I found this site pretty interesting. It calculates the increased risk of cancer due to X-Rays taken of your body. Study Gender Age # of exams Dose (mSv) Additional Cancer Risk(%) CT-Brain Male 5 1 2 0.035% CT-Brain Male 7 1 2 0.033% CT-Brain Male 8 1 2 0.032% CT-Brain Male 10 1 2 0.030% CT-Brain Male 12 1 2 0.029% CT-Brain Male 13 1 2 0.028% CT-Brain Male 16 1 2 0.026% CT-Brain Male 18 1 2 0.024% PET CT Male 22 1 14.1 0.154% Head and Neck Angiogram Male 22 1 5 0.055% Plain Film-Pelvis (one view) Male 31 1 0.6 0.005% Plain Film-Dental (two views) Male 32 1 0.01 0.000% Plain Film-Extremity (series) Male 33 1 0.01 0.000% 0.451%