CT Scan Radiation - Understand Your Risks

Misinformation abounds about medical imaging radiation exposure.

Children and young adults are more susceptible to the effects of ionizing radiation. It is accepted by the scientific community that it takes approximately 10 to 20 years to develop a radiation-induced malignancy. Folklore and the media, however, create an hysteria around imaging-related radiation exposure that results in a general impression that a CT scan “causes” cancer.  I have watched prominent physicians categorically make comments similar to the following: one in 400 people who undergo a CT scan will get cancer. This kind of statement is misleading, incomplete, inaccurate and is detrimental to the general population.

Based on a 2009 study, published in the Journal of the American Medical Association, the data clearly demonstrated that CT scan radiation dose varied widely depending on the type of scan protocol utilized and the body part that was being evaluated.

The report stated:

“The estimated number of CT scans that will lead to the development of a cancer varied widely depending on the specific type of CT examination and the patient’s age and sex. An estimated 1 in 270 women who underwent CT coronary angiography at age 40 years will develop cancer from that CT scan (1 in 600 men), compared with an estimated 1 in 8100 women who had a routine head CT scan at the same age (1 in 11 080 men). For 20-year-old patients, the risks were approximately doubled, and for 60-year-old patients, they were approximately 50% lower.”

The key to anything is to understand the information given. Here, the report states that a certain type of CT scan, designed to specifically and exclusively evaluate the arteries that supply the heart, results in a risk of cancer of 1 in 270 for a woman and 1 in 600 for a man. Other scans result in a much smaller radiation dose and, hence, a much smaller increased risk of cancer. These are risk estimates. They do not identify which patient will get cancer. Such estimates merely indicate the risk of cancer in the group of people identified. Statistics, unfortunately, are challenging to explain and understand. Consequently, they can also be “spun” by the person making the comments.

The report clearly indicates that there is a risk of cancer related to radiation exposure. It does not, however, state that all CT scans confer an equal risk. The truth is far from it, in fact.

Know your risks. Understand the data. Knowledge is power and fear is overcome through understanding.

When in doubt, ask your radiologist. Your radiologist is the medical provider who has been trained to understand the risks of imaging-related radiation. It is our job to keep the conferred dose to a minimum.  Since the 2009 JAMA study there have been multiple advances in imaging that have resulted in continued decreases in ionizing radiation exposure during CT scans.

Radiology continues to care for patients under the tenet of As Low As Reasonably Achievable. You can count on it.