# Error using OpenDose 3D 

**URL:** <https://discourse.slicer.org/t/error-using-opendose-3d/46768>\
**Category:** Support\
**Created:** [April 17, 2026, 1:51pm UTC](https://discourse.slicer.org/t/error-using-opendose-3d/46768 "2026-04-17T13:51:37Z")\
**Posts on this page:** 2\
**Page:** 1

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**Author:** ![Oscar\_Azula](https://sea2.discourse-cdn.com/flex002/user_avatar/discourse.slicer.org/oscar_azula/32/82217_2.png) [@Oscar\_Azula](https://discourse.slicer.org/u/Oscar_Azula)\
**Post date:** [April 17, 2026, 1:51pm UTC](https://discourse.slicer.org/t/error-using-opendose-3d/46768/1 "2026-04-17T13:51:37Z")

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Hello,

I am working with patient images from a Lu-177 therapy study in 3D Slicer. After segmenting the organs and integrating the Absorbed dose rate, I am getting a mass of 0 for all segmented organs.  
I would appreciate any guidance on what might be causing this issue.  
Here are some additional details:  
Imaging modality: SPECT/CT  
Module used for dose calculation: OpenDose  
Version 5.10.0  
From what I understand, mass calculation depends on voxel volume and density (typically from CT Hounsfield Units), so I suspect there may be an issue with missing or incorrect intensity/density information.  
Has anyone encountered this problem before or knows how to fix it?  
Thank you in advance.

 ![1000066076](https://us1.discourse-cdn.com/flex002/uploads/slicer/original/3X/2/d/2d6afd838b6e361013282c766824e5f1f54208ec.jpeg)

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<div class="post-metadata">

**Author:** ![Alex\_Vergara](https://sea2.discourse-cdn.com/flex002/user_avatar/discourse.slicer.org/alex_vergara/32/15205_2.png) [@Alex\_Vergara](https://discourse.slicer.org/u/Alex_Vergara)\
**Post date:** [August 21, 2026, 7:48am UTC](https://discourse.slicer.org/t/error-using-opendose-3d/46768/2 "2026-08-21T07:48:11Z")

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It seems to me that your segmentations are actually delineations. The shell surrounding a volume is not the volume itself. Try converting your segmentations to be binary labelmaps and not closed surfaces as imported from rtstructs. This is a know issue that leads to have 0 mass. Let me know f this is not your case