# Crop regions outside the radiation field of the DRR image

**URL:** <https://discourse.slicer.org/t/crop-regions-outside-the-radiation-field-of-the-drr-image/20512>\
**Category:** Support\
**Created:** [November 7, 2021, 12:43pm UTC](https://discourse.slicer.org/t/crop-regions-outside-the-radiation-field-of-the-drr-image/20512 "2021-11-07T12:43:03Z")\
**Posts on this page:** 3\
**Page:** 1

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**Author:** ![shahrokh](https://sea2.discourse-cdn.com/flex002/user_avatar/discourse.slicer.org/shahrokh/32/1499_2.png) [@shahrokh](https://discourse.slicer.org/u/shahrokh)\
**Post date:** [November 7, 2021, 12:43pm UTC](https://discourse.slicer.org/t/crop-regions-outside-the-radiation-field-of-the-drr-image/20512/1 "2021-11-07T12:43:03Z")

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Dear Users and Developers

I want to crop DRR image with the Beam. To be more precise, I want to do the following steps:

1- Loading the DRR image taken from the TPS system (for example, **RTIMAGE** related to **Med Tangent** radiation field);  
2- Loading RTPlan (for example, including as **Med Tangent** radiation field)  
3- Cutting a part of the DRR image that is outside the radiation field (zeroing this region).  
Can you give me some guidance?

Best regards.  
Shahrokh

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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:** [November 8, 2021, 2:27am UTC](https://discourse.slicer.org/t/crop-regions-outside-the-radiation-field-of-the-drr-image/20512/2 "2021-11-08T02:27:09Z")

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Since beams are special model nodes, it is very easy to mask volumes with them:

- select the volume that you want to mask (blank out regions from it) as background volume
- go to the Segment Editor module to create a segmentation node
- go to the Segmentations module and import the beam as a segment, using Export/import… → Import → Models
- go to Segment Editor module and use Mask volume to blank out the volume outside the segment

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**Author:** ![shahrokh](https://sea2.discourse-cdn.com/flex002/user_avatar/discourse.slicer.org/shahrokh/32/1499_2.png) [@shahrokh](https://discourse.slicer.org/u/shahrokh)\
**Post date:** [November 9, 2021, 1:21pm UTC](https://discourse.slicer.org/t/crop-regions-outside-the-radiation-field-of-the-drr-image/20512/3 "2021-11-09T13:21:26Z")

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Dear Andras

Thanks a lot for your guidance.  
I can do it.

Best regards.  
Shahrokh