Yufeng Zhou

High-intensity focused ultrasound (HIFU) has emerged as a safe and effective tumor treatment modality, harnessing thermal effects to induce tissue coagulation, cavitation effects to cause liquefaction, or a synergistic combination of both mechanisms. As a widely adopted diagnostic tool, ultrasound imaging plays an integral role throughout the entire HIFU treatment continuum, encompassing tumor diagnosis, localization, procedural navigation, real-time intraprocedural monitoring, post-treatment outcomes evaluation, and long-term clinical follow-ups. This is attributed to its real-time imaging capability, low cost, non-ionizing nature, deep tissue penetration, and satisfactory resolution and sensitivity. Conventional B-mode sonography has been extensively employed for guiding HIFU treatment, yet it is constrained by notable technical limitations. To address these issues, a range of innovative ultrasound imaging approaches have been developed. A narrative review of the literature was conducted to systematically examine the functional roles and performance characteristics of these emerging techniques and to explore their potential for clinical translation as an integrated, multi-functional single system. Evidence demonstrates significant improvement of these novel ultrasound imaging technologies across various stages of HIFU treatment, particularly in temperature imaging and tissue characterization. With continued technological advancements and systematic integration, ultrasound imaging is poised to play an increasingly crucial role in optimizing the safety and efficacy of HIFU tumor treatment.

Diabetic wound infections remain highly refractory to treatment due to persistent bacterial colonization, oxidative stress, dysregulated inflammation, vasc

Focused ultrasound (FUS) offers a noninvasive therapeutic modality for cardiac conditions, yet its transthoracic application is impeded by the rib cage, which induces strong reflection and scattering, severely degrading the focusing performance of conventional phased arrays. Non-diffraction waves such as Airy beams possess self-bending and self-healing capabilities that enable propagation past obstructions, but their focal position remains fixed. To overcome these limitations, we proposed a hybrid phase-weighted beamforming strategy that integrates cubic Airy phase modulation with time-delayed wavefront focusing, enabling trajectory-controlled acoustic energy transport while preserving dynamic focus control. This method was evaluated numerically using a dual-elliptical rib model in full-wave simulations, with comprehensive comparisons against conventional phased array focusing in both free field and rib-obstructed configurations. Simulations show that the proposed Airy beam achieves 98.0% focal intensity retention behind ribs that is 28.3% higher than conventional focusing, reduces rib surface temperature rise by 22.2%, and maintains focal integrity over extensive lateral (x = ±20 mm) and axial (z = 40-100 mm) focus steering ranges. This work reveals a distinct beamforming paradigm based on trajectory control rather than focal phase compensation alone, suggesting that phase-weighted Airy beams provide a promising framework for safe, robust, and dynamically controllable transthoracic FUS therapy.

Acoustofluidics has emerged as a transformative technology for contact-free manipulation of microparticles and fluids in microscale systems. Although bulk acoustic waves (BAWs) are known to displace inhomogeneous fluids through acoustic radiation force acting at fluid interfaces, the capability of surface acoustic waves (SAWs) to produce analogous relocation phenomena remains largely unexplored. This study addresses a critical gap in acoustofluidic theory by presenting the first comprehensive finite element method investigation of SAW-driven motion of inhomogeneous fluid confined within microchannels of widths equal to one full or one-half SAW wavelength. Unlike BAW-based system that generate uniform pressure fields across channel heights, SAW devices exhibit inherently nonuniform vertical pressure distributions and intense near-boundary streaming—features that fundamentally alter fluid relocation dynamics. Our simulations demonstrate that despite high-frequency operation (6.65 MHz) and strong ARF, standing SAW fields fail to achieve stable fluid relocation in both initially stable and unstable configurations due to vertical pressure stratification and rapid floor-level streaming. Nevertheless, these same characteristics generate vigorous transverse folding flows that enable exceptionally rapid homogenization, offering a distinct acoustofluidic mechanism for on-chip mixing. These findings not only elucidate fundamental physical differences between BAW and SAW actuation in multiphase microfluidic systems but also establish design principles for SAW-induced microfluidic mixers. The results provide crucial theoretical guidance for device optimization where rapid homogenization is desired over stable stratification.

High-Intensity Focused Ultrasound (HIFU) is a potent treatment for solid tumors. The Energy Efficiency Factor (EEF), defined as the acoustic energy needed to ablate a unit volume of tissue, is pivotal for assessing HIFU's efficiency. However, determining the optimal transducer configuration and irradiation parameters remains challenging. A hybrid approach combining Machine Learning (ML) and Genetic Algorithm (GA) was utilized to minimize the EEF. Multi-Layer Perceptron (MLP), Radial Basis Function (RBF), and Extreme Gradient Boosting (XGB) models were employed to predict EEF across various HIFU transducer settings and irradiation conditions. The most accurate model was chosen for further refinement using GAs to identify minimal EEF values. The MLP model demonstrated superior performance in EEF prediction over RBF and XGB. The MLP-GA model effectively determined the optimal parameters for HIFU ablation, achieving minimal EEF values of 0.68 J/mm³ for continuous wave and 0.70 J/mm³ for pulsed wave modes. The differences between the MLP-GA model's findings and those of a traditional grid search were approximately 3.0%. The integrated ML-GA approach is effective for optimizing HIFU transducer design and irradiation settings to achieve maximal efficiency, defined as the minimal EEF, in simulated coagulative ablation scenarios.