CN101573157B - Method and apparatus for stabilizing an energy source in a radiation delivery device - Google Patents
Method and apparatus for stabilizing an energy source in a radiation delivery device Download PDFInfo
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- CN101573157B CN101573157B CN2007800304611A CN200780030461A CN101573157B CN 101573157 B CN101573157 B CN 101573157B CN 2007800304611 A CN2007800304611 A CN 2007800304611A CN 200780030461 A CN200780030461 A CN 200780030461A CN 101573157 B CN101573157 B CN 101573157B
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Abstract
A radiation delivery device and method of stabilizing a microwave energy source. The device includes a microwave energy source, and a microwave utilization device coupled to the energy source. A non-reciprocal transmission device couples the source to the utilization device, the transmission device receiving an unutilized portion of the energy from the device. The transmission device conditions the unutilized energy and returns the conditioned energy to the source. The transmission device comprises a first component that operates to adjust a first property of the energy such that the adjustment does not affect any other properties of the energy. The returned conditioned energy functions to modify the frequency of the source such that the unutilized energy in the system is minimized, thereby stabilizing the frequency of the energy output by the source.
Description
The cross reference of related application
The application requires in the temporary patent application No.60/837 of submission on August 15th, 2006,901 priority, and the full content of this temporary patent application is incorporated into this by reference.
Technical field
The present invention relates to radiation delivery device, such as the radiotherapy in the treatment system.More specifically, the method and apparatus of operation frequency that the present invention relates to be used for the stability microwave energy source is with the output of optimization from particle accelerator in the system, and this source of microwave energy is such as magnetron oscillator.
Background technology
The Medical Instruments that is used for radiotherapy utilizes high-energy radiation to treat the tumprigenicity tissue.The position that must accurately control dosage mediating recipe amount with guarantee tumor receive abundant radiation be destroyed and minimize for around with the damage of contiguous non-tumprigenicity tissue.Intensity modulated radiation therapy (IMRT) utilizes many radiation to treat the patient, wherein can control the intensity and/or the energy of every radiation independently.Around the patient, ray is orientated from different angles, and combination is to provide the dosage pattern of expectation.Externally in the radiotherapy of source, utilize the outside radiation source of patient to treat inner tumor.Usually make the external source collimation only aim at the tumprigenicity position restrainting.Typically, radiation source is made up of radioisotopic high-energy X ray, electronics or gamma ray from the height collimation.The radiation source of carrying out this type radiotherapy can comprise the equipment that is known as magnetron, and this magnetron provides microwave power to linear accelerator (" LINAC ").
Summary of the invention
Treat the patient effectively for the linear accelerator that uses driven by magnetron utilizes IMRT, it is stable requiring from the dosage of LINAC output.Magnetron provides compact power source, and this compactness power source is suitable for using with the suitable rotation radiotherapy of size transmission (delivery) system, and the suitable rotation radiotherapy transmission system of this size is such as system to be described in detail below.Yet, the bigger frequency stability that linear accelerator needs Billy can obtain easily with magnetron usually to constant output.The mechanical vibration of magnetron can cause enough frequency change, change thereby produce than transmit continuously bigger output desired in the IMRT system.Therefore, the present invention is provided for the device of stabilized magnetron frequency with the constant output of acquisition expectation.In fact, the objective of the invention is to adopt source device, and because the load (for example LINAC) of this device coupled to height resonance caused this device-restrictive in narrower bandwidth, to operate such as magnetron with extensive.For the unstability in the anti-locking system, the output frequency of magnetron should mate with the operation frequency of LINAC.
In one embodiment, the invention provides a kind of radiation delivery device.This equipment comprises: source of microwave energy, such as magnetron; And the microwave that is coupled to this energy source utilizes equipment.Non-each other (non-reciprocal) transporter is coupled to the equipment that utilizes with this source, and receive from this utilize equipment energy do not utilize part.Transfer equipment adjustment (condition) at least a portion is not utilized energy, and adjusted energy is turned back to energy source.Transfer equipment comprises first parts, and this first operation of components wherein makes this adjusting not influence any other attribute of energy to regulate first attribute of energy.The adjusted effect of returning that can measure the frequency of revising energy source is not so that utilize energy minimization in radiation delivery device.
In this case, utilizing equipment, is particle accelerator in the embodiment shown, has the narrow bandwidth of operation of inherent bandwidth of operation in the specific energy generation source.This difference is caused by following: need magnetron to collect from the electronics of the occupied most of phase space of its thermal diffusion of high current electron beam, with the effective conversion that realizes that beam energy vibrates to radio frequency (RF).The narrow bandwidth of accelerator is the result of following target: obtain maximized internal electric field, to produce the maximum radiation energy in the shortest physical length for given power input.Method according to stabilisation systems of the present invention can be applied to any form based on RF-accelerated particle/photon (modality).
To pass through non-mutual transfer equipment by the microwave energy that magnetron produces, and such as waveguide, arrive linear accelerator, this linear accelerator utilizes this energy to produce high energy electron and/or X ray.Use traditional automatic frequency control feedback loop with the output frequency mechanical tuning of magnetron resonant operational frequency, to follow the tracks of thermal change to LINAC.When the resonant operational frequency from the frequency of the energy of magnetron and LINAC did not match, microwave energy was reflected from LINAC.To waveguide elements, these waveguide elements are controlled the amplitude and the phase place of reflected energy to the energy route of reflection dividually through circulator (circulator).The energy of amplitude and phase controlled turns back to magnetron then, and at this magnetron place, controlled energy applies backlash.When the amplitude of using reflected energy with ad hoc fashion and phase place, pulling effect and magnetron frequency depart from the little skew opposition (in opposition to) of the resonant frequency of LINAC.This effect takes place in part microsecond, with several milliseconds of response times formation contrasts of mechanical tuning system.
The present invention also provides the method for stability microwave energy source, and this source is coupled to microwave and utilizes equipment.This method comprises: non-mutual transfer equipment is coupled to this source, and will be directed to the equipment that utilizes through transfer equipment from the energy in source.To adjusting from least a portion of utilizing the energy that equipment returns, wherein, adjustment comprises first characteristic of revising energy and any other characteristic that does not influence this energy.This portion of energy after the processing is returned energy source, and plays the frequency output in stable energy source.
Through considering detailed description and drawings, it is obvious that other aspects of the present invention will become.
Description of drawings
Fig. 1 is the perspective view of radiotherapy in the treatment system.
Fig. 2 is the perspective view that can be used in the multi-diaphragm collimator in the radiotherapy in the treatment shown in Figure 1 system.
Fig. 3 is the front view that is used for the magnetron that the system with Fig. 1 uses.
Fig. 4 is the sketch map that is used for the RF subsystem that the system with Fig. 1 uses.
Fig. 5 is the block diagram of Radiation Module of system that is schematically illustrated as Fig. 1 of circuit.
Fig. 6 is the block diagram that is schematically illustrated as the alternate embodiment of the present invention of utilizing 3 port circulator of circuit.
Fig. 7 is frequency and power output that Fig. 4 system is shown for gram (Rieke) figure in load impedance dependent.
Fig. 8 is the input impedance of synergetic LINAC in the complex impedance plane and from the diagram of the frequency line of the magnetron Rieke diagram of Fig. 7.
Fig. 9 is how the adjusting of magnetron moves the Rieke diagram frequency line in the complex impedance plane a diagram.
Figure 10 is that the impedance roller profile (contour) of LINAC is how along with the size of the reflection coefficient at port 3 places of 4 port circulator that are used for Fig. 4 system and the diagram that changes.
Figure 11 is that the impedance roller profile of LINAC is how along with the phase place of the unit reflection coefficient at port 4 places of 4 port circulator and the diagram that changes.
Figure 12 is the diagram of restriction of selection of part (fractional) reflection coefficient at the upper limit that can be returned the reflection power of magnetron port 3 places that how to receive 4 port circulator.
The specific embodiment
Before illustrated in detail any embodiment of the present invention, should understand application of the present invention be not limited to illustrate in the following description or below the layout of CONSTRUCTED SPECIFICATION shown in the drawings and parts.The present invention can be embodied as other embodiment, and can realize in many ways or carry out.And, should be understood that word used herein and term for illustrative purposes, and should not think restriction.Here use " comprising ", " comprising " or " having " and variant intention thereof to contain item and equivalence and the other item of after this listing.Only if point out in addition or limit, term " installation ", " connection ", " support " and " coupling " and variant thereof use with broad sense, and contain direct with indirect installation, be connected, support and coupling.Further, " connection " and " coupling " are not limited to being connected or coupling of physics or machinery.
Though when accompanying drawing is described, carried out such as upper and lower, downward, upwards, backward, bottom, forward and backward etc. direction reference, these are with reference to making with respect to accompanying drawing (like normal findings) just to convenient.These directions are not intended to letter or limit the present invention by any way.In addition, using the term such as " first ", " second " and " the 3rd " here is for illustration purpose, and is not intended to indicate or hint relative importance or meaning.
In addition, should be understood that embodiments of the invention comprise for discuss purpose can be illustrated or be described as just as most of parts only with hard-wired hardware, software and electronic unit or module.Yet those skilled in the art will recognize that based on the detailed description of reading here at least one embodiment, the aspect based on electronics of the present invention can realize with software.So, should be noted that and can use a plurality of equipment based on hardware and software, and a plurality of various structure parts, realize the present invention.In addition, and as in subsequent paragraph, describe specific mechanical configuration intention illustration embodiments of the invention shown in the accompanying drawing, and other optional mechanical arrangements also are fine.
Fig. 1 illustrates the radiotherapy in the treatment system 10 that radiotherapy can be provided patient 14.It as follows is an example of the radiation delivery device that can operate according to the present invention with the radiotherapy in the treatment system of describing.Radiotherapy in the treatment can comprise the treatment of radiotherapy, short distance radiotherapy, electron beam therapy, proton therapeutic, neutron therapy or particle therapy or other types based on photon.Radiotherapy in the treatment system 10 comprises frame 18.Frame 18 can be supported radiation delivery module 22, and this radiation delivery module 22 can comprise can operate the radiation source 24 and linear accelerator 26 that produces radiant flux 30.Though frame 18 is annular frameworks shown in the figure, promptly it extends through 360 ° of complete arcs to create complete ring or circle, also can use the mounting arrangements of other types.For example, can use C type, part annular framework or mechanical hand.Also can use and can radiation delivery module 22 be positioned at respect to a plurality of rotations of patient 14 and/or any other framework (framework) of axial location.In addition, radiation source 24 can be advanced along the path of the shape of not following frame 18.For example, though shown in frame 18 be substantially circular, radiation source 24 also can be advanced along non-circular path.Radiation source 24 can comprise that the source takes place energy, and such as magnetron 32 (shown in Figure 3), this magnetron 32 produces the energy (shown in Figure 4) that is delivered to LINAC 26 to be passed.To discuss magnetron 32 and LINAC 26 below in more detail.
Modulating equipment 34 can comprise collimating apparatus 42, and is as shown in Figure 2.This collimating apparatus 42 comprises a cover jaw spare 46, and this cover jaw spare 46 limits the also size of adjustment aperture 50, and radiant flux 30 can pass through this aperture 50.Jaw spare 46 comprises upper jaw 54 and lower jaw 58.Upper jaw 54 and lower jaw 58 removable sizes with adjustment aperture 50.
In one embodiment; As shown in Figure 2, modulating equipment 34 can comprise multi-diaphragm collimator 62, and this multi-diaphragm collimator 62 comprises a plurality of staggered (interlaced) leaves 66; These a plurality of staggered leaves 66 can be operated from a position and move to another position, so that intensity modulated to be provided.Be also noted that the position that can leaf 66 be moved to any place between minimum and the maximum open position.Before the zone 38 that radiant flux 30 arrives on the patient 14, intensity, the size and dimension of these a plurality of staggered leaf 66 radiation beam 30.Leaf 66 controls independently each leaf 66 through actuator 70, so that can open and close with permission fast or block radiating passing through such as motor or air cock.Can control actuator 70 through computer 74 and/or controller.
Radiotherapy in the treatment system 10 can also comprise detector 78, and for example kilovolt level or megavolt level detector can operate receiver radiation bundle 30, and be as shown in Figure 1.LINAC 26 also can operate as CT computer tomography (CT) system to produce patient 14 CT image with detector 78.Zone 38 radiation beams 30 of LINAC 26 in the patient 14.Zone 38 absorbs some radiation.Detector 78 detects or measures the amount of radiation that is absorbed by zone 38.Patient 14 rotates and towards patient's 14 emitted radiations, detector 78 is collected from the absorption data of different angles along with LINAC 26 centers on.The absorption data of collecting is sent to computer 74 to handle this absorption data and to produce the image of patient's body tissue and organ.Image also can illustrate bone, soft tissue and blood vessel.
Radiotherapy in the treatment system 10 also can comprise patient's supporter, and such as therapeutic bed 82 (shown in Figure 1), it supports patient 14.Therapeutic bed 82 moves along at least one axle 84 on x, y or the z direction.In other embodiments of the invention, patient's supporter can be any equipment that is suitable for supporting any part of patient body.Patient's supporter is not limited to must support the whole health of patient.System 10 can also comprise drive system 86, and this drive system 86 can be operated the position of handling therapeutic bed 82.Can come control-driven system 86 through computer 74.
Magnetron 32 shown in Figure 3 produces the microwave radiation that is used to be delivered to LINAC 26.On top level (level), magnetron adopts DC power and is converted into RF power.Power transfer is mutual (reciprocal), and just, magnetron is imported with the power that mode equal and opposite (opposite) is coupled to magnetron with power output.Such magnetron that can use according to the present invention is the model MG-6493 that is provided by Britain e2v Technologies company.Magnetron 32 is high-power microwave oscillators, wherein, in a series of resonator cavitys 88, will be RF energy from the power conversion of the accelerated electron of cylindrical cathode 84 emission.Resonator cavity 88 is limited on the wing (vane) 92.Negative electrode 84 is centered on by concentric anode 104.Magnetron 32 is dipped in the magnetic field that the axle of negative electrode 84 applies.
Along with negative electrode 84 is heated, produce electronics, under the effect of the radial electric field between negative electrode 84 and the anode 104, these electronics are radially outward advanced and are attracted to anode 104.This magnetic field is the serpentine track between negative electrode 88 and the anode 104 with electronic deflection, and chamber 88 internal inductions go out the RF electric current.This causes storing the energy in the chamber 88 with the resonant frequency in chamber 88.Thereby convert the kinetic energy of electronics into the RF energy, in the embodiment shown, about 60% electronic kinetic energy is converted into microwave energy.
The magnetron 32 of illustrated embodiment can be with multiple frequency mode vibration, and this multiple frequency mode comprises the π pattern.In order to reduce probability, through the wing 92 with 108 connection magnetrons 32 with the mode oscillation except that the π pattern.Connect the alternately wing 92 and ignore (pass over) adjacent foil 92 of 180 ° of out-phase when being in the π mode frequency with 108 with equal potential energy.Via coupling ring 120, be coupled out chamber 88 of RF power is arrived the circular waveguide parts.This coupling is mutual, and can the coupling of RF power be got back in the magnetron 32 with the efficient identical with magnetron 32 outputs.Close coupling increases output and efficient, but the sensitivity that also increases time jitter and change for load mismatch.
Though should be understood that in the above to have gone through a specific magnetron configuration about Fig. 3, other magnetron configurations also are fine, and still fall within the scope of the invention.The basic operation of magnetron and parts are known to those skilled in the art, and it will be understood by those skilled in the art that the variation that can make the magnetron configuration of discussing above comparing and still fall within the scope of the invention.
Fig. 4 illustrates the LINAC 26 that uses in the system 10.LINAC 26 comprises three basic elements of character: electron gun 128, accelerator 132 and target 136.128 power supplies of 140 pairs of electron guns of infusion appliance, and be directed against each pulse injection current pulse from the RF power of magnetron 32.Electron gun 128 comprises the negative electrode that is heated with the generation electronics.The electronics that is produced by electron gun 128 is attracted to the rifle anode, and is injected in the accelerator 132 with about 13KV in the embodiment shown.
Then, injected electrons is grouped into bundle, quickens so that electron beam can be made the as a whole device 132 that is accelerated.Accelerator comprises a plurality of accelerating cavities, and each accelerating cavity comprises applied field, and this applied field quickens electronics when electronics is through these chambeies.Coupled resonator cavity forms the multi-cavity accelerating structure.Come the quantity (quantity that promptly has the operating condition of particular resonant frequency and characteristic field pattern) of deterministic model through the quantity (being the quantity of resonator) in chamber.The accelerator 132 that utilizes in the embodiment shown is standing wave accelerators, and wherein, electromagnetic wave forms standing wave in the reflection of place, end and the bounce-back back and forth in chamber.Yet, should understand the accelerator that in system 10, also can use other types and also still fall within the scope of the invention.
Then, facing to target 136 bombardment accelerated electrons.Bombard and cause the bremsstrahlung effect in the target 136.136 pairs of accelerated electrons of target slow down, in the emission that X ray takes place to cause when electronics slows down.The energy of the X ray of emission changes along with the energy of bombardment electronics.For example, when increasing the energy of bombardment electronics, the X ray of emission becomes and energy is more arranged and squints to higher frequency.Target 136 is formed by high atomic number metal, and like tungsten, it can bear the hyperpyrexia that is produced by electron bombard.In some cases, LINAC uses cooling mechanism to assist cooled target 136.
Though described the customized configuration of LINAC 26 in the above, it will be understood by those skilled in the art that other LINAC 26 configurations also are fine, and still fall within the scope of the invention.Above-mentioned LINAC 26 configurations are examples of LINAC 26 embodiment using with the present invention.Basic operation and the parts of LINAC are known in this area, and it will be appreciated by those skilled in the art that other LINAC configurations also are fine.
With discussed in detail, magnetron 32 operatively is coupled to together with LINAC 26 as follows, so that magnetron 32 is worked in system 10 with LINAC 26 together.Keep the operation frequency of magnetron 32 mechanical tunings through feedback system, also be known as automatic frequency control 156 (AFC) to LINAC 26.AFC 156 drives electronic plug (motorized plunger) (not shown), in this electronic plug disturbance (perturb) magnetron cavity 88 one.This plug is as magnetron tuner 158.In order to minimize the frequency deviation when magnetron 32 centers on horizontal rotational shaft, this should be parallel to the axle of tuner 158.AFC 156 is as mechanical tuner, and is used for coming tuned frequency through following behavior: check behavior average of each RF pulse, and regulate tuner 158 so that minimize from the power of LINAC 26 reflections.Thereby AFC 156 effects can not be proofreaied and correct each RF pulse inadequately soon.Therefore, if magnetron 32 output frequencies are such as because mechanical vibration cause quick variation, then each pulse can replace high and low so that pulse on average still in operating parameter, but magnetron 32 is still operated outside the output frequency of expecting.
Figure 4 and 5 are the block diagrams that the radiation delivery module 22 of system 10 are depicted as circuit.Magnetron 32 receives the power from manipulator 150, and it produces the very short pulse of high voltage and electric current.Magnetron 32 arrives microwave transfer in LINAC 26 through 4 port circulator 160.The mutual plumbing of these 4 port circulator, 160 right and wrong, its power that uniaxially guiding applies between a series of ports.In essence, 4 port circulator 160 are coupled to LINAC 26 with magnetron 32, and as isolator.4 port circulator 160 allow from the amplitude of the power of LINAC 26 reflected backs and the independent regulation of phase place.It will be understood by those skilled in the art that amplitude and phase place only are two characteristics of the energy in the module that can control.In other embodiments, also can regulating frequency and wavelength.
The power of reflection is caused by the frequency instability in the circuit.Previous system uses 3 port circulator, wherein, uses the single adjusting that influences amplitude and phase place.Allow more accurately and easily to regulate this two compositions separating of phase place and amplitude adjusted among the present invention, causes system to control more accurately and the better predictability of the operation of magnetron 32.Magnitude of separation control also allows the simple restriction for the reflection power that arrives magnetron 32, does not exceed the maximum that magnetron 32 can be allowed to guarantee reflection power.
Use circulator 160 to arrive in the high power load 164, from the power of LINAC 26 reflections from magnetron 32 call away tos to avoid unstability and possibly damage for magnetron 32.As shown in Figure 4, this circuit comprises part (fractionally) reflecting element (promptly reflecting transducer 168) that is connected in series with high power load 164.Reflecting element (just phase-shifter 172) that phase place is adjustable, complete is on the 4th circulator port between partial reflection element 168 and the magnetron 32.
Through utilizing 4 port circulator 160 and being attached to the parts on it, can separate and the amplitude and the phase place of accommodation reflex power (energy) independently.When magnetron 32 was inaccurately operated on LINAC 26 resonant frequencies, reflection power in a small amount arrived magnetron 32.The behavior of reflection power is a frequency of revising magnetron 32 with the mode of eliminating reflection power, creates feedback control loop.Tuning correction takes place in part microsecond that each pulse begins, so in fact almost there is not reflection power to arrive magnetron 32.Therefore, system 10 by electronic tuning to solve the variation of each RF pulse.
Though shown in use 4 port circulator in the embodiment of the invention, it should be understood that, can use the equipment of other types replace shown in the circulator.For example, as shown in Figure 6, can use 3 port circulator 180 with isolating phase place and amplitude control.Shown in 3 port circulator 180, phase-shifter 184, partial reflection element 188 and high power load 192 are arranged as the 3rd port that is connected in series to 3 port circulator 180.Will be from power transmission process phase-shifter 184 and arrival reflecting element 188, the antireflection part power here of LINAC 26 reflections.With most of power, under the certain situation about 98% power, transmit the load 192 that arrives dissipated power through reflecting element 188.The power transmission of reflection is returned through phase-shifter 184, and dephased reflection power is delivered to magnetron 32.Power cycle of 3 port circulator 180 (circulating) and port isolation function are extended (to carry out phase shift) and control phase independently with the electrical length of 4 port circulator, the 160 identical-waveguides of top discussion basically, though utilize 4 port circulator 160 to have other benefits as coupling mechanism.In addition, can use any other configuration of the non-mutual plumbing with unidirectional power transmission according to the present invention, the independent control of the phase place of the reflection power in its permission system and amplitude.For example, can use 5 port circulator, also can use port and realize the top circulator that function is discussed with any other quantity.
In the embodiment shown, so that the load impedance curve is perpendicular to the phase place of equifrequent curve in the Rieke diagram (see figure 7) of magnetron 32, the reflection power with 2% is applied to magnetron 32, and draws magnetron 32 output frequencies towards the resonant frequency of LINAC 26.When suitable tuning circuit, actual reflection be near 0 2%.It is peaked 4% that actual reflection power is selected as that the designing institute that is not more than magnetron 32 allows, and minimum reflected power is greater than 0.
Fig. 8 illustrates: the LINAC impedance in the complex plane, the resonance center is at f
OlThe place, and frequency increases in the clockwise direction; And the equifrequent contour line in the complex impedance plane, frequency as shown in increase and have a magnetron mid frequency f
OmWork as f
Om=f
OlThe time should obtain stable operation.
Fig. 9 is how the adjusting of magnetron 32 moves the frequency line of Rieke diagram in the complex impedance plane a diagram.Magnetron tuner 158 moves equifrequent family of curves quadrature ground in impedance plane to its direction.This is the purpose of AFC 156, and is first customized parameter about impedance and frequency relation.Say that fundamentally magnetron 32 need be tuning in 1/2 power bandwidth of LINAC 26, it is that the LINAC impedance becomes and the tangent point of equifrequent contour line (is seen among Fig. 8
*---
*).
Figure 10 be LINAC 26 is shown the impedance roller profile how along with the size of the reflection coefficient of the 3rd port of 4 port circulator 160 and the diagram that changes.The size of the LINAC impedance that the variation change magnetron 32 of the volume reflection that before high power load 164, increases is seen is as illustrated in Figure 10.This is second customized parameter about impedance and frequency relation.
Figure 11 be LINAC 26 is shown the impedance roller profile how along with the phase place of the unit reflection coefficient of the 4th port of 4 port circulator 160 and the diagram that changes.The phase place of 100% reflection of change on common low power load port (i.e. the 4th port) is rotated in the impedance curve (seeing Figure 11) in the complex impedance plane.This is the 3rd customized parameter about impedance and frequency relation.
At the λ that inserts with high power load 164 with being connected in series
gControl second customized parameter through the impedance step in/4 resonant transducer 168.The voltage standing wave ratio of such transducer (VSWR) is:
VSWR＝[Z
0/Z
1]
2。
With TE
10Generally being expressed as of the impedance of the rectangular waveguide of pattern operation:
And wherein, the waveguide wavelength that vacuum is propagated does
Because λ
gDo not rely on duct height " b ", the part that reduces height will have and the identical frequency dependence of main waveguide of amounting to the nominal impedance place:
Z
1＝(b
1/b
0)Z
0
Thus, the VSWR in the transducer is:
VSWR＝(b
0/b
1)
2。
And, voltage reflection coefficient Γ=(VSWR-1)/(VSWR+1), and reflection coefficient of power is Γ
2
With reference to Figure 12, usually the LINAC input impedance from a side of resonance to opposite side is rendered as the tangent circle of unit circle with boundary (bounding) Smith chart.Figure 12 is the diagram of constraint of the partial reflection coefficient selection of the upper limit that can turn back to the reflection power of magnetron 32 the 3rd port that how to receive 4 port circulator 160.Impedance is near initial point during resonance, and is shown in figure 12.Calibrate (scale) this impedance profile diagram through reflection coefficient Γ, be restricted to Γ so that turn back to the upper limit of the power of magnetron 32
2For magnetron 32, the set upper limit of VSWR is 1.5, and it is corresponding to 4% power reflection.When operating in 1/2 power bandwidth at LINAC 26, in fact reflect this power, and when resonance, this reflection is arranged by the other defect in the RF chain (imperfection) less than 1/2.
Through controlling the 3rd customized parameter in the slip short circuit (sliding short) 172 (being phase-shifter) of low power load place installation usually.
Can change the frequency of magnetron output according to the phase place of quantity of power that reflexes to magnetron and reflection power, and the unstability in magnetron 32 outputs can be caused by unsteered power reflection from LINAC 26.Use the circulator with respect to the reflection power that produces by LINAC magnetron and LINAC to be kept apart basically.Yet antihunt means recited above are used to stable fluctuation with complete different reasons, such as mechanical vibration, to guarantee the control of magnetron output.In order to use the power source of magnetron 32 as LINAC 26, the frequency of the output that needs restraint.In a preferred embodiment, known, in check quantity of power is reflected back toward magnetron 32, to obtain the suitable control of magnetron 32 outputs.
Should understand; Though top description is illustrated the present invention and its use in the radiotherapy in the treatment system relatively, the method and apparatus that is used for the stability microwave energy source described here can be used in any other application of the stability of the energy output that needs source of microwave energy.For example, the present invention can be applied to some microwave radar application.It will be understood by those skilled in the art that the specific radiotherapy example that goes through only is one of the present invention and possibly uses here, and other use and also to be fine and still to fall within the scope of the invention.
Various characteristic of the present invention can find in appended claim.
Claims (22)
1. radiation delivery device comprises:
Magnetron;
Linear accelerator is coupled to said magnetron; And
The circulator; Said circulator is coupled to said linear accelerator with said magnetron, and said circulator receives the part of not utilizing from the energy of said linear accelerator, adjusts said at least a portion of not utilizing energy; And adjusted energy turned back to said magnetron; Said circulator comprises the partial reflection element, and this partial reflection element operation wherein makes said adjusting not influence any other attribute of said energy to regulate first attribute of said energy;
Wherein, the said adjusted effect of returning that can measure the frequency of revising said magnetron makes the energy minimization that do not utilize in system,
Wherein, said first attribute of the said energy of regulating through said circulator comprises in phase place, amplitude, wavelength and the frequency,
Wherein, said energy said utilizes the mismatch between the incoming frequency of output frequency that part is illustrated in said magnetron and said linear accelerator.
2. equipment according to claim 1, wherein, said circulator is 4 port circulator.
3. equipment according to claim 1, wherein, said circulator also comprises second parts, this second operation of components is regulated second attribute of said energy with any other attribute that is independent of said energy.
4. equipment according to claim 3, wherein, said circulator's said second parts are phase-shifters.
5. equipment according to claim 1 also comprises the mechanical tuner that said magnetron is operated.
6. equipment according to claim 5, wherein, said mechanical tuner is striden the said frequency of not utilizing energy of average adjusted of each energy pulse.
7. equipment according to claim 1, wherein, said circulator can adjust each energy pulse, makes the frequency of said circulator based on the tuning said magnetron in Pulse by Pulse ground.
8. equipment according to claim 1, wherein, said circulator can regulate said phase place and the amplitude of not utilizing power that turns back to said magnetron dividually.
9. equipment according to claim 1; Wherein, said linear accelerator has the frequency stability higher than said magnetron, and wherein; Adjust the said energy that do not utilize and make that the said frequency output of said magnetron is stable, in the frequency bandwidth of said linear accelerator, to operate.
10. radiation delivery device comprises:
Magnetron;
Linear accelerator, this linear accelerator are confined in the frequency bandwidth than the more accurately control that is provided by said magnetron and operate, and make it possible to be used to the only part from the energy of said magnetron; And
The circulator receives the part of not utilizing from the energy of said linear accelerator reflection, and before adjusted energy is turned back to said magnetron, does not utilize energy adjustment to said;
Wherein, said circulator separates and regulates independently at least two different attributes of said energy.
11. equipment according to claim 10, wherein, said circulator is 4 port circulator.
12. equipment according to claim 10, wherein, said adjusted energy in said magnetron so that in said radiation delivery device, do not utilize energy minimization.
13. equipment according to claim 10, wherein, said circulator also comprises phase-shifter, and this phase-shifter can be operated the phase place of regulating the energy that turns back to said magnetron.
14. equipment according to claim 10, wherein, said circulator also comprises reflecting element, and said reflecting element can be operated the amplitude of regulating the energy that turns back to said magnetron.
15. equipment according to claim 10, wherein, said circulator can operate and regulate the one or more of following energy feature independently: phase place, amplitude, wavelength and frequency.
16. equipment according to claim 10, wherein, phase place and amplitude that said circulator separates and regulates energy independently.
17. equipment according to claim 10, wherein, said circulator can adjust each energy pulse, makes said circulator based on the tuning said energy in Pulse by Pulse ground.
18. the method for a stabilized magnetron, said magnetron is coupled to linear accelerator, and this linear accelerator is operated in than the narrow frequency bandwidth of said magnetron, and said method comprises:
The circulator is coupled to said magnetron;
To be directed to said linear accelerator through said circulator from the energy of said magnetron;
At least a portion of the energy that adjustment is returned from said linear accelerator, said set-up procedure comprises first characteristic of revising said energy and any other characteristic that does not influence said energy; And
The adjusted part of said energy is turned back to said magnetron;
Wherein, the said adjusted effect that can measure the frequency output of stablizing said magnetron,
Wherein, the said returning part of said energy is illustrated in the frequency mismatch between said magnetron and the said linear accelerator.
19. method according to claim 18, wherein, with the adjusted part of said energy turn back to frequency that said magnetron is used to draw said magnetron with the frequency alignment of said linear accelerator.
20. method according to claim 18, wherein, the said part of adjusting said energy comprises transmits said energy process phase-shifter to revise the energy phase place.
21. method according to claim 18, wherein, the said part of adjusting said energy comprises transmits said energy process reflecting element to revise the ability discharge amplitude.
22. method according to claim 18, wherein, at least a portion of adjusting said energy comprises adjustment each pulse by the energy of said magnetron output, with the frequency based on the said energy of Pulse by Pulse ground control.
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| US83790106P | 2006-08-15 | 2006-08-15 | |
| US60/837,901 | 2006-08-15 | ||
| US11/838,790 US20080043910A1 (en) | 2006-08-15 | 2007-08-14 | Method and apparatus for stabilizing an energy source in a radiation delivery device |
| US11/838,790 | 2007-08-14 | ||
| PCT/US2007/075994 WO2008022188A1 (en) | 2006-08-15 | 2007-08-15 | Method and apparatus for stabilizing an energy source in a radiation delivery device |
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| JP5490651B2 (en) * | 2010-09-01 | 2014-05-14 | 住友重機械工業株式会社 | Neutron beam irradiation system |
| CN103124302A (en) * | 2012-06-08 | 2013-05-29 | 王洪洋 | Technology for reusing radio frequency reflected signals of mobile phone |
| CN103908277B (en) | 2012-12-31 | 2017-03-08 | 清华大学 | CT Apparatus for () and method therefor |
| CN103908281B (en) * | 2012-12-31 | 2016-12-28 | 清华大学 | CT Apparatus for () and method therefor |
| CN103913473B (en) * | 2012-12-31 | 2017-02-08 | 清华大学 | CT (computed tomography) equipment and usage method thereof |
| JP6449127B2 (en) * | 2014-10-27 | 2019-01-09 | 住友重機械工業株式会社 | Neutron capture therapy treatment table and neutron capture therapy system |
| CN109922592B (en) * | 2017-12-13 | 2020-05-19 | 中国科学院大连化学物理研究所 | Electronic energy threshold online monitoring radiation safety interlocking system device and method |
| IL278033B1 (en) * | 2018-04-25 | 2024-01-01 | Adam S A | A proton linear accelerator system for irradiating tissue with two or more rf sources |
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| US5791599A (en) * | 1995-07-18 | 1998-08-11 | Blackburn; Ronald F. | System for increasing the aerodynamic and hydrodynamic efficiency of a vehicle in motion |
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| CN87103332A (en) * | 1986-05-02 | 1987-11-11 | 瓦里安公司 | Compressional wave hyperthermia treatment method and apparatus |
| US5103103A (en) * | 1990-07-19 | 1992-04-07 | Westinghouse Electric Corp. | Microwave shield |
| US5791599A (en) * | 1995-07-18 | 1998-08-11 | Blackburn; Ronald F. | System for increasing the aerodynamic and hydrodynamic efficiency of a vehicle in motion |
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