How to apply a segmented tumor to other imaging

Hi, everyone.

I finished a tumor segmentation from T2-flair imaging and created the output as .nrrd file.
Since segmenting all images is time consuming, I want to apply the nrrd file to also other image modalities. How can I do this in the 3D slicer?

You can register the source image that you used for segmentation to any other image. You can then apply the computed transform to the segmentation.