Low-dose ionising radiation from medical imaging in patients hospitalised in internal medicine

Background: Medical imaging is responsible for increasing exposure to low-dose ionising radiation in the general population. The extent of exposure in specific patient populations remains to be determined. Aim: We sought to determine the level of exposure in patients hospitalised in General Internal Medicine. Methods: In this retrospective cohort study, we searched the Centre Informatise de Recherche Evaluative en Services et Soins de Sante database for adult patients hospitalised in General Internal Medicine from 1 January 2008 to 31 December 2008. We collected data on demographics, co-morbidities, and radiological and nuclear imaging. We used data from the literature to calculate an estimated annual effective dose for each patient and searched for factors associated with higher exposure. Results: One thousand one hundred eighty-seven (1187) patients were hospitalised at least once during the study period. The median age was 69 years (interquartile range 5681) and 636 (53.6%) were men. The median annual effective dose of the whole cohort was 8.7 mSv/year. Patients aged between 55 and 80 years were exposed to a higher median effective dose compared with their younger and older counterparts (P < 0.001). Patients with cardiac, pulmonary, peripheral arterial and neoplastic disease were at higher risk of exposure to high and very high annual effective dose (P < 0.01). Patients with longer hospitalisations were at higher risk of exposure to high and very high annual effective dose (P < 0.01). Conclusion: Patients hospitalised on a General Internal Medicine ward are exposed to three times more ionising radiation than the general population.