[Rtk-users] Conjugate Gradient Artefact

[Jonathan Mason]

Hello RTK users,

I have been using RTK for a couple of weeks now, and really like the
software. The extensive number of tools available is really impressive
and helpful, so thanks!

I have been experiencing an cylindrical artefact in using conjugate
gradient reconstruction — illustrated in the attached images along with
FDK with no artefact — of which I am unsure of its origin. The data is a
scan of a thorax phantom from a Varian on-board imager. At first I
suspected it was due to the specimen extending beyond the reconstruction
volume, but extending this unfortunately did not help. Something else I
have noticed is that the FOV filter isolates just this pale cylindrical
artefact around the centre of rotation.

Do you know of the cause of this effect, or how it could be remedied?

Best wishes,

Jonathan

-- 
The University of Edinburgh is a charitable body, registered in
Scotland, with registration number SC005336.

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