Field intensity regulation method, detuning circuit, equipment, device and medium for transmitting field

Abstract

The present application relates to a method for adjusting the field intensity of a transmitting field, a detuning circuit, a device, an apparatus and a medium. The method comprises: obtaining a receiving signal of a receiving coil when a transmitting coil performs signal excitation on a target imaging area; judging the uniformity of the field intensity of the transmitting field of the transmitting coil according to the receiving signal; if the field intensity of the transmitting field is not uniform, sending a control signal to the detuning circuit of the receiving coil according to the receiving signal; the control signal is used to adjust the detuning frequency of the receiving coil to adjust the field intensity of the transmitting coil. The use of this method can improve the uniformity of the transmitting field intensity.

Description

Technical Field

[0001] The present application relates to the technical field of medical equipment, and in particular to a method for regulating field intensity of a transmitting field, a detuning circuit, equipment, a device and a medium. Background Art

[0002] Theoretically, the transmit field strength of the transmit coil in a magnetic resonance imaging device is completely uniform. However, when a target object is scanned by a magnetic resonance device, the transmit field will attenuate in the scanned object due to the physical characteristics of the scanned object, such as conductivity and high dielectric constant, resulting in an uneven transmit field.

[0003] In the related art, the transmitting coil can be designed as a multi-port feeding mode, and the amplitude or phase of the feeding of each port can be adjusted to make the transmission field intensity of the transmitting coil more uniform.

[0004] However, the uniformity of the emission field intensity obtained by the related art is not high. Summary of the invention

[0005] Based on this, it is necessary to provide a field intensity regulation method, detuning circuit, equipment, device and medium for a transmitting field in order to address the above technical problems, so as to improve the uniformity of the transmitting field intensity.

[0006] In a first aspect, the present application provides a method for adjusting field intensity of a transmission field, the method comprising:

[0007] When the transmitting coil excites the target imaging area with a signal, a receiving signal of the receiving coil is obtained;

[0008] Determine the uniformity of the field strength of the transmitting field of the transmitting coil according to the received signal;

[0009] If the field strength of the transmitting field is uneven, a control signal is sent to the detuning circuit of the receiving coil according to the received signal; the control signal is used to adjust the detuning frequency of the receiving coil to adjust the field strength of the transmitting coil.

[0010] In one embodiment, determining the uniformity of the field strength of the transmitting field of the transmitting coil according to the received signal includes:

[0011] Generate a signal field strength distribution diagram according to the received signal;

[0012] According to the signal field strength distribution diagram, the field strength uniformity of the transmitting field of the transmitting coil is determined.

[0013] In one embodiment, determining the field strength uniformity of the transmitting field of the transmitting coil according to the signal field strength distribution diagram includes:

[0014] If the number of changes in the field intensity level in the area directly below the center of the receiving coil in the signal field intensity distribution diagram is greater than or equal to a preset number, it is determined that the field intensity of the transmitting field of the transmitting coil is uneven;

[0015] If, in the signal field strength distribution diagram, the number of field strength level changes in the area directly below the center of the receiving coil is less than a preset number, it is determined that the field strength of the transmitting field of the transmitting coil is uniform.

[0016] In one embodiment, the detuning circuit includes a varactor diode, and sending a control signal to the detuning circuit of the receiving coil according to the received signal includes:

[0017] Determine the uniform quantized value of the field intensity of the transmitting field of the transmitting coil according to the received signal;

[0018] Determining a detuning frequency adjustment value according to a difference between a uniform quantized value of field intensity of the transmitting field and a uniform quantized value of target field intensity;

[0019] Determining a voltage adjustment value according to a capacitance adjustment value corresponding to the detuned frequency adjustment value;

[0020] According to the voltage adjustment value, a voltage control signal is sent to the varactor diode.

[0021] In a second aspect, the present application also provides a detuning circuit for a receiving coil. The detuning circuit for the receiving coil includes a tuning circuit and a parallel resonant circuit, the parallel resonant circuit includes a varactor, the input end of the tuning circuit is connected to the output end of the controller, the output end of the tuning circuit is connected to the first end of the parallel resonant circuit, and the second end of the parallel resonant circuit is connected to the receiving coil; the varactor is arranged at one end of the parallel resonant circuit away from the receiving coil;

[0022] The controller is used to send a control signal to the varactor diode according to the reception signal of the receiving coil; the control signal is used to adjust the detuning frequency of the receiving coil to adjust the field strength of the transmitting coil.

[0023] In one embodiment, the parallel resonant circuit includes a resonant inductor, a resonant capacitor, a diode group and a first inductor, the first end of the resonant inductor is respectively connected to the output end of the tuning circuit, the second end of the resonant inductor is connected to the first end of the varactor diode, the second end of the varactor diode is respectively connected to the first end of the first inductor and the first end of the diode group, the second end of the first inductor and the second end of the diode group are both connected to the second end of the resonant capacitor.

[0024] In one embodiment, the tuning circuit includes a second inductor, a third inductor and a capacitor, the first end of the second inductor is connected to the output end of the controller, the second end of the second inductor is respectively connected to the first end of the third inductor and the first end of the capacitor, the second end of the third inductor is connected to the first end of the parallel resonant capacitor, and the second end of the capacitor is grounded.

[0025] In a third aspect, the present application further provides a magnetic resonance device, which includes the content of the detuning circuit of the receiving coil in any one of the second aspects above.

[0026] In a fourth aspect, the present application further provides a field intensity adjustment device for a transmitting field, the device comprising:

[0027] An acquisition module, used for acquiring a reception signal of a receiving coil when the transmitting coil excites a target imaging area with a signal;

[0028] A determination module, used to determine the field strength uniformity of the transmitting field of the transmitting coil according to the received signal;

[0029] The transmitting module is used to send a control signal to the detuning circuit of the receiving coil according to the received signal when the field strength of the transmitting field is uneven. The control signal is used to adjust the detuning frequency of the receiving coil to adjust the field strength of the transmitting coil.

[0030] In a fifth aspect, the present application further provides a controller, which includes a memory and a processor, wherein the memory stores a computer program, and when the processor executes the computer program, the content of any one of the methods for adjusting the intensity of a transmitting field in the first aspect is implemented.

[0031] In a sixth aspect, the present application further provides a computer-readable storage medium having a computer program stored thereon, which, when executed by a processor, implements the content of any one of the methods for adjusting the intensity of a transmitting field in the first aspect.

[0032] In a seventh aspect, the present application further provides a computer program product, including a computer program, which, when executed by a processor, implements the content of any one of the methods for adjusting the intensity of a transmitting field in the first aspect.

[0033] The above-mentioned method, detuning circuit, equipment, device and medium for adjusting the field intensity of the transmitting field obtain the receiving signal of the receiving coil when the transmitting coil performs signal excitation on the target imaging area; determine the uniformity of the field intensity of the transmitting field of the transmitting coil according to the receiving signal; if the field intensity of the transmitting field is uneven, send a control signal to the detuning circuit of the receiving coil according to the receiving signal; the control signal is used to adjust the detuning frequency of the receiving coil to adjust the field intensity of the transmitting coil. The method can accurately determine whether the receiving coil affects the field intensity of the transmitting field of the transmitting coil through the receiving signal of the receiving coil, so as to accurately determine whether the field intensity of the transmitting field of the transmitting coil is uniform. In the case of unevenness, a control signal can be accurately generated based on the receiving signal, and the detuning frequency of the receiving coil can be accurately adjusted through the control signal, so as to accurately adjust the field intensity of the transmitting field to improve the uniformity of the transmitting field intensity. BRIEF DESCRIPTION OF THE DRAWINGS

[0034] Figure 1 is a schematic diagram of a receiving coil in a conventional magnetic resonance imaging device in one embodiment;

[0035] Figure 2 A diagram showing an application environment of a method for adjusting field intensity of a transmitting field in an embodiment;

[0036] Figure 3 It is a flow chart of a method for adjusting field intensity of a transmitting field in one embodiment;

[0037] Figure 4 A schematic diagram showing a comparison of magnetic fields between a receiving coil and a transmitting coil in one embodiment;

[0038] Figure 5 A schematic diagram showing a comparison of magnetic fields between a receiving coil and a transmitting coil in one embodiment;

[0039] Figure 6 A schematic diagram showing a comparison of magnetic fields between a receiving coil and a transmitting coil in one embodiment;

[0040] Figure 7 It is a flow chart of a method for adjusting field intensity of a transmitting field in one embodiment;

[0041] Figure 8 is a schematic diagram of a signal field strength distribution diagram in one embodiment;

[0042] Fig. 9 is a schematic diagram of a signal field strength distribution diagram in one embodiment;

[0043] Fig.10 is a schematic diagram of a signal field strength distribution diagram in one embodiment;

[0044] Fig.11It is a flow chart of a method for adjusting field intensity of a transmitting field in one embodiment;

[0045] Fig.12 It is a flow chart of a method for adjusting field intensity of a transmitting field in one embodiment;

[0046] Fig.13 It is a flow chart of a method for adjusting field intensity of a transmitting field in one embodiment;

[0047] Fig.14 is a detuned circuit diagram of a receiving coil in one embodiment;

[0048] Fig.15 A parallel resonant circuit diagram in one embodiment;

[0049] Fig.16 A tuning circuit diagram in one embodiment;

[0050] Fig.17 is a circuit diagram of a receiving coil in one embodiment;

[0051] Fig.18 is a schematic structural diagram of a magnetic resonance device in one embodiment;

[0052] Fig.19 is a schematic structural diagram of a magnetic resonance device including two receiving coils in one embodiment;

[0053] Fig. 20 is a schematic structural diagram of a magnetic resonance device including two receiving coils in one embodiment;

[0054] Fig.21 is a schematic diagram of a signal field strength distribution diagram in one embodiment;

[0055] Fig. 22 It is a structural block diagram of a field intensity adjustment device of a transmitting field in an embodiment.

[0056] Description of reference numerals:

[0057] 10: Detuning circuit of receiving coil; 11: Tuning circuit;

[0058] L2: second inductor; L3: third inductor;

[0059] C1: capacitor; 12: parallel resonant circuit;

[0060] L: resonant inductance; C: resonant capacitance;

[0061] 121: diode group; L1: first inductor;

[0062] 13: Varactor diode; 14: Controller;

[0063] 15: receiving coil; 17: impedance matching circuit;

[0064] 18: Signal amplifier. DETAILED DESCRIPTION

[0065] In order to make the purpose, technical solution and advantages of the present application more clearly understood, the present application is further described in detail below in conjunction with the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain the present application and are not used to limit the present application.

[0066] Before introducing the technical solution of the present application in detail, a brief introduction to the background technology of the present application is first given.

[0067] During the magnetic resonance imaging process, it is necessary to use the transmitting coil in the magnetic resonance device to excite the target imaging area to obtain the magnetic resonance image of the target imaging area. Theoretically, the transmitting field intensity of the transmitting coil is completely uniform in the acquisition area, so the excited signal is also uniform, and the quality of the obtained magnetic resonance image is high. However, in the actual excitation process, due to the design limitations of the transmitting coil in the magnetic resonance device, the body shape of the target object, the target part and the strength of the magnetic resonance field, the field strength uniformity of the transmitting field is often unsatisfactory. In addition, generally speaking, the target object itself has the physical properties of conductivity and high dielectric constant. This characteristic will cause the transmitting field to have an attenuated standing wave effect in the target object, which will cause the transmitting field to be uneven. And the unevenness caused by this reason will become more and more severe with the increase of the field strength. In ultra-high field strengths such as 5T or 7T, the unevenness of the transmitting field caused by this effect cannot be completely avoided.

[0068] Figure 1 This is a schematic diagram of a receiving coil in a conventional magnetic resonance imaging device. Figure 1 The circular area 15 in the figure is the receiving coil 15 in the magnetic resonance imaging device. The transmitting coil in the magnetic resonance imaging device is not shown in the figure. However, the dotted line part in the figure represents the magnetic field emitted by the transmitting coil. Assume that the current on the transmitting coil is Ie jφ , the magnetic field B emitted by the transmitting coil and the current Ie j φ The receiving coil will be cut by the magnetic flux of the magnetic field B emitted by the transmitting coil, and a voltage V will be generated at the port. c , and generates a current I in the receiving coil that cancels out the magnetic field B c In this way, the receiving coil will also generate a magnetic field B C , the magnetic field B generated by the receiving coil C It will affect the uniformity of the magnetic field B emitted by the transmitting coil. cWhen the voltage is greater than the preset voltage threshold, the diode on the receiving coil will be turned on, and the inductor L and the capacitor C form a parallel resonant circuit 12. An impedance matching circuit 17 and a signal amplifier 18 are provided between the receiving coil 15 and the controller. Under ideal conditions, the parallel resonant circuit formed by the inductor L and the capacitor C has no loss, and an infinite impedance will be equivalent to the receiving coil, making the coil in an open circuit state. At this time, the parallel resonant circuit is in a detuned state.

[0069] Assuming that the receiving frequency is w0, the induced current I on the coil c It can be expressed as:

[0070]

[0071]

[0072]

[0073] Among them, Z in Indicates the equivalent impedance value of the parallel resonant frequency; w LC represents the frequency of parallel resonance; w0 represents the receiving frequency of the receiving coil.

[0074] In order to ensure the quality of magnetic resonance images, it is necessary to adjust the uniformity of the intensity of the transmitting field of the transmitting coil to ensure the uniformity of the intensity of the transmitting field of the transmitting coil, thereby improving the accuracy of magnetic resonance imaging and ensuring the quality of magnetic resonance imaging. In the related art, multiple ports can be set on the transmitting coil, each port corresponds to an adjustment circuit, and each adjustment circuit adjusts the amplitude or phase of the power fed to each port. Through the synergistic effect of multiple adjustment circuits, the intensity of the transmitting field of the transmitting coil is made more uniform.

[0075] In order to more accurately adjust the transmission field strength of the transmitting coil, the present application proposes a method for adjusting the field strength of the transmitting field, which can accurately determine whether the transmitting field is uniform based on the receiving signal of the receiving coil. In the case of unevenness, the output control signal adjusts the detuning frequency of the receiving coil, thereby improving the uniformity of the transmission field strength. The content of the method for adjusting the field strength of the transmitting field in the present application is introduced in detail below.

[0076] The field intensity adjustment method of the transmitting field provided in the embodiment of the present application can be applied to Figure 2In the application environment shown. For example, the controller may be a server, a personal computer, a laptop, a smart phone, a tablet computer, a smart mobile phone, etc. The controller may include a processor, a memory and a network interface connected by a system bus or wirelessly. Among them, the processor of the controller is used to provide computing and control capabilities. The memory of the controller may include a non-volatile storage medium and an internal memory. The non-volatile storage medium stores an operating system, a computer program and a database. The internal memory provides an environment for the operation of the operating system and the computer program in the non-volatile storage medium. The database of the controller is used to store data in the field intensity adjustment process of the launch site. The network interface of the controller is used to communicate with an external terminal through a network connection, and the computer program is executed by the processor to implement a method for adjusting the field intensity of the launch site. Among them, the controller can be implemented with an independent controller or a controller cluster composed of multiple controllers. It should be noted that the memory of the controller is not limited to the above-mentioned memory, and may also include a high-speed random access memory, a volatile solid-state memory, etc. In addition, the composition architecture of the controller is not limited to the above-mentioned situation, and some components may be added or omitted.

[0077] In one embodiment, Figure 3 As shown, a method for adjusting the field intensity of a transmitting field is provided, and the method is applied to Figure 2 The controller in the example is used to illustrate the following steps:

[0078] S201, when the transmitting coil performs signal excitation on the target imaging area, a receiving signal of the receiving coil is obtained.

[0079] In this embodiment, when the magnetic resonance device scans the target part, the transmitting coil will excite the target imaging area with a signal, the transmitting coil will generate a magnetic field, and the receiving coil will be cut by the magnetic flux of the magnetic field emitted by the transmitting coil, generating a current on the receiving coil. The controller can obtain the current of the receiving coil through a current measuring device, or can obtain the voltage on the receiving coil through a voltage measuring device, or can obtain the receiving frequency and parallel resonant frequency of the receiving coil based on the current and voltage. The current, voltage, receiving frequency and parallel resonant frequency on the receiving coil are used as the receiving signal of the receiving coil.

[0080] S202: Determine the field strength uniformity of the transmitting field of the transmitting coil according to the received signal.

[0081] Among them, the field strength uniformity of the transmitting field of the transmitting coil is related to whether the receiving coil generates a magnetic field. When the receiving coil generates a magnetic field, it will affect the field strength uniformity of the transmitting field; when the receiving coil does not generate a magnetic field, it will not affect the field strength uniformity of the transmitting field.

[0082] In this embodiment, when the received signal is the received frequency of the receiving coil and the parallel resonance frequency, the controller can compare the received frequency of the receiving coil with the parallel resonance frequency, and determine whether the field strength of the transmitting field of the transmitting coil is uniform according to the comparison result. Among them, when the parallel resonance frequency w LC is the same as the received frequency w0 of the receiving coil, the induced current I c is 0, and the receiving coil will not affect the transmitting field. At this time, the field strength of the transmitting field is uniform. When the parallel resonance frequency w LC is not the same as the received frequency w0 of the receiving coil, the receiving coil and the induced current I c generate a magnetic field proportional to it. This magnetic field is superimposed on the magnetic field of the transmitting field to affect it. At this time, the field strength of the transmitting field is not uniform.

[0083] Figure 4-Figure 6 FIG. is a schematic diagram of the magnetic field comparison between the receiving coil and the transmitting coil. The abscissa in the figure represents the real part, and the ordinate represents the imaginary part. When w LC = w0, Figure 4 the receiving coil in is in an equivalent open circuit state, and no magnetic field is generated on the receiving coil, so it will not affect the magnetic field generated by the transmitting coil. The position of the magnetic field generated by the transmitting coil on the complex plane is as shown by the dash-dotted line in Figure 4 , and the actual magnetic field in the target imaging area is the solid arrow in the figure. When w LC < w0, the magnetic field generated by the receiving coil is as shown in Figure 5 , and the actual magnetic field in the target imaging area is enhanced as shown by the solid arrow. When w LC > w0, the magnetic field generated by the receiving coil is as shown in Figure 6 , and the actual magnetic field in the target imaging area is weakened as shown by the solid arrow.

[0084] S203. If the field strength of the transmitting field is not uniform, a control signal is sent to the detuning circuit of the receiving coil according to the received signal; the control signal is used to adjust the detuning frequency of the receiving coil to adjust the field strength of the transmitting coil.

[0085] In this embodiment, when it is determined that the field strength of the transmitting field is not uniform, the controller can determine the adjustment value of the detuning frequency of the receiving coil according to the received signal of the receiving coil. And based on the adjustment value of the detuning frequency, a control signal is generated and sent to the detuning circuit of the receiving coil. After receiving the control signal, the detuning circuit adjusts the detuning frequency of the receiving coil based on the control signal to achieve the purpose of adjusting the field strength of the transmitting coil.

[0086] In the above-mentioned method for adjusting the field intensity of the transmitting field, when the transmitting coil performs signal excitation on the target imaging area, the receiving signal of the receiving coil is obtained; according to the receiving signal, the uniformity of the field intensity of the transmitting field of the transmitting coil is determined; if the field intensity of the transmitting field is uneven, a control signal is sent to the detuning circuit of the receiving coil according to the receiving signal; the control signal is used to adjust the detuning frequency of the receiving coil to adjust the field intensity of the transmitting coil. This method can accurately determine whether the receiving coil affects the field intensity of the transmitting field of the transmitting coil through the receiving signal of the receiving coil, so as to accurately determine whether the field intensity of the transmitting field of the transmitting coil is uniform. In the case of unevenness, a control signal can be accurately generated based on the receiving signal, and the detuning frequency of the receiving coil can be accurately adjusted through the control signal, so as to accurately adjust the field intensity of the transmitting field to improve the uniformity of the transmitting field intensity.

[0087] Based on the above embodiments, this embodiment is to Figure 2 The relevant contents of step S202 "determining the field strength uniformity of the transmitting field of the transmitting coil according to the received signal" are introduced and explained. Figure 7 As shown, as a non-limiting example, the above step S202 may include the following content:

[0088] S301, generating a signal strength distribution diagram according to a received signal.

[0089] The field intensity distribution diagram refers to a schematic diagram of the distribution of the field intensity in the target imaging area.

[0090] In this embodiment, after receiving the receiving signal from the receiving coil, the controller can simulate and obtain a signal field strength distribution diagram corresponding to the receiving signal based on the receiving signal. Figure 8-10 A schematic diagram showing the signal field strength distribution diagram under different situations. Different grayscales in the figure represent field strengths of different intensities. The higher the grayscale value, the stronger the corresponding field strength; the lower the grayscale value, the weaker the corresponding field strength. Figure 8 Contains 4 different grayscale field strengths, Fig. 9 Contains multiple field intensities of different gray levels, Fig.10 It also contains multiple field intensities with different gray levels.

[0091] S302: Determine the field strength uniformity of the transmitting field of the transmitting coil according to the signal field strength distribution diagram.

[0092] In this embodiment, the controller can obtain the highest field strength and the lowest field strength in the signal field strength distribution map, calculate the difference between the highest field strength and the lowest field strength, and if the difference is greater than a preset threshold, it can be determined that the field strength of the transmitting field of the transmitting coil is uneven; if the difference is less than or equal to the preset threshold, it can be determined that the field strength of the transmitting field of the transmitting coil is uniform. Alternatively, the controller can obtain the number of field strength level changes in the area directly below the center position of the receiving coil in the signal field strength distribution map, and if the number of field strength level changes is greater than or equal to the preset number, it is determined that the field strength of the transmitting field of the transmitting coil is uneven; if the number of field strength level changes is less than the preset number, it is determined that the field strength of the transmitting field of the transmitting coil is uniform.

[0093] In the above-mentioned method for adjusting the field intensity of the transmitting field, a signal field intensity distribution diagram is generated according to the received signal; and the field intensity uniformity of the transmitting field of the transmitting coil is determined according to the signal field intensity distribution diagram. The method can observe the field intensity distribution more clearly and intuitively based on the signal field intensity distribution diagram generated by the received signal, so that the field intensity uniformity of the transmitting field of the transmitting coil can be accurately determined based on the signal field intensity distribution diagram.

[0094] Based on the above embodiments, this embodiment is to Figure 3 The relevant contents of step S302 "determining the field strength uniformity of the transmitting field of the transmitting coil according to the received signal" are introduced and explained. Fig.11 As shown, as a non-limiting example, the above step S302 may include the following content:

[0095] S401, if the number of changes in the field intensity level in the area directly below the center of the receiving coil in the signal field intensity distribution diagram is greater than or equal to a preset number, it is determined that the field intensity of the transmitting field of the transmitting coil is uneven.

[0096] In this embodiment, the controller can analyze the signal field strength distribution map to obtain the number of field strength level changes between the area directly below the center position of the receiving coil and the center position of the signal field strength distribution map. The obtained number of level changes is compared with the preset number of times. If the number of level changes is greater than or equal to the preset number of times, it is determined that the number of field strength level changes is large, that is, the controller can determine that the field strength of the transmitting field of the transmitting coil is uneven.

[0097] S402: If, in the signal field strength distribution diagram, the number of field strength level changes in the area directly below the center of the receiving coil is less than a preset number, it is determined that the field strength of the transmitting field of the transmitting coil is uniform.

[0098] In this embodiment, when the number of field strength level changes between the area directly below the center position of the receiving coil and the center position of the signal field strength distribution diagram is less than the preset number, it can be determined that the number of field strength level changes is small, that is, the controller can determine that the field strength of the transmitting field of the transmitting coil is more uniform. Figure 8-Figure 10 ,from Figure 8 It can be seen that the level changes three times; Fig. 9 It can be seen that the number of level changes is 2 times; from Fig.10 It can be seen that the number of level changes is 5. Fig. 9 The field strength distribution of the transmitting field of the transmitting coil corresponding to the signal field strength distribution diagram is the most uniform. Figure 8 Secondly, Fig.10 The field strength distribution is the most uneven.

[0099] In the above-mentioned method for adjusting the field intensity of the transmitting field, if the number of changes in the field intensity level in the area directly below the center position of the receiving coil in the signal field intensity distribution diagram is greater than or equal to the preset number of times, it is determined that the field intensity of the transmitting field of the transmitting coil is uneven; if the number of changes in the field intensity level in the area directly below the center position of the receiving coil in the signal field intensity distribution diagram is less than the preset number of times, it is determined that the field intensity of the transmitting field of the transmitting coil is uniform. This method can accurately obtain the number of changes in the field intensity level in the area directly below the center position of the receiving coil through the signal field intensity distribution diagram. And by comparing the number of changes in the field intensity level with the preset number, the relationship between the number of changes in the field intensity level and the preset number can be accurately analyzed, so as to accurately determine whether the field intensity of the transmitting field of the transmitting coil is uniform.

[0100] Based on the above embodiments, this embodiment is to Figure 2 The relevant contents of step S203 "if the field strength of the transmitting field is uneven, sending a control signal to the detuning circuit of the receiving coil according to the received signal" are introduced and explained. Fig.12 As shown, as a non-limiting example, the above step S203 may include the following content:

[0101] S501, determining a uniform quantized value of the field intensity of the transmitting field of the transmitting coil according to the received signal.

[0102] In this embodiment, the controller can determine the number of changes in the field intensity level in the area directly below the center position of the receiving coil based on the field intensity distribution diagram generated by the received signal. Based on the mapping relationship between the number of changes and the uniform quantization value of the field intensity, the uniform quantization value of the field intensity of the transmitting field of the transmitting coil corresponding to the number of changes in the field intensity level is determined. Alternatively, the controller can also input the field intensity distribution diagram generated by the received signal into a preset uniform quantization value determination model, and use the uniform quantization value determination model to analyze the field intensity distribution diagram to determine the uniform quantization value of the field intensity of the transmitting field of the transmitting coil corresponding to the field intensity distribution diagram.

[0103] S502: Determine a detuning frequency adjustment value according to a difference between a uniform quantized value of field intensity of the transmitting field and a uniform quantized value of target field intensity.

[0104] Among them, the target field strength uniformity quantization value represents the field strength uniformity of the transmitting field after field strength adjustment.

[0105] In this embodiment, after determining the target field strength uniform quantization value, the controller can calculate the difference between the field strength uniform quantization value of the transmitting field and the target field strength uniform quantization value to obtain the adjustment value of the field strength uniform quantization value. Then, based on the corresponding relationship between the detuned frequency and the field strength uniform quantization value, the detuned frequency adjustment value corresponding to the adjustment value of the field strength uniform quantization value can be determined.

[0106] S503: Determine a voltage adjustment value according to the capacitance adjustment value corresponding to the detuned frequency adjustment value.

[0107] In this embodiment, since the controller adjusts the capacitance value of the varactor diode, the controller can determine the capacitance adjustment value corresponding to the detuning frequency adjustment value based on the relationship between the detuning frequency and the capacitance, and then determine the voltage adjustment value output by the controller according to the capacitance adjustment value.

[0108] S504, sending a voltage control signal to the varactor diode according to the voltage adjustment value.

[0109] In this embodiment, after obtaining the voltage adjustment value, the controller can determine the target voltage value according to the current voltage value and the voltage adjustment value, adjust the current voltage value to the target voltage value, and send a voltage control signal to the varactor diode based on the target voltage value.

[0110] In the above-mentioned method for adjusting the field intensity of the transmitting field, the uniform quantized value of the field intensity of the transmitting field of the transmitting coil is determined according to the received signal; the detuning frequency adjustment value is determined according to the difference between the uniform quantized value of the field intensity of the transmitting field and the uniform quantized value of the target field intensity; the voltage adjustment value is determined according to the capacitance adjustment value corresponding to the detuning frequency adjustment value; and the voltage control signal is sent to the varactor diode according to the voltage adjustment value. Based on the received signal, the method can accurately obtain the uniform quantized value of the field intensity of the transmitting field. Based on the uniform quantized value of the field intensity and the uniform quantized value of the target field intensity, the adjustment value of the detuning frequency can be accurately determined. Afterwards, based on the capacitance adjustment value corresponding to the detuning frequency adjustment value, the voltage adjustment value is accurately determined, so that the voltage control signal can be accurately determined based on the voltage adjustment value, and the capacitance of the varactor diode can be accurately controlled based on the voltage adjustment signal.

[0111] In one embodiment, the above-mentioned transmission field intensity adjustment method is described in detail. Fig.13 As shown, the method may include:

[0112] S601, acquiring a reception signal of a receiving coil when the transmitting coil excites a target imaging area with a signal;

[0113] S602, generating a signal strength distribution diagram according to the received signal;

[0114] S603, if the number of changes in the field intensity level in the area directly below the center of the receiving coil in the signal field intensity distribution diagram is greater than or equal to a preset number, it is determined that the field intensity of the transmitting field of the transmitting coil is uneven;

[0115] S604, determining a uniform quantized value of the field intensity of the transmitting field of the transmitting coil according to the received signal;

[0116] S605, determining a detuning frequency adjustment value according to a difference between a uniform quantized value of field intensity of the transmitting field and a uniform quantized value of target field intensity;

[0117] S606, determining a voltage adjustment value according to a capacitance adjustment value corresponding to the detuned frequency adjustment value;

[0118] S607, sending a voltage control signal to the varactor diode according to the voltage adjustment value.

[0119] S608: If the number of changes in the field intensity level in the area directly below the center of the receiving coil in the signal field intensity distribution diagram is less than a preset number, it is determined that the field intensity of the transmitting field of the transmitting coil is uniform.

[0120] It should be understood that, although the steps in the flowcharts involved in the above embodiments are displayed in sequence according to the indication of the arrows, these steps are not necessarily executed in sequence according to the order indicated by the arrows. Unless there is a clear explanation in this article, the execution of these steps is not strictly limited in order, and these steps can be executed in other orders. Moreover, at least a part of the steps in the flowcharts involved in the above embodiments may include multiple steps or multiple stages, and these steps or stages are not necessarily executed at the same time, but can be executed at different times, and the execution order of these steps or stages is not necessarily carried out in sequence, but can be executed in turn or alternately with other steps or at least a part of the steps or stages in other steps.

[0121] In one embodiment, Fig.14As shown, a detuning circuit 10 of a receiving coil is provided, the detuning circuit 10 includes a tuning circuit 11 and a parallel resonant circuit 12, the parallel resonant circuit 12 includes a varactor 13, an input end of the tuning circuit 11 is connected to an output end of a controller 14, the output end of the tuning circuit 11 is connected to a first end of the parallel resonant circuit 12, and a second end of the parallel resonant circuit 12 is connected to a receiving coil 15; the varactor 13 is arranged at an end of the parallel resonant circuit 12 away from the receiving coil 15; the controller 14 is used to send a control signal to the varactor 13 according to a receiving signal of the receiving coil 15; the control signal is used to adjust the detuning frequency of the receiving coil 15 to adjust the field strength of the transmitting coil.

[0122] The detuning circuit 10 is in a detuning state when the receiving coil 15 is in an open circuit state. The tuning circuit 11 adjusts the frequency of the parallel resonant circuit 12 based on the control signal sent by the controller 14 to adjust the detuning frequency of the receiving coil 15. When the detuning frequency of the receiving coil 15 changes, the field strength of the transmitting coil will also change accordingly, thereby achieving the purpose of adjusting the field strength of the transmitting coil. The tuning circuit 11 may include a tuning capacitor and other tuning circuit elements.

[0123] The parallel resonant circuit 12 includes an inductor, a capacitor and a varactor 13 connected in parallel, and may also include other electronic components except the inductor and the capacitor. For example, other electronic components may include a bidirectional diode. Among them, the two ends of the capacitor are connected to the receiving coil 15, and the inductor is arranged at one end away from the receiving coil 15. The bidirectional diode can be arranged between the second end of the inductor and the second end of the capacitor. Therefore, the varactor 13 and the inductor are arranged on the same side, and the varactor 13 can be arranged between the tuning circuit 11 and the inductor, that is, the first end of the varactor 13 is respectively connected to the first end of the capacitor and the first end of the tuning circuit 11, and the second end of the varactor 13 is connected to the first end of the inductor. Alternatively, the varactor 13 can also be arranged at the second end of the inductor, that is, the first end of the varactor 13 is connected to the second end of the inductor, and the second end of the varactor 13 is connected to the second end of the capacitor. The above-mentioned varactor 13 can be a silicon carbide varactor, a silicon varactor, a gallium arsenide varactor, an indium gallium phosphide varactor, etc.

[0124] The input end of the controller 14 is connected to the output end of the receiving coil 15, and the output end of the controller 14 is connected to the input end of the tuning circuit 11. After receiving the reception signal of the receiving coil 15, when the controller 14 determines that the field strength of the transmission field of the transmitting coil is uneven, it sends a control signal to the varactor diode 13, and achieves the purpose of adjusting the field strength of the transmitting coil by changing the capacitance of the varactor diode 13.

[0125] The detuning circuit of the above-mentioned receiving coil includes a tuning circuit and a parallel resonant circuit, the parallel resonant circuit includes a varactor, the input end of the tuning circuit is connected to the output end of the controller, the output end of the tuning circuit is connected to the first end of the parallel resonant circuit, and the second end of the parallel resonant circuit is connected to the receiving coil; the varactor is arranged at one end of the parallel resonant circuit away from the receiving coil; the controller is used to send a control signal to the varactor according to the receiving signal of the receiving coil; the control signal is used to adjust the detuning frequency of the receiving coil to adjust the field strength of the transmitting coil. In this circuit, by setting the varactor in the parallel resonant circuit, the controller accurately controls the capacitance of the varactor through the receiving signal of the receiving coil to change the frequency of the parallel resonant circuit, thereby changing the detuning frequency of the receiving coil, and then achieving the purpose of adjusting the field strength of the transmitting coil.

[0126] In one embodiment, Fig.15 As shown, a parallel resonant circuit is provided. The parallel resonant circuit 12 includes a resonant inductor L, a resonant capacitor C, a diode group 121 and a first inductor L1. The first end of the resonant inductor L is respectively connected to the output end of the tuning circuit 11, the second end of the resonant inductor L is connected to the first end of the varactor diode 13, the second end of the varactor diode 13 is respectively connected to the first end of the first inductor L1 and the first end of the diode group 121, and the second end of the first inductor L1 and the second end of the diode group 121 are both connected to the second end of the resonant capacitor C.

[0127] Among them, the inductor in the parallel resonant circuit 12 is a resonant inductor, the capacitor is a resonant capacitor, and the resonant inductor is connected in parallel with the resonant capacitor. The diode group 121 is connected between the second end of the resonant inductor L and the second end of the resonant capacitor C. The diode group 121 includes two diodes, so the two diodes are connected in parallel between the second end of the resonant inductor L and the second end of the resonant capacitor C. The two diodes are set in opposite directions. The input end of the first diode is connected to the second end of the resonant inductor L, and the output end of the first diode is connected to the second end of the resonant capacitor C; the input end of the second diode is connected to the second end of the resonant capacitor C, and the output end of the second diode is connected to the second end of the resonant inductor L. The first inductor is the same as the diode group, and both are connected between the second end of the resonant inductor L and the second end of the resonant capacitor C, that is, the first inductor and the diode group are connected in parallel.

[0128] The parallel resonant circuit includes a resonant inductor, a resonant capacitor, a diode group and a first inductor, wherein the first end of the resonant inductor is respectively connected to the output end of the tuning circuit, the second end of the resonant inductor is connected to the first end of the varactor diode, the second end of the varactor diode is respectively connected to the first end of the first inductor and the first end of the diode group, and the second end of the first inductor and the second end of the diode group are both connected to the second end of the resonant capacitor. The circuit can accurately adjust the frequency of the parallel resonant circuit based on the received signal sent by the controller by arranging the varactor diode between the second end of the resonant inductor and the first end of the diode group.

[0129] In one embodiment, Fig.16 As shown, a tuning circuit is provided, which includes a second inductor L2, a third inductor L3 and a capacitor C1, the first end of the second inductor L2 is connected to the output end of the controller 14, the second end of the second inductor L2 is respectively connected to the first end of the third inductor L3 and the first end of the capacitor C1, the second end of the third inductor L3 is connected to the first end of the parallel resonant capacitor 12, and the second end of the capacitor C1 is grounded.

[0130] In this embodiment, since the output end of the controller 14 is connected to the input end of the tuning circuit 11, the signal received by the input end of the tuning circuit 11 is a DC signal. The receiving coil 15 is subjected to the magnetic flux cutting of the magnetic field emitted by the transmitting coil, and the current generated is an AC current, and the corresponding voltage is an AC voltage. Therefore, it is necessary to set a capacitor and an inductor on the tuning circuit 11. Based on the characteristics that the inductor passes DC and blocks AC and the capacitor passes AC and blocks DC, the control signal sent by the controller 14 can change the capacitance value of the varactor diode 13 through the second inductor L2, the third inductor L3 and the resonant inductor L.

[0131] The above tuning circuit includes a third inductor, a fourth inductor and a capacitor, the first end of the third inductor is connected to the output end of the controller, the second end of the third inductor is connected to the first end of the fourth inductor and the first end of the capacitor respectively, the second end of the fourth inductor is connected to the first end of the parallel resonant capacitor, and the second end of the capacitor is grounded. By setting the inductor and the capacitor, the tuning circuit can distinguish between the DC signal and the AC signal, so as to accurately control the capacitance value of the varactor diode.

[0132] Fig.17 The circuit diagram of the receiving coil shows the detuning circuit of the receiving coil. Fig.16 The circuit is the same as in, the difference is that an impedance matching circuit and a signal amplifier are also set between the receiving coil and the controller. The impedance matching circuit is used to transmit the receiving signal of the receiving coil to the controller more accurately, and the signal amplifier is used to amplify the receiving signal of the receiving coil.

[0133] In one embodiment, a magnetic resonance device is also provided. Fig.18 is a schematic diagram of the structure of a magnetic resonance device. The detuning circuit of the receiving coil in the magnetic resonance device is shown in the above Figure 14-17 The detuning circuit of the receiving coil is applied to a magnetic resonance device. When the magnetic resonance device is scanning an object, the influence of the field strength of the receiving coil on the field strength of the transmitting coil can be adjusted by detuning the frequency of the receiving coil. In this way, the transmitting coil can emit a more uniform field strength, thereby making the quality of the obtained magnetic resonance image higher.

[0134] Understandably, Fig.19 and Fig. 20 The schematic diagram is a structural diagram of a magnetic resonance device including two receiving coils. A detuning circuit of the two receiving coils can be set in the magnetic resonance device. The controller can adjust the detuning frequency of the two receiving coils to adjust the field strength of the target field strength area of ​​the two transmitting coils. Fig.21 Signal field strength distribution diagram for controlling the detuning circuit of the two receiving coils. Different gray scales in the diagram also represent different field strengths.

[0135] Based on the same inventive concept, the embodiment of the present application also provides a field intensity adjustment device for a transmitting field for implementing the field intensity adjustment method for a transmitting field involved above. The implementation scheme for solving the problem provided by the device is similar to the implementation scheme recorded in the above method, so the specific limitations in the embodiments of the field intensity adjustment device for one or more transmitting fields provided below can refer to the limitations of the field intensity adjustment method for a transmitting field above, and will not be repeated here.

[0136] In one embodiment, Fig. 22 As shown, a field intensity adjustment device for a transmitting field is provided, comprising: an acquisition module 11, a determination module 12 and a sending module 13, wherein:

[0137] An acquisition module 11 is used to acquire a reception signal of a receiving coil when the transmitting coil excites a target imaging area with a signal;

[0138] A determination module 12 is used to determine the field strength uniformity of the transmitting field of the transmitting coil according to the received signal;

[0139] The sending module 13 is used to send a control signal to the detuning circuit of the receiving coil according to the received signal when the field strength of the transmitting field is uneven. The control signal is used to adjust the detuning frequency of the receiving coil to adjust the field strength of the transmitting coil.

[0140] In one embodiment, the above-mentioned determination module includes: a generation unit and a determination unit, wherein:

[0141] A generating unit, used for generating a signal field strength distribution diagram according to a received signal;

[0142] The determination unit is used to determine the field intensity uniformity of the transmitting field of the transmitting coil according to the signal field intensity distribution diagram.

[0143] In one embodiment, the above-mentioned judgment unit is also used to determine that the field strength of the transmitting field of the transmitting coil is uneven when the number of changes in the field strength level in the area directly below the center position of the receiving coil in the signal field strength distribution diagram is greater than or equal to a preset number of times; and to determine that the field strength of the transmitting field of the transmitting coil is uniform when the number of changes in the field strength level in the area directly below the center position of the receiving coil in the signal field strength distribution diagram is less than a preset number of times.

[0144] In one embodiment, the sending module includes a first determining unit, a second determining unit, a third determining unit and a sending unit, wherein:

[0145] A first determining unit, configured to determine a uniform quantized value of field intensity of a transmitting field of the transmitting coil according to a received signal;

[0146] A second determining unit, configured to determine a detuning frequency adjustment value according to a difference between a uniform quantized value of field intensity of a transmitting field and a uniform quantized value of target field intensity;

[0147] A third determining unit, configured to determine a voltage adjustment value according to a capacitance adjustment value corresponding to the detuned frequency adjustment value;

[0148] The sending unit is used to send a voltage control signal to the varactor diode according to the voltage adjustment value.

[0149] Each module in the field intensity adjustment device of the above-mentioned transmitting field can be implemented in whole or in part by software, hardware and a combination thereof. Each of the above-mentioned modules can be embedded in or independent of the processor in the controller in the form of hardware, or can be stored in the memory in the controller in the form of software, so that the processor can call and execute the corresponding operations of each of the above modules.

[0150] In one embodiment, a controller is provided, including a memory and a processor, wherein a computer program is stored in the memory, and when the processor executes the computer program, the content of any one of the embodiments of the method for adjusting the field intensity of a transmitting field in the first aspect described above is implemented.

[0151] In one embodiment, a computer-readable storage medium is provided, on which a computer program is stored. When the computer program is executed by a processor, the content of any embodiment of the method for adjusting the field intensity of a transmitting field in the first aspect described above is implemented.

[0152] In one embodiment, a computer program product is provided, including a computer program, which, when executed by a processor, implements the content of any one of the embodiments of the method for adjusting the field intensity of a transmission field in the first aspect described above.

[0153] It should be noted that the user information (including but not limited to user device information, user personal information, etc.) and data (including but not limited to data used for analysis, stored data, displayed data, etc.) involved in this application are all information and data authorized by the user or fully authorized by all parties.

[0154] Those skilled in the art can understand that all or part of the processes in the above-mentioned embodiment methods can be completed by instructing the relevant hardware through a computer program, and the computer program can be stored in a non-volatile computer-readable storage medium. When the computer program is executed, it can include the processes of the embodiments of the above-mentioned methods. Among them, any reference to the memory, database or other medium used in the embodiments provided in the present application can include at least one of non-volatile and volatile memory. Non-volatile memory can include read-only memory (ROM), magnetic tape, floppy disk, flash memory, optical memory, high-density embedded non-volatile memory, resistive random access memory (ReRAM), magnetoresistive random access memory (MRAM), ferroelectric random access memory (FRAM), phase change memory (PCM), graphene memory, etc. Volatile memory can include random access memory (RAM) or external cache memory, etc. As an illustration and not limitation, RAM can be in various forms, such as static random access memory (SRAM) or dynamic random access memory (DRAM). The database involved in each embodiment provided in this application may include at least one of a relational database and a non-relational database. Non-relational databases may include distributed databases based on blockchains, etc., but are not limited to this. The processor involved in each embodiment provided in this application may be a general-purpose processor, a central processing unit, a graphics processor, a digital signal processor, a programmable logic device, a data processing logic device based on quantum computing, etc., but are not limited to this.

[0155] The technical features of the above embodiments may be combined arbitrarily. To make the description concise, not all possible combinations of the technical features in the above embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this specification.

[0156] The above embodiments only express several implementation methods of the present application, and the descriptions thereof are relatively specific and detailed, but they cannot be understood as limiting the scope of the present application. It should be pointed out that, for a person of ordinary skill in the art, several variations and improvements can be made without departing from the concept of the present application, and these all belong to the protection scope of the present application. Therefore, the protection scope of the present application shall be subject to the attached claims.

Claims

1. A method for adjusting the field intensity of a transmitting field, characterized in that: The method comprises: When the transmitting coil excites the target imaging area with a signal, a receiving signal of the receiving coil is obtained; Determining the field strength uniformity of the transmitting field of the transmitting coil according to the received signal; If the field strength of the transmitting field is uneven, a control signal is sent to the detuning circuit of the receiving coil according to the receiving signal; the control signal is used to adjust the detuning frequency of the receiving coil to adjust the field strength of the transmitting coil.

2. The method according to claim 1, characterized in that The determining, according to the received signal, the uniformity of the field intensity of the transmitting field of the transmitting coil comprises: generating a signal field strength distribution diagram according to the received signal; The field intensity uniformity of the transmitting field of the transmitting coil is determined according to the signal field intensity distribution diagram.

3. The method according to claim 2, characterized in that The determining, according to the signal field strength distribution diagram, the field strength uniformity of the transmitting field of the transmitting coil comprises: If the number of changes in the field intensity level in the area directly below the center position of the receiving coil in the signal field intensity distribution diagram is greater than or equal to a preset number, it is determined that the field intensity of the transmitting field of the transmitting coil is uneven; If, in the signal field strength distribution diagram, the number of field strength level changes in the area directly below the center position of the receiving coil is less than a preset number, it is determined that the field strength of the transmitting field of the transmitting coil is uniform.

4. The method according to any one of claims 1 to 3, characterized in that The detuning circuit includes a varactor diode, and sending a control signal to the detuning circuit of the receiving coil according to the received signal includes: Determining a uniform quantized value of field intensity of a transmitting field of the transmitting coil according to the received signal; Determining a detuning frequency adjustment value according to a difference between a uniform quantized value of field intensity of the transmitting field and a uniform quantized value of target field intensity; Determining a voltage adjustment value according to a capacitance adjustment value corresponding to the detuned frequency adjustment value; A voltage control signal is sent to the varactor diode according to the voltage adjustment value.

5. A detuning circuit (10) for a receiving coil, characterized in that: The detuning circuit (10) comprises a tuning circuit (11) and a parallel resonant circuit (12); the parallel resonant circuit (12) comprises a varactor (13); an input end of the tuning circuit (11) is connected to an output end of a controller (14); an output end of the tuning circuit (11) is connected to a first end of the parallel resonant circuit (12); and a second end of the parallel resonant circuit (12) is connected to the receiving coil (15); the varactor (13) is arranged at an end of the parallel resonant circuit (12) that is away from the receiving coil (15); The controller (14) is used to send a control signal to the varactor diode (13) according to a reception signal of the receiving coil (15); the control signal is used to adjust the detuning frequency of the receiving coil (15) to adjust the field strength of the transmitting coil.

6. The circuit according to claim 5, characterized in that The parallel resonant circuit (12) comprises a resonant inductor (L), a resonant capacitor (C), a diode group (121) and a first inductor (L1); the first end of the resonant inductor (L) is connected to the output end of the tuning circuit (11); the second end of the resonant inductor (L) is connected to the first end of the variable capacitance diode (13); the second end of the variable capacitance diode (13) is respectively connected to the first end of the first inductor (L1) and the first end of the diode group (121); the second end of the first inductor (L1) and the second end of the diode group (121) are both connected to the second end of the resonant capacitor (C).

7. The circuit according to claim 5, characterized in that The tuning circuit (11) comprises a second inductor (L2), a third inductor (L3) and a capacitor (C1); the first end of the second inductor (L2) is connected to the output end of the controller (14); the second end of the second inductor (L2) is respectively connected to the first end of the third inductor (L3) and the first end of the capacitor (C1); the second end of the third inductor (L3) is connected to the first end of the parallel resonant capacitor (12); and the second end of the capacitor (C1) is grounded.

8. A magnetic resonance device, characterized in that: The magnetic resonance device comprises a detuning circuit (10) for a receiving coil as claimed in any one of claims 5 to 7.

9. A field intensity adjustment device for a transmitting field, characterized in that: The device comprises: An acquisition module, used for acquiring a reception signal of a receiving coil when the transmitting coil excites a target imaging area with a signal; A determination module, used for determining the field strength uniformity of the transmission field of the transmitting coil according to the received signal; The sending module is used to send a control signal to the detuning circuit of the receiving coil according to the receiving signal when the field strength of the transmitting field is uneven, and the control signal is used to adjust the detuning frequency of the receiving coil to adjust the field strength of the transmitting coil.

10. A computer-readable storage medium having a computer program stored thereon, characterized in that: When the computer program is executed by a processor, the steps of the method according to any one of claims 1 to 4 are implemented.

Images