Minimising radiation dose to the lens in axial computed tomography of the temporal

In this study, 25 randomly selected CT scans of temporal bones performed in a busy radiology department were retrospectively analysed with particular attention paid to the number of sections passing through the orbits. Thirteen examinations were found to include sections through the eyes, thereby resulting in unnecessary radiation to the lens. The importance of proper scanning technique is therefore emphasised. The mean radiation dose to the eyes in axial CT examination of the temporal bones was determined by the use of thermoluminescent dosimeters taped to the eyelids. The authors concluded that appropriate scanning techniques can reduce the radiation dose to the orbit whilst imaging the temporal bone. All the relevant information can usually be obtained without any of the sections passing through the lens. The radiation dose to the lens was increased when additional sections were performed to obtain information about the jugular fossa.