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 the 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 over 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 (postgraduate year [PGY]6) and final 6 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 body mass index were recorded. Scatter fractions were measured with the thyroid and sternum counts to DAP ratio and the DAP/RAK ratio (a surrogate for collimation and use of magnification). Paired Wilcoxon and χ² 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 PGY6 fellows and 19 cases with PGY7 fellows. Higher median thyroid and sternum radiation doses were observed for PGY6 fellows than for PGY7 fellows, respectively (82 μGy [interquartile range (IQR): 47-94 μGy] vs 44 μGy [IQR: 30-57 μGy], P = .009; 89 μGy [IQR: 75-128 μGy] vs 54 μGy [IQR: 48-77 μGy], P = .007). Scatter fractions, as measured by the thyroid/DAP and sternum/DAP ratios, were significantly higher for first-year fellows (2 vs 1, P = .018; 2.64 vs 1.23, P = .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 PGY6 and PGY7s is likely enhanced for vascular residents (PGY1-5) and further underscores the importance of early and thorough education in radiation safety for all trainees.