[Rtk-users] White spot at center of rotation during Half fan reconstruction

[Simon Rit]

Hi,
Half-scan reconstruction are notoriously sensitive to inconsistencies with
the integral model at the center of the object. The weighting function
enhances these inconsistencies and creates such artefacts. Removing them
would require correcting the data for scatter, beam hardening etc.
Contrast can be improved by correcting scatter, for which RTK does not have
a lot of solutions except Boellaard algorithm
<https://github.com/RTKConsortium/RTK/issues/454>.
Simon

On Mon, Jan 20, 2025 at 1:15 PM Anshika G <Anshika.G at panaceamedical.com>
wrote:

> Hi All,
>
> I have been using RTK for my CBCT reconstruction with the FDK algorithm.
>
> During half-fan reconstruction for a pelvic data with a 200 mm detector
> shift/offset (for reference attached Fig_1.png to show the offset), I am
> getting better results.
>
> However, I consistently encounter a white spot artefact at the center of
> rotation of reconstructed volume (attached Fig_2.png).
>
> Could anyone help explain the potential cause of this artifact?
>
> Additionally, I would appreciate suggestions on how to enhance contrast
> between tissue maps in the reconstructed image.
>
> Looking forward to your insights!
>
>
>
>
>
> Best regards,
> Anshika Goel
>
>
>
>
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