CN105137375A - RF channel calibration method and device, SAR measurement method, and magnetic resonance system - Google Patents
RF channel calibration method and device, SAR measurement method, and magnetic resonance system Download PDFInfo
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- CN105137375A CN105137375A CN201410231484.0A CN201410231484A CN105137375A CN 105137375 A CN105137375 A CN 105137375A CN 201410231484 A CN201410231484 A CN 201410231484A CN 105137375 A CN105137375 A CN 105137375A
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Abstract
The invention provides an RF channel calibration method and a device, an SAR measurement method, and a magnetic resonance system. The RF channel calibration method comprises a step of determining the expected power of a RF channel based on the power of a calibration signal, wherein the power of the calibration signal is determined by the preset power outputted by the RF signal emitting circuit of the magnetic resonance system, a step of determining the calibration parameter of the RF signal according to the expected power of the RF channel and the output power of the RF signal, wherein the RF signal is obtained after the coupling of a directed coupler in the RF channel, and a step of carrying out real-time calibration on the output power of the RF signal based on the calibration parameter of RF signal in a magnetic resonance system collection mode. The RF channel of the magnetic resonance system can be calibrated in real time, the method is easy and simple, and more accurate RF power can be obtained. An SAR value is calculated based on the calibrated power of the RF signal, the accuracy of the SAR value measurement is effectively ensured, and the credibility of SAR value monitoring is increased.
Description
Technical field
The present invention relates to magnetic resonance system technical field, particularly relate to a kind of calibration steps and device, a kind of SAR measuring method and a kind of magnetic resonance system of radio-frequency channel of magnetic resonance system.
Background technology
Magnetic resonance imaging (MRI, MagneticResonanceImaging) is the most frequently used medical imaging technology in radiology, the inner structure of the person and function being carried out to detailed visualizations.During magnetic resonance system imaging, patient can absorb the radio frequency (RF that MR imaging apparatus is launched, RadioFrequency) part for energy, this may cause patient body tissue to generate heat and other spinoff, such as, change eyesight, hearing and nervous function.
In magnetic resonance system, because the measurement of energy Ratios absorptivity (SAR, the SpecificAbsorptionRate) value in system relates to patient safety, very important, so need to monitor SAR value.Described SAR for unit, is the RF power of per unit mass tissue resorption with every kilogram watt (W/Kg).SAR is one of most important parameters relevant to thermal effect, act as the index of magnetic resonance system safety.Usually, the measurement of SAR value is according to the power calculation of some radiofrequency signals of drawing for monitoring RF power, therefore, Accurate Calibration or the power of measuring described radiofrequency signal will can directly affect the accurate calculating of SAR value, and then have influence on described magnetic resonance system and whether can cause to patient dangerous assessment of burning.
The rf monitoring technology that more current magnetic resonance system adopts is for design separately one piece of Acquisition Circuit for radiofrequency signal, this Acquisition Circuit is as subassembly, and before MR imaging apparatus is dispatched from the factory, carrying out radio-frequency power to it, to correct with the dummy gain ensureing its each radio frequency monitoring Signal reception passage when dispatching from the factory be consistent.
Can by realizing the detection of the power of Acquisition Circuit to the monitoring of described radiofrequency signal after dispatching from the factory.The field of what the application of existing power detection techniques was the most general is surveying instrument, such as power meter, frequency spectrograph, and signal source analyzer.Described power detection techniques is applied in the monitoring of the radiofrequency signal of magnetic resonance.For the monitoring of the security monitoring radiofrequency signal of magnetic resonance, current generally tendency adopts the stronger rf monitoring unit of packaging effects, namely ensure that the rf monitoring unit of the system that is integrated into is through after calibration, and each channel power and phase place is highly consistent.
Although this way is convenient to the division of each component function in magnetic resonance system, make each parts more independent, be convenient to the management of parts and the investigation of problem, but careful temperature compensation will be carried out in its inside, and consider the aging performance the caused drift in time of parts, also need genuine of taking back regular for the described rf monitoring unit carrying Acquisition Circuit to recalibrate.
Prior art needs to calibrate described rf monitoring unit when dispatching from the factory, and still need regularly to be brought back to genuine after dispatching from the factory and recalibrate, cannot calibrate by radio frequency signal in real time, calibration steps is complicated.
Summary of the invention
The problem that the present invention solves to be calibrated by radio frequency signal in real time, and the problem that calibration is complicated.
For solving the problem, technical solution of the present invention provides a kind of calibration steps of radio-frequency channel of magnetic resonance system, comprising:
Power based on calibrating signal determines the expectation power of described radio-frequency channel, and the power of described calibrating signal is that the predetermined power exported by the emission of radio frequency signals circuit of described magnetic resonance system is determined;
Determined the calibration parameter of described radiofrequency signal by the expectation power of described radio-frequency channel and the output power of radiofrequency signal, described radiofrequency signal is the signal obtained after directional coupler coupling in described radio-frequency channel;
Under magnetic resonance system drainage pattern, the calibration parameter based on described radiofrequency signal carries out real time calibration to the output power of described radiofrequency signal.
Technical solution of the present invention also provides a kind of SAR measuring method, comprising:
Adopt the calibration steps of the radio-frequency channel of magnetic resonance system as above, obtain the power after the calibration of described radiofrequency signal;
Based on SAR value described in the power calculation after described radiofrequency signal calibration.
Technical solution of the present invention also provides a kind of calibrating installation of radio-frequency channel of magnetic resonance system, comprising: emission of radio frequency signals circuit, for launching the signal possessing calibration power; Described calibration power is that the predetermined power exported by described emission of radio frequency signals circuit is determined;
Testing circuit, for obtaining the output power of radiofrequency signal, described radiofrequency signal is the signal obtained after directional coupler coupling in described radio-frequency channel;
Processing unit, for determining the expectation power of described radio-frequency channel based on the power of calibrating signal, is determined the calibration parameter of described radiofrequency signal by the expectation power of described radio-frequency channel and the output power of described radiofrequency signal; Described calibration parameter is used for carrying out real time calibration to the output power of described radiofrequency signal under magnetic resonance system drainage pattern.
Technical solution of the present invention also provides a kind of magnetic resonance system, comprising:
The calibrating installation of the radio-frequency channel of magnetic resonance system as above.
Compared with prior art, technical scheme of the present invention has the following advantages:
Power based on calibrating signal determines the expectation power of radio-frequency channel, the calibration parameter of described radiofrequency signal can be obtained by the expectation power of described radio-frequency channel and the real output of radiofrequency signal, and then based on the calibration parameter of described radiofrequency signal, real time calibration is carried out to the output power of described radiofrequency signal.The method is under the normal acquisition pattern of magnetic resonance system, can calibrate the radio-frequency channel of described magnetic resonance system in real time, and normally when MR imaging apparatus is dispatched from the factory, it is calibrated in prior art, need to bring back to genuine after dispatching from the factory to recalibrate, and the Acquisition Circuit gain that there is radio-frequency channel in the process of prior art alignment is along with temperature variation or the problem of change in gain that causes along with long playing aging effect, technical solution of the present invention can solve the problem, and method is simple, radio-frequency power more accurately can be obtained.
Can self-inspection stage after the initial debug phase of magnetic resonance system, start and scanning sequence run before preparatory stage obtain the calibration parameter of radiofrequency signal, under magnetic resonance system normal acquisition pattern, just can carry out real time calibration based on the calibration parameter of described radiofrequency signal to the output power of described radiofrequency signal.
After power after obtaining radiofrequency signal calibration, based on the power calculation SAR value after described radiofrequency signal calibration, effectively can ensure the accuracy that SAR value is measured, increase the confidence level of SAR value monitoring, ensure the stability that magnetic resonance system runs.
Accompanying drawing explanation
Fig. 1 is the schematic flow sheet of the calibration steps of the radio-frequency channel that technical solution of the present invention provides;
Fig. 2 is the system schematic of the magnetic resonance system that the embodiment of the present invention provides;
Fig. 3 is the schematic flow sheet of the calibration steps of the radio-frequency channel that the embodiment of the present invention provides;
Fig. 4 is the structural representation of the calibrating installation of the radio-frequency channel that the embodiment of the present invention provides.
Embodiment
In magnetic resonance system, the measurement of energy Ratios absorptivity SAR value relates to patient safety, very important, and SAR value act as the index of magnetic resonance imaging safety.Usually, the measurement of SAR value can according to the power calculation of some radiofrequency signals of drawing for monitoring RF power, Accurate Calibration or the power of measuring described radiofrequency signal will can directly affect the accurate calculating of SAR value, and then have influence on described magnetic resonance system and whether can cause to patient dangerous assessment of burning.
The rf monitoring technology that more current magnetic resonance system adopts is design separately one piece of Acquisition Circuit for radiofrequency signal before MR imaging apparatus being dispatched from the factory, to carry out radio-frequency power to it to correct with the dummy gain ensureing its rf signal reception passage when dispatching from the factory being consistent, but due to the drift in time of the aging of the parts such as integrated circuit and performance, genuine of taking back regular for the described rf monitoring unit carrying Acquisition Circuit is also needed to recalibrate, prior art cannot be calibrated by radio frequency signal in real time, and calibration steps is complicated.
For solving the problem, technical solution of the present invention provides a kind of calibration steps of radio-frequency channel of magnetic resonance system.
Fig. 1 is the schematic flow sheet of described calibration steps, and as shown in Figure 1, first perform step S1, the power based on calibrating signal determines the expectation power of described radio-frequency channel.
The power of described calibrating signal is that the predetermined power exported by the emission of radio frequency signals circuit of described magnetic resonance system is determined, power based on described calibrating signal can determine the expectation power of described radio-frequency channel, such as, the expectation power of described radio-frequency channel can be determined by the power of the expected gain of radio-frequency channel and described calibrating signal.
Perform step S2, determined the calibration parameter of described radiofrequency signal by the expectation power of described radio-frequency channel and the output power of radiofrequency signal.
Described emission of radio frequency signals circuit can export the signal for carrying out rf monitoring, described signal is through radio-frequency (RF) power amplification, directional couple parts and transmitting coil etc., and export after directional coupler coupling, radiofrequency signal described in present specification is the signal exported after directional coupler coupling in described radio-frequency channel.
The calibration parameter of described radiofrequency signal can be obtained by the output power of described radiofrequency signal and the expectation power of radio-frequency channel.Such as, the calibration parameter of corresponding described radiofrequency signal can be determined according to the difference of the power of the expectation power of described radio-frequency channel and described radiofrequency signal.
Perform step S3, under magnetic resonance system drainage pattern, the calibration parameter based on described radiofrequency signal carries out real time calibration to the output power of described radiofrequency signal.
After obtaining the calibration parameter of radiofrequency signal, under the normal acquisition pattern of magnetic resonance system, the calibration parameter based on described radiofrequency signal can carry out real time calibration to the output power of described radiofrequency signal.
The method, under the normal acquisition pattern of magnetic resonance system, can calibrate the radio-frequency channel of described magnetic resonance system in real time, and method is simple, can be obtained radio-frequency power more accurately.
For enabling above-mentioned purpose of the present invention, feature and advantage more become apparent, and are described in detail specific embodiments of the invention below in conjunction with accompanying drawing.
In the present embodiment, in order to the output power of radio frequency signal real time calibration can be carried out, the calibration parameter of corresponding described radiofrequency signal can be obtained in advance, particularly, calibration parameter can be obtained under the calibration mode of magnetic resonance system, under the drainage pattern of magnetic resonance system, the output power based on the calibration parameter radio frequency signal obtained under described calibration mode is calibrated.
Described calibration mode refers to that the object of now magnetic resonance system work obtains the calibration parameter for radiofrequency signal, instead of in order to carry out the radiofrequency signal gathering magnetic resonance system for diagnoses and treatment, preparatory stage etc. before self-inspection stage such as after the initial debug phase, start of described magnetic resonance system and scanning sequence run, the radio frequency signal acquisition calibration parameter collected when can run based on magnetic resonance system in the above-mentioned stage, then can be called the calibration mode of magnetic resonance system by the pattern that magnetic resonance system in the above-mentioned stage works.After magnetic resonance system being completed to debugging, self-inspection and the preparation before running, magnetic resonance system can be used for the radiofrequency signal data of diagnoses and treatment by normal acquisition, namely enters acquisition state, described magnetic resonance system at this moment can be claimed to be in drainage pattern.
In the present embodiment, in the calibration mode, the signal of the predetermined power exported by the emission of radio frequency signals circuit in magnetic resonance system, determine the power of calibrating signal, and then the expectation power of described radio-frequency channel is determined based on the power of calibrating signal, the calibration parameter of described radiofrequency signal is determined by the expectation power of described radio-frequency channel and the output power of radiofrequency signal; Under drainage pattern, the calibration parameter based on described radiofrequency signal carries out real time calibration to the output power of described radiofrequency signal.
Fig. 2 is the system architecture schematic diagram of the magnetic resonance system that the present embodiment provides, as shown in Figure 2, when calibrating the radio-frequency channel of magnetic resonance system, can be in the calibration mode, first exported the signal of a predetermined power by emission of radio frequency signals circuit U 11, the power of calibrating signal can be determined according to described predetermined power.The power of the signal that described emission of radio frequency signals circuit specifically exports can be controlled by control module U17, described control module U17 based on the different control sequences in magnetic resonance system, can control by sequence sequential control circuit in described magnetic resonance system the signal that described emission of radio frequency signals circuit U 11 exports different capacity.
In the present embodiment, in the calibration mode by described emission of radio frequency signals circuit U 11 export for the signal (non-calibrated signal) that gathers by exporting directional coupler U13 to after radio-frequency power amplifier U12 power amplifier.One road input signal can be divided into multipath output signals containing particular electrical circuit such as electric bridges and output to transmitting coil U14 by described directional coupler U13 inside usually.In the present embodiment, 0 degree that is divided into after directional coupler U13 process for described signal and 90 degree of quadrature phase two paths of signals are described.
Forward pulse energy to be added to by transmitting coil U14 with it patient by described export through directional coupler U13 0 degree and 90 degree of quadrature phase two paths of signals, simultaneously can reflecting part energy in described directional coupler U13, after described directional coupler U13 is coupled, again export the radiofrequency signal of equal proportion, the radiofrequency signal of the equal proportion of described output is corresponding to 0 degree that is input in directional coupler U13 and 90 degree of quadrature phase two paths of signals, concrete, 0 degree of forward direction coupled signal P0F can be exported after directional coupler U13 is coupled, 0 degree of reverse coupled signal P0R, 90 degree of forward direction coupled signal P90F and 90 degree of reverse coupled signal P90R.
The 0 degree of forward direction coupled signal P0F exported after being coupled by described directional coupler U13,0 degree of reverse coupled signal P0R, 90 degree of forward direction coupled signal P90F and 90 degree of reverse coupled signal P90R are input to testing circuit U15.
Described magnetic resonance system also comprises power divider U18, described power divider U18 can distribute the predetermined power that described radio frequency transmitter circuitry U11 exports, such as can distribute the number of the corresponding above-mentioned radiofrequency signal obtained after directional coupler U13 is coupled, in the present embodiment, 4 tunnel radiofrequency signals are obtained after directional coupler U13 is coupled, then described predetermined power can be separated the consistent power of 4 road amplitude-phase height through high-precision power divider U18 accordingly, this power is called the power of calibrating signal.
By the real power of the radiofrequency signal obtained in the power of the calibrating signal obtained after described power divider U18 process and testing circuit U15, the calibration parameter of radiofrequency signal can be obtained through processing unit U19, concrete, the expectation power of radio-frequency channel can be determined by the power of described calibrating signal, such as can according to based on magnetic resonance system performance the expected gain of predetermined radio-frequency channel and the power of described calibrating signal can obtain the expectation power of described radio-frequency channel.
After determining the expectation power of described radio-frequency channel, based on radiofrequency signal (the 0 degree of forward direction coupled signal P0F in above-mentioned testing circuit, 0 degree of reverse coupled signal P0R, 90 degree of forward direction coupled signal P90F and 90 degree of reverse coupled signal P90R) output power, just can get the calibration parameter of described radiofrequency signal, in the present embodiment, the calibration parameter of corresponding radiofrequency signal can be determined according to the difference of the power of the expectation power of described radio-frequency channel and described radiofrequency signal, in other embodiments, also other corresponding linear or nonlinear relationship can be adopted to determine the calibration parameter of corresponding described radiofrequency signal.
In described testing circuit U15, digital signal processing unit, the Acquisition Circuit of radio frequency signal and the converting unit of simulating signal and digital signal etc. can also be comprised.
After getting calibration parameter, under the normal acquisition pattern of magnetic resonance system, just can based on calibration parameter accessed in the calibration mode, to institute's Real-time Collection under drainage pattern to radiofrequency signal calibrate.
Under the normal acquisition pattern of magnetic resonance system, power after getting radiofrequency signal calibration, just can calculate SAR value by SAR computing unit U16 as shown in Figure 2, described SAR value is the radio-frequency power that patient's unit volume absorbs, according to the monitoring to SAR value, can guarantee that patient carries out the security of magnetic resonance detection, such as can set a secure threshold in advance based on experience value, when the SAR value monitored by SAR computing unit U16 exceeds described secure threshold, then illustrate that patient absorbs too much radio-frequency power, these power have the danger of human body of burning at the heat that patient body internal conversion becomes.Due in SAR computing unit U16 for calculating the performance number of the radiofrequency signal of SAR value, be through the performance number of the radiofrequency signal after real time calibration, effectively can ensure the accuracy of the performance number of the radiofrequency signal for calculating SAR value like this, the confidence level that SAR value is monitored can be ensured thus, ensure the stability that magnetic resonance system runs.
Be described the calibration steps of the radio-frequency channel that the present embodiment provides below in conjunction with Fig. 3, Fig. 3 is the schematic flow sheet of the calibration steps of the radio-frequency channel of the magnetic resonance system that the present embodiment provides.
First step S301 is performed, according to the power of the predetermined power determination calibrating signal that emission of radio frequency signals circuit exports.
Composition graphs 2 is described this step, as shown in Figure 2, can be exported the signal of a predetermined power, can determine the power of calibrating signal according to described predetermined power by the emission of radio frequency signals circuit U 11 in magnetic resonance system.
In the present embodiment, described predetermined power is designated as P0.
With in the calibration mode, by emission of radio frequency signals circuit U 11 export for the signal that gathers export after directional coupler U13 is coupled 0 degree of forward direction coupled signal P0F, 0 degree of reverse coupled signal P0R, 90 degree of forward direction coupled signal P90F and 90 degree of reverse coupled signal P90R totally 4 tunnel radiofrequency signals be example, then described predetermined power separates the consistent calibrating signal of 4 road amplitude-phase height through power divider U18, and the power of described calibrating signal is designated as P at this
calibration.Because power divider is carrying out in the process of distributing, often separate the loss that a road signal power just has several dB, the common power attenuation of power divider as two deciles is 3 dB, the power attenuation of the power divider of the quartern is 6 dB, in described the present embodiment, the power P of described calibrating signal
calibrationcan think that described predetermined power P0 deducts the value of 6 dB, i.e. P
calibration=P0-6.
Perform step S302, the power based on calibrating signal obtains the expectation power of radio-frequency channel.
The expectation power of described radio-frequency channel can pass through formula (1) and obtain.
P
expect=P
calibration+ G (1)
Wherein, P
expectfor the expectation power of radio-frequency channel, P
calibrationfor the power of calibrating signal, G is the expected gain of radio-frequency channel.
Perform step S303, determined the calibration parameter of described radiofrequency signal by the expectation power of radio-frequency channel and the output power of radiofrequency signal.
Described radiofrequency signal refers to the radiofrequency signal exported after directional coupler coupling, i.e. 0 degree of forward direction coupled signal P0F, 0 degree of reverse coupled signal P0R, 90 degree of forward direction coupled signal P90F and the 90 degree of reverse coupled signal P90R totally 4 tunnel radiofrequency signals exported after directional coupler U13 is coupled as above, can obtain should the calibration parameter of road radiofrequency signal according to the difference of the expectation power of the real power of this road radiofrequency signal and radio-frequency channel obtained above corresponding to each road radiofrequency signal.
Concrete, the calibration parameter that formula (2) obtains radiofrequency signal can be passed through.
K
n=P
expect-P
n(2)
Wherein, K
nfor the calibration parameter of radiofrequency signal, P
nfor the real power of described radiofrequency signal, n is the index value of radiofrequency signal.In the present embodiment, described n value is 4.
Perform step S304, the calibration parameter based on described radiofrequency signal determines the linear coefficient of described radiofrequency signal.
After the calibration parameter determining corresponding each radiofrequency signal, usually can determine based on the calibration parameter of described radiofrequency signal the linear calibration factor that is applied in calibration process.
In the present embodiment, the linear coefficient of described radiofrequency signal can be 10^ (K
n/ 20), K
nfor the calibration parameter of corresponding radiofrequency signal as above, then for each road radiofrequency signal, the linear coefficient of corresponding each road radiofrequency signal can be obtained accordingly.
Described step S301 to step S304 can carry out under calibration mode as above, and the power of the radiofrequency signal that namely can be obtained for obtaining under the normal acquisition pattern of magnetic resonance system by step S301 to step S304 in the calibration mode carries out the linear coefficient calibrated.
Perform step S305, under the normal acquisition pattern of magnetic resonance system, obtain the output power of radiofrequency signal.
Incorporated by reference to reference to figure 2, radiofrequency signal under the normal acquisition pattern of magnetic resonance system refers to: under the normal acquisition pattern of magnetic resonance system, control emission of radio frequency signals circuit U 11 according to the control sequence in control module U17 and export the signal being used for normal acquisition, this signal is after radio-frequency power amplifier U12 as shown in Figure 2, directional coupler U13 and transmitting coil U14, reflecting part energy in described directional coupler U13, the radiofrequency signal of the equal proportion again exported after described directional coupler U13 is coupled.In the present embodiment, the radiofrequency signal under the normal acquisition pattern of magnetic resonance system is the 0 degree of forward direction coupled signal P0F, 0 degree of reverse coupled signal P0R, 90 degree of forward direction coupled signal P90F and the 90 degree of reverse coupled signal P90R totally 4 tunnel radiofrequency signals that export after described directional coupler U13 is coupled.
Under calibration mode and drainage pattern, control module U17 can control described emission of radio frequency signals circuit U 11 and export signal for normal acquisition, difference is in the calibration mode, described control module U11 can also control the signal that described emission of radio frequency signals circuit U 11 exports predetermined power, so that determine the power of calibrating signal.
The acquisition of the power of the radiofrequency signal gathered under normal acquisition pattern can adopt method well-known to those skilled in the art to carry out, and does not do too many description at this.
Perform step S306, the power of the radiofrequency signal obtained under drainage pattern is calibrated.
After the power getting each radiofrequency signal under drainage pattern, can realize calibrating the power of described radiofrequency signal by the linear coefficient of corresponding radiofrequency signal obtained in step s 304.
The product of the linear coefficient of the power of described radiofrequency signal and described radiofrequency signal can be defined as described radiofrequency signal calibrate after power.
The power after the calibration of the 0 degree of forward direction coupled signal P0F exported after directional coupler U13 is coupled accessed under drainage pattern, 0 degree of reverse coupled signal P0R, 90 degree of forward direction coupled signal P90F and 90 degree of reverse coupled signal P90R totally 4 tunnel radiofrequency signals can be obtained by said method.
SAR value can be calculated by the SAR computing unit U16 gone out as shown in Figure 2 by the power after the calibration of above-mentioned radiofrequency signal.Namely, after step S306, step S307 can be performed.
Step S307, based on the power calculation SAR value after the radiofrequency signal calibration under drainage pattern.
In the present embodiment, SAR value can be determined according to the power after the calibration of the 0 degree of forward direction coupled signal P0F obtained under above-mentioned drainage pattern, 0 degree of reverse coupled signal P0R, 90 degree of forward direction coupled signal P90F and 90 degree of reverse coupled signal P90R 4 tunnel radiofrequency signals totally.
The parameters such as the body weight of the system total consumed power of described SAR value and magnetic resonance system, coil power dissipation and patient are relevant.Described coil power dissipation and coil energy loss are the intrinsic parameters of system, and described system total consumed power can obtain according to the power after the calibration of above-mentioned 4 tunnel radiofrequency signals.Difference based on described system total consumed power and described coil power dissipation can obtain the power of patient's actual absorption, then does ratio with the body weight of this patient, just can obtain the unit specific absorption rate of energy, i.e. described SAR value.Be specifically known by those skilled in the art according to the power calculation SAR value of radiofrequency signal, concrete grammar no longer describes in detail at this.
The calibration steps of the radio-frequency channel that the present embodiment provides, existing scheme Design and monitoring Acquisition Circuit basis on be optimized, make it possible to the factory calibration link of saving monitoring Acquisition Circuit, real time calibration can be carried out to it when magnetic resonance system normally runs, overcome Acquisition Circuit gain along with temperature variation or the change in gain that causes along with long playing aging effect, rf monitoring power more accurately can be obtained.
The method returns the probability of factory-run school standard again after can reducing magnetic resonance system product export, and then reduces the maintenance cost of maintenance system.
SAR value accessed by the method provided by the present embodiment accurately, reliably, increase the confidence level of SAR value monitoring, reduction security of system false alarm or patient are subject to the probability that the excessive danger of radio-frequency radiation is not but detected, and can ensure the stability that magnetic resonance system runs.
Further, the method simply, effectively can realize the calibration function of radio frequency passage, overcomes in prior art and needs to design complicated temperature compensation component can calibrate by radio frequency passage, effectively can reduce system development costs.
The calibration steps of corresponding above-mentioned radio-frequency channel, the embodiment of the present invention also provides a kind of calibrating installation of radio-frequency channel, Fig. 4 is the structural representation of the calibrating installation of the radio-frequency channel that the present embodiment provides, and described device comprises: emission of radio frequency signals circuit U 11, testing circuit U15, processing unit U19.
Described emission of radio frequency signals circuit U 11, for launching the signal possessing calibration power; Described calibration power is that the predetermined power exported by described emission of radio frequency signals circuit is determined;
Described testing circuit U15, for obtaining the output power of radiofrequency signal, described radiofrequency signal is the signal obtained after directional coupler coupling in described radio-frequency channel;
Described processing unit U19, for determining the expectation power of described radio-frequency channel based on the power of calibrating signal, is determined the calibration parameter of described radiofrequency signal by the expectation power of described radio-frequency channel and the output power of described radiofrequency signal; Described calibration parameter is used for carrying out real time calibration to the output power of described radiofrequency signal under magnetic resonance system drainage pattern.
Described processing unit comprises factor determination unit U21, for determining the linear coefficient of described radiofrequency signal based on the calibration parameter of described radiofrequency signal; The linear coefficient of described radiofrequency signal is for determining the power after the calibration of described radiofrequency signal.
Described device also comprises power divider U18, distributes for the predetermined power exported described emission of radio frequency signals circuit, to determine the power of calibrating signal.
Described device also comprises storage unit U20, for storing the expected gain of described radio-frequency channel, to obtain the expectation power of described radio-frequency channel.
The calibrating installation of the radio-frequency channel of corresponding above-mentioned magnetic resonance system, the embodiment of the present invention also provides a kind of magnetic resonance system, comprises the calibrating installation of the radio-frequency channel of magnetic resonance system as above.
Although the present invention discloses as above, the present invention is not defined in this.Any those skilled in the art, without departing from the spirit and scope of the present invention, all can make various changes or modifications, and therefore protection scope of the present invention should be as the criterion with claim limited range.
Claims (13)
1. a calibration steps for the radio-frequency channel of magnetic resonance system, is characterized in that, comprising:
Power based on calibrating signal determines the expectation power of described radio-frequency channel, and the power of described calibrating signal is that the predetermined power exported by the emission of radio frequency signals circuit of described magnetic resonance system is determined;
Determined the calibration parameter of described radiofrequency signal by the expectation power of described radio-frequency channel and the output power of radiofrequency signal, described radiofrequency signal is the signal obtained after directional coupler coupling in described radio-frequency channel;
Under magnetic resonance system drainage pattern, the calibration parameter based on described radiofrequency signal carries out real time calibration to the output power of described radiofrequency signal.
2. the calibration steps of the radio-frequency channel of magnetic resonance system as claimed in claim 1, it is characterized in that, the described power based on calibrating signal determines that the expectation power of described radio-frequency channel comprises:
The expectation power of described radio-frequency channel is determined based on the power of described calibrating signal and the expected gain of described radio-frequency channel.
3. the calibration steps of the radio-frequency channel of magnetic resonance system as claimed in claim 1, it is characterized in that, the power of described calibrating signal obtains in the following way:
According to the number of described radiofrequency signal, the predetermined power that described emission of radio frequency signals circuit exports is distributed, to determine the power of described calibrating signal.
4. the calibration steps of the radio-frequency channel of magnetic resonance system as claimed in claim 3, it is characterized in that, the calibration parameter of described radiofrequency signal obtains in the following way:
Obtain the power of described radiofrequency signal;
The calibration parameter of described radiofrequency signal is determined by the difference of the expectation power of described radio-frequency channel and the power of described radiofrequency signal.
5. the calibration steps of the radio-frequency channel of magnetic resonance system as claimed in claim 4, it is characterized in that, described under magnetic resonance system drainage pattern, the calibration parameter based on described radiofrequency signal carries out real time calibration to the power of described radiofrequency signal and comprises:
Calibration parameter based on described radiofrequency signal determines the linear coefficient of described radiofrequency signal;
The product of the linear coefficient of the power of described radiofrequency signal and described radiofrequency signal is defined as described radiofrequency signal calibrate after power.
6. the calibration steps of the radio-frequency channel of magnetic resonance system as claimed in claim 5, it is characterized in that, comprise: the linear coefficient being determined described radiofrequency signal by formula a (n)=10^ (k (n)/20), wherein, a (n) is the linear coefficient of described radiofrequency signal, k (n) is the calibration parameter of described radiofrequency signal, and n is the index value of described radiofrequency signal.
7. the calibration steps of the radio-frequency channel of magnetic resonance system as claimed in claim 1, it is characterized in that, the self-inspection stage of calibration parameter after the initial debug phase, start of described magnetic resonance system of described radiofrequency signal and the preparatory stage before scanning sequence operation obtain.
8. a SAR measuring method, is characterized in that, comprising:
Adopt the calibration steps of the radio-frequency channel of the magnetic resonance system as described in claim 1 to any one of claim 7, obtain the power after the calibration of described radiofrequency signal;
Based on SAR value described in the power calculation after described radiofrequency signal calibration.
9. a calibrating installation for the radio-frequency channel of magnetic resonance system, is characterized in that, comprising:
Emission of radio frequency signals circuit, for launching the signal possessing calibration power; Described calibration power is that the predetermined power exported by described emission of radio frequency signals circuit is determined;
Testing circuit, for obtaining the output power of radiofrequency signal, described radiofrequency signal is the signal obtained after directional coupler coupling in described radio-frequency channel;
Processing unit, for determining the expectation power of described radio-frequency channel based on the power of calibrating signal, is determined the calibration parameter of described radiofrequency signal by the expectation power of described radio-frequency channel and the output power of described radiofrequency signal; Described calibration parameter is used for carrying out real time calibration to the output power of described radiofrequency signal under magnetic resonance system drainage pattern.
10. the calibrating installation of the radio-frequency channel of magnetic resonance system as claimed in claim 9, is characterized in that, also comprise: power divider, distributes for the predetermined power exported described emission of radio frequency signals circuit, to determine the power of calibrating signal.
The calibrating installation of the radio-frequency channel of 11. magnetic resonance systems as claimed in claim 9, is characterized in that, also comprise: storage unit, for storing the expected gain of described radio-frequency channel, to obtain the expectation power of described radio-frequency channel.
The calibrating installation of the radio-frequency channel of 12. magnetic resonance systems as claimed in claim 9, it is characterized in that, described processing unit also comprises: factor determination unit, for determining the linear coefficient of described radiofrequency signal based on the calibration parameter of described radiofrequency signal; The linear coefficient of described radiofrequency signal is for determining the power after the calibration of described radiofrequency signal.
13. 1 kinds of magnetic resonance systems, is characterized in that, comprising: the calibrating installation of the radio-frequency channel of the magnetic resonance system as described in any one of claim 10 to 12.
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Cited By (12)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN106353585A (en) * | 2016-10-20 | 2017-01-25 | 成都前锋电子仪器有限责任公司 | Data processing circuit used for radio frequency power reflectometer |
| CN106597392A (en) * | 2016-11-25 | 2017-04-26 | 西安空间无线电技术研究所 | SAR system phase error compensation method |
| CN106712870A (en) * | 2017-01-23 | 2017-05-24 | 上海联影医疗科技有限公司 | Magnetic resonance receiving channel calibration method, calibration device and magnetic resonance equipment |
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| US11874354B2 (en) | 2021-05-13 | 2024-01-16 | Shanghai United Imaging Healthcare Co., Ltd. | Systems and methods for magnetic resonance imaging |
Citations (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN1595831A (en) * | 2004-07-08 | 2005-03-16 | 中兴通讯股份有限公司 | A method and device for intelligent antenna array calibration of TDD wireless communication system |
| CN1627650A (en) * | 2003-12-12 | 2005-06-15 | 华为技术有限公司 | Gain correction system for reception channel in radio frequency and method |
| US20060270355A1 (en) * | 2004-12-08 | 2006-11-30 | Siukai Mak | Method and system for signal quality measurement based on mean phase error magnitude of a signal |
| CN101635943A (en) * | 2008-07-24 | 2010-01-27 | 中兴通讯股份有限公司 | Method and device for detecting broadband power |
| CN102394679A (en) * | 2011-09-29 | 2012-03-28 | 西安空间无线电技术研究所 | System and method for calibrating transmission channel of satellite borne multi-beam antenna system in real time |
-
2014
- 2014-05-28 CN CN201410231484.0A patent/CN105137375B/en active Active
Patent Citations (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN1627650A (en) * | 2003-12-12 | 2005-06-15 | 华为技术有限公司 | Gain correction system for reception channel in radio frequency and method |
| CN1595831A (en) * | 2004-07-08 | 2005-03-16 | 中兴通讯股份有限公司 | A method and device for intelligent antenna array calibration of TDD wireless communication system |
| US20060270355A1 (en) * | 2004-12-08 | 2006-11-30 | Siukai Mak | Method and system for signal quality measurement based on mean phase error magnitude of a signal |
| CN101635943A (en) * | 2008-07-24 | 2010-01-27 | 中兴通讯股份有限公司 | Method and device for detecting broadband power |
| CN102394679A (en) * | 2011-09-29 | 2012-03-28 | 西安空间无线电技术研究所 | System and method for calibrating transmission channel of satellite borne multi-beam antenna system in real time |
Cited By (17)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN106353585A (en) * | 2016-10-20 | 2017-01-25 | 成都前锋电子仪器有限责任公司 | Data processing circuit used for radio frequency power reflectometer |
| CN106597392A (en) * | 2016-11-25 | 2017-04-26 | 西安空间无线电技术研究所 | SAR system phase error compensation method |
| CN106597392B (en) * | 2016-11-25 | 2019-09-06 | 西安空间无线电技术研究所 | A kind of SAR system phase error compensation method |
| CN106712870A (en) * | 2017-01-23 | 2017-05-24 | 上海联影医疗科技有限公司 | Magnetic resonance receiving channel calibration method, calibration device and magnetic resonance equipment |
| CN107219491A (en) * | 2017-07-20 | 2017-09-29 | 成都玖锦科技有限公司 | A kind of eight passage calibration modules and calibration method |
| US11366137B2 (en) | 2018-04-10 | 2022-06-21 | Xi'an Yep Telecommunication Technology, Ltd. | Temperature compensation method for SAR sensor of terminal, and terminal |
| WO2019196424A1 (en) * | 2018-04-10 | 2019-10-17 | 西安易朴通讯技术有限公司 | Temperature compensation method for sar sensor of terminal, and terminal |
| CN108983134B (en) * | 2018-05-31 | 2020-07-03 | 上海东软医疗科技有限公司 | Signal receiving channel calibration method and magnetic resonance calibration system |
| CN108983134A (en) * | 2018-05-31 | 2018-12-11 | 上海东软医疗科技有限公司 | Signal receiving channel calibration method and magnetic resonance calibration system |
| CN110554331A (en) * | 2019-08-23 | 2019-12-10 | 武汉中科牛津波谱技术有限公司 | emission phase calibration system and method of nuclear magnetic resonance instrument |
| CN110554331B (en) * | 2019-08-23 | 2022-01-11 | 武汉中科牛津波谱技术有限公司 | Emission phase calibration system and method of nuclear magnetic resonance instrument |
| CN111722171A (en) * | 2020-06-29 | 2020-09-29 | 维沃移动通信有限公司 | Electronic equipment, calibration method and calibration device |
| CN113303781A (en) * | 2021-04-30 | 2021-08-27 | 鑫高益医疗设备股份有限公司 | Gating synchronous magnetic resonance SAR value monitoring method, device, storage medium and system |
| CN113303781B (en) * | 2021-04-30 | 2022-05-13 | 鑫高益医疗设备股份有限公司 | Gating synchronization magnetic resonance SAR value monitoring method, device, storage medium and system |
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| CN113406527A (en) * | 2021-05-13 | 2021-09-17 | 北京北方华创微电子装备有限公司 | Radio frequency power supply control system, calibration method and device thereof, and semiconductor equipment |
| US11874354B2 (en) | 2021-05-13 | 2024-01-16 | Shanghai United Imaging Healthcare Co., Ltd. | Systems and methods for magnetic resonance imaging |
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