A dynamic attenuator for computed tomography
Abstract/Contents
- Abstract
- The utilization of x-ray computed tomography (CT) has increased dramatically in recent decades. While extremely useful, a major drawback of CT scans is their use of ionizing radiation. Today, one quarter of the radiation dose received by the U.S. population can be attributed to CT scans. We present the use of a dynamic attenuator which is capable of personalizing the radiation usage in the scan. This attenuator is inspired by a stationary-source, inverse geometry CT scanner, which is an architecture with several advantages but which is also very complex. The dynamic attenuator consists of a series of movable wedges which together produce a time-varying, piecewise-linear thickness profile. In simulations, this attenuator reduces dose by 30% in nontargeted scans and 50% in targeted scans without increasing peak noise. On many datasets, this attenuator can also achieve order-of-magnitude dynamic range reductions, which may aid in the adoption of photon-counting detectors, a separate technology which may provide additional dose reductions. We show that most of these dose reduction benefits can be achieved using a real-time control algorithm to position the wedges dynamically during the scan. Additionally, we have developed a framework for optimizing the control of a broad range of dynamic attenuators. A prototype system suggests that the level of artifacts produced by the wedge transitions is within the range of tens of Hounsfield units, although further refinements are expected to reduce artifacts. Based on these positive results, we believe that this dynamic, piecewise-linear attenuator is a practical and effective option for CT.
Description
| Type of resource | text |
|---|---|
| Form | electronic; electronic resource; remote |
| Extent | 1 online resource. |
| Publication date | 2013 |
| Issuance | monographic |
| Language | English |
Creators/Contributors
| Associated with | Hsieh, Scott |
|---|---|
| Associated with | Stanford University, Department of Electrical Engineering. |
| Primary advisor | Pelc, Norbert J |
| Thesis advisor | Pelc, Norbert J |
| Thesis advisor | Fleischmann, Dominik |
| Thesis advisor | Nishimura, Dwight George |
| Advisor | Fleischmann, Dominik |
| Advisor | Nishimura, Dwight George |
Subjects
| Genre | Theses |
|---|
Bibliographic information
| Statement of responsibility | Scott Hsieh. |
|---|---|
| Note | Submitted to the Department of Electrical Engineering. |
| Thesis | Thesis (Ph.D.)--Stanford University, 2013. |
| Location | electronic resource |
Access conditions
- Copyright
- © 2013 by Scott Sigao Hsieh
- License
- This work is licensed under a Creative Commons Attribution Non Commercial 3.0 Unported license (CC BY-NC).
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