Makes sense; thanks. I'm out of my depth but it seems neurosurgery may just have it easier here, being able to fix a rigid stereotaxy head frame and fiducial markers across both imaging and therapy. Not to mention less tissue deformation enabling a gamma knife intersection-of-beams approach (i.e. ~200 collimated, mm-wide gamma sources).

Not to be glib but on behalf of the thousands of people going into a radiotherapy clinic today for treatment, thanks for working to improve these techniques.