Investigation of Histotripsy Cavitation and Acoustic Droplet Vaporization From Perfluorocarbon Nanoparticles

Histotripsy is a non-invasive and non-thermal focused ultrasound therapy that can be used to ablate tissue within the body while overcoming many of the limitations of thermal ablation. Histotripsy utilizes short-duration, high pressure ultrasound pulses to create a cavitation bubble cloud of numerous rapidly expanding and collapsing bubbles, which cause mechanical stress on the targeted region. Histotripsy contains multiple subtypes including intrinsic threshold, shock scattering, and boiling histotripsy, where intrinsic threshold histotripsy utilizes single cycle pulses focused to a single point to create a bubble cloud from the peak negative pressure (p- ≥ 25 MPa for water-based tissues). Nanoparticle-mediated histotripsy (NMH) uses perfluorocarbon-filled nanoparticles to create bubble clouds at lower pressures than that of the intrinsic threshold of histotripsy. Prior studies have shown that nanodroplets (NDs) and nanocone clusters (NCCs) both reduce the cavitation threshold, but further investigation on different parameters to optimize treatments have not fully been studied. Additional research is needed for the characterization of these nanoparticles with different pulsing parameters such as cycle number and frequency in order to better predict and understand the mechanisms underlying NMH. In this thesis, I investigate the ability of new nanodroplets and nanocone clusters to reduce histotripsy cavitation threshold with NMH. I also investigate the effect that multi-cycle pulsing parameters have on NMH and stable bubble formation from acoustic droplet vaporization (ADV) for nancone clusters. The culmination of this thesis will advance our understanding of the behavior of acoustically-active nanoparticles when exposed to varied pulsing schemes and frequencies. This knowledge will allow for the further investigation of more efficient, effective, and safe methods for clinical focused ultrasound therapies.

Name thesis:degree_name

Master of Science

Level thesis:degree_level

masters

Discipline thesis:degree_discipline

Biomedical Engineering

Department dc:contributor.department

Department of Biomedical Engineering and Mechanics

Grantor dc:publisher

Virginia Tech

Year dc:date.issued

2023

Author dc:creator

• Pearson, Dylan Irie

Chair dc:contributor.committeechair

• Vlaisavljevich, Eli

Committee members dc:contributor.committeemember

• Wang, Vincent M.
• Durmaz, Yasemin

• Focused Ultrasound
• Histotripsy
• Nanoparticles
• Nanoparticle-mediated Histotripsy

Statement dc:rights

• In Copyright

Licence dc:rights.uri

• http://rightsstatements.org/vocab/InC/1.0/

Language dc:language.iso

en

Dc Identifier Other

vt_gsexam:37959

OAI identifier oai:identifier

oai:vtechworks.lib.vt.edu:10919/115630