radiotherapy device may be scheduled at the next available maintenance point or at a time convenient for the machine owner (e.g., during a planned machine downtime) to repair the fault. Outputting the determination may also include issuing an alert or notification detailing the determination to a field maintenance engineer.

[0149] The alert may include information on how to identify if a carrier for a cathode of an electron gun is loose or if there is a loose connection on the gun body or a problem with the gun isolation transformer. The alert may also include how to repair these problems. The output determination may also include sending a communication, alerting, or otherwise contacting the owner of the radiotherapy device to notify them of the problem and arrange for maintenance of the radiotherapy device.

[0150] In the example, once the conditions described herein have been met and Figure 9a and Figure 9bIf the criteria described in the flowchart of the radiotherapy device are followed, a report is generated and an alert is issued. The alert is then sent to the relevant maintenance team, and they will plan the maintenance of the radiotherapy device.

[0151] In a preferred embodiment, the device controller 240 receives signals from the voltage sensor and the gantry rotation sensor and transmits them to the remote controller 260. The central controller 270 receives the signals and then derives voltage values ​​and gantry angle values. The voltage values ​​can be derived by calculating an average voltage value from the signals over a period of time to determine whether the sensor remains at the same gantry angle during the period of time. Each average voltage value and the corresponding gantry angle value are stored in the central controller memory 270. The voltage values ​​and gantry angle values ​​are then processed when the remote controller 260 accesses the central memory 275 via the network 250. However, Figure 9a and Figure 9b At least some of the steps shown in , and in some examples all of the steps, may be performed on the device controller 240. It should be understood that any combination of the device controller 240, the central controller 270, and the remote controller 260 may be used to perform the disclosed methods.

[0152] Reference now Fig.10 The flowchart shows how the fault notification in step 910 is generated. The process identifies a short circuit or partial short circuit in the electron gun, which may indicate that the electron gun or a component of the electron gun has become loose.

[0153] At step 1010, a current value is received. The current value is derived from a signal from a current sensor. The current value may directly indicate the signal from the current sensor in any particular case, and may change as the signal from the current sensor changes. To this end, the current value may be continuously updated.

[0154] At step 1020, the current value is processed. In a preferred embodiment, the processing of the current value includes determining whether the current value meets at least a third threshold criterion. Optionally, this includes determining that the current value has dropped below a threshold current value, such as below 1A.

[0155] At step 1030, a voltage value is received. The voltage value is derived from a signal from a voltage sensor. The voltage value may directly indicate the signal from the voltage sensor in any particular case, and may change as the signal from the voltage sensor changes. To this end, the voltage value may be continuously updated.

[0156] At step 1040, the voltage value is processed. In a preferred embodiment, the processing of the voltage value includes: determining whether the voltage value meets at least a fourth threshold criterion. Optionally, this includes: determining that the voltage value is greater than a second threshold voltage value, such as greater than 35A.

[0157] At step 1050, when one or both of the third threshold criteria and the fourth threshold criteria are met, a notification is generated indicating a fault in the radiotherapy apparatus. For example, if the current value has dropped below a threshold current value and / or the voltage value is greater than a second threshold voltage value, a notification indicating a fault in the radiotherapy apparatus may be generated. Meeting one or both of the third threshold criteria and the fourth threshold criteria may indicate that the electron gun or a component of the electron gun has become loose and caused a partial short circuit.

[0158] It should be understood that although Figure 5 , Figure 8a , Figure 8b , Figure 9a , Figure 9b and Fig.10 A specific order of steps is set forth in the , but the steps can be performed in a different order.

[0159] Examples of the disclosure are set forth in the following numbered clauses.

[0160] 1. A method of determining whether maintenance of a radiotherapy apparatus should be scheduled, the radiotherapy apparatus comprising a linear accelerator and configured to provide therapeutic radiation to a patient, the radiotherapy apparatus comprising:

[0161] a current sensor configured to provide a signal indicative of a current supplied to an electron gun of the radiation therapy apparatus; and

[0162] A vacuum tube, the vacuum tube comprising:

[0163] electron gun; and

[0164] a waveguide configured to accelerate electrons emitted by the electron gun toward the target to produce said radiation;

[0165] Methods include:

[0166] receiving a current value derived from a signal provided by a current sensor;

[0167] processing the current value to determine whether the current value satisfies at least a first threshold criterion;

[0168] determining whether a total amount of time the electron gun is in the radiation mode satisfies at least a second threshold criterion; and

[0169] If the first threshold criterion and the second threshold criterion are met, it is determined whether maintenance of the radiation therapy device should be scheduled.

[0170] 2. The method of clause 1, wherein determining whether the current value satisfies a first threshold criterion comprises determining that the current value has dropped below a threshold current value, optionally wherein the threshold current value is 7.35A.

[0171] 3. The method of any preceding clause, wherein the current value is an average value of a signal received from the current sensor over an averaging period, optionally wherein the averaging period is one day.

[0172] 4. The method of any preceding clause, wherein determining whether the total amount of time the electron gun is in the radiation mode satisfies a second threshold criterion comprises determining that the total amount of time the electron gun is in the radiation mode is less than a threshold time period, optionally wherein the time period is 600 hours.

[0173] 5. The method of any preceding clause, further comprising: outputting a determination of whether maintenance of the radiotherapy device should be scheduled.

[0174] 6. The method of clause 5, wherein outputting the determination comprises at least one of: displaying an indication of the determination on a display screen; issuing an alert detailing the determination to a field maintenance engineer; and / or automatically issuing a notification to an owner of the radiotherapy device to schedule maintenance of the radiotherapy device.

[0175] 7. The method of any preceding clause, the radiotherapy apparatus further comprising a pressure sensor configured to provide a signal indicative of the pressure inside the vacuum tube,

[0176] The method also includes:

[0177] receiving a pressure value derived from a signal from a pressure sensor, the pressure value indicating a pressure inside the vacuum tube;

[0178] processing the pressure value to determine whether the pressure value satisfies at least a third threshold criterion; and

[0179] If the third threshold criterion is met, a determination is made as to whether maintenance of the radiation therapy device should be scheduled.

[0180] 8. The method of clause 7, wherein determining whether the pressure value satisfies a third threshold criterion comprises determining that the pressure value has fallen below a threshold pressure value.

[0181] 9. The method of clause 7 or 8, wherein the pressure value is an average of signals received from the pressure sensor over an averaging period, optionally wherein the averaging period is seven days.

[0182] 10. A computer readable medium comprising computer executable instructions which, when executed by a processor, cause the processor to perform the method of any preceding clause.

[0183] 11. A system comprising a remote controller communicatively coupled to a central controller via a network, the central controller being configured to receive data from a radiation therapy apparatus, the radiation therapy apparatus comprising a linear accelerator and configured to provide therapeutic radiation to a patient, and the radiation therapy apparatus comprising:

[0184] a current sensor configured to provide a signal indicative of a current supplied to an electron gun of the radiation therapy apparatus; and

[0185] A vacuum tube, the vacuum tube comprising:

[0186] electron gun; and

[0187] a waveguide configured to accelerate electrons emitted by the electron gun toward the target to produce said radiation,

[0188] wherein the remote controller is coupled to a computer readable medium comprising computer executable instructions which, when executed by the remote controller, cause the remote controller to:

[0189] requesting a current value from a central controller; and

[0190] A method for performing any of clauses 1 to 6.

[0191] 12. The system of clause 11, wherein the radiation therapy apparatus further comprises a pressure sensor configured to provide a signal indicative of a vacuum quality of the vacuum tube,

[0192] When the computer executable instructions are executed by the remote controller, they also cause the remote controller to execute the method of any one of clauses 1 to 9.

[0193] 13. A method of determining the nature of a fault in a radiotherapy apparatus, the radiotherapy apparatus comprising a linear accelerator and being configured to provide therapeutic radiation to a patient, the radiotherapy apparatus comprising:

[0194] a gantry configured to rotate the vacuum tube about the patient so that radiation can be directed toward the patient from a plurality of angles and / or directions around the patient;

[0195] a voltage sensor configured to provide a signal indicative of a voltage applied to an electron gun of a radiation therapy apparatus; and

[0196] A vacuum tube, the vacuum tube comprising:

[0197] electron gun; and

[0198] A waveguide configured to accelerate electrons emitted by an electron gun toward a target to produce said radiation, the method comprising:

[0199] receiving a voltage value derived from a signal provided by a voltage sensor during rotation of the gantry;

[0200] Processing the voltage value, wherein processing the voltage value comprises: determining whether the voltage value satisfies at least one first threshold criterion;

[0201] as well as

[0202] Based on the processing of the voltage values, it is determined whether the nature of the fault is associated with the electron gun.

[0203] 14. The method of clause 13, wherein determining whether the voltage value satisfies at least one first threshold criterion comprises determining whether the voltage value changes by at least a threshold amount during rotation of the gantry.

[0204] 15. The method of clause 14, wherein the threshold amount is 0.2 volts.

[0205] 16. The method of any preceding clause, wherein processing the voltage value further comprises determining whether the electron gun is in a standby mode during rotation of the gantry by determining whether the voltage value satisfies at least one second threshold criterion.

[0206] 17. The method of clause 16, wherein determining whether the voltage value satisfies at least one second threshold criterion comprises determining whether the voltage value is less than a first threshold voltage value.

[0207] 18. The method of clause 17, wherein the first threshold voltage is 15 volts.

[0208] 19. The method of any preceding clause, the radiotherapy apparatus further comprising a gantry rotation sensor configured to provide a signal indicative of the extent to which the gantry has been rotated,

[0209] The method also includes:

[0210] receiving a gantry angle value derived from a signal provided by a gantry rotation sensor for each received voltage value, wherein each gantry angle value indicates the degree to which the gantry was rotated when the respective voltage value was generated; and

[0211] The gantry angle value is processed to determine whether the rotation of the gantry has satisfied at least one fifth threshold criterion.

[0212] 20. The method of clause 19, wherein determining whether the rotation of the gantry has satisfied a fifth threshold criterion comprises determining whether the rotation of the gantry exceeds a threshold degree of rotation, optionally wherein the degree of rotation is 90 degrees.

[0213] 21. The method of any preceding clause, further comprising: outputting a determination as to whether the nature of the fault is associated with the electron gun.

[0214] 22. The method of clause 21, wherein outputting the determination comprises at least one of: displaying an indication of the determination on a display screen; issuing an alert to a field maintenance engineer detailing the determination; and / or automatically issuing a notification to an owner of the radiotherapy device to arrange for repair or replacement.

[0215] 23. The method of any preceding clause, further comprising: receiving or generating a notification of a fault in the radiotherapy device.

[0216] 24. The method of any one of clauses 13 to 22, the radiotherapy apparatus further comprising a current sensor configured to provide a signal indicative of a current supplied to the electron gun,

[0217] The method also includes:

[0218] receiving a current value derived from a signal provided by a current sensor;

[0219] processing the current value, wherein processing the current value comprises: determining whether the current value satisfies at least a third threshold criterion;

[0220] receiving a second voltage value derived from a signal provided by the sensor; and

[0221] processing the second voltage value, wherein processing the second voltage value comprises: determining whether the second voltage value satisfies at least a fourth threshold criterion;

[0222] Based on the process current value and the second voltage value, a notification of a fault in the radiation therapy apparatus is generated.

[0223] 25. The method of clause 24, wherein determining whether the current value satisfies at least a third threshold criterion comprises determining whether the current value is less than a threshold current, optionally wherein the threshold current is 1A.

[0224] 26. The method of clause 24 or 25, wherein determining whether the second voltage value satisfies at least a fourth threshold criterion comprises determining whether the second voltage is greater than a second threshold voltage, optionally wherein the second voltage threshold is 35V.

[0225] 27. A system comprising a remote controller communicatively coupled to a central controller via a network, the central controller configured to receive data from a radiation therapy apparatus, the radiation therapy apparatus comprising a linear accelerator and configured to provide therapeutic radiation to a patient, and the radiation therapy apparatus comprising:

[0226] a gantry configured to rotate the vacuum tube about the patient so that radiation can be directed toward the patient from a plurality of angles and / or directions around the patient;

[0227] a voltage sensor configured to provide a signal indicative of a voltage of an electron gun of a radiotherapy apparatus; and

[0228] A vacuum tube, the vacuum tube comprising:

[0229] electron gun; and

[0230] a waveguide configured to accelerate electrons emitted by the electron gun toward the target to produce said radiation,

[0231] wherein the remote controller is coupled to a computer readable medium comprising computer executable instructions which, when executed by the remote controller, cause the remote controller to:

[0232] requesting and receiving from the central controller a voltage value derived from a signal provided by a voltage sensor during rotation of the gantry; and

[0233] A method for performing any of clauses 13 to 23.

[0234] 28. The system of clause 27, wherein the radiation therapy apparatus further comprises a current sensor configured to provide a signal indicative of a current supplied to the electron gun,

[0235] Wherein, when the computer executable instructions are executed by the remote controller, they also cause the remote controller to execute the method of any one of clauses 13 to 18 and 21 to 26.

[0236] 29. The system of clause 27 or 28, wherein the radiotherapy apparatus further comprises a gantry rotation sensor configured to provide a signal indicative of the extent to which the gantry has been rotated,

[0237] Wherein, when the computer executable instructions are executed by the remote controller, they also cause the remote controller to execute the method of any one of clauses 13 to 26.

[0238] 30. A method of determining the nature of a fault in a radiotherapy apparatus, the radiotherapy apparatus comprising a linear accelerator and configured to provide therapeutic radiation to a patient, the radiotherapy apparatus comprising:

[0239] a current sensor configured to provide a signal indicative of a current applied to an electron gun of a radiotherapy apparatus;

[0240] a voltage sensor configured to provide a signal indicative of a voltage applied to the electron gun; and

[0241] A vacuum tube, the vacuum tube comprising:

[0242] Electron gun;

[0243] A waveguide configured to accelerate electrons emitted by an electron gun toward a target to produce said radiation, the method comprising:

[0244] receiving a current value derived from a signal provided by a current sensor;

[0245] processing the current value, wherein processing the current value comprises: determining whether the current value satisfies at least a first threshold criterion;

[0246] receiving a voltage value derived from a signal provided by a sensor; and

[0247] processing the voltage value, wherein processing the voltage value comprises: determining whether the voltage value satisfies at least a second threshold criterion;

[0248] Based on the process current value and voltage value, a notification of a fault in the radiation therapy apparatus is generated.

[0249] 31. The method of clause 30, wherein determining whether the current value satisfies at least a first threshold criterion comprises determining whether the current value is less than a current threshold, optionally wherein the current threshold is 1A.

[0250] 32. The method of clause 30 or 31, wherein determining whether the voltage value satisfies at least a second threshold criterion comprises determining whether the voltage is greater than a threshold voltage value, optionally wherein the threshold voltage value is 35V.

[0251] 33. A system comprising a remote controller communicatively coupled to a central controller via a network, the central controller configured to receive data from a radiation therapy apparatus, the radiation therapy apparatus comprising a linear accelerator and configured to provide therapeutic radiation to a patient, and the radiation therapy apparatus comprising:

[0252] a current sensor configured to provide a signal indicative of a current applied to an electron gun of a radiotherapy apparatus;

[0253] a voltage sensor configured to provide a signal indicative of a voltage of the electron gun; and

[0254] A vacuum tube, the vacuum tube comprising:

[0255] Electron gun;

[0256] a waveguide configured to accelerate electrons emitted by the electron gun toward the target to produce said radiation,

[0257] wherein the remote controller is coupled to a computer readable medium comprising computer executable instructions which, when executed by the remote controller, cause the remote controller to:

[0258] requesting and receiving from the central controller a voltage value derived from a signal provided by a voltage sensor during rotation of the gantry; and

[0259] A method for performing any of clauses 30 to 32.

[0260] 34. A computer readable medium comprising computer executable instructions which, when executed by a processor, cause the processor to perform any of the methods of clause 1.

[0261] All methods of the present disclosure may be described as computer-implemented methods. As described herein, repair of an electron gun may include replacement of a cathode filament. Thus, the present technology describes a cost-effective, efficient, and predictive method of preventing failures. To date, it has proven impossible to determine the state of an electron gun in service in order to predict when maintenance should be performed. The present method saves cost and time over existing methods because repairs and maintenance in the form of repairs and replacements of electron guns or other components of a radiotherapy device are performed only when necessary, and reduces device downtime by reducing or completely eliminating the number of safety interruptions typically associated with a degraded cathode filament, and also by eliminating the time spent diagnosing problems before repairs are implemented.

[0262] The above implementations are described only by way of example, and the described implementations and arrangements should be considered in all respects to be illustrative rather than restrictive. It should be understood that the described implementations and arrangements may be varied without departing from the scope of the present invention.

Claims

1. A system for determining whether repair or replacement of an electron gun of a radiotherapy apparatus should be scheduled, the radiotherapy apparatus being configured to provide therapeutic radiation to a patient, the system comprising: The radiotherapy device comprises: Linear accelerator; A vacuum tube, comprising: the electron gun; a waveguide configured to accelerate electrons emitted by the electron gun toward a target to produce the radiation; and a current sensor configured to provide a signal indicative of a current supplied to the electron gun; A processor, the processor being configured to: receiving a current value derived from the signal provided by the current sensor; Processing the current value, wherein processing the current value comprises: if the current value has fallen below a first threshold current value, determining whether the current value has changed by a first threshold amount within a specified period of time; If the current value has not fallen below the first threshold current value, determining whether the current value has fallen below a second threshold current value; and if the current value has fallen below a second threshold current value, determining whether the current value has changed by a second threshold amount within the specified time period; wherein the first threshold current value is less than the second threshold current value, and the first threshold amount is less than the second threshold amount; and If the current value has dropped below the first threshold current value and has changed by at least the first threshold amount within the specific time period; or if the current value has dropped below the second threshold current value and has changed by at least the second threshold amount within the specific time period, it is determined that repair or replacement of the electron gun should be scheduled.

2. The system according to claim 1, characterized in that The current value is an average value of a plurality of signals received from the current sensor over an averaging period, wherein the averaging period is one day.

3. The system according to claim 2, characterized in that The processor is further configured to derive the current value based on the plurality of signals received from the current sensor, wherein the deriving includes calculating an average value of the plurality of signals received from the current sensor over the averaging period.

4. The system according to claim 1, characterized in that The processor is further configured to output the determination of whether repair or replacement of the electron gun should be scheduled, wherein outputting the determination comprises at least one of: displaying an indication of the determination on a display screen; issuing an alert to a field maintenance engineer detailing the determination; or automatically issuing a notification to an owner of the radiotherapy device to schedule the repair or replacement.

5. The system according to claim 1, further comprising: In response to determining that the current value has fallen below the second threshold current value and the current value has changed by the second threshold amount within the specific period of time, an indication that the electron gun should be repaired or replaced is output as a high priority.

6. A method of determining whether repair or replacement of an electron gun of a radiotherapy apparatus should be scheduled, the radiotherapy apparatus comprising a linear accelerator and configured to provide therapeutic radiation to a patient, the radiotherapy apparatus comprising: a vacuum tube including the electron gun, a waveguide configured to accelerate electrons emitted by the electron gun toward a target to generate the radiation; and a current sensor configured to provide a signal indicative of a current supplied to the electron gun; The method comprises: Receive current value; Processing the current value, wherein processing the current value comprises: if the current value has fallen below a first threshold current value, determining whether the current value has changed by a first threshold amount within a specified period of time; If the current value has not fallen below the first threshold current value, determining whether the current value has fallen below a second threshold current value; and if the current value has fallen below a second threshold current value, determining whether the current value has changed by a second threshold amount within the specified time period; wherein the first threshold current value is less than the second threshold current value, and the first threshold amount is less than the second threshold amount; and If the current value has dropped below the first threshold current value and has changed by at least the first threshold amount within the specific time period; or if the current value has dropped below the second threshold current value and has changed by at least the second threshold amount within the specific time period, it is determined that repair or replacement of the electron gun should be scheduled.

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