Abstract and Introduction
Objective: 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.
Study Design: 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.
Result: 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.
Conclusion: 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.
Ionizing radiation exposure has become an increasingly important public health concern as the rates of cancer increase in the general population. During pregnancy, diagnostic X-ray exposure to the maternal-fetal unit should be avoided unless absolutely necessary to avoid potential harmful effects to the developing fetus where high mitotic activity and small size make the fetus particularly vulnerable. Nonetheless, although there is concern, the actual long-term effects of early radiation exposure to the fetus and the premature neonate are not known. While neonatal intensive care unit (NICU) care has improved over the past two decades, an increasing number of premature survivors have developed respiratory, gastrointestinal (GI) and neurodevelopmental morbidities that have required multiple diagnostic imaging examinations. Monitoring the amount of ionizing radiation exposure during any given infant's NICU stay has not been routinely quantified, and it is unclear what level of radiation exposure is safe for premature infants. Increased cancer risk has been demonstrated among pediatric patients exposed to computed tomography (CT) vs those not exposed to CT. A dose-dependent increase in the risk of leukemia and brain tumors in children exposed to CT scans during childhood has been reported and the Food and Drug Administration has launched an initiative to reduce radiation exposure in children. Additional efforts are also underway as part of the 'Image Gently' campaign.
The purpose of this study was to quantify the level of radiation exposure in infants at greatest risk, that is, those premature infants who are <33 weeks gestation and who are deemed sufficiently ill to justify placement of a central venous line (CVL). The indications and types of radiologic examinations are quantified to allow use of this data to design strategies intended to decrease the amount of radiation exposure in this vulnerable population. The average effective radiation dose for each type of radiographic exam in our NICU patients was taken from Puch-Kapst and colleagues. For CT examinations, the effective doses calculated by Huda and Vance were used. The effective doses used from both references were representative of neonates of average size and weight using typical radiographic and CT image acquisition technique factors.
J Perinatol. 2014;34(5):392-395. © 2014 Nature Publishing Group