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Design and Safety Assessment of Wearable Transcranial Low-Intensity Pulsed Ultrasound Devices
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- Author / Creator
- Qi, Shi-ang
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Mental illness grow to become one of the most significant issues in the global medical burden. Ultrasound therapy has shown excellent performance in many clinical applications. Some encouraging evidence has shown that transcranial ultrasound stimulation (TUS) has a beneficial effect on relieving symptoms of mental illness (neuropsychiatric disorders). However, the commercially available low-intensity pulsed ultrasound (LIPUS) devices are usually bulky, power-consuming, and not designed explicitly for transcranial stimulation. There is a need for the implementation of a portable LIPUS device suitable for area-constrained embedded applications designed particularly for applying ultrasound stimulation to the brain. To address this need, this study designs and implements an internet of things (IoT) portable LIPUS generation system for TUS application.
The LIPUS generating system is composed of head-mounted transmission equipment, a LIPUS signal driving device, and a mobile application. In the head-mounted transmission equipment, in addition to the necessary accessories and appearance parts, the main components include an ultrasonic transducer, a rubber cap, the ultrasound agents, and an impedance matching circuit board. Studies are carried out to investigate the applicable ultrasound generation characteristic. The driving circuit module, the Bluetooth module, the power module, and the appearance accessories form a LIPUS signal driving module. The ultimate goal of this work is to design a prototype LIPUS generation system that is implemented using discrete components. After verification, the LIPUS generator can work appropriately after manufacture, and can generate LIPUS power from 30 mW to 590 mW (LIPUS intensity from 6.1 mW/cm^2 to 120 mW/cm^2) at the resonant frequency of 1.5 MHz of the transducer.
In addition, there have been a few studies that have estimated the risk of using therapeutic ultrasound. After developing a head-mounted LIPUS device, verification is performed to evaluate possible tissue damage when different intensity levels of LIPUS stimulation are applied through the temple to the brain. Our computer simulations and in vitro experiments show that our customized LIPUS devices can safely deliver small doses of low-intensity pulsed ultrasound to the brain through the skull without damage to the contacted skin and inner tissue. When a higher dose of LIPUS is applied to the temple, the skin in contact with the transducer may produce temporarily reversible injury. These results show that this approach has the potential to be used in the treatment of many neurological diseases as a TUS method in the future.
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- Graduation date
- Fall 2020
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- Type of Item
- Thesis
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- Degree
- Master of Science
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- License
- Permission is hereby granted to the University of Alberta Libraries to reproduce single copies of this thesis and to lend or sell such copies for private, scholarly or scientific research purposes only. Where the thesis is converted to, or otherwise made available in digital form, the University of Alberta will advise potential users of the thesis of these terms. The author reserves all other publication and other rights in association with the copyright in the thesis and, except as herein before provided, neither the thesis nor any substantial portion thereof may be printed or otherwise reproduced in any material form whatsoever without the author's prior written permission.