Slope and intercept for pixel intensity MRI

I want to use 3D slicer to extract first order features with the radiomics module from RTstructs of MRI images. However, I want all the pixel intensities from my MR image to be adapted first by a certain slope and intercept before I extract the features. If this is possible in 3D slicer, how would I be able to do this?
Thank you in advance!

You can just access the pixels as a numpy array and manipulate them as you see fit before running radiomics.