title: Investigation into the mechanisms of tissue atomization by high-intensity focused ultrasound.
abstract: Ultrasonic atomization, or the emission of a fog of droplets, was recently proposed to explain tissue fractionation in boiling histotripsy. However, even though liquid atomization has been studied extensively, the mechanisms underlying tissue atomization remain unclear. In the work described here, high-speed photography and overpressure were used to evaluate the role of bubbles in tissue atomization. As static pressure increased, the degree of fractionation decreased, and the ex vivo tissue became thermally denatured. The effect of surface wetness on atomization was also evaluated in vivo and in tissue-mimicking gels, where surface wetness was found to enhance atomization by forming surface instabilities that augment cavitation. In addition, experimental results indicated that wetting collagenous tissues, such as the liver capsule, allowed atomization to breach such barriers. These results highlight the importance of bubbles and surface instabilities in atomization and could be used to enhance boiling histotripsy for transition to clinical use.
authors: Center for Industrial and Medical Ultrasound, Applied Physics Laboratory, University of Washington, Seattle, Washington, USA. Electronic address: jcsimon@uw.edu.
authors: Julianna C
authors: JC
authors: Simon
authors: Center for Industrial and Medical Ultrasound, Applied Physics Laboratory, University of Washington, Seattle, Washington, USA; Department of Acoustics, Physics Faculty, Moscow State University, Moscow, Russia.
authors: Oleg A
authors: OA
authors: Sapozhnikov
authors: Center for Industrial and Medical Ultrasound, Applied Physics Laboratory, University of Washington, Seattle, Washington, USA.
authors: Yak-Nam
authors: YN
authors: Wang
authors: Center for Industrial and Medical Ultrasound, Applied Physics Laboratory, University of Washington, Seattle, Washington, USA; Department of Acoustics, Physics Faculty, Moscow State University, Moscow, Russia.
authors: Vera A
authors: VA
authors: Khokhlova
authors: Center for Industrial and Medical Ultrasound, Applied Physics Laboratory, University of Washington, Seattle, Washington, USA.
authors: Lawrence A
authors: LA
authors: Crum
authors: Center for Industrial and Medical Ultrasound, Applied Physics Laboratory, University of Washington, Seattle, Washington, USA.
authors: Michael R
authors: MR
authors: Bailey
mesh_terms: D000818:Animals; D002417:Cattle; D004307:Dose-Response Relationship, Radiation; D019220:High-Energy Shock Waves; D057086:High-Intensity Focused Ultrasound Ablation / Q000379:methods*; D066298:In Vitro Techniques; D008099:Liver / Q000502:physiology* / Q000528:radiation effects*; D009330:Nebulizers and Vaporizers; D011312:Pressure; D011829:Radiation Dosage
keywords: Atomization; Boiling; Capillary wave; Cavitation; High-intensity focused ultrasound; Histotripsy; Instability