Many patients and direct caregivers have little to no knowledge about the use of ionizing radiation in diagnostic imaging, according to a recent study published by the Journal of the American College of Radiology.

Joseph R. Steele, MD, University of Texas MD Anderson Cancer Center in Houston, and colleagues emailed a survey about ionizing radiation to more than 48,000 randomly selected patients who had undergone an imaging exam from Nov. 1, 2013, to Jan. 31, 2014. More than 5,000 patients completed the survey, and a second survey, which was considerably shorter, was then sent to patients who had never opened the first survey. More than 3,000 patients responded to that second survey.

Overall, the data revealed that more than 21 percent of respondents said they could define ionizing radiation. More than 35 percent correctly said CT used ionizing radiation, and more than 29 percent incorrectly said MRI used ionizing radiation.

“The results of our study suggest a need for immediate educational efforts targeted at patients undergoing oncologic diagnostic imaging procedures, and their caregivers,” the authors wrote. “As radiology seeks to demonstrate its value in the developing health care marketplace, this educational effort may offer much opportunity.”

Steele et al. said these survey results are especially noteworthy because the respondents had all recently undergone exams themselves.

“Although this lack of understanding might be acceptable among healthy individuals who have never undergone an imaging procedure, our study population had undergone a mean of 8.8 imaging procedures during the previous three-year period,” the authors wrote. “Further, our study population was highly educated—a previous internal survey of the population at our center showed that the education level is much higher than that of the US population in general.”

The data also showed that more than 12 percent of respondents incorrectly said heritable mutations were a risk of CT scans, and more than 23 percent incorrectly said sterility was a risk associated with CT scans of the abdomen and pelvis.

The authors said “most past and current patient education efforts” related to radiation used in medical imaging have focused on the risk of cancer, but this survey shows that mutations and sterility must also be addressed.

“The survey results reported here, along with questions posed to us by individual patients, indicate that the immediate concerns of many patients undergoing diagnostic imaging procedures are related to risks other than cancer,” the authors wrote. “Thus, we first need to focus educational efforts on teaching patients that tissue effects and heritable mutations are not risks of exposure to diagnostic radiation doses.”

Steele and colleagues said their study did have limitations. For instance, data came from patients who all received care from the same cancer center instead of a variety of locations. The authors added that the low response rate could be viewed as a limitation by some, but it was actually “typical of response rates for computer-based external surveys.”