HounsField Units for CT scans

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.

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.

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?

Yes, that is correct.

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Thank you so much! This has been very helpful.