Establishing weight-based diagnostic reference levels for neonatal chest X-rays

Abstract

Introduction: As weights among neonates can vary from <900 g to >2.5 kg, weight-based Diagnostic Reference Levels (DRLs) specific to the neonatal intensive care unit (NICU) are essential. Repeated radiation exposure to this sensitive patient group raises concerns regarding high cumulative radiation doses and the potential for long-term health detriment. This study aimed to establish weight-based DRLs for neonates undergoing mobile chest radiography (CXR) in the NICU.

Methods: Neonates were classified into three discrete groups; <1000, 1000-2500 and >2500 g. Data were collected prospectively over three months; 95 DAP values were collected, and five were excluded due to poor technique, leaving 90 patients that met the inclusion criteria for mobile CXR in the NICU. Dose-area-product (DAP) in mGycm², the peak kilovoltage (kVp) and the product of tube current and exposure time (mAs) were retrieved from the Picture Archiving and Communication System (PACS). Images and radiological reports were also analysed to confirm diagnostic image quality (IQ). Local DRLs (LDRLs) were derived using the median DAP, and national DRLs were suggested using the 3rd quartile value.

Results: The proposed LDRLs for neonates weighing <1000 g was 2.7 mGycm², for neonates weighing between 1000 g and 2500 g, it was 3.7 mGycm², and for neonates weighing >2500 g it was 6.6 mGycm². The radiation dose received by the 90 (100%) neonates included in the study fell below 11.4 mGycm²; of these, 82% of the DAP values fell below the study institution's existing LDRL of 7.25 mGycm².

Conclusion: Weight-based DRLs provide crucial information on doses to this specific radiation-sensitive group. This work recommends using weight-based categories for DRLs and serves as a benchmark for neonatal CXR standardisation and optimisation.

Implications for practice: The proposed weight-based DRLs can be adopted for neonates' locally, nationally and internationally.

Keywords: Diagnostic reference level; Neonatal chest X-ray; Radiation dose.