Dose rate stabilizing circuit of medical low-energy accelerator

Abstract

The utility model discloses a dosage rate stabilizing circuit for a medical low-energy accelerator. The dosage rate stabilizing circuit comprises a main trigger module, a delay trigger module, a pulse microwave module, an electron generation module and a selection module, the main trigger module is used for providing trigger pulses for the pulse microwave module to enable the pulse microwave module to generate pulse high voltage; the delay trigger module is used for delaying the trigger pulse generated by the main trigger module to obtain two off-peak trigger pulses; the pulse microwave module is used for generating pulse microwaves under the action of the pulse high voltage so as to further accelerate the electrons generated by the electron generation module; the electron generation module is used for generating accelerated electrons; and the selection module is used for selecting the delay trigger module and the main trigger module to determine the trigger pulse of the electron generation module so as to control the dose rate. By arranging the delay trigger module and the selection module, the purpose of stabilizing the dosage rate is achieved, and the service life of the magnetron is prolonged.

Description

Technical Field

[0001] The utility model relates to the technical field of accelerators, in particular to a dose rate stabilization circuit for a medical low-energy accelerator. Background Art

[0002] In medical low-energy electron linear accelerators, radiotherapy plans are formulated based on the patient's condition and treatment needs. Dose rate stability directly impacts treatment implementation. An unstable dose rate can cause the actual radiation dose received to deviate from the plan, impacting treatment effectiveness. An unstable dose rate can also result in the patient receiving an excessively high or low radiation dose, increasing treatment risks and the likelihood of side effects. A stable dose rate ensures that patients receive the expected radiation dose during treatment, reducing treatment risks.

[0003] In summary, the stability of the accelerator dose rate has a significant impact on the effectiveness and safety of patient treatment. In the existing technology, the trigger frequency of the pulsed high voltage is controlled by dose rate feedback to achieve a stable dose rate output. Since the pulsed high voltage is the energy source of the magnetron, this will cause the magnetron to operate in an unstable state at all times, accelerate the aging of the magnetron, and greatly shorten the life of the magnetron. Summary of the Invention

[0004] In the prior art, the dose rate is output stably by controlling the trigger frequency of the pulsed high voltage, but this causes the magnetron to always operate in an unstable state, which accelerates the aging of the magnetron and greatly shortens the life of the magnetron.

[0005] To address the above problems, a dose rate stabilization circuit for a medical low-energy accelerator is proposed. The actual dose rate voltage is collected and compared with the set dose rate voltage to obtain the current dose rate. By setting a delay trigger module and a selection module, when the dose rate is too high, the delay trigger module is selected to trigger the electron generation module, thereby reducing part of the dose, so as to achieve the purpose of stabilizing the dose rate.

[0006] A medical low-energy accelerator dose rate stabilization circuit, comprising:

[0007] Main trigger module;

[0008] Delay trigger module;

[0009] Pulsed microwave module;

[0010] electron generation module;

[0011] Select the module;

[0012] The delay trigger module is electrically connected to the main trigger module;

[0013] The delay trigger module is electrically connected to the selection module;

[0014] The main trigger module is also electrically connected to the pulse microwave module and the selection module;

[0015] The selection module is also electrically connected to the electron generation module;

[0016] The main trigger module is used to provide a trigger pulse for the pulse microwave module to generate a pulse high voltage;

[0017] The delay trigger module is used to delay the trigger pulse generated by the main trigger module to obtain two trigger pulses with different peaks;

[0018] The pulse microwave module is used to generate pulse microwaves under the action of pulse high voltage to further accelerate the electrons generated by the electron generation module;

[0019] The electron generation module is used to generate accelerated electrons;

[0020] The selection module is used to select the delay trigger module and the main trigger module to determine the trigger pulse of the electron generation module to control the dose rate.

[0021] In conjunction with the medical low-energy accelerator dose rate stabilization circuit described in the present invention, in a first possible implementation manner, the pulse microwave module includes:

[0022] modulator;

[0023] Pulse transformer;

[0024] magnetron;

[0025] The modulator, pulse transformer and magnetron are electrically connected in sequence;

[0026] The modulator is used to generate pulse high voltage under the action of the trigger pulse, and the pulse high voltage drives the magnetron to generate pulse microwaves through a pulse transformer.

[0027] In conjunction with the medical low-energy accelerator dose rate stabilization circuit described in the present invention, in a second possible implementation, the electron generation module includes:

[0028] High voltage power supply;

[0029] electron gun;

[0030] The high voltage power supply is electrically connected to the electron gun;

[0031] The electron gun is used to generate an electron beam, and the high-voltage power supply is used to generate a pulse high voltage under the action of a trigger pulse to accelerate the electron beam.

[0032] In conjunction with the medical low-energy accelerator dose rate stabilization circuit described in the present invention, in a third possible implementation, the selection module includes:

[0033] Select the circuit;

[0034] Comparison circuit;

[0035] Acquisition circuit;

[0036] The acquisition circuit is used to convert the real-time current signal transmitted from the ionization chamber into a real-time voltage signal;

[0037] The comparison circuit is used to compare the real-time voltage signal with a set standard voltage signal to determine the actual dose rate;

[0038] The selection circuit selects the main trigger module and the delay trigger module according to the comparison result.

[0039] In combination with the third possible implementation manner of the present invention, in a fourth possible implementation manner, the acquisition circuit includes:

[0040] Filtering and amplifying unit;

[0041] Integration unit;

[0042] Amplification and adjustment unit;

[0043] The filtering and amplifying unit, the integrating unit and the amplifying and adjusting unit are electrically connected in sequence to convert the ionization chamber input current into an actual dose rate voltage.

[0044] In combination with the fourth possible implementation manner of the present utility model, in a fifth possible implementation manner, the comparison circuit includes:

[0045] Plastic unit;

[0046] Comparator unit;

[0047] The acquisition circuit is electrically connected to the comparator unit through the shaping unit.

[0048] In combination with the medical low-energy accelerator dose rate stabilization circuit described in the present invention, in a sixth possible implementation manner, the trigger pulse frequency generated by the main trigger module is 200 Hz-300 Hz.

[0049] In combination with the medical low-energy accelerator dose rate stabilization circuit described in the present invention, in a seventh possible implementation manner, the high-voltage power supply adopts a diode high-voltage electron gun power supply.

[0050] The medical low-energy accelerator dose rate stabilization circuit described in the present invention acquires the current dose rate by collecting the actual dose rate voltage and comparing it with the set dose rate voltage. By setting a delay trigger module and a selection module, when the dose rate is too high, the delay trigger module is selected to trigger the electron generation module, thereby reducing a portion of the dose, thereby achieving the purpose of stabilizing the dose rate. BRIEF DESCRIPTION OF THE DRAWINGS

[0051] In order to more clearly illustrate the technical solutions in the embodiments of the present invention, the following briefly introduces the drawings required for use in the description of the embodiments. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying any creative work.

[0052] Figure 1 This is a circuit connection diagram of a dose rate stabilization circuit for a medical low-energy accelerator in the present invention;

[0053] Figure 2 This is a circuit connection diagram of the pulse microwave module in the present utility model;

[0054] Figure 3 This is a schematic diagram of the circuit connection of the electron generation module in the present utility model;

[0055] Figure 4 This is a circuit connection diagram of the selection module in the present utility model;

[0056] Figure 5 This is a schematic diagram of the connection of electronic components of the acquisition circuit in the present utility model;

[0057] Figure 6 This is a schematic diagram of the connection of electronic components of the comparison circuit in the present utility model;

[0058] The names of the parts indicated by the numbers in the accompanying drawings are: 100 - main trigger module, 200 - delay trigger module, 300 - pulse microwave module, 310 - modulator, 320 - pulse transformer, 330 - magnetron, 400 - selection module, 410 - selection circuit, 420 - comparison circuit, 421 - shaping unit, 422 - comparator unit, 430 - acquisition circuit, 431 - filtering and amplifying unit, 432 - integration unit, 433 - amplification and adjustment unit. DETAILED DESCRIPTION

[0059] The following is a clear and complete description of the technical solutions of the present invention in conjunction with the accompanying drawings. Obviously, the embodiments described are only part of the embodiments of the present invention, not all of them. Based on the embodiments of the present invention, other embodiments obtained by ordinary technicians in this field without creative work are all within the scope of protection of the present invention.

[0060] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by those skilled in the art to which this invention pertains. The terms used herein in the specification of this invention are intended only to describe specific embodiments and are not intended to limit the invention. The term "and / or" as used herein includes any and all combinations of one or more of the associated listed items.

[0061] It should be noted that when an element is referred to as being “fixed on” or “disposed on” another element, it may be directly on the other element or indirectly on the other element. When an element is referred to as being “connected to” another element, it may be directly connected to the other element or indirectly connected to the other element.

[0062] It should be understood that the terms "length", "width", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside", "outside", etc., indicating the orientation or position relationship, are based on the orientation or position relationship shown in the accompanying drawings, and are only for the convenience of describing this application and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as a limitation on this application.

[0063] Furthermore, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of the technical features being referred to. Thus, a feature defined as "first" or "second" may explicitly or implicitly include one or more of the features. Throughout the description of this application, "plurality" means two or more, unless otherwise specifically defined.

[0064] In the prior art, the dose rate is output stably by controlling the trigger frequency of the pulsed high voltage. However, this causes the magnetron 330 to always operate in an unstable state, which accelerates the aging of the magnetron 330 and greatly shortens the life of the magnetron 330 .

[0065] Aiming at the above problems, a dose rate stabilization circuit for medical low-energy accelerator is proposed.

[0066] A medical low energy accelerator dose rate stabilization circuit, such as Figure 1 , Figure 1This is a circuit connection diagram of the medical low-energy accelerator dose rate stabilization circuit in the present invention; it includes a main trigger module 100, a delay trigger module 200, a pulse microwave module 300, an electron generation module, and a selection module 400; the delay trigger module 200 is electrically connected to the main trigger module 100; the delay trigger module 200 is electrically connected to the selection module 400; the main trigger module 100 is also electrically connected to the pulse microwave module 300 and the selection module 400; the selection module 400 is also electrically connected to the electron generation module; the main trigger module 100 is used to generate a pulse microwave Module 300 provides a trigger pulse, generating a pulsed high voltage. The delayed trigger module 200 is used to delay the trigger pulse generated by the main trigger module 100 to obtain two trigger pulses with staggered peaks. The pulse microwave module 300 is used to generate pulsed microwaves under the action of the pulsed high voltage to further accelerate the electrons generated by the electron generation module. The electron generation module is used to accelerate electrons. The selection module 400 is used to select the delayed trigger module 200 and the main trigger module 100 to determine the trigger pulse of the electron generation module to control the dose rate. By collecting the actual dose rate voltage and comparing it with the set dose rate voltage, the current dose rate is obtained. By setting the delayed trigger module 200 and the selection module 400, when the dose rate is too high, the delayed trigger module 200 is selected to trigger the electron generation module, thereby reducing a portion of the dose, thereby achieving the purpose of stabilizing the dose rate.

[0067] In the accelerator, electrons are generated by the electron gun, and the electron beam is accelerated under the action of the high-voltage pulse power supply of the electron gun, and then enters the accelerator tube. When the pulse microwave of the magnetron 330 is synchronized with the high-voltage pulse of the electron gun, the pulse microwave will further accelerate the electrons sent by the electron gun, and then the electrons hit the target to produce X-rays. When the pulse microwave of the magnetron 330 is not synchronized with the high-voltage pulse of the electron gun, no X-rays can be generated.

[0068] Furthermore, if Figure 2 , Figure 2 This is a circuit connection diagram of the pulse microwave module 300 in the present invention; the pulse microwave module 300 includes a modulator 310, a pulse transformer 320, and a magnetron 330; the modulator 310, the pulse transformer 320, and the magnetron 330 are electrically connected in sequence; the modulator 310 is used to generate a pulse high voltage under the action of a trigger pulse, and the pulse high voltage drives the magnetron 330 to generate a pulse microwave through the pulse transformer 320.

[0069] The main trigger module 100 provides a trigger for the modulator 310, controls the modulator 310 to generate pulsed high voltage, and the pulsed high voltage of the modulator 310 drives the magnetron 330 through the pulse transformer 320, so that the magnetron 330 generates pulsed microwaves. The pulsed microwave energy is injected into the accelerator tube to accelerate the electron target to produce X-rays.

[0070] The maximum dose rate Umax that the accelerator can output needs to be greater than the sum of the stabilized dose rate Uset and the maximum value of the dose rate fluctuation Ub, that is, Umax>(Uset+Ub).

[0071] The delayed trigger module 200 uses the main trigger module 100 as a source, and delays the trigger pulse for a period of time based on the main trigger module 100. The delay time is greater than the high-level duration of the pulse, so that the peaks of the two trigger waveforms are completely staggered to obtain a delayed trigger pulse.

[0072] Furthermore, if Figure 3 , Figure 3 This is a circuit connection diagram of the electron generation module in the utility model; the electron generation module includes a high-voltage power supply and an electron gun; the high-voltage power supply is electrically connected to the electron gun; the electron gun is used to generate an electron beam, and the high-voltage power supply is used to generate a pulsed high voltage under the action of a trigger pulse to accelerate the electron beam.

[0073] The high voltage power supply is triggered by the main trigger pulse or the delayed trigger pulse to generate pulsed high voltage, providing initial acceleration energy for the secondary gun electrons.

[0074] Furthermore, if Figure 4 , Figure 4 This is a circuit connection diagram of the selection module 400 in the present invention; the selection module 400 includes a selection circuit 410, a comparison circuit 420, and an acquisition circuit 430; the acquisition circuit 430 is used to convert the real-time current signal transmitted from the ionization chamber into a real-time voltage signal; the comparison circuit 420 is used to compare the real-time voltage signal with a set standard voltage signal to determine the actual dose rate; the selection circuit 410 selects the main trigger module 100 and the delay trigger module 200 based on the comparison result.

[0075] Specifically, if Figure 5 , Figure 5 Schematic diagram of the connection of electronic components of the acquisition circuit 430 in the present invention; the acquisition circuit 430 includes a filter amplifier unit 431, an integration unit 432, and an amplification and adjustment unit 433; the filter amplifier unit 431, the integration unit 432, and the amplification and adjustment unit 433 are electrically connected in sequence to convert the ionization chamber input current into an actual dose rate voltage.

[0076] The circuit structure diagram of the acquisition circuit 430 is as follows: Figure 5 The current signal collected from the ionization chamber enters the filtering and amplifying unit 431, which includes a capacitor C2, resistors (R1, R2), and an amplifier U1.

[0077] The integration unit 432 includes resistors (R3, R4, R7, R9, R10, R11), capacitors (C1, C3), and an amplifier U2A. The amplification adjustment unit 433 includes an amplifier U2B and resistors (R6, R8, R12, R13).

[0078] The dose rate acquisition circuit 430 filters, amplifies, and integrates the current signal from the ionization chamber to convert it into a stable voltage signal.

[0079] There is a proportional relationship between the voltage collected by the dose rate collection circuit 430 and the dose rate. When the set dose rate is known, the corresponding set dose rate voltage Vset can be calculated.

[0080] Specifically, if Figure 6 , Figure 6 4 is a schematic diagram of electronic component connections of the comparison circuit 420 in the present invention; the comparison circuit 420 includes a shaping unit 421 and a comparator unit 422; the acquisition circuit 430 is electrically connected to the comparator unit 422 via the shaping unit 421.

[0081] The circuit structure of the comparison circuit 420 is as follows: Figure 6 The shaping unit 421 includes a comparator U3, a resistor R15, and a capacitor C4. The comparator unit 422 includes resistors (R14, R16, R17) and a comparator U4.

[0082] Preferably, the trigger pulse frequency generated by the main trigger module 100 is 200HZ-300HZ.

[0083] Dose rate stabilization principle:

[0084] The set dose rate voltage Vset and the real-time collected dose rate voltage Vnow are simultaneously fed into comparator unit 422. When Vnow > the set dose rate voltage Vset, comparator unit 422 outputs a high level, and control selection module 400 selects the delayed trigger pulse from delayed trigger module 200 as the trigger source for the electron gun high-voltage power supply. At this point, because the pulsed microwaves from magnetron 330 are out of sync with the electron gun high-voltage pulses, no X-rays are generated, and the dose rate decreases accordingly. As the dose rate decreases, Vnow, collected by dose collection circuit 430, also decreases, while the set dose rate voltage Vset remains unchanged. When these two voltages are fed into comparator unit 422, comparator unit 422 outputs a low level, and control selection module 400 selects the trigger pulse from main trigger module 100 as the trigger source for the electron gun high-voltage power supply. At this point, because the pulsed microwaves from magnetron 330 are in sync with the electron gun high-voltage pulses, the accelerator operates at the maximum dose rate. This repetitive process achieves a stable dose rate.

[0085] The medical low-energy accelerator dose rate stabilization circuit of the present invention acquires the current dose rate by collecting the actual dose rate voltage and comparing it with the set dose rate voltage. By setting a delay trigger module and a selection module, when the dose rate is too high, the delay trigger module is selected to trigger the electron generation module, thereby reducing part of the dose, thereby achieving the purpose of stabilizing the dose rate.

[0086] The above are only preferred embodiments of the present invention and are not intended to limit the present invention. Any modifications, equivalent replacements, improvements, etc. made within the spirit and principles of the present invention should be included in the scope of protection of the present invention.

Claims

1. A medical low-energy accelerator dose rate stabilization circuit, characterized in that: include: Main trigger module; Delay trigger module; Pulsed microwave module; electron generation module; Select the module; The delay trigger module is electrically connected to the main trigger module; The delay trigger module is electrically connected to the selection module; The main trigger module is also electrically connected to the pulse microwave module and the selection module; The selection module is also electrically connected to the electron generation module; The main trigger module is used to provide a trigger pulse for the pulse microwave module to generate a pulse high voltage; The delay trigger module is used to delay the trigger pulse generated by the main trigger module to obtain two trigger pulses with different peaks; The pulse microwave module is used to generate pulse microwaves under the action of pulse high voltage to further accelerate the electrons generated by the electron generation module; The electron generation module is used to generate accelerated electrons; The selection module is used to select the delay trigger module and the main trigger module to determine the trigger pulse of the electron generation module to control the dose rate.

2. The medical low-energy accelerator dose rate stabilization circuit according to claim 1, characterized in that: The pulse microwave module comprises: modulator; Pulse transformer; magnetron; The modulator, pulse transformer and magnetron are electrically connected in sequence; The modulator is used to generate pulse high voltage under the action of a trigger pulse, and the pulse high voltage drives the magnetron to generate pulse microwaves through a pulse transformer.

3. The medical low-energy accelerator dose rate stabilization circuit according to claim 1, characterized in that: The electron generation module comprises: High voltage power supply; electron gun; The high voltage power supply is electrically connected to the electron gun; The electron gun is used to generate an electron beam, and the high-voltage power supply is used to generate a pulse high voltage under the action of a trigger pulse to accelerate the electron beam.

4. The medical low-energy accelerator dose rate stabilization circuit according to claim 1, characterized in that: The selection module includes: Select the circuit; Comparison circuit; Acquisition circuit; The acquisition circuit is used to convert the real-time current signal transmitted from the ionization chamber into a real-time voltage signal; The comparison circuit is used to compare the real-time voltage signal with a set standard voltage signal to determine the actual dose rate; The selection circuit selects the main trigger module and the delay trigger module according to the comparison result.

5. The medical low-energy accelerator dose rate stabilization circuit according to claim 4, characterized in that: The acquisition circuit includes: Filtering and amplifying unit; Integration unit; Amplification and adjustment unit; The filtering and amplifying unit, the integrating unit and the amplifying and adjusting unit are electrically connected in sequence to convert the ionization chamber input current into an actual dose rate voltage.

6. The medical low-energy accelerator dose rate stabilization circuit according to claim 5, characterized in that: The comparison circuit comprises: Plastic unit; Comparator unit; The acquisition circuit is electrically connected to the comparator unit through the shaping unit.

7. The medical low-energy accelerator dose rate stabilization circuit according to any one of claims 1 to 6, characterized in that: The trigger pulse frequency generated by the main trigger module is 200HZ-300HZ.

8. The medical low-energy accelerator dose rate stabilization circuit according to claim 3, characterized in that: The high voltage power supply adopts a diode high voltage electron gun power supply.

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