Radiation exposure from diagnostic imaging in the pediatric intensive care unit

To determine the range of radiation exposure from diagnostic imaging in children requiring mechanical ventilation.

Prospective, observational.

Tertiary pediatric critical care unit.

We enrolled pediatric critical care unit patients requiring mechanical ventilation.

None.

Thoracic radiation exposure while the patient was in the pediatric critical care unit was measured using a small, radiolucent dosimeter secured to the anterior chest wall. Demographic data, diagnoses, and number and type of radiographic procedures were recorded. Differences between exposures by admission diagnoses were analyzed by rank sum test. Relationships between exposure and risk factors were assessed using multiple linear regression and Pearson correlation. Sixty-nine subjects were enrolled over a 175-day period. Subjects experienced a mean (± SD) of 11 ± 11 days of mechanical ventilation during which they underwent a mean of 14 ± 16 chest radiographs and 5 ± 4 other plain films. Subjects who had only plain radiographic studies (CXR group) had a median thoracic exposure of 1.02 (range, 0.13-28.26) mGy and a median daily exposure of 0.16 (range, 0.02-1.99) mGy/day. Subjects who had computed tomography and/or fluoroscopy studies in addition to plain radiographs (CXR+ group) had a median total thoracic exposure of 3.71 (range, 0.77-33.41) mGy and median daily exposure of 0.37 (range, 0.04-3.71) mGy/day, both of which were significantly higher than for subjects in the CXR group. There was no significant difference in average daily exposures according to admission diagnoses and daily exposure could not be predicted from a combination of variables, including age, body mass index, gender, or length of stay. Total number of radiologic studies was correlated, as expected, with duration of ventilation (r = 0.941, p < .0001). Exposure was significantly higher in patients who underwent computed tomography scans or fluoroscopy studies than in patients who only had plain radiography.

Ventilated pediatric intensive care unit patients experienced an average daily thoracic radiation exposure above background environmental exposure and exposure varied widely, but exposures would not be expected to cause acute or chronic toxicity. Overall patient exposures were less than that received from 1 yr of natural background radiation.