Comparative Analysis of Corneal and Lens Doses in Nuclear Medicine and Impact of Lead Eyeglasses: A Monte Carlo Simulation Approach

Research on eye lens dosimetry for radiation workers has increased after the 2012 International Commission on Radiological Protection 118 update on eye lens dose limits, while corneal dosimetry has remained underexplored due to historical focus and measurement challenges. This study employed a high-resolution digital eye phantom in Monte Carlo simulations to estimate corneal and lens doses for nuclear medicine staff, with and without lead glasses. Using the Monte Carlo code GATE (Geant4 Application for Tomographic Emission) (version 9.0), based on the GEANT4 toolkit (version 10.6), we estimated doses from primary and scattered radiation emitted by common radionuclides (18F, 131I, 99mTc) under varying lead glass shielding thicknesses (0–0.75 mm). The simulations demonstrated that across all radionuclides, the dose to the cornea was consistently higher than the dose to the lens. Moreover, the ratio of corneal to lens dose increased with thicker lead glasses, reflecting a greater relative dose reduction to the lens. These findings indicate that while thicker lead glasses enhance lens protection, they reduce corneal exposure less effectively, thereby raising the cornea-to-lens dose ratio. Although protective eyewear remains important, its practicality may be limited by diminishing returns in shielding effectiveness and potential discomfort. Overall, this work highlights the necessity of considering both corneal and lens dosimetry to optimize occupational eye protection strategies in nuclear medicine. Received: 29 March 2025 | Revised: 8 September 2025 | Accepted: 17 December 2025 Conflicts of Interest The authors declare that they have no conflicts of interest to this work. Data Availability Statement Data sharing is not applicable to this article as no new data were created or analyzed in this study. Author Contribution Statement Zahra Akbari Khanaposhtani: Conceptualization, Methodology, Software, Formal analysis, Investigation, Data curation, Writing – original draft, Visualization. Hossein Rajabi: Conceptualization, Methodology, Validation, Resources, Writing – review & editing, Supervision, Project administration.