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

Radiographs of the chest and the abdomen are the most commonly requested di agnostic X-ray examinations undertaken in neonatal intensive care units. Fr equently, 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 ana tomical regions on one film. This study compared the effective dose imparte d as a result of each technique. A neonatal anthropomorphic phantom was des igned and constructed, and each radiographic technique was simulated. Entra nce surface dose (ESD) and dose-area product (DAP) were measured and estima tes of effective dose were made from tile DAP values. The mean effective do se for the separate exposure technique was estimated to be 37.3 mu Sv compa red 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 eff ective doses estimated from it. Hence, no significant difference in effecti ve dose was observed between the radiographic techniques. Tile observed coe fficient of variation in field size (16% for a 2.5 kg neonate) demonstrates that good standards of radiographic practice are more important than choic e of technique.