def get_seed(voxel):
    """ 
    Get a seed point for the center of a brain volume.
  
    Parameters
    ----------
    voxel : tuple: 
        The seed coordinates in x y z.
  
    Returns
    -------
    tuple
        A tuple containing the (x, y, z)-coordinates of the seed.
  
    """
    numpy_seed = (int(voxel[0]), int(voxel[1]), int(voxel[2]))
    sitk_seed = (int(voxel[2]), int(voxel[1]), int(voxel[0]))
    return numpy_seed, sitk_seed