# Display issue with RT structs and MR volume

**URL:** <https://discourse.slicer.org/t/display-issue-with-rt-structs-and-mr-volume/546>\
**Category:** Support\
**Tags:** slicerrt\
**Created:** [June 21, 2017, 1:40pm UTC](https://discourse.slicer.org/t/display-issue-with-rt-structs-and-mr-volume/546 "2017-06-21T13:40:18Z")\
**Posts on this page:** 1\
**Showing post:** 10

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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:** [June 23, 2017, 1:26pm UTC](https://discourse.slicer.org/t/display-issue-with-rt-structs-and-mr-volume/546/10 "2017-06-23T13:26:55Z")

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Having multiple contours in the same slice in the same structure does not seem to be valid. [DICOM standard Part 3 C. 8.8.6](http://dicom.nema.org/dicom/2013/output/chtml/part03/sect_C.8.html#sect_C.8.8.6) does not explicitly say that intersection is prohibited, but “closed contour (polygon) containing coplanar points” indicates that a simple polygon is expected. It is explicitly stated that you cannot even make a hole in a polygon (you need to use keyhole technique instead).

Did you draw multiple contours in the same slice in the same structure in the treatment planning system? Or you have distinct contours in the treatment planning system but they show up at the same slice in Slicer?

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_[View the full topic](https://discourse.slicer.org/t/display-issue-with-rt-structs-and-mr-volume/546)._