# Pre/post-op CBCT matching
**URL:** https://discourse.slicer.org/t/pre-post-op-cbct-matching/11438
**Category:** Support
**Tags:** registration
**Created:** [May 6, 2020, 10:47pm UTC](https://discourse.slicer.org/t/pre-post-op-cbct-matching/11438 "2020-05-06T22:47:26Z")
**Posts on this page:** 5
**Page:** 1
### Author:  [@Aras\_J](https://discourse.slicer.org/u/Aras_J)
#### Post date: [May 6, 2020, 10:47pm UTC](https://discourse.slicer.org/t/pre-post-op-cbct-matching/11438/1 "2020-05-06T22:47:26Z")
Hello everyone,
I am very new to Slicer and clicking myself through the basic tutorials learning this amazing tool step by step. But: what do i have to search for or is the any tutorial for following task:
Loading pre- and post op cbct’s of the skull - “match”?! them and then automatically define lower jaw movement in the translation and rotational axes.
Thanks in advance and delete my post or relink somewhere i find the answers if this is too basic/spam.
best regards from germany
AJ
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### Author:  [@timeanddoctor](https://discourse.slicer.org/u/timeanddoctor)
#### Post date: [May 7, 2020, 2:13am UTC](https://discourse.slicer.org/t/pre-post-op-cbct-matching/11438/2 "2020-05-07T02:13:18Z")
You can registrate the pre and post op sull by landmark registration. and calculate the transform for the angle and line moving.
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### Author:  [@cpinter](https://discourse.slicer.org/u/cpinter)
#### Post date: [May 7, 2020, 8:38am UTC](https://discourse.slicer.org/t/pre-post-op-cbct-matching/11438/3 "2020-05-07T08:38:30Z")
@Aras_J This is a completely legit question, don’t worry 🙂 The term you are looking for are image registration, the verb for which is register (not registrate).
There are several modules in Slicer to do it, including the already mentioned landmark registration (for which I recommend the Fiducial registration wizard in the SlicerIGT extension). For images the first way I’d suggest trying is automatic image based registration. For that I think the SlicerElastix extension is your best bet, but there are others like the BRAINS registration, for which you can find tutorials and the registration case library [here](https://www.slicer.org/wiki/Documentation/4.10/Training#Registration).
In your specific case what I recommend is doing a rigid registration of the two CBCTs using SlicerElastix so that the jaws can be assessed in the same frame of reference, then segment (delineate, contour) the lower jaws using Segment Editor (there are tons of material about it in the forum and the documentation), and then find out the spatial relationship of the two segmented jaws.
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### Author:  [@joachim](https://discourse.slicer.org/u/joachim)
#### Post date: [May 8, 2020, 11:17am UTC](https://discourse.slicer.org/t/pre-post-op-cbct-matching/11438/4 "2020-05-08T11:17:54Z")
If you want to learn Slicer, I will recommend you these nice tutorials: [https://github.com/SlicerMorph/W\_2020](https://github.com/SlicerMorph/W_2020) (under _LabXX\_Slicer\_X_). Take a look at [this example](https://github.com/SlicerMorph/W_2020/tree/master/Lab09_Slicer_Scripting#example-1-aligning-volumes-using-landmarks-frankfort-alignment-plane).
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### Author:  [@Aras\_J](https://discourse.slicer.org/u/Aras_J)
#### Post date: [May 9, 2020, 11:14am UTC](https://discourse.slicer.org/t/pre-post-op-cbct-matching/11438/5 "2020-05-09T11:14:13Z")
Thank you very much.