# Looking for an efficient approach to isolating a petrosal

**URL:** <https://discourse.slicer.org/t/looking-for-an-efficient-approach-to-isolating-a-petrosal/34769>\
**Category:** Support\
**Tags:** segmentation\
**Created:** [March 8, 2024, 12:18am UTC](https://discourse.slicer.org/t/looking-for-an-efficient-approach-to-isolating-a-petrosal/34769 "2024-03-08T00:18:34Z")\
**Posts on this page:** 1\
**Page:** 1

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**Author:** ![Eddy\_Armstrong](https://sea2.discourse-cdn.com/flex002/user_avatar/discourse.slicer.org/eddy_armstrong/32/69603_2.png) [@Eddy\_Armstrong](https://discourse.slicer.org/u/Eddy_Armstrong)\
**Post date:** [March 8, 2024, 12:18am UTC](https://discourse.slicer.org/t/looking-for-an-efficient-approach-to-isolating-a-petrosal/34769/1 "2024-03-08T00:18:34Z")

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I am trying to isolate the petrosal bone from a CT scan of a fossil skull. I’ve managed to segment it out the hard way before, using threshold and paint.  
But this takes a considerable amount of time, and I always end up with jagged surfaces where the bone closely contacts another or small spikes on what should be a smooth surface. I’ve tried the smoothing tool but it does not seem to change anything, regardless of smoothing method.  
Are there any good techniques or extensions for dealing with such a complex bone?