System Level Approach towards Intelligent Healthcare Environment

• Main Author: Avirovik, Dragan
• Other Authors: Mechanical Engineering
• Format: Others
• Published: Virginia Tech 2014
• Subjects: actuators; medical; piezoelectric; shape memory alloy; wireless capsule endoscopy
• Online Access: http://hdl.handle.net/10919/49581

Surgical procedures conducted without proper guidance and dynamic feedback mechanism could lead to unintended consequences. In-vivo diagnostics and imaging (the Gastro-Intestinal tract) has shown to be inconvenient for the patients using traditional endoscopic instruments and often these conventional methods are limited in terms of their access to various organs (e.g. small intestines). Embedding sensors inside the living body is complex and further the communication with the implanted sensors is challenging using the current RF technology. Additionally, continuous replacement and/or batteries recharging for wireless sensors networks both in-vivo and ex-vivo adds towards the complexity. Advances in diagnostics and prognostics techniques require development at multiple levels through systems approach, guided by the futuristic intelligent decision making environment that reduces the human interference. The demands are not only at the component level, but also at the connectivity of the components such that secure, sustainable, self-reliant, and intelligent environment can be realized. This thesis provides important breakthroughs required to achieve the vision of intelligent healthcare environment. The research contributions of this thesis provide foundation for developing a new architecture for continuous medical diagnostic and monitoring. The chapters in this thesis cover four fundamental technologies covering the in-vivo imaging, ex-vivo imaging, energy for sensors, and acoustic communication. These technologies are: locomotion mechanism for wireless capsule endoscope (WCE), multifunctional image guided surgical (MIGS) platform, shape memory alloy (SMA) thermal energy harvester and thermo-acoustic sonar using carbon nanotube (CNT) sheets. First, two types of locomotion mechanisms were developed, the first one inspired by millipede legged type mechanism and the second one based on the traveling waves that were induced onto the walls of the WCEs through vibration. Both mechanisms utilize piezoelectric actuators and couple their dynamics and actuation capability in order to achieve propulsion. This controlled locomotion will provide WCE advantage in terms of conducting localized diagnostics. Next, in order to conduct ex-vivo surgical procedures using the OCT such as removing the unwanted tissue and tumors short distance beneath the skin, MIGS platform was developed. The MIGS platform is composed of three key elements: optical coherence tomography (OCT) probe, laser scalpel and high precision miniature scanning and positioning stage. The focus in this dissertation was on design and development of the programmable scanning and positioning stage. The combination of in-vivo tool such as WCE and ex-vivo tool such as MIGS will provide opportunity to conduct many non-invasive procedures which will save time and cost. In order to power the feedback sensors that assist in remote operation of surgical procedures and automation of the diagnostic algorithms, an energy harvester technology based on the SMA thermal engine was designed, fabricated, and characterized. A mechano-thermal model for the overall SMA engine was developed and experimentally validated. Finally, the thermo-acoustic sound generation mechanism using CNT sheets was investigated with the goal of developing techniques for acoustic localization of WCE and customized sound generation devices. CNT thermo-acoustic projectors were modeled and experimentally characterized to quantify the dynamics of the system under varying drive conditions. The overall vision of this thesis is to lay down the foundation for intelligent healthcare environment that provides the ability to conduct automated diagnostics, prognostics, and non-invasive surgical procedures. In accomplishing this vision, the thesis has addressed several key fundamental aspects of various technologies that will be required for implementing the automation algorithms. === Ph. D.