Robin waffling

Monday morning (before chemo started) Robin went for Radiation Therapy (RT) and the technician mounted the mask over her face. Robin noticed it didn't feel right (it was pinching her cheek and forehead) - the technician quickly realized the mistake and fixed the position. We need Robin's head to be in the exact same position each day because the precision of the radiation beams is greater than a tenth of an inch. The highest radiation dose is intended to hit the tumor with lesser doses passing through healthy tissue. It's analogous to pointing six flashlights from different directions onto one spot in the bottom of a swimming pool. Imagine being able to see each of the six different beams passing through the water, and where the beams meet on the bottom there would be one very brightly lit spot. In the same way, Robin's tumor is the focal point for the radiation but much of her head and neck get some lesser amount of exposure (in this example, one sixth of the level which hits the tumor). Essentially it is just more "friendly fire" misery, just like the in the world of chemo drugs.

Even with the mask properly positioned it fits tightly which you can see from the waffle pattern on her forehead (and the tip of her nose) seen just after emerging from RT: