Answer to Question #6517 Submitted to "Ask the Experts"
The following question was answered by an expert in the appropriate field:
What is the proper procedure for testing lead aprons for in a hospital setting?
The following sample procedure is a slight modification to the procedure offered by Rene Michel and Michael Zorn in their article "Implementation of an X-ray Radiation Protective Equipment - Inspection Program" published in Operational Radiation Safety Vol 82, Feb. 2002, pp 551-553:
While this is not an issue at hospitals, fluoroscopic equipment might not be available at smaller clinics. It is possible to radiographically examine the lead apron.
You will also want to establish some criteria for rejecting the lead apron. Lambert and McKeon ("Inspection of lead aprons: Criteria for rejection," Operational Radiation Safety Volume 80, May 2001) suggested replacing lead aprons if a defect is greater than 15 square mm unless the defect is clearly not over a critical organ. Lead aprons with defects along the seam, in overlapped areas, or on the back of the lead apron would be subject to the less conservative 670 square mm rejection criteria. Thyroid shields with defects greater than 11 square mm should be replaced. The British Columbia Center for Disease Control used a somewhat different approach and recommends rejection criteria of an aggregate area of 10 square cm over the whole body, 0.2 square cm over the reproductive region, and 1 square cm over the neck region (download its paper here).
Finally you should check your state radiation control regulations for requirements. For example, the Commonwealth of Pennsylvania has no regulations addressing lead apron inspections, but the great state of Texas does:
"Protective devices, including aprons, gloves, and shields shall be checked annually for defects such as holes, cracks, and tears. These checks may be performed by the registrant by visual or tactile means, or x-ray imaging. If a defect is found, protective devices shall be replaced or removed from service until repaired. A record of this test shall be made and maintained by the registrant in accordance with subsection (s)(1) of this section for inspection by the agency."
Note that this regulation is satisfied by a physical inspection or x-ray imaging inspection of the lead apron. This is the difference between the Michel and Zorn's procedure and the one above. The Michel and Zorn procedure recommends only performing fluoroscopic examinations of aprons suspect as a result of the physical inspection. Considering the regulation above and being able to cite a peer-reviewed article as justification, their procedure is worthy of consideration. The advantage of the procedure offered above is that it uses radiation to look for failure to attenuate radiation, i.e., it is a direct measure of the effectiveness of the lead apron. Therefore, a fluoroscopic examination may uncover some defects overlooked in a physical inspection. However, the disadvantage is the additional time to perform the fluoroscopic procedures, additional radiation dose to the inspector, and the availability of fluoroscopic equipment in busy facilities.
Kent Lambert, CHP
Answer posted on 22 June 2007. The information and material posted on this website is intended as general reference information only. Specific facts and circumstances may alter the concepts and applications of materials and information described herein. The information provided is not a substitute for professional advice and should not be relied upon in the absence of such professional advice specific to whatever facts and circumstances are presented in any given situation. Answers are correct at the time they are posted on the Website. Be advised that over time, some requirements could change, new data could be made available, or Internet links could change. For answers that have been posted for several months or longer, please check the current status of the posted information prior to using the responses for specific applications.
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