# 3D-2D CT-Fluoro registration

**URL:** <https://discourse.slicer.org/t/3d-2d-ct-fluoro-registration/29105>\
**Category:** Support\
**Created:** [April 25, 2023, 6:01am UTC](https://discourse.slicer.org/t/3d-2d-ct-fluoro-registration/29105 "2023-04-25T06:01:50Z")\
**Posts on this page:** 1\
**Page:** 1

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**Author:** ![BraveDistribution](https://sea2.discourse-cdn.com/flex002/user_avatar/discourse.slicer.org/bravedistribution/32/14564_2.png) [@BraveDistribution](https://discourse.slicer.org/u/BraveDistribution)\
**Post date:** [April 25, 2023, 6:01am UTC](https://discourse.slicer.org/t/3d-2d-ct-fluoro-registration/29105/1 "2023-04-25T06:01:50Z")

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Hello community,

I would like to perform 3D-2D registration (CT-fluoroscopy) on pelvis data from the GitHub repository [GitHub - rg2/Regi2D3D-IPCAI2020: Code for the registration component of the IPCAI 2020 paper: "Automatic Annotation of Hip Anatomy in Fluoroscopy for Robust and Efficient 2D/3D Registration." https://arxiv.org/abs/1911.07042 or https://doi.org/10.1007/s11548-020-02162-7](https://github.com/rg2/Regi2D3D-IPCAI2020).

I have some assumptions on how to perform the registration:

1. Create DRR - I can achieve that with [GitHub - arcadelab/deepdrr: Code for "DeepDRR: A Catalyst for Machine Learning in Fluoroscopy-guided Procedures". https://arxiv.org/abs/1803.08606](https://github.com/arcadelab/deepdrr).
2. Compare two images to obtain the NCC loss (DRR, fluoroscopy).
3. Optimize the transformation and rotation matrix to minimize loss. At the moment, I can use some nature-inspired algorithm since this is a proof of concept and real-time capability is not necessary yet.

I have read @lassoan’s answers from both [Get projection plane in 2D-3D Registration](https://discourse.slicer.org/t/get-projection-plane-in-2d-3d-registration/26023) and [Get projection plane in 2D-3D Registration](https://discourse.slicer.org/t/get-projection-plane-in-2d-3d-registration/26023).

> 2D/3D registration is a challenging problem. You need to set the initial pose close to the solution, but there may be other tricks as well.

If I want to get the initial pose close to the solution, can I perform manual registration via some fiducials in 3DSlicer? If yes, could you please tell me how?

Thanks