I agree with Karen that seems like a lot of x-rays. Typically one would receive a full mouth x-ray to check the condition of your teeth (a panorex) maybe some additional bitewings (from the dental perspective) an MRI (which is not an x-ray) and possibly a PET (which is also not an x-ray but does involve a very minute amount of a radioisotope) for triage and/or diagnostic purposes. A CT for radiation therapy planning, and a chest xray as a benchmark. They may have had to repeat some studies because they didn't position you correctly or needed a slightly different angle or perspective. Then they will do a C-arm x-ray for determining best angles of attack with the mask and a x-ray simulation of the treatment protocol on the LINAC.

All of this being a drop in the bucket compared to the x-ray levels you will receive in therapeutic radiation (RT).