Diagnostic ionizing radiation exposure in premature patients

Concern regarding the magnitude and consequences of diagnostic radiation exposure in premature infants in neonatal intensive care units (NICUs) has increased as survival of premature infants has improved. Radiation exposure is not often rigorously monitored in NICU patients. The purpose of this observational study was to quantify the amount of ionizing radiation exposure in infants <33 weeks gestational age and to identify the indications for diagnostic imaging.

We conducted a retrospective review of 215 premature infants who were <33 weeks gestation and who received central venous line (CVL) placement during their NICU stay during the period from 2006 to 2011. Absorbed ionizing radiation was estimated using the method of Puch-Kapst and colleagues (2009) and compared with recommended radiation exposure limits. All infants were 29.2±2.3 weeks (mean±s.d.) and 1262±433 g birth weight.

Subjects received 15±15 radiographs (4.4±2.9 for CVL placement, 5.7±9.8 for gastrointestinal (GI) evaluations and 5.2±9.3 for respiratory indications). Eleven infants (5.1%) received more than the maximum recommended radiation from radiographs (>1000 μSv). Inclusion of fluoroscopic procedures increased to 26 the number of infants (12.1%) who received more than the maximum recommended 1000 μSv.

Ionizing radiation exposure that exceeded the recommended maximum in premature infants at high risk for long-term sequelae occurred in 12.1% of infants who were <33 weeks gestation and who were cared for in our NICU over the past 5 years. CVL placement accounted for 22% of this radiation exposure. GI evaluations accounted for the greatest amount of ionizing radiation exposure. We suggest that the increased use of other imaging strategies may reduce total ionizing radiation exposure in this vulnerable population.