Just FYI, In addition to being a care giver, I happen to be a nuclear medicine technologist and current radiation safety officer at the community hospital where I work. We use the ALARA principle ("As low as reasonably achievable" when it comes to any radiation for our patients or employees.)
PET (positron emission tomography) also gives off ionizing radiation (2- 511 KEv gamma rays). So, that should be included in your list of exams too. Good advice to be prudent when ever undergoing any procedure involving radiation. Your Radiation therapist should be using positive Identification procedures for each and every treatment.(PS Dental xrays give off alot of radiation also. Gary, may I suggest changing your statement to "Dental and chest x-rays are a smallER amount of radiation"? For dental, be sure they cover you with a lead apron. )