Application Cases

With the rapid advancement of nanotechnology in recent years, nanomaterials with unique optical, acoustic, electrical, and magnetic properties are increasingly used for the specific identification of tumor markers. These materials effectively enhance the sensitivity and accuracy of various imaging techniques in cancer diagnosis, providing critical reference points for the precise diagnosis of liver cancer. However, the integration of nanotechnology with ultrasound elastography remains largely unexplored. This study investigates a novel approach based on ultrasound-electromagnetic coupling elastography using magnetic nanoparticles. The method leverages magnetically induced vibrations of nanoparticles under pulsed magnetic fields, generating shear waves in the surrounding tissue. By detecting these vibrations and shear wave propagation via ultrasound, the distribution of magnetic nanoparticles and the elastic properties of the tissue can be determined.

In ultrasound-electromagnetic coupling elastography experiments involving magnetic nanoparticles, the ATA-3000 series power amplifier, combined with an arbitrary waveform function generator and excitation coils, forms the excitation signal source module. It amplifies signals within the 0–100 kHz frequency range. Its application effectiveness is demonstrated by amplifying the excitation signal by 20 dB to drive the coil, generating a pulsed magnetic field that effectively excites vibrations in the magnetic nanoparticles. This process, combined with the Verasonics ultrasound imaging system, enables the detection of particle vibrations and shear wave propagation. By adjusting the magnetic field strength (e.g., increasing it to 300 mT), the signal-to-noise ratio of vibration signals is improved, extending shear wave propagation distance. Even at a detection depth of 7 cm, the shear wave velocity can be effectively evaluated, providing critical support for the excitation of magnetically induced vibrations and the accuracy of elastography in experiments.

Experimental Name: Ultrasound-Electromagnetic Coupling Elastography Experiment

Experimental Principle:
In ultrasound-electromagnetic coupling elastography experiments, the excitation module drives magnetic nanoparticle vibrations through a chain reaction of "electrical signal generation → amplification → magnetic field conversion." A function generator produces electrical signals of specific waveforms, which are appropriately amplified by a power amplifier and then fed into the excitation coil. The coil converts the electrical signals into a pulsed magnetic field, inducing magnetically driven vibrations in the nanoparticles and exciting shear waves in the surrounding tissue. The power amplifier serves as a critical node for signal amplification, ensuring the excitation coil receives a driving current of sufficient strength to generate a pulsed magnetic field that meets experimental requirements (e.g., 300 mT). This provides the necessary excitation conditions for effective nanoparticle vibrations and subsequent ultrasound detection of shear waves. Through cross-physical field coupling (electrical → magnetic → acoustic), this process indirectly captures tissue elasticity information. The application of the power amplifier ensures the energy output of the excitation signal, serving as a vital link between electrical signals and magnetic field excitation, thereby supporting the triggering of magnetically induced vibrations and the excitation of shear wave propagation.

Experimental Block Diagram:

Experimental Setup Photo:

Experimental Procedure:
In ultrasound-electromagnetic coupling elastography experiments, an arbitrary waveform generator is configured to emit Gaussian pulses. These pulses are amplified by 20 dB using a power amplifier, and the amplified signal is fed into an excitation coil to generate a pulsed magnetic field. This, in turn, drives the magnetic nanoparticles to vibrate. Simultaneously with the emission of excitation pulses, the ultrasound acquisition system transmits plane waves to detect the vibrations of the nanoparticles. A Verasonics Vantage 128 system and a Philips L7-4 linear array probe (center frequency: 5 MHz) are employed, with a repetition frequency of 10 kHz, five compound angles, and an effective detection frequency of 2 kHz. The experiment captures 100 frames of images, corresponding to an acquisition time of 50 ms. Under the influence of the pulsed magnetic field, magnetic nanoparticles in the phantom vibrate, and an ultrafast plane-wave ultrasound acquisition system collects the pulse-echo signals. A two-dimensional autocorrelation algorithm is then used to calculate the vibration displacement of the nanoparticles and derive the shear wave velocity. Based on the relationship between shear wave velocity and shear modulus, the mechanical properties of the region can be determined.

Application Fields:
Early and precise diagnosis of liver cancer, comprehensive assessment of liver diseases, medical device processing, expansion of targeted elastography techniques

Application Scenarios:
Ultrasound-electromagnetic coupling elastography, magnetic nanoparticles, magnetically induced vibrations, targeted elastography, ex vivo/in vivo detection

Recommended Product:ATA-3000 Series Power Amplifier

Figure: ATA-300/3000 Series Power Amplifier Specifications and Parameters

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