Lower Leg Radiation Dose to Vascular Surgeons during Fluoroscopically Guided Interventions is Effectively Reduced by Wearing Leg Wraps
Bala Ramanan, Alejandro Pizano, Carlos Timaran, Michael Siah, Shadman Baig, Micheal Shih, Jeffrey Guild, Melissa L Kirkwood
University of Texas Southwestern Medical Center, Dallas, TX
BACKGROUND: The intensity of radiation scatter that emanates from the x-ray beam during fluoroscopically guided interventions is greater below the fluoroscopy table than above. Yet interventionalists’ lower legs are typically unshielded, and table skirts are often positioned incorrectly. We sought to characterize the efficacy of the leg protector wraps (Leg Wraps, Burlington Medical Inc.) in reducing the radiation dose to the operator’s lower leg during fenestrated and branched endovascular aneurysm repair (F/BEVAR).
METHODS: A prospective cohort study was performed evaluating the lower leg radiation dose reduction of one vascular surgeon during F/BEVAR using antimony/bismuth Enviro-Lite™ leg wraps (0.35 mm lead equivalency - 99.7% attenuation at 50 kVp; Burlington Medical, Hampton Roads, VA). Optically Stimulated Luminescence (OSL) nanodot™ detectors (microSTAR?ii System, LANDAUER?, Inc., Glenwood, IL) were placed inside and outside the left leg wrap at the anterior tibial tuberosity position to compare operator leg dose with and without this additional protection. The table-mounted lead skirt was used consistently in all cases. The nanodot detectors were cross calibrated with a survey meter (RaySafe X2 survey sensor, Fluke Biomedical, Cleveland, OH) by measuring scattered radiation at a position equivalent to an operator’s mid-tibia while performing digital acquisitions of a 25cm thick, 30cm x 30cm acrylic phantom with a Philips FD20 fluoroscope (Philips Healthcare, Best, The Netherlands) with the table skirt removed. The measured radiation doses were converted to skin dose, Hp(0.07), assuming an RQR6 beam spectrum (IEC-61267). Paired Wilcoxon test was performed to identify significant attenuation of radiation exposure.
RESULTS: Leg dose measurements from 14 endovascular aortic aneurysm procedures were analyzed. The patients had a median (IQR) body mass index of 30.4 kg/m2 (26-32). Median procedure reference air kerma (RAK) was 1.121 mGy (IQR = 871-1.699, min-max = 821-10.732), kerma-area product (KAP) was 140 Gycm2 (IQR = 102-196, min-max = 46-405) and fluoroscopy time (FT) was 68 min (IQR = 48-98, min-max = 28-286). The median skin dose, Hp(0.07), without leg wraps was 53 ?Sv (IQR = 30-88, min-max = 17-157), and with leg wraps was 4.1 ?Sv (IQR = 1-12, min-max = 0.5-18). The leg wraps attenuated the radiation dose 91 % (IQR = 83-97, min-max = 56-99, P<.001). The unprotected Hp(0.07) per kerma-area product was determined to be 0.4 ± 0.2 ?Sv/Gycm2.
CONCLUSIONS: The leg wraps significantly decreased scattered radiation to the lower leg during F/BEVAR. Protective leg wraps should be recommended to operators performing complex fluoroscopically guided procedures.
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