# Load PET.reg.lta freesurfer corregistration file in 3D slicer 4.11

**URL:** <https://discourse.slicer.org/t/load-pet-reg-lta-freesurfer-corregistration-file-in-3d-slicer-4-11/23616>\
**Category:** Support\
**Created:** [May 27, 2022, 10:14pm UTC](https://discourse.slicer.org/t/load-pet-reg-lta-freesurfer-corregistration-file-in-3d-slicer-4-11/23616 "2022-05-27T22:14:42Z")\
**Posts on this page:** 3\
**Page:** 1

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**Author:** ![Gonzalo\_Rojas\_Costa](https://sea2.discourse-cdn.com/flex002/user_avatar/discourse.slicer.org/gonzalo_rojas_costa/32/5259_2.png) [@Gonzalo\_Rojas\_Costa](https://discourse.slicer.org/u/Gonzalo_Rojas_Costa)\
**Post date:** [May 27, 2022, 10:14pm UTC](https://discourse.slicer.org/t/load-pet-reg-lta-freesurfer-corregistration-file-in-3d-slicer-4-11/23616/1 "2022-05-27T22:14:42Z")

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Hi:  
I corregistered a PET file to a freesurfer data using mri\_coreg command. I imported the freesurfer-generated data to 3D Slicer. How can I import the PET.reg.lta file in 3D Slicer?

Sincerely,

Gonzalo Rojas Costa

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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:** [May 28, 2022, 12:26am UTC](https://discourse.slicer.org/t/load-pet-reg-lta-freesurfer-corregistration-file-in-3d-slicer-4-11/23616/2 "2022-05-28T00:26:13Z")

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You should be able to convert the [.reg.lta linear transform](https://surfer.nmr.mgh.harvard.edu/fswiki/FsTutorial/LtaFormat) to an ITK transform. Slicer can read the ITK transform and you can apply it to the PET image.

It seems that [nitransforms](https://github.com/nipy/nitransforms/) can do the lta to ITK transform file conversion.

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**Author:** ![Gonzalo\_Rojas\_Costa](https://sea2.discourse-cdn.com/flex002/user_avatar/discourse.slicer.org/gonzalo_rojas_costa/32/5259_2.png) [@Gonzalo\_Rojas\_Costa](https://discourse.slicer.org/u/Gonzalo_Rojas_Costa)\
**Post date:** [May 31, 2022, 6:24pm UTC](https://discourse.slicer.org/t/load-pet-reg-lta-freesurfer-corregistration-file-in-3d-slicer-4-11/23616/3 "2022-05-31T18:24:05Z")

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I couldn’t install the nitransforms. Would there be another software that performs the same conversion (.reg.lta linear transform to ITK)?