Answer to Question #12469 Submitted to "Ask the Experts"

Category: Medical and Dental Equipment and Shielding — Lead Aprons

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

Q

For the past year I have been working as a veterinary nurse and am currently exposed to approximately 50 x rays per week. While these x rays are occurring, I don't wear any protection due to my boss telling me it wasn't important. We have no radiation badge readers available. I am right next to the x-ray machine, with my head and neck very close to (but out of) the main beam, due to the necessity of holding our patients in position. On top of that, my boss has taken the cone off because he says it helps the digital x rays come out better. I have no way of measuring my exposure, and I am very worried about the effects this exposure may have on my health and cancer risks in the future. Should I be concerned?

A

The use of x-ray equipment is regulated by the state that the equipment is located in. State regulations typically indicate a minimum amount of shielding for anyone who must stay in an x-ray room during a procedure. Ohio, for example requires persons in the room to be protected by at least 0.25 mm of lead equivalent material for scatter radiation and 0.5 mm of lead equivalent material for primary beam radiation. Typically, states will have the same or similar regulations (you should verify what the regulations are for your state). Because of these regulations, no one should be in a veterinary x-ray room unless they are wearing a lead apron.

The use of radiation dosimeters is required in many or most states for anyone who is likely to receive greater than 10% of any annual occupational radiation dose limits. That is usually determined by a radiation expert who has performed a radiation survey to estimate the maximum radiation doses to workers, or simply by having personnel wear dosimeters for a period of time (6 to12 months) to determine actual doses that they receive. It is very common to see dosimeters worn in veterinary x-ray facilities, however, it is not always the case. You should discuss this with your employer, as it is possible that an evaluation has been done and it may have determined that dosimeters are not required for your facility.

State regulations also typically specify a minimum distance between the x-ray tube target and the closest location that can be placed near the patient (e.g., 30 cm). If your state has this requirement, the cone must always be in place.

Although it is unlikely that you are exceeding state radiation dose limits (which are typically set at some factor below what is considered safe), you should be wearing a lead apron which will reduce your radiation doses to levels that are as low as reasonably achievable (ALARA).

Kennith "Duke" Lovins, CHP

Reference

Ohio Administrative Code OAC 3701:1-66-02(G)(3)(a) & (b).

Ask the Experts is posting answers using only SI (the International System of Units) in accordance with international practice. To convert these to traditional units we have prepared a conversion table. You can also view a diagram to help put the radiation information presented in this question and answer in perspective. Explanations of radiation terms can be found here.
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