Share Email Print
cover

Proceedings Paper

Anti-scatter grid evaluation for wide-cone CT
Author(s): Roman Melnyk; John Boudry; Xin Liu; Mark Adamak
Format Member Price Non-Member Price
PDF $14.40 $18.00
cover GOOD NEWS! Your organization subscribes to the SPIE Digital Library. You may be able to download this paper for free. Check Access

Paper Abstract

Scatter is a significant source of image artifacts in wide-cone CT. Scatter management includes both scatter rejection and scatter correction. The common scatter rejection approach is to use an anti-scatter grid (ASG). Conventional CT scanners (with detector coverage not exceeding 40mm along the patient axis) typically employ one-dimensional (1D) ASGs. Such grids are quite effective for small cone angles. For larger cone angles, however, simply increasing the aspect ratio of a 1D ASG is not sufficient. In addition, a 1D ASG offers no scatter rejection along the patient axis. To ensure adequate image quality in wide-cone CT, a two-dimensional (2D) ASG is needed. In this work, we measured the amount of scatter and the degree of image artifacts typically attributable to scatter for four prototype 2D ASG designs, and we compared those to a 1D ASG. The scatter was measured in terms of the scatter-toprimary ratio (SPR). The cupping and ghosting artifacts were assessed through quantitative metrics. For the 2D ASGs, when compared to the 1D ASG, the SPR decreased by up to 66% and 75% for 35cm water and 48cm polyethylene, respectively, phantoms, at 80-160mm apertures (referenced to isocenter), as measured by the pinhole method. As measured by the two-aperture method, the SPR reduction was 59%-68% at isocenter for the 35cm water phantom at 160mm aperture. The cupping artifact was decreased by up to ~80%. The ghosting artifact was reduced as well. The results of the evaluation clearly demonstrate the advantage of using a 2D ASG for wide-cone CT.

Paper Details

Date Published: 19 March 2014
PDF: 7 pages
Proc. SPIE 9033, Medical Imaging 2014: Physics of Medical Imaging, 90332P (19 March 2014); doi: 10.1117/12.2043619
Show Author Affiliations
Roman Melnyk, GE Healthcare (United States)
John Boudry, GE Healthcare (United States)
Xin Liu, Missouri Univ. of Science and Technology (United States)
Mark Adamak, GE Healthcare (United States)


Published in SPIE Proceedings Vol. 9033:
Medical Imaging 2014: Physics of Medical Imaging
Bruce R. Whiting; Christoph Hoeschen, Editor(s)

© SPIE. Terms of Use
Back to Top