Impact of added filtration and field size on operator eye lens exposure in over-table fluoroscopy: a Monte Carlo...

This study characterized operator eye lens exposure in over-table fluoroscopy using Monte Carlo simulation, focusing on beam quality and geometry under simulated conditions. Absorbed doses were calculated using voxel phantoms across tube voltages (75-95 kV), filtrations (Al 2.5-4.5 mm, Cu 0.0-0.5 mm), and field sizes (10-30 cm). Grid correction was applied to normalize results to detector entrance dose. Beam hardening via increased filtration significantly reduced lens doses, although the rate of dose reduction gradually diminished as Cu thickness increased. Field size reduction was the most effective strategy; a 10 cm field reduced the dose by 40-50% compared to a 30 cm field. When using Patient Entrance Reference Point (PERP) values to estimate operator lens exposure, beam quality must be considered, as the same PERP value can yield substantially different operator doses depending on filtration. Field size restriction remains the most effective measure for dose reduction.