Dose control device and method for medical electron linear accelerator

Abstract

The application discloses a dose control device and method of a medical electronic linear accelerator, which comprises an electronic pulse generator, a microwave pulse generator, a control computer, a trigger pulse generator, a counting frequency divider, a dose counter, a switch, a first circuit, a second circuit and an ionization chamber; the output end of the trigger pulse generator is in communication connection with the input end of the dose counter through the counting frequency divider, the output end of the dose counter is in communication connection with the input end of the switch, and the output end of the switch is in communication connection with the input end of the electronic pulse generator through the first circuit; the output end of the trigger pulse generator is also in communication connection with the input end of the switch; and the output end of the trigger pulse generator is also in communication connection with the input end of the microwave pulse generator through the second circuit. The application has the advantages of simple structure, high reliability and the ability to realize meticulous, more accurate and more balanced dose distribution.

Description

Technical Field

[0001] This invention belongs to the field of medical equipment for radiotherapy technology, and specifically relates to a dose control device and method for a medical linear accelerator. Background Technology

[0002] A medical linear accelerator is a medical device that uses a pulsed microwave source to create an electric field in the cavity of an accelerating tube. The electric field of the accelerating tube accelerates the electrons emitted by the electron gun itself. The high-energy electrons, after being linearly accelerated by the electric field of the accelerating tube cavity, or the high-energy electrons bombard the target material to produce bremsstrahlung radiation for radiotherapy, are used in clinical routine electron beam or X-ray radiotherapy.

[0003] Electron linear accelerator radiotherapy requires precise dose control, as detailed below:

[0004] For arc therapy (ARC), the gantry continuously delivers radiation while rotating around the patient, requiring precise control of the angle and dose.

[0005] Intensity-modulated radiotherapy (IMRT) requires precise adjustment of the dose intensity within the radiation field, using computer-aided optimization programs to obtain the non-uniform intensity distribution within a single radiation field. Dynamic IMRT utilizes the relative movement of a pair of corresponding blades in a multi-leaf grating (MLC) to adjust the intensity within the radiation field. Currently, most IMRT treatments employ dynamic IMRT. Dynamic IMRT requires dose control.

[0006] For volumetric modulated arc therapy (VMAT), the accelerator incorporates a standard multileaf collimator (MLC), combining dynamic MLC with arc therapy (ARC) to achieve optimized dose distribution through a rotating beam. VMAT is a novel radiotherapy technique developed from conventional intensity-modulated radiotherapy (IMRT), capable of rotating and irradiating tumors within any angle range set in a single or multiple 360° arc. Unlike conventional IMRT, VMAT utilizes a high-speed dynamic multileaf collimator, continuously variable dose rate, and variable gantry rotation speed to deliver optimized, continuous single (or multiple) arc irradiations. Compared to IMRT, VMAT offers shorter treatment times, higher dose delivery efficiency, and better patient quality of care.

[0007] Therefore, precise dose control is of paramount importance for radiotherapy. Currently, there are two main methods for dose control in medical linear accelerators.

[0008] Method 1 uses a diode electron gun in the accelerating tube, with a dose counter controlling the number of high-voltage pulses from the varying microwave source. However, when the magnetron pulses change, the magnetron becomes unstable, and mode skipping causes high-voltage overcurrent and microwave arcing; thus, precise dose control is not possible.

[0009] Method two involves using a triode electron gun in the accelerating tube to control the microwave power and the injection current at the gate, thereby controlling the dose rate. However, using a triode electron gun increases cost, increases the length of the accelerating tube, and complicates the control circuitry. Summary of the Invention

[0010] To address the aforementioned technical problems, this invention proposes a dose control device and method for a medical linear accelerator.

[0011] To achieve the above objectives, the technical solution of the present invention is as follows:

[0012] On one hand, the present invention discloses a dose control device for a medical linear accelerator, comprising: an electronic pulse generator and a microwave pulse generator, wherein the electronic pulse generator is used to provide electronic pulses to the electron gun, the microwave pulse generator is used to provide microwave pulses to the accelerating tube, and the accelerating tube is a diode electron gun accelerating tube;

[0013] It also includes: a control computer, a trigger pulse generator, a counter frequency divider, a dose counter, a switch, a first circuit, a second circuit, and an ionization chamber;

[0014] The control computer is used to configure and set the trigger pulse frequency for the trigger pulse generator, configure and set the frequency division coefficient for the distributor, and configure and set the dose for the dose counter.

[0015] The trigger pulse generator is used to output multi-frequency signals;

[0016] The output of the trigger pulse generator is connected to the input of the dose counter via a frequency divider, the output of the dose counter is connected to the input of the on / off switch, and the output of the on / off switch is connected to the input of the electronic pulse generator via a first circuit.

[0017] The output of the trigger pulse generator is also communicatively connected to the input of the switch.

[0018] The output of the trigger pulse generator is also connected to the input of the microwave pulse generator via a second circuit.

[0019] The ionization chamber is used to detect the dose rate of the radiation emitted from the accelerating tube and send it to the dosing system; the dosing system is used to analyze the dose signal received from the ionization chamber and feed back the dose counting pulse to the dose counter.

[0020] Based on the above technical solution, the following improvements can be made:

[0021] As a preferred embodiment, the first circuit includes: a first frequency divider, which is used to configure the electronic pulse generator with a corresponding operating frequency.

[0022] As a preferred embodiment, the first circuit further includes: a first regulator, which is used to adjust and shape the delay of the trigger pulse;

[0023] The output of the switch is connected to the input of the electronic pulse generator in sequence through the first frequency divider and the first regulator.

[0024] As a preferred embodiment, the second circuit includes a second frequency divider, which is used to configure the microwave pulse generator with a corresponding operating frequency.

[0025] As a preferred embodiment, the second circuit includes: a second regulator, which is used to adjust and shape the delay of the trigger pulse;

[0026] The output of the trigger pulse generator is connected to the input of the microwave pulse generator via a second frequency divider and a second regulator.

[0027] As a preferred embodiment, the second circuit further includes: a modulator, which is used to perform high-voltage modulation on the trigger pulse so that it can trigger the microwave pulse generator to work;

[0028] The output of the trigger pulse generator is connected to the input of the microwave pulse generator in sequence through the second frequency divider, the second regulator, and the modulator.

[0029] Furthermore, on the other hand, the present invention also discloses a dose control method for a medical linear accelerator, which utilizes any of the above-mentioned metrology control devices for control, specifically including the following steps:

[0030] S1: Select the preset target dose;

[0031] S2: The control computer analyzes the preset target dose to obtain the set trigger pulse frequency of the trigger pulse generator, the set frequency division coefficient of the distributor, and the set dose of the dose counter, and sends them to the corresponding components;

[0032] S3: Complete beam exit preparation;

[0033] S4: The control computer sends an enable signal to the counter divider and dose counter;

[0034] S5: Trigger the pulse generator to send a pulse;

[0035] S6: The microwave pulse generator emits microwave pulses under the action of the second circuit;

[0036] The accelerating tube emits a beam of light.

[0037] S7: The ionization chamber detects the dose rate of the radiation emitted from the accelerating tube and sends it to the dosing system;

[0038] The dosing system feeds back the dose counting pulses to the dose counter;

[0039] S8: The dose counter starts this round of counting, the dose counter sends an enable signal to the switch, and the electronic pulse generator emits electronic pulses under the action of the first circuit;

[0040] When the dose counter reaches the set value for this round of counting, a prohibition signal is sent to the switch, and the electronic pulse generator stops working;

[0041] S9: The frequency divider counts periodically according to the predetermined frequency division. After reaching the predetermined count value, it sends a reset signal to the dose counter, and the dose counter starts a new round of counting. S8-S9 are repeated until the total dose is completed.

[0042] As the preferred option, S4 is specifically as follows:

[0043] S4: The control computer sends an enable signal to the counter frequency divider, dose counter, first regulator and second regulator.

[0044] This invention discloses a dose control device and method for a medical linear accelerator, which has the following beneficial effects:

[0045] First, this invention uses a diode electron gun accelerator tube, which, compared to a triode gun accelerator tube, reduces the length of the accelerator tube, effectively reducing the height of the accelerator treatment center from the ground, and is also low in cost.

[0046] Second, a dose counter is used to control the output of the electronic pulse generator.

[0047] Third, the set division coefficient received by the frequency divider is the dose control accuracy; adjusting the set division coefficient adjusts the dose control accuracy. For example, a set division coefficient of 100 means a dose rate error accuracy of 1%.

[0048] Fourth, the trigger pulse generator outputs a multi-frequency signal, which is used to control the dose counter via a counter frequency divider. The first frequency divider outputs the operating frequency corresponding to the electronic pulse generator, and the second frequency divider outputs the operating frequency corresponding to the microwave pulse generator, thereby achieving a more detailed, accurate, and balanced dose distribution.

[0049] Fifth, the beam output process of the acceleration tube is uninterrupted, and the microwave pulse generator operates continuously, avoiding instability in the operation of the microwave pulse generator.

[0050] Sixth, the overall control device has a simple layout and high reliability. Attached Figure Description

[0051] To more clearly illustrate the technical solutions of the embodiments of the present invention, the accompanying drawings used in the embodiments will be briefly introduced below. It should be understood that the following drawings only show some embodiments of the present invention and should not be regarded as a limitation on the scope. For those skilled in the art, other related drawings can be obtained based on these drawings without creative effort.

[0052] Figure 1 A circuit block diagram of a dose control device provided in an embodiment of the present invention.

[0053] Figure 2 A flowchart of a metering control method provided in an embodiment of the present invention. Detailed Implementation

[0054] The preferred embodiments of the present invention will now be described in detail with reference to the accompanying drawings.

[0055] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0056] Using ordinal numbers such as “first,” “second,” “third,” etc. to describe ordinary objects merely indicates different instances of similar objects and is not intended to imply that the objects being described must have a given order in time, space, sequence, or any other way.

[0057] Furthermore, the expression "includes" is an "open-ended" expression, which only means that the corresponding component exists and should not be interpreted as excluding additional components.

[0058] To achieve the objectives of this invention, some embodiments of a dose control device and method for a medical linear accelerator, such as... Figure 1 As shown, the dose control device includes: an electronic pulse generator, a microwave pulse generator, a control computer, a trigger pulse generator, a counter frequency divider, a dose counter, a switch, a first circuit, a second circuit, and an ionization chamber.

[0059] The electronic pulse generator is used to provide electronic pulses to the electron gun, serving as the pulse power supply for the electron gun.

[0060] The microwave pulse generator is used to provide microwave pulses to the accelerating tube, which is a diode electron gun accelerating tube.

[0061] The control computer is used to configure and set the trigger pulse frequency for the trigger pulse generator, configure and set the frequency division coefficient for the distributor, and configure and set the dose for the dose counter.

[0062] The trigger pulse generator is used to output multi-frequency signals;

[0063] The output of the trigger pulse generator is connected to the input of the dose counter via a frequency divider, the output of the dose counter is connected to the input of the on / off switch, and the output of the on / off switch is connected to the input of the electronic pulse generator via a first circuit.

[0064] The output of the trigger pulse generator is also communicatively connected to the input of the switch.

[0065] The output of the trigger pulse generator is also connected to the input of the microwave pulse generator via a second circuit.

[0066] The ionization chamber is used to detect the dose rate of the radiation emitted from the accelerating tube and send it to the dosing system; the dosing system is used to analyze the dose signal received from the ionization chamber and feed back the dose counting pulse to the dose counter.

[0067] To further optimize the implementation effect of the present invention, in some other embodiments, the remaining features are the same, except that the first circuit includes: a first frequency divider and a first regulator. The first frequency divider is used to configure the corresponding operating frequency for the electronic pulse generator, and the first regulator is used to adjust and shape the delay of the trigger pulse.

[0068] The output of the switch is connected to the input of the electronic pulse generator in sequence through the first frequency divider and the first regulator.

[0069] Furthermore, the second circuit includes: a second frequency divider, a second regulator, and a modulator. The second frequency divider is used to configure the corresponding operating frequency for the microwave pulse generator, the second regulator is used to adjust and shape the delay of the trigger pulse, and the modulator is used to perform high-voltage modulation on the trigger pulse so that it can trigger the microwave pulse generator to work.

[0070] The output of the trigger pulse generator is connected to the input of the microwave pulse generator in sequence through the second frequency divider, the second regulator, and the modulator.

[0071] Furthermore, the encoder on the large gantry is communicatively connected to the dose counter, and the encoder sends pulses representing the gantry rotation angle to the dose counter. The dose quantity for each angle unit is consistent, ensuring stable dose distribution for each angle unit according to treatment requirements.

[0072] Furthermore, in another aspect, embodiments of the present invention also disclose a dose control method for a medical linear accelerator, which utilizes the aforementioned disclosed metrology control device for control, specifically including the following steps:

[0073] S1: Select the preset target dose;

[0074] S2: The control computer analyzes the preset target dose to obtain the set trigger pulse frequency of the trigger pulse generator, the set frequency division coefficient of the distributor, and the set dose of the dose counter, and sends them to the corresponding components;

[0075] S3: Complete beam exit preparation;

[0076] S4: The control computer sends an enable signal to the counter frequency divider, dose counter, first regulator, and second regulator;

[0077] S5: Trigger the pulse generator to send a pulse;

[0078] S6: The microwave pulse generator emits microwave pulses under the action of the second circuit;

[0079] The accelerating tube emits a beam of light.

[0080] S7: The ionization chamber detects the dose rate of the radiation emitted from the accelerating tube and sends it to the dosing system;

[0081] The dosing system feeds back the dose counting pulses to the dose counter;

[0082] S8: The dose counter starts this round of counting, the dose counter sends an enable signal to the switch, and the electronic pulse generator emits electronic pulses under the action of the first circuit;

[0083] When the dose counter reaches the set value for this round of counting, a prohibition signal is sent to the switch, and the electronic pulse generator stops working;

[0084] S9: The frequency divider counts periodically according to the predetermined frequency division. After reaching the predetermined count value, it sends a reset signal to the dose counter, and the dose counter starts a new round of counting. S8-S9 are repeated until the total dose is completed.

[0085] This invention discloses a dose control device and method for a medical linear accelerator, which has the following beneficial effects:

[0086] First, the present invention uses a diode electron gun accelerator tube, which, compared with a triode gun accelerator tube, reduces the length of the accelerator tube, effectively reducing the height of the accelerator treatment center from the ground, and is also low in cost.

[0087] Second, a dose counter is used to control the output of the electronic pulse generator.

[0088] Third, the set division coefficient received by the frequency divider is the dose control accuracy; adjusting the set division coefficient adjusts the dose control accuracy. For example, a set division coefficient of 100 means a dose rate error accuracy of 1%.

[0089] Fourth, the trigger pulse generator outputs a multi-frequency signal, which is used to control the dose counter via a counter frequency divider. The first frequency divider outputs the operating frequency corresponding to the electronic pulse generator, and the second frequency divider outputs the operating frequency corresponding to the microwave pulse generator, thereby achieving a more detailed, accurate, and balanced dose distribution.

[0090] Fifth, the beam output process of the acceleration tube is uninterrupted, and the microwave pulse generator operates continuously, avoiding instability in the operation of the microwave pulse generator.

[0091] Sixth, the overall control device has a simple layout and high reliability.

[0092] The above embodiments are only for illustrating the technical concept and features of the present invention, and are intended to enable those skilled in the art to understand the content of the present invention and implement it. They should not be used to limit the scope of protection of the present invention. All equivalent changes or modifications made in accordance with the spirit and essence of the present invention should be covered within the scope of protection of the present invention.

Claims

1. A dose control device for a medical linear accelerator, comprising: An electronic pulse generator and a microwave pulse generator are provided, wherein the electronic pulse generator is used to provide electronic pulses to the electron gun, and the microwave pulse generator is used to provide microwave pulses to the accelerating tube, and the accelerating tube is a diode electron gun accelerating tube. Its features include: a control computer, a trigger pulse generator, a counter frequency divider, a dose counter, a switch, a first circuit, a second circuit, and an ionization chamber; The first circuit includes: a first frequency divider and a first regulator, wherein the first frequency divider is used to configure the corresponding operating frequency for the electronic pulse generator, and the first regulator is used to adjust and shape the delay of the trigger pulse; The second circuit includes: a second frequency divider, a second regulator, and a modulator. The second frequency divider is used to configure the corresponding operating frequency for the microwave pulse generator. The second regulator is used to adjust and shape the delay of the trigger pulse. The modulator is used to perform high-voltage modulation on the trigger pulse so that it can trigger the microwave pulse generator to work. The control computer is used to configure and set the trigger pulse frequency for the trigger pulse generator, configure and set the division coefficient for the counter frequency divider, and configure and set the dose for the dose counter. The trigger pulse generator is used to output a signal corresponding to the division multiple of the second frequency divider; The output of the trigger pulse generator is connected to the input of the dose counter via a frequency divider, the output of the dose counter is connected to the input of the on / off switch, and the output of the on / off switch is connected to the input of the electronic pulse generator via a first frequency divider and a first regulator in sequence. The output terminal of the trigger pulse generator is also communicatively connected to the input terminal of the switch. The output of the trigger pulse generator is connected to the input of the microwave pulse generator in sequence via a second frequency divider, a second regulator, and a modulator. The ionization chamber is used to detect the dose signal of the radiation emitted from the accelerating tube and send it to the dose system; the dose system is used to analyze the dose signal received from the ionization chamber and feed back the dose counting pulse to the dose counter.

2. The dose control device according to claim 1, wherein the dose control device performs dose control by means of the following steps: S1: Select the preset target dose; S2: The control computer analyzes the preset target dose to obtain the set trigger pulse frequency of the trigger pulse generator, the set frequency division coefficient of the distributor, and the set dose of the dose counter, and sends them to the corresponding components; S3: Complete beam exit preparation; S4: The control computer sends an enable signal to the frequency divider and dose counter; S5: Trigger the pulse generator to send a pulse; S6: The microwave pulse generator emits microwave pulses under the action of the second circuit; The accelerating tube emits a beam of light. S7: The ionization chamber detects the dose rate of the radiation emitted from the accelerating tube and sends it to the dosing system; The dosing system feeds back the dose counting pulses to the dose counter; S8: The dose counter starts this round of counting, the dose counter sends an enable signal to the switch, and the electronic pulse generator emits electronic pulses under the action of the first circuit; When the dose counter reaches the set value for this round of counting, a prohibition signal is sent to the switch, and the electronic pulse generator stops working; S9: The frequency divider counts periodically according to the predetermined frequency division. After reaching the predetermined count value, it sends a reset signal to the dose counter, and the dose counter starts a new round of counting. S8-S9 are repeated until the total dose is completed.

3. The dose control device according to claim 2, characterized in that, S4 specifically refers to: S4: The control computer sends an enable signal to the counter frequency divider, dose counter, first regulator and second regulator.

Images