# Calculating difference in dose between two CT scans

**URL:** <https://discourse.slicer.org/t/calculating-difference-in-dose-between-two-ct-scans/46047>\
**Category:** Support\
**Created:** [February 3, 2026, 3:34pm UTC](https://discourse.slicer.org/t/calculating-difference-in-dose-between-two-ct-scans/46047 "2026-02-03T15:34:54Z")\
**Posts on this page:** 4\
**Page:** 1

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**Author:** ![hanginghats](https://avatars.discourse-cdn.com/v4/letter/h/f6c823/32.png) [@hanginghats](https://discourse.slicer.org/u/hanginghats)\
**Post date:** [February 3, 2026, 3:34pm UTC](https://discourse.slicer.org/t/calculating-difference-in-dose-between-two-ct-scans/46047/1 "2026-02-03T15:34:54Z")

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I’m doing a project which requires me to analyse the difference in dose between two identical CT scans reconstructed with different algorithms. Is there any way for me to do this with slicer and slicerRT?

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**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:** [February 5, 2026, 9:25am UTC](https://discourse.slicer.org/t/calculating-difference-in-dose-between-two-ct-scans/46047/2 "2026-02-05T09:25:03Z")

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We need more information. You don’t mention radiotherapy anywhere, so first question would be CT dose or RT dose? Please elaborate as much as possible, what kind of data do you have, what kind of comparison you want to do… Thanks.

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**Author:** ![hanginghats](https://avatars.discourse-cdn.com/v4/letter/h/f6c823/32.png) [@hanginghats](https://discourse.slicer.org/u/hanginghats)\
**Post date:** [February 13, 2026, 6:22am UTC](https://discourse.slicer.org/t/calculating-difference-in-dose-between-two-ct-scans/46047/3 "2026-02-13T06:22:07Z")

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I have RT dose, exported from varian eclipse TPS. I have the doses calculated using two different imaging systems and want to compare the obtained doses to ensure no big difference between them.

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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:** [February 14, 2026, 5:11am UTC](https://discourse.slicer.org/t/calculating-difference-in-dose-between-two-ct-scans/46047/4 "2026-02-14T05:11:02Z")

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After you install SlicerRT extension, you can load the dose volumes and compare them using Dose Comparison module.