Answer to Question #12152 Submitted to "Ask the Experts"

Category: Medical and Dental Patient Issues — Diagnostic X Ray and CT

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

Q

I have had multiple dental x rays at a dental surgeon's office where I started receiving care a little more than a year ago. They appear to have an expensive, sophisticated x-ray machine. It provides what generally looks like panoramic-type x rays but is also used for single-tooth x rays. The issue is that each time I stand up to the machine, the staff have me place the lead apron on backwards with a small strap around my neck holding the apron in place. The last time I had an x ray done, I had to remind the staff member to provide me with the lead apron, and again the lead apron was placed across my back. I am older and not of child-bearing age anymore, yet I do care about my radiation exposure at any level. Is placing the lead apron backwards appropriate for a panoramic dental x-ray machine? My previous experiences with x rays have not been like this.

A

This is an excellent question with an interesting answer—but briefly, this is an appropriate way to place a lead apron. Also, you have every right to be concerned about radiation safety, and you should be exposed only to the amount of radiation necessary to make a medical or dental diagnosis and no more.

The general purpose of the lead apron as used on the patient is to protect the patient from scattered x rays. Panoramic style x-ray machines rotate around the patient's head with the x-ray source rotating around the side and back of the head and the image receptor, or film, on the side and front of the head. Having the lead apron positioned on the patients' back in this arrangement prevents a greater amount of x-ray scatter reaching the patient as compared to having the lead apron positioned on the front of the patient.

In addition, there are panoramic lead apron "vests" available that have a long portion for the back as well as a short portion for the front of the patient. These are convenient to use since they open from the side and easily drape on the patient using a side delivery.

Finally, we have an occasional request from a patient to use a thyroid collar during a panoramic exposure. While using thyroid collars is an excellent method to reduce radiation exposure during intraoral examinations, they block a portion of the x-ray beam during panoramic exposures and introduce artifacts and additional x-ray scatter. This usually results in a nondiagnostic image that has to be retaken.

Jeffery B. Price, DDS, MS
Clinical Associate Professor and Director of Oral Radiology
Diplomate American Board of Oral & Maxillofacial Radiology
Diplomate International Congress of Oral Implantologists
Master Academy of General Dentistry
Fellow American Association of Hospital Dentists

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