# New extension: RadReirradiation for radiotherapy reirradiation analysis and EQD2 dose accumulation

**URL:** <https://discourse.slicer.org/t/new-extension-radreirradiation-for-radiotherapy-reirradiation-analysis-and-eqd2-dose-accumulation/47028>\
**Category:** Support\
**Tags:** registration, extensions-manager, python, radiotherapy\
**Created:** [May 14, 2026, 2:23pm UTC](https://discourse.slicer.org/t/new-extension-radreirradiation-for-radiotherapy-reirradiation-analysis-and-eqd2-dose-accumulation/47028 "2026-05-14T14:23:00Z")\
**Posts on this page:** 1\
**Page:** 1

<div class="post-metadata">

**Author:** ![LuisParedesOcampo](https://sea2.discourse-cdn.com/flex002/user_avatar/discourse.slicer.org/luisparedesocampo/32/82110_2.png) [@LuisParedesOcampo](https://discourse.slicer.org/u/LuisParedesOcampo)\
**Post date:** [May 14, 2026, 2:23pm UTC](https://discourse.slicer.org/t/new-extension-radreirradiation-for-radiotherapy-reirradiation-analysis-and-eqd2-dose-accumulation/47028/1 "2026-05-14T14:23:00Z")

</div>

Hi everyone,

I’d like to introduce RadReirradiation, a new 3D Slicer extension designed to support clinical reirradiation workflows in radiotherapy.

The extension provides the following features:

• Voxel-by-voxel BED and EQD2 biological dose accumulation, with time-based recovery factors based on the linear-quadratic model.  
• An image registration wrapper (Rigid, Affine, and Deformable B-Spline) built on the BRAINSFit engine, with an interactive manual pre-alignment panel and an Auto-Center tool specifically designed to handle CBCT field-of-view discrepancies common in linac-based imaging.  
• Automatic resampling of the moving dose grid to match the reference geometry prior to biological accumulation.  
• A custom Eclipse-style dose wash colormap (Dark Blue to Red, 2 Gy threshold) for familiar TPS-like visualization.

The extension is implemented in Python, depends on SlicerRT, and has been tested in research scenarios at our institution.

The repository is available at: [https://github.com/LuisParedesOcampo/SlicerRadReirradiation](https://github.com/LuisParedesOcampo/SlicerRadReirradiation)

A web-based companion tool is also available at [https://radcomp.streamlit.app](https://radcomp.streamlit.app)

Feedback, suggestions, and contributions are very welcome!

Best regards,  
Luis Paredes - Medical Physicist, Cali, Colombia