Analysis of Radiation Exposure Learning Curves for Vascular Surgery Trainees During Fluoroscopically Guided Interventions.

Abstract

Objective: The volume of fluoroscopically guided interventions (FGIs) performed by vascular surgeons has increased significantly nationwide, however appropriate and timely radiation safety training varies by institution. Vascular surgery trainees often learn radiation safety techniques concurrently with learning the art of vascular surgery. Given the concern for occupational hazards throughout clinical training, we sought to determine the radiation dose exposure to trainees, faculty surgeons and patients during FGIs according to level of training.

Methods: A prospective cohort study was performed at a university hospital to determine the median body radiation dose of trainees, attending surgeon and patients during FGIs during a 5-month period. Optically stimulated luminescence dosimeters were placed outside the lead apron at the thyroid and sternum positions for one attending surgeon and all assisting fellows performing FGIs. Cases were stratified according to fellow training stage: first 6 months in the first year (PGY6) and final six months of the second year (PGY7). Operator radiation dose was calculated based on a calibration of 80 kVp. Procedural reference air kerma (RAK), fluoroscopy time, dose area product (DAP) and patient BMI were recorded. Scatter fractions were measured with thyroid and sternum counts to DAP ratio, and DAP/RAK ratio (a surrogate for collimation and use of magnification). Paired Wilcoxon and chi-square tests were performed to identify statistical significance of training stage on radiation dose exposure and performance of radiation reduction.

Results: A total of 40 FGIs were performed: 21 cases with PGY-6 fellows and 19 cases with PGY-7 fellows. Higher median thyroid and sternum radiation doses were observed for PGY-6 fellows compared to PGY-7 fellows, respectively (82 μGy [IQR 47-94] vs 44 μGy [IQR 30-57], P=0.009; 89 μGy [IQR 75-128] vs 54 μGy [IQR 48-77], P =0.007). Scatter fractions as measured by the thyroid/DAP and sternum/DAP ratios were significantly higher for first-year fellows (2 vs 1, P = 0.018; 2.64 vs 1.23, P = 0.041). There was no difference in the source to image distance or the average field size as measured by the DAP/RAK ratio.

Conclusions: Trainee radiation dose exposure is higher during the first year of fellowship. Acquisition of optimal performance with fluoroscopy skills can be related to training time. The difference noted between PGY 6 and PGY 7s is likely enhanced for vascular residents (PGY 1-5) and further underscores the importance of early and thorough education in radiation safety for all trainees.