Diagnostic quality of neonatal radiograph images after 50% radiation-dose reduction on a computed radiography system

Abstract

Background X-rays are frequently performed in the neonatal intensive care unit (NICU) setting, leading to a high radiation burden on patients. Neonates are more radiosensitive than adults, therefore all imaging should be done with the smallest possible dose. The European Commission guidelines suggest a 60-65 kV setting and maximum entrance skin kerma dose of 80 μGy, but no guidance is provided regarding the tube current (mAs) setting. Consequently, there is large variation in the mAs at different institutions. Objective To determine whether image quality would be compromised by utilising exposure parameter settings of 55 kV and 1,6 mAs, which delivers a radiation exposure of approximately 24 μGy using a computed radiography system in the NICU. This mAs setting can be used as a guideline, thereby preventing unnecessary radiation exposure. This will result in a significantly lower entrance skin kerma than the suggested European Committee guideline. Materials and methods A prospective study was performed and 60 NICU chest X-ray image sets were collected. These contained standard-dose images of 3,2mAs and lower dose images of 1,6mAs, acquired on the same day on a computed radiography system. The kV remained unchanged at 55kV. Randomised image sets were evaluated by five consultants regarding general image quality and some specific aspects thereof. Results. Generally, the routine-dose images had a better appearance. However, the image quality was considered acceptable for all the lower-dose exposures. Conclusion Computed radiography systems allow the use of lower radiation exposure without loss of diagnostic image detail. The radiation-dose burden could be significantly reduced in the NICU by using lower-dose settings. NICU institutions should consider to using 1,6 mAs and 55 kV as reference guidelines for the maximum setting for CR-system for all babies in NICU. This study suggests that the current EC radiation dose guideline of 80 μGy for neonates can be reduced by 66% without meaningful loss of diagnostic image quality.