Dr. Stephen Koch, Director of Radiology at the Lawrence Medical Center in Bronxville, NY, speaks to the issue. He separates out how and why a CT scan is far less dangerous than the radiation from radiation fallout generated by a nuclear reactor.
“I believe there is an incredible amount of social concern about radiation, especially what has happened in the last few months in Japan. It is very important to recognize though the risk versus benefit when a CT scan is appropriate in clinical situation. There is no doubt that a CT scan can be the most sensitive and fastest way to identify a problem and there should be no question that it should be used. Speaking about radiation: There are many different kinds of ionizing radiation, meaning the type of radiation that can get into your body, change the chromosome genetic code and potentially cause a problem - whether it is some sort of abnormality with a specific organ or the development of cancer. These are known risks from radiation exposure.
"However, there is a big difference between X-rays that CT scans use and the type of nuclear fallout that is being experienced in Japan. There, they are concerned about the contaminates - the iodine, the cesium, the hydrogen and the dust that is being released from the reactor. These are fairly big particles, meaning that your body either absorbs them through ingesting it - through water or food sources – or it is inhaled. These particles tend to be absorbed in a specific organ. For instance iodine goes to the thyroid, cesium into the general body. Once lodged there the particle can emit radiation over periods of time causing big problems.
X-rays on the other hand are very high-energy particles, like gamma rays from the sun. 99.999% of X-rays go right through you and causes no problem. So as an overall conclusion: If a CT scan study is clinically warranted and there is a clear benefit, it should be done. Remember - there are different kinds of radiation and not all radiation is created equal. So use common sense.”