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Proceedings Paper

Fluence-field modulated x-ray CT using multiple aperture devices
Author(s): J. Webster Stayman; Aswin Mathews; Wojciech Zbijewski; Grace Gang; Jeffrey Siewerdsen; Satomi Kawamoto; Ira Blevis; Reuven Levinson
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Paper Abstract

We introduce a novel strategy for fluence field modulation (FFM) in x-ray CT using multiple aperture devices (MADs). MAD filters permit FFM by blocking or transmitting the x-ray beam on a fine (0.1-1 mm) scale. The filters have a number of potential advantages over other beam modulation strategies including the potential for a highly compact design, modest actuation speed and acceleration requirements, and spectrally neutral filtration due to their essentially binary action. In this work, we present the underlying MAD filtration concept including a design process to achieve a specific class of FFM patterns. A set of MAD filters is fabricated using a tungsten laser sintering process and integrated into an x-ray CT test bench. A characterization of the MAD filters is conducted and compared to traditional attenuating bowtie filters and the ability to flatten the fluence profile for a 32 cm acrylic phantom is demonstrated. MAD-filtered tomographic data was acquired on the CT test bench and reconstructed without artifacts associated with the MAD filter. These initial studies suggest that MAD-based FFM is appropriate for integration in clinical CT system to create patient-specific fluence field profile and reduce radiation exposures.

Paper Details

Date Published: 22 March 2016
PDF: 6 pages
Proc. SPIE 9783, Medical Imaging 2016: Physics of Medical Imaging, 97830X (22 March 2016);
Show Author Affiliations
J. Webster Stayman, Johns Hopkins Univ. (United States)
Aswin Mathews, Johns Hopkins Univ. (United States)
Wojciech Zbijewski, Johns Hopkins Univ. (United States)
Grace Gang, Johns Hopkins Univ. (United States)
Jeffrey Siewerdsen, Johns Hopkins Univ. (United States)
Satomi Kawamoto, Johns Hopkins Univ. (United States)
Ira Blevis, Philips Medical Systems (Israel)
Reuven Levinson, Philips Medical Systems (Israel)

Published in SPIE Proceedings Vol. 9783:
Medical Imaging 2016: Physics of Medical Imaging
Despina Kontos; Thomas G. Flohr, Editor(s)

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