Which of the following are requirements for mobile X-ray equipment exposure switches?

• A. 2 and 3
• B. 1 and 3
• C. 1 and 2
• D. 1, 2, and 3

Answer: (C)

The key safety idea here is that portable (mobile) x-ray exposure controls must require active, deliberate action by the operator and must be usable from a safe position. A dead-man style exposure switch ensures the x-ray beam only comes on while the operator is actively pressing the switch, so a momentary release stops exposure immediately. In addition, the switch needs to be positioned so the radiographer can control the exposure from a safe location, typically away from the primary beam, without needing to place hands into the field or inside the room.

These two features together—a dead-man type control and a reachable, safe control location—provide the core protection against accidental or prolonged exposures. Other features, like audible indicators or optional interlocks, are helpful but not required in every standard, which is why the two essential requirements are the ones that matter most here.