Program Information
Comparison of Air Kerma and Hp(10) for Quantifying Transmission Through Protective Garments
A Jones1*, A Pasciak2 , (1) MD Anderson Cancer Center, Houston, TX, (2) University of Tennessee Medical Center, Baltimore, MD
Presentations
SU-H1-GePD-I-4 (Sunday, July 30, 2017) 3:00 PM - 3:30 PM Room: Imaging ePoster Lounge
Purpose: To compare the use of air kerma and Hp(10) to quantify transmission through protective garments.
Methods: Current standards specify that exposure (air kerma) be used to measure transmission through protective garments when assessing their protective value. However, the use of air kerma ignores the fact that we are primarily interested in the deep dose equivalent to the wearer. This study compared transmission quantified using air kerma and Hp(10) by using Monte Carlo simulation to study a 0.5 mm sheet of lead (Pb) and equivalent radiological thicknesses of tin (Sn) and antimony (Sb) in a broad-beam geometry. Two scatter-mimicking primary beams (SMPB) corresponding to common primary beam qualities in interventional fluoroscopy were used as sources in the simulation (primary beam qualities of 72 kV + 0.2 mm Cu and 110 kV + 0.2 mm Cu)
Results: Transmission quantified using Hp(10) was consistently higher than transmission quantified using air kerma for Pb (13% - 17%). Transmission quantified using Hp(10) was lower than transmission quantified using air kerma for the 72 kV beam for both Sn and Sb (12% and 14%, respectively), and was higher than transmission quantified using air kerma for the 110 kV beam for both Sn and Sb (4% and 3%, respectively).
Conclusion: The use of exposure (air kerma) to quantify the protective value of garments underestimates transmission compared to the use of Hp(10) for Pb. The impact for non-lead materials depends on the scatter radiation quality but in both cases the impact was unfavorable compared to lead. These simulations used pure metals and did not account for the reduced efficiency per weight of these elements when used in oxide or other compound form.
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