Patients Often in the Dark on Radiation Risks From Medical Imaging

Patients who underwent medical imaging procedures had limited knowledge about medical radiation overall, including the risks, according to a survey by Italian researchers.

For example, 55.1% of those responding to the survey didn’t know that chest CT exams deliver larger doses of radiation than chest x-rays, while only 52.3% knew that radiation can be emitted after nuclear medicine examinations, reported Lorenzo Faggioni, MD, PhD, of the University of Pisa, and colleagues.

In addition, only 31.7% of respondents correctly answered a question about the association between CT dose and patient body weight, while 23.3% believed that radiation risk was unrelated to age.

“These results suggest the need for new strategies even with the presence of many public radiation protection and awareness campaigns for more than a decade,” the researchers wrote in JAMA Network Open.

“It is time to inform patients of medical imaging risks,” said Carly Stewart, MHA, and Rebecca Smith-Bindman, MD, both of the University of California San Francisco, writing in an accompanying commentary, explaining that when patients misunderstand the potential harms of imaging “they cannot appropriately balance the risks and benefits and engage knowledgeably in their care.”

The commentators called for “a systemic and seismic shift in educating physicians and patients, in having candid conversations with patients around imaging that acknowledge the tradeoffs, and in justifying the use of all medical radiation exposure.”

“In doing so, we improve the safety of medical imaging while reducing the physical, social, and economic toll of overuse and disease,” Stewart and Smith-Bindman said. “A patient-centered care approach would oblige health care clinicians, at a minimum, to disclose information on the risks, benefits, and alternatives to radiation-based imaging.”

For the survey, patients age 18 and older who were waiting for medical imaging in waiting rooms in 16 Italian teaching and nonteaching hospitals were asked about their basic knowledge of ionizing radiation levels and health risks, as well as information and communication about radiation protection issues. Of the 3,039 patients invited to participate, 94.3% responded.

Of the 2,866 patients who participated, 53.4% were women. The patient sample was fairly well balanced geographically, with education levels that ranged from low in 23.1% of respondents to intermediate in 47.7% and high in 29%. The vast majority of patients (98.5%) reported having undergone at least one previous radiological test.

Other key findings:

• CT scans and mammography, respectively, were correctly categorized as radiation-based imaging by 71% and 38.4% of patients

• Ultrasonography and MRI were correctly identified as a radiation-free imaging by 85% and 43.0%

Regarding sources of information on medical radiation, only 42.7% of respondents said they had been informed about radiation risks during an imaging examination, even though 80.4% expressed a preference to receive such information from healthcare professionals; most (68%) said they would like to receive this information from radiologists, followed by general practitioners (56.3%) and radiographers (52.5%).

Stewart and Smith-Bindman pointed out that while radiologists have greater knowledge of the biological effects of radiation, radiologists have only minimal interaction with patients. In addition, the commentators noted, a 2017 survey of physicians from obstetrics, gynecology, family practice, emergency, and internal medicine found they all had a relatively low baseline knowledge of ionizing radiation across all specialties and at all levels of training,

“It is the responsibility of clinicians who order tests to help patients make informed decisions about their health care,” Stewart and Smith-Bindman wrote. “It is the responsibility of health leaders and systems to ensure ordering clinicians are equipped with the knowledge to do so.”

Faggioni and colleagues found on univariable analysis that a better knowledge of radiation issues was associated with receiving information from healthcare professionals (OR 1.71, 95% CI 1.43-2.03) and having a higher educational level (intermediate vs low: OR 1.48, 95% CI 1.17-1.88; high vs low: OR 2.68, 95% CI,2.09-3.43).

Study limitations, the researchers said, included potential selection bias because there was no differentiation in imaging modality when patients were recruited, as well as a sample selection that was not representative of the general population.