Answer to Question #10114 Submitted to "Ask the Experts"

Category: Medical and Dental Equipment/Shielding — Shielding

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

I work in a dental clinic where the machine for Panoramic x rays is placed in the same room where there are other activities continuously performed (e.g., administrative activities, etc.). Everyone comes out of the room during x rays, but otherwise there is always someone in the room. Is there a risk with remaining radiation in the room? What kind of protection should this room have?
X rays are only present in the room during the period of time that the x-ray unit is energized to produce x rays. In the case of a panoramic dental unit, that time period is on the order of 10 to 15 seconds per exposure (i.e., per patient). As soon as the exposure is complete, there is no more radiation present in the x-ray machine, the room, or any surrounding areas.

Since this unit is located in a room where other persons work, it is important to follow any regulations regarding this installation, which would likely include having all other persons leave the room during x rays, which is what you stated is being done.

Any shielding designed into the room where this x-ray unit is located is there to protect persons in surrounding areas from exposure to radiation when the x-ray unit is producing x rays. Since there is no additional radiation produced after the exposure is complete, there is no additional shielding needed beyond what is used to protect persons in the surrounding areas.

Kennith “Duke” Lovins, CHP
Health Physicist
Answer posted on 9 February 2012. 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.