Cavitation-induced pressure saturation: a mechanism governing bubble nucleation density in histotripsy
Year: 2024
Type: article
Abstract: Objective. Histotripsy is a noninvasive focused ultrasound therapy that mechanically disintegrates tissue by acoustic cavitation clouds. In this study, we investigate a mechanism limiting the density of bubbles that can nucleate during a histotripsy pulse. In this mechanism, the pressure generated by the initial bubble expansion effectively negates the incident pressure in the vicinity of the bubble. From this effect, the immediately adjacent tissue is prevented from experiencing the transient tension to nucleate bubbles . Approach. A Keller–Miksis-type single-bubble model was employed to evaluate the dependency of this effect on ultrasound pressure amplitude and frequency, viscoelastic medium properties, bubble nucleus size, and transducer geometric focusing. This model was further combined with a spatial propagation model to predict the peak negative pressure field as a function of position from a cavitating bubble. Main results . The single-bubble model showed the peak negative pressure near the bubble surface is limited to the inertial cavitation threshold. The predicted bubble density increased with increasing frequency, tissue viscosity, and transducer focusing angle. The simulated results were consistent with the trends observed experimentally in prior studies, including changes in density with ultrasound frequency and transducer F -number. Significance. The efficacy of the therapy is dependent on several factors, including the density of bubbles nucleated within the cavitation cloud formed at the focus. These results provide insight into controlling the density of nucleated bubbles during histotripsy and the therapeutic efficacy.
Source: Physics in Medicine and Biology
Authors: Adam D Maxwell, Eli Vlaisavljevich
Institutions: University of Washington, Virginia Tech
Language: English
Subfield: Biomedical Engineering
Field: Engineering
Domain: Physical Sciences
Open Access status: bronze
Awards: G19172839, Ultrasound-guided Intrinsic Threshold Histotripsy for the Non-invasive Ablation of Uterine Fibroids, Noninvasive histotripsy ablation of fibrotic tissue in benign prostatic hyperplasia, Developing Methods for Precise, Safe and Target-location Specific Histotripsy of Liver Tumors, Deploying Histotripsy Based Tumor Ablation Strategies to Treat Pancreatic Cancer
OpenAlex ID: W4393097582
