A systematic review of radiation dose to the eye lens from pediatric brain computed tomography scans

With the increasing use of pediatric brain computed tomography (CT) and the International Commission on Radiological Protection's revised threshold for radiation-induced lens opacities, concerns have grown regarding cumulative radiation exposure to the eye lens.

This review examines the magnitude of lens doses reported in pediatric brain CT and the methodologies used to estimate these doses.

A systematic literature search of MedLine, Embase, and PubMed (2012-2024) identified 18 eligible studies, including direct patient measurements, phantom-based experiments, and computational modeling.

Reported lens doses varied widely across studies. Software-based tools generally estimate higher doses than those measured directly on patients or phantoms. Multiple dose-reduction strategies such as gantry tilting, organ-based tube current modulation, and protocol optimization were effective in significantly lowering lens exposure without compromising diagnostic quality.

In all cases, individual scan doses remain below the cataractogenic threshold. However, children undergoing repeated imaging may exceed this limit over time. Cumulative lens dose tracking and routine implementation of orbit-sparing techniques are recommended to reduce long-term radiation risk in vulnerable pediatric populations.