Radiation doses and risks to neonates undergoing radiographic examinations in intensive care units in Tunisia

Abstract

Purpose: To assess the radiation doses to neonates from diagnostic radiography in order to derive the local diagnostic reference levels (LDRLs) for optimisation purposes.

Methods: This study was carried out in the neonatal intensive care units (NICU) of  two hospitals in Tunis. 134 babies, with weights ranging from 635 g to 6680 g, performed chest-abdomen X-ray examinations. Neonates were categorized into groups of birth weight. For each X-ray examination, patient data and exposure parameters were recorded. Dose area product (DAP) was measured and entrance surface dose (ESD) was estimated. Effective dose was calculated from the Monte Carlo simulation software PCXMC.

Results: DAP values increased with neonatal weight and demonstrated a wide variation (5.0 - 43.0 mGy.cm², mean 23.4 mGy.cm²) for patient weight from 600 g to 4000 g. A wide variation was also observed for ESD (14 - 93 μGy, mean 55.2 μGy). The LDRLs expressed in term of DAP were estimated to be 17.6 mGy.cm² and 29.1 mGy.cm² for the first and the second NICU, respectively. In terms of effective dose, the average value was about 31.6 μSv per single radiological examination. The results show the necessity to use a standardized protocol with high voltage technique combined to lower current time product (mAs) values and an adapted collimation which could lead to further reductions in the neonatal doses.

Conclusion: This study presents the LDRLs and the effective doses for neonates in two NICUs and demonstrates the necessity to optimize patient protection for this category of patient.