Comparative Study of Conventionally Focused and Non-Diffracting Frozen Waves in Diffractive Environments for Biomedical Applications

This paper presents a comparative analysis based on simulations of three acoustic focalization techniques employed in biomedical ultrasound: annular phased array, concave transducer, and non-diffracting “Frozen Waves.” The Frozen Waves technique, noted for its self-reconstruction capabilities, is evaluated for its consistency in acoustic field profile, even in diffractive environments. The analysis employs two simulation models: one in a homogeneous water medium and another incorporating a bone-like obstacle. In the homogeneous medium, the results were consistent with the defined parameters. When a bone-like obstacle was introduced, Frozen Waves demonstrated stable focalization, exhibiting less pressure attenuation and energy reflection. In contrast, both the annular phased array and concave transducer methods showed increased wavefront distortion and significant pressure accumulation at the obstacle site, with pressure increases of 155.26% and 163.16%, compared to the focal point pressure in the homogeneous model, respectively. These results highlight the resilience of Frozen Waves to diffraction and attenuation in complex environments, positioning them as a promising technique for enhancing the efficacy and safety of ultrasound-based medical procedures.