Answer to Question #12200 Submitted to "Ask the Experts"
The following question was answered by an expert in the appropriate field:
Our orthodontist has a button on his wall that says "X Ray" (it's silver and looks like a light switch with a button in the center). What type of safety features, if any, would there be to make sure this button does not get pushed accidentally? Is the x-ray machine locked when it is not in use (not aimed towards a patient), so that if this button is pushed, no radiation comes out? It looks like the x-ray unit may be able to be attached to the wall and removed from the wall, but I have always seen it attached to the wall. There is one of these x-ray units in a private room and one in a large room with about six dental chairs.
The x-ray units that you are referring to are intraoral units, which are designed to take x rays of a few teeth at a time. They are mounted on the wall, and the arm extends over to the patient for the x ray. It is very common for these units to have exposure switches mounted outside of the room, usually in a hallway, with a push-button switch as you mentioned. The exposure switch is mounted outside the room so that the operator is in a shielded area and not in the room with the x-ray unit for all exposures.
If an x-ray unit is turned off, then no x rays can be produced, even if the exposure switch is pressed. Also, the areas where the exposure switches are located are usually considered controlled areas. This means that they are in areas that cannot be accessed by the public unless they are escorted by someone from the facility, and that the exposure switch could not be randomly pushed by untrained individuals.
If an x-ray unit is turned on and not being used, the unit is usually stored up against the wall with the cone pointing toward the floor. This means that if an exposure button was pushed in this situation and an inadvertent x ray was taken, the primary x-ray beam would likely not be aimed at anyone.
Kennith "Duke" Lovins, CHP