Patient Knowledge and Perception of Radiation Risk in Diagnostic Imaging: A Cross-Sectional Study

BACKGROUND: Informed consent dictates that patients appreciate the risks and benefits of imaging techniques that use ionizing radiation. Computed tomography (CT) and X-ray carry a stochastic lifetime risk of inducing malignancy. This risk is difficult to convey and often overlooked. OBJECTIVE: This work aims to establish some basics regarding patient knowledge and perception of medical imaging to facilitate an informed consent process. METHOD: A questionnaire survey was conducted in a general orthopedic outpatient clinic in a United Kingdom tertiary center. RESULTS: There were 219 respondents. Twenty-two percent understood that CT produces ionizing radiation associated with cancer risk, but only 6% knew about cancer risk from natural background radiation. Only 25% knew that CT has a higher cancer risk than X-ray. The majority (93%) knew that smoking poses higher risk than X-rays. The Internet as an information source was statistically associated with concern about X-rays. CONCLUSIONS: Patients underestimated CT cancer risk and were unable to compare risk between imaging modalities. Risk can be more effectively conveyed using better known relatable risks as comparators. Patient groups associated with lower knowledge, most in need of education, were highlighted.