When I saw the keywords in these posts it reminded me of a job I interviewed for. This was in 1991 and the state of the art was to plot iso-dose contours on top of X-ray images, presumably using facts about the beam and the tissues at hand. The plan was to evolve from there to 3D images, possibly rendering these planing data in arbitrary orientations in real time. The link provided above discusses tattooing the patient for future reference and other things, using a machine that was 'similar' to the beam machine but without the beam itself. So it is good to see that planning has moved on in 30 years.