Development of radioprotective side shield attached to radioprotective glasses for reducing eye lens dose of endoscopists during endoscopic retrograde cholangiopancreatography: a phantom study

The use of radioprotective glasses alone may not reduce radiation sufficiently to protect the eyes of endoscopists performing endoscopic retrograde cholangiopancreatography (ERCP). In this study, we aimed to develop a radioprotective side shield that could be attached to radioprotective glasses. Air kerma was measured at the lens surface of an endoscopist phantom using optically stimulated luminescence dosimeters in an arrangement that simulated ERCP. The protective effect of the radioprotective side shield was evaluated by changing three factors: the number of sheets to be layered from 1 to 5, the front-side length of the sheet from 6 to 10 cm, and the rear-side length of the sheet from 5 to 7 cm. By increasing the front length of the sheets to 8 cm, their rear length to 6 cm, and increasing the number of sheets to three with a lead equivalent of 0.14 ± 0.02 mmPb, the air kerma on the ocular surface could be reduced considerably; hence, these changes were implemented. This achieved a dose reduction of 48.2-87.3% compared with the use of radioprotective glasses alone, especially when the endoscopist phantom was rotated 60° and 75° from the direction directly opposite to that of the patient phantom. The results suggest that radioprotective side shields can reduce radiation exposure in the eyes of endoscopists by < 0.03 mGy in 10-min fluoroscopy under most conditions during ERCP.