By Stephen Marshall
We all know the dangers of radiation, and how important it is to keep our exposure to it to a minimum. Lead aprons are the single most important line of defence against radiation in a clinical environment. Everyone working within a Theatre, Cath Lab, Fluoroscopy room or anywhere where medical radiation is present should be wearing at least a lead apron and thyroid collar, some members of staff may also utilise lead glasses or other safety features. But despite being such an important safety feature, how often are you screening your lead aprons in your department to check for faults?
In the U.K there is no hard rule about how often lead aprons should be screened, most hospitals will check their aprons annually, but some will check them every six months. Before you start you should assign each lead apron and thyroid shield a number and record all of the findings in a suitable database, such as ‘X-Ray Track’. There are three main inspection methods that are used to check lead aprons, all of which should be used in conjunction with each other.
The first method is to visually inspect the equipment, lay the apron on a flat surface, and visually inspect the apron for tears, clumps of lead, broken fasteners etc.
The second method is to feel the apron with your hands, check for signs such as thinning of lead in certain areas, creasing within the apron, and any other signs that might require further inspection. You can use the method when the apron is hung up on a storage rack or you can lay it down on a flat surface.
The third and most thorough method of screening is to take x-rays of the aprons or ideally undertake a fluoroscopic examination of the apron. If you don’t have access to fluoroscopy equipment you can utilise a normal x-ray tube. First you should inspect the lead apron using the two previously mentioned techniques. After that take radiographs of the aprons using a high kV and low mA in an attempt to penetrate the apron without damaging the machines x-ray tube. You should be looking out for any breaks in the lead lining of the apron,they would typically appear as bright slashes as shown in the below picture.
If you have access to Fluoroscopy this is the preferred choice. Lay the items on the Fluoro table and screen the entire item using manual settings. You should aim to use a fairly high kV such as 80 or 100, while keeping the mA low so you don’t damage the x-ray tube. If you don’t use manual settings the machine will try and penetrate the thick lead apron, and this could result in harm to the x-ray tube. Again, shielded areas will appear dark, and defects will appear light as the x-rays are getting through this area.
There’s debate on how big the crack in the lead should be before the lead apron or thyroid shield is replaced. But a recent study titled “Inspection of Lead Aprons: A Practical Rejection Model” by Drs. Pillay and Stam (Health Physics, volume 95, No. 2, August 2008)” suggested that tears greater than 5.4cm in length are cause for rejection. The study also added that if the tears were near a radiosensitive area such as the gonads or thyroid, then the apron or shield would have to be rejected if the tear was over 1.7cm in length.
How to protect your lead apron from damage
There are a few easy ways to prolong the life of your lead apron.
-Firstly, make sure your aprons are stored appropriate way in between use. They should be hung on a specifically designed apron rack.
-Avoid exposure to extreme temperatures or sharp objects.
-Don’t wear your lead apron while sitting.
Follow this easy guide to keep your department safe, and your protective equipment in top shape. If you do find you have any cracks contact Rothband on +44 (0) 1706 830086 or alternatively send them an email at firstname.lastname@example.org