Evaluation of factors influencing eye lens radiation dose while using radiation protection glasses in interventional radiology: A phantom study.

Purpose: Radiation protection glasses reduce eye lens exposure in Interventional Radiology (IR). However, the protection ratio differs for the lead equivalent content and shape of the lenses. This study aimed to examine factors effective in reducing the lens dose by measuring the protection ratio of scattered radiation due to changes in the surgeon's face orientation, various lead equivalents, and shapes.

Method: The examination model of endoscopic retrograde cholangiopancreatography. The simulated surgeon was positioned 60 cm from the center of the X-ray irradiation, beside the patient's head at a 45° angle relative to the patient's midline. The surgeon's face angle was altered between 45° left, 0°, and 45° right with respect to the bed. Respective lens equivalent doses were compared when the same dose was reached on the DAP meter. Nine types of radiation protection glasses (lead equivalent value range [0.07-0.75 mm Pb]) were used.

Results: Single regression analysis showed a significant difference between the lead equivalent and lens equivalent dose when the surgeon's face was oriented at 0° or 45° right with standard coefficients of -0.944 and -0.963. At the 45° left orientation, a significant difference was observed between the skin and the lower gap area of the glasses, with a standard coefficient of 0.692, which is a factor in the incidence of scattered rays from the downward direction.

Conclusions: For radiation protection glasses, increasing the lead equivalent of the lenses and minimizing the lower gap between the skin and lenses were effective in reducing lens exposure.