Answer to Question #11492 Submitted to "Ask the Experts"

Category: Medical and Dental Patient Issues — Dental

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

Q

I had a panoramic x ray. The bite blocker was positioned at the roof of my mouth with my mouth over the top of it, and the x ray was taken. I now have lost most of my scalp hair and have had no regrowth. I have a red rash on the skin of my neck and chest. I also have a lot of inflammation, extremely dry skin, and eye problems. Could I possibly have been exposed to radiation?

A

You asked whether you were exposed to radiation, but the better question is were you exposed to amounts of radiation that could cause the injury you describe. Panoramic dental images are associated with low patient doses—much, much lower than doses that would cause the injury you describe. Also, the part of your anatomy which would receive the highest dose would be the jaw. Therefore, injury to the entire scalp, neck, and chest are not consistent with a panoramic image.

The design of dental panoramic x-ray machines is such that only a very narrow beam of x rays is emitted from the machine as it moves around the head. The height of this narrow beam is limited to about 20 centimeters (cm), just enough to cover the entire jaw region, by a built-in lead device called a collimator. When the bite block is used to position the patient in the machine, it is not possible for the x-ray beam to expose the scalp region or chest.

Dental panoramic radiographs require the smallest amount of radiation of any dental imaging examination other than a single-view orthodontic radiograph (White and Pharoah 2014). Doses to the eyes during panoramic imaging have been measured, and they are close to zero.

The symptoms you describe (hair loss, redness, rash, dry skin, etc.) can be seen with extremely high doses of radiation—the amounts used to treat cancer (entailing daily high doses for five to six weeks). If you have not been exposed to therapeutic radiation, you may want to consult with your physician to determine other possible causes for your symptoms.

Sharon L. Brooks, DDS, MS

Reference
White SC, Pharoah MJ. Oral radiology: Principles and interpretation. 7th ed. St. Louis, Missouri: Elsevier Mosby; 2014.

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.
Answer posted on 29 March 2016. The information posted on this web page is intended as general reference information only. Specific facts and circumstances may affect the applicability of concepts, materials, and information described herein. The information provided is not a substitute for professional advice and should not be relied upon in the absence of such professional advice. To the best of our knowledge, answers are correct at the time they are posted. Be advised that over time, requirements could change, new data could be made available, and Internet links could change, affecting the correctness of the answers. Answers are the professional opinions of the expert responding to each question; they do not necessarily represent the position of the Health Physics Society.