# Transformation matrix in B spline Deformable registration module

**URL:** <https://discourse.slicer.org/t/transformation-matrix-in-b-spline-deformable-registration-module/43488>\
**Category:** Support\
**Created:** [June 25, 2025, 1:34pm UTC](https://discourse.slicer.org/t/transformation-matrix-in-b-spline-deformable-registration-module/43488 "2025-06-25T13:34:19Z")\
**Posts on this page:** 1\
**Page:** 1

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**Author:** ![azam](https://avatars.discourse-cdn.com/v4/letter/a/ea666f/32.png) [@azam](https://discourse.slicer.org/u/azam)\
**Post date:** [June 25, 2025, 1:34pm UTC](https://discourse.slicer.org/t/transformation-matrix-in-b-spline-deformable-registration-module/43488/1 "2025-06-25T13:34:19Z")

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Hi everyone  
I have two DICOM CT images (CT1, CT2) (Matrix size: 512,512,111) that I want to register them with B spline deformable registration module. I have also exported a RT dose file (RT2) (Matrix size:100,61,1) from the treatment planning system. I want to apply the transformation matrix of this registration to the RT dose file. But I don’t know how can I do it.  
1- Can you help me how to do this?  
2- Do I need to change the size of the RT dose file in general?

Tanks a lot