Analysis of Ablated Lesions In Two-Stage Ultrasound Depending on Heating Duration

Abstract

Histotripsy is a non-invasive therapeutic technique that fragments soft tissue through cavitation-induced mechanical stress. While two-stage approaches have recently gained attention for enhancing control over ablation precision, the relationship between thermal preconditioning and lesion morphology remains underexplored. In this study, we investigate a two-stage histotripsy using a single-frequency (3.5 MHz) ultrasound. The pulse sequence included stage 1 heating of varying durations (5.5, 10, or 16 seconds), followed by stage 2 mechanical ablation. As the stage 1 duration increased, ablated regions were formed toward the transducer's surface and gradually lost their trailing structures. Our findings suggest that lesion formation in the two- stage histotripsy can be affected by tuning thermal exposure duration.