Objectives: Reducing unnecessary radiation exposure from medical imaging is paramount. This study assessed whether a laser aiming guide for C-arm fluoroscopy reduced the number of exposures needed to obtain an acceptable image, thereby reducing total fluoroscopy time for hip, knee, and ankle fluoroscopy.
Methods: An obese cadaver was placed supine on a radiolucent surgical table. Images were obtained by licensed radiologic technologists using a calibrated OEC 9900 Elite C-arm with laser targeting (LT) and without LT (NLT). Dosimeters were placed 1, 3, and 6 ft (30.5, 91.5, and 183 cm) away from the center of the C-arm at 90-degree angles at 2 levels, simulating thyroid and gonadal exposure. Posterior-anterior (PA) images of the bilateral lower extremities were obtained with each technician acquiring 24 centered images (hip, knee, and ankle) using both LT and NLT C-arm fluoroscopy.
Results: Total fluoroscopy time was reduced by 19% when using LT with a 39% reduction for the knee and a 29% reduction for the ankle. The addition of LT improved the likelihood of obtaining a centered image for knees and ankles but not for hips. The gonadal dosimetry data were significantly higher than the thyroid dosimetry badges at 1 ft. At the 3-ft zone, only trace amounts of radiation were detected; the 6-ft zone reported no radiation exposure in either group.
Conclusions: LT helped with imaging knees and ankles with statistically significant reductions in fluoroscopy time and a statistically significant improvement of image quality defined as obtaining a centered PA image faster. The dosimetry badges detected minimal exposure at 3 ft and no detectable exposure at 6 ft at both levels.