After a deep analysis of all collected data and a critical review of the images in the light of their IQ scores, we could identify the most frequent problems, namely: high noise, wrong protocol choice, wrong selection of the scanning length, malfunctioning of the AEC due to centering errors and wrong positioning of patient gonads shielding (Fig. 6). One of the main problems regarding protocol choice was that the dedicated “Chest osteo low dose – children” protocol was frequently used without changing parameters according to patient age/dimension, so images were acceptable only for the smallest ones.

To optimize acquisition parameters and obtain adequate IQ, several low-dose chest CT scan protocols have been defined dividing patients by weight classes, as suggested for paediatric patients [4]. Since the anthropometric differences in paediatric patients of the same age can be relevant, especially when they are sick, the choice of weight as a parameter to identify the acquisition protocol should give rise to far less differences in the final images. In the case of follow-up, the choice of the same acquisition protocol allows the radiologist to better evaluate the possible progression of the disease comparing images with the same IQ over time.

In order to update CT staff on the correct use of the different dose reduction and optimization strategies, a refresh course was organized for all radiographers working with paediatric patients.

Acknowledgement: This work was supported, in part, by grant from the project “Procedure radiologiche: informazione della dose al paziente” Compagnia San Paolo, Torino.