Dose and image quality optimization in neonatal radiography

In a special care baby unit, neonates, mainly premature, encounter serious to life-threatening diseases, the timely diagnosis and treatment of which may require a large number of radiographs. Increased neonatal radiosensitivity and longer life expectancy increase the risk of radiation-induced cancer, which emphasizes the importance of minimizing dose while maintaining clinically satisfactory image quality. An optimization study on radiation dose and image quality in neonatal radiography is presented. Neonates were categorized into four groups depending on birthweight. For a total of 378 chest and chest-abdomen radiographs, exposure parameters were recorded. Entrance surface dose (ESD) was estimated and dose-area product (DAP) was measured. Image quality evaluation was performed by two observers and was based on the visibility of certain anatomical features and catheters placed during treatment using a five-grade scale. ESD values increased with neonatal weight and demonstrated wide variation (16.4-76.9 mu Gy, mean 38.2 mu Gy). A wide variation was also observed in DAP values (1.2-15.0 mGycm(2), mean 7.2 mGycm(2)). Image quality evaluation revealed the feasibility of achieving a diagnostically satisfactory image (score > 70%) using both low and high tube voltage techniques, with the latter resulting in reduced ESDs. The majority of estimated ESDs are in accordance with the reference level of 50 mu Gy recommended by the National Radiological Protection Board for neonatal radiography. The results suggest that the use of high tube voltage techniques could result in further reductions in neonatal dose, without image quality degradation, underlying the requirement for establishing standard examination protocols for neonatal radiography with respect to neonatal weight.