Transmission CT reconstruction for offset fan beam collimation

Author

Gilland, David R. ; Jaszczak, Ronald J. ; Coleman, R. Edward

Author_Institution

Dept. of Radiol., Duke Univ. Med. Center, Durham, NC, USA

Volume

47

Issue

4

fYear

2000

fDate

8/1/2000 12:00:00 AM

Firstpage

1602

Lastpage

1606

Abstract

Offset fan beam collimation has shown to be an effective means of obtaining transmission CT (TCT) data for SPECT attenuation correction. This paper compared three methods for handling the truncation problem and reconstructing this TCT data: iterative Os-FM and filtered backprojection (FBP) with two different pre-processing approaches. The first approach (FBP1) extends the fan beam projection by sinogram interpolation, and the second (FBP2) uses parallel beam rebinning. With a TCT spatial resolution phantom, FBP2 demonstrated a small degree of resolution loss which was equalized across methods after post-reconstruction filtering. With a thorax phantom, all methods performed adequately at high count level; however, at low count level, FBPI showed degraded image quality due to its handling of zero count projection bins. This finding was corroborated in patient images. It is concluded that at practical count levels, the iterative OS-FM method offers a clear advantage in TCT image quality compared to FBP methods

Keywords

gamma-ray absorption; image reconstruction; image resolution; interpolation; iterative methods; medical image processing; single photon emission computed tomography; SPECT attenuation correction; degraded image quality; fan beam projection; filtered backprojection; iterative Os-FM; medical diagnostic imaging; nuclear medicine; offset fan beam collimation; parallel beam rebinning; practical count levels; pre-processing approach; sinogram interpolation; thorax phantom; transmission CT reconstruction; truncation problem; zero count projection bins; Attenuation; Collimators; Computed tomography; Filtering; Image quality; Image reconstruction; Imaging phantoms; Interpolation; Iterative methods; Spatial resolution;

fLanguage

English

Journal_Title

Nuclear Science, IEEE Transactions on

Publisher

ieee

ISSN

0018-9499

Type

jour

DOI

10.1109/23.873022

Filename

873022