Self-adaptive compensation control system for magnetic particle imaging and use method of self-adaptive compensation control system

Abstract

The invention belongs to the technical field of signal processing. The invention provides a self-adaptive compensation control system for magnetic particle imaging and a use method of the self-adaptive compensation control system. According to the embodiment of the invention, the phase of the compensation signal can be adaptively, quickly and accurately adjusted according to the actual attenuation degree of the feed-through interference, and phase deviation between the compensation signal and the feed-through interference caused by irrational factors such as limited conversion rate of the DAC and signal propagation path delay is avoided. Moreover, the phase information of the compensation signal does not need to be acquired through repeated iteration, thereby improving the attenuation effect and stability, and simplifying the compensation process. On the basis of realizing high attenuation for feed-through interference, the fundamental component of the particle signal can be reserved, and the signal-to-noise ratio of the acquired signal and the sensitivity of the MPI equipment are improved. The system integrates the functions of signal generation, data acquisition and transmission and adaptive compensation. The whole MPI equipment works in the same clock domain, the system stability is improved, the complexity of hardware equipment is reduced, and the method is suitable for most MPI equipment.

Description

Technical Field

[0001] Embodiments of the present disclosure relate to the technical field of signal processing, and in particular, to an adaptive compensation control system for magnetic particle imaging and a method of using the same. Background Art

[0002] Magnetic Particle Imaging (MPI) technology can image the spatial distribution of superparamagnetic iron oxide nanoparticles (SPIONs). Compared with other imaging technologies, MPI imaging has become a research hotspot in medical imaging technology because it integrates advantages such as high spatio-temporal resolution, high sensitivity, quantitative detection, and no ionizing radiation. With the continuous in-depth research, many emerging MPI device forms have gradually emerged. For example, FFL-MPI, unilateral MPI, traveling wave MPI, and MPI with the size of the human brain have been developed. The clinical application scenarios of MPI have also emerged continuously, and it has relatively extensive application research in the fields of tumor treatment, vascular imaging, targeted drug delivery, magnetic hyperthermia, etc., and can be integrated with other imaging modalities. With the continuous development of MPI device forms and medical application scenarios, higher requirements are put forward for parameters such as the sensitivity, spatio-temporal resolution, and imaging field of view of MPI devices. However, these parameters are in a mutually restrictive relationship. Sensitivity is the core index of MPI devices, which refers to the minimum number of particles that the device can detect. For MPI devices, an enlarged imaging field of view means an increased detection coil aperture, resulting in a significant weakening of the detected particle signal and a reduction in device sensitivity. At the same time, sensitivity and spatial resolution are usually interrelated. Spatial resolution refers to the minimum distance that can distinguish between imaging phantoms, which is directly related to the device gradient magnitude. An increase in the device gradient will improve the spatial resolution but will also bring the problem of a reduction in the number of particles that can respond, affecting the device sensitivity. In addition, increasing the data acquisition time can reduce the noise level, but this method sacrifices the time resolution of MPI devices. Therefore, in the face of diverse requirements, there are huge challenges in improving the sensitivity of MPI devices.

[0003] The sensitivity of the MPI device is directly related to the signal-to-noise ratio of the acquired signal. The sensitivity of the MPI device can be improved by increasing the signal strength and reducing the existing interference and noise to meet the diverse clinical medical needs. However, there is feedthrough interference caused by electromagnetic coupling in the MPI device, which is several orders of magnitude higher than the particle signal. Usually, analog filtering is used to filter it out. However, since the feedthrough interference has the same fundamental frequency component as the particle signal, the problem of the lack of the fundamental frequency component of the particle signal is brought about while filtering. As the frequency component with the largest energy proportion in the particle signal, the lack of the fundamental frequency component will lead to a decrease in the signal-to-noise ratio and limit the sensitivity of the MPI device. In the related technologies, none of them can attenuate the feedthrough interference and retain the fundamental frequency component of the particle signal.

[0004] Therefore, it is necessary to improve one or more problems existing in the above-mentioned related technical solutions.

[0005] It should be noted that this part aims to provide background or context for the technical solutions of the present disclosure stated in the claims. The description here is not admitted to be prior art just because it is included in this part. Summary of the Invention

[0006] The purpose of the embodiments of the present disclosure is to provide an adaptive compensation control system for magnetic particle imaging and its usage method, so as to overcome at least to some extent one or more problems caused by the limitations and defects of the related technologies.

[0007] According to the first aspect of the embodiments of the present disclosure, an adaptive compensation control system for magnetic particle imaging is provided. The system includes:

[0008] A communication control module, configured to receive a control instruction transmitted by a host computer, generate a corresponding control signal according to the control instruction, and transmit it to the signal generation module, the data acquisition and transmission module, and the adaptive compensation module respectively to implement overall working timing control;

[0009] A signal generation module, configured to generate excitation signal waveform data and drive signal waveform data and transmit them to the MPI device through a power amplifier, so that the MPI device can generate particle signals, feedthrough interference, excitation current signals, and drive current signals;

[0010] A first data acquisition and transmission module, configured to acquire the feedthrough interference passing through a differential low-noise amplifier and transmit the feedthrough interference to the adaptive compensation module;

[0011] An adaptive compensation module, configured to analyze the feedthrough interference, generate and output an adaptive compensation analog signal to perform differential processing with the particle signal through the differential low-noise amplifier to obtain a complete particle signal;

[0012] The second data acquisition and transmission module is used to acquire complete particle signals, excitation current signals, and drive current signals and transmit them to the host computer.

[0013] Furthermore, the system further includes:

[0014] The first DAC module, the second DAC device, the third DAC device, and the fourth DAC device; where

[0015] The first DAC module is used to generate excitation signal waveform data, convert the excitation signal waveform data into an excitation voltage signal, and transmit it to the MPI device through a power amplifier;

[0016] The second DAC device and the third DAC device are used to generate drive signal waveform data, convert the drive signal waveform data into a drive voltage signal, and transmit it to the MPI device through a power amplifier;

[0017] The fourth DAC device is used to generate an adaptive compensation analog signal in combination with the adaptive compensation module, convert the adaptive compensation data into an adaptive compensation signal, and transmit the adaptive compensation signal to the differential low-noise amplifier.

[0018] Furthermore, the system further includes:

[0019] The first ADC module, the second ADC device, the third ADC device, and the fourth ADC device; where

[0020] The first ADC module is used to acquire the excitation current signal and convert the excitation current signal into excitation current data;

[0021] The second ADC device and the third ADC device are used to acquire the drive current signal and convert the drive current signal into drive current data;

[0022] The fourth ADC device is used to acquire the feedthrough interference and the complete particle signal, transmit the feedthrough interference to the adaptive compensation module, and convert the complete particle signal into particle signal data.

[0023] Furthermore, the process of analyzing the feedthrough interference, generating and outputting an adaptive compensation analog signal to the differential low-noise amplifier for differential processing with the particle signal to obtain a complete particle signal includes:

[0024] When the excitation current signal and the drive current signal exist and the particle is not placed in the MPI device, set the gain multiple α of the differential low-noise amplifier to 1, and compensate the feedthrough interference through the differential low-noise amplifier to obtain the compensated feedthrough interference;

[0025] The adaptive compensation module collects the compensated feedthrough interference and the background noise of the MPI device to obtain a first acquisition signal; where the first acquisition signal is expressed as:

[0026]

[0027] In the formula, is the feedthrough interference, U N is the background noise of the MPI device, A E is the amplitude of the feedthrough interference, is the phase of the feedthrough interference, and t is the t-th moment;

[0028] According to the amplitude A E and the phase of the compensated feedthrough interference, a compensation signal is obtained; where the compensation signal is expressed as:

[0029]

[0030] In the formula, ΔT is the time delay of the compensation signal relative to the feedthrough interference, is the starting phase of the compensation signal, is the phase difference between the compensation signal and the feedthrough interference;

[0031] The compensation signal is input into a differential low-noise amplifier to attenuate the feedthrough interference to obtain a second acquisition signal; where the second acquisition signal is expressed as:

[0032]

[0033] The phase of the adaptive compensation signal is adjusted, and when the peak value V (U p ) of the differential feedthrough interference 2 is lower than or equal to the peak value V p (U N ) of the background noise of the MPI device, the attenuation degree of the feedthrough interference reaches the maximum, then stop adjusting the phase of the compensation signal and maintain a stable output in the current state, thereby completing the adaptive adjustment of the compensation signal to obtain a third acquisition signal, that is, the adaptive compensation signal; where the adaptive compensation signal is expressed as:

[0034] U 3 =U N (4)

[0035] After the attenuation is completed, the particles are placed into the MIP device and the gain multiple of the differential low-noise amplifier is adjusted to obtain a fourth acquisition signal; where the fourth acquisition signal is expressed as:

[0036] U 4 (t)=αU p (t)+UN1 (5)

[0037] Among them, α represents the gain multiple of the amplifier, and U p (t) represents the complete particle signal, and U N1 represents the amplified MPI system background noise.

[0038] According to the second aspect of the embodiments of the present disclosure, a method for using an adaptive compensation control system for magnetic particle imaging is provided. The method includes:

[0039] Electrically connect the MPI device to the signal generation module, the first data acquisition and transmission module, the second data acquisition and transmission module, and the adaptive compensation module respectively;

[0040] Use the signal generation module to generate excitation signal waveform data and drive signal waveform data and transmit them to the MPI device through a power amplifier;

[0041] Use the MPI device to generate an excitation current signal and a drive current signal without putting in particles to generate feedthrough interference;

[0042] Transmit the feedthrough interference to the adaptive compensation module through a differential amplifier for analysis, generate and output an adaptive compensation signal;

[0043] Put particles in the MPI device to generate a particle signal;

[0044] After transmitting the adaptive compensation signal and the particle signal to a differential low-noise amplifier, obtain a complete particle signal;

[0045] Use the second data acquisition and transmission module to collect the complete particle signal, the excitation current signal, and the drive current signal and transmit them to the host computer.

[0046] Furthermore, the method further includes:

[0047] Use the first DAC module to generate excitation signal waveform data, convert the excitation signal waveform data into an excitation voltage signal, and transmit it to the MPI device through a power amplifier;

[0048] Use the second DAC device and the third DAC device to generate drive signal waveform data, convert the drive signal waveform data into a drive voltage signal, and transmit it to the MPI device through a power amplifier;

[0049] Use the fourth DAC device to generate adaptive compensation data in combination with the adaptive compensation module and convert the adaptive compensation data into an adaptive compensation signal.

[0050] Furthermore, the method further includes:

[0051] The first ADC module is used to collect the excitation current signal and convert the excitation current signal into excitation current data;

[0052] The second ADC device and the third ADC device are used to collect the drive current signal and convert the drive current signal into drive current data;

[0053] The fourth ADC device is used to collect the feedthrough interference and the complete particle signal, transmit the feedthrough interference to the adaptive compensation module, and convert the complete particle signal into particle signal data.

[0054] Further, the method further includes:

[0055] The second data acquisition and transmission module is used to collect the particle signal data, the excitation current data and the drive current data and transmit them to the host computer.

[0056] The technical solutions provided by the embodiments of the present disclosure may include the following beneficial effects:

[0057] In the embodiments of the present disclosure, through the above-mentioned adaptive compensation control system for magnetic particle imaging and its usage method, on the one hand, the system can adaptively and quickly and accurately adjust the phase of the compensation signal according to the actual attenuation degree of the feedthrough interference, avoiding the phase shift between the compensation signal and the feedthrough interference caused by non-rational factors such as the limited DAC conversion rate and the signal propagation path delay, and there is no need to obtain the phase information of the compensation signal through multiple iterative acquisitions, improving the attenuation effect and stability and simplifying the compensation process. On the basis of achieving high attenuation of the feedthrough interference, the fundamental frequency component of the particle signal can be retained, improving the signal-to-noise ratio of the acquired signal and the sensitivity of the MPI device. On the other hand, the system integrates functions of signal generation, data acquisition and transmission, and adaptive compensation. It can make the entire MPI device work in the same clock domain, improving the system stability, reducing the complexity and cost of the hardware device, and being applicable to most MPI devices. BRIEF DESCRIPTION OF THE DRAWINGS

[0058] The accompanying drawings here are incorporated into the specification and constitute a part of this specification, showing embodiments consistent with the present disclosure and used together with the specification to explain the principles of the present disclosure. Obviously, the accompanying drawings in the following description are only some embodiments of the present disclosure, and those of ordinary skill in the art can also obtain other drawings based on these drawings without creative efforts.

[0059] Figure 1 A schematic diagram showing an adaptive compensation control system for magnetic particle imaging in an exemplary embodiment of the present disclosure;

[0060] Figure 2Schematic diagram of the signal link of an adaptive compensation control system for magnetic particle imaging in an exemplary embodiment of the present disclosure;

[0061] Figure 3 Schematic diagram of the circuit system of an adaptive compensation control system for magnetic particle imaging in an exemplary embodiment of the present disclosure;

[0062] Figure 4 Step diagram of a method of using an adaptive compensation control system for magnetic particle imaging in an exemplary embodiment of the present disclosure;

[0063] Figure 5 Schematic diagram of data acquisition under different methods in an exemplary embodiment of the present disclosure;

[0064] Figure 6 Comparison diagram of the spectral distribution of particle signals in an exemplary embodiment of the present disclosure;

[0065] Figure 7 Reconstructed image of the signal acquired by the analog filtering method in an exemplary embodiment of the present disclosure;

[0066] Figure 8 Reconstructed image of the signal acquired by the adaptive compensation method in an exemplary embodiment of the present disclosure. Detailed implementation manners

[0067] Example embodiments will now be described more fully with reference to the accompanying drawings. However, the example embodiments can be implemented in various forms and should not be construed as limited to the examples set forth herein; rather, these embodiments are provided so that this disclosure will be more complete and comprehensive, and will fully convey the concept of the example embodiments to those skilled in the art. The features, structures, or characteristics described may be combined in any suitable manner in one or more embodiments.

[0068] In addition, the accompanying drawings are only schematic illustrations of the embodiments of the present disclosure and are not necessarily drawn to scale. The same reference numerals in the drawings denote the same or similar parts, and thus their repeated description will be omitted. Some of the block diagrams shown in the drawings are functional entities and do not necessarily correspond to physically or logically independent entities.

[0069] In this example embodiment, an adaptive compensation control system for magnetic particle imaging is first provided. Referring to Figure 1 as shown in, the adaptive compensation control system for magnetic particle imaging may include:

[0070] A communication control module, configured to receive a control instruction transmitted by a host computer, generate a corresponding control signal according to the control instruction, and transmit the control signal to a signal generation module, a data acquisition and transmission module, and an adaptive compensation module respectively to implement overall working timing control;

[0071] A signal generation module for generating excitation signal waveform data and drive signal waveform data and transmitting them to an MPI device through a power amplifier, so that the MPI device can generate particle signals, feedthrough interference, excitation current signals, and drive current signals;

[0072] A first data acquisition and transmission module for acquiring feedthrough interference passing through a differential low-noise amplifier and transmitting the feedthrough interference to an adaptive compensation module;

[0073] An adaptive compensation module for analyzing the feedthrough interference, generating and outputting an adaptive compensation analog signal to perform differential processing with the particle signal by the differential low-noise amplifier to obtain a complete particle signal;

[0074] A second data acquisition and transmission module for acquiring the complete particle signal, excitation current signal, and drive current signal and transmitting them to a host computer.

[0075] With the above adaptive compensation control system for magnetic particle imaging, on the one hand, the system can quickly and accurately adjust the phase of the compensation signal adaptively according to the actual attenuation degree of the feedthrough interference, avoiding the phase shift between the compensation signal and the feedthrough interference caused by non-rational factors such as the limited DAC conversion rate and signal propagation path delay, and there is no need to obtain the phase information of the compensation signal through multiple iterative acquisitions, improving the attenuation effect and stability and simplifying the compensation process. On the basis of achieving high attenuation of the feedthrough interference, the fundamental frequency component of the particle signal can be retained, improving the signal-to-noise ratio of the acquired signal and the sensitivity of the MPI device. On the other hand, the system integrates functions of signal generation, data acquisition and transmission, and adaptive compensation. It can make the entire MPI device work in the same clock domain, improving the system stability, reducing the complexity and cost of hardware devices, and being applicable to most MPI devices.

[0076] Next, reference will be made to Figures 1 to 2 to describe each part of the above adaptive compensation control system for magnetic particle imaging in the exemplary embodiment in more detail.

[0077] In one embodiment, as Figure 1As shown in the figure, the proposed adaptive compensation control system for magnetic particle imaging in this application uses FPGA (Field Programmable Gate Array, FPGA) as the main controller, which is divided into a communication control module, a signal generation module, a data acquisition and transmission module, and an adaptive compensation module according to functions. The communication control module is used to receive the instructions transmitted by the host computer, and generate corresponding control signals according to the instructions and transmit them to other modules to achieve the overall working timing control. Its working timing can be divided into four stages: First, the signal generation module generates excitation and drive signals and transmits them to the MPI device through a power amplifier (Power Amplifier, PA) to generate excitation and drive magnetic fields. Second, the data acquisition and transmission module collects the feedthrough interference existing in the MPI device and transmits the collected data to the adaptive module. Subsequently, the adaptive compensation module analyzes the incoming data, generates and outputs a compensation signal and transmits it to the signal receiving link for adaptive compensation. After the adaptive compensation is completed, the data acquisition and transmission module collects the particle signal, excitation and drive current signals, and transmits the collected data to the PC (i.e., the host computer) for storage.

[0078] More specifically, the adaptive compensation control system for magnetic particle imaging uses FPGA (Field Programmable Gate Array, FPGA) as the main control unit, and includes multiple DAC devices (Digital to Analog Converter, DAC) and ADC devices (Analog to Digital Conver, ADC). Specifically, it includes a first analog voltage output terminal, a second analog voltage output terminal, a third analog voltage output terminal, a fourth analog voltage output terminal, a first analog voltage input terminal, a second analog voltage input terminal, a third analog voltage input terminal, a fourth analog voltage input terminal, an instruction input terminal, and a data output terminal. Among them, the first analog voltage output terminal is used to output an excitation voltage signal, the second and third analog voltage output terminals are used to output drive voltage signals, and the fourth analog voltage output terminal is used to output an adaptive compensation signal; the first analog voltage input terminal is used to receive an excitation current signal, the second and third analog voltage input terminals are used to output drive current signals, and the fourth analog voltage input terminal is used to receive the signal in the detection coil in the MPI device; the instruction input terminal and the data output terminal are used for data interaction with the PC.

[0079] A power amplifier, including an input end and an output end, the input ends of multiple power amplifiers are respectively connected to the first to third analog voltage output ends of an adaptive compensation control system for magnetic particle imaging. The positive voltage output ports are respectively connected to the excitation coil and the drive coil in the MPI device; the output current signals are respectively connected to the first to third analog voltage input ports of the adaptive compensation control system for magnetic particle imaging after being converted by Hall components.

[0080] A low-noise differential amplifier, including a positive input end, a negative input end and an output end, the positive input end of the preamplifier is electrically connected to the first end of the detection coil, and the second input end of the preamplifier is connected to the fourth analog voltage output port of the adaptive compensation system; its output end is connected to the fourth analog voltage input port of the adaptive compensation control system for magnetic particle imaging.

[0081] In addition, the MPI device includes:

[0082] A capacitor, including a first end and a second end, the first end of the capacitor is electrically connected to the output end of the power amplifier;

[0083] An excitation coil, including a first end and a second end, one end of the excitation coil is electrically connected to the second end of the capacitor, and the second end of the excitation coil is grounded; the excitation coil is used to generate a high-frequency excitation magnetic field;

[0084] A drive coil, including a first end and a second end, one end of the excitation coil is connected to the positive output port of the power amplifier, and the second end of the drive coil is grounded; the drive coil is used to generate a drive magnetic field;

[0085] A detection coil, including a first end and a second end, the first end of the detection coil is connected to the positive port of the low-noise differential amplifier, and the second end of the detection coil is grounded; the excitation coil and the detection coil are nested. Among them, the detection coil is a three-section gradient coil.

[0086] Furthermore, the PC end includes an instruction output end and a data input end, and the instruction output end and the data input end are connected to the instruction input end and the data output end of the adaptive compensation control system for magnetic particle imaging.

[0087] In a specific embodiment, the system further includes: a first DAC module, a second DAC device, a third DAC device and a fourth DAC device; among them,

[0088] The first DAC module is used to generate excitation signal waveform data, convert the excitation signal waveform data into an excitation voltage signal, and transmit it to the MPI device through a power amplifier;

[0089] The second DAC device and the third DAC device are used to generate driving signal waveform data, convert the driving signal waveform data into a driving voltage signal, and transmit it to the MPI device through a power amplifier;

[0090] The fourth DAC device is used to generate an adaptive compensation analog signal in combination with the adaptive compensation module, convert the adaptive compensation data into an adaptive compensation signal, and transmit the adaptive compensation signal to the differential low-noise amplifier.

[0091] In a specific embodiment, the system further includes: a first ADC module, a second ADC device, a third ADC device, and a fourth ADC device; wherein,

[0092] The first ADC module is used to receive the excitation current signal and convert the excitation current signal into excitation current data;

[0093] The second ADC device and the third ADC device are used to receive the driving current signal and convert the driving current signal into driving current data;

[0094] The fourth ADC device is used to receive the feedthrough interference after being compensated by the differential low-noise amplifier, and convert the compensated feedthrough interference into feedthrough interference data; and receive the particle signal and the adaptive compensation signal, process the particle signal and the adaptive compensation signal into a complete acquired particle signal, and convert it into particle signal data.

[0095] In a specific embodiment, as Figure 2 shown, it is a schematic diagram of the adaptive compensation signal link.

[0096] First, an excitation and driving voltage signal is generated and transmitted to the MPI device to generate a corresponding magnetic field, and the feedthrough interference is preliminarily attenuated through the gradient detection coil to prevent damage to the electronic devices in the signal link due to excessive interference. When the excitation and driving magnetic fields exist and the particles are not placed in the MPI device, the gain multiple α of the differential low-noise amplifier is set to 1, and the signal collected by the adaptive compensation unit can be expressed as:

[0097]

[0098] In the formula, is the feedthrough interference after passive compensation. U N represents the background noise of the MPI system, including the thermal noise of the detection coil, the quantization noise and thermal noise of the ADC device, etc. Since the frequency of the feedthrough interference is a known quantity. The adaptive compensation processing unit only needs to obtain the phase and amplitude A E , and use them as the amplitude A C (t) of the compensation signal U E and the starting phase

[0099] Due to the existence of non-ideal factors such as the limited DAC conversion rate and signal propagation path delay, the processing unit needs to further adjust the phase of the compensation signal. For cosine signals of the same frequency, the phase difference between signals can be converted into a time delay difference. Therefore, the time delay ΔT of the compensation signal relative to the feedthrough interference can be dynamically adjusted to achieve dynamic phase adjustment of the compensation signal. At this time, the compensation signal can be expressed as:

[0100]

[0101] The compensation signal is further input into the differential low-noise amplifier to attenuate the feedthrough interference. The signal collected at this time can be expressed as:

[0102]

[0103] During the process of adjusting the phase of the compensation signal, the attenuation degree of the feedthrough interference also changes accordingly. When it is detected that the peak value V p (U 2 ) is lower than or equal to the peak value V p (U N ) of the MPI system background noise, the feedthrough interference at this time can no longer be detected, and its attenuation degree can be considered to reach the maximum. At the same time, stop adjusting the phase of the compensation signal and maintain a stable output in the current state, so as to complete the adaptive adjustment of the compensation signal. The signal collected at this time can be expressed as:

[0104] U 3 =U N (4)

[0105] After the attenuation is completed, the particle is placed into the device and the gain multiple of the differential low-noise amplifier is adjusted. The signal collected at this time can be expressed as:

[0106] U 4 (t)=αU p (t)+U N1 (5)

[0107] Among them, α represents the gain multiple of the amplifier, U p (t) represents the complete particle signal including the fundamental frequency component, and U N1 represents the amplified MPI system background noise. And the collected data is transmitted to the host computer for storage. Thus, the attenuation of the feedthrough interference is achieved and the complete particle signal including the fundamental frequency component is obtained.

[0108] In a specific embodiment, the corresponding ADC and DAC device types are selected and the corresponding hardware circuit is built, as Figure 3 shown. Among them, as Figure 3(a) Schematic diagram of the system power supply module; as Figure 3 (b) Schematic diagram of the ADC_DAC peripheral circuit; as Figure 3 (c) Schematic diagram of the FPGA control board; as Figure 3 (d) Schematic diagram of the adaptive compensation control system for magnetic particle imaging.

[0109] In this exemplary embodiment, a method for using the adaptive compensation control system for magnetic particle imaging is also provided. Refer to Figure 4 As shown in

[0110] Step S101: Electrically connect the MPI device to the signal generation module, the first data acquisition and transmission module, the second data acquisition and transmission module, and the adaptive compensation module respectively;

[0111] Step S102: Use the signal generation module to generate excitation signal waveform data and drive signal waveform data, and transmit them to the MPI device through a power amplifier;

[0112] Step S103: Use the MPI device to generate an excitation current signal and a drive current signal without putting in particles to generate feedthrough interference;

[0113] Step S104: Compensate the feedthrough interference through a differential low-noise amplifier, and transmit the compensated feedthrough interference to the adaptive compensation module for analysis, generate and output an adaptive compensation signal;

[0114] Step S105: Put particles in the MPI device to generate particle signals;

[0115] Step S106: Transmit the adaptive compensation signal and the particle signal to the differential low-noise amplifier to obtain a complete particle signal;

[0116] Step S107: Use the second data acquisition and transmission module to collect the complete particle signal, the excitation current signal, and the drive current signal and transmit them to the host computer.

[0117] In one embodiment, the method further includes:

[0118] Use the first DAC module to generate excitation signal waveform data, convert the excitation signal waveform data into an excitation voltage signal, and transmit it to the MPI device through a power amplifier;

[0119] Use the second DAC device and the third DAC device to generate drive signal waveform data, convert the drive signal waveform data into a drive voltage signal, and transmit it to the MPI device through a power amplifier;

[0120] An adaptive compensation analog signal is generated by using a fourth DAC device in combination with an adaptive compensation module, and the adaptive compensation data is converted into an adaptive compensation signal.

[0121] In one embodiment, the method further includes:

[0122] Receiving an excitation current signal by using a first ADC module and converting the excitation current signal into excitation current data;

[0123] Receiving a drive current signal by using a second ADC device and a third ADC device and converting the drive current signal into drive current data;

[0124] Receiving the feedthrough interference after being compensated by a differential low-noise amplifier by using a fourth ADC device, and converting the compensated feedthrough interference into feedthrough interference data; and receiving a particle signal and an adaptive compensation signal, processing the particle signal and the adaptive compensation signal into a complete acquired particle signal, and converting it into particle signal data.

[0125] In one embodiment, the method further includes:

[0126] Collecting particle signal data, excitation current data, and drive current data by using a second data acquisition and transmission module and transmitting them to a host computer.

[0127] In a specific embodiment, to verify the effectiveness of the present application, relevant experiments were carried out. The reagent used in the experiment was a commercial magnetic nanoparticle The hydrodynamic diameter was 70 nm. The iron concentration of the reagent was the solid content (20 mg / ml), and it was filled into a cylindrical sample with an inner diameter of 3 mm for constant volume, and the volume was 150 μL. The particles were placed at the center of the imaging field of view. When the excitation magnetic field was 9.28 mT @ 25 kHz and the drive magnetic fields were 18 mT @ 1 Hz and 36 mT @ 50 Hz respectively, particle signal acquisition and empty signal acquisition (the signal acquired when the device was working and no particles were placed) were carried out through the adaptive compensation method and the analog filtering method respectively. The LNA gain was set to 500, and the total acquisition time was 10 s. For the analog filtering method, the analog filter used was a high-pass filter ZFHP-0R055-S+ from Mini-Circuit Company, and its passband range was from 0.07 MHz to 1000 MHz. Figure 5 A time-domain comparison diagram of the signals acquired by the two methods is shown. After calculation, as Figure 5 The signal-to-noise ratio of the signal acquired by the adaptive compensation method shown in (a) is 16.1522 dB, and as Figure 5 The signal-to-noise ratio of the analog filtering method shown in (b) is 1.2711 dB. Figure 6Shows the comparison diagram of the spectrum of the collected signals. Except for the fundamental frequency component, the amplitudes of the higher harmonics of the two methods are basically the same. Therefore, the adaptive compensation method can retain the fundamental frequency component of the particle signal, thereby improving the signal-to-noise ratio of the collected signal.

[0128] And further verify the effect of the adaptive compensation method on improving the sensitivity of the MPI device from the imaging perspective. The X-SPACE method was used to reconstruct the images of particle signals with different concentrations. The reconstructed images corresponding to the collected signals under the simulated filtering method and the adaptive compensation method are respectively as Figure 7 , Figure 8 shown. Since the position of the particles in the imaging device is known, the actual area where the particles are located in the device can be associated with the pixel area in the reconstructed image, so as to determine the position of the particles in the reconstructed image, as shown in the red box area in the figure. Among them, as Figure 7 (a) is the reconstructed image of the collected signal by the simulated filtering method when the concentration is 20 mg / ml; as Figure 7 (b) is the reconstructed image of the collected signal by the simulated filtering method when the concentration is 16 mg / ml; as Figure 7 (c) is the reconstructed image of the collected signal by the simulated filtering method when the concentration is 8 mg / ml; as Figure 7 (d) is the reconstructed image of the collected signal by the simulated filtering method when the concentration is 4 mg / ml; as Figure 7 (e) is the reconstructed image of the collected signal by the simulated filtering method when the concentration is 2 mg / ml; as Figure 7 (f) is the reconstructed image of the collected signal by the simulated filtering method when the concentration is 1 mg / ml; as Figure 7 (g) is the reconstructed image of the collected signal by the simulated filtering method when the concentration is 0.66 mg / ml; as Figure 7 (h) is the reconstructed image of the collected signal by the simulated filtering method when the concentration is 0.5 mg / ml. As Figure 8 (a) is the reconstructed image of the collected signal by the adaptive compensation method when the concentration is 20 mg / ml; as Figure 8 (b) is the reconstructed image of the collected signal by the adaptive compensation method when the concentration is 16 mg / ml; as Figure 8 (c) is the reconstructed image of the collected signal by the adaptive compensation method when the concentration is 8 mg / ml; as Figure 8 (d) is the reconstructed image of the collected signal by the adaptive compensation method when the concentration is 4 mg / ml; as Figure 8 (e) is the reconstructed image of the collected signal by the adaptive compensation method when the concentration is 2 mg / ml; as Figure 8 (f) is the reconstructed image of the collected signal by the adaptive compensation method when the concentration is 1 mg / ml; as Figure 8 (g) is the reconstructed image of the collected signal by the adaptive compensation method when the concentration is 0.66 mg / ml; as Figure 8(h) is the reconstructed image of the signal collected by the adaptive compensation method when the concentration is 0.5 mg / ml.

[0129] For the analog filtering method, when the concentration of the particle reagent is 1 mg / ml, since the signal-to-noise ratio of the collected signal is too low, the particle signal is submerged by noise and the particle image cannot be reconstructed normally. Under the analog filtering method, the minimum particle concentration that the MPI device can detect is 2 mg / ml (the volume of the particle reagent is 150 ul). For the adaptive compensation method proposed in this application, when the concentration of the particle reagent is also 1 mg / ml, the image can still be reconstructed normally due to the high signal-to-noise ratio. Until the concentration is 0.5 mg / ml, the particle image cannot be reconstructed normally. Under the adaptive compensation method, the minimum particle concentration that the MPI device can detect is 0.66 mg / ml (the volume of the particle reagent is 150 ul). It is verified that the adaptive compensation proposed in this application can improve the signal-to-noise ratio by retaining the fundamental frequency component, thereby improving the sensitivity of the MPI device. Compared with the analog filtering method, the sensitivity of the self-developed MPI device is increased by nearly three times.

[0130] Through the above-mentioned adaptive compensation control system for magnetic particle imaging and its usage method, on the one hand, the system can quickly and accurately adjust the phase of the compensation signal adaptively according to the actual attenuation degree of the feedthrough interference, avoiding the phase shift between the compensation signal and the feedthrough interference caused by non-rational factors such as the limited DAC conversion rate and the signal propagation path delay, and there is no need to obtain the phase information of the compensation signal through multiple iterative acquisitions, improving the attenuation effect and stability and simplifying the compensation process. On the basis of achieving high attenuation of the feedthrough interference, the fundamental frequency component of the particle signal can be retained, improving the signal-to-noise ratio of the collected signal and the sensitivity of the MPI device. On the other hand, the system integrates functions of signal generation, data acquisition and transmission, and adaptive compensation. It can make the entire MPI device work in the same clock domain, improving the system stability, reducing the complexity and cost of the hardware device, and being applicable to most MPI devices.

[0131] It should be understood that the orientation or positional relationship indicated by the terms "center", "longitudinal", "transverse", "length", "width", "thickness", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", "clockwise", "counterclockwise", etc. in the above description is based on the orientation or positional relationship shown in the drawings, and is only for the convenience of describing the embodiments of the present disclosure and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be construed as a limitation to the embodiments of the present disclosure.

[0132] In addition, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the quantity of the indicated technical features. Thus, features defined with "first" and "second" may explicitly or implicitly include one or more of such features. In the description of the embodiments of the present disclosure, the meaning of "a plurality of" is two or more unless otherwise specifically defined.

[0133] In the embodiments of the present disclosure, unless otherwise clearly defined and limited, terms such as "mounted", "connected", "coupled", "fixed", etc. shall be construed in a broad sense. For example, it may be a fixed connection, a detachable connection, or integrated; it may be a mechanical connection or an electrical connection; it may be directly connected or indirectly connected through an intermediate medium, and it may be the communication inside two elements or the interaction relationship between two elements. For those of ordinary skill in the art, the specific meanings of the above terms in the present disclosure may be understood according to specific circumstances.

[0134] In the embodiments of the present disclosure, unless otherwise clearly defined and limited, the first feature being "on" or "under" the second feature may include the direct contact between the first and second features, or may include the situation where the first and second features are not in direct contact but in contact through additional features therebetween. Moreover, the first feature being "above", "over" and "on top of" the second feature includes that the first feature is directly above and obliquely above the second feature, or merely means that the first feature is at a higher level than the second feature in terms of horizontal height. The first feature being "under", "beneath" and "underneath" the second feature includes that the first feature is directly below and obliquely below the second feature, or merely means that the first feature is at a lower level than the second feature in terms of horizontal height.

[0135] In the description of this specification, the descriptions referring to terms such as "one embodiment", "some embodiments", "example", "specific example" or "some examples", etc. mean that the specific features, structures, materials or characteristics described in connection with the embodiment or example are included in at least one embodiment or example of the present disclosure. In this specification, the schematic descriptions of the above terms do not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials or characteristics described may be combined in a suitable manner in any one or more embodiments or examples. In addition, those skilled in the art can combine and combine the different embodiments or examples described in this specification.

[0136] Other embodiments of the present disclosure will be readily apparent to those skilled in the art upon consideration of the specification and practice of the invention disclosed herein. This application is intended to cover any variations, uses, or adaptations of the present disclosure that follow the general principles of the present disclosure and include known common general knowledge or conventional technical means in the technical field not disclosed in the present disclosure. The specification and examples are only to be considered as exemplary, and the true scope and spirit of the present disclosure are pointed out by the appended claims.

Claims

1. An adaptive compensation control system for magnetic particle imaging, characterized in that: The system includes: The communication control module is used to receive the control instructions transmitted by the host computer, and generate corresponding control signals according to the control instructions, and transmit them to the signal generation module, the data acquisition and transmission module and the adaptive compensation module respectively, so as to realize the overall working timing control; A signal generating module, used for generating excitation signal waveform data and driving signal waveform data and transmitting them to the MPI device through a power amplifier, so that the MPI device can generate a particle signal, a feedthrough interference, an excitation current signal and a driving current signal; A first data acquisition and transmission module, used for acquiring feedthrough interference passing through the differential low noise amplifier, and transmitting the feedthrough interference to the adaptive compensation module; An adaptive compensation module is used to analyze the feedthrough interference, generate and output an adaptive compensation analog signal to a differential low-noise amplifier for differential processing with the particle signal to obtain a complete particle signal; The second data acquisition and transmission module is used to acquire complete particle signals, excitation current signals and drive current signals, and transmit them to the host computer.

2. The adaptive compensation control system for magnetic particle imaging according to claim 1, characterized in that: The system also includes: A first DAC module, a second DAC device, a third DAC device and a fourth DAC device; wherein, A first DAC module is used to generate excitation signal waveform data, convert the excitation signal waveform data into an excitation voltage signal, and transmit it to the MPI device through a power amplifier; The second DAC device and the third DAC device are used to generate driving signal waveform data, convert the driving signal waveform data into a driving voltage signal, and transmit it to the MPI device through a power amplifier; The fourth DAC device is used to generate an adaptive compensation analog signal in combination with the adaptive compensation module, convert the adaptive compensation analog signal into an adaptive compensation signal, and transmit the adaptive compensation signal to the differential low noise amplifier.

3. The adaptive compensation control system for magnetic particle imaging according to claim 2, characterized in that: The system also includes: A first ADC module, a second ADC device, a third ADC device and a fourth ADC device; wherein, A first ADC module is used to collect the excitation current signal and convert the excitation current signal into excitation current data; The second ADC device and the third ADC device are used to collect the driving current signal and convert the driving current signal into driving current data; The fourth ADC device is used to collect feedthrough interference and complete particle signals, transmit the feedthrough interference to the adaptive compensation module, and convert the complete particle signal into particle signal data.

4. The adaptive compensation control system for magnetic particle imaging according to claim 3, characterized in that: The process of analyzing the feedthrough interference, generating and outputting the adaptive compensation analog signal to the differential low noise amplifier for differential processing with the particle signal to obtain the complete particle signal includes: When the excitation current signal and the driving current signal exist and the particle is not placed in the MPI device, the differential low noise amplifier gain multiple α is set to 1, and the feedthrough interference is compensated by the differential low noise amplifier to obtain the compensated feedthrough interference; The adaptive compensation module collects the compensated feedthrough interference and the background noise of the MPI device to obtain a first acquisition signal; wherein the first acquisition signal is expressed as: In the formula, is the feedthrough interference, U N is the background noise of the MPI equipment, A E is the amplitude of the feedthrough interference, is the phase of feedthrough interference, t is the tth moment; According to the amplitude A of the compensated feedthrough interference E and Phase The compensation signal is obtained; wherein the compensation signal is expressed as: Where ΔT is the time delay of the compensation signal relative to the feedthrough interference, To compensate the starting phase of the signal, To compensate for the phase difference between the signal and the feedthrough interference; The compensation signal is input into the differential low noise amplifier to attenuate the feedthrough interference to obtain a second acquisition signal; wherein the second acquisition signal is expressed as: The phase of the adaptive compensation signal is adjusted, and when the feedthrough interference after differentiation The peak value V p (U2) is lower than or equal to the peak noise floor of the MPI device V p (U N ), the feedthrough interference attenuation degree reaches the maximum, then the phase adjustment of the compensation signal is stopped and the stable output in the current state is maintained, thereby completing the adaptive adjustment of the compensation signal to obtain the third acquisition signal, that is, the adaptive compensation signal; wherein the adaptive compensation signal is expressed as: U3=U N (4) After the attenuation is completed, the particle is placed in the MIP device and the gain multiple of the differential low noise amplifier is adjusted to obtain a fourth acquisition signal; wherein the fourth acquisition signal is expressed as: U4(t)=αU p (t)+U N1 (5) Among them, α represents the gain multiple of the amplifier, U p (t) represents the complete particle signal, U N1 Represents the amplified MPI system noise floor.

5. A method for using an adaptive compensation control system for magnetic particle imaging, characterized in that: The method includes: The MPI device is electrically connected to the signal generating module, the first data acquisition and transmission module, the second data acquisition and transmission module and the adaptive compensation module respectively; The signal generating module is used to generate excitation signal waveform data and driving signal waveform data and transmits them to the MPI device through the power amplifier; The excitation current signal and the driving current signal are generated in the MPI device without placing particles to generate feedthrough interference; The feedthrough interference is transmitted to the adaptive compensation module through the differential amplifier for analysis, and an adaptive compensation signal is generated and output; Placing particles in the MPI device to generate particle signals; After the adaptive compensation signal and the particle signal are transmitted to a differential low noise amplifier, a complete particle signal is obtained; The second data acquisition and transmission module is used to collect the complete particle signal, the excitation current signal and the drive current signal and transmit them to the host computer.

6. The method for using the adaptive compensation control system for magnetic particle imaging according to claim 5, characterized in that: The method further includes: Using the first DAC module to generate excitation signal waveform data, converting the excitation signal waveform data into an excitation voltage signal, and transmitting the excitation voltage signal to the MPI device through the power amplifier; Using the second DAC device and the third DAC device to generate driving signal waveform data, converting the driving signal waveform data into a driving voltage signal, and transmitting the driving voltage signal to the MPI device through the power amplifier; The fourth DAC device is combined with the adaptive compensation module to generate adaptive compensation data, and the adaptive compensation data is converted into an adaptive compensation signal.

7. The method for using the adaptive compensation control system for magnetic particle imaging according to claim 6, characterized in that: The method further includes: Using the first ADC module to collect the excitation current signal and convert the excitation current signal into excitation current data; Using the second ADC device and the third ADC device to collect the driving current signal, and convert the driving current signal into driving current data; The fourth ADC device is used to collect feedthrough interference and complete particle signals, and the feedthrough interference is transmitted to the adaptive compensation module to convert the complete particle signal into particle signal data.

8. The method for using the adaptive compensation control system for magnetic particle imaging according to claim 7, characterized in that: The method further includes: The second data acquisition and transmission module is used to collect particle signal data, excitation current data and drive current data and transmit them to the host computer.

Images