Neonatal chest and abdominal radiation dosimetry: a comparison of two radiographic techniques

Radiographs of the chest and the abdomen are the most commonly requested diagnostic X-ray examinations undertaken in neonatal intensive care units. Frequently, for a single child, both radiographs are requested simultaneously. These images can be obtained either as two separate exposures (one of the chest and one of the abdomen), or as a Single exposure to include both anatomical regions on one film. This study compared the effective dose imparted as a result of each technique. A neonatal anthropomorphic phantom was designed and constructed, and each radiographic technique was simulated. Entrance surface dose (ESD) and dose-area product (DAP) were measured and estimates of effective dose were made from the DAP values. The mean effective dose for the separate exposure technique was estimated to be 37.3 mu Sv compared with 35.5 mu Sv for the combined exposure technique. However, observed variations in field size gave rise to uncertainties in DAP and thus the effective doses estimated from it. Hence, no significant difference in effective dose was observed between the radiographic techniques. The observed coefficient of variation in field size (16% for a 2.5 kg neonate) demonstrates that good standards of radiographic practice are more important than choice of technique.