Single- and multi-slice computed tomography (CT) is regarded as the primary imaging tool in traumatology, both in adults and children. For complicated infectious disease and renal tumours, these techniques are recommended only as secondary diagnostic tools. Specifically, multi-slice CT (MSCT) provides excellent spatial resolution, which is a particular advantage for the evaluation of small structures as they are typical in children. However, MSCT offers more information than is required for diagnosis. Therefore, low-dose protocols are necessary for paediatric examinations. The CT dose-index (CTDI(vol)) should not exceed 2 mGy for newborns, 4 mGy for toddlers, 5 mGy for elementary school children, and 8 mGy for adolescents.