Zoom Meeting (Information posted at the end of the announcement)
Design and Applications of Cold-Cathode X-ray Imaging Systems
X-ray computed tomography (CT) and planar x-ray imaging are mainstays of modern clinical care. The electron generation mechanism in standard x-ray tubes - specifically, a thermionic cathode - is reliable and capable of high current. However, thermionic cathodes are bulky, and cannot be pulsed quickly. Non-thermionic ('cold-cathode') electron generation can be exploited to make a smaller and rapidly pulsable x-ray source. Such an x-ray source could improve not just the portability of x-ray devices, but would allow for a CT system to operate by pulsing a distributed ring of x-ray sources instead of rotating a single large x-ray source.
Furthermore, cold-cathode x-ray sources could allow for new signal acquisition and processing paradigms in the x-ray domain. This includes time-based image acquisition techniques, such as elastography and photon-counting measurements.
In this dissertation, I discuss (1) the development of two novel types of cold-cathode x-ray sources: an ultraviolet photocathode-based source, and a silicon field emission chip; (2) novel methods for planar x-ray image acquisition, including a demonstration of dynamic x-ray elastography using a pulsed photocathode x-ray source; and (3) applications of modern signal processing techniques to the tomographic image reconstruction problem.
In an epilogue, I discuss our research on N95 respirator sterilization and re-use for crisis situations.
Thesis Supervisor:
Rajiv Gupta, MD, PhD
Associate Professor of Radiology, HMS/MGH
Thesis Committee Chair:
Benjamin Vakoc, PhD
Associate Professor of Dermatology, HMS/MGH
Thesis Readers:
Matthew Rosen, PhD
Assistant Professor of Radiology, A.A. Martinos Center for Biomedical Imaging, MGH
Richard Lanza, PhD
Senior Research Scientist, Nuclear Science and Engineering, MIT
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Zoom information
Topic: Avilash Kalpathy Cramer PhD Defense
Time: October 2, 2020 02:00 PM Eastern Time (US and Canada)
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