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Artifact analysis of approximate helical cone‐beam CT reconstruction algorithms
Author(s) -
Köhler Th.,
Proksa R.,
Bontus C.,
Grass M.,
Timmer J.
Publication year - 2002
Publication title -
medical physics
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.473
H-Index - 180
eISSN - 2473-4209
pISSN - 0094-2405
DOI - 10.1118/1.1413518
Subject(s) - aliasing , algorithm , iterative reconstruction , artifact (error) , scanner , projection (relational algebra) , isotropy , mathematics , helical scan , cone beam computed tomography , detector , computer vision , artificial intelligence , computer science , optics , physics , computed tomography , filter (signal processing) , medicine , telecommunications , digital recording , magnetic tape , radiology
In this paper, four approximate cone‐beam CT reconstruction algorithms are compared: Advanced single slice rebinning (ASSR) as a representative of algorithms employing a two dimensional approximation, PI, PI‐SLANT, and 3‐PI which all use a proper three dimensional back‐projection. A detailed analysis of the image artifacts produced by these techniques shows that aliasing in the z ‐direction is the predominant source of artifacts for a 16‐row scanner with 1.25 mm nominal slice thickness. For a detector with isotropic resolution of 0.5 mm, we found that ASSR and PI produce different kinds of artifacts which are almost at the same level, while PI‐SLANT produces none of these artifacts. It is shown that the use of redundant data in the 3‐PI method suppresses aliasing artifacts efficiently for both scanners.