Lead equivalent personal protection equipment

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Lead equivalent personal protection equipment (PPE) should be available in all radiology departments and operating suites. There are three traditional principles for ionizing radiation safety: time, distance, and shielding. It is important to remember that all three principles have a part to play in ensuring radiation safety. This article discusses some of the shielding options that should be available but it is equally important to be aware of the inverse square law and the duration for which persons are exposed to radiation. However, as front scatter and back scatter get created from all scattering objects (this refers to anything that also attenuates the radiation) change the pattern it is important to understand radiation dose as every person or object in the room impacts the dose.

Lead aprons

Lead aprons are one of the key parts of personal radiation protection equipment along with lead gloves, lead glasses, and thyroid shields.

In medical imaging, there are two main types :

  • 0.25 mm lead equivalence
    • weighs 1-5 kg ("lightweight apron")
    • attenuates 75% of the x-ray beam at 50 kVp
    • attenuates 51% of the x-ray beam at 100 kVp
  • 0.5 mm lead equivalence
    • weighs 3-7 kg ("heavy apron") 
    • attenuates 99.9% of the x-ray beam at 50 kVp
    • attenuates 75% of the x-ray beam at 100 kVp

0.35 mm lead equivalent aprons are also in use, with performance between the 0.25 and 0.5 mm lead equivalent aprons. The choice between the different aprons lies between the balance of radiation protection and injury from wearing a heavier apron.

Lead aprons should be stored on appropriate racks, and avoiding folding or creasing as this will crack the lead, and should be tested annually to assess for cracks .

Lead glasses

Lead glasses are another important piece of radiation protection and should be used by radiation users/workers in the operating suite or other areas where radiation is being used, such as the cardiac catheterization lab or angiography room.

Lead glasses have a higher lead equivalency than lead aprons and are usually 0.75 mm of lead equivalence.

As the lens of the eye is susceptible to cataracts which is a deterministic effect of radiation it is extremely important to protect the eyes from radiation.

Thyroid shields

Thyroid shields should be worn whenever a lead apron is used and should be worn quite tightly. Despite a general awareness that the thyroid gland is sensitive to radiation, studies have found there are no clear protocols for thyroid shield use . It is worth noting that not all personal protection equipment (PPE) is equal in efficacy and the rating should be checked before use .

Lead gloves

Lead gloves should be used when the user's hands are close to the primary beam in fluoroscopy-guided interventions. Lead gloves can attenuate the primary beam from 25.8-26.5% . Many users who need to be this close to the patient during fluoroscopy-guided procedures require the dexterity of their fingers for the procedure however and may not be able to use such gloves which are invariably bulky. In these cases, the user must make sure their hands are not in the beam for any longer than is absolutely necessary.