The 70 million CT scans peformed in 2007 are expected to cause 29,000 new cancers that will kill 15,000 Americans . This data was recently published in the medical journal Archives of Internal Medicine.
CT scans are performed for a variety of reasons, and allow much more detailed information about the human body to be obtained. In some cases, they may prevent the need for exploratory surgery or unnescessary treatments. But CT scans involve much higher radiation dose than conventional X-rays. A chest CT scan exposes the patient to more than 100 times the radiation dose of a chest X-ray.
Things you can do if you are going to receive a CT scan (or any other test involving radiation)
Ask your doctor about the comparative risk of the scan, compared to the risk of your condition
Inquire about alternative tests that could be used.
Different systems vary widely in the amount of raditaion they produce...ask your doctor if a lower-dose sysem is available.
Ask if and how your treatment will be changed as a result of the scan
Equipment makers like GE and Toshiba are working on lower-radiation systems that still offer doctors the clarity they need. Meanwhile, other technology like MRI are also being improved to look at the body's bones, an area where X-rays still offer an advantage.
As a surgeon, the scans I order directly affect my plans and actions at the time of surgery, however I will definitely be much more aware of the risks before ordering future scans. My training took place before CT scans were widely available. Back then, we relied on our ears, eyes, hands, and experience to make a diagnosis.
Personally, I wouldn't mind seeing medicine go back to that.