Hospitalized patients have been estimated to receive a mean dose of 14.8 milliSieverts (mSv), a majority of which can be attributed to CT examinations, according to a study published in the February issue of the Journal of the American College of Radiology.

Though the chances may be small, the potential for future cancer risk from radiation exposure due to CT exams has been recently highlighted in publications. The study’s lead author, Arielle C. Lutterman, MD, of the Emory University School of Medicine in Atlanta, and colleagues performed a retrospective study of diagnostic imaging use in patients during a single hospitalization. The researchers aimed to estimate cumulative radiation exposure, determine radiation exposure based on imaging modality, and evaluate estimated doses in relation to age, sex, and diagnoses.

Two hundred consecutive patients underwent 2,751 diagnostic imaging studies at two hospitals during the study. The electronic record of each patient was reviewed after a single hospitalization. Lutterman et al calculated dose estimates for each CT, fluoroscopy, nuclear medicine, plain film, and interventional radiology study or procedure.

Of the total imaging studies performed, 9.7 percent were CT, 6.1 percent were ultrasound, 2.5 percent were interventional radiology, 2.2 percent were MRI, and 0.4 percent were nuclear medicine. The mean dose estimate per patient was 14.8 mSv, with a total range of 0 mSv to 130.5 mSv. Mean dose estimates were significantly higher for patients that spent part of their hospitalizations in the ICU. CT examinations were attributed to 82.1 percent of the total radiation dose estimate. Eleven patients received radiation dose estimates greater than or equal to 50 mSv. Two patients received radiation dose estimates greater than or equal to 100 mSv.

“Radiologists should be vigilant in monitoring CT imaging protocols so that when a CT is ordered, the resultant radiation exposure will be as low as is reasonably achievable. Consideration should be given to alternative forms of imaging such as ultrasound and MRI when possible and based on a given institution's resources, access and expertise,” concluded Lutterman and colleagues.