It is recommended that CT scans are performed exclusively in the presence of clinical features suggesting CT-detectable lung changes.It is also crucial that pediatricians or pneumologists determine the clinical indications to CT, so that the radiologists use the most appropriate protocols with the lowest radiation exposure (ALARA principle – As low as reasonably Possible). The chest CT scan is a fundamental diagnostic test for many respiratory diseases, as it allows to visualize in detail all the thoracic structures and the pulmonary parenchyma. Unfortunately, the CT is burdened by the inevitable exposure to ionizing radiation (corresponding, for a traditional chest CT scan, to about 150 chest radiographs), which, in pediatric age, constitutes a significant biological risk increasing the incidence of many neoplasms. Should CT be necessary, it is recommended to adopt pediatric CT protocols in order to obtain good images with minimal radiation exposure.