Beam-out beam safety control system and flash radiotherapy equipment

Abstract

This utility model discloses a beam exit safety control system, including an electron gun, an accelerating tube connected to the electron gun, a microwave source providing microwaves to the electron gun, and a power supply system providing power to the microwave source and the electron gun. A dose monitoring system connected to the power supply system is provided on one side of the beam exit end of the accelerating tube, and a beam deflection device is provided between the dose monitoring system and the beam exit end of the accelerating tube. This utility model has reliable and rapid-response safety redundancy measures to ensure the safety of patients undergoing radiotherapy.

Description

Technical Field

[0001] This utility model relates to the field of medical equipment technology, and in particular to a beam outflow safety control system and a Flash radiotherapy device. Background Technology

[0002] While flash radiotherapy can effectively kill tumor tissue while reducing toxic side effects on normal tissue, excessive doses can still cause irreversible damage to normal tissue. To ensure that tumor tissue receives as much radiation as possible while normal tissue receives as little as possible, traditional accelerators use dose monitoring methods, such as the ionization chamber of a dose monitoring system, to monitor the dose and stop beam emission when the dose reaches the set value in the treatment plan. This dose monitoring system mainly consists of two parts: the ionization chamber and the electronics module. The main function of the ionization chamber is to collect positive and negative ion pairs generated by the interaction between the beam and the gas medium inside the ionization chamber. The electronics module converts the current signal collected by the ionization chamber into dose rate and dose values. When the dose monitoring system detects that the dose is greater than or equal to the radiation dose given in the radiotherapy plan, it sends a beam-stop command to the accelerator's power system, thus ensuring the accuracy of dose administration. Simultaneously, the electronics module also has a beam emission time protection channel to protect the beam from being shut down if the dose has not reached the radiation dose given in the radiotherapy plan within the specified time, also by sending a beam-stop command to the accelerator's power system.

[0003] However, this method may pose safety risks in Flash radiotherapy. The main reasons are as follows: (1) The average dose rate or instantaneous dose rate of Flash radiotherapy is quite high, and the single pulse dose is relatively high. There is a certain time interval between the dose monitoring system issuing the command to shut down the radiation beam after detecting that the absorbed dose has reached the treatment plan setting value and the shutdown of the radiation beam. This may cause the absorbed dose of normal tissues to exceed the tolerance limit. (2) During the treatment process, the dose monitored by the dose monitoring system serves as the basis for beam shutdown. If this shutdown method fails or the shutdown command is not executed, the beam will continue to be emitted, and the patient may be exposed to a very large dose, such as tens or hundreds of times higher. (3) The status of the dose monitoring system serves as an accelerator interlocking mechanism. If this interlocking mechanism fails, the ultra-high dose rate beam will continue to irradiate the patient, and the patient's personal safety may be greatly threatened.

[0004] Therefore, existing technologies need further development to improve the safety redundancy of the radiotherapy process. Utility Model Content

[0005] To address the problems existing in the prior art, the purpose of this utility model is to provide a beam outflow safety control system and a Flash radiotherapy device. This utility model has reliable and rapid-response safety redundancy measures that can ensure the safety of patients during radiotherapy.

[0006] To achieve the above objectives, the technical solution adopted by this utility model is: a beam exit safety control system, including an electron gun, an accelerating tube connected to the electron gun, a microwave source that provides microwaves to the electron gun, and a power supply system that provides power to the microwave source and the electron gun. A dose monitoring system connected to the power supply system is provided on one side of the beam exit end of the accelerating tube. A beam deflection device is provided between the dose monitoring system and the beam exit end of the accelerating tube.

[0007] As a further improvement of this utility model, the dose monitoring system includes an ionization chamber and an electronics module connected by signal connection, and the electronics module is connected by signal connection to the power supply system and the beam deflection device respectively.

[0008] As a further improvement of this utility model, the dose monitoring system is used to monitor the absorbed dose and the actual beam exit time; the ionization chamber is used to collect current signals and transmit the current signals to the electronics module; the electronics module is used to calculate the current absorbed dose and the actual beam exit time. When the absorbed dose is greater than or equal to the absorbed dose value set in the treatment plan or when the actual beam exit time is greater than or equal to the beam exit time set in the treatment plan, the electronics module sends a beam stop command to the power supply system to cut off the power supply to the electron gun and the microwave source, thereby stopping the beam; at the same time, it sends a shutdown signal to the beam deflection device to deflect the high-energy electron beam.

[0009] As a further improvement of this utility model, the beam deflection device includes a first electrode plate and a second electrode plate arranged in parallel around the high-energy electron beam, and one of the electrode plates is connected to the deflection power supply, which is signal-connected to the electronics module.

[0010] As a further improvement of this utility model, a protective cylinder or protective plate is provided around the first electrode plate and the second electrode plate, which is used to block the high-energy electron beam after it is deflected.

[0011] As a further improvement of this utility model, the beam deflection device includes a deflection coil connected to a deflection power supply, and the magnetic field generated by the deflection coil is not parallel to the transmission direction of the high-energy electron beam. The deflection power supply is signal connected to the electronics module.

[0012] As a further improvement of this utility model, a protective cylinder or protective plate is provided around the deflection coil, which is used to block the high-energy electron beam after deflection.

[0013] As a further improvement of this utility model, a beam exit time recording module is provided between the beam exit end of the accelerating tube and the beam deflection device, and the beam exit time recording module is connected to the deflection power supply signal.

[0014] As a further improvement of this utility model, the protective cylinder or protective plate is made of aluminum, graphite, lead or plexiglass.

[0015] This utility model also provides a Flash radiotherapy device, including the beam outflow safety control system described above.

[0016] The beneficial effects of this utility model are:

[0017] This invention prevents patients from being over-exposed by adding electric and magnetic fields and other safety redundancy measures to the beam transmission path, thus ensuring patient safety. Moreover, this safety measure is rapid and reliable. Attached Figure Description

[0018] Figure 1 This is a schematic diagram of the structure of the beam deflection device generating the electric field in an embodiment of this utility model;

[0019] Figure 2 for Figure 1 A schematic diagram of the structure of the medium-current deflection device;

[0020] Figure 3 This is a schematic diagram of the structure of the beam exit time recording module in an embodiment of the present invention;

[0021] Figure 4 This is a schematic diagram of the structure of the beam deflection device generating the magnetic field in an embodiment of this utility model;

[0022] Figure 5 for Figure 4 A schematic diagram of the structure of the medium beam deflection device.

[0023] Figure label:

[0024] 1. Electron gun, 2. Accelerating tube, 3. Microwave source, 4. Power supply system, 5. Beam deflection device, 51. First electrode plate, 52. Second electrode plate, 53. Protective cylinder, 54. Deflection power supply, 55. Beam exit time recording module, 6. Dose monitoring system, 61. Ionization chamber, 62. Electronics module, 7. High-energy electron beam, 8. Deflection coil. Detailed Implementation

[0025] The embodiments of this utility model will now be described in detail with reference to the accompanying drawings.

[0026] Example 1

[0027] like Figure 1As shown, a beam exit safety control system mainly incorporates electric field-based safety redundancy. The beam stop command originates from the dose monitoring system. The electron gun 1 emits a low-energy electron beam, which is accelerated into a high-energy electron beam 7 by the accelerating tube 2. The high-energy electron beam 7 passes through the ionization chamber 61 in the dose monitoring system 6. The ionization chamber 61 collects relevant current signals and transmits these signals to the electronics module 62 within the dose monitoring system 6. This module calculates the current absorbed dose and the actual beam exit time. When the absorbed dose is greater than or equal to the absorbed dose value set in the treatment plan, or when the actual beam exit time is greater than or equal to the beam exit time set in the treatment plan, the electronics module 62 issues a beam stop command to the power supply system 4. The power supply system 4 then cuts off the power supply to the electron gun 1 and the microwave source 3, thereby stopping the beam. The microwave source 3 can be a magnetron or a klystron. The main function of the microwave source 3 is to provide microwaves to the accelerating tube 2.

[0028] Because the single-pulse dose is relatively high in Flash mode, a beam deflection device 5 is added to the front end of the ionization chamber 61 to ensure reliable dose shut-off in case the beam stop command fails. Its purpose is to generate an electric field to deflect the high-energy electron beam 7 when the absorbed dose is greater than or equal to the absorbed dose value set in the treatment plan, or when the actual beam exit time is greater than or equal to the beam exit time set in the treatment plan. The control process is as follows: When the electronics module 62 calculates that the absorbed dose is greater than or equal to the absorbed dose value set in the treatment plan, or when the beam exit time channel of the electronics module 62 records that the actual beam exit time is greater than or equal to the beam exit time set in the treatment plan, the electronics module 62 sends a beam stop command to the power system 4 and also sends a shutdown signal to the beam deflection device 5. After receiving the shutdown signal, the beam deflection device 5 deflects the high-energy electron beam 7 using an electric field.

[0029] Specifically, such as Figure 2 As shown, the beam deflection device 5 includes a first electrode plate 51, a second electrode plate 52, a protective cylinder 53, and a deflection power supply 54. When the deflection power supply 54 receives a beam-stopping command from the electronics module 62, it directly supplies power to the second electrode plate 52, establishing an electric field between the first electrode plate 51 and the second electrode plate 52. If conventional methods fail to effectively shut off the electron beam, this electric field will change the transmission direction of the high-energy electron beam 7. The deflected high-energy electron beam 7 will be blocked by the protective cylinder 53 surrounding the electrode plates, thereby achieving the purpose of beam cutoff. The protective cylinder 53 can be made of aluminum, graphite, lead, or plexiglass, thus preventing the generation of excessive X-rays after the protective cylinder 53 blocks the electron beam.

[0030] The protective cylinder 53 can also be configured as a protective plate, with its specific location remaining around the first electrode plate 51 and the second electrode plate 52. For X-ray accelerators, the beam deflection device 5 should be installed in front of the X-ray target.

[0031] Example 2

[0032] A beam exit safety control system primarily incorporates electric field-based safety redundancy, with beam stop commands originating from independent time protection elements. During accelerator operation, although the ionization chambers in the dose monitoring system 6 are dual-configured, simultaneous failure is still possible. For example, the gaseous environment of the ionization chambers might be disrupted, preventing the two ionization chambers from cross-checking. Simultaneously, failure of the time protection function in the electronics module 62 could lead to severe overdose beam exit and uncontrollable beam emission. Especially in Flash mode, even millisecond-level timeouts could result in overdose.

[0033] Therefore, this embodiment also includes an additional beam exit time recording module 55 compared to embodiment 1. For example... Figure 3 As shown, the beam exit time recording module 55 receives the beam exit time from the treatment plan module. When the electron beam passes through the beam exit time recording module 55, it records the cumulative beam exit time. When the time recorded by the beam exit time recording module 55 reaches the beam exit time set in the treatment plan, it outputs a beam stop command to the deflection power supply 54. Similar to Embodiment 1, when the deflection power supply 54 receives the beam stop command, it directly supplies power to the second electrode plate 52, establishing an electric field between the first electrode plate 51 and the second electrode plate 52. If there is still an electron beam in the electron beam transmission path, the electric field will change the transmission direction of the electron beam. The deflected electron beam will be blocked by the protective sleeve 53 around the electrode plate, thereby achieving the purpose of beam cut-off. The beam exit time recording module 55 here can be acted as a beam position probe (BPM) or other device that can monitor beam transmission. It starts timing when a beam passes through and resets the recorded time to zero when the treatment ends.

[0034] It should be noted that the deflection power supply 54 will immediately cut off the beam current whether it receives a beam stop command from the dose monitoring system 6 or a beam stop command from the beam exit time recording module 55.

[0035] Example 3

[0036] A beam exit safety control system mainly adds a safety redundancy mechanism based on a magnetic field. This embodiment differs from Embodiments 1 and 2 in that the electric field mechanism of the beam deflection device 5 is replaced with a magnetic field mechanism, employing a deflection coil 8, such as... Figure 4 and Figure 5 As shown, the magnetic field generated by deflection coil 8 is not parallel to the direction of electron beam propagation.

[0037] Example 4

[0038] A Flash radiotherapy device includes a beamout safety control system as described in Example 1, Example 2 or Example 3.

[0039] The embodiments described above merely illustrate specific implementations of this utility model, and while the descriptions are detailed, they should not be construed as limiting the scope of this utility model patent. It should be noted that those skilled in the art can make various modifications and improvements without departing from the concept of this utility model, and these modifications and improvements all fall within the protection scope of this utility model.

Claims

1. A beam exit safety control system, comprising an electron gun, an accelerating tube connected to the electron gun, a microwave source providing microwaves to the electron gun, and a power supply system providing power to the microwave source and the electron gun, wherein a dose monitoring system connected to the power supply system is provided on one side of the beam exit end of the accelerating tube, characterized in that, A beam deflection device is provided between the dose monitoring system and the beam exit end of the acceleration tube.

2. The beam outflow safety control system according to claim 1, characterized in that, The dose monitoring system includes an ionization chamber and an electronics module connected to the signal network. The electronics module is connected to the power supply system and the beam deflection device, respectively.

3. The beam outflow safety control system according to claim 2, characterized in that, The dose monitoring system is used to monitor the absorbed dose and the actual beam exit time; the ionization chamber is used to collect current signals and transmit the current signals to the electronics module; the electronics module is used to calculate the current absorbed dose and the actual beam exit time. When the absorbed dose is greater than or equal to the absorbed dose value set in the treatment plan or when the actual beam exit time is greater than or equal to the beam exit time set in the treatment plan, the electronics module sends a beam stop command to the power supply system to cut off the power supply to the electron gun and microwave source, thereby stopping the beam; at the same time, it sends a shutdown signal to the beam deflection device to deflect the high-energy electron beam.

4. The beam outflow safety control system according to claim 3, characterized in that, The beam deflection device includes a first electrode plate and a second electrode plate arranged parallel to each other around the high-energy electron beam, and one of the electrode plates is connected to a deflection power supply, which is connected to the electronics module for signal connection.

5. The beam outflow safety control system according to claim 4, characterized in that, The first and second electrode plates are surrounded by a protective cylinder or protective plate, which is used to block the high-energy electron beam after it is deflected.

6. The beam outflow safety control system according to claim 3, characterized in that, The beam deflection device includes a deflection coil connected to a deflection power supply, and the magnetic field generated by the deflection coil is not parallel to the transmission direction of the high-energy electron beam. The deflection power supply is signal connected to the electronics module.

7. The beam outflow safety control system according to claim 6, characterized in that, The deflection coil is surrounded by a protective cylinder or plate, which is used to block the high-energy electron beam after it is deflected.

8. The beam outflow safety control system according to claim 4 or 6, characterized in that, A beam exit time recording module is provided between the beam exit end of the accelerating tube and the beam deflection device, and the beam exit time recording module is connected to the deflection power supply signal.

9. The beam outflow safety control system according to claim 5 or 7, characterized in that, The protective cylinder or protective plate is made of aluminum, graphite, lead, or plexiglass.

10. A Flash radiotherapy device, characterized in that, Includes the beam outflow safety control system as described in any one of claims 1-9.

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