# Segmentation inside a ROI

**URL:** <https://discourse.slicer.org/t/segmentation-inside-a-roi/12588>\
**Category:** Support\
**Tags:** segmentation\
**Created:** [July 17, 2020, 12:17am UTC](https://discourse.slicer.org/t/segmentation-inside-a-roi/12588 "2020-07-17T00:17:14Z")\
**Posts on this page:** 3\
**Page:** 1

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**Author:** ![Jaswant](https://avatars.discourse-cdn.com/v4/letter/j/8baadc/32.png) [@Jaswant](https://discourse.slicer.org/u/Jaswant)\
**Post date:** [July 17, 2020, 12:17am UTC](https://discourse.slicer.org/t/segmentation-inside-a-roi/12588/1 "2020-07-17T00:17:15Z")

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My question is somewhat similar to ongoing discussion on ROI to segmentation topic.  
I am working on a whole body CT with contrast of a dog to segment bones, muscles and blood vessels of thoracic and pelvic limbs, axial skeleton and head&neck. In order to do so, I created ROI for each of these regions and have to create sub-volumes to do region-specific segmentations. Is there a direct way for me use only one master volume (whole body) and perform segmentation within a specific ROI. I am a novice, so please re-direct me an example, if available. Thank you very much in advance.

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**Author:** ![timeanddoctor](https://sea2.discourse-cdn.com/flex002/user_avatar/discourse.slicer.org/timeanddoctor/32/5839_2.png) [@timeanddoctor](https://discourse.slicer.org/u/timeanddoctor)\
**Post date:** [July 17, 2020, 2:10am UTC](https://discourse.slicer.org/t/segmentation-inside-a-roi/12588/2 "2020-07-17T02:10:57Z")

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You can create a croped volume as the ROI volume for the master volume of segment editor.

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**Author:** ![lassoan](https://sea2.discourse-cdn.com/flex002/user_avatar/discourse.slicer.org/lassoan/32/13_2.png) [@lassoan](https://discourse.slicer.org/u/lassoan)\
**Post date:** [July 17, 2020, 7:21pm UTC](https://discourse.slicer.org/t/segmentation-inside-a-roi/12588/3 "2020-07-17T19:21:57Z")

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You can also use masking settings to restrict editing to a certain region, or extract part of a segment that is in a certain region (using Logical operators effect).