Protective aprons in imaging departments: manufacturer stated lead equivalence values require validation

The composition of protective aprons worn by X-ray personnel to shield against secondary radiation is changing. Lead is being replaced by either lead-free or composite (lead with other high atomic numbered elements) materials. These newer aprons are categorised by manufacturers in terms of lead equivalent values, but it is unclear how these stated values compare with actual lead equivalent values. In this work, the actual lead equivalence of 41 protective aprons from four manufacturers, all specified as having 0.25 mm lead equivalence, were investigated with transmission experiments at 70 and 100 kVp. All aprons were in current use. The aprons were screened for defects, and age, weight and design was recorded along with details of associated quality assurance (QA). Out of the 41 protective aprons examined for actual lead equivalence, 73% were outside tolerance levels, with actual levels in some aprons demonstrating less than half of the nominal values. The lack of compatibility between actual and nominal lead equivalent values was demonstrated by aprons from three of the four manufacturers investigated. The area of the defects found on screening of the protective aprons were within recommendations. The results highlight the need for acceptancy and ongoing checks of protective aprons to ensure that radiation exposure of imaging personnel is kept to a minimum.