CN111132440A - Multi-signal-source selection circuit of modulator and control method thereof - Google Patents
Multi-signal-source selection circuit of modulator and control method thereof Download PDFInfo
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- CN111132440A CN111132440A CN201911261242.5A CN201911261242A CN111132440A CN 111132440 A CN111132440 A CN 111132440A CN 201911261242 A CN201911261242 A CN 201911261242A CN 111132440 A CN111132440 A CN 111132440A
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- H—ELECTRICITY
- H05—ELECTRIC TECHNIQUES NOT OTHERWISE PROVIDED FOR
- H05H—PLASMA TECHNIQUE; PRODUCTION OF ACCELERATED ELECTRICALLY-CHARGED PARTICLES OR OF NEUTRONS; PRODUCTION OR ACCELERATION OF NEUTRAL MOLECULAR OR ATOMIC BEAMS
- H05H7/00—Details of devices of the types covered by groups H05H9/00, H05H11/00, H05H13/00
- H05H7/02—Circuits or systems for supplying or feeding radio-frequency energy
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- A—HUMAN NECESSITIES
- A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
- A61N—ELECTROTHERAPY; MAGNETOTHERAPY; RADIATION THERAPY; ULTRASOUND THERAPY
- A61N5/00—Radiation therapy
- A61N5/10—X-ray therapy; Gamma-ray therapy; Particle-irradiation therapy
- A61N5/1048—Monitoring, verifying, controlling systems and methods
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- A—HUMAN NECESSITIES
- A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
- A61N—ELECTROTHERAPY; MAGNETOTHERAPY; RADIATION THERAPY; ULTRASOUND THERAPY
- A61N5/00—Radiation therapy
- A61N5/10—X-ray therapy; Gamma-ray therapy; Particle-irradiation therapy
- A61N5/1077—Beam delivery systems
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- A—HUMAN NECESSITIES
- A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
- A61N—ELECTROTHERAPY; MAGNETOTHERAPY; RADIATION THERAPY; ULTRASOUND THERAPY
- A61N5/00—Radiation therapy
- A61N5/10—X-ray therapy; Gamma-ray therapy; Particle-irradiation therapy
- A61N2005/1085—X-ray therapy; Gamma-ray therapy; Particle-irradiation therapy characterised by the type of particles applied to the patient
- A61N2005/1089—Electrons
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- A—HUMAN NECESSITIES
- A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
- A61N—ELECTROTHERAPY; MAGNETOTHERAPY; RADIATION THERAPY; ULTRASOUND THERAPY
- A61N5/00—Radiation therapy
- A61N5/10—X-ray therapy; Gamma-ray therapy; Particle-irradiation therapy
- A61N2005/1092—Details
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- H—ELECTRICITY
- H05—ELECTRIC TECHNIQUES NOT OTHERWISE PROVIDED FOR
- H05H—PLASMA TECHNIQUE; PRODUCTION OF ACCELERATED ELECTRICALLY-CHARGED PARTICLES OR OF NEUTRONS; PRODUCTION OR ACCELERATION OF NEUTRAL MOLECULAR OR ATOMIC BEAMS
- H05H7/00—Details of devices of the types covered by groups H05H9/00, H05H11/00, H05H13/00
- H05H7/02—Circuits or systems for supplying or feeding radio-frequency energy
- H05H2007/022—Pulsed systems
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Abstract
The invention discloses a multi-signal-source selection circuit of a modulator and a control method thereof, wherein the multi-signal-source selection circuit comprises an upper computer, a control CPU, a signal source selection circuit and a plurality of signal source storage circuits which are connected in parallel; the number of the signal sources corresponds to the energy levels of the accelerators one by one, the upper computer is controlled to output accelerator energy level signals, the control CPU generates chip selection codes according to the energy level signals and sends the chip selection codes to the signal source selection circuit, the signal source selection circuit controls the corresponding signal sources to work according to the chip selection codes, and when the accelerators need to work at the high energy levels, the signal source selection circuit is controlled to select the signal sources with relatively low maximum repetition frequency and more charging pulses in each repetition period; when the accelerator needs to work at a low energy level, the signal source selection circuit is controlled to select a signal source with relatively high maximum repetition frequency and less charging pulse in each repetition period; the invention can improve the dosage rate of the low-energy end of the accelerator.
Description
Technical Field
The invention belongs to the technical field of electron linear accelerators applied to radiotherapy, and particularly relates to a multi-signal-source selection circuit of a modulator and a control method thereof.
Background
The medical electronic linear accelerator mainly comprises a modulator, a microwave source, an electron gun, an accelerating tube, a collimator and the like, wherein the modulator is a high-power strong-interference electric component. The modulator adopts a flyback charging transformer to charge a pulse forming network in the modulator is a safer and more reliable mode. The control circuit of the modulator has a solidified signal source which generates a set of pulse signals to control the primary energy storage of the charging transformer.
The maximum width of each charging pulse and the minimum interval between the pulses are limited due to the magnetic core characteristics of a charging transformer, the number of the charging pulses depends on the requirement of the highest energy level of an accelerator, and after the highest energy level of the accelerator is determined, the number of the charging pulses, the maximum width of a single pulse and the pulse interval time determine the maximum repetition frequency of the emission of the accelerator microwave source and the electron gun beam.
The size of the energy level is selected according to the depth of the tumor position of the patient during accelerator treatment, and the size of the energy is adjusted by the charging pulse width: the width of a single pulse is wide in the high energy range, and the width of the single pulse is narrow in the low energy range, but the maximum repetition frequency is not changed.
The dosage rate of each energy gear of the accelerator determines the length of the irradiated time of the patient, and the irradiated time is short when the dosage rate is high. Under the influence of the bandwidth of the accelerating tube, the dosage rate of the accelerator at a low energy end is usually lower, only half of the dosage rate of a high energy level is even lower, under the maximum repetition frequency, the maximum absorption dosage rate generated by the high energy level of the accelerator can reach 500-600 cGy/Min, and the maximum absorption dosage rate generated by the low energy level is less than 200 cGy/Min. This means that the same dose takes more time at the low end, which severely affects the efficiency of the accelerator.
The dosage rate of the accelerator can be improved by improving the emission frequency of the beam, and the method does not need to adjust the filament current of the electron gun, and has the advantages of quick response, stable beam and the like. However, under the influence of a single signal source, once the highest energy level is determined, the maximum emission frequency of the low-energy level beam is also determined, and the purpose of increasing the dose rate cannot be achieved.
Disclosure of Invention
In view of this, the present invention provides a multi-signal source selection circuit of a modulator and a control method thereof, which can improve the dose rate at the low energy end of an accelerator.
The technical scheme for realizing the invention is as follows:
a multi-signal-source selection circuit of a modulator comprises an upper computer, a control CPU, a signal source selection circuit and a plurality of signal source storage circuits connected in parallel;
the number of the signal sources corresponds to the energy levels of the accelerators one by one, the number of the charging pulses of the signal sources corresponding to the high energy levels is large, the maximum repetition frequency is low, the number of the charging pulses of the signal sources corresponding to the low energy levels is small, and the maximum repetition frequency is high;
the upper computer is controlled to output an accelerator energy level signal, the control CPU generates a chip selection code according to the energy level signal and sends the chip selection code to the signal source selection circuit, and the signal source selection circuit controls a corresponding signal source to work according to the chip selection code.
A control method of a multi-signal-source selection circuit of a modulator is characterized in that when an accelerator needs to work at a high energy level, the signal-source selection circuit is controlled to select a signal source with relatively low maximum repetition frequency and a plurality of charging pulses in each repetition period; when the accelerator needs to work in a low energy level, the signal source selection circuit is controlled to select a signal source with relatively high maximum repetition frequency and few charging pulses in each repetition period.
A control method of a multi-signal source selection circuit of a modulator is characterized in that an upper computer is controlled to output an accelerator energy level signal and sends the accelerator energy level signal to a control CPU through the communication of a complete machine; the control CPU generates a synchronous clock and a chip selection code and sends the synchronous clock and the chip selection code to the signal source selection circuit, and the signal source selection circuit controls the output of a corresponding signal source according to the chip selection code and controls the repetition frequency of the selected signal source according to the synchronous clock; the accelerator high-energy level signal corresponds to a signal source with a large number of charging pulses and a low maximum repetition frequency, and the accelerator low-energy level signal corresponds to a signal source with a small number of charging pulses and a high maximum repetition frequency.
Has the advantages that:
the invention utilizes the difference of energy of the modulator flyback transformer needed when the accelerator is in high energy and low energy, designs and selects a plurality of signal sources to control the repetition frequency of the charging pulse of the flyback transformer, increases the times of beam emission in unit time by improving the repetition frequency of the charging pulse in low energy, thereby effectively compensating the dosage rate of the low energy end of the medical high-energy electronic linear accelerator, solving the problem that the capture rate is reduced due to the bandwidth limitation of an accelerating tube, thus the dosage rate of the whole medical accelerator is reduced, and improving the application range and the use efficiency of the medical accelerator.
Drawings
Fig. 1 is a schematic structural diagram of the circuit of the present invention.
FIG. 2 is a control flow chart of the present invention.
Detailed Description
The invention is described in detail below by way of example with reference to the accompanying drawings.
The invention provides a multi-signal-source selection circuit of a modulator, which comprises an upper computer, a control CPU, a signal source selection circuit and a plurality of signal source storage circuits connected in parallel as shown in figure 1;
the number of the signal sources corresponds to the energy levels of the accelerators one by one, and when the energy levels are high, the flyback transformer is required to store more energy, the number of charging pulses is large, and the maximum repetition frequency is relatively low; and in the low-energy gear, the flyback transformer is required to store less energy, and the maximum repetition frequency of the signal source with less charging pulses in each cycle of the repetition period is relatively higher. According to the invention, a plurality of signal sources are designed according to the beam energy required by the accelerator: a plurality of signal storages (signal storages 1-X) with a bus type structure are adopted, signal waveforms with different numbers of charging pulses (such as 2 pulses, 3 pulses, 4 pulses, 6 pulses and the like) are respectively solidified, and the minimum repetition period of each signal source is opposite to the minimum repetition period.
The upper computer is controlled to output an accelerator energy level signal, the control CPU generates a chip selection code according to the energy level signal and sends the chip selection code to the signal source selection circuit, and the signal source selection circuit controls a corresponding signal source to work according to the chip selection code.
A control method of a multi-signal-source selection circuit of a modulator is disclosed, as shown in figure 2, an upper computer is controlled to output an accelerator energy level signal, and the accelerator energy level signal is sent to a control CPU through the communication of the whole computer; the control CPU generates a synchronous clock and a chip selection code and sends the synchronous clock and the chip selection code to the signal source selection circuit, and the signal source selection circuit controls the output of a corresponding signal source according to the chip selection code and controls the repetition frequency of the selected signal source according to the synchronous clock; the accelerator high-energy level signal corresponds to a signal source with a large number of charging pulses and a low maximum repetition frequency, and the accelerator low-energy level signal corresponds to a signal source with a small number of charging pulses and a high maximum repetition frequency.
The control CPU generates a selection code according to the received accelerator energy level signal transmitted by the upper computer and transmits the selection code to the decoding circuit, and the decoding circuit generates a chip selection signal and controls the corresponding signal source to work by the addressing counter. In high energy level, if the energy stored in the flyback transformer is high, selecting a signal source with more charge pulses (such as 6 pulses) in each repetition period, wherein the maximum repetition frequency is relatively low (such as 5.8 mS); at low energy levels, where the flyback transformer is required to store low energy, a signal source with a relatively low number of charge pulses (e.g., 2 pulses) per cycle of the repetition period is selected, with a relatively high maximum repetition rate (e.g., 2 mS).
Therefore, the repetition period (such as 2mS) of the low energy level of the accelerator is shortened to be nearly one third of that of the high energy level (such as 5.8mS), which means that the emission frequency of the electron beam in unit time is increased to be nearly 3 times, the maximum dosage rate is theoretically increased to be nearly 3 times of that of a single signal source, and the maximum dosage rate reaches a value equivalent to the high energy level, so that the defect of low dosage rate at the low energy end of the medium and high energy medical electron linear accelerator is overcome.
In summary, the above description is only a preferred embodiment of the present invention, and is not intended to limit the scope of the present invention. Any modification, equivalent replacement, or improvement made within the spirit and principle of the present invention should be included in the protection scope of the present invention.
Claims (3)
1. A multi-signal-source selection circuit of a modulator is characterized by comprising an upper computer, a control CPU, a signal source selection circuit and a plurality of signal source storage circuits which are connected in parallel;
the number of the signal sources corresponds to the energy levels of the accelerators one by one, the number of the charging pulses of the signal sources corresponding to the high energy levels is large, the maximum repetition frequency is low, the number of the charging pulses of the signal sources corresponding to the low energy levels is small, and the maximum repetition frequency is high;
the upper computer is controlled to output an accelerator energy level signal, the control CPU generates a chip selection code according to the energy level signal and sends the chip selection code to the signal source selection circuit, and the signal source selection circuit controls a corresponding signal source to work according to the chip selection code.
2. A method of controlling the multiple signal source selection circuit of the modulator of claim 1, wherein when the accelerator is required to operate at a high energy level, the signal source selection circuit is controlled to select a signal source having a relatively low maximum repetition frequency and a large number of charge pulses per repetition period; when the accelerator needs to work in a low energy level, the signal source selection circuit is controlled to select a signal source with relatively high maximum repetition frequency and few charging pulses in each repetition period.
3. The method of claim 2, wherein the upper computer is controlled to output an accelerator power level signal, and the accelerator power level signal is sent to the control CPU through the whole computer communication; the control CPU generates a synchronous clock and a chip selection code and sends the synchronous clock and the chip selection code to the signal source selection circuit, and the signal source selection circuit controls the output of a corresponding signal source according to the chip selection code and controls the repetition frequency of the selected signal source according to the synchronous clock; the accelerator high-energy level signal corresponds to a signal source with a large number of charging pulses and a low maximum repetition frequency, and the accelerator low-energy level signal corresponds to a signal source with a small number of charging pulses and a high maximum repetition frequency.
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| Application Number | Priority Date | Filing Date | Title |
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| CN201911261242.5A CN111132440A (en) | 2019-12-10 | 2019-12-10 | Multi-signal-source selection circuit of modulator and control method thereof |
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| CN201911261242.5A CN111132440A (en) | 2019-12-10 | 2019-12-10 | Multi-signal-source selection circuit of modulator and control method thereof |
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| CN111132440A true CN111132440A (en) | 2020-05-08 |
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Citations (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JP2001326098A (en) * | 2000-05-16 | 2001-11-22 | Mitsubishi Electric Corp | Linear acceleration device, synchrotron acceleration device, particle beam therapy device, and control method of linear acceleration device |
| CN101163371A (en) * | 2006-10-13 | 2008-04-16 | 同方威视技术股份有限公司 | Stationary wave electron linear accelerator capable of fast response |
| CN102067449A (en) * | 2008-06-23 | 2011-05-18 | 斯堪的诺维亚系统公司 | Power switch grouping |
| US20150245463A1 (en) * | 2014-02-27 | 2015-08-27 | ETM Electromatic, Inc. | Linear accelerator system with stable interleaved and intermittent pulsing |
| CN106132058A (en) * | 2016-08-23 | 2016-11-16 | 苏州雷泰医疗科技有限公司 | A kind of homology multipotency accelerator and accelerator therapy device |
-
2019
- 2019-12-10 CN CN201911261242.5A patent/CN111132440A/en active Pending
Patent Citations (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JP2001326098A (en) * | 2000-05-16 | 2001-11-22 | Mitsubishi Electric Corp | Linear acceleration device, synchrotron acceleration device, particle beam therapy device, and control method of linear acceleration device |
| CN101163371A (en) * | 2006-10-13 | 2008-04-16 | 同方威视技术股份有限公司 | Stationary wave electron linear accelerator capable of fast response |
| CN102067449A (en) * | 2008-06-23 | 2011-05-18 | 斯堪的诺维亚系统公司 | Power switch grouping |
| US20150245463A1 (en) * | 2014-02-27 | 2015-08-27 | ETM Electromatic, Inc. | Linear accelerator system with stable interleaved and intermittent pulsing |
| CN106132058A (en) * | 2016-08-23 | 2016-11-16 | 苏州雷泰医疗科技有限公司 | A kind of homology multipotency accelerator and accelerator therapy device |
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Application publication date: 20200508 |