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Dissertation
Interaction of non-thermal, non-cavitational 20-100 kHz ultrasound and biological tissue: modeling and experimental validation
Doctor of Philosophy (Ph.D.), Drexel University
2015
DOI:
https://doi.org/10.17918/etd-6983
Abstract
The primary goal of this work was to develop and verify a semi-empirical model that is capable of elucidating the mechanisms of interaction between low frequency (20 kHz), low pressure amplitude (55 kPa peak-peak) - corresponding to intensity equal to100 mW/cm2 ((ISPTP), spatial peak, temporal peak) - ultrasound and biological tissue. The novelty of this experimentally confirmed investigation is that it is the first relevant systematic approach examining such interaction. The interaction is of substantial clinical importance as it enables wound management (accelerated healing of chronic wounds) and non-invasive transdermal drug delivery at ultrasound energy levels, which are considered safe for prolonged exposure by the FDA. Specifically, as evidenced in the following the intentional use of low-intensity of 100 mW/cm2, spatial-peak temporal-peak (ISPTP), rules out potentially hazardous mechanisms of interaction such as inertial cavitation and thermal heating. Modeling and experimental verification were based on the novel design of a lightweight (<100g), fully wearable, tether-free, and rechargeable battery powered ultrasound applicator that enables safe outpatient care. Furthermore, this thesis contributed to enhanced understanding of the mechanical forces generated by the applicator and the analysis procedure developed permits an estimation of the magnitude of these forces generated within tissue. The outcome of the modeling indicates that the possible mechanisms of action are most likely associated with non-thermal, non-inertial cavitational effects. The in vitro and in vivo results of this study corroborate that the ultrasound applicator developed is capable of accelerating the healing process of chronic wounds, such as venous- and diabetic ulcers and can also enhance the efficiency of noninvasive, transdermal delivery of topically applied drugs.
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Details
- Title
- Interaction of non-thermal, non-cavitational 20-100 kHz ultrasound and biological tissue
- Creators
- Christopher R. Bawiec - DU
- Contributors
- Peter Andreas Lewin (Advisor) - Drexel University (1970-)
- Awarding Institution
- Drexel University
- Degree Awarded
- Doctor of Philosophy (Ph.D.)
- Publisher
- Drexel University; Philadelphia, Pennsylvania
- Number of pages
- xvi, 134 pages
- Resource Type
- Dissertation
- Language
- English
- Academic Unit
- School of Biomedical Engineering, Science, and Health Systems (1997-2026); Drexel University
- Other Identifier
- 6983; 991014632843204721