Radiation Exposure to the Thyroid, Groin and Eyes in Seated Orthopaedic Surgeries with Real-Time Clinical Correlations

Background Fluoroscopic imaging is indispensable in orthopaedic surgery but exposes surgeons to scatter radiation. Protective lead gowns reduce exposure, but differences in gown design, C-arm orientation, and seated positioning may influence protection efficiency at critical anatomical sites. Eye exposure is of particular concern due to the revised occupational dose limit of 20 mSv/year by the International Commission on Radiological Protection (ICRP). This study aimed to quantify scatter radiation exposure at the eye, thyroid, and groin under different gown configurations and positions during seated fluoroscopy. Our study was the first study to incorporate clinical parameters and settings into our study design. Methods Radiation exposure experiments were performed using a standardized C-arm fluoroscopy setup (46 kVp, 0.61 mA) with a full-sized mannequin seated at an orthopaedic surgical arm table. Raysafe i3 dosimeters were placed externally (outside gown) and internally (beneath gown) at the eye, thyroid, and groin. Two protective gowns were tested: a two-piece skirt–vest and a one-piece cross-back gown. Three seated positions were evaluated: (i) upright with knees 15 cm apart, (ii) inverted C-arm with knees 15 cm apart, and (iii) upright with knees 45 cm apart. Continuous fluoroscopy was applied for 1, 3, and 5 minutes. Mean values were analyzed using two-way ANOVA (gown × position) and regrouped for upright versus inverted C-arm comparisons, with effect sizes (η², Cohen’s d ) calculated. Results Internal eye doses ranged from 0.1–3.8 µSv with the one-piece gown and 0.2–1.7 µSv with the two-piece gown, corresponding to 19–91% reductions compared to external measurements. Two-way ANOVA showed that position significantly affected internal eye dose (F(2,14) = 7.93, p = 0.005, η² = 0.51, large), while gown type had no significant effect (F(1,14) = 1.28, p = 0.276). External eye doses were not significantly influenced by either factor. When regrouped by C-arm orientation, inverted positioning produced significantly higher internal eye doses (F(1,16) = 16.59, p = 0.0009, Cohen’s d = − 2.04, very large). External doses trended higher in inverted orientation but were not statistically significant (F(1,16) = 2.56, p = 0.129, d = − 0.80). Internal thyroid and groin exposures were consistently 0 µSv across all conditions, corresponding to complete protection, while external values increased with time and position. Conclusions Protective lead gowns provided complete shielding at the thyroid and groin, but ocular exposure remained strongly dependent on C-arm orientation and body positioning. The inverted C-arm significantly increased ocular dose despite gown use, underscoring the vulnerability of the lens to scatter radiation. Gown design alone did not significantly alter protection to the eyes. These findings support strict adherence to upright C-arm orientation whenever feasible, routine thyroid collar use, and adoption of lead glasses to further reduce ocular risk. Optimizing fluoroscopic setup and reinforcing protective practices remain essential to minimizing occupational radiation hazards in orthopaedic surgery. This study is the first to evaluate scatter radiation exposure using clinically measured, real-time surgeon positioning during seated orthopaedic fluoroscopy.