Eye lens dose and shielding efficacy of radiation-protective eyewear in C-arm-guided cervical and lumbar epidural blocks: a phantom study

초록

Epidural blocks are commonly performed interventional pain procedures under C-arm fluoroscopic guidance. However, radiation exposure to the ocular lens remains a significant concern due to its high radiosensitivity and the associated risk of radiation-induced cataract formation. Therefore, this study aims to quantify ocular lens dose during cervical and lumbar epidural blocks (CEBs and LEBs), and to evaluate the shielding efficacy of 0.5 mmPb lead-free radiation-protective eyewear (R-PEW), using a quantitative, phantom-based experimental design that simulates realistic clinical scenarios based on exposure conditions derived from 150 real patients. An adult anthropomorphic phantom was used, and ocular lens doses were recorded with optically stimulated luminescence dosimeters under six experimental conditions defined based on procedure type, patient position, and eyewear status. Without shielding, the maximum lens dose was 1.90 mSv during prone CEBs, while the greatest reduction with R-PEW was 83.3% during prone LEBs. Dose asymmetry between the right and left eyes corresponded to differences in source-to-eye distance. All measured doses were substantially below the cataract threshold (0.5 Gy) and the International Commission on Radiological Protection annual public equivalent dose limit for the lens of the eye (15 mSv). Nonetheless, R-PEW consistently reduced exposure under all conditions, offering additional protection in accordance with the optimisation principle. These findings suggest that, although routine patient shielding is not warranted given the low absolute doses, R-PEW represents a simple and effective adjunct to further minimise ocular exposure during C-arm-guided epidural blocks.

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