Quantifying per-event dose-equivalent rates of echocardiographers and interventional cardiologists during structural heart interventions

Echocardiographers (ECs) often stand close to the patient during structural heart interventions (SHIs) and may receive higher occupational radiation exposure than interventional cardiologists (ICs). Previous studies have relied on cumulative dose measurements, leaving the per-event determinants of occupational radiation dose poorly characterized. We quantified the per-event personal dose equivalent rate at a 10-mm depth [H_p(10)] for ECs and ICs during SHIs and identified its determinants. We prospectively analyzed 37 SHI cases (20 mitral transcatheter edge-to-edge repair procedures and 17 left atrial appendage occlusion procedures) at a single center between March 2024 and March 2025. The EC and IC each wore two semiconductor dosimeters (on the front and side of the neck) sampling at 1 Hz, and the higher reading was used for analysis. Per-event H_p(10) rates were calculated by integrating dosimetry data, radiation dose structured report information, and video-based shielding labels. A prespecified linear mixed-effects model with a case-level random intercept assessed X-ray output, beam geometry, operator shielding, and C-arm angulation as candidate determinants for each operator. Among 3,222 exposure events, the EC-to-IC ratio of the H_p(10) rate was 2.3 during fluoroscopy and 3.8 during cine acquisition (both p < 0.001). In the multivariable model, log₁₀(K_a,r rate), protocol, C-arm angle, source-to-detector distance, field of view, and operator shielding were independent predictors of the H_p(10) rate for both operators. The EC experienced substantially higher per-event H_p(10) rates than the IC, particularly during cine acquisition. Operator-specific shielding strategies and per-event optimization of X-ray output are warranted.