Comparison of effective dose and image quality for newborn imaging on seven commonly used CT scanners

This study compares the image quality and the patient doses on seven different computed tomography (CT) scanners for newborn chest imaging. The dose was measured by using an anthropomorphic newborn phantom and thermoluminescence dosemeters (TLDs). The effective dose was estimated separately based on a dose-length-product display, TLD measurements and the ImPACT CT dose calculation software. The image quality was assessed using a signal-to-noise ratio and a contrast-to-noise ratio (CNR). In order to compare the different scanners, a figure of merit (FOM) based on the rate of CNR² and computed tomography dose index (CTDI_vol) was calculated. The organ doses within the scan area ranged between 0.3 and 2.9 mGy and they depended on the organ and used scanner. The highest effective dose (1.1 mSv) was observed on Aquilion 32 and the lowest effective dose was observed on the Aquilion One (0.22 mSv). The lowest organ doses and highest FOM were observed on the Optima 660. With the Aquilion One and the Definition Dual Flash the examination was 71-90% faster when compared with other scanners. Newer devices equipped with novel dose-saving methods provide a lower dose, as well as take better advantage of the radiation in the image formation. (authors)