NEW YORK: One-third of people getting a CT scan didn't know the test exposed their body to radiation, in a new study from a single US medical center.
Researchers found the majority of patients also underestimated the amount of radiation delivered by a CT scan, and just one in 20 believed the scan would increase their chance of ever getting cancer.
The study's lead researcher, Janet Busey, said doctors need to do a better job of talking to patients about the risks and benefits of the tests, including about radiation exposure.
One challenge is that there is still debate within the medical community about just how much long term cancer risk the scans carry, she said. That risk also depends on how many scans a patient gets and which organs are exposed to radiation.
"There's no doubt, CT saves lives," Busey, from the University of Washington in Seattle, told Reuters Health. And their benefits usually outweigh their risks, she added.
Still, even if the radiation risk is small, patients "definitely should be aware of it."
CT scans are high-powered X-rays that provide clearer images but expose patients to between ten and 100 times more radiation than a normal head or chest X-ray, for example.
Busey said from their earlier studies, she and her colleagues learned anecdotally that many patients didn't know much about CT scans. So they surveyed 235 people who were having a non-emergency scan, for example to check a cancer's spread or to look into symptoms such as shortness of breath.
Those scans included CTs as well as another type of imaging, known as single photon emission computed tomography, or SPECT scans.
Two-thirds of the patients believed their scan was definitely necessary and would benefit their health, and 84 percent said their doctors had explained the reason for the scan.
Another two-thirds of the patients understood CT scans involve radiation, but less than half of those had learned about radiation risks from their doctor.