On average, we are all exposed to about 3 millisieverts of radiation a year from natural sources, such as the Earth’s radon gas, and the Universe’s cosmic rays. Experts recommend that the public receive less than 4 millisierverts total a year. However, they do not include medical procedures in that limit because the procedures may bring health benefits. Here’s a list of common sources of radiation that we receive:
Natural background (U.S.) per year: 3.1
Airport scanner (backscatter method): 0.0001
Natural gas cooking per year: 0.0004
Arm x-ray: 0.001
Bone density x-ray: 0.001
Highway travel per year: 0.004
Dental x-ray: 0.005
Domestic airline flight (five hours): 0.017
Smoking one pack of cigarettes per day for a year: 0.36
Mammogram: 0.4
Fukushima emergency workers per hour: 1.0
Brain CT scan: 2.0
Thyroid scan (nuclear medicine): 4.8
Brain scan(nuclear medicine): 6.9
Pelvis CT scan: 10
Coronary CT angiography: 16
Astronaut on space station for one year: 72
Healthfacts.blog 