Explaining radiation dose exposure : The role of the banana equivalent dose compared to the effective dose in patient communication

Abstract

Communicating the amount and effects of ionizing radiation to patients prior to an examination using x‑rays is associated with challenges: first, calculating the expected dose prior to the examination and, second, quantifying and illustrating cancer risks. Analogies, such as comparing radiation exposure to accident risks, have limitations and may evoke unease. This study explores and compares two new approaches to discuss radiation exposure from common clinical examinations with patients: effective dose and exposure based on radioactive potassium-40 intake from the ingestion of bananas, the banana equivalent dose (BED). The effective doses of the diagnostic reference levels (DRL) for computed tomography (CT) andX-ray examinations in adults were calculated using mean conversion factors for specific anatomic body regions. For the BED calculation of the diagnostic reference levels, the radiation dose from aconventional banana ingested over 50years per becquerel was calculated. The outcomes were juxtaposed against an equivalent number of bananas and its respective radiation doses. The calculated doses, namely effective dose and BED, of the German DRL can serve as areliable metric to discuss radiation exposure from medical imaging with patients prior to an examination. This is the first study to calculate the effective doses of the current DRL and to compare these with the pseudoscientific unit BED. While the BED serves as an interesting illustration to metaphorize radiation exposure, it is recommended to use the calculated effective dose of the DRL as the basis for educational consultations with patients.