# Generate DRRs from a 3DCT. Distance paramters in Python

**URL:** <https://discourse.slicer.org/t/generate-drrs-from-a-3dct-distance-paramters-in-python/44868>\
**Category:** Support\
**Tags:** slicerrt\
**Created:** [October 24, 2025, 12:54pm UTC](https://discourse.slicer.org/t/generate-drrs-from-a-3dct-distance-paramters-in-python/44868 "2025-10-24T12:54:33Z")\
**Posts on this page:** 3\
**Page:** 1

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**Author:** ![ruju](https://avatars.discourse-cdn.com/v4/letter/r/ea666f/32.png) [@ruju](https://discourse.slicer.org/u/ruju)\
**Post date:** [October 24, 2025, 12:54pm UTC](https://discourse.slicer.org/t/generate-drrs-from-a-3dct-distance-paramters-in-python/44868/1 "2025-10-24T12:54:33Z")

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Hi,

I have another question about the computation of DRRs in 3D slicer. In the GUI of the DRR Image Computation module I can change the isocenter to imager distance. Is it also possible to modify this parameter in a Python script? I haven’t found any command that works in 3D Slicer 5.8.1 so far.

Thanks in advance!

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<div class="post-metadata">

**Author:** ![Mik](https://avatars.discourse-cdn.com/v4/letter/m/958977/32.png) [@Mik](https://discourse.slicer.org/u/Mik)\
**Post date:** [October 24, 2025, 2:22pm UTC](https://discourse.slicer.org/t/generate-drrs-from-a-3dct-distance-paramters-in-python/44868/2 "2025-10-24T14:22:27Z")

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That`s the DrrImageCompulationNode parameter:

Examples:

```auto
# DRR image in isocenter plan
# Set isocenter imager distance == 0 mm
rtImageParameters.SetIsocenterImagerDistance(0)

```

```auto
# Set isocenter imager distance == 350 mm
rtImageParameters.SetIsocenterImagerDistance(350)

```

You should see how images markups change their position as well.

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<div class="post-metadata">

**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:** [October 25, 2025, 2:00pm UTC](https://discourse.slicer.org/t/generate-drrs-from-a-3dct-distance-paramters-in-python/44868/3 "2025-10-25T14:00:34Z")

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>
> Congratulations Yuval Barak-Corren, Matt Daemer, Andras Lasso, Kyle Sunderland and team on the their publication in the Journal for the Society for Cardiovascular Angiography & Interventions describing the SlicerHeart Virtual Cath...