Topogram-based tube current modulation of head computed tomography for optimizing image quality while protecting the eye lens with shielding:

BackgroundMultiple rounds of head computed tomography (CT) scans increase the risk of radiation-induced lens opacification.PurposeTo investigate the effects of CT eye shielding and topogram-based tube current modulation (TCM) on the radiation dose received by the lens and the image quality of nasal and periorbital imaging.Material and MethodsAn anthropomorphic phantom was CT-scanned using either automatic tube current modulation or a fixed tube current. The lens radiation dose was estimated using cropped Gafchromic films irradiated with or without a shield over the orbit. Image quality, assessed using regions of interest drawn on the bilateral extraorbital areas and the nasal bone with a water-based marker, was evaluated using both a signal-to-noise ratio (SNR) and contrast-noise ratio (CNR). Two CT specialists independently assessed image artifacts using a three-point Likert scale.ResultsThe estimated radiation dose received by the lens was significantly lower when barium sulfate or bismuth-antimony shie...