# A simple circle with a given radius

**URL:** <https://discourse.slicer.org/t/a-simple-circle-with-a-given-radius/36192>\
**Category:** Support\
**Created:** [May 16, 2024, 5:25am UTC](https://discourse.slicer.org/t/a-simple-circle-with-a-given-radius/36192 "2024-05-16T05:25:11Z")\
**Posts on this page:** 2\
**Page:** 1

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**Author:** ![Valeriya](https://avatars.discourse-cdn.com/v4/letter/v/e0b2c6/32.png) [@Valeriya](https://discourse.slicer.org/u/Valeriya)\
**Post date:** [May 16, 2024, 5:25am UTC](https://discourse.slicer.org/t/a-simple-circle-with-a-given-radius/36192/1 "2024-05-16T05:25:11Z")

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Hi!

My issue is the following. I need to be able to create a circle (2D) of a specific radius and place it over a certain region of my MRI image. Ideally I should be able to move this circle with my mouse after creation, but it is also okay if instead I have to pre-define where its center is.  
Is ther any way to do this in slicer? Or if not, is it possible to create a circle in another software and import it into Slicer, but importantly - still being able to place it where I need it to be?

Thank you!

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**Author:** ![chir.set](https://sea2.discourse-cdn.com/flex002/user_avatar/discourse.slicer.org/chir.set/32/66982_2.png) [@chir.set](https://discourse.slicer.org/u/chir.set)\
**Post date:** [May 16, 2024, 8:23am UTC](https://discourse.slicer.org/t/a-simple-circle-with-a-given-radius/36192/2 "2024-05-16T08:23:42Z")

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You can do that with the Shape::Ring object in ‘Projection’ mode, it’s available in the ‘ExtraMarkups’ extension. A ‘Radius’ line is forcibly drawn altogether. If you want to set a determined radius, a few lines of Python code will do that.