The effectiveness of lead aprons in reducing radiation exposures from specific radionuclides

2205 Objectives: The use of lead aprons in a clinical nuclear medicine setting may be an important component in the overall ALARA program. Our department evaluated the effectiveness of lead aprons in reducing radiation levels for various beta and gamma emitting radionuclides utilized in nuclear medicine. Methods: The following radionuclides were evaluated: Y-90, a pure high energy beta emitter; I-131, a mixed gamma and beta emitter; F-18, a high energy gamma emitter; Tc-99m, a low energy gamma emitter. Four thermoluminescent dosimeters (TLD) (3x3 mm) were utilized for each specific radionuclide; two located on the anterior and two located on the posterior of a lead apron (0.5mm Pb equivalent). TLD chips were exposed for 49 to 57 minutes at an approximate distance of 2 cm from the specific radionuclide. After exposure, TLD chips were collected and sent for radiation readouts (Landauer Inc, Glenwood, IL). Results: The mean radiation levels for Y-90, anterior and posterior to a lead apron, were 212764 mrads and 379 mrads, respectively, resulting in a 99.8% attenuation of the initial radiation levels. For I-131, the mean radiation levels anterior and posterior to a lead apron were 26770 mrads and 12684 mrads, respectively, resulting in a 52.6% attenuation of the initial radiation dose. The mean radiation levels for F-18 were 13786 mrads and 11279 mrads on the anterior and posterior surface of a lead apron, respectively, resulting in an 18.2% attenuation. The mean radiation levels for Tc-99m, anterior and posterior to a lead apron, were 19663 mrads and 3404 mrads, respectively, resulting in an 82.7% attenuation of the initial radiation. Conclusions: Lead aprons were effective in reducing radiation exposure levels from a low energy gamma emitter (Tc-99m, 82.7% attenuation) and a pure beta emitter (Y-90, 99.8%), less effective in reducing radiation levels from a mixed beta and gamma emitter (I-131, 52.6%) and not very effective in reducing radiation exposures from a high energy gamma emitter (F-18, 18.2%).