Most human exposure to radiation is from medical procedures such as X-rays, CT scans, and mammograms. Radiation can be measured in a unit known as millirems. The According to the U.S. Nuclear Regulatory Committee, the average American is exposed to 620 millirems of radiation, with 310 miilirems coming from the environment. If you receive a whole body CT scan, you receive 1000 millirems of radiation, which is much more than the yearly exposure. Get a CT scan of the chest and you received 700 millirems, again more than the yearly dose. Dental x-rays? Well, they only give you 1.5 millirems. However, there is level of radiation that is technically “safe” since the health effects of radiation are cumulative. That is, the more radiation you are exposed to, the worse of an effect it has on your health.
So, there is some degree of radiation exposure you will get no matter what. But why expose yourself to any extra radiation? One source of needless radiation you can avoid are full body scanners at airports. These are known as backscatter scanners. It had traditionally been thought that these scanner expose you to very low levels of radiation (e.g., .005 to .01 millirems). The Transportation Safety Administration insists this level is safe (e.g., 1000 such scans is equal to 1 chest x-ray) , but the non-profit investigative journalism organization, ProPublica, insists that the U.S. government glossed over cancer concerns as it rolled out these scanners and that the radiation exposure level is much higher. Researchers at Columbia University have said that the machines emit 20 times more radiation that originally estimated. The Inter-Agency Committee on Radiation Safety indicated that pregnant women and children are particularly at risk by these scanners.
On 11/14/11, the European commission announced new policy that they would ban these types of scanners due to concerns about health and safety. Instead of using X-ray scanners, they are replacing them with millimeter-waver scanners, which use low energy radio waves. Due to the low energy, these scanners do not have the power to cause genetic mutations and thus should not cause cancer. On 11/21/11, the head of the TSA reneged on his prior plan to re-study the safety of the scanners, stating they were safe. Not being a radiation expert, I really don’t know who is right. But I do know that I can at least opt out of these scans and that is what I did the last time I went to the airport. The result is a pat down but I found the whole experience easy to deal with. At least I know did not expose myself and my family to needless radiation. And just in case you were wondering, metal detectors at the airports do not expose you to x-rays or damaging forms of radiation.