# Is there a way to change the ROI to a sphere

**URL:** <https://discourse.slicer.org/t/is-there-a-way-to-change-the-roi-to-a-sphere/15650>\
**Category:** Feature requests\
**Tags:** markups\
**Created:** [January 25, 2021, 11:10am UTC](https://discourse.slicer.org/t/is-there-a-way-to-change-the-roi-to-a-sphere/15650 "2021-01-25T11:10:44Z")\
**Posts on this page:** 1\
**Showing post:** 6

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**Author:** ![slicer365](https://sea2.discourse-cdn.com/flex002/user_avatar/discourse.slicer.org/slicer365/32/67549_2.png) [@slicer365](https://discourse.slicer.org/u/slicer365)\
**Post date:** [April 28, 2021, 2:41am UTC](https://discourse.slicer.org/t/is-there-a-way-to-change-the-roi-to-a-sphere/15650/6 "2021-04-28T02:41:07Z")

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For example, brain surgery incisions are often oval or irregular. If I use a cube ROI, this kind of simulated incision is not very realistic. In addition, we hope that the area inside the ROI can be hidden, so that the internal situation can be seen in real time. Of course, this function can be achieved through PRISM，This function is really necessary for many neurosurgeons.Currently we are more dependent on Volume Rendering than PRISM.  
Just like the picture above, if I want to make a circular surgical skull incision, there are many methods, but my purpose is to hide the skull inside ROI so that I can observe the internal structure of the skull. However, currently ROI is to show the selected area instead of hiding it.

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