The dental impression which is bolted to the head ring.

Oblique view of the head ring and straps. The plastic is to keep Val's hair
out of the occipital mold, which is hardening at this point. Note the IV port
ready for the iodine contrast agent. She  is leaning forward as instructed to
keep the table registration pins at the back of the ring from hitting her and
changing the position of the ring as the mold material hardens.
She was also very tired and nervous.

Here the setup technician is taking the first set of measurements to Val's skull
to verify the headgear positioning.

Val getting the iodine contrast agent, just before the effects hit her.

The imaging technician sits in the C T scan instrument as he takes the third set of verification measurements, just before he took off the clear dome helmet and latched on the image registration ring. It is sitting on the desk in front of the female technician recording the measurements.   Val wore the ring during the imaging process so the aiming of the LINAC radiosurgery instrument can be precisely correlated with the images.