Comparative analysis of corneal and lens doses in nuclear medicine and impact of lead eyeglasses: a Monte Carlo simulation approach

TL;DR

This study uses Monte Carlo simulations with a digital eye phantom to compare corneal and lens radiation doses in nuclear medicine, highlighting the impact of lead glasses on dose reduction and protection efficiency.

Contribution

It provides the first detailed comparison of corneal and lens doses using high-resolution simulations, emphasizing the differential effects of lead glasses on eye protection in nuclear medicine.

Findings

Corneal doses exceed lens doses across radionuclides.

Thicker lead glasses reduce lens doses more effectively than corneal doses.

Increasing lead thickness raises the corneal-to-lens dose ratio.

Abstract

Objective: Research on eye lens dosimetry for radiation workers has increased after the 2012 ICRP118 update on eye lens dose limits. However, corneal dosimetry remains underexplored due to historical focus and measurement challenges. This study uses 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. Method: The Monte Carlo code GATE (version 9.0) based on GEANT4 (version 10.6) was used to estimate and compare doses in a digital eye phantom, accounting for primary and scattered radiation from common radionuclides (F18, I131, Tc99m) with varying lead glass shielding (0 to 0.75 mm). Results: Across all radionuclides, the dose to the cornea was consistently higher than the dose to the lens. Notably, the ratio of corneal to lens dose increased with thicker lead glasses, indicating a greater dose reduction to the lens compared to the cornea. Conclusion: The findings show that corneal doses from all studied radionuclides exceeded lens doses. Although increasing lead glass thickness reduced both, the reduction was more significant for the lens, raising the cornea-to-lens dose ratio. This trend suggests that while thicker lead glasses enhance lens protection, their practicality may be limited due to diminishing returns and potential discomfort. Keywords: Corneal Dosimetry, Lens Dosimetry, Monte Carlo, GATE, Nuclear Medicine, Simulation