A study of the underestimation of eye lens dose with current eye dosemeters for interventional clinicians wearing lead glasses

Abstract

The reduction in the occupational dose limit of the eye lens has created the need for optimising eye protection and dose assessment, in particular for interventional clinicians. Lead glasses are one of the protection tools for shielding the eyes, but assessing the eye lens dose when these are in place remains challenging. In this study, we evaluated the impact of the position of Hp(3) dosemeters on the estimated eye lens dose when lead glasses are used in interventional settings. Using the Monte Carlo method (MCNPX), an interventional cardiology setup was simulated for two models of lead glasses, five beam projections and two patient access routes. Hp(3) dosemeters were placed at several positions on the operator and the obtained dose was compared to the dose to the sensitive part of the eye lens (Hlens). Furthermore, to reproduce an experimental setup, a reference dosemeter, Hp(3)ref, was placed on the surface of the eye. The dose measured by Hp(3)ref was, on average, only 60% of Hlens. Dosemeters placed on the glasses, under their shielding, underestimated Hlens for all parameters considered, by from 10% up to 90%. Conversely, dosemeters placed on the head or on the glasses, over their shielding, overestimated Hlens, on average, up to 60%. The presence or lack of side shielding in lead glasses affected mostly dosemeters placed on the forehead, at the left side. Results suggest that both use of a correction factor of 0.5 to account for the presence of lead glasses in doses measured outside their shielding and placing an eye lens dosemeter immediately beneath the lenses of lead glasses may lead to the underestimation of the eye lens dose. Most suitable positions for eye lens dose assessment were on the skin, unshielded by the glasses or close to the eye, with no correction to the dose measured.

Occupational eye lens dose in endoscopic retrograde cholangiopancreatography using a dedicated eye lens dosimeter

“…Pb glasses with a small lead equivalent are advantageous because of their light weight. Originally, the radiation-scattering reduction rate was expected to be higher for Pb glasses with a larger lead equivalence [26]. However, in this study, 0.07 mm Pb glasses showed higher scattered ray reduction rates than 0.75 mm Pb glasses in both eyes.…”

Occupational radiation exposure to the lens of the eye in interventional radiology

“…Although it is worthy to note that the gasses provide a reduction at the point of measurement and this does not necessarily mean that the same efficiency will be provided to the eye lens, the reduction in dose by approximately 79% provided by lead glasses in clinical practice is reassuring. A number of studies have established a dose reduction factor between 3 and 6 when eye radio protective equipment is utilized, established by phantom studies 29–33 . The ICRP 15 suggests that division by a dose reduction factor of 2 for collar dosimetric measurements, would be conservative approach that could estimate the protection offered by lead glasses with a lead equivalence of 0.75 mm.…”

Assessment of eye doses to staff involved in interventional cardiology procedures in Kuwait

“…When using leaded spectacles the impact of dosimeter position on the measured dose is great. The dosimeters should be very close to the eye and unshielded by the spectacles, to avoid underestimation of eye lens dose (Honorio da Silva et al 2020). Eye dose calculation tools can be used to estimate the effectiveness of using radiation protection equipment and optimize the eye protection (Covens et al 2018).…”