Method and device for determining radio frequency absorption rate and computer readable storage medium
By acquiring and calculating the instantaneous RF output power of a single RF pulse, the equivalent pulse width is determined to improve the accuracy of RF absorption rate calculation, thus solving the problem of insufficient accuracy of RF absorption rate and ensuring the safety of magnetic resonance imaging.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Patents(China)
- Current Assignee / Owner
- BEIJING WANDONG MEDICAL TECH CO LTD
- Filing Date
- 2023-01-17
- Publication Date
- 2026-07-14
AI Technical Summary
In existing technologies, the accuracy of radio frequency absorption rate is insufficient, which may cause harm to the human body during magnetic resonance imaging.
By acquiring the instantaneous RF output power of a single RF pulse, calculating the equivalent pulse width, and then calculating the RF absorption rate based on this equivalent pulse width, the calculation accuracy is improved.
It improves the accuracy of radio frequency absorption rate calculation and effectively prevents damage to the human body due to excessive heat, especially during magnetic resonance imaging.
Smart Images
Figure CN116087631B_ABST
Abstract
Description
Technical Field
[0001] This application relates to the field of radio frequency signal processing technology, and more specifically, to a method, apparatus, electronic device, and computer-readable storage medium for determining radio frequency absorption rate. Background Technology
[0002] Radio frequency absorptivity characterizes the absorption of radio frequency energy by a substance. Specifically, it refers to the electromagnetic radiation energy absorbed by a unit mass of substance per unit time. Internationally, the SAR value (Specific Absorption Ratio) is usually used to measure the thermal effect of terminal radiation.
[0003] It is evident that the SAR value is one of the reference bases for assessing the damage caused to matter by nuclear magnetic resonance energy. Taking magnetic resonance imaging (MRI) as an example, if the SAR value is too high during MRI scans of the human body, it can cause a burning sensation on the skin, and prolonged exposure can damage skin tissue cells. Therefore, accurate SAR value acquisition is essential for protecting the human body during MRI scans. However, the accuracy of SAR values obtained using current technology is not high enough; that is, the accuracy of the obtained radiofrequency absorptivity is not high enough. Consequently, inaccurate SAR value measurements can easily cause harm to the human body. Summary of the Invention
[0004] The purpose of this application is to provide a method, apparatus, electronic device, and computer-readable storage medium for determining radio frequency absorption rate. By acquiring the instantaneous radio frequency output power of a single radio frequency pulse in radio frequency, the equivalent pulse width of the single radio frequency pulse is determined, and the radio frequency absorption rate within a target duration is calculated based on the equivalent pulse width, thereby improving the accuracy of radio frequency absorption rate calculation.
[0005] In a first aspect, embodiments of this application provide a method for determining radio frequency absorption rate, comprising: acquiring instantaneous radio frequency output power within the duration of a single radio frequency pulse at set time intervals; calculating the equivalent pulse width of the single radio frequency pulse based on all acquired instantaneous radio frequency output power; calculating the pulse output energy of the single radio frequency pulse based on the equivalent pulse width; and calculating the radio frequency absorption rate of the radio frequency within a target duration based on the pulse output energy of the single radio frequency pulse.
[0006] The aforementioned method for determining radio frequency (RF) absorptivity improves the accuracy of RF absorptivity calculation by acquiring the instantaneous RF output power of a single RF pulse, determining the equivalent pulse width of that pulse, and calculating the RF absorptivity over the target duration based on that equivalent pulse width. This, in turn, more effectively prevents damage to targets, especially those undergoing magnetic resonance imaging (MRI), due to excessive heat.
[0007] In conjunction with the first aspect, optionally, the acquisition of the instantaneous radio frequency output power within the duration of a single radio frequency pulse includes: determining the relationship between the instantaneous radio frequency output power of the single radio frequency pulse and a power threshold; and if it is determined that the instantaneous radio frequency output power is greater than the power threshold, then acquiring the instantaneous radio frequency output power.
[0008] The above method for determining the radio frequency absorption rate determines the relationship between the instantaneous radio frequency output power and the power threshold. Only when the instantaneous radio frequency output power is greater than the power threshold is the instantaneous radio frequency output power collected. This ensures that the collection duration is equivalent to the pulse duration, thus measuring the pulse duration and facilitating subsequent calculations.
[0009] In conjunction with the first aspect, optionally, the step of acquiring the instantaneous radio frequency output power within the duration of a single radio frequency pulse further includes: if it is determined that the instantaneous radio frequency output power is less than the power threshold, then stop acquiring the instantaneous radio frequency output power; or determine the relationship between the continuous acquisition time of acquiring the instantaneous radio frequency output power and the time threshold; if it is determined that the continuous acquisition time is greater than the time threshold, then stop acquiring the instantaneous radio frequency output power.
[0010] The above-mentioned method for determining the radio frequency absorption rate stops acquisition when the instantaneous radio frequency output power is less than the power threshold or when the acquisition duration exceeds the time threshold. This allows the acquisition duration to be used as a parameter for calculating the radio frequency absorption rate within the target duration, which facilitates the calculation of the radio frequency absorption rate and improves the accuracy of the calculation.
[0011] In conjunction with the first aspect, optionally, the step of calculating the equivalent pulse width of the single radio frequency pulse based on all the instantaneous radio frequency output powers collected includes: obtaining the peak radio frequency output power of the single radio frequency pulse from all the instantaneous radio frequency output powers collected; and accumulating the product of the square of the instantaneous radio frequency output power and the time interval, and dividing by the square of the peak radio frequency output power to obtain the equivalent pulse width.
[0012] The above-mentioned method for determining the radio frequency absorption rate obtains the equivalent pulse width by accumulating the product of the square of the instantaneous radio frequency output power and the time interval, and dividing by the square of the peak radio frequency output power. The accuracy of the calculation is relatively high, which further improves the accuracy of the final calculated radio frequency absorption rate.
[0013] In conjunction with the first aspect, optionally, the step of calculating the pulse output energy of the single radio frequency pulse based on the equivalent pulse width includes: calculating the pulse output energy based on the equivalent pulse width and the peak radio frequency output power determined from the instantaneous radio frequency output power.
[0014] The above method for determining the RF absorption rate calculates the pulse output energy of a single RF pulse by multiplying the equivalent pulse width by the peak RF output power. Based on this pulse output energy, the RF absorption rate over any time period can be calculated, and the final RF absorption rate obtained is more accurate.
[0015] In conjunction with the first aspect, optionally, the step of calculating the radio frequency absorption rate of the radio frequency within a target duration based on the pulse output energy of the single radio frequency pulse includes: summing the pulse output energy of all pulses within a unit time and dividing by the unit time to obtain the unit radio frequency output power, thereby obtaining the unit radio frequency output power of the radio frequency within a unit time; and storing the unit radio frequency output power and calculating the radio frequency absorption rate based on the unit radio frequency output power.
[0016] The aforementioned method for determining the radio frequency (RF) absorption rate calculates the unit RF output power per unit time and then calculates the final RF absorption rate based on that unit RF output power. This shortens the update time of the final RF absorption rate to that unit time. Furthermore, by storing the calculated unit RF output power per unit time, the RF absorption rate for a target duration can be calculated at any time based on that unit output power, without having to re-execute the RF absorption rate determination method provided in this application embodiment from scratch, thus improving the efficiency of RF absorption rate calculation.
[0017] In conjunction with the first aspect, optionally, the step of calculating the radio frequency absorption rate based on the unit radio frequency output power includes: summing up all the unit radio frequency output powers within a target time period and dividing by the number of times the unit radio frequency output power is summed to obtain the radio frequency output power within the target time period; and calculating the radio frequency absorption rate based on the absorption coefficient of the radio frequency absorption target absorbing the radio frequency, the mass of the absorbing radio frequency portion, and the power loss coefficient of the radio frequency.
[0018] The above method for determining the radio frequency absorption rate, based on the calculated radio frequency output power within the target time, and on the absorption coefficient of the radio frequency absorption target, the mass of the absorbing radio frequency part, and the power loss coefficient of the radio frequency, further improves the accuracy of the radio frequency absorption rate.
[0019] In conjunction with the first aspect, optionally, the step of acquiring the instantaneous radio frequency output power within the duration of a single radio frequency pulse at set time intervals includes:
[0020] The FPGA collects the instantaneous radio frequency output power at the set time intervals.
[0021] The aforementioned method for determining the radio frequency absorption rate improves data acquisition efficiency and frequency by using an FPGA to collect the instantaneous radio frequency output power. Furthermore, the time interval for collecting the instantaneous radio frequency output power can be easily set on the FPGA as needed, thereby improving the accuracy of the equivalent pulse width calculation and increasing efficiency when applying this solution. Ultimately, this further enhances the accuracy of the radio frequency absorption rate calculation.
[0022] Secondly, embodiments of this application also provide an apparatus for determining radio frequency absorption rate, comprising: a data acquisition module and a calculation module. The data acquisition module is used to acquire instantaneous radio frequency output power within the duration of a single radio frequency pulse at set time intervals; the calculation module is used to calculate the equivalent pulse width of the single radio frequency pulse based on all acquired instantaneous radio frequency output power; the calculation module is further used to calculate the pulse output energy of the single radio frequency pulse based on the equivalent pulse width; and the calculation module is further used to calculate the radio frequency absorption rate of the radio frequency within a target duration based on the pulse output energy of the single radio frequency pulse.
[0023] The above embodiments provide a radio frequency absorption rate determination apparatus that has the same beneficial effects as the radio frequency absorption rate determination method provided by the first aspect or any optional embodiment of the first aspect, and will not be elaborated here.
[0024] Thirdly, embodiments of this application also provide an electronic device, including: a processor and a memory, the memory storing machine-readable instructions executable by the processor, which, when executed by the processor, perform the method described above.
[0025] The above embodiments provide an electronic device that has the same beneficial effects as the method for determining radio frequency absorption rate provided by the first aspect or any optional embodiment of the first aspect, which will not be elaborated here.
[0026] Fourthly, embodiments of this application also provide a computer-readable storage medium storing a computer program that, when executed by a processor, performs the methods described above.
[0027] The computer-readable storage medium provided in the above embodiments has the same beneficial effects as the method for determining radio frequency absorption rate provided in the first aspect or any optional embodiment of the first aspect, and will not be described in detail here.
[0028] In summary, the method, apparatus, and computer-readable storage medium for determining radio frequency (RF) absorption rate provided in this application improve the accuracy of RF absorption rate calculation by acquiring the instantaneous RF output power of a single RF pulse, determining the equivalent pulse width of that single RF pulse, and calculating the RF absorption rate over a target duration based on that equivalent pulse width. Specifically, by determining the relationship between the instantaneous RF output power and a power threshold, or the relationship between the acquisition duration and the target duration, the start and end times of acquisition are determined. This acquisition duration can then be used as a parameter for calculating the RF absorption rate over the target duration, facilitating the calculation and further improving its accuracy. Furthermore, by calculating the unit RF output power per unit time and using that unit RF output power to calculate the final RF absorption rate, the update time for the final RF absorption rate can be shortened to that unit time. Moreover, storing the calculated unit RF output power per unit time eliminates the need to re-execute the data acquisition and pulse equivalent width calculation processes at any subsequent RF absorption rate calculations, thus improving the efficiency of RF absorption rate calculation. By using FPGA to acquire instantaneous radio frequency power, the acquisition frequency and efficiency are improved, which in turn further enhances the accuracy of radio frequency calculations. Ultimately, this improves the protection capabilities for human bodies, such as those undergoing magnetic resonance imaging (MRI). Attached Figure Description
[0029] To more clearly illustrate the technical solutions of the embodiments of this application, the accompanying drawings used in the embodiments of this application will be briefly introduced below. It should be understood that the following drawings only show some embodiments of this application and should not be regarded as a limitation of the scope. For those skilled in the art, other related drawings can be obtained based on these drawings without creative effort.
[0030] Figure 1 A flowchart illustrating the method for determining radio frequency absorption rate provided in this application embodiment;
[0031] Figure 2 A first detailed flowchart of step S120 in the method for determining frequency absorption rate provided in the embodiments of this application;
[0032] Figure 3 A second detailed flowchart of step S120 in the method for determining frequency absorption rate provided in the embodiments of this application;
[0033] Figure 4 A detailed flowchart of step S140 in the method for determining frequency absorption rate provided in the embodiments of this application;
[0034] Figure 5 A detailed flowchart of step S180 in the method for determining frequency absorption rate provided in the embodiments of this application;
[0035] Figure 6 A detailed flowchart of step S182 in the method for determining frequency absorption rate provided in the embodiments of this application;
[0036] Figure 7 A functional block diagram of the radio frequency absorption rate determination device provided in the embodiments of this application;
[0037] Figure 8 This is a schematic diagram of the structure of an electronic device provided in an embodiment of this application. Detailed Implementation
[0038] The embodiments of the technical solution of this application will now be described in detail with reference to the accompanying drawings. These embodiments are only used to more clearly illustrate the technical solution of this application and are therefore merely examples, and should not be used to limit the scope of protection of this application.
[0039] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this application belongs; the terminology used herein is for the purpose of describing particular embodiments only and is not intended to limit this application.
[0040] In the description of the embodiments of this application, technical terms such as "first" and "second" are used only to distinguish different objects and should not be construed as indicating or implying relative importance or implicitly specifying the number, specific order, or primary and secondary relationship of the indicated technical features. In the description of the embodiments of this application, "multiple" means two or more, unless otherwise explicitly defined.
[0041] Please refer to Figure 1 , Figure 1 This is a flowchart illustrating a method for determining radio frequency absorption rate according to an embodiment of this application. The method for determining radio frequency absorption rate according to an embodiment of this application includes:
[0042] Step S120: Acquire the instantaneous RF output power within the duration of a single RF pulse at set time intervals.
[0043] In step S120 above, the set time interval can be 2μs, 1μs, or 3μs, etc. The duration of a single RF pulse is the time from the start to the end of that single RF pulse. The instantaneous RF output power can be obtained by acquiring the instantaneous level within the pulse duration.
[0044] Step S140: Calculate the equivalent pulse width of a single RF pulse based on all instantaneous RF output power collected.
[0045] In step S140 above, the equivalent pulse width of a single RF pulse can be the pulse width equivalent to a rectangular pulse, that is, the pulse duration equivalent to a rectangular pulse. The instantaneous RF output power of this rectangular pulse is equal to the peak RF output power of the single RF pulse. The calculation of the equivalent pulse width can be achieved by fitting a "power-time" function to the acquired instantaneous RF output power, and then obtaining the equivalent pulse width from this function. Alternatively, the peak RF output power of the pulse can be determined from all acquired instantaneous RF output powers, and the equivalent pulse width can be obtained by normalizing the instantaneous RF output power to the peak RF output power.
[0046] Step S160: Calculate the pulse output energy of a single radio frequency pulse based on the equivalent pulse width.
[0047] In step S160 above, the pulse output energy of a single RF pulse can be the product of the equivalent pulse and the peak RF output power.
[0048] Step S180: Calculate the radio frequency absorption rate within the target duration based on the pulse output energy of a single radio frequency pulse.
[0049] In step S180 above, the radio frequency (RF) absorption rate within the target duration can be the internationally accepted SAR value. According to the standards established by the IEC (International Electrotechnical Commission), it can be the RF absorption rate within 10 seconds or 6 minutes. Regarding the RF absorption rate within the target duration, the average RF transmission power within the target duration can be calculated based on the energy output of a single RF pulse, the number of pulses within the target duration, and the target duration itself. Based on the average RF transmission power within the target duration and the absorption relationship of the RF-absorbing material, the average RF absorption power of the material within the target duration can be determined. The RF absorption rate can be obtained by dividing the average RF absorption power by the mass of the RF-absorbing portion of the material. The absorption relationship depends on the power loss of the RF transmitting device, the absorption coefficient of the material, etc.; and the mass of the RF-absorbing portion of the material can be measured using a pressure sensor.
[0050] In the above implementation process, by acquiring the instantaneous RF output power of a single RF pulse, the equivalent pulse width of that single RF pulse is determined, and the RF absorption rate over the target duration is calculated based on this equivalent pulse width, thus improving the accuracy of the RF absorption rate calculation. This, in turn, more effectively prevents damage to targets, especially those undergoing magnetic resonance imaging, due to excessive heat.
[0051] Please refer to Figure 2 , Figure 2 This is a first detailed flowchart of step S120 in the method for determining frequency absorption rate provided in this application embodiment. In an optional embodiment, step S120 includes:
[0052] Step S121: Determine the relationship between the instantaneous RF output power of a single RF pulse and the power threshold.
[0053] In step S121 above, the power threshold can be set according to actual needs. Specifically, it can be implemented by using the sensitivity of detecting or acquiring the instantaneous power as the power threshold.
[0054] If it is determined that the instantaneous RF output power is greater than the power threshold, then step S123 is executed: collect the instantaneous RF output power.
[0055] In step S123 above, when the instantaneous RF output power is greater than the power threshold, the instantaneous RF output power is collected to ensure that the collection duration is equivalent to the duration of the RF pulse.
[0056] In the above implementation process, by judging the relationship between the instantaneous RF output power and the power threshold, and only when the instantaneous RF output power is greater than the power threshold, the instantaneous RF output power is collected, ensuring that the collection duration is equivalent to the pulse duration, which is equivalent to measuring the pulse duration and facilitating subsequent calculations.
[0057] Please continue to refer to Figure 2 In an optional implementation, step S120 further includes:
[0058] If the instantaneous RF output power is determined to be less than the power threshold, then step S125 is executed: stop collecting instantaneous RF output power.
[0059] In step S125 above, when the instantaneous RF output power is less than the power threshold, the acquisition of the instantaneous RF output power is stopped, so as to achieve the acquisition of the instantaneous RF output power of the RF only within the pulse duration.
[0060] Please refer to Figure 3 , Figure 3 This is a second detailed flowchart of step S120 in the method for determining frequency absorption rate provided in the embodiments of this application. Alternatively, step S120 may further include:
[0061] Step S124: Determine the relationship between the continuous acquisition time of the instantaneous RF output power and the time threshold.
[0062] In step S124 above, the time threshold can be a unit time used to calculate the unit RF output power per unit time. For example, if the set time interval is 2μs, then the unit time can be 1ms, or it can be 0.5ms or 2ms.
[0063] If the continuous collection time is determined to be greater than the time threshold, then the above step S125 is executed.
[0064] In the above steps, taking 1ms as an example, since the radio frequency output power within this 1ms unit time needs to be calculated, the time for collecting the instantaneous radio frequency output power is limited to within this unit time, so as to calculate the unit radio frequency output power within the unit time and calculate the radio frequency absorption rate within the target duration through this unit radio frequency output power.
[0065] In the above implementation process, by stopping the acquisition when the instantaneous RF output power is less than the power threshold or when the acquisition duration exceeds the time threshold, the acquisition duration can be used as a parameter for calculating the RF absorption rate within the target duration, which facilitates the calculation of the RF absorption rate and improves the accuracy of the calculation.
[0066] Please refer to Figure 4 , Figure 4 This is a detailed flowchart of step S140 in the method for determining frequency absorption rate provided in this application embodiment. In an optional embodiment, step S140 includes:
[0067] Step S141: Obtain the peak radio frequency output power of a single radio frequency pulse from all the instantaneous radio frequency output powers collected.
[0068] Step S142: Accumulate the product of the square of the instantaneous RF output power and the time interval, and divide by the square of the peak RF output power to obtain the equivalent pulse width.
[0069] In the above steps, the largest of all instantaneous RF output powers acquired is the peak RF output power. The equivalent pulse width can be calculated by accumulating these values using the following formula:
[0070] W=∫P t 2 (t)dt / P p eak 2
[0071] Where W is the value of the equivalent pulse width, P t (t) represents the power value that varies with time, specifically the instantaneous RF output power value, where t is time and P is the value of the instantaneous RF output power. peak This refers to the value of the peak radio frequency output power. And P... t(t) can be a "power-time" function obtained by fitting all the instantaneous RF output powers collected.
[0072] The essence of the above formula for calculating the equivalent pulse width is also to normalize the instantaneous RF output power of the pulse to the peak RF output power.
[0073] In the above implementation process, the equivalent pulse width is obtained by accumulating the product of the square of the instantaneous RF output power and the time interval, and then dividing by the square of the peak RF output power. The accuracy of the calculation is relatively high, which further improves the accuracy of the RF absorption rate obtained in the final calculation.
[0074] In an optional implementation, step S160 includes:
[0075] Step S161: Calculate the pulse output energy based on the equivalent pulse width and the peak RF output power determined from the instantaneous RF output power.
[0076] In step S161 above, the formula for calculating the pulse output energy can be:
[0077] U i =P peak ·W
[0078] Among them, U i P is the value of the pulse output energy. peak The value of the peak RF output power is denoted as , and the value of the equivalent pulse width is denoted as W.
[0079] In the above implementation process, the pulse output energy of a single RF pulse is calculated by multiplying the equivalent pulse width by the peak RF output power. Based on this pulse output energy, the RF absorption rate within any time period can be calculated, and the final obtained RF absorption rate is more accurate.
[0080] Please refer to Figure 5 , Figure 5 This is a detailed flowchart of step S180 in the method for determining frequency absorption rate provided in the embodiments of this application. In an optional implementation, step S180 includes:
[0081] Step S181: Accumulate the pulse output energy of all pulses within a unit time and divide by the unit time to obtain the unit RF output power, thus obtaining the unit RF output power within a unit time.
[0082] In step S181 above, for example, if the unit time is 1ms, then the RF output power in that unit time is the sum of all pulse energies within 1ms divided by 1ms, and the result is the unit RF output power in that unit time.
[0083] Step S182: Store the unit RF output power and calculate the RF absorption rate based on the unit RF output power.
[0084] In step S182 above, storing the unit RF output power within a unit time period facilitates the calculation of the RF absorption rate over a target duration at any time based on this unit output power, such as the RF absorption rate over 10 seconds or 6 minutes in the IEC standard. This avoids re-executing the steps in the aforementioned embodiments every time the RF absorption rate over the target duration is calculated. The unit RF output power can be stored in Static Random-Access Memory (SRAM).
[0085] Furthermore, if the aforementioned unit RF output power is stored in SRAM, and taking a unit time of 1ms and a target time of 10s as an example, one address unit stored in the SRAM represents the unit RF output power at 1ms. Therefore, the average RF output power over 10s requires at least 10,000 addresses. The unit RF output power in all addresses needs to be accumulated and integrated, thus requiring at least 20,000 address spaces. Considering the real-time nature of calculating RF absorption rate, the SRAM address space is often insufficient, so a ring memory approach is used for storage.
[0086] Calculating the unit RF output power per unit time and then calculating the RF absorption rate based on that unit RF output power can shorten the RF absorption rate update time interval to that unit time. For example, calculating the RF output power within 1 ms can shorten the final RF absorption rate update time to 1 ms.
[0087] In the above implementation process, the unit RF output power per unit time is calculated, and the final RF absorption rate is calculated based on that unit RF output power. This shortens the update time of the final RF absorption rate to that unit time. Furthermore, the calculated unit RF output power per unit time is stored, allowing the RF absorption rate for a target duration to be calculated at any time based on that unit output power, without having to execute the RF absorption rate determination method provided in this application embodiment from scratch, thus improving the efficiency of calculating the RF absorption rate.
[0088] Please refer to Figure 6 , Figure 6 This is a detailed flowchart of step S182 in the method for determining frequency absorption rate provided in the embodiments of this application. Step S182 includes:
[0089] Step S1821: Accumulate all unit RF output power within the target time and divide by the number of times the unit RF output power is accumulated to obtain the RF output power within the target time.
[0090] In step S1821 above, based on the duration of the unit time and the duration of the target time, the unit RF output power within the unit time is accumulated and divided by the corresponding number of times to obtain the RF output power within the target time. Taking a unit time of 1ms and a target time of 10s as an example, all unit RF output powers within the 10s are accumulated and divided by a multiple between 1ms and 10s—10000—to obtain the RF output power for the target time of 10s.
[0091] Step S1822: Calculate the radio frequency absorption rate based on the absorption coefficient of the radio frequency absorption target, the quality of the radio frequency absorption part, and the power loss coefficient of the radio frequency.
[0092] In step S1822 above, the absorption coefficient of the absorbing target refers to the ratio of the radio frequency power absorbed by the target material to the received radio frequency power, and the power loss coefficient of the radio frequency refers to the ratio of the power of the radio frequency absorbed by the absorbing target to the power emitted by the radio frequency from the radio frequency transmitting device. The calculation of the radio frequency absorption rate can be: Radio frequency absorption rate = Radio frequency output power × Power loss coefficient × Absorption coefficient ÷ Mass of the absorbing radio frequency part.
[0093] In the above implementation process, the RF output power within the target time is calculated, and the RF absorption rate is calculated based on the absorption coefficient of the RF absorption target, the quality of the RF absorption part, and the RF power loss coefficient, which further improves the accuracy of the RF absorption rate.
[0094] In an optional implementation, step S120 includes:
[0095] Step S126: The FPGA collects the instantaneous RF output power at set time intervals.
[0096] In step S126 above, since the data sampling frequency of the FPGA (Field-Programmable Gate Array) is as high as 162MHz, the instantaneous radio frequency output power of the radio frequency can be acquired by the FPGA every 2μs or even shorter time intervals.
[0097] Of course, the steps for calculating the radio frequency absorption rate described in the foregoing embodiments can be executed by an FPGA, and the judgments in the foregoing steps S121 and S124 can also be executed by the state machine in the FPGA.
[0098] In the above implementation process, by acquiring the instantaneous RF output power using an FPGA, the efficiency and frequency of data acquisition are improved. Furthermore, the time interval for acquiring the instantaneous RF output power can be easily set on the FPGA as needed, thereby improving the accuracy of the equivalent pulse width calculation and increasing the efficiency when applying this solution. Ultimately, this further improves the accuracy of the RF absorption rate calculation.
[0099] Based on the same inventive concept, please refer to Figure 7 , Figure 7 This is a functional block diagram of the radio frequency absorption rate determination device 700 provided in the embodiments of this application. The radio frequency absorption rate determination device 700 provided in the embodiments of this application includes a data acquisition module 710 and a calculation module 720.
[0100] The acquisition module 710 is used to acquire the instantaneous RF output power within the duration of a single RF pulse at a set time interval; the calculation module 720 is used to calculate the equivalent pulse width of a single RF pulse based on all acquired instantaneous RF output power; the calculation module 720 is also used to calculate the pulse output energy of a single RF pulse based on the equivalent pulse width; and the calculation module 720 is also used to calculate the RF absorption rate of the RF within the target duration based on the pulse output energy of a single RF pulse.
[0101] Please continue to refer to Figure 7 In one optional implementation, the acquisition module 710 is specifically used to: determine the relationship between the instantaneous RF output power of a single RF pulse and a power threshold; and if it is determined that the instantaneous RF output power is greater than the power threshold, then acquire the instantaneous RF output power.
[0102] Please continue to refer to Figure 7 In an optional implementation, the acquisition module 710 is more specifically used to: stop acquiring instantaneous radio frequency output power if it is determined that the instantaneous radio frequency output power is less than a power threshold; or determine the relationship between the continuous acquisition time of acquiring instantaneous radio frequency output power and a time threshold, and stop acquiring instantaneous radio frequency output power if it is determined that the continuous acquisition time is greater than the time threshold.
[0103] Please continue to refer to Figure 7 In one optional implementation, the calculation module 720 is specifically used to: obtain the peak radio frequency output power of a single radio frequency pulse from all the instantaneous radio frequency output power collected; and accumulate the product of the square of the instantaneous radio frequency output power and the time interval, and divide it by the square of the peak radio frequency output power to obtain the equivalent pulse width.
[0104] Please continue to refer to Figure 7In an optional implementation, the calculation module 720 is further configured to: calculate the pulse output energy based on the equivalent pulse width and the peak radio frequency output power determined from the instantaneous radio frequency output power.
[0105] Please continue to refer to Figure 7 In one optional implementation, the calculation module 720 is further configured to: accumulate the pulse output energy of all pulses within a unit time and divide it by the unit time to obtain the unit RF output power, thereby obtaining the unit RF output power of the RF within a unit time; and store the unit RF output power and calculate the RF absorption rate based on the unit RF output power.
[0106] Please continue to refer to Figure 7 In an optional implementation, the calculation module 720 is more specifically used to: accumulate all unit RF output power within the target time and divide by the number of times the unit RF output power is accumulated to obtain the RF output power within the target time; and calculate the RF absorption rate based on the absorption coefficient of the RF absorption target, the mass of the magnetic resonance part, and the RF power loss coefficient.
[0107] Please refer to Figure 7 In one alternative implementation, the computing module 720 includes an FPGA unit for acquiring the instantaneous radio frequency output power at set time intervals.
[0108] It should be understood that this device corresponds to the above-described method embodiment for determining radio frequency absorption rate and is capable of performing the various steps involved in the above method embodiment. The specific functions of this device can be referred to the description above, and detailed descriptions are appropriately omitted here to avoid repetition. The device includes at least one software functional module that can be stored in memory or embedded in the device's operating system (OS) in the form of software or firmware.
[0109] Based on the same inventive concept, please refer to Figure 8 , Figure 8 This is a schematic diagram of the structure of an electronic device 800 provided in an embodiment of this application. The electronic device 800 may include a memory 811, a memory controller 812, a processor 813, a peripheral interface 814, an input / output unit 818, and a display unit 816. Those skilled in the art will understand that... Figure 8 The structure shown is for illustrative purposes only and does not limit the structure of the electronic device 800. For example, the electronic device 800 may also include components that are more... Figure 8 The more or fewer components shown, or having the same Figure 8 The different configurations shown.
[0110] The aforementioned memory 811, memory controller 812, processor 813, peripheral interface 814, input / output unit 818, and display unit 816 are electrically connected directly or indirectly to each other to achieve data transmission or interaction. For example, these components can be electrically connected to each other through one or more communication buses or signal lines. The aforementioned processor 813 is used to execute executable modules stored in the memory.
[0111] The memory 811 can be, but is not limited to, Random Access Memory (RAM), Read Only Memory (ROM), Programmable Read-Only Memory (PROM), Erasable Programmable Read-Only Memory (EPROM), Electrically Erasable Programmable Read-Only Memory (EEPROM), etc. The memory 811 stores programs, and the processor 813 executes these programs upon receiving execution instructions. The methods executed by the electronic device 800, as defined in any embodiment of this application, can be applied to or implemented by the processor 813.
[0112] The aforementioned processor 813 may be an integrated circuit chip with signal processing capabilities. The processor 813 may be a general-purpose processor, including a Central Processing Unit (CPU), a Network Processor (NP), etc.; it may also be a digital signal processor (DSP), an Application Specific Integrated Circuit (ASIC), a Field-Programmable Gate Array (FPGA), or other programmable logic devices, discrete gate or transistor logic devices, or discrete hardware components. It can implement or execute the methods, steps, and logic block diagrams disclosed in the embodiments of this application. The general-purpose processor may be a microprocessor or any conventional processor.
[0113] The peripheral interface 814 described above couples various input / output devices to the processor 813 and the memory 811. In some embodiments, the peripheral interface 814, the processor 813, and the memory controller 812 can be implemented in a single chip. In other instances, they can be implemented by separate chips.
[0114] The input / output unit 818 described above is used to provide user input data. The input / output unit 818 may be, but is not limited to, a mouse and keyboard.
[0115] The aforementioned display unit 816 provides an interactive interface (e.g., a user interface) between the electronic device 800 and the user, or displays image data for the user's reference. In this embodiment, the display unit can be a liquid crystal display (LCD) or a touch display. If it is a touch display, it can be a capacitive touchscreen or a resistive touchscreen that supports single-point and multi-point touch operations. Supporting single-point and multi-point touch operations means that the touch display can sense touch operations generated simultaneously from one or more locations on the touch display and pass the sensed touch operations to the processor for calculation and processing.
[0116] The electronic device 800 in this embodiment can be used to perform the various steps in the various methods provided in the embodiments of this application.
[0117] This application also provides a computer-readable storage medium storing a computer program, which is executed by a processor to perform the above-described method.
[0118] The computer-readable storage medium can be implemented by any type of volatile or non-volatile storage device or a combination thereof, such as Static Random Access Memory (SRAM), Electrically Erasable Programmable Read-Only Memory (EEPROM), Erasable Programmable Read Only Memory (EPROM), Programmable Red-Only Memory (PROM), Read-Only Memory (ROM), magnetic storage, flash memory, magnetic disk, or optical disk.
[0119] In summary, the method, apparatus, and computer-readable storage medium for determining radio frequency (RF) absorption rate provided in this application improve the accuracy of RF absorption rate calculation by acquiring the instantaneous RF output power of a single RF pulse, determining the equivalent pulse width of that single RF pulse, and calculating the RF absorption rate over a target duration based on the equivalent pulse width. Specifically, by determining the relationship between the instantaneous RF output power and a power threshold, or the relationship between the acquisition duration and the target duration, the start and end times of acquisition are determined. This acquisition duration can then be used as a parameter for calculating the RF absorption rate over the target duration, facilitating the calculation and further improving its accuracy. Furthermore, by calculating the unit RF output power per unit time and using that unit RF output power to calculate the final RF absorption rate, the update time for the final RF absorption rate can be shortened to that unit time. Moreover, storing the calculated unit RF output power per unit time eliminates the need to re-execute the data acquisition and pulse equivalent width calculation processes whenever the RF absorption rate is calculated later, thus improving the efficiency of RF absorption rate calculation. By using FPGA to acquire instantaneous radio frequency power, the acquisition frequency is increased, which in turn further improves the accuracy of radio frequency calculations. Ultimately, this enhances the protection capabilities for human bodies undergoing procedures such as magnetic resonance imaging.
[0120] It should be understood that the disclosed apparatus and methods can also be implemented in other ways, given the several embodiments provided in this application. The apparatus embodiments described above are merely illustrative. For example, the flowcharts and block diagrams in the accompanying drawings illustrate the architecture, functionality, and operation of possible implementations of apparatus, methods, and computer program products according to various embodiments of this application. In this regard, each block in a flowchart or block diagram may represent a module, segment, or portion of code, which contains one or more executable instructions for implementing a specified logical function. It should also be noted that in some alternative implementations, the functions marked in the blocks may occur in a different order than those marked in the drawings. For example, two consecutive blocks may actually be executed substantially in parallel, or they may sometimes be executed in reverse order, depending on the functions involved. It should also be noted that each block in a block diagram and / or flowchart, and combinations of blocks in block diagrams and / or flowcharts, can be implemented using a dedicated hardware-based system that performs the specified function or action, or using a combination of dedicated hardware and computer instructions.
[0121] In addition, the functional modules in the various embodiments of this application can be integrated together to form an independent part, or each module can exist independently, or two or more modules can be integrated to form an independent part.
[0122] The above description is only an optional implementation of the embodiments of this application, but the protection scope of the embodiments of this application is not limited thereto. Any changes or substitutions that can be easily conceived by those skilled in the art within the technical scope disclosed in the embodiments of this application should be covered within the protection scope of the embodiments of this application.
Claims
1. A method for determining radio frequency absorption rate, characterized in that, include: The instantaneous radio frequency output power is collected within the duration of a single radio frequency pulse at set time intervals. Calculate the equivalent pulse width of a single radio frequency pulse based on all the instantaneous radio frequency output powers collected; Calculate the pulse output energy of the single radio frequency pulse based on the equivalent pulse width; as well as The radio frequency absorption rate within the target duration is calculated based on the pulse output energy of the single radio frequency pulse. The acquisition of instantaneous radio frequency output power within the duration of a single radio frequency pulse includes: Determine the relationship between the instantaneous RF output power of the single RF pulse and the power threshold. If it is determined that the instantaneous radio frequency output power is greater than the power threshold, then the instantaneous radio frequency output power is collected; If the instantaneous RF output power is determined to be less than the power threshold, then the acquisition of the instantaneous RF output power is stopped; or the relationship between the continuous acquisition time of the instantaneous RF output power and the time threshold is determined; if the continuous acquisition time is determined to be greater than the time threshold, then the acquisition of the instantaneous RF output power is stopped.
2. The method for determining radio frequency absorption rate according to claim 1, characterized in that, The step of calculating the equivalent pulse width of a single radio frequency pulse based on all the instantaneous radio frequency output powers collected includes: From all the instantaneous radio frequency output powers collected, the peak radio frequency output power of the single radio frequency pulse is obtained; and The equivalent pulse width is obtained by summing the product of the square of the instantaneous RF output power and the time interval, and then dividing by the square of the peak RF output power.
3. The method for determining radio frequency absorption rate according to claim 1, characterized in that, The step of calculating the pulse output energy of a single radio frequency pulse based on the equivalent pulse width includes: The pulse output energy is calculated based on the equivalent pulse width and the peak radio frequency output power determined from the instantaneous radio frequency output power.
4. The method for determining radio frequency absorption rate according to claim 1, characterized in that, The step of calculating the radio frequency absorption rate within a target duration based on the pulse output energy of the single radio frequency pulse includes: The pulse output energy of all pulses within a unit time is summed and divided by the unit time to obtain the unit RF output power, thus obtaining the unit RF output power within a unit time; and The unit RF output power is stored, and the RF absorption rate is calculated based on the unit RF output power.
5. The method for determining radio frequency absorption rate according to claim 4, characterized in that, The calculation of the radio frequency absorption rate based on the unit radio frequency output power includes: The radio frequency output power within the target time period is obtained by summing all the unit radio frequency output powers within the target time period and dividing by the number of times the unit radio frequency output power is summed; and The radio frequency absorption rate is calculated based on the absorption coefficient of the radio frequency absorption target, the mass of the radio frequency absorption section, and the power loss coefficient of the radio frequency.
6. The method for determining radio frequency absorption rate according to any one of claims 1 to 5, characterized in that, The method of acquiring instantaneous radio frequency output power within the duration of a single radio frequency pulse at set time intervals includes: The FPGA collects the instantaneous radio frequency output power at the set time intervals.
7. A device for determining radio frequency absorption rate, characterized in that, include: Acquisition module and calculation module; The acquisition module is used to acquire the instantaneous radio frequency output power within the duration of a single radio frequency pulse at a set time interval; The calculation module is used to calculate the equivalent pulse width of a single radio frequency pulse based on all the instantaneous radio frequency output powers collected. The calculation module is also used to calculate the pulse output energy of the single radio frequency pulse based on the equivalent pulse width; The calculation module is also used to calculate the radio frequency absorption rate of the radio frequency within the target duration based on the pulse output energy of the single radio frequency pulse; During the acquisition of instantaneous radio frequency output power within the duration of a single radio frequency pulse, the acquisition module is specifically used to: determine the relationship between the instantaneous radio frequency output power of the single radio frequency pulse and a power threshold; if the instantaneous radio frequency output power is determined to be greater than the power threshold, then acquire the instantaneous radio frequency output power; if the instantaneous radio frequency output power is determined to be less than the power threshold, then stop acquiring the instantaneous radio frequency output power; or determine the relationship between the continuous acquisition time of acquiring the instantaneous radio frequency output power and a time threshold; if the continuous acquisition time is determined to be greater than the time threshold, then stop acquiring the instantaneous radio frequency output power.
8. A computer-readable storage medium, characterized in that, The computer-readable storage medium stores a computer program that, when executed by a processor, performs the method as described in any one of claims 1 to 6.