[Rtk-users] artifacts around high consistence small elements

[Cyril Mory]

Hi,

Unfortunately, you are facing a problem, called "Metal artifact 
reduction", that is still a topic of active research. That means there 
is no easy off-the-shelf answer to your question.
You could try :
- other reconstruction algorithms available in RTK, especially rtksart 
or rtkconjugategradient
- increasing the number of projections (it never hurts)
but keep in mind that it will probably have only a limited impact.
Or you can try implementing some known metal artifact reduction method 
in RTK (obviously this would take time, but on the bright side, you 
would learn how to code in RTK ! And we can provide help if you choose 
this path).
The following presentation should help you familiarize with the topic:
http://isssma2013.sciencesconf.org/conference/isssma2013/pages/Paris4june2013_jn2.ppt

Best regards,
Cyril

On 04/13/2015 01:43 PM, 1 1 wrote:
> Hi RTK users.
> I try reconstruct such object: plasticine with implantation of high consistence ( lead, Pb ) elements about 50-150 um
> Acquisition configuration: sdd: 344.1mm, sid: 344.1, shots: 640, rotation step: 0.3 deg, 1000x666, 700 dpi
> On volume i see artifacts in the form of luminescence and holes around elements.
>
> one of projections: http://i.imgur.com/iFesZ3o.png
> slices that demonstrate artifacts: http://i.imgur.com/RQExMO2.png, http://i.imgur.com/Th2fxzA.png
>
> what do you think may affect on them ? may be :
> - decrease rotation step, increase full rotation from 192 (in my case) to 360
> - detector with higher dpi
> ?
>
> probably there is necessary apply some filter ?
>
> These artifacts present not only in RTK, but other reconstruction software gives the same result. I dont beleive that its impossible to reconstruct such elements without artifacts, but i don't know the way where to investigate the problem.
>
> thank you
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