# Inaccurate volume measurement

**URL:** <https://discourse.slicer.org/t/inaccurate-volume-measurement/9702>\
**Category:** Support\
**Tags:** segmentation\
**Created:** [January 3, 2020, 1:11pm UTC](https://discourse.slicer.org/t/inaccurate-volume-measurement/9702 "2020-01-03T13:11:21Z")\
**Posts on this page:** 4\
**Page:** 1

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**Author:** ![Hansveerman](https://avatars.discourse-cdn.com/v4/letter/h/9fc29f/32.png) [@Hansveerman](https://discourse.slicer.org/u/Hansveerman)\
**Post date:** [January 3, 2020, 1:11pm UTC](https://discourse.slicer.org/t/inaccurate-volume-measurement/9702/1 "2020-01-03T13:11:21Z")

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Hi all,

I am new to 3Dslicer.  
I loaded prostate MRI images with 3mm slice thickness.  
Then i tried to check the accuracy of the volume measurement option before I did any other calculations.  
When i create spherical structures (40mm and 10mm) with segment editor --\> paint --\> sphere brush, the calculated volumes (segment statistics) are 33272.5mm3 and 530.55mm3. Using 4/3_pi_r^3, the volumes should be 268082mm3 and 4188mm3.  
I can live with a small discrepancy, but this is 8 times too small.

What’s the cause of this difference?

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**Author:** ![Hansveerman](https://avatars.discourse-cdn.com/v4/letter/h/9fc29f/32.png) [@Hansveerman](https://discourse.slicer.org/u/Hansveerman)\
**Post date:** [January 3, 2020, 1:12pm UTC](https://discourse.slicer.org/t/inaccurate-volume-measurement/9702/2 "2020-01-03T13:12:21Z")

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![Vraag aan 3dslicer](https://us1.discourse-cdn.com/flex002/uploads/slicer/original/3X/0/f/0f9310606a0057eeeac50652a6a506cea824cc4a.png)

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**Author:** ![aiden.zhu](https://sea2.discourse-cdn.com/flex002/user_avatar/discourse.slicer.org/aiden.zhu/32/67145_2.png) [@aiden.zhu](https://discourse.slicer.org/u/aiden.zhu)\
**Post date:** [January 3, 2020, 1:39pm UTC](https://discourse.slicer.org/t/inaccurate-volume-measurement/9702/3 "2020-01-03T13:39:29Z")

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Check the diameter or the radius? the difference is 2^3 = 8 times

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<div class="post-metadata">

**Author:** ![Hansveerman](https://avatars.discourse-cdn.com/v4/letter/h/9fc29f/32.png) [@Hansveerman](https://discourse.slicer.org/u/Hansveerman)\
**Post date:** [January 3, 2020, 1:54pm UTC](https://discourse.slicer.org/t/inaccurate-volume-measurement/9702/4 "2020-01-03T13:54:14Z")

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Woops…

2^3 = 8 ran through my head, but I couldn’t figure it out…

Thanks!