Cumulative radiation dose caused by radiologic studies in critically ill trauma patients.

BACKGROUND Critically ill trauma patients undergo many radiologic studies, but the cumulative radiation dose is unknown. The purpose of this study was to estimate the cumulative effective dose (CED) of radiation resulting from radiologic studies in critically ill trauma patients. METHODS The study group was composed of trauma patients at an urban Level I trauma center with surgical intensive care unit length of stay (LOS) greater than 30 days. The radiology records were reviewed. A typical effective dose per study for each type of plain film radiograph, computed tomographic scan, fluoroscopic study, and nuclear medicine study was used to calculate CED. RESULTS Forty-six patients met criteria. The mean surgical intensive care unit and hospital LOS were 42.7 +/- 14.0 and 59.5 +/- 28.5 days, respectively. The mean Injury Severity Score was 32.2 +/- 15.0. The mean number of studies per patient was 70.1 +/- 29.0 plain film radiographs, 7.8 +/- 4.1 computed tomographic scans, 2.5 +/- 2.6 fluoroscopic studies, and 0.065 +/- 0.33 nuclear medicine study. The mean CED was 106 +/- 59 mSv per patient (range, 11-289 mSv; median, 104 mSv). Among age, mechanism, Injury Severity Score, and LOS, there was no statistically significant predictor of high CED. The mean CED in the study group was 30 times higher than the average yearly radiation dose from all sources for individuals in the United States. The theoretical additional morbidity attributable to radiologic studies was 0.78%. CONCLUSION From a radiobiologic perspective, risk-to-benefit ratios of radiologic studies are favorable, given the importance of medical information obtained. Current practice patterns regarding use of radiologic studies appear to be acceptable.