Maximizing the information content of dual energy x-ray and CT imaging
Abstract/Contents
- Abstract
- Computed tomography (CT) has become an essential tool in modern medicine since its introduction in the early 1970s. It generates cross-sectional images of the body's x-ray attenuation by measuring the transmission of x-rays in many directions. Because CT uses ionizing radiation, a governing principle is to use the least amount of radiation dose that still provides diagnostic-quality images. One approach to ensure that dose is appropriately used is to explore the information content of CT scans. This work examines efficient methods for encoding, storing, and extracting information from CT scans, especially as they pertain to spectral x-ray imaging. CT systems that can take advantage of the different attenuation properties of x-rays at different energies can provide additional diagnostic information, known as dual energy imaging. A new technique called Synthetic CT is introduced that enables images from CT protocols other than what was acquired to be retrospectively synthesized. With this tool, the information contained within a dual energy scan can be used to demonstrate the effect of protocol selection on image quality and dose distribution. In addition to experimentally validating the developed synthetic CT theory, further efforts have led to image-based synthetic CT, incorporation of electronic noise models for ultra low dose simulation, and a simple graphical user interface that demonstrates the flexibility of synthetic CT. We also explore an important spectral imaging technology -- photon counting detectors with energy discrimination capabilities. In principle, these detectors capture all the spectral information of transmitted x-rays by counting the number of photons at each energy. Optimal configurations of ideal photon counting detectors are first investigated, leading to the elegant discovery that two energy-dependent weighted counts can form a sufficient statistic for dual energy imaging. In practice, photon counting detectors have count rate limitations and imperfect spectral responses. The performance of realistic photon counting detectors is modeled and compared to conventional dual kV techniques. We find that both optimized photon counting and dual kV systems can significantly increase the dose efficiency of dual energy imaging.
Description
| Type of resource | text |
|---|---|
| Form | electronic; electronic resource; remote |
| Extent | 1 online resource. |
| Publication date | 2012 |
| Issuance | monographic |
| Language | English |
Creators/Contributors
| Associated with | Wang, Adam Shar |
|---|---|
| Associated with | Stanford University, Department of Electrical Engineering |
| Primary advisor | Pelc, Norbert J |
| Thesis advisor | Pelc, Norbert J |
| Thesis advisor | Fahrig, Rebecca |
| Thesis advisor | Nishimura, Dwight George |
| Advisor | Fahrig, Rebecca |
| Advisor | Nishimura, Dwight George |
Subjects
| Genre | Theses |
|---|
Bibliographic information
| Statement of responsibility | Adam Shar Wang. |
|---|---|
| Note | Submitted to the Department of Electrical Engineering. |
| Thesis | Thesis (Ph.D.)--Stanford University, 2012. |
| Location | electronic resource |
Access conditions
- Copyright
- © 2012 by Adam Shar Wang
- License
- This work is licensed under a Creative Commons Attribution Non Commercial 3.0 Unported license (CC BY-NC).
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