Answer to Question #11092 Submitted to "Ask the Experts"

Category: Medical and Dental Equipment and Shielding — Shielding

The following question was answered by an expert in the appropriate field:

Q

We have an operating room staff member who wears only a lead vest when assisting in fluoroscopic procedures. She insists this is adequate as she no longer worries about anything below the waist, (she can't have children). Is this adequate protection? I told her that the skirt would still provide protection to organs as well as femurs.

A

What you told this individual is correct. While many individuals think about the risk of effects to their offspring as the primary concern, that really isn't the case. The likelihood of heritable effects at the scattered radiation levels associated with fluoroscopy is insignificant, even if she could have children. As you pointed out, the lead skirt will protect the organs in the lower abdomen and pelvis as well as the bone marrow and bone surfaces of the femurs.

Only wearing the lead vest could be a regulatory concern. I suspect most regulators would frown upon an individual not wearing the lead skirt along with the lead vest. For example, an excerpt from the State of Indiana regulations (ISDH) 410 IAC 5-6.1-118, "General Requirements for Operation of X-Ray Equipment," which applies to individuals in rooms where radiographic or fluoroscopic procedures are being performed states: "(2) Staff and ancillary personnel shall be protected from direct scattered radiation by protective aprons or whole body protective barriers of not less than twenty-five hundredths (0.25) mm lead equivalent." I suspect a regulator would recognize a difference between a lead "vest" and a "protective apron." In the context of the sentence, a lead "vest" neither provides the same amount of protection as an "apron," nor does it come close to protecting the whole body. State regulations vary, so you can certainly review your state regulations and ask for an interpretation of those regulations as they apply to the situation you describe.

Some states allow for the calculation of the "effective dose (E)" or the "effective dose equivalent (EDE)" based upon multiplying the unshielded personnel monitoring badge reading by a correction factor. Such calculations allow one to correct for the protection provided by lead aprons or lead vests and skirts. These calculations are described in NCRP Report No. 122 (NCRP 1995). In that report, reference is made to "protective aprons" which were more common than lead vests and skirts at the time the report was published. Since lead aprons typically cover the parts of the body from the base of the neck to approximately the knee, it stands to reason that the calculations in that report would only be applicable to individuals wearing protection that covers that area. If only a lead vest is worn, such calculations would underestimate E or EDE.

Mack L. Richard, MS, CHP
 

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