Diagnostic ultrasound has become invaluable to healthcare professions for the purpose of imaging soft tissue without the risk of exposure to damaging, ionizing radiation. However, the majority of commercially available transducers have rigid, fixed interfaces that cannot conform to the surface of the human body. Such limitations both introduce a potential air gap (requiring the application of ultrasound gel) and make long-term monitoring impractical. In this work, I propose a novel flexible 2D ultrasound phased array with adaptive phasing that is capable of compensating for the radius of curvature. I describe the phasing algorithm and illustrate the detrimental effect of a lack of phase correction through simulation. I conduct phase detection by using time of arrival (TOA) without additional external hardware. In addition to simulations, I provide details of the fabrication process of a flexible 16 by 16 element array. The manufactured array, with an operating frequency of 1.4MHz and bandwidth of 41.3%, was capable of generating pressures up to 600 kPa. Finally, I conduct an in-vivo human study to demonstrate the functionality of the array on a human humerus. Although visible without phase correction, the location of the bone can easily be tracked in real-time after applying the correction algorithm.
| Identifer | oai:union.ndltd.org:columbia.edu/oai:academiccommons.columbia.edu:10.7916/d8-d1kz-kq89 |
| Date | January 2021 |
| Creators | Elloian, Jeffrey |
| Source Sets | Columbia University |
| Language | English |
| Detected Language | English |
| Type | Theses |
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