Tailoring nonlinear ultrasound beams using acoustic lenses

Abstract

Acoustic holographic lenses, i.e., acoustic holograms, can tailor ultrasound beams to precisely construct elaborate focal patterns. Due to their valuable capabilities, acoustic holograms are being rapidly investigated for a wide range of applications in physical acoustics and biomedical ultrasound. Modeling and demonstrating acoustic holograms in linear regimes is well documented in the literature. However, Acoustic holograms have the potential to improve the precision and affordability of therapeutic high-intensity focused ultrasound (HIFU). In this work, we will show the effects of nonlinear propagation on ultrasound fields tailored by acoustic holograms. The intensity-dependent effects of harmonic generation, diffraction, and nonlinear gain on the constructed pressure pattern are discussed. In addition, an accelerated method for simulating high-intensity 3D holographic ultrasound is introduced. We will show how the proposed algorithm greatly reduces the computational load for designing and predicting high-intensity holographic ultrasound patterns. This expedites the procedure of designing the acoustic lens, which allows for a more rapid and seamless implementation, especially in medical settings.