Microbubble destruction by dual-high-frequency ultrasound excitation

Yeh, Chih‐Kuang; Su, Shin-Yuan; Shen, Che-Chou

doi:10.1109/tuffc.2009.1145

Cited by 11 publications

(12 citation statements)

References 20 publications

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“…A small frequency difference means the long beating period. The pressure threshold for microbubble destruction by the long pulses was found to become lower at a small frequency difference [20]. Additional effects, such as heating and rectified diffusion, may become prominent after the exposure of the long pulses and alter the medium or the nuclei population.…”

Section: Discussionmentioning

confidence: 92%

“…Two high driving frequencies around the resonant frequency of the transducer could be applied to one transducer using the magnetic signal coupling [19]. The nonlinear oscillation and destruction of microbubbles can be effectively enhanced by the low-frequency envelope (their frequency difference) [20]. Thus, the pressure threshold for microbubble destruction becomes lower, which saved almost 30% power in order to achieve the same thrombolysis efficiency [21,22].…”

Section: Introductionmentioning

confidence: 99%

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Cavitation histotripsy at the surface of soft material using the dual-frequency excitation

Zhou,

Lei

2020

Eng. Res. Express

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Cavitation histotripsy has been applied for the disintegration at the interface of soft tissue and fluid in a well-controlled manner. The dual-frequency excitation was proposed and evaluated in this study. The acoustic field generated by the dual-frequency (1.09+1.11 MHZ) excitation and associated bubble dynamics at the focus was simulated using Khokhlov-Zabolotskaya-Kuznetsov equation and Gilmore model, respectively, and compared with those by the single-frequency (1.1 MHz) excitation at the same power. Their beam sizes and distribution of pulse-average acoustic intensity are similar. It shows that the dual-frequency excitation at the duty cycle of 2% and pulse repetition frequency of 1 Hz after 20 s exposure can increase the erosion area and volume on the surface of Alginate gel phantom by ∼2 fold (p<0.05). The effects of operating parameters of the cavitation histotripsy with the dualfrequency excitation on the erosion were investigated. Small frequency difference (< 0.1 MHz), high modulation depth (100%), moderate pulse repetition frequency (100 Hz), large duty cycle, and long interval time between pulses are preferred. Meanwhile, the acoustic emission signals during the ultrasound exposure were collected using passive cavitation detection to calculate their spectra using the short-time Fourier transform. It is shown that higher scattering and inertial cavitation levels, especially at small frequency differences and high modulation depth can be produced by the dualfrequency excitation. Erosion capabilities of both excitations were also evaluated using the ex vivo porcine kidney.

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Section: Discussionmentioning

confidence: 92%

Section: Introductionmentioning

confidence: 99%

Cavitation histotripsy at the surface of soft material using the dual-frequency excitation

Zhou,

Lei

2020

Eng. Res. Express

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“…Our previous study also demonstrated that microbubble destruction is more efficient for the DF excitation method than for a conventional single-frequency method (Yeh et al 2009). For potential applications of DF excitation with the coded excitation method, a higher axial resolution of contrast imaging, while maintaining the impinging insonation energy, can help us to increase the capability of depth penetration in high-frequency microbubbles for a destruction/replenishment imaging system.…”

Section: Discussion and Concluding Remarksmentioning

confidence: 92%

Dual-frequency chirp imaging for contrast detection

2011

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The method of dual-frequency (DF) difference excitation is capable of generating a low-frequency envelope component as the driving force of commercial contrast microbubbles by using a high-frequency pulse. Although the DF difference excitation method provides good lateral resolution in high-frequency contrast imaging, it suffers from degraded axial resolution because a longer-than-usual envelope component is required to induce the oscillation of microbubbles. In this study, a coded excitation technique (i.e. chirp waveform) is combined with the DF difference excitation method (also referred to as the DF chirp excitation method) to improve the axial resolution of contrast imaging while maintaining the impinging insonation energy. B-mode images were constructed to compare the performance of the DF chirp excitation method with the conventional tone-burst pulse method. Results indicate that the proposed DF chirp excitation method can provide better axial resolution after pulse compression. Moreover, as compared to the tone-burst pulse with the same pulse duration, the pulse compression results in a higher signal-to-noise ratio because of the temporal concentration of the received energy. Nevertheless, images with the DF chirp excitation method demonstrated noticeable image artefacts resulting from the range sidelobes. The DF chirp excitation method also produced obvious tissue harmonic generation that could degrade the contrast-to-tissue ratio at higher acoustic pressures.

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“…It should be noted that the period number of lower frequency is used for the dual-frequency case, similar to the previous study (Wang et al 2021). Actually, the amplitude of dualfrequency ultrasound is modulated by the two single-frequency components (Yeh et al 2009, Guédra et al 2017, Law and Zhou 2018, Suo et al 2018, Zhou and Lei 2020, thus the dual-frequency driving is still periodic and its period can be calculated as the method described in the previous study (Hegedűs et al 2020). In our simulations, the calculations were performed during five periods of the dual-frequency ultrasound.…”

Section: Comparation Of Bubble Dynamics Under Single-and Dual-frequen...mentioning

confidence: 92%

“…Note that the larger the peak negative acoustic pressure is, the larger the bubble expansion becomes. For the same energy input, the peak negative acoustic pressure dual-frequency ultrasound could be larger than that of each single-frequency ultrasound ( P PNP ∆ > 0), which is conducive to enhance the bubble cavitation and its associated bio-effects (Yeh et al 2009, Hegedűs et al 2020. Therefore, the frequency ratio and the phase difference between the two components can be reasonably chosen to maximize the peak negative acoustic pressure of the resultant dual-frequency ultrasound, thereby achieving an obvious enhancement of the bubble dynamics.…”

Section: Influence Of Frequency Ratio and Phase Differencementioning

confidence: 99%

Enhancing cavitation dynamics and its mechanical effects with dual-frequency ultrasound

Zou

Qin

2022

Phys. Med. Biol.

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Objective. Acoustic cavitation and its mechanical effects (e.g., stress and strain) play a primary role in ultrasound applications. Introducing encapsulated microbubbles as cavitation nuclei and utilizing dual-frequency ultrasound excitation are highly effective approaches to reduce cavitation thresholds and enhance cavitation effects. However, the cavitation dynamics of encapsulated microbubbles and the resultant stress/strain in viscoelastic tissues under dual-frequency excitation are poorly understood, especially for the enhancement effects caused by a dual-frequency approach. The goal of this study was to numerically investigate the dynamics of a lipid-coated microbubble and the spatiotemporal distributions of the stress and strain under dual-frequency excitation. Approach. The Gilmore-Zener bubble model was coupled with a shell model for the nonlinear changes of both shell elasticity and viscosity to accurately simulate the cavitation dynamics of lipid-coated microbubbles in viscoelastic tissues. Then, the spatiotemporal evolutions of the cavitation-induced stress and strain in the surrounding tissues were characterized quantitatively. Finally, the influences of some paramount parameters were examined to optimize the outcomes. Main results. We demonstrated that the cavitation dynamics and associated stress/strain were prominently enhanced by a dual-frequency excitation, highlighting positive correlations between the maximum bubble expansion and the maximum stress/strain. Moreover, the results showed that the dual-frequency ultrasound with smaller differences in its frequencies and pressure amplitudes could enhance the bubble oscillations and stress/strain more efficiently, whereas the phase difference manifested small influences under these conditions. Additionally, the dual-frequency approach seemed to show a stronger enhancement effect with the shell/tissue viscoelasticity increasing to a certain extent. Significance. This study might contribute to optimizing the dual-frequency operation in terms of cavitation dynamics and its mechanical effects for high-efficient ultrasound applications.

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Microbubble destruction by dual-high-frequency ultrasound excitation

Cited by 11 publications

References 20 publications

Cavitation histotripsy at the surface of soft material using the dual-frequency excitation

Cavitation histotripsy at the surface of soft material using the dual-frequency excitation

Dual-frequency chirp imaging for contrast detection

Enhancing cavitation dynamics and its mechanical effects with dual-frequency ultrasound

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