Radiation Protection Clothing in X-Ray Diagnostics - Influence of the Different Methods of Measurement on the Lead Equivalent and the Required Mass

Abstract

Purpose: The determination of attenuation compared to lead for lead-free and lead-reduced protective clothing depends strongly on the different methods of measurement. The standards EN 61331-1 (2002), DIN 6857-1 und IEC 61331-1 (2014) are now available for the testing of protective clothing. These standards define methods in the narrow beam and in the inverse broad beam geometry with partially different radiation qualities. In the narrow beam the scattered radiation and fluorescence are not considered due to the arrangement. Therefore, the protective effect of lead-free materials will be incorrectly estimated compared to lead material. The influence of the different methods of measurement on the lead equivalent and the required mass of radiation protection clothing was examined. Materials and Methods: The lead equivalents for material samples for commercially available protective clothing were determined. These samples were made of lead and lead-reduced and lead-free materials. For determination of the attenuation equivalents, certified lead foils with high purity and a precise thickness of 0.05 to 1.25 mm were used. Results: The measurements indicate that the lead equivalent depends on the method of measurement and the radiation quality. For X-ray tube voltages below 110 kV, lead-free or lead-reduced materials show a higher lead equivalent compared to lead material in some cases. Significant mass reductions of more than 10 % compared to lead material are only achievable with a limited range of use up to 100 kV. Conclusion: The implementation of an internationally accepted measuring standard for radiation protection clothing is reasonable and necessary. If standard IEC 61331-1 (2014) can fill this role is unknown.