Radiation doses to emergency department patients undergoing computed tomography.

Objectives: Computed tomography (CT) use is increasing in the emergency department (ED). Many physicians are concerned about exposing patients to radiation from CT scanning, but estimates of radiation doses vary. This study's objective was to determine the radiation doses from CT scanning for common indications in a Canadian ED using modern multidetector CT scanners.

Methods: We conducted a health records review of consecutive adult patients seen at two busy tertiary care EDs over a 2-month period who underwent CT scanning ordered by emergency physicians. Cases were identified by searching an imaging database. Data collected included patient age and sex, study indication, scanner model, body area, and reported dose-length product. Effective dose per scan was calculated from reported dose-length product. Data were collected on a standardized form, entered into an electronic database, and analyzed with descriptive statistics and 95% CIs.

Results: During the study period, emergency physicians assessed 19,880 patients. Overall, 2,720 (13.7%) underwent CT scanning, and of these, 144 (5.3%) patients had more than one scan. Patients had a mean age of 59.0 years, and 45.3% were men. Mean doses for the most common indications were as follows: simple head, 2.9 mSv; cervical spine, 5.7 mSv; complex head, 9.3 mSv; CT pulmonary angiogram, 11.2 mSv; abdomen (nontraumatic abdominal pain), 15.4 mSv; and abdomen (renal colic), 9.8 mSv.

Conclusions: Approximately one in seven ED patients had a CT scan. Emergency physicians should be aware of typical radiation doses for the studies they order and how the dose varies by protocol and indication.