# HounsField Units for CT scans
**URL:** https://discourse.slicer.org/t/hounsfield-units-for-ct-scans/33668
**Category:** Support
**Created:** [January 8, 2024, 12:24pm UTC](https://discourse.slicer.org/t/hounsfield-units-for-ct-scans/33668 "2024-01-08T12:24:04Z")
**Posts on this page:** 6
**Page:** 1
### Author:  [@Varsha](https://discourse.slicer.org/u/Varsha)
#### Post date: [January 8, 2024, 12:24pm UTC](https://discourse.slicer.org/t/hounsfield-units-for-ct-scans/33668/1 "2024-01-08T12:24:05Z")
Hi. I am trying to select a range of HU to work with my CT images (primarily because I want to visualise trabecular changes of the bone). Is selecting a threshold under “Segment Editor” the same as setting an HU range? Or is there a separate way to set this range. For example., I require an HU range of -150 to +1000. How should I go about doing this? Any help would be appreciated.
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### Author:  [@hherhold](https://discourse.slicer.org/u/hherhold)
#### Post date: [January 8, 2024, 12:37pm UTC](https://discourse.slicer.org/t/hounsfield-units-for-ct-scans/33668/2 "2024-01-08T12:37:23Z")
The range of values in Segment Editor (and throughout Slicer) is whatever the absorbance values are in your volume - for a micro-CT volume, for example, a 16-bit scan would be 0-65535. For a medical CT scanner, those values would be in Hounsfeld units, so those are the values you would use when setting a threshold.
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### Author:  [@Varsha](https://discourse.slicer.org/u/Varsha)
#### Post date: [January 8, 2024, 1:13pm UTC](https://discourse.slicer.org/t/hounsfield-units-for-ct-scans/33668/3 "2024-01-08T13:13:00Z")
Hi. Thank you so much for this. So it is my understanding that if I select a Threshold of -150 to +1000 under “Segment Editor” this is the same as setting an HU range of \_150 to +1000?
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### Author:  [@hherhold](https://discourse.slicer.org/u/hherhold)
#### Post date: [January 8, 2024, 4:37pm UTC](https://discourse.slicer.org/t/hounsfield-units-for-ct-scans/33668/4 "2024-01-08T16:37:25Z")
Yes, that is correct.
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### Author:  [@Varsha](https://discourse.slicer.org/u/Varsha)
#### Post date: [January 9, 2024, 8:56am UTC](https://discourse.slicer.org/t/hounsfield-units-for-ct-scans/33668/5 "2024-01-09T08:56:01Z")
Thank you so much! This has been very helpful.
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### Author:  [@Danilo\_Borja](https://discourse.slicer.org/u/Danilo_Borja)
#### Post date: [August 8, 2024, 1:34pm UTC](https://discourse.slicer.org/t/hounsfield-units-for-ct-scans/33668/6 "2024-08-08T13:34:06Z")
hello Varsha im looking to do same, in mandibular condyle pre post surgery can you please share the way yo do ti ?