Help with 3d nnUNet and OCT images

[CastingSpell]

Hey there I havent seen anything like this in the docu (if you have, please share with me). Could you give me some advise to face the problem. I've seen nnUnet processes the images getting like slides of them, so the folder structure is something like xxx_image_slice.nifti.tiff. But those images go to the network one by one. What if I want to feed the nn with 100 tomographies, how do I need to sort the elements in order to make nnUNet work properly?

Thanks in advance!

[CastingSpell]

Ok, I need to conver the images to nifti format and then I should be good to go with the training