CT Scan Radiation Risk Often Underestimated: Study

New research suggests that the majority of people receiving CT scans do not realize how much radiation their body is actually exposed to and underestimate the risk of cancer that may result from the exams.

According to a study published by the medical journal JAMA Internal Medicine on December 31, a survey of patients receiving non-urgent outpatient computed tomography (CT) and cardiac single photon emission computed tomography (SPECT) scans found that nearly nearly 85% of patients underestimated the amount of radiation the tests would expose them to and only about 5% were aware that the scan may increase their risk of developing cancer in the future.

The study involved a survey of 235 patients treated at the University of Washington School of Medicine’s radiology department during February through December 2011. Patients were asked about their knowledge of the medical exams and the amount of radiation exposure, with only 154 patients even indicating that they understood the procedures exposed them to radiation.

Nearly two-thirds of the participants understood the scan would involve radiation but also believed the scan was necessary and would benefit their health. However, only 45 percent said their doctor informed them of the exposure to radiation. More than 90 percent of patients said they were not worried about the radiation emitted from the scan.

Side Effects of CT Scan Radiation Exposure

CT scans are a high powered x-ray that exposes patients to the equivalent of 100 to 500 chest x-rays. The radiation dose from one CT scan can range from a few millisieverts to 20 millisieverts, the yearly exposure limit for employees in the nuclear industry.

While the medical community continues to debate the long term risk of cancer involved with CT scans, a 2009 study conducted by the National Cancer Institute estimated 29,000 future cases of cancer may be caused by CT scans done in 2007 alone. Collectively, Americans received more than 72 million CT scans that year.

The findings of the study follow research showing that there has been an increased use of CT scans over the last 15 years. According to research published in the Journal of the American Medical Association, the use of CT scans and other imaging techniques has tripled and continue to increase nearly 8 percent every year.

Other research has also questioned the benefits provided by many such exams, finding that CT scans are often inefficient at detecting more heart attacks while exposing patients to large unnecessary doses of radiation. In addition, repeated CT scans may triple the risk of cancer for young children. Children are much more sensitive to radiation than adults, increased exposure puts them at increased risk of developing brain cancer, leukemia and other blood and bone cancers.

Many people do not understand that the risk of cancer from radiation can build with increasing exposure to the radiation from additional scans. Researchers urge doctors to discuss the risks and benefits of these tests with patients and to also include radiation exposure as a topic during those discussions.