Did you know that a CT scan emits at least 50% more radiation than an X-ray? Computed tomography, or CT scans, are performed to look at the internal organs, for instance to see if a person has any brain injuries after an accident. Detailed images of the organs are relayed on computer which gives the doctor a very clear and accurate idea of what is going on. The images are sharper than X-ray images and can produce pictures of organs that cannot be seen on X-ray.
For this reason, CT scans have become one of the most popular diagnostic tools in modern medicine today.
In 2007, 70 million CT scans were performed in America alone. This was up from only 3 million in 1980. But until now, doctors had no idea of the long-term effects of routinely using high levels of radiation on their patients.
Recently, researchers from the University of California studied 1,119 patients who underwent CT scans as part of their care and examined their medical records. They found that "CT scan use makes large contributions to the total cancer risk."
Rates of cancer varied according to the type of scan they had (as some types emit more radiation than others), the age of the patient, and their gender. The younger you are, the more radiation your body absorbs because you have a less effective blood/brain barrier, so children and young people are more at risk.
The researchers found that an estimated one in 270 women and one in 600 men, aged 40, who had a CT scan of the heart would go on to develop cancer.
For CT scans of the head, one in every 8,100 women and one in every 11,080 men would get cancer as a result.
They wrote:
"Overall, we estimated that approximately 29 000 future cancers could be related to CT scans performed in the US in 2007. The largest contributions were from scans of the abdomen and pelvis, chest, and head, as well as from chest CT angiography. One-third of the projected cancers were due to scans performed at the ages of 35 to 54 years compared with 15% due to scans performed at ages younger than 18 years, and 66% were in females."
They also said that the radiation exposure to the general population from CT scans has increased in recent years due to the ever more frequent use of CT scans.
"Efforts need to be undertaken to minimize radiation exposure from CT, including reducing unnecessary studies, reducing the dose per study and reducing the variation in dose across patients and facilities."
They concluded:
"These detailed estimates highlight several areas of CT scan use that make large contributions to the total cancer risk, including several scan types and age groups with a high frequency of use or scans involving relatively high doses, in which risk-reduction efforts may be warranted."
So if you are scheduled to have a CT scan for non-emergency reasons, question your doctor about whether it's really needed. If it is, see if it's possible to have one that uses lower dose radiation or to be scanned for the minimal amount of time.
Source: Arch Intern Med. 2009;169(22):2071-2077.
Joanna is a freelance health writer for The Mother magazine and Suite 101 with a column on infertility, http://infertility.suite101.com/. She is author of the book, 'Breast Milk: A Natural Immunisation,' and co-author of an educational resource on disabled parenting, in addition to running a charity for people damaged by vaccines or medical mistakes.