Modeling the axial extension of a transmission line source within iterative reconstruction via multiple transmission sources.

Published

Journal Article

Reconstruction algorithms for transmission tomography have generally assumed that the photons reaching a particular detector bin at a particular angle originate from a single point source. In this paper, we highlight several cases of extended transmission sources, in which it may be useful to approach the estimation of attenuation coefficients as a problem involving multiple transmission point sources. Examined in detail is the case of a fixed transmission line source with a fan-beam collimator. This geometry can result in attenuation images that have significant axial blur. Herein it is also shown, empirically, that extended transmission sources can result in biased estimates of the average attenuation, and an explanation is proposed. The finite axial resolution of the transmission line source configuration is modeled within iterative reconstruction using an expectation-maximization algorithm that was previously derived for estimating attenuation coefficients from single photon emission computed tomography (SPECT) emission data. The same algorithm is applicable to both problems because both can be thought of as involving multiple transmission sources. It is shown that modeling axial blur within reconstruction removes the bias in the average estimated attenuation and substantially improves the axial resolution of attenuation images.

Full Text

Duke Authors

Cited Authors

  • Bowsher, JE; Tornai, MP; Peter, J; González Trotter, DE; Krol, A; Gilland, DR; Jaszczak, RJ

Published Date

  • March 2002

Published In

Volume / Issue

  • 21 / 3

Start / End Page

  • 200 - 215

PubMed ID

  • 11989845

Pubmed Central ID

  • 11989845

Electronic International Standard Serial Number (EISSN)

  • 1558-254X

International Standard Serial Number (ISSN)

  • 0278-0062

Digital Object Identifier (DOI)

  • 10.1109/42.996339

Language

  • eng