# Remove atifacts background after registration

**URL:** <https://discourse.slicer.org/t/remove-atifacts-background-after-registration/12551>\
**Category:** Support\
**Created:** [July 15, 2020, 10:17am UTC](https://discourse.slicer.org/t/remove-atifacts-background-after-registration/12551 "2020-07-15T10:17:11Z")\
**Posts on this page:** 4\
**Page:** 1

<div class="post-metadata">

**Author:** ![1116](https://avatars.discourse-cdn.com/v4/letter/1/439d5e/32.png) [@1116](https://discourse.slicer.org/u/1116)\
**Post date:** [July 15, 2020, 10:17am UTC](https://discourse.slicer.org/t/remove-atifacts-background-after-registration/12551/1 "2020-07-15T10:17:11Z")

</div>

After rigid registration using Elastix, I got CT data with artifacts at background

 ![캡처](https://us1.discourse-cdn.com/flex002/uploads/slicer/original/3X/1/1/11182dfd7f87e7ba54980beff0563e22d90760c5.png)  
is there any way to remove background remaining only head volume?

---

<div class="post-metadata">

**Author:** ![cpinter](https://sea2.discourse-cdn.com/flex002/user_avatar/discourse.slicer.org/cpinter/32/7995_2.png) [@cpinter](https://discourse.slicer.org/u/cpinter)\
**Post date:** [July 15, 2020, 10:45am UTC](https://discourse.slicer.org/t/remove-atifacts-background-after-registration/12551/2 "2020-07-15T10:45:44Z")

</div>

If you selected an output transform node, then instead of using the output volume, apply the transform on the moving volume.

---

<div class="post-metadata">

**Author:** ![1116](https://avatars.discourse-cdn.com/v4/letter/1/439d5e/32.png) [@1116](https://discourse.slicer.org/u/1116)\
**Post date:** [July 15, 2020, 12:28pm UTC](https://discourse.slicer.org/t/remove-atifacts-background-after-registration/12551/3 "2020-07-15T12:28:44Z")

</div>

Thank you for the reply!

It removes the background, but the demension and spacing do not fit with MR data.  
What should be done after applying the transform node?

---

<div class="post-metadata">

**Author:** ![cpinter](https://sea2.discourse-cdn.com/flex002/user_avatar/discourse.slicer.org/cpinter/32/7995_2.png) [@cpinter](https://discourse.slicer.org/u/cpinter)\
**Post date:** [July 15, 2020, 12:45pm UTC](https://discourse.slicer.org/t/remove-atifacts-background-after-registration/12551/4 "2020-07-15T12:45:27Z")

</div>

You probably didn’t actually apply the transform on the moving volume.

It can be done from the [Data module](https://slicer.readthedocs.io/en/latest/user_guide/modules/data.html) (right-click the transform column ans select the transform) or the [Transforms module](https://www.slicer.org/wiki/Documentation/Nightly/Modules/Transforms) (select transform, and move the volume under it)