Answer to Question #10721 Submitted to "Ask the Experts"

Category: Medical and Dental Patient Issues — Dental

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


My son was in the dentist's office having his six-month checkup. The x-ray machine was right outside the room where he was having his checkup and the girl was pressing the button a few times even though no one was standing in front of the machine receiving an x ray. Do you know why she would press the button on the x-ray machine when no one was having an x ray?


The most probable answer is that the office was evaluating the technical settings for a direct digital sensor. Today's sensors are extremely sensitive to radiation and are measured not in tenths of seconds of radiation exposure, but in hundredths of seconds; for example, in my dental school clinic, our "standard" setting is 0.08 seconds, that is, eight hundredths of a second. And, of course, we change this for smaller patients and larger patients accordingly as needed. As a result, it does not take very much for the settings for these machines to get out of adjustment. So the technical settings for the machine could have been changed somehow and the staff member was readjusting the machine while imaging a small radiopaque object to make sure the settings were properly adjusted. Another consideration is that the office may have recently purchased a new digital sensor and was in the process of adjusting settings to determine the optimal technical settings for the machine so that the best exposures could be obtained clinically.

I hope this answer is helpful with your question!!

Jeffery B. Price, DDS, MS

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 26 June 2013. 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.