Real-time evaluation of operator eye lens radiation dose in interventional radiology: Effects of protective shield position and X-ray beam angle

This study investigated the relationship between physician eye lens dose rate and the positioning of a ceiling-suspended protective shield during cardiovascular interventions using a biplane imaging system. A real-time dosimeter measured dose rate near the operator’s eye at 1-second intervals, and procedural videos were analyzed to evaluate the geometric relationship between the physician’s head and the protective shield. Dose rate differed significantly by beam angulation (p < 0.001), with higher values observed in caudal (CAU) projections. Horizontal displacement of the protective shield showed a strong negative correlation with dose rate during fluoroscopy (R = −0.656 to −0.829, p < 0.01) and cine acquisition (R = −0.538, p < 0.01). When the shield was positioned posterior to the physician’s head, the dose rate increased significantly, with large effect sizes. In contrast, vertical displacement showed weak or no correlation with dose rate, with low explanatory power, indicating a limited effect on lens exposure within the typical range of shield use. These findings suggest that horizontal misalignment of the protective shield, influenced by beam angle changes and operator posture, is a key determinant of physician exposure. Ensuring appropriate anterior positioning of the shield, particularly during CAU projections and after angle changes, may help reduce occupational lens dose. The combined use of real-time dosimetry and image-based positional analysis provides a practical approach for optimizing radiation protection during interventional procedures.