Cumulative effective doses delivered by radiographs to preterm infants in a neonatal intensive care unit

OBJECTIVE. We sought to determine the number and distribution of radiographs and the cumulative effective radiograph doses (cED) received by a population of preterm infants (PIs) hospitalized in an NICU. STUDY DESIGN. We reviewed the files of all preterm infants (gestational age: < 34 weeks) who were admitted to an NICU during an 18-month period and were discharged alive. A generalized additive model was used to study the relationship between cED and patient characteristics. RESULTS. Four hundred fifty files were analyzed. The median gestational age was 30.1 weeks (range: 24.1-33.9 weeks), and the median birth weight was 1250 g (range: 520-2760 g). The median number of radiographs per infant was 10.6 (range: 0-95), and the median cED was 138 mu Sv (range: 0-1450 mu Sv). The cumulative dose exceeded 500 mu Sv in 7.6% of the cases. Factors that influenced the cumulative effective dose were gestational age, birth weight, care procedures, and clinical adverse events. CONCLUSIONS. Given the potentially life-threatening complications of PIs, cumulative radiograph doses received in the ICU seem low with regard to environmental exposure and international recommendations. Additional studies are needed to evaluate the possible lifetime consequences of exposure to ionizing radiation at this age.