Magnetic particle imaging signal processing link and method based on adjustable external compensation

Abstract

The invention discloses a magnetic particle imaging signal processing link and method based on adjustable external compensation, and the link is characterized in that a signal generator is respectively connected with the input ends of a first power amplifier and a second power amplifier through a first output end and a second output end, the output end of the first power amplifier is connected with the input end of a first capacitor, and the output end of the second power amplifier is connected with the input end of a second capacitor; the output end of the first capacitor is connected with the input end of the receiving excitation module, the output end of the second power amplifier is connected with the input end of the second capacitor, the output end of the second capacitor is connected with the input end of the compensation excitation module, and the output ends of the receiving excitation module and the compensation excitation module are connected with the input end of the low-noise amplifier. The output end of the low-noise amplifier is connected with the input end of the acquisition card, the output end of the acquisition card is connected with the input end of the central processing unit, and the output end of the central processing unit is connected with the input end of the signal generator. According to the invention, the sensitivity and the imaging quality of the MPI equipment are obviously improved.

Description

Technical Field

[0001] The invention belongs to the technical field of magnetic particle imaging, and relates to a magnetic particle imaging signal processing link and method based on adjustable external compensation. Background Art

[0002] Magnetic Particle Imaging (MPI) is an imaging technology based on the spatial distribution of superparamagnetic iron oxide nanoparticles (SPIONs). It has significant advantages such as high spatiotemporal resolution, high sensitivity, no ionizing radiation, and quantitative detection. MPI has shown broad application prospects in the medical field, especially in angiography, cancer imaging, in vivo cell tracking, and inflammation imaging. However, in order to successfully apply MPI technology in clinical practice, it is necessary to further improve the sensitivity, spatiotemporal resolution, and imaging field of view of existing detection equipment to meet the higher requirements of clinical diagnosis and treatment.

[0003] Sensitivity is crucial for accurate imaging and early lesion detection, especially in clinical applications such as angiography and cancer imaging, which can effectively improve the accuracy of diagnosis and the ability to detect diseases early. At the same time, the imaging field of the MPI device is mainly limited by the aperture size of the receiving coil. However, the sensitivity of the receiving coil is inversely proportional to the aperture size. When the aperture increases, the sensitivity of the coil will decrease accordingly, affecting the details and accuracy of the imaging. Therefore, in order to improve the performance of the MPI device, optimizing sensitivity becomes a crucial goal. The improvement in sensitivity not only helps to improve imaging quality, but also solves the key challenge of applying MPI technology to human body size, providing more accurate and efficient tools for clinical medical imaging. Summary of the invention

[0004] In order to solve the above problems existing in the prior art, the present invention provides a magnetic particle imaging signal processing link and method based on adjustable external compensation. The technical problem to be solved by the present invention is achieved through the following technical solutions:

[0005] The present invention provides a magnetic particle imaging signal processing link based on adjustable external compensation, comprising:

[0006] A signal generator, used to generate a receiving excitation signal and a compensating excitation signal, wherein the receiving excitation signal is outputted from a first output terminal of the signal generator, and the compensating excitation signal is outputted from a second output terminal of the signal generator;

[0007] a first power amplifier, wherein an input end of the first power amplifier is connected to a first output end of the signal generator;

[0008] a first capacitor, wherein an input end of the first capacitor is connected to an output end of the first power amplifier;

[0009] A receiving excitation module, wherein an input end of the receiving excitation module is connected to an output end of the first capacitor;

[0010] a second power amplifier, wherein an input end of the second power amplifier is connected to a second output end of the signal generator;

[0011] a second capacitor, wherein an input end of the second capacitor is connected to an output end of the second power amplifier;

[0012] A compensation excitation module, wherein an input end of the compensation excitation module is connected to an output end of the second capacitor;

[0013] A low noise amplifier, the input end of the low noise amplifier is connected to the output ends of the excitation receiving module and the excitation compensation module;

[0014] An acquisition card, wherein an input end of the acquisition card is connected to an output end of the low noise amplifier;

[0015] A central processing unit, wherein the input end of the central processing unit is connected to the output end of the acquisition card, and the output end of the central processing unit is connected to the input end of the signal generator.

[0016] In one embodiment of the present invention, the excitation receiving module includes a receiving excitation coil and a receiving coil, the receiving coil is used to detect particle signals, and the receiving coil is nested in the receiving excitation coil.

[0017] In one embodiment of the present invention, the excitation compensation module includes a compensation excitation coil and a compensation coil, the compensation coil is used to detect equipment noise and generate a reverse coupling interference signal, and the compensation coil is nested in the compensation excitation coil; the compensation coil is connected in series with the receiving coil.

[0018] In one embodiment of the present invention, the compensation coil is coaxially arranged with the receiving coil.

[0019] In one embodiment of the present invention, the compensation excitation coil and the receiving excitation coil are coaxially arranged, the receiving excitation coil is located in the magnetic field, and the compensation excitation coil is far away from the magnetic field.

[0020] The present invention also provides a magnetic particle imaging signal processing method based on adjustable external compensation, which is implemented by the magnetic particle imaging signal processing link based on adjustable external compensation, and includes:

[0021] S1, a signal generator generates a receiving excitation signal and a compensation excitation signal;

[0022] S2, the receiving excitation signal is transmitted to the receiving excitation module through the first power amplifier and the first capacitor, and the compensating excitation signal is transmitted to the compensating excitation module through the second power amplifier and the second capacitor;

[0023] S3, placing the particles into the receiving excitation module, and performing signal subtraction between the receiving excitation module and the compensation excitation module;

[0024] S4. The subtracted signal is transmitted to the input end of the acquisition card through a low noise amplifier, and is transmitted from the output end of the acquisition card to the input end of the central processing unit. The central processing unit processes the collected signal and transmits it from the output end of the central processing unit to the input end of the signal generator.

[0025] In one embodiment of the present invention, the step S2 further includes:

[0026] The received excitation signal is transmitted from the first output end of the signal generator to the input end of the first power amplifier, and the first power amplifier processes the received excitation signal;

[0027] The received excitation signal processed by the first power amplifier is transmitted from the output end of the first power amplifier to the input end of the first capacitor, and then transmitted from the output end of the first capacitor to the excitation receiving module;

[0028] The compensation excitation signal is transmitted from the second output end of the signal generator to the input end of the second power amplifier, and the second power amplifier processes the compensation excitation signal;

[0029] The compensation excitation signal processed by the second power amplifier is transmitted from the output end of the second power amplifier to the input end of the second capacitor, and then transmitted from the output end of the second capacitor to the compensation excitation module.

[0030] In one embodiment of the present invention, the step S3 further includes:

[0031] The excitation receiving module includes a receiving excitation coil and a receiving coil, wherein the receiving coil is used to detect particle signals, and the receiving coil is nested in the receiving excitation coil;

[0032] The excitation compensation module includes a compensation excitation coil and a compensation coil, the compensation coil is used to detect equipment noise and generate a reverse coupling interference signal, and the compensation coil is nested in the compensation excitation coil;

[0033] The compensation coil is connected in series with the receiving coil to achieve signal subtraction at both ends.

[0034] In one embodiment of the present invention, the signal collected by the receiving coil is expressed as:

[0035]

[0036] Among them, U P represents the particle signal collected by the receiving coil, U noi1 represents the system noise collected by the receiving coil, ω is a known quantity, A1 is the amplitude of the coupled interference signal of the receiving coil, is the phase of the coupled interference signal of the receiving coil, and t is the time;

[0037] The signal collected by the compensation coil is expressed as:

[0038]

[0039] Among them, U noi2 represents the system noise collected by the compensation coil, A2 is the amplitude of the coupled interference signal of the compensation coil, is the phase of the coupled interference signal of the compensation coil, and t is the time;

[0040] The signal after the acquisition card collects and offsets is expressed as:

[0041]

[0042] Beneficial effects of the present invention:

[0043] The magnetic particle imaging signal processing link and method based on adjustable external compensation of the present invention construct a complete receiving and excitation link with high sensitivity and high adaptability by adopting a flexibly adjustable separate external compensation coil; at the same time, fine-tuning is performed in combination with a controllable signal input source, which can effectively suppress the background noise in the MPI device and the coupling interference between coils, thereby improving the quality and accuracy of the imaging signal; using completely identical receiving coils and compensation coils, the background noise in the space can be synchronously collected, and the sensitivity of the imaging device can be improved to a certain extent by means of series cancellation, solving the problem of insufficient sensitivity of some devices; using an external compensation structure as a receiving coil, which is not affected by the magnetic field, solves the problem that the permanent magnet MPI device is not suitable for the MPS device. BRIEF DESCRIPTION OF THE DRAWINGS

[0044] Figure 1 A circuit block diagram of a magnetic particle imaging signal processing link based on adjustable external compensation provided by an embodiment of the present invention;

[0045] Figure 2 A schematic diagram of the structure of a receiving excitation module and a compensation excitation module provided in an embodiment of the present invention;

[0046] Figure 3A flowchart of a magnetic particle imaging signal processing method based on adjustable external compensation is provided in an embodiment of the present invention.

[0047] In the figure: 1. receiving excitation module, 11. receiving excitation coil, 12. receiving coil, 2. compensation excitation module, 21. compensation excitation coil. DETAILED DESCRIPTION

[0048] The present invention will be described in detail below with reference to the accompanying drawings and specific embodiments, but the embodiments of the present invention are not limited thereto.

[0049] Embodiment 1:

[0050] The purpose of this embodiment is to provide a magnetic particle imaging signal processing link based on adjustable external compensation, and to optimize the magnetic particle imaging signal processing link by using a flexible and adjustable compensation strategy to improve the sensitivity of the MPI magnetic particle imaging device.

[0051] The present embodiment is based on a magnetic particle imaging signal processing link with adjustable external compensation, comprising: a signal generator, a first power amplifier, a first capacitor, a second power amplifier, a second capacitor, a receiving excitation module, a compensation excitation module, a low noise amplifier, an acquisition card and a central processing unit.

[0052] The signal generator is used to generate a receiving excitation signal and a compensating excitation signal. The receiving excitation signal is output from the first output terminal of the signal generator, and the compensating excitation signal is output from the second output terminal of the signal generator. The first output terminal and the second output terminal of the signal generator have the same frequency and the same initial phase. The signal generator is connected to the central processor and realizes precise adjustment of amplitude and phase through the control protocol.

[0053] The input end of the first power amplifier is connected to the first output end of the signal generator; the first capacitor, the input end of the first capacitor is connected to the output end of the first power amplifier; the second power amplifier, the input end of the second power amplifier is connected to the second output end of the signal generator; the second capacitor, the input end of the second capacitor is connected to the output end of the second power amplifier.

[0054] The receiving excitation module is used to generate a high-frequency excitation magnetic field, and the input end of the receiving excitation module is connected to the output end of the first capacitor; the compensation excitation module is used to generate an electromagnetic coupling signal, and the input end of the compensation excitation module is connected to the output end of the second capacitor.

[0055] The receiving excitation module is connected to the first capacitor to form a resonant circuit, which reduces the load of the entire circuit and reduces the power consumption of the excitation end, and is used to generate a high-frequency excitation magnetic field. The compensation excitation module is connected to the second capacitor to form a resonant circuit, which reduces the load of the entire circuit and reduces the power consumption of the excitation end, and is used to generate an opposite electromagnetic coupling signal. The receiving excitation module is located in the magnetic field, and the compensation excitation module is far away from the magnetic field to avoid mutual interference between the magnetic field and the excitation signal.

[0056] The low noise amplifier is used to amplify the voltage signal offset during the experiment, suppress the background noise, make the subsequent signal processing more accurate, and improve the signal-to-noise ratio of the equipment. The input end of the low noise amplifier is connected to the excitation receiving module and the excitation compensation module.

[0057] The acquisition card is used to acquire voltage signals. The acquisition port has four ports to collect different signals. The input end of the acquisition card is connected to the output end of the low-noise amplifier, and the signal output end of the acquisition card is used to interact with the central processing unit.

[0058] The central processing unit, the input end of the central processing unit is electrically connected to the output end of the acquisition card, and the output end of the central processing unit is connected to the input end of the signal generator, which is used to control the signal generator, realize accurate control of the signal generator, and realize accurate cancellation of noise and coupling signals. The signal collected by the acquisition card is processed to realize the reconstruction of the magnetic particle imaging technology (MPI) signal.

[0059] In an embodiment of the present invention, the excitation receiving module includes a receiving excitation coil and a receiving coil, the receiving coil is used to detect particle signals, and the receiving coil is nested in the receiving excitation coil. The excitation compensation module includes a compensation excitation coil and a compensation coil, the compensation coil is used to detect device noise and generate a reverse coupling interference signal, and the compensation coil is nested in the compensation excitation coil; the compensation coil is connected in series with the receiving coil, and the subtraction of the signals at both ends is achieved through a series circuit, that is, the interference signal is offset by the signal of the compensation coil, thereby effectively reducing the background noise received by the device. The compensation coil is coaxially arranged with the receiving coil, and the compensation excitation coil is coaxially arranged with the receiving excitation coil, to ensure that the background noise detected by the receiving compensation coil is as consistent as possible with the coupling interference signal. The receiving excitation coil is located in the magnetic field, and the compensation excitation coil is away from the magnetic field.

[0060] This embodiment proposes to adopt a separate external compensation strategy, by separating the traditional excitation receiving link into two parts (receiving excitation module and compensation excitation module), and extending the position of the compensation excitation module outside the magnetic field area, so as to effectively avoid the interference of the magnetic field on the compensation excitation module. This strategy can more accurately control the signal sensed by the compensation coil. This embodiment uses an acquisition device to detect the feedthrough interference of the device in real time, and can synchronously adjust the compensation effect when the electromagnetic conversion efficiency of the receiving coil changes, suppressing signal fluctuations during the scanning process, thereby significantly improving the sensitivity and imaging quality of the MPI device.

[0061] Furthermore, the separate external compensation coil proposed in this embodiment can collect noise signals in space in real time, and the direction is opposite to the signal collected in the receiving coil and the amplitude is similar. By connecting the two in series, the external compensation coil can effectively offset the background noise in space and maintain a high degree of real-time performance. This method not only improves the accuracy of noise suppression, but also ensures the stability of the device in complex environments, significantly improving the sensitivity and imaging quality of the MPI device.

[0062] In addition, in this embodiment, when the existing MPI equipment that uses permanent magnets to generate zero magnetic field areas tests the effectiveness of magnetic nanoparticles, it is usually necessary to first locate the position of the zero magnetic field area, or use an additional magnetic nanoparticle spectrometer (MPS, Magnetic Particle Spectroscopy) device to test the effectiveness of the particles, which increases the time cost and equipment cost of the test. The separate external compensation strategy proposed in this embodiment effectively solves this defect. The external compensation coil in this strategy can be used as a simple MPS device because it is not affected by the magnetic field. In the MPI device, this method does not require the location of the zero magnetic field area, nor does it require the use of additional MPS equipment for particle effectiveness testing, thereby making full use of the characteristics of the equipment and significantly reducing the time cost and equipment cost of testing the effectiveness of magnetic nanoparticles.

[0063] Embodiment 2:

[0064] The magnetic particle imaging signal processing method based on adjustable external compensation in this embodiment is implemented by the magnetic particle imaging signal processing link based on adjustable external compensation in Embodiment 1. Figure 3 The magnetic particle imaging signal processing method based on adjustable external compensation comprises:

[0065] S1, a signal generator generates a receiving excitation signal and a compensation excitation signal;

[0066] S2, the received excitation signal is transmitted to the received excitation module through the first power amplifier and the first capacitor, and the compensation excitation signal is transmitted to the compensation excitation module through the second power amplifier and the second capacitor;

[0067] S3, placing the particles into a receiving excitation module, and performing signal subtraction between the receiving excitation module and the compensation excitation module;

[0068] S4. The subtracted signal is transmitted to the input end of the acquisition card through the low noise amplifier, and is transmitted from the output end of the acquisition card to the input end of the central processing unit. The central processing unit processes the collected signal and transmits it from the output end of the central processing unit to the input end of the signal generator.

[0069] The magnetic particle imaging signal processing method based on adjustable external compensation in this embodiment mainly controls the external compensation excitation module to accurately change the electromagnetic coupling effect of the compensation coil, thereby solving the problem of poor compensation effect; and all processes from acquisition to signal regulation are controlled by C++ from the central processing unit, while ensuring the control accuracy and real-time performance of the control, and realizing the interaction of control and acquisition.

[0070] Specifically, step S2 also includes:

[0071] The receiving excitation signal is transmitted from the first output end of the signal generator to the input end of the first power amplifier, and the first power amplifier processes the receiving excitation signal; the receiving excitation signal processed by the first power amplifier is transmitted from the output end of the first power amplifier to the input end of the first capacitor, and then transmitted from the output end of the first capacitor to the excitation receiving module to generate a high-frequency excitation magnetic field; the compensation excitation signal is transmitted from the second output end of the signal generator to the input end of the second power amplifier, and the second power amplifier processes the compensation excitation signal; the compensation excitation signal processed by the second power amplifier is transmitted from the output end of the second power amplifier to the input end of the second capacitor, and then transmitted from the output end of the second capacitor to the compensation excitation module to generate an electromagnetic coupling signal.

[0072] In an embodiment of the present invention, step S3 further includes:

[0073] The excitation receiving module includes a receiving excitation coil and a receiving coil. The receiving coil is used to detect particle signals, and the receiving coil is nested in the receiving excitation coil. The excitation compensation module includes a compensation excitation coil and a compensation coil. The compensation coil is used to detect equipment noise and generate reverse coupling interference signals, and the compensation coil is nested in the compensation excitation coil. A compensation signal with the same size and a phase difference of 180 degrees is generated in the compensation coil. The receiving signal and the compensation signal are superimposed on each other to obtain a relatively pure background signal. The compensation coil is connected in series with the receiving coil to achieve signal subtraction at both ends.

[0074] The particles are placed in the receiving coil, and the signal collected by the receiving coil is expressed as:

[0075]

[0076] Among them, U P represents the particle signal collected by the receiving coil, U noi1 represents the system noise collected by the receiving coil, including but not limited to the thermal noise of the detection coil, the quantization noise of the analog-to-digital converter (ADC), and the electromagnetic interference in the environment. Since the frequency of the feedthrough interference is consistent with the excitation frequency, ω is a known quantity. A1 is the amplitude of the coupled interference signal of the receiving coil, is the phase of the coupled interference signal of the receiving coil, and t is the time;

[0077] The signal collected by the compensation coil is expressed as:

[0078]

[0079] Among them, U noi2 It represents the system noise collected by the compensation coil, including but not limited to the thermal noise of the compensation coil, the quantization noise of the analog-to-digital converter (ADC), and the electromagnetic interference in the environment. A2 is the amplitude of the coupled interference signal of the compensation coil, is the phase of the coupled interference signal of the compensation coil, and t is the time;

[0080] The signal after the acquisition card collects and offsets is expressed as:

[0081]

[0082] Due to the existence of irrational factors such as the position difference of the receiving coil and the compensation coil and the phase change caused by different power amplifiers, it is necessary to further adjust the amplitude and phase of the compensation excitation signal to achieve accurate cancellation of electromagnetic coupling. MPI imaging mainly relies on the movement of the zero magnetic field point (area) to obtain the spatial distribution of superparamagnetic nanoparticles. With the movement of the zero magnetic field point, the magnetic field distribution in the receiving coil also changes accordingly, and the inductance and electromagnetic conversion efficiency of the receiving coil also change accordingly, resulting in the feedthrough interference of the device changing during the MPI scanning process, that is, the device is unstable during the scanning process. This embodiment solves this problem by real-time acquisition of the feedthrough interference in the device to achieve accurate control of the compensation excitation coil. During the scanning process, the amplitude of the input signal is changed in real time to further change the electromagnetic coupling signal in the compensation coil to achieve the change, and achieve accurate suppression of the feedthrough interference. The above operations are all performed in the central processing unit, and real-time acquisition and real-time control are achieved through high-performance C++ programming.

[0083] So far, this embodiment has achieved the attenuation of feedthrough interference and obtained the complete particle signal including the fundamental frequency component.

[0084] The method of this embodiment can adaptively adjust the compensation signal according to different operating environments and application scenarios, and can also effectively suppress noise interference caused by factors such as equipment vibration and temperature changes, ensure the stability of the equipment in complex environments and high-quality imaging, and further improve the signal quality and sensitivity of the system. While achieving efficient attenuation of feedthrough interference, this method can retain the fundamental frequency component of the particle signal and avoid signal loss. By improving the signal-to-noise ratio of the collected signal, the sensitivity of the MPI device can be further improved, providing support for more accurate imaging. Moreover, the signal collected by this method has a rich number of harmonics, carries a large amount of information, and has good signal integrity. Combining it with the X-SPACE algorithm can further optimize the image processing effect, while avoiding the loss of feature information, providing higher convenience and accuracy for subsequent image optimization operations.

[0085] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. All contents that do not deviate from the technical solution of the present invention should be included in the protection scope of the present invention.

Claims

1. A magnetic particle imaging signal processing link based on adjustable external compensation, characterized in that: include: A signal generator, used to generate a receiving excitation signal and a compensating excitation signal, wherein the receiving excitation signal is outputted from a first output terminal of the signal generator, and the compensating excitation signal is outputted from a second output terminal of the signal generator; a first power amplifier, wherein an input end of the first power amplifier is connected to a first output end of the signal generator; a first capacitor, wherein an input end of the first capacitor is connected to an output end of the first power amplifier; A receiving excitation module, wherein an input end of the receiving excitation module is connected to an output end of the first capacitor; a second power amplifier, wherein an input end of the second power amplifier is connected to a second output end of the signal generator; a second capacitor, wherein an input end of the second capacitor is connected to an output end of the second power amplifier; A compensation excitation module, wherein an input end of the compensation excitation module is connected to an output end of the second capacitor; A low noise amplifier, the input end of the low noise amplifier is connected to the output ends of the excitation receiving module and the excitation compensation module; An acquisition card, wherein an input end of the acquisition card is connected to an output end of the low noise amplifier; A central processing unit, wherein the input end of the central processing unit is connected to the output end of the acquisition card, and the output end of the central processing unit is connected to the input end of the signal generator.

2. A magnetic particle imaging signal processing link based on adjustable external compensation according to claim 1, characterized in that: The excitation receiving module comprises a receiving excitation coil and a receiving coil. The receiving coil is used to detect particle signals, and the receiving coil is nested in the receiving excitation coil.

3. A magnetic particle imaging signal processing link based on adjustable external compensation according to claim 2, characterized in that: The excitation compensation module includes a compensation excitation coil and a compensation coil, the compensation coil is used to detect equipment noise and generate a reverse coupling interference signal, and the compensation coil is nested in the compensation excitation coil; The compensation coil is connected in series with the receiving coil.

4. A magnetic particle imaging signal processing link based on adjustable external compensation according to claim 3, characterized in that: The compensation coil is coaxially arranged with the receiving coil.

5. A magnetic particle imaging signal processing link based on adjustable external compensation according to claim 4, characterized in that: The compensation excitation coil is coaxially arranged with the receiving excitation coil. The receiving excitation coil is located in the magnetic field, and the compensation excitation coil is far away from the magnetic field.

6. A magnetic particle imaging signal processing method based on adjustable external compensation, characterized in that: The method is implemented by a magnetic particle imaging signal processing link based on adjustable external compensation as described in any one of claims 1 to 5, comprising: S1, a signal generator generates a receiving excitation signal and a compensation excitation signal; S2, the receiving excitation signal is transmitted to the receiving excitation module through the first power amplifier and the first capacitor, and the compensating excitation signal is transmitted to the compensating excitation module through the second power amplifier and the second capacitor; S3, placing the particles into the receiving excitation module, and performing signal subtraction between the receiving excitation module and the compensation excitation module; S4. The subtracted signal is transmitted to the input end of the acquisition card through a low noise amplifier, and is transmitted from the output end of the acquisition card to the input end of the central processing unit. The central processing unit processes the collected signal and transmits it from the output end of the central processing unit to the input end of the signal generator.

7. A magnetic particle imaging signal processing method based on adjustable external compensation according to claim 6, characterized in that: The S2 step further includes: The received excitation signal is transmitted from the first output end of the signal generator to the input end of the first power amplifier, and the first power amplifier processes the received excitation signal; The received excitation signal processed by the first power amplifier is transmitted from the output end of the first power amplifier to the input end of the first capacitor, and then transmitted from the output end of the first capacitor to the excitation receiving module; The compensation excitation signal is transmitted from the second output end of the signal generator to the input end of the second power amplifier, and the second power amplifier processes the compensation excitation signal; The compensation excitation signal processed by the second power amplifier is transmitted from the output end of the second power amplifier to the input end of the second capacitor, and then transmitted from the output end of the second capacitor to the compensation excitation module.

8. The method for processing magnetic particle imaging signals based on adjustable external compensation according to claim 7, characterized in that: The S3 step further includes: The excitation receiving module includes a receiving excitation coil and a receiving coil, wherein the receiving coil is used to detect particle signals, and the receiving coil is nested in the receiving excitation coil; The excitation compensation module includes a compensation excitation coil and a compensation coil, the compensation coil is used to detect equipment noise and generate a reverse coupling interference signal, and the compensation coil is nested in the compensation excitation coil; The compensation coil is connected in series with the receiving coil to achieve signal subtraction at both ends.

9. The method for processing magnetic particle imaging signals based on adjustable external compensation according to claim 8, characterized in that: The signal collected by the receiving coil is expressed as: Among them, U P represents the particle signal collected by the receiving coil, U noi1 represents the system noise collected by the receiving coil, ω is a known quantity, A1 is the amplitude of the coupled interference signal of the receiving coil, is the phase of the coupled interference signal of the receiving coil, and t is the time; The signal collected by the compensation coil is expressed as: Among them, U noi2 represents the system noise collected by the compensation coil, A2 is the amplitude of the coupled interference signal of the compensation coil, is the phase of the coupled interference signal of the compensation coil, and t is the time; The signal after the acquisition card collects and offsets is expressed as:

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