The Risk of Elevated Radiation Dose in Complex Endovascular Procedures: Surgeon Education Improves Patient Safety
Melissa L Kirkwood, Gary M Arbique, Jeffrey B. Guild, Carlos Timaran, R. James Valentine, Jayer Chung, Jon A Anderson
UT Southwestern Medical Center, Dallas, TX
Background: Complex endovascular procedures (CEP) such as fenestrated endovascular aneurysm repair (FEVAR) are associated with higher radiation doses compared to other fluoroscopically-guided interventions (FGI). The purpose of this study was to determine whether surgeon education on radiation dose control can lead to lower reference air kerma (RAK) and peak skin dose (PSD) levels in high-dose procedures.
Methods: Radiation dose and operating factors were recorded for FGI performed in a hybrid room over a 17-month period. Cases exceeding 6 Gy RAK were investigated according to institutional policy. Information obtained from these investigations led to surgeon education consisting of personalized instruction as well as a one hour lecture focused on reducing patient dose. Points addressed included increasing table height, utilizing collimation and angulation, decreasing magnification modes and maintaining minimal patient to detector distance. Procedural RAK doses and operating factors were compared 8 months pre and 8 months post educational intervention using ANOVA with Tukey pairwise comparisons and T tests. Peak Skin dose (PSD) distributions were calculated using custom software employing input data from fluoroscopic machine logs.
Results: Of 447 procedures performed, 300 FGI had sufficient data to be included in the analysis (54% Lower extremity, 11% TEVAR, 10% Cerebral, 8% FEVAR, 7% EVAR ,5% Visceral, and 5% embolization). 20 cases were further investigated for exceeding 6 Gy RAK (14 FEVAR, 3 embolization, 1 EVAR, 1 TEVAR, 1 visceral). FEVAR represented only 8 % of cases performed; however, FEVAR comprised 70% of the cases investigated for reaching 6 Gy RAK and had 5 times the average RAK dose compared to all other FGI performed (p<0.0001). Degree of fenestration ranged from one to four vessels and there was no difference in RAK dose based on number of vessels fenestrated. The effect of surgeon education on radiation dose was seen in all cases, regardless of complexity. Compared to the pre-education data-set, the post-education table height was 10cm higher on average (p<0.0001) per case resulting in an estimated 15% reduction in PSD. Additionally, the use of collimation also increased from 25% to 40% (p<0.001) for all cases, further reducing PSD. There was no observable change in other operating factors including the use of magnification, or angulation. The number of cases that exceeded 6 Gy RAK did not change after education; however the proportion of non FEVAR cases that exceeded 6 Gy decreased from 40% to 20%.
Conclusion: These data show that radiation doses associated with FEVAR are significantly greater than doses associated with all other FGI. Surgeon education focused on good fluoroscopic operating factors can lower patient PSD; therefore, vascular surgeons must not only be aware of the potential for high radiation dose in CEP but also be vigilant in efforts to reduce exposure to themselves and the patient.
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