Efficacy of Lower-Body Shielding in Computed Tomography Fluoroscopy-Guided Interventions

Abstract

Computed tomography (CT) fluoroscopy-guided interventions pose relevant radiation exposure to the interventionalist. The goal of this study was to analyze the efficacy of lower-body shielding as a simple structural method for decreasing radiation dose to the interventionalist without limiting access to the patient. All examinations were performed with a 128-slice dual source CT scanner (12×1.2-mm collimation; 120kV; and 20, 40, 60, and 80mAs) and an Alderson-Rando phantom. Scatter radiation was measured with an ionization chamber and a digital dosimeter at standardized positions and heights with and without a lower-body lead shield (0.5-mm lead equivalent; Kenex, Harlow, UK). Dose decreases were computed for the different points of measurement. On average, lower-body shielding decreased scatter radiation by 38.2% within a 150-cm radius around the shielding. This decrease is most significant close to the gantry opening and at low heights of 50 and 100cm above the floor with a maximum decrease of scatter radiation of 95.9% close to the scanner's isocentre. With increasing distance to the gantry opening, the effect decreased. There is almost no dose decrease effect at ≥150 above the floor. Scatter radiation and its decrease were linearly correlated with the tube current-time product (r (2)=0.99), whereas percent scatter radiation decrease was independent of the tube current-time product. Lower-body shielding is an effective way to decrease radiation exposure to the interventionalist and should routinely be used in CT fluoroscopy-guided interventions.