Answer to Question #2939 Submitted to "Ask the Experts"

Q

Recently, my four-year-old son received six dental x rays. I was in the room with him and was asked to push the button to take the x rays while the dental hygienist was holding the bitewings inside his mouth. I was not wearing a lead apron during this time. I'm assuming that the dental hygienist was sure to have lead protection on herself, as she takes x rays all day long. My son also had lead protection on. I did read the statement about lead aprons and how improvements in technology have made x-ray dosage much improved, making the absence of a lead apron or vest not terrible. I still have concerns about what I have read about scattered rays from a given x ray which I would have been exposed to during that time. It was recently discovered that I have a fluid-filled cyst in my breast, and I am concerned if any radiation exposure would be more apt to affect this area, or if a cyst would be more vulnerable to exposure, or more likely to become cancerous after any exposure to radiation. Can you tell me if my concerns are warranted?

A

The answer to this question is provided as two separate sections.

It is not routine practice for a dental hygienist to hold the x-ray films in the patient's mouth and have the parent or another individual make the x-ray exposure. This is primarily because in most, if not all, states it is not legal for individuals to make x-ray exposures unless they are a physician or have a state license to take x rays. It is possible that for some patients, it is difficult to hold the bitewing films in one place during the exposure. If this is the case, it is more appropriate for the parent to help with stabilizing the patient, while being provided shielding and ensuring that no part of the holder's body is in the x-ray beam, and the dental hygienist to take the x rays. In a sense, it was admirable on the dental hygienist's part to reduce your exposure. However, the dental hygienist is the one taking x rays all day long and would be more likely to receive more radiation exposure in a year than you would.

Since you did not state where you were standing when you made the exposures, I will assume that you were outside the room, perhaps in a hallway. It is likely that you were 6'-10' away from the x-ray tube and there may be shielding in the wall with the control switch. Even though you did not have on a lead apron, due to the distance and possible structural shielding, the radiation exposure that you received would be very small, perhaps on the order of a few millirem. Typically, most individuals in the Unites States receive approximately 360 mrem of background radiation each year from things such as radon and naturally occurring radiation in rocks and from space.

As far as unauthorized x-ray machine operators or patients not wearing lead aprons on occasion, this is considered poor practice. Even though the dose to a technologist or a patient may be low or only occasional, all facilities that use radiation for medical uses should operate under the ALARA philosophy. This means that radiation doses should be kept As Low As Reasonably Achievable by using standard methods such as lead aprons, having the control switch farther away from x-ray tube or in a shielded area, and only taking necessary x-rays exams. ALARA should be used while still obtaining the necessary information for the patient's caregiver.

In regard to your question about a fluid-filled cyst in the breast, a review of the radiobiology literature indicates that typically, breast cancer arises in duct cells. It is unlikely that a fluid-filled cyst would be more sensitive to radiation exposure or that exposing it to radiation would lead to cancer development. In any case, based on the amount of radiation that you may have received, the likelihood of developing any cancer is very low and should not cause you to worry since it may take tens of thousands of millimrem (or considerably more) to possibly cause a cancer.

Ken "Duke" Lovins, CHP

Editor's Note: In any submission relating medical questions, the Health Physics Society recommends that you discuss these issues with your physician.