Operator eye doses during computed tomography fluoroscopic lung biopsy.

The aim of this work was to examine the peak entrance surface air kerma (peak ESAK) to the eyes during CT fluoroscopy lung biopsy, and the impact of lead glasses, exposure parameters, head rotation, and height on peak ESAK to the eyes. Two phantoms simulating the patient and radiologist were used, and 108 exposures were made using a 16-slice Toshiba Alexion CT scanner (Toshiba Medical Systems, Nasu, Japan). ESAK to the phantom radiologist's right eye was measured using an Unfors Xi dosimeter (RaySafe, Billdal, Sweden) with and without lead glasses at two kilovoltages (120 kVp and 135 kVp) and three milliampere settings (10 mA, 20 mA, and 30 mA. A paired t test was used to compare peak ESAK to the eye at different angles, heights, and kVp and mA with and without lead glasses. Peak ESAK was higher without compared to with lead glasses (p  ⩽  0.001). The peak ESAK to the eyes increased as the phantom radiologist rotated toward the gantry without lead glasses, from 2.42 μGy at 120° to 10.54 μGy at 30° (p  =  0.001). No significant difference was noted in peak ESAK with change in phantom radiologist height (p  >  0.05). An increase from 120 kVp to 135 kVp resulted in 23% and 26% increases in peak ESAK with and without lead glasses respectively (p  =  0.001). An increase of tube current from 10 mA to 20 mA almost doubled peak ESAK (p  =  0.005). Findings demonstrate that lead glasses reduce ESAK to the eyes, and that increased kVp, mA, and eye rotation to the gantry increase ESAK to the eyes.