# Gantry tilt correction in CT DICOMS

**URL:** <https://discourse.slicer.org/t/gantry-tilt-correction-in-ct-dicoms/19443>\
**Category:** Support\
**Tags:** dicom\
**Created:** [August 31, 2021, 6:11pm UTC](https://discourse.slicer.org/t/gantry-tilt-correction-in-ct-dicoms/19443 "2021-08-31T18:11:25Z")\
**Posts on this page:** 4\
**Page:** 1

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**Author:** ![Sharada](https://avatars.discourse-cdn.com/v4/letter/s/ba8739/32.png) [@Sharada](https://discourse.slicer.org/u/Sharada)\
**Post date:** [August 31, 2021, 6:11pm UTC](https://discourse.slicer.org/t/gantry-tilt-correction-in-ct-dicoms/19443/1 "2021-08-31T18:11:25Z")

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Hello,

I am working on gantry tilt correction for CT images and was directed to 3D Slicer through Steve Pieper’s comment [here](https://discourse.vtk.org/t/correcting-the-gantry-tilt-in-ct-scans/5526/4). And I have run into the following issues -

1. According to the [documentation](https://slicer.readthedocs.io/en/latest/user_guide/modules/dicom.html?highlight=tilt#panels-and-their-use), there should be an option to choose the plugins that examine a series while being imported. I am using Slicer 4.11 and don’t see that option.

2. I inferred from [here](https://github.com/Slicer/Slicer/commit/3328b81211cb2e9ae16a0b49097744171c8c71c0) that the module “DICOMScalarVolumePlugin” accounts for gantry tilt and irregular slice spacing correction and made sure it is checked as a loaded module. But when I try to click on it after loading my (uncorrected) images, nothing happens.

Can someone please help with this? How do I go about correcting gantry tilted CT images with Slicer?  
Thanks in advance!

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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:** [August 31, 2021, 6:18pm UTC](https://discourse.slicer.org/t/gantry-tilt-correction-in-ct-dicoms/19443/2 "2021-08-31T18:18:41Z")

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You need to enable [“Acquisition geometry regularization”](https://slicer.readthedocs.io/en/latest/user_guide/modules/dicom.html#basic-usage) in application settings before you load the data set.

The plugin selector is on the left (“DICOM plugins” section), but you don’t need to touch those settings, as Scalar Volume plugin is enabled by default.

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**Author:** ![Sharada](https://avatars.discourse-cdn.com/v4/letter/s/ba8739/32.png) [@Sharada](https://discourse.slicer.org/u/Sharada)\
**Post date:** [August 31, 2021, 7:00pm UTC](https://discourse.slicer.org/t/gantry-tilt-correction-in-ct-dicoms/19443/3 "2021-08-31T19:00:48Z")

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Hi Andras,

I had enabled that before I attempted to load the DICOM images. I followed your comment [here](https://discourse.slicer.org/t/actual-size-of-stl-models/5005/17).

1. When I load my images through the “DCM” module, I cannot even see my image volumes. I am not sure why this is happening? But this creates a transform which allows me to go to ‘Transform Hierarchy \> Harden Transform’
2. When I load it through “Data” module, I see the image volumes, but the view is not corrected. And this does not create a transform.  
Please see below - the following image was obtained at a gantry tilt of +21.5 degrees.  
 ![image](https://us1.discourse-cdn.com/flex002/uploads/slicer/original/3X/f/1/f1b7665c4cf2868cfc25c500b2d9e3bbb45bcfa5.jpeg)

Please advise!

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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:** [August 31, 2021, 7:09pm UTC](https://discourse.slicer.org/t/gantry-tilt-correction-in-ct-dicoms/19443/4 "2021-08-31T19:09:18Z")

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You need to use the DICOM module for loading images. Click [“Reset field of view” button](https://slicer.readthedocs.io/en/latest/user_guide/user_interface.html#slice-view) to make sure your volume is in the field of view.